JP2005155793A - Hydraulic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic damper in which the flexural stiffness and heat radiating ability can be improved while suppressing the increase of its size and weight to a minimum. <P>SOLUTION: When the outer tube 11 of the hydraulic damper D in a suspension apparatus is attached to a knuckle via a bracket 11a, large stress concentration occurs at the fixed portion of the outer tube 11 to the bracket 11a. The stress concentration can be relieved by improving the flexural stiffness of the outer tube 11 through fixing annular reinforcing members 26 by welds w on the inside peripheral surface of the outer tube 11 and the outside peripheral surface of an inner cylinder 12. Further, the heat radiating ability can be improved by effectively transferring the heat generated by a hydraulic damping force from the inner cylinder 12 to the outer tube 11 via the reinforcing members 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic shock absorber used for, for example, a strut suspension device of an automobile.

Such a hydraulic shock absorber is known, for example, from Patent Document 1 below. In this hydraulic shock absorber, the outer periphery of an inner cylinder into which a piston is slidably fitted is surrounded by an outer tube, and the inner cylinder and the outer tube are integrally connected at their lower end and upper end.
No. 5-6425

  By the way, if the hydraulic shock absorber used in the strut suspension device of an automobile has insufficient bending rigidity, the camber and caster of the tire may change and the characteristics of the suspension device may be affected. This problem is particularly noticeable when the hydraulic shock absorber is made of aluminum and has low bending rigidity.

  In this regard, the above-mentioned conventional ones are difficult to ensure sufficient bending rigidity because the inner cylinder and the outer tube are connected only at the lower end and the upper end. It was necessary to increase the outer diameter of the tube or increase the thickness of the outer tube. However, when the outer diameter of the outer tube of the hydraulic shock absorber is increased, there is a problem that it is difficult to store the outer tube in the tire house, and when the outer tube is thickened, there is a problem that the weight is increased.

  The hydraulic shock absorber generates heat by the hydraulic damping force generated by the movement of the piston, but if the inner cylinder and outer tube are connected only at the lower end and upper end, the heat generated inside the inner cylinder is transferred to the outer tube. There is a problem that heat cannot be transmitted efficiently and the heat dissipation of the hydraulic shock absorber is reduced.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to increase its bending rigidity and heat dissipation while minimizing an increase in the size and weight of a hydraulic shock absorber.

  In order to achieve the above object, according to the invention described in claim 1, a piston rod, a piston provided on the piston rod, an inner cylinder in which the piston is slidably fitted, and an outer periphery of the inner cylinder The outer tube that fits into the inner cylinder, the oil filled in the inner cylinder and the outer tube, and the axial movement of the piston relative to the inner cylinder open and close, and the damping force is generated by the viscous resistance of the oil that passes therethrough In the hydraulic shock absorber provided with the throttle valve, a hydraulic shock absorber is proposed in which the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer tube are integrally fixed at least at an intermediate portion in the axial direction thereof. .

  According to the configuration of the first aspect, since the outer peripheral surface of the inner cylinder of the hydraulic shock absorber and the inner peripheral surface of the outer tube are integrally fixed at least at an intermediate portion in the axial direction thereof, an increase in size and weight is minimized. The inner cylinder and the outer tube are tightly integrated while increasing the bending rigidity of the hydraulic shock absorber, and the deformation of the hydraulic shock absorber prevents the tire camber and caster from changing and the suspension device characteristics from changing. Can do. Moreover, even if the temperature of the inner cylinder rises due to the heat generated when the mechanical energy is converted into heat energy by the damping force due to the hydraulic pressure, the heat is efficiently transferred to the outer tube to dissipate it to the atmosphere, and the hydraulic shock absorber The heat dissipation can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 and 2 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a hydraulic shock absorber, and FIG. 2 is a sectional view taken along line 2-2 of FIG.

  As shown in FIGS. 1 and 2, a hydraulic shock absorber D for an automobile strut suspension device includes a bottomed cylindrical outer tube 11 whose lower end is closed and whose upper end is open, and the lower end is attached. The portion 11a is fastened to a knuckle (not shown) with a bolt. A cylindrical inner cylinder 12 is coaxially arranged inside the outer tube 11 so as to share the axis L, and a valve block 13 is arranged between the lower end of the inner cylinder 12 and the bottom wall of the outer tube 11. The rod guide 14 abutting on the upper end of the inner cylinder 12 and the seal holder 15 superimposed on the upper surface thereof are fixed to the upper end of the outer tube 11 by caulking.

  The piston rod 17 that is slidably supported by the rod guide 14 and penetrates the seal member 16 provided in the center of the seal holder 15 in a liquid-tight manner has a mounting portion 17a at its upper end attached to a body frame (not shown) to a rubber bush joint. And a piston 18 provided at the lower end thereof is slidably fitted to the inner cylinder 12. A stopper rubber 19 is provided at an intermediate portion of the piston rod 17, and the amount of protrusion of the piston rod 17 at the time of full rebound is regulated by the stopper rubber 19 coming into contact with the rod guide 14.

  The inside of the inner cylinder 12 is partitioned into an upper chamber 20 and a lower chamber 21 by a piston 18, and a throttle valve 22 with a check function for connecting the upper chamber 20 and the lower chamber 21 is provided in the piston 18. Further, an outer chamber 23 is formed between the outer tube 11 and the inner cylinder 12, and a communication passage 13 a formed in the valve block 13 to connect the outer chamber 23 and the lower chamber 21 of the inner cylinder 12, Throttle valves 24 with check functions are provided. The upper chamber 20, the lower chamber 21, and the outer chamber 23 are filled with oil 25. The upper portion of the outer chamber 23 functions as a reservoir filled with air.

  Two reinforcing members 26 and 26 forming an annular shape between the inner peripheral surface of the outer tube 11 and the outer peripheral surface of the inner cylinder 12 are fixed by welding w. The reinforcing members 26, 26 are provided with a plurality of through holes 26a. The fixing positions of the reinforcing members 26 are set to the outside in the direction of the axis L from the position 18U of the piston 18 at the time of full rebound and the position 18L of the piston 18 at the time of full bump. That is, the reinforcing members 26 are fixed outside the sliding range of the piston 18.

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

  When the piston rod 17 rebounds from the outer tube 11, the throttle valves 22 provided on the piston 18 perform a throttle function and the throttle valves 24 provided on the valve block 13 are opened. As a result, the oil 25 in the upper chamber 20 of the inner cylinder 12 whose volume decreases with the upward movement of the piston 18 flows into the lower chamber 21 of the inner cylinder 12 while passing through the throttle valve 22 of the piston 18. At this time, a damping force is generated by the viscous resistance of the oil 25 passing through the throttle valves 22. At this time, the oil 25 corresponding to the volume of the piston rod 17 projecting from the upper chamber 20 through the rod guide 14 passes through the throttle valve 24 opened from the outer chamber 23 of the outer tube 11 to the valve block 13. Then, it flows into the lower chamber 21 of the inner cylinder 12 without resistance.

  On the other hand, when the piston rod 17 is pressed into the outer tube 11, the throttle valves 22 provided on the piston 18 are opened, and the throttle valves 24 provided on the valve block 13 exhibit a throttle function. As a result, the oil 25 pushed out from the lower chamber 21 in which the volume of the inner cylinder 12 decreases passes through the throttle valves 22 of the piston 18 without resistance and flows into the upper chamber 20 in which the volume increases. At this time, the oil 25 corresponding to the volume of the piston rod 17 inserted into the upper chamber 20 through the rod guide 14 flows from the lower chamber 21 through the throttle valve 24 of the valve block 13 into the outer chamber 23. At that time, a damping force is generated by the viscous resistance of the oil 25 passing through the throttle valves 24.

  As described above, when the outer tube 11 having the lower end connected to the suspension arm and the piston rod 17 having the upper end connected to the vehicle body frame relatively move in the direction of the axis L to generate a damping force, the hydraulic shock absorber A bending moment acts on D. When the hydraulic shock absorber D is bent and deformed by this bending moment, the camber and caster of the tire may change and the characteristics of the suspension device may be affected. Therefore, the bending deformation of the hydraulic shock absorber D can be minimized. desirable.

  In the present embodiment, since the annular reinforcing members 26 and 26 are fixed between the inner peripheral surface of the outer tube 11 and the outer peripheral surface of the inner cylinder 12 at the intermediate portion in the direction of the axis L of the hydraulic shock absorber D by welding w. The bending rigidity of the hydraulic shock absorber D can be increased by indirectly fixing the outer tube 11 and the inner cylinder 12 via the members 26 and 26. In addition, the outer diameter of the hydraulic shock absorber D is not increased by the reinforcing members 26, 26, and the weight is increased only by the weight of the reinforcing members 26, 26. Further, since the through holes 26a are formed in the reinforcing members 26, 26, not only the flow of the oil 25 and the air in the outer tube 11 is not disturbed, but also the weight of the reinforcing members 26, 26 is increased by the through holes 26a. Can be reduced.

  If the reinforcing members 26 and 26 are press-fitted into the outer tube 11 and the inner cylinder 12, the inner cylinder 12 may be deformed and the smooth sliding of the piston 18 may be hindered, but the reinforcing members 26 and 26 are fixed by welding w. As a result, smooth sliding of the piston 18 can be ensured.

  Furthermore, even if the temperature of the inner cylinder 12 rises due to heat generated by converting mechanical energy attenuated with the movement of the piston 18 into heat energy, the heat is transferred to the outer tube 11 via the reinforcing members 26 and 26. By transmitting, it is effectively dissipated into the atmosphere, and the heat dissipation of the hydraulic shock absorber D can be improved.

  3 and 4 show a second embodiment of the present invention. FIG. 3 is a longitudinal sectional view of the hydraulic shock absorber, and FIG. 4 is a sectional view taken along line 4-4 of FIG. In the second embodiment, the same reference numerals as those in the first embodiment are assigned to the members corresponding to the members in the first embodiment, and the duplicate description is omitted.

  The second embodiment does not include the reinforcing members 26 and 26 of the first embodiment, but instead the outer tube 11 and the inner cylinder 12 are integrally coupled by eight ribs 27 extending radially. Such a member can be easily formed by, for example, extrusion or drawing, and after the member is cut to a predetermined length, unnecessary portions of the inner cylinder 12 and the ribs 27 may be cut off by machining. Since the outer tube 11 and the inner cylinder 12 are integrated by the eight ribs 27..., The cross section thereof becomes a cross section similar to the honeycomb structure, and a large resistance against bending load can be exhibited. Also according to the second embodiment, the outer tube 11 and the inner cylinder 12 are indirectly fixed via the ribs 27, so that the bending rigidity and the heat dissipation of the entire hydraulic shock absorber D are increased, and the same as in the first embodiment. The effect of this can be achieved.

  In addition, the member integrally provided with the outer tube 11, the inner cylinder 12, and the ribs 27 can be manufactured by casting in addition to extrusion and drawing.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the same reference numerals as those in the first embodiment are assigned to the members corresponding to the members in the first embodiment, and the duplicate description is omitted.

  In the second embodiment, the outer tube 11 and the inner cylinder 12 are integrally coupled by eight ribs 27 extending radially. In the third embodiment, instead of the radially extending ribs 27..., The outer tube 11 and the inner cylinder 12 are integrally coupled by a single spirally extending rib 28. The outer tube 11, the inner cylinder 12, and the rib 28 can be fixed by welding w. Also according to the third embodiment, the outer tube 11 and the inner cylinder 12 are indirectly fixed via the ribs 28, so that the bending rigidity and the heat dissipation of the entire hydraulic shock absorber D are improved, and the same as in the first embodiment. The effect can be achieved.

  Instead of fixing the rib 28 to the outer tube 11 and the inner cylinder 12 by welding w, it is possible to cast the outer tube 11 and the inner cylinder 12 integrally provided with the rib 28 using a core.

  6 and 7 show a fourth embodiment of the present invention. FIG. 6 is a longitudinal sectional view of the hydraulic shock absorber, and FIG. 7 is a sectional view taken along line 7-7 in FIG. In addition, in 4th Example, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol as 1st Example to the member corresponding to the member of 1st Example.

  The fourth embodiment does not include the reinforcing members 26, 26 of the first embodiment nor the ribs 27,..., 28 of the second and third embodiments. Instead, the outer tube 11 has a six-section cross section. .. And 6 recesses 11c... Are continuously fixed to the inner cylinder 12 by welding w on the inner surface of the 6 recesses 11c having the smallest diameter. Since the outer tube 11 having such a shape can be easily formed by extrusion or drawing, it can be manufactured at low cost. Moreover, since the reinforcing members 26 and 26 and the ribs 27... 28 are not necessary, the number of parts can be reduced. According to the fourth embodiment, by directly fixing the outer tube 11 and the inner cylinder 12, the bending rigidity and heat dissipation of the entire hydraulic shock absorber D are enhanced, and the same effects as the first embodiment are achieved. can do.

  Next, a fifth embodiment of the present invention will be described with reference to FIG.

  The fifth embodiment is a modification of the fourth embodiment. The outer tube 11 of the fourth embodiment has a corrugated shape in which convex portions 11b and concave portions 11c are continuous. The outer tube 11 has a square cross section that circumscribes the inner cylinder 12, and the central part of the four sides thereof is fixed to the inner cylinder 12 by welding w. According to the fifth embodiment, the same function and effect as the fourth embodiment can be achieved.

  9 and 10 show a sixth embodiment of the present invention. FIG. 9 is a longitudinal sectional view of the hydraulic shock absorber, and FIG. 10 is a sectional view taken along line 10-10 of FIG. In addition, in 6th Example, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol as 1st Example to the member corresponding to the member of 1st Example.

  The sixth embodiment does not include the reinforcing members 26, 26 of the first embodiment nor the ribs 27,..., 28 of the second and third embodiments. Instead, the axis L of the outer tube 11 having a basically circular cross section is used instead. A recess 11d is formed in the middle of the direction, and this recess 11d is fixed to the inner cylinder 12 by welding w. According to the sixth embodiment, by directly fixing the outer tube 11 and the inner cylinder 12, the bending rigidity and heat dissipation of the entire hydraulic shock absorber D are enhanced, and the same effects as the first embodiment are achieved. Furthermore, by arranging tires and wheels in the space formed by the recess 11d of the outer tube 11, the degree of freedom in the layout of the hydraulic shock absorber D can be increased.

  11 and 12 show a seventh embodiment of the present invention. FIG. 11 is a longitudinal sectional view of the hydraulic shock absorber, and FIG. 12 is a sectional view taken along line 12-12 of FIG.

  The seventh embodiment is a modification of the sixth embodiment, in which the outer tube 11 has a simple cylindrical shape having no recess 11d, and the inner cylinder 12 is eccentric with respect to the outer tube 11, so that the inner tube The outer peripheral surface of the inner cylinder 12 is welded to the peripheral surface. In the seventh embodiment, in addition to the same effects as the sixth embodiment, the length of the welded portion is increased to further increase the strength, and the maximum radius of the hydraulic shock absorber D is reduced to the radius of the inner cylinder 12. Thus, a further effect of increasing the degree of freedom of layout can be achieved.

  Next, an eighth embodiment of the present invention will be described with reference to FIG.

  The eighth embodiment is a modification of the seventh embodiment, in which the outer tube 11 is changed from a cylindrical shape to an elliptical cylindrical shape and welded to the outer peripheral surface of the inner cylinder 12 at two locations on the short diameter side. is there. In addition to the same effects as in the seventh embodiment, the eighth embodiment can achieve the further effect that the strength can be further increased because there are two welded portions.

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

  For example, in the embodiment, the hydraulic shock absorber D for the suspension device of the automobile is illustrated, but the present invention can be applied to the hydraulic shock absorber D for any other use.

1 is a longitudinal sectional view of a hydraulic shock absorber according to a first embodiment. 2-2 sectional view of FIG. Longitudinal sectional view of a hydraulic shock absorber according to the second embodiment Sectional view taken along line 4-4 in FIG. Vertical sectional view of a hydraulic shock absorber according to a third embodiment Vertical sectional view of a hydraulic shock absorber according to a fourth embodiment Sectional view along line 7-7 in FIG. The figure corresponding to the said FIG. 7 based on 5th Example. Vertical sectional view of a hydraulic shock absorber according to a sixth embodiment Sectional view taken along line 10-10 in FIG. Vertical sectional view of the hydraulic shock absorber according to the seventh embodiment 12-12 sectional view of FIG. The figure corresponding to the said FIG. 12 based on 8th Example.

Explanation of symbols

11 Outer tube 12 Inner cylinder 17 Piston rod 18 Piston 22 Throttle valve 24 Throttle valve 25 Oil L Axis

Claims (1)

A piston rod (17);
A piston (18) provided on the piston rod (17);
An inner cylinder (12) in which a piston (18) is slidably fitted;
An outer tube (11) fitted to the outer periphery of the inner cylinder (12);
Oil (25) filled in the inner cylinder (12) and the outer tube (11);
Throttle valves (22, 24) that open and close with relative movement of the piston (18) in the axis (L) direction with respect to the inner cylinder (12) and generate a damping force by the viscous resistance of the oil (25) passing therethrough ,
In the hydraulic shock absorber with
A hydraulic shock absorber in which the outer peripheral surface of the inner cylinder (12) and the inner peripheral surface of the outer tube (11) are integrally fixed at least at an intermediate portion in the axis (L) direction.

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