JP2005106111A - Manufacturing method for single cylinder type hydraulic shock absorber and its manufacturing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively perform injection of gas into a cylinder, insertion of a free-piston, and holding of a gas chamber in a manufacturing method for a single cylinder type hydraulic shock absorber. <P>SOLUTION: A mandrel 49 chucking the free-piston 5 at its tip portion is housed into a holder 48, and the holder 48 is airtightly fitted to an opening side of a cylinder 2. High pressure gas is supplied into the cylinder from a high pressure gas passage 60 through the inside of the holder 48. The free-piston 5 is mounted at a designated position by inserting the mandrel 49 into the cylinder 2. A punch 34 is pushed to the mandrel 49 in the cylinder so that an operating rod 38 of the hydraulic cylinder 37 is expanded, a pusher ring 41 is lowered by a tension rod 40, and a shrinker 29 is moved by connection of a tapered surface between a cone member 42 and a tapered member 32 to press a punch 34 on the mandrel 49 in the cylinder 2. Thus, the gas chamber is held by expanding a mechanical clinch portion to the inside surface of the cylinder 2 and by preventing slipping-out of the free-piston 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a single cylinder type hydraulic shock absorber in which a cylinder is defined by a free piston as a gas chamber and an oil chamber, and a manufacturing apparatus therefor.

  A single-cylinder hydraulic shock absorber is known as a hydraulic shock absorber that is mounted on an automobile suspension device or the like. A single cylinder type hydraulic shock absorber is defined by a free piston that defines a gas chamber in which high-pressure gas is sealed and a fluid chamber in which oil is sealed, and a piston with a piston rod connected to the oil chamber. The piston portion is provided with a damping force generator mechanism including an oil passage, a disk valve, an orifice, and the like.

  With this configuration, the damping force is generated by controlling the piston rod stroke with the fluid flow orifice and disk valve generated in the oil passage, and the change in volume in the cylinder due to the piston rod entering and leaving is detected in the gas chamber. This is compensated by compression and expansion of the high-pressure gas sealed in the container. The single-cylinder hydraulic shock absorber has a simple structure, and aeration is hardly caused by pressurizing the oil liquid in the oil chamber by the pressure of the high-pressure gas in the gas chamber, and a stable damping force can be obtained.

In the single cylinder type hydraulic shock absorber, it is necessary to enclose high pressure gas in a gas chamber formed by fitting a free piston in the cylinder. Therefore, for example, in Patent Document 1, a free piston ton is fitted into the opening of a cylinder having a gas filling inlet at the bottom, and an oil tank storing oil is attached to the piston rod from the opening of the cylinder. After inserting the piston connected to the cylinder, fill the upper part of the free piston in the cylinder with oil, and install the rod guide, oil seal and upper cap in the cylinder opening to seal the oil chamber, then the bottom of the cylinder Describes a method of manufacturing a single cylinder type hydraulic shock absorber in which gas is sealed from the inlet of the cylinder.
JP-A-10-26164

  In a single cylinder type hydraulic shock absorber, it is required to efficiently perform a process of fitting a free piston in a cylinder and enclosing high-pressure gas in a gas chamber. It is another object of the present invention to provide a method and apparatus for manufacturing a single cylinder hydraulic shock absorber capable of efficiently enclosing gas in a gas chamber.

In order to solve the above-mentioned problem, the invention according to claim 1 is a simple example in which a gas chamber and an oil chamber are defined in a cylinder by a free piston, and a piston to which a piston rod is connected is fitted in the oil chamber. A method of manufacturing a cylindrical hydraulic shock absorber, wherein a holder holding the free piston is hermetically fitted to an opening side of the bottomed cylindrical cylinder, and gas is filled into the cylinder through the holder. The free piston is inserted into the cylinder to define the gas chamber, and a protrusion is formed on the inner wall of the cylinder to restrict the movement of the free piston toward the opening.
The method of manufacturing a single cylinder type hydraulic shock absorber according to the invention of claim 2 is characterized in that, in the configuration of claim 1, the non-sliding region between the piston of the cylinder and the free piston that does not slide is provided. A protrusion is formed.
A method of manufacturing a single cylinder type hydraulic shock absorber according to the invention of claim 3 is characterized in that, in the configuration of claim 1 or 2, a support member is disposed on an outer periphery of the cylinder, and the support member and the cylinder are plastically deformed. These are combined with each other and the protrusion is formed.
Further, the invention according to claim 4 is the manufacture of a single cylinder type hydraulic shock absorber in which a gas chamber and an oil chamber are defined in a cylinder by a free piston, and a piston to which a piston rod is connected is fitted in the oil chamber. An apparatus, a mandrel that holds the free piston at the tip and can be inserted into the cylinder, and a holder that accommodates the mandrel and can be hermetically fitted to the opening side of the bottomed cylindrical cylinder And gas supply means for supplying gas into the holder, and pressing means for pressing punches from the outside of the cylinder toward the mandrel inserted into the cylinder.

According to the method for manufacturing a single cylinder type hydraulic shock absorber according to the invention of claim 1, after the gas is sealed in the cylinder and the free piston is fitted to form the gas chamber, the free piston is held by the protrusion. Therefore, the cylinder filled with the gas can be sent to the next process without using a special jig or the like.
According to the manufacturing method of the single cylinder type hydraulic shock absorber according to the invention of claim 2, since the piston and the free piston do not slide in the non-sliding region, the sealing performance may be impaired by the protrusion. Absent.
According to the method of manufacturing the single cylinder type hydraulic shock absorber according to the invention of claim 3, the support member can be attached to the cylinder at the same time when the protrusion is formed.
Further, according to the single cylinder hydraulic shock absorber manufacturing apparatus according to the invention of claim 4, a gas supply is performed by fitting a holder containing a mandrel holding a free piston into an opening of a bottomed cylindrical cylinder. The gas is filled into the cylinder through the holder by means, the mandrel is inserted into the cylinder, the free piston is fitted into a predetermined position to form the gas chamber, and then the protrusion is formed on the inner wall of the cylinder by the punch means. Thus, the movement of the free piston toward the cylinder opening can be restricted and the gas chamber can be held.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
A single cylinder type hydraulic shock absorber manufactured by the manufacturing method and apparatus according to the present embodiment will be described with reference to FIGS.
As shown in FIG. 10, the single cylinder hydraulic shock absorber 1 has a rod guide 3 and an oil seal 4 attached to the opening of a bottomed cylindrical cylinder 2, and a free piston 5 on the bottom side of the cylinder 2. It is slidably fitted. The cylinder 2 is defined by a free piston 5 into a gas chamber 6 on the bottom side and an oil chamber 7 on the other end side. The gas chamber 6 is filled with high-pressure gas, and the oil chamber 7 is filled with oil liquid. It is enclosed.

  A piston 8 is slidably fitted in the oil chamber 7 of the cylinder 2, and the piston 8 divides the oil chamber 7 into two chambers, a cylinder upper chamber 7A and a cylinder lower chamber 7B. One end of a piston rod 9 is connected to the piston 8 by a nut 10, and the other end of the piston rod 9 is slidably and liquid-tightly inserted into the rod guide 3 and the oil seal 4 to extend to the outside. Has been issued.

  The piston 8 is provided with an extension side oil passage 11 and a contraction side oil passage 12 that communicate between the cylinder upper and lower chambers 7A and 7B. The extension side oil passage 11 and the compression side oil passage 12 are respectively provided with an extension side damping force generating mechanism 13 and a compression side damping force generation composed of an orifice, a disk valve and the like that control the flow of the oil to generate a damping force. A mechanism 14 is provided.

  With this configuration, during the extension stroke of the piston rod 9, as the piston 8 in the cylinder 2 slides, the oil in the cylinder upper chamber 7A flows into the cylinder lower chamber 7B through the extension-side oil passage 11 of the piston 8, A damping force is generated by the extension-side damping force generation mechanism 13. Further, during the contraction stroke, the oil in the cylinder lower chamber 7B flows to the cylinder upper chamber 7A through the contraction side oil passage 13, and the contraction side damping force generation mechanism 14 generates a damping force. At this time, the volume change of the oil chamber 7 due to the entry and exit of the piston rod 9 is compensated by the free piston 5 moving and compressing and expanding the high-pressure gas in the gas chamber 6.

  A mounting eye 15 for coupling to a suspension arm or the like (not shown) is coupled to the bottom of the cylinder 2, and a mounting portion 16 for coupling to the vehicle body side is provided at the tip of the piston rod 9. It has been. A spring seat 17 for receiving a suspension spring (not shown) interposed between the cylinder 2 and the vehicle body is attached to the outer peripheral portion on the upper end side of the cylinder 2. A rebound stopper 18 is attached to the piston rod 9. In addition to the spring seat 17, a bracket 19 (support member) for supporting exterior parts such as a sensor for an antilock brake system is attached to the outer peripheral portion of the cylinder 2.

Next, a structure for attaching the bracket 19 to the cylinder 2 will be described.
In the single cylinder hydraulic shock absorber 1, the expansion / contraction stroke range of the piston rod 9 is restricted. Thus, the sliding area of the piston 8 and the free piston 5 is limited in the cylinder 2, and the non-sliding area A of the piston 8 and the free piston 5 exists in the middle part of the cylinder 2.

  The bracket 19 attached to the outer peripheral portion of the cylinder 2 includes a cylindrical portion 20 fitted to the outer peripheral portion of the cylinder 2 and an attachment portion 21 for mounting exterior parts such as an ABS sensor. The bracket 19 is attached by connecting the cylindrical portion 20 fitted in the non-sliding region A of the cylinder 2 to the cylinder 2 by mechanical clinch. The mechanical clinch causes the overlapping portion between the cylindrical portion 20 and the cylinder 2 of the bracket 19 to be sheared from the outside by a punch and protrudes inward, whereby the concave portion formed on the outer periphery of the cylinder 2 and the inner portion of the cylindrical portion 20 These are coupled to each other by concave-convex fitting with convex portions formed on the periphery.

  As shown in FIGS. 11 and 12, the diameter D of the cylinder 2 is 44 mm, the thickness T of the cylinder 2 is 2.0 mm, the thickness t of the cylindrical portion 20 of the bracket 19 is 1.6 mm, and the axial length L is 20 mm. On the other hand, the mechanical clinch part 22 has a width W1 = 1.9 mm on the opening side in the concave part on the cylindrical part 20 side, a width W2 on the bottom side in the concave part on the cylindrical part 20 side = 1.0 mm, and the tip part of the convex part on the cylinder 2 side The width W3 is 3.0 to 4.0 mm, and six are arranged at equal intervals along the circumferential direction.

  Here, the mechanical clinch part 22 (protrusion part) protrudes from the inner peripheral surface of the cylinder 2, but the piston 8 and the free piston 5 do not slide in the non-sliding area A. There is no restriction or loss of sealing performance. Accordingly, the bracket 19 can be directly attached to the outer periphery of the intermediate portion of the cylinder 2 without using a member such as an outer tube, the structure is simple, the manufacturing cost is low, and the unsprung weight does not increase. Even if the oil in the oil chamber 7 leaks to the outside or enters the gas chamber 6 and the free piston 5 rises into the non-sliding region A, the free piston Since the rise of 5 is restricted, the piston rod 9 and the free piston 5 do not collide, and it is possible to prevent the generation of noise due to the collision, damage to the piston rod 9, and the like. Since the dimensions (width W1 and width W3) of the mechanical clinch portion 22 in the axial direction are sufficiently small, the present invention can be applied even when the non-sliding region A is small.

Next, a manufacturing method and a manufacturing apparatus for the single cylinder hydraulic shock absorber 1 according to this embodiment will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the single-cylinder hydraulic shock absorber manufacturing device 23 includes a clinch mechanism 24 and an insert mechanism 25.
The clinch mechanism 24 supports a substantially disk table 28 having an opening 28A in the center by a plurality of legs 27 erected on a base 26, and a plurality of (not shown) radially arranged on the table 28. 12 of them are supported by a bearing 30 so as to be movable in the radial direction. The shrinker 29 is fixed to the base member 31 attached to the bearing 30, the taper member 32 that is fixed to the upper outer peripheral side of the base member 31 and the outer peripheral portion is formed in a tapered shape, and the inner peripheral side of the taper member 32. The punch holder 33 is composed of three members. Six punches 34 are attached to the punch holder 33 corresponding to the clinching portions of the cylinder 2 and the bracket 20 to be coupled, and a cushion material 35 made of an elastic body such as rubber for holding the bracket 20 above and below the punch 34. Is installed. The punch 30 has a flat shape corresponding to the mechanical clinching part 22, and an angle of about 30 degrees is provided at the tip part in order to improve knockout performance.

  A pedestal 36 and a hydraulic cylinder 37 (pressing means) for holding the mounting portion eye 15 of the cylinder 2 inserted into the opening 28 are attached to the table 28. A disc-shaped plate 39 having an opening through which the leg 27 is inserted is attached to the distal end portion of the operating rod 38 of the hydraulic cylinder 37. The lower end portions of a plurality of tension rods 40 are coupled to the outer peripheral portion of the plate 39, and the upper end side of the tension rod 40 extends through the outer periphery of the table 28 to the upper side of the shrinker 29, and an annular pressure is provided at the front end portion thereof. Ring 41 is joined. A plurality (12 in the illustrated example) of cone members 42 having taper surfaces that engage with the taper surfaces of the taper member 32 of the shrinker 29 are attached to the inner peripheral portion of the pressure ring 41. The tapered member 32 and the cone member 42 have a tapered surface of about 10 degrees. When the operating rod 38 of the hydraulic cylinder 37 is extended and the pressure ring 41 is pulled down by the tension rod 40, the shrinker 29 is moved inward by the engagement of the tapered surface of the cone member 42 and the tapered member 32.

  A plurality (12 in the illustrated example) of air cylinders 44 are attached to the outer periphery of the table 28 via brackets 43. The air cylinder 44 is disposed on the back side of the base member 31 of the shrinker 29, and the operation rod 45 is connected to the corresponding base member 31, and the shrinker 29 is moved in the radial direction of the table 28 by the expansion and contraction of the operation rod 45. Can be made. The bracket 43 is provided with a passage 46 for supplying air to the air cylinder 44.

  The insert mechanism 25 is provided above the clinching mechanism 24 so as to be lifted and lowered by a driving device (not shown). In the insert mechanism 25, a mandrel 49 is inserted into a cylindrical holder 48 in which the opening side of the cylinder 2 can be fitted, and the mandrel 49 is attached to the tip of a rod 50 that is slidably inserted into the holder 48. Connected, it is movable in the axial direction and rotatable about the axis. The mandrel 49 is slightly smaller in diameter than the inner diameter of the cylinder 2, and a ring-shaped guide member 51 made of a soft elastic body is fitted in an annular groove on the outer peripheral portion. The outer peripheral portion of the guide member 51 protrudes slightly (about 0.01 mm) from the outer peripheral surface of the mandrel 49, and when the mandrel 49 is inserted into the cylinder 2, the outer peripheral surface contacts the inner peripheral surface of the cylinder 2. It is supposed not to. An annular groove 53 is formed on the outer periphery of the tip of the mandrel 49 so as to face the six punches 34 at the clinch position. Six notches 54 having the same interval as the interval of the six punches 34 are formed on the tip side from the annular groove 53 of the mandrel 49. As a result, in the state where the punch 34 has advanced toward the annular groove 53 side, the mandrel 49 is rotated by a predetermined angle (about 30 degrees), and the tip of the mechanical clinch part 22 and the notch 54 are aligned, so that the mandrel 49 is Can be pulled out from.

  Further, a small-diameter rod 55 is slidably inserted into the mandrel 49 and the rod 50, and an annular holding member 56 made of a soft elastic body such as rubber is provided at the tip of the rod 50 protruding from the mandrel 49. It is mated. The distal end of the small-diameter rod 55 is enlarged in diameter to form a flange portion 57. The small-diameter rod 55 is retracted and the holding member 56 is compressed in the axial direction by the flange portion 57, whereby the holding member 56 is expanded in diameter. can do. A circular recess 5A is formed on the upper surface of the free piston 5, and after inserting the holding member 56 into the recess 5A, the small diameter rod 55 is retracted to expand the diameter of the holding member 56. Can be chucked.

  An O-ring 58 that seals between the cylinder 2 and the O-ring 59 that seals the sliding portion with the rod 50 is attached to the holder 48 on the inner peripheral surface of the tip. A high-pressure gas passage 60 for supplying high-pressure gas to the inside of the holder 48 is provided on the side wall of the holder 48, and high-pressure gas supply means (not shown) is connected to the high-pressure gas passage 60.

Next, a process for manufacturing the single cylinder hydraulic shock absorber 1 using the single cylinder hydraulic shock absorber manufacturing apparatus 23 will be described.
As shown in FIGS. 1 and 3, after the tip of the mandrel 49 of the insert mechanism 25 protrudes from the holder 48 and the holding member 56 is inserted into the recess 5A of the free piston 5, the small-diameter rod 55 is retracted to hold the holding member. Increase the diameter of 56 and chuck the free piston 5. The cylinder 2 is inserted into the clinching mechanism 24, the mounting eye 15 is placed on the pedestal 36, the bracket 19 is fitted from above the cylinder 2, and set at a predetermined position. As shown in FIG. 5, the holder 48 is lowered to house the mandrel 49 that chucks the free piston 5 in the holder 48, and the upper end of the cylinder 2 set in the clinch mechanism 24 is fitted to the holder 48. Then, the space between the cylinder 2 is sealed by the O-ring 58. In this state, the high pressure gas is supplied from the high pressure gas passage 60 into the holder 48, and the cylinder 2 is filled with the high pressure gas.

  As shown in FIG. 6, the rod 50 is extended to insert the mandrel 49 and the free piston 5 into a predetermined position in the cylinder 2 where the annular groove 53 of the mandrel 49 faces the tip of the punch 34. At this time, since the mandrel 49 is guided by the guide member 51 made of a soft elastic body, the inner peripheral surface of the cylinder 2 is not damaged by contact with the mandrel 49. As a result, a gas chamber 6 in which high-pressure gas is sealed is formed on the bottom side of the cylinder 2 by the free piston 5.

  As shown in FIGS. 7 and 8, the operating rod 38 of the hydraulic cylinder 37 (see FIG. 1) is extended, the pressure ring 41 is pulled down by the tension rod 40, and the engagement of the cone member 42 and the taper member 32 results in the shrinker 29 Is moved inward, and the punch 34 is pressed toward the annular groove 53 of the mandrel 49. While the cushion member 35 presses and holds the bracket 19, the cylindrical portion 20 of the bracket 19 and the side wall of the cylinder 2 are plastically deformed between the punch 34 and the annular groove 53 by shearing force, and the six mechanical clinch portions 22. Is formed, and the bracket 19 is fixed to the cylinder 2.

The small diameter rod 55 is advanced, the chuck of the free piston 5 is released, and the mandrel 47 is rotated to align the notches 54 with the six mechanical clinch portions 22 protruding from the inner wall of the cylinder 2. As a result, the mandrel 47 can be detached from the mechanical clinching portion 22. The rod 50 is shortened, the mandrel 47 is pulled out from the cylinder 2, and the holder 48 is raised and detached from the cylinder 2. At this time, as shown in FIG. 9, the freepist 5 is held in contact with the mechanical clinching portion 22 protruding from the inner peripheral surface of the cylinder 2 and receives the pressure of the high-pressure gas in the gas chamber 6. The operating rod 38 of the hydraulic cylinder 37 is shortened to raise the pressure ring 41 and the cone member 42, and the shrinker 29 is moved backward by the air cylinder 44, so that the punch 34 is detached from the cylinder 2 and the bracket 19. In this manner, the bracket 19 can be attached to the cylinder 2, the free piston 5 can be fitted to the cylinder 2, and the high pressure gas can be sealed into the gas chamber 6. Since the free piston 5 is held by the mechanical clinching part 22, the cylinder 2 in which the high-pressure gas is sealed in the gas chamber 6 can be sent to the next step without using a special jig or the like.
Thereafter, the oil liquid is injected into the oil chamber 7, and the piston 8, the piston rod 9, the rod guide 3, the oil seal 4, and the like can be assembled to complete the single cylinder type hydraulic shock absorber 1.

It is a longitudinal section showing a schematic structure of a manufacturing apparatus of a single cylinder type hydraulic shock absorber concerning one embodiment of the present invention. FIG. 2 is a partial cross-sectional view of a shrinker portion of the apparatus shown in FIG. FIG. 2 is an enlarged view showing an insert mechanism of the apparatus shown in FIG. FIG. 4 is a cross-sectional view of a tip portion of a mandrel of the insert mechanism shown in FIG. FIG. 2 is a diagram showing a process of sealing high pressure gas in a cylinder in the apparatus shown in FIG. FIG. 2 is a diagram showing a process of inserting a mandrel and a free piston at a predetermined position in a cylinder in the apparatus shown in FIG. FIG. 2 is a diagram showing a process of performing mechanical clinching in the apparatus shown in FIG. FIG. 8 is an enlarged view showing a main part of FIG. FIG. 2 is a view showing a cylinder in a state where a bracket is attached, a free piston is fitted, and a high-pressure gas is sealed in a gas chamber by the apparatus shown in FIG. It is a longitudinal cross-sectional view of the single cylinder type hydraulic shock absorber manufactured by the manufacturing method of the single cylinder type hydraulic shock absorber of this invention, and its manufacturing apparatus. FIG. 11 is an enlarged view showing a bracket mounting portion of a cylinder of the single cylinder type hydraulic shock absorber shown in FIG. FIG. 12 is a transverse sectional view of the mechanical clinching part of FIG.

Explanation of symbols

1 Single cylinder hydraulic shock absorber, 2 cylinders, 5 free piston, 6 gas chamber, 7 oil chamber, 8 piston, 9 piston rod, 19 bracket (support member), 22 mechanical clinch part (protrusion part), 34 punch, 37 Hydraulic cylinder (pressing means), 48 holders, 49 mandrels, 60 high-pressure gas passage (gas supply means), A non-sliding area

Claims (4)

  A manufacturing method of a single cylinder type hydraulic shock absorber in which a gas chamber and an oil chamber are defined in a cylinder by a free piston, and a piston to which a piston rod is connected is fitted in the oil chamber. A holder holding the free piston is hermetically fitted to the opening side of the cylinder, gas is filled into the cylinder through the holder, and the free piston is inserted into the cylinder to define the gas chamber. And forming a projection on the inner wall of the cylinder to restrict the movement of the free piston toward the opening.   2. The method of manufacturing a single cylinder type hydraulic shock absorber according to claim 1, wherein the protrusion is formed in a non-sliding region where the piston and the free piston of the cylinder do not slide.   3. The unit according to claim 1, wherein a support member is disposed on an outer periphery of the cylinder, the support member and the cylinder are plastically deformed, and coupled to each other, and the protrusion is formed. Manufacturing method of cylindrical hydraulic shock absorber. A device for manufacturing a single cylinder type hydraulic shock absorber in which a gas chamber and an oil chamber are defined in a cylinder by a free piston, and a piston to which a piston rod is connected is fitted in the oil chamber. A mandrel that can be inserted into the cylinder while holding a piston, a holder that accommodates the mandrel and can be hermetically fitted to the opening side of the bottomed cylindrical cylinder, and gas is supplied into the holder An apparatus for manufacturing a single cylinder type hydraulic shock absorber, comprising: a gas supply means; and a pressing means for pressing a punch from the outside of the cylinder toward the mandrel inserted into the cylinder.

Images