GB2346947A

GB2346947A - Method and device for assembling hydraulic shock absorber

Info

Publication number: GB2346947A
Application number: GB0014175A
Authority: GB
Inventors: Takaaki Yamaura
Original assignee: Showa Corp
Current assignee: Showa Corp
Priority date: 1998-10-14
Filing date: 1999-10-13
Publication date: 2000-08-23
Anticipated expiration: 2019-10-13
Also published as: JP2000120754A; CN1287599A; GB0014175D0; JP4100783B2; ID26133A; GB2346947B; WO2000022320A1; BR9906872A; CN1109204C

Abstract

Am assembling device (10) for a hydraulic shock absorber (1), wherein the top part of an outer tube (2) of the hydraulic shock absorber (1) is held by a gas-sealed head (31), a sealing member (6) temporarily attached sealingly to the hydraulic shock absorber (1) is pushed upward above the upper end of the outer tube (2) by a vacuum sucking force of a vacuum head (32), the gas of a specified pressure is sealed into the hydraulic shock absorber (1) through a gas feed path (49) in the gas-sealed head (31), the sealing member (6) is held pressingly on an inner tube (3) at an upper end regular assembly position by the vacuum head (32), the gas-sealed bead (31) is moved upward from the upper part of the outer tube (2), and the upper end of the outer tube (2) is deformed in inner radial direction by a caulking device (33) so as to install the sealing member (6) at the regular assembly position.

Description

2346947 SPECMCAnON METHOD AND APPARATUS FOR ASSEMBIJNG HYDRAULIC SHOCK

ABSORBER FIELI) OF THE D%TVENnON The present invention relates to a method and an apparatus for assembling a hydraulic shock absorber.

BACKGROLIND ART Methods for assembling a hydraulic shock absorber where an ml storage chamber and a gas chamber are formed between inner and outer tubes of the hydraulic shock absorber and upper portions of the inner and outer tubes are sealed by a sealing member are &-4J-osed in Japanese Patent Application Laid-Open (JP-A) No. 63-219931 (hereinafter referred to as prior art 1) and Japanese Patent Publication (JP-B) No. 61-16839 (hereinafter referred to as prior art 2).

In the prior art 1, a sealing member is assembled in an upper and r periphery of an outer tube of a hydraulic shock absorber with -a clearance between the sealing member and the upper and inner periphery, gas with a predetermined pressure is injected from a gas injection head into the hydraulic shock absorber through dearance between the upper and inner periphery of the outer tube and the sealing member is sealed in the hydraulic shock absorber. Thereafter the clearance is dosed to fix the sealing member in a sealing manner by deforming an upper portion of the outer tube.

In the prior art 2, a jig is inserted inside a sealing lip of a sealing member disposed in an upper portion of an outer tube of a hydraulic shock -2absorber, the sealing lip is expanded in its radial direction by the jig to form a gas introducing passage, gas with a predetermined pressure is injected into the hydraulic shock absorber through the gas introducing path, and, after gas is injected, the gas injected is sealed in the hydraulic shock absorber due to a 5 restoring force of the sealing lip.

In prior art 1, however, since there exists clearance between the upper and inner periphery of the outer tube of the hydraulic shock absorber and the sealing member, there is a drawback that foreign matter may enter into the hydraulic shock absorber in the course of conveying the hydraulic shock absorber to an assembling apparatus and a cover must be provided for dosing the clearance.

In prior art 2, there is a drawback that, when the sealing lip of the sealing member fixed regularly in the hydraulic shock absorber is expanded by the jig, the sealing lip of the sealing member may be damaged and the quality of the sealing member may deteriorate.

DISCLOSURE OF TM DMMMON

An object of the present invention is to improve an assembling quality of a hydraulic shock absorber while facilitating management of parts for the hydraulic shock absorber, where foreign matter is prevented from entering into the hydraulic shock absorber and a sealing member is not damaged in the course of assembling the hydraulic shock absorber.

The present invention provides a method of assembling a hydraulic shock absorber in which an oil storage chamber and a gas chamber above the oil storage chamber are formed between inner and outer tubes of the hydraulic shock absorber and upper portions of the inner and outer tubes are sealed by a sealing member, wherein an assembling apparatus is used, comprising a gas -3injection head which charges oil in the hydraulic shock absorber and holds an upper portion, of an outer tube of the hydraulic shock absorber temporarily fitted in an upper inner peripheral portion of the outer tube with the sealing member and which has a vent path for injecting gas into the hydraulic shock absorber; a vacuum head in the gas injection head, which has a vacuum suction path for applying vacuum suction force in a space positioned above the sealing member temporarily mounted to the hydraulic shock absorber and which presses the sealing member on a regular assembling position at an upper end of the inner tube within the outer tube, and a caulking device which is positioned outside the hydraulic shock absorber, which deforms an upper end of the outer tube inwardly to fix the sealing member at the regular assembling position, wherein the assembling method comprising the steps dholding the upper portion of the outer tube of the hydraulic shock absorber by the gas injection head, lifting the sealing member temporarily mounted to the hydraulic shock absorber above the upper end of the outer tube by the vacuum suction force of the vacuum head, injecting gas with a predetermined pressure into the hydraulic shock absorber from the vent path of the gas injection head;pressing and holding the sealing member at the regular assembling position at the upper end of the inner tube; moving the gas injection head above the upper portion of the outer tube; and deforming the upper end of the outer tube by the caulking device to mount the sealing member at the regular assembling position.

The present invention provides also an assembling apparatus for a hydraulic shock absorber in which an oil storage chamber and a gas chamber above the oil storage chamber are formed between inner and outer tubes of the hydraulic shock absorber and upper portions of the inner and outer tubes are sealed by a sealing member, the assembling apparatus comprising a gas -4 injection head which charges oil in the hydraulic shock absorber and holds an upper portion of an outer tube of the hydraulic shock absorber temporarily fitted in an upper inner peripheral portion of the outer tube with the sealing member and which has a vent path for injecting gas into the hydraulic shock absorber; a vacuum head in the gas injection head, which has a vacuum suction path for applying vacuum suction force in a space positioned above the sealing member temporarily mounted to the hydraulic shock absorber and which presses the sealing member on a regular assembling position at an upper end of the inner tube within the outer tube, and a caulking device which is positioned outside the hydraulic shock absorber, which deforms an upper end of the outer tube inwardly to fix the sealing member at the regular assembling position, wherem an upper portion of the outer tube of the hydraulic shock absorber is held by the gas injection head, the sealing member temporarily mounted to the hydraulic shock absorber is lifted above the upper end of the outer tube due to the vacuum suction force of the vacuum head, gas with a predetermined pressure is injected into the hydraulic shock absorber from the vent path of the gas injection head, the sealing member is pressed and held at the regular assembling position at the upper end of the inner tube by the vacuum head, the gas injection head is moved above the upper portion of the outer tube, and the upper end of the outer tube is deformed inwardly by the caulking device so that the sealing member can be mounted at the regular assembling position.

BRIEF DESCRIMON OF THE DRAWINGS Figs. 1 are illustrative views showing an assembling apparatus, where (A) is a front view and (B) is a side view.

Fig. 2 is an exploded sectional front view where a main portion of a hydraulic shock absorber is shown.

Fig. 3 is a sectional view showing the hydraulic shock absorber set in the assembling apparatus.

Figs. 4 are sectional views showing a cauDdng margin being measured by the assembling apparatus; Fig. 5 is a sectional view showing gas injection being performed by the assembling apparatus; Fig. 6 is a sectional view showing a caulking being performed by the assembling apparatus; and Figs. 7 are sectional views showing a performance evaluation being performed by the assembling apparatus.

BEST MODE FOR CARRYING OUT THE P%A=ON

An assembling apparatus 10 shown in Fig. 1 injects and seals gas in a hydraulic shock absorber 1. As shown in Fig. 2, the hydraulic shock absorber 1 has an inner tube 3 inserted into an outer tube 2 with a bottom wall, a piston rod 4 shdably inserted into the inner tube 3, and a rod guide 5. A sealing member (oil seal) 6 and an end plate 7 are mounted on an upper end of the inner tube 3 positioned within the outer tube 2, and the rod guide 5, the sealing member 6 and the end plate 7 are mounted and retained by an upper end caulicing portion 2A of the outer tube 2 at a stage of completion of assembling work effected by the assembling apparatus 10. At this time, in the hydraulic shock absorber 1, oil is charged in an inside cavity of the inner tube 3 serving as an oil chamber, an oil storage chamber and a gas chamber above the oil storage chamber are formed between the outer tube 2 and the inner tube 3, and upper portions of the outer tube 2 and the inner tube 3 are sealed by the above sealing member 6. In the hydraulic shock absorber 1, an -6oil returning passage 8 is formed in the rod guide 5, so that oil carried out from the oil chamber of the inner tube 3 by the piston rod 4 at a time of forward/backward movement thereof is removed by a sealing lip of the sealing member 6 and the oil removed can be returned back to the oil storage chamber between the outer tube 2 and the inner tube 3 through the oil returning passage 8.

The assembling apparatus 10 comprises a hydraulic shock absorber supporting section 11, a gas injection section 12, a hydraulic shock absorber performance evaluation section 13, and a column 10A- The hydraulic shock absorber supporting section 11 includes a damp base 22 movable upward and downward along a slide guide 21 provided at a front face of the column 10A, and the clamp base 22 can be moved upward and downward by a damp cylinder 23, so that an upper portion of the outer tube 2 of the hydraulic shock absorber 1 vertically supported on the damp base 22 can be set at a gas injection work position where gas is injected into the hydraulic shock absorber 1 by the gas injection section 12. At this time, in the hydraulic shock absorber 1, though the rod guide 5 is fitted to the outer tube 2 with pressure, the sealing member 6 is merely attached temporarily in an upper inner periphery of the outer tube 2 (such a clearance through which foreign matter enters is not formed between the sealing member 6 temporarily attached and the inner periphery of the outer tube 2, but the sealing member 6 can be slid against the outer tube 2 by external force) and the upper end caulking portion 2A of the outer tube 2 has not yet been worked.

The gas injection section 12 has a gas injection head 31, a vacuum head 32, and a caulking device 33. That is, the gas injection section 12 has an ascending/descending base 35 movable upward and downward along a slide guide 34 provided at a front face of the column 10A, the ascending/descending -7 base 35 can be moved upward and downward by an ascending/descending cylinder 36, the above vacuum head 32 is supported by the ascending/descending base 35 in a suspended manner, and the above gas injection head 31 is mounted about the vacuum head 32. Also, in the gas injection section 12, a caulking housing 37 of the caulking device 33 is fixed on a front face of the column 10A, and the gas injection head 31 and the vacuum head 32 are disposed within the housing 37, The gas injection head 31 includes an outer cylinder 41 mounted air tightly about an inner cylinder 51 described later of the vacuum head 32 suspended from the ascending/descending base 35 moved upward and downward by the ascending/descending cylinder 36, a cavity inside the outer cylinder 41 is partitioned into an upper air chamber 43A and a lower air chamber 43B by a piston 42 fixed on an outer periphery of the inner cyhnder 51 of the vacuum head 32, an air supplying passage 45 connected to an air pressure device 44 provided on a side of the ascending/descending base 35 is formed in the outer qhnder 41, and the air supplying passage 45 can be connected to one of the upper air chamber 43A and the lower air chamber 43B in a switching manner. Air pressure is supplied in the lower air chamber 43B (the upper air chamber 43A is opened to the atmosphere) in a state where the hydrauhc shock absorber 1 is set at the gas injection working position by the hydraulic shock absorber supporting section 11 and the vacuum head 32 presses and hold the end plate 7 of the hydrauhc shock absorber 1 as described later so that the gas injection head 31 is moved downward about the vacuum head 32 and an upper portion of the outer tube 2 of the hydraulic shock absorber I can be held by a distal end holding portion 3 1A At this time, in the gas injection head 3 1, an O-ring 46 positioned at an inner periphery of the dista]. end holding portion 31A is brought into dose contact with an outer -8 peripheral portion of the outer tube 2 and a stepped portion 3 1B provided at an inner periphery of the distal end holding portion 3 1A is caused to abut an upper end face of the outer tube 2, so that an inner peripheral face of the outer tube 2 is flush with a portion of an inner peripheral face of the gas injection head 31 positioned above the stepped portion 31B of the gas injection head 31 (Fig. 4(B)).

A level gauge 47 such as a dial gauge or the like is provided on the ascending/descending base 35 supporting the vacuum head 32 in a suspended manner (Fig. 4(A)), and the level gauge 47 can measure a relative position of the gas injection head 31 to the vacuum head 32. The level gauge 47 can measure a projecting amount of an upper end portion of the outer tube 2 to the end plate 7, namely a cauUdng margin H of the outer tube 2, in a state where the stepped portion 31B of the distal end holding portion 31A of the gas injection head 31 abuts on the upper end face of the outer tube 2 and a distal end portion of the vacuum head 32 presses and hold the end plate 7 (Fig. 4(B)).

Also, the gas injection head 31 has therein a vent passage 49 connected to a gas supplying device 48 provided on a side of the ascending/descending base 35. Thereby, the gas injection head 31 can inject and seal gas supplied by the gas supplying device 48 thmugh the vent passage 49 in an upper portion of the outer tube 2 and thus in the gas chamber between the outer tube 2 and the inner tube 3 from the oil returning passage 8 formed in the rod guide 5 in a state where the sealing member 6 is lifted above the upper end of the outer tube 2 by the vacuum head 32, as described later.

As described above, the vacuum head 32 has the inner cylinder 51 supported suspended on the ascending/descending base 35 moved upward and downward by the ascending/descending cylinder 36, the inner cylinder 51 is mounted air-tightly in the outer cylinder 41 of the gas injection head 31, and -9an outside guide 77C of a chuck device 77 described later is inserted air-tightlY in a hollow inside portion of the inner cyhnder 5 1. Then, the vacuum head 32 has in the inner cylinder 51 a vacuum suction passage 53 connected to a vacuum device 52 provided on a side of the ascending/descending base 35.

The vacuum head 32 apphes vacuum suction force to a space above the sealing member 6 temporarily fitted in the outer tube 2 of the hydraulic shock absorber 1 by using the vacuum suction passage 53 to suck the sealing member 6 and the end plate 7 upwardly, and it draws up the sealing member 6 above the upper end of the outer tube 2 and above an open end of the vent passage 49 positioned at the inner peripheral face of the gas injection head 3 1, so that gas can be supplied to an upper portion of the outer tube 2 by the gas injection head 3 1.

The vacuum head 32 is moved upward and downward by the ascending/descending cylinder 36, as described above, where (a) it is moved downward when it presses and holds the end plate 7 in order to measure a caulking margin of the outer tube 2, (b) it is moved upward before the seahng member 6 is ascended above the open end of the vent passage 49 positioned at an inner peripheral face of the gas injection head 31, and (q) it is moved downward when the sealing member 6 and the end plate 7 are pressed on the upper end of the inner tube 3 within the outer tube 2 and held at the regular assembling position after gas has been injected in the upper portion of the outer tube 2.

The caulking device 33 supports a pivoting body 61 via bearings to upper and lower supporting portions of the caulking housing 37 fixed on a front face of the column IOA The pivoting body 61 is disposed coa.Nially with the gas injection head 31 and the vacuum head 32, and it is belt- driven by a Pivoting motor 62. Reference numeral 6 1A denotes a belt pulley. The -10pivoting body 61 rotatably supports three rollers 63 disposed via bearings at equal intervals along its penpheral direction, and it is rotated about the upper end of the outer tube 2 of the hydraulic shock absorber 1. The pivoting body 61 has a cam member 64 slid upward and downward by a fork 66 swung 5 upward. and downward by a cam ascending/descending cylinder 65, a cam face 64A of the cam member 64 is engaged with pins 63A of the respective rollers 63, and the respective rollers 63 are advanced totretracted from its original position against the upper end of the outer tube 2 according to upward and downward movements of the cam member 64. Incidentally, the fork 66 is swung upward and downward about a swinging fulcrum 67, and a cam follower 66A positioned at a distal end of the fork 66 is engaged with a peripheral groove 66B of an outer periphery of the cam member 64, so that the cam member 64 can be slid upward. and downward- The damp base 22 is moved. upward. by the above described damp cylinder 23 to position the hydraulic shock absorber 1 to a caulldng work position in a state where each roller 63 is advanced to a position facing the upper end face of the outer tube 2 and the pivoting body 61 is rotating, the upper end face of the outer tube 2 is seated on a roller face of each roller 63, and a predetermined caulking load is applied to the upper end of the outer tube 2 to deform the upper end of the outer tube 2 inwardly and form an upper end caulked portion 2A, so that the sealing member 6 and the end plate 7 can be mounted at the regular assembling position of the upper end of the inner tube 3.

The hydraulic shock absorber performance evaluation section 13 has an ascending/clescending head 72 movable upward and downward along slide guides 71, 71 provided on a front face of the column 10A, and the ascendingdescending head 72 is coupled to a connecting rod 75 of a crank -11 device 74 driven by an ascending/descendmg motor 73. The ascending/descending head 72 has an automatic chuck device 77(rod holding device) provided with a load gauge 76, and chuck claws 77A, an inside guide 77B and an outside guide 77C of the chuck device 77 are inserted into a vacuum inner portion of the inner cylinder 51 of the vacuum head 32, and the piston rod 4 is held by the chuck claws 77A by connecting screw faces of the chuck claws 77A in a threading manner to a distal end screw portion of the piston rod 4 extending outward thmugh the sealing member 6 of the hydraulic shock absorber 1. In the chuck device 77, the chuck claws 77A can be opened/dosed in cooperation with the inside guide 77B and the outside guide 77C (refer to Fig. 7(B)). Accordingly, the hydraulic shock absorber performance evaluation section 13 measures gas reaction force, damping force or the like of the hydraulic shock absorber 1 in a state where the sealing member 6 of the hydraulic shock absorber 1 has been mounted at the regular assembling position, thereby allowing hydraulic shock absorber performance evaluation.

The operation of the assembling apparatus 10 will be explained below.

(1) Setting of the hydraulic shock absorber 1 (Fig. 3) Oil is charged in the hydraulic shock absorber 1, and the hydraulic shock absorber 1, with the sealing member 6 temporarily fitted in the upper periphery of the outer tube 2 and the end plate 7 temporarily fitted therein, is conveyed to the clamp base 22 of the supporting section I I to be set in a standing manner. The clamp base 22 is moved upward by the clamp cylinder 23 and the upper portion of the outer tube 2 of the hydraulic shock absorber 1 is inserted into the gas injection portion 12 to be positioned at the gas injection work position.

-12 The vacuum head 32 is moved downward by the ascending/descending cylinder 36 and the end plate 7 of the hydraulic shock absorber 1 is pressed and held by the distal end portion of the vacuum head 32.

Air pressure is supplied to the lower air chamber 43B of the air injection head 31 (the upper air chamber 43A is opened to the atmosphere), the gas injection head 31 is moved downward about the vacuum head 32, and the upper portion of the outer tube 2 of the hydraulic shock absorber 1 is held by the distal end holding portion 3LA- At this time, the gas injection head 31 brings the inner periphery of the distal end holding portion 31A into dose contact with the upper and outer periphery of the outer tube 2 and brings the stepped portion 3 1B provided at the inner periphery of the distal end holding portion 31A into contact with the upper end face of the outer tube 2, so that the inner peripheral face of the outer tube 2 is made flush with a portion of the inner peripheral face of the gas injection head 31 positioned above the stepped portion 31B thereof.

(2) Measurement of a caulking margin (Fig. 4) A projecting amount of the upper end portion of the outer tube 2 to the end plate 7, which is a caulking margin H of the outer tube 2, is measured by using the level gauge 47 in a state where the hydraulic shock absorber 1 has been set by the damp base 22 of the supporting section 11, and the gas injection head 31 and the vacuum head 32 of the gas injection section 12 according to the above described (1), and a confa-mation (determination) is made whether or not the caulking margin H is in a predetermined value range.

The level gauge 47 measures the projecting amount of the upper end portion of the outer tube 2 to the end plate 7, namely the caulking margin H of -13the outer tube 2, in a state where the stepped portion 31B of the distal end holding portion 3 1A of the gas injection head 3 1 is brought into contact with the upper end face of the outer tube 2 and the distal end portion of the vacuum head 32 presses and holds the end plate 7, as described above.

(3) Injection of gas (Fig. 5) The vacuum head 32 is moved upward by the ascending/descending cylinder 36. The height of the ascending movement is set to a height where the distal end portion of the vacuum head 32 does not interfere with the sealing member 6 when the lower end of the sealing member 6 hfted up by vacuum suction force of the vacuum head 32 described later is positioned above the open end level of the vent passage 49 provided at the gas injection head 31 to the inner peripheral face of the gas injection head 31. Atthistime, as supplying of air pressure from the air supplying passage 45 of the vacuum head 32 to the lower air chamber 43B of the gas injection head 31 is continued, the gas injection head 31 still holds the upper end of the outer tube 2.

Vacuum suction force is applied to a space at the upper portion of the sealing member 6 temporanly fixed to the outer tube 2 of the hydraulic shock absorber I through the vacuum suction passage 53 of the vacuum head 32, the sealing member 6 and the end plate 7 are suctioned upward, and the seahng member 6 is lifted up above the upper end of the outer tube 2 and above the open end of the vent passage 49 on the inner peripheral face of the gas injection head 3 1.

Then, gas (such high pressure gas as nitrogen gas or the like) is injected into the gas chamber between the outer tube 2 and the inner tube 3 from the upper portion of the outer tube 2 held by the disW end holding portion 3 LA of the gas injection head 3 1, and thus the oil returning passage 8 formed in the rod guide 5, through the vent passage 49 of the gas injection -14head 3 1. When the pressure of the injected gas detected by a gas pressure gauge or the like provided at the vent passage 49 or the bke reaches a predetermined value, injection of gas is stopped- After gas has been injected into the upper portion of the outer tube 2, the vacuum head 32 is moved downward by the ascending/descending qdinder 36, so that the sealing member 6 and the end plate 7 are pressed on the upper end of the inner tube 3 within the outer tube 2 and held at the regular assembling position.

Dunng gas injectLon, the vacuum head 32 pushes the sealing member 6 up above the upper end of the outer tube 2 and thereafter the sealing member 6 is pressed down to the regular assembling position corresponding to the upper end of the inner tube 3, but the sealing lip of the sealing member 6 merely slides on the outer peripheral face of the piston rod 4 smoothly so that it is prevented from being damaged.

(4) Caulldng work on the hydraulic shock absorber (Fig. 6) Air pressure is supplied to the upper air chamber 43A of the gas injection head 31 (the lower air chamber 43B is opened to the atmosphere) and tJae gas injection head 31 is moved upward about the vacuum head 32, so that the upper portion of the outer tube 2 of the hydraulic shock absorber 1 -is released to the rollers 63 of the caulking device 33.

The damp base 22 is moved upward by the damp cylinder 23 to lift the hydraulic shock absorber 1 up to the caulking work position and to press the upper end face of the outer tube 2 on the roller faces of the respective rollers 63 in a state where the respective rollers 63 have been advanced to a position facing the upper end face of the outer tube 2 according to downward movement of the cam member 64 effected by the cam ascending/descending cylinder 65 and the pivoting body 6 1 has been rotated by the pivoting motor 62.

Thereby, a predetermined caulking load is applied to the upper end of the outer tube 2, the upper end of the outer tube 2 is deformed inwardly to form the upper end caulking portion 2A, and the sealing member 6 and the end plate 7 axe mounted at the regular assembling position of the upper end of the inner tube 3. At this time, the press load pressing the end plate 7 on the regular assembling position against the upper end of the inner tube 3 is, for example, 800 kgf, and the caulking load acting on the upper end of the outer tube 2 according to upward movement of the clamp base 22 effected by the damp cylinder 23 is, for example, 1200 kgE After the upper end caulking portion 2A is formed on the outer tube 2 the clamp base 22 is moved downward by the damp cylinder 23 so that the hydraulic shock absorber 1 is positioned at the performance evaluation work position. At the same time, rotation of the pivoting body 61 is stopped and the respective rollers 63 are moved back to the original position.

(5) Performance evaluation of the hydraulic shock absorber 1 When gas injection of the above described (3) is completed, the piston rod 4 of the hydraulic shock absorber 1 is pushed out. When the piston rod 4 is pushed out, the chuck device 77 of the performance evaluation section 13 automatically chucks the distal end portion of the piston rod 4. Then, the chuck device 77 is moved upward and downward according to upward and downward movements of the ascending/descending head 72 effected by the ascending/descending motor 73, and gas reaction force and damping force of the hydraulic shock absorber 1 are measured on the basis of forward/backward stroke of the piston rod 4 and an output value of the load gauge 7. 'Ihe gas reaction force is measured from an output value (static output value) of the load gauge 76 at each stroke cf the hydraulic shock absorber 1 under a low speed rotation of the motor 73. The damping force is -16measured by subtracting the gas reaction force from an output value (dyn output value) of the load gauge 7 at each stroke of the hydraulic shock absorber 1 under a high speed rotation of the motor 73.

The forward/backward stroke of the piston rod 4 at the performance evaluation time of the hydraulic shock absorber 1 is set to the maximum stroke, and thereby air mixed in oil in the oil chamber of the inner tube 3 is exhausted to the upper portion of the rod guide 5 and thus the gas chamber between the outer tube 2 and the inner tube 3 from the oil returning passage 8 of the rod guide 5.

Accordingly, the following effects are obtamed by use of the present embodiment.

(D The hydraulic shock absorber 1 is conveyed to the assembling apparatus10 in a state where the sealing member 6 has been temporarily fitted in the outer tube 2 of the hydraulic shock absorber 1, the sealing member 6 has been temporarily fitted is lifted up above the upper end of the outer tube 2 of the hydraulic shock absorber 1 to form a gas introducing passage to the hydraulic shock absorber 1, gas with the predetermined pressure is injected into the hydraulic shock absorber 1 via the gas introducing passage, and, after the gas injection, the sealing member 6 is mounted at the regular assembling position at the upper end of the inner tube 3 within the outer tube 2.

0 As the hydraulic shock absorber 1 is temporarily sealed by t1ae sealing member 6 in the course of conveyance of the hydraulic shock absorber 1 to the assembling apparatus 10 according to the above (1), there is no drawback that foreign matter enters into the hydraulic shock absorber 1, and management of parts can be facilitated.

(M In the above Q the sealing member 6 is lifted up above the upper end of the outer tube 2 smoothly by vacuum suction force of the vacuum head 32, or the sealing member 6 is pressed by the vacuum head 32, so that it can be held at the regular assembling position in the outer tube 2. Accordingly, the sealing hp of the sealing member 6 is prevented from being damaged and the assembling qual of the hydraulic shock absorber 1 can be improved.

(3) After the sealing member 6 is mounted at the regular assembling position within the assembling apparatus 10, then the piston rod 4 held by the chuck device 77 is moved upward and downward, so that performance of the hydraulic shock absorber 1 such as gas reaction force, damping force and the like can be evaluated.

As set forth above, the embodiment of the present invention has been explained in detail with reference to the drawings, but a specific structure of the present invention is not limited to dm embodiment. Modification or design or the like is included in the present invention without departing from the scope of the present invention.

MUSTRL4L APPIJCABII= As mentioned above, according to the present invention, an assembling quality of a hydraulic shock absorber can be improved while part management is facilitated without foreign matter entering into inside of the hydraulic shock absorber and without damage to a sealing member in the course of assembling the hydraulic shock absorber.

-18WHAT IS CIANEED IS:

1. A method of assembling a hydraulic shock absorber in which an oil storage chamber and a gas chamber above the oil storage chamber are formed between inner and outer tubes of the hydraulic shock absorber and upper portions of the inner and outer tubes are sealed by a sealing member, wherem an assembling apparatus is used, comprising a gas injection head which charges oil in the hydraulic shock absorber and holds an upper portion of an outer tube of the hydraulic shock absorber temporarily fitted in an upper inner peripheral portion of the outer tube with the sealing member and which has a vent path for injecting gas into the hydraulic shock absorber, a vacuum head in the gas injection head, which has a vacuum suction path for applying vacuum suction force in a space positioned above the sealing member temporarily mounted to the hydraulic shock absorber and which presses the sealing member on a regular assembling position at an upper end of the inner tube within the outer tube-, and a caulking device which is positioned outside the hydraulic shock absorber, which deforms an upper end of the outer tube inwardly to fix the sealing member at the regular assembling position, wherein the assembbng method comprising the steps of holding the upper portion of the outer tube of the hydraulic shock absorber by the gas injection head, liffing the sealing member temporarily mounted to the hydraulic shock absorber above the upper end of the outer tube by the vacuum suction force of the vacuum head, injecting gas with a predetermined pressure into the hydraulic shock absorber from the vent path of the gas injection head, pressing and holding the sealing member at the regular assembling position at the upper end of the inner tube by the vacuum head; moving the gas injection head above the upper portion of the outer tube; and deforming inwardly the upper end of the outer tube by the caullcing device to mount the sealing -19member at the regular assembling position.

2. An assembling apparatus for a hydraulic shock absorber in which an oil storage chamber and a gas chamber above the oil storage chamber are formed between inner and outer tubes of the hydraulic shock absorber and upper portions of the inner and outer tubes are sealed by a sealing member, the assembling apparatus comprising a gas injection head which charges oil in the hydraulic shock absorber and holds an upper portion of an outer tube of the hydraulic shock absorber temporarily fitted in an upper inner peripheral portion of the outer tube with the sealing member and which has a vent path for injectmg gas into the hydraulic shock absorber; a vacuum head in the gas injection head, which has a vacuum suction path for applying vacuum suction force in a space positioned above the sealing member temporarily mounted to the hydraulic shock absorber and which presses the sealing member on a regular assembling position at an upper end of the inner tube within the outer tube, and a caulking device which is positioned outside the hydraulic shock absorber, which deforms an upper end of the outer tube inwarc'Uy to fix the sealing member at the regular assembling position, wherein an upper portion of the outer tube of the hydraulic shock absorber is held by the gas injection head, the sealing member temporarily mounted to the hydraulic shock absorber is lifted above the upper end of the outer tube due to the vacuum suction force of the vacuum head, gas with a predetermined pressure is injected into the hydraulic shock absorber from the vent path of the gas injection head, the sealing member is pressed and held at the regular assembling position at the upper end of the inner tube by the vacuum head, the gas injection head is moved above the upper portion of the outer tube, and the upper end of the outer tube is deformed inwarcRy by the -20caulking device so that the sealing member can be mounted at the regular assembling position.

3. An assembling apparatus for a hydraulic shock absorber according to daim 2, comprising a rod holding device for holding a piston rod extending outward via the sealing member of the hydraulic shock absorber, wherein the rod holding device is driven upward and downward in a state where the sealing member of the hydraulic shock absorber is mounted at a regular assembling position, thereby allowing performance evaluation of the hydraulic 10 shock absorber.