Jig for press-fitting divided sealing ring

In a jig for press-fitting a divided sealing ring, while a sleeve is attached to a first rod head, a guide region leading to a recess is defined between an inner circumferential surface of the sleeve and a rod. When a divided sealing ring attached to an outer circumferential surface of the rod is press-fitted to a prescribed position in the recess by passing the divided sealing ring through the guide region by using a plunger, positioning engagement regions engaged with each other are provided between the sleeve and the plunger.

TECHNICAL FIELD

This invention relates to a structure of a jig for press-fitting a divided sealing ring.

BACKGROUND ART

A sealing ring is used for preventing leakage of oil in a hydraulic elevator jack, a hydraulic cylinder, and other fluid transmission apparatuses. The sealing ring is formed from an annular member, and such a structure that a part in a circumferential direction is cut and opposing end surfaces abut on each other is adopted.

By using such a divided sealing ring, the sealing ring can be replaced without disassembling a fluid transmission apparatus. Therefore, the number of man-hours and cost for maintenance of the fluid transmission apparatus can be reduced.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

In selling such divided sealing rings, a divided sealing ring alone is sold. Proper attachment of a divided sealing ring to an annular groove provided in a rod head requires difficult operations, however, no specific measures for facilitating the operations have not been studied so far.

An object of this invention is to solve the problem above and to provide a jig for press-fitting a divided sealing ring which can achieve improved operation efficiency in proper attachment of a divided sealing ring to an annular groove provided in a rod head.

Solution to Problem

A jig for press-fitting a divided sealing ring is used in attaching an annular divided sealing ring to a rod head, the rod head having therein an annular groove recessed radially outward and provided in a cylindrical inner circumferential wall extending in an axial direction of a rod, and it includes features below.

The rod head includes at least a first rod head and a second rod head, and the annular groove is defined by combination of a projection provided in the second rod head with a recess provided in the first rod head.

The jig for press-fitting a divided sealing ring includes, with the first rod head and the second rod head being separated from each other along the axial direction of the rod, a sleeve attached to a second rod head side of the first rod head and a plunger attached to a surface of the rod between the first rod head and the second rod head.

While the sleeve is attached to the first rod head, a guide region leading to the recess is defined between an inner circumferential surface of the sleeve and the rod, and when the divided sealing ring attached to an outer circumferential surface of the rod is press-fitted to a prescribed position in the recess by passing the divided sealing ring through the guide region by using the plunger, positioning engagement regions engaged with each other are provided between the sleeve and the plunger.

In another form, the sleeve is divided into a plurality of parts with respect to an outer circumference of the rod and the plunger is divided into a plurality of parts with respect to the outer circumference of the rod.

In another form, a bolt through hole for fixing the second rod head to the first rod head is provided in the first rod head, and the sleeve is attached to the first rod head by using the bolt through hole.

In another form, in the guide region, a distance between the inner circumferential surface of the sleeve and the outer circumferential surface of the rod is set to gradually decrease toward the recess.

Advantageous Effects of Invention

According to the jig for press-fitting a divided sealing ring, operation efficiency in proper attachment of a divided sealing ring to an annular groove provided in a rod head can be improved.

DESCRIPTION OF EMBODIMENTS

A jig for press-fatting a divided sealing ring in an embodiment based on the present invention will be described hereinafter with reference to the drawings. When the number or an amount is mentioned in an embodiment described below, the scope of the present invention is not necessarily limited to the number or the amount unless otherwise specified. The same or corresponding elements have the same reference numeral allotted and redundant description may not be repeated.

Arrangement of Rod, Rod Head, and Divided Sealing Ring

Arrangement of a rod100, a rod head200, and a divided sealing ring400will be described with reference toFIG. 1.FIG. 1is a vertical cross-sectional view showing arrangement of rod100, rod head200, and divided sealing ring400.

Rod head200is provided on an outer circumferential surface of columnar rod100. Rod head200includes therein, an annular groove200grecessed radially outward and provided in a cylindrical inner circumferential wall extending in an axial direction of rod100. Rod head200includes a first rod head201, a second rod head202, and a third rod head203. A bolt through hole201his provided in first rod head201and a bolt fastening female thread203his provided in third rod head203. Second rod head202is fastened as being sandwiched between first rod head201and third rod head203with the use of a fastening bolt B1.

In the present embodiment, a first sealing ring410and a second sealing ring420are included as divided sealing ring400. Annular groove200gis defined by combination of a projection202bprovided in second rod head202with a recess201aprovided in first rod head201. Divided sealing ring400is attached to annular groove200gby press-fitting.

Jig for Press-Fitting Divided Sealing Ring

A jig for press-fitting a divided sealing ring will be described with reference toFIGS. 2 to 8.FIGS. 2 and 3are a developed plan view and a developed front view showing a structure of a sleeve600, respectively,FIG. 4is a partially enlarged view of a region shown with IV inFIG. 3,FIGS. 5 and 6are a developed plan view and a developed front view showing a structure of a plunger700, respectively,FIG. 7is a cross-sectional view along the line VII-VII inFIG. 6, andFIG. 8is a plan view showing advantages of plunger700. The jig for press-fitting a divided sealing ring in the present embodiment includes sleeve600and plunger700.

Referring toFIG. 2, sleeve600includes two semicircular divided sleeves610resulting from division into two parts on a circumference. Two divided sleeves610are coupled to each other by an elastic piece600c. Sleeve600is made of a material such as MC nylon and shaped.

A hole for bolt passage630and an engagement protrusion640are provided in each divided sleeve610. Hole for bolt passage630is provided in divided sleeve610at a position at approximately 90 degrees, and engagement protrusions640are provided in divided sleeve610at positions at approximately 30 degrees and 150 degrees. On an end surface of divided sleeve610, a coupling recess670is provided in one divided sleeve610, and a coupling protrusion680is provided in the other divided sleeve610. Annular sleeve600is maintained by coupling coupling recess670and coupling protrusion650to each other.

Referring toFIGS. 3 and 4, a first plane610ain parallel to a surface of rod100, a first inclined surface610t1inclined radially outward from first plane610a, a second plane610bwhich extends from first inclined surface610t1in parallel to the surface of rod100, a second inclined surface610t2inclined outward from second plane610b, and an arc face600precessed radially outward from second inclined surface610t2like an are are provided in an inner circumferential surface of divided sleeve610on a side of rod100, when viewed from a side where engagement protrusion640is provided.

An engagement tab650is provided at an end portion of one divided sleeve610, and an engagement hole660is provided at an end portion of the other divided sleeve610. In attaching divided sleeve610to rod100, sleeve600can readily be fixed to an outer circumferential surface of rod100by engaging engagement tab650with engagement hole660.

Though an example in which sleeve600is constituted of two divided sleeves610is described in the present embodiment, the number of divided parts is not particularly restricted so long as the number is two or more.

Referring toFIGS. 5 and 6, plunger700includes four arc-shaped divided plungers710resulting from division into four parts on the circumference. Four divided plungers710are coupled to one another by an elastic piece700c. Plunger700is made of a material such as MC nylon and shaped.

Referring toFIG. 7, an inner circumferential surface of divided plunger710in contact with rod100is a flat surface710p. An outer circumferential surface includes a first outer circumferential surface711, a second outer circumferential surface712smaller than first outer circumferential surface711in a direction of radius, and a third outer circumferential surface713further smaller than second outer circumferential surface712in the direction of radius. A protruding portion714which protrudes radially outward is provided below third outer circumferential surface713, and a fourth outer circumferential surface715recessed in the direction of radius is provided below protruding portion714.

A distance (H1) from a surface of rod100to protruding portion714is set to be substantially equal to a distance (H2, seeFIG. 9) from the surface of rod100to a bottom surface (600p) of arc face600pwhile sleeve600is attached to first rod head201and a divided sealing ring which will be described later is attached.

In plunger700, as shown inFIGS. 5 and 6, divided plungers710are coupled by elastic piece700c. Consequently, when plunger700is attached to rod100with elastic piece700cbeing folded as shown inFIG. 8, rod100has a diameter, for example, of ϕ125. In contrast, when plunger700is attached to rod100with elastic piece700cbeing extended, rod100has a diameter, for example, of ϕ160. A single plunger700can thus be adapted to rods of a plurality of diameters.

Though an example in which plunger700is constituted of four divided plungers710is described in the present embodiment, the number of divided parts is not particularly restricted so long as the number is two or more.

A procedure of press-fitting divided sealing ring400to rod head200with the use of the jig for press-fitting a divided sealing ring in the present embodiment will be described with reference toFIGS. 9 and 10.

Referring toFIG. 9, in replacing divided sealing ring400, rod head200is separated into first rod head201, and second rod head202and third rod head203. Then, sleeve600is attached to first rod head201. In attaching sleeve600to first rod head201, engagement protrusion640provided in sleeve600is inserted in bolt through hole201hin first rod head201.

While sleeve600is attached to first rod head201, a guide region G1leading to recess201ais defined between the inner circumferential surface of sleeve600and rod100.

Divided sealing ring400is attached to the outer circumferential surface of rod100in the vicinity of sleeve600. Positioning of divided sealing ring400does not particularly give rise to a problem.

Plunger700is fixed to the outer circumferential surface of rod100exposed between first rod head201and second rod head202.

Referring toFIG. 10, plunger700is moved toward first rod head201(in a direction shown with an arrow F inFIG. 10). Divided sealing ring400is also moved by being pushed by plunger700, and divided sealing ring400is fitted into recess201aprovided in first rod head201.

A distance D from an upper end surface of recess201ato arc face600pprovided in sleeve600is determined to be equal to a total dimension of a width D1of divided sealing ring400and a distance D2from an upper end surface of plunger700to protruding portion714.

Consequently, press-fitting of divided sealing ring400to a proper position in recess201aprovided in first rod head201can be checked by checking fitting of protruding portion714to arc face600p(engagement of protruding portion714with arc face600pwhen plunger700is moved toward first rod head201. Arc face600pand protruding portion714define a positioning engagement region.

A distance to arc face600pmeans a distance to a most recessed point in arc face600pand a distance to protruding portion714means a distance to a most protruding point of protruding portion714.

In press-fitting divided sealing ring400into recess201a, second inclined surface610t2, second plane610b, first inclined surface610t1, and first plane610aare provided in the inner circumferential surface of sleeve600such that an inner diameter gradually decreases as shown inFIG. 4. Thus, in guide region G1, a distance between the inner circumferential surface of sleeve600and the outer circumferential surface of rod100gradually decreases toward recess201ain the inner circumferential surface of sleeve600. Therefore, press-fitting of divided sealing ring400into recess201acan be facilitated.

Thereafter, the structure shown inFIG. 1is obtained by removing sleeve600and plunger700and fastening first rod head201and second rod head202by using fastening bolt B1.

According to the jig for press-fitting a divided sealing ring in the present embodiment, divided sealing ring400can readily be press-fitted to a prescribed position by using sleeve600and plunger700.

REFERENCE SIGNS LIST