CN1005354B - Sheet metal multi-groove V-belt pulley - Google Patents

Abstract

The sheet metal multi-groove belt pulley provided by the invention has the following characteristics: forming an integral piece with the cylindrical side wall from the circumference of the bottom surface; a multi-groove V-shaped pulley made of sheet metal and provided with a plurality of V-shaped grooves formed on the side wall at a specified interval; an annular curved portion concentric with the axis of the side wall and protruding toward the opening of the side wall is formed on the bottom surface of the belt pulley; absorbing high load from the plurality of V-belts by the bent portion; therefore, the strength of the belt pulley is improved, and the defects of material cost increase, difficult forming process, product weight increase and the like caused by blank thickness increase are avoided.

Description

Sheet metal system multiple-grooved Vee pulley V

The present invention relates to, spacing forms the sheet metal system multiple-grooved Vee pulley V of multiple tracks " V " shape groove in accordance with regulations on cup-shaped blank sidewall.

Existing in the past this sheet metal system multiple-grooved Vee pulley V, it is that the sheet metal material is shaped through deep drawn and reverse-drawing, form a cup-shaped blank that has bottom surface and sidewall to constitute, in accordance with regulations spacing forms several " V " shape groove, the sheet metal system multiple-grooved Vee pulley V of promptly so-called multiple tracks " V " shape groove on its sidewall.This belt pulley has dropped into commercialization production, and is used widely with the multiple-grooved Vee pulley V as the middle transmission of vehicle motor annex.

This sheet metal system multiple-grooved Vee pulley V is different with the foundry goods goods, and its advantage is: it is by processing such as thin-walled sheet metal blank drawn, spinning and make, so the weight of finished product is very little; And, has very high rotation merit transmission efficiency to the belt on wheel.Therefore, under high rotating speed, also can transmit the rotation merit exactly to v belt.In addition, the multiple v-belt on the sheet metal system mlultiple-groove sheave, its intensity also is significantly improved recently.Because the raising of multiple v-belt intensity, so, can not make the multiple v-belt fracture under quite high rotating speed even if the sheet metal system of making multiple-grooved Vee pulley V rotates yet.That is to say that in order to make multiple v-belt with high speed rotating, belt must be the high tensile strength winding with sheet metal system multiple-grooved Vee pulley V and cooperate, even but under this high tensile strength winding mated condition, rotate, multiple v-belt can not rupture yet.

As mentioned above, with high tensile strength the multiple v-belt winding is engaged on the sheet metal system multiple-grooved Vee pulley V, and when rotation, because of the multiple-grooved Vee pulley V is made with the thin-walled metal sheet, so produce plastic deformation at its sidewall, bottom surface or sidewall and bottom surface joint easily, thereby make this belt pulley be difficult to the needs of the raising of adaptation multiple v-belt intensity.

In this case, in order to prevent the distortion of sheet metal system multiple-grooved Vee pulley V, can use heavy-gauge sheeting to satisfy the raising of multiple v-belt intensity, but this will increase considerably Master Cost, on the other hand, if use heavy-gauge sheeting to make sheet metal system multiple-grooved Vee pulley V, its formation technique bothers very much, and its weight also will increase considerably, and it is a lot of that the result can make the advantage of sheet metal system multiple-grooved Vee pulley V reduce.

Sign in above-mentioned actual conditions, the object of the present invention is to provide a kind of can be easily and bearing is installed reliably, and can realize the sheet metal system multiple-grooved Vee pulley V of Bearing Installation automation.

In order to achieve the above object, the method for the sheet metal system multiple-grooved Vee pulley V employing that the present invention proposes is: on the bottom surface of cup-shaped blank, form one concentric and with the sidewall axis towards the toroidal bend part of the opening direction projection of sidewall.

This structure that the present invention proposes, on the multiple tracks on the sidewall that is rotating " V " shape groove, during big pressure of any period that the multiple v-belt that is subjected to cooperating with its winding applies, curved section becomes damper portion, can effectively this pressure be absorbed, and can be prevented the plastic deformation of sidewall, bottom surface or sidewall and bottom surface joint effectively.And, just form in the bottom surface one with the sidewall axis concentric, to the annular curved part of the projection of opening direction formation of sidewall.Therefore, simple in structure, make and also be not difficult, and can prevent shortcomings such as weight increase and cost increase effectively, so its effect is significant.

Accompanying drawing is represented, about the embodiment of sheet metal system multiple-grooved Vee pulley V of the present invention.Fig. 1 is a sectional drawing; Fig. 2 (a) to (j) is to each Main Stage machining state, Biao Shi half-sectional view in order between the finished product from sheet material; Fig. 3 (a1) represents the semi-section explanatory drawing of the concrete manufacturing process of above-listed manufacture method respectively to (j1); Fig. 4～Fig. 7 represents other embodiment's of the present invention half-sectional view.

2 ... * wall section

32 ... the bottom surface

46 ... curved section

100,100 ', 100 " ... several sheet metal system multiple-grooved Vee pulley Vs.

Below, by Fig. 1 one embodiment of the present of invention being described, 100 among the figure is for being equipped with the sheet metal system multiple-grooved Vee pulley V of bearing 91, and bottom surface 32 is linked to be an integral body with cylinder side wall 2 at circumferential part; Spacing forms " V " shape groove 61 in accordance with regulations on this sidewall 2; 32 the axial portions in the bottom forms a cylinder 42* who protrudes in the open part 22a side of sidewall 2, and the ring-type shaft shoulder 71 that extends internally with a leading edge becomes whole bearing telescoping part 31; After bearing 91 is pressed into bearing telescoping part 81.With cylinder 42 〈 ﹠﹠〉divide and to compress to axial portions, thus bearing 91 is flush-mounted in the bearing telescoping part 81.In addition, on bottom 32, form one concentric and with sidewall 2 to the toroidal bend part 46 of the direction projection of the open part 22a of sidewall 2.This curved section 46 has a kind of function of damper, absorbs pressure from the multiple v-belt (not shown) on many " V " shape grooves 61 on sidewall 2 with it.

Have an example of the sheet metal system multiple-grooved Vee pulley V manufacture method of bearing 91 below with reference to Fig. 2 and Fig. 3 explanation,

Fig. 2 (a) to (j) represents respectively, the sectional drawing of each Main Stage machining state from the sheet metal blank to finished product.

At first, the formation operation of the figure among Fig. 2 (a) expression cup-shaped blank: the sheet material of predetermined thickness is formed a cup-shaped blank 11 of being made up of the bottom surface 21 and the undressed sidewall 22 of open part 22a side band chimb 23 with the deep drawn method.

The formation operation of the oblique exponent part of Fig. 2 (b) expression: on above-mentioned cup-shaped blank 11 undressed sidewalls 22, form an oblique exponent part 31, undressed sidewall 22 is divided into multiple tracks " V " the shape groove shaped portion 24 of opening 22a side, with the preliminary forming part 25 of bottom surface 21 sides.Thereby draw cup-shaped blank 12 with oblique rank.

The formation operation of the undressed preliminary forming blank of Fig. 2 (C) expression: the preliminary forming part 25 of the cup-shaped blank 12 on the oblique rank of above-mentioned band, with bottom surface 21, be shaped through reverse-drawing, anti-to the inside Zhe once, make between oblique exponent part 31 and the preliminary forming part 25, form the outwards convex portion 41 of outstanding inside anti-Zhe, divide 42 preliminary forming part 25 as bearing support, bottom surface 21 is turn-over base plate 43, thereby makes undressed preliminary forming blank 13a.

Fig. 2 (d) expression forms the cylindrical bulge and divides 44 and the formation operation of the preliminary forming blank of convex portion 45.Divide 42 and turn-over base plate 43 bearing support of undressed preliminary forming blank 13a, carrying out a reverse-drawing more to the inside is shaped, between " V " shape groove shaped portion 24 and oblique exponent part 31, form an anti-Zhe convex portion 44 of cylindrical side that outwards protrudes equally.

Meanwhile, bearing support divide 42 and multiple tracks " V " shape groove shaped portion 2* between bottom surface 32, through deep drawn processing, form a bandy convex portion 4*.

The preparation of Fig. 2 (e) expression wall thickening forms operation, chimb 23 cylindrical turnings of the preformed blank 13 that the formation operation at above-mentioned preformed blank is obtained and remove after, end 24a in anti-Zhe convex portion 44 sides of cylindrical, be retained under the state at multiple tracks " V " shape groove forming section 24 places, make multiple tracks " V " shape groove shaped portion 24, the amount that outwardly-bent wall thickening is required as wall thickening convex camber 51, thereby is made undressed wall thickening shaping blank 14a.

Fig. 2 (f) expression wall thickening forms operation: the wall thickening convex camber 51 of undressed wall thickening shaping blank 14a is flattened, form one and the corresponding heavy wall multiple tracks of its degree of crook " V " shape groove shaped portion 52, simultaneously in a part that approaches end 24a, form the standard cell of preparing for shaping multiple tracks " V " shape groove together 62, thereby make wall thickening shaping blank 14.

The formation operation of Fig. 2 (g) expression multiple tracks " V " shape groove: to multiple tracks " V " the shape groove forming section 52 of wall thickening shaping blank 14, with standard cell 62 is the shaping standard point, be respectively equipped with high platform 63,64 at the anti-Zhe convex portion 44 of cylindrical side with edge of opening 22b both sides, form a plurality of " V " shape grooves 61 side by side, thereby make the blank 15 that has multiple tracks " V " shape groove.

Fig. 2 (h) expression curved part forms operation: convex portion 45 is inwardly carried out reverse-drawing, form the curved part 46 to the protruding drum of direction of the open part 22a of multiple tracks " V " shape groove shaped portion 52 on bottom surface 32, form blank 16 thereby make curved part.

Fig. 2 (i) expression bearing support forms operation: the excision of the core of the base plate 43 of reverse side, by cylinder 42 ' and the ring-type shaft shoulder 71 form bearing setting-in part 81, so just form a bearing support blank 17.

Being pressed into and fastening operation of Fig. 2 (j) expression bearing: with finished product bearing 91 embed bearing supports form the cylinder 42 of the bearing telescoping part 81 on the blanks 17 ' in, till compressing, and bearing is in addition fastening with the shaft shoulder 71.

Indication by above-mentioned each procedure is processed, just can make desired sheet metal system multiple-grooved Vee pulley V 100, be characterized in, have multiple tracks " V " shape groove 61 on the sidewall, on base plate 32, form a curved section 46, and be embedded with bearing 91 in axial portions towards the protruding drum of open part 22a direction.

Fig. 3 (a1) to (j1) is the sectional drawing to the concrete manufacturing process of same manufacture method of above-mentioned sheet metal system multiple-grooved Vee pulley V 100, being described in detail as follows of each procedure.

(1) operation (Fig. 2 (a)) of manufacturing cup-shaped blank

The manufacturing process of this cup-shaped blank is shown in Fig. 3 (a1), with the sheet material of predetermined thickness and external diameter as moulding material, with that move and fixing inside and outside two stretching dies 111,112 and pressure die 113, the material deep drawn is shaped to the outside dimension and the degree of depth of regulation, forms a cup-shaped blank 11 that constitutes by bottom surface 21 and undressed sidewall 22.At this moment, in the opening portion edge of undressed sidewall 22, leave the chimb 23 of the excess stock formation of stretch forming generation.

(2) tiltedly rank form operation (Fig. 2 (b))

The formation operation on these oblique rank is shown in Fig. 3 (b1), cup-shaped blank 11, chimeric with remain under the state on the interior pressure die 211,212 that overlaps, with precompressed rank roller 213, part to the undressed sidewall 22 of cup-shaped blank 11 bottom surfaces 21 sides is carried out pre-spinning, at this partially-formed oblique exponent part 31, make cup-shaped blank 12 with oblique rank.

In this procedure, last on the undressed side wall portion 22 of cup-shaped blank 11, form an oblique exponent part 31, oblique thus exponent part 31 is this undressed sidewall 22, be divided into multiple tracks " V " the shape groove shaped portion 24 that is positioned at through open part 22a one side in wealthy footpath, and be positioned at the preparation shaped portion 25 of diameter less than the former bottom surface 21 1 sides.

(3) operation (Fig. 2 (C)) of the undressed preliminary forming blank of manufacturing

The operation of this is undressed preliminary forming blank, shown in Fig. 3 (C1), the cup-shaped blank 12 on the oblique rank of above-mentioned band, chimeric with remain on coincide together each in pressure die 311, on 312, with in-draw mould 313, this preparation shaped portion 25 and bottom surface 21 with the cup-shaped blank 12 on oblique rank, reverse-drawing is shaped to the internal diameter size and the degree of depth of regulation, anti-to the inside Zhe between oblique exponent part 31 and preparation shaped portion 25, forms the outwards convex portion 41 of the outstanding anti-Zhe of inside circle, form bearing support by preparation shaped portion 25 and divide 42, form turn-over base plate 43 by base plate 21.

In this procedure, at last oblique exponent part 31 is given to turn over preparation shaped portion 25 to be configured as acute angle.In polarizers of big angle scope like this, carry out in the reverse-drawing shaping, big internal stress can take place on material, but here dare to be the convex portion 41 of outwards giving prominence to, inwardly justify anti-Zhe, form acute angle-shaped curved section, this is because bend to that acute angle is the easiest goes out this internal stress loss, but also has a kind of damping function, and can be with the stress concentration that the produced convex camber 41 at this anti-Zhe, therefore, can make its shaping reach more highi degree of accuracy and carry out easily.

(4) operation (Fig. 2 (d)) of manufacturing preformed blank

The operation of making this preformed blank is as follows.Make oblique exponent part 31 sides form the interior pressure die 312 of ring-shaped protrusion 312a, and oblique exponent part 31 sides are formed between the in-draw mould 313 of ring-type reentrant part 313a, chimeric with keeping under the state with oblique rank cup-shaped blank 13a, make the rotation of in-draw mould 313 limits, the limit extruding, shown in Fig. 3 (d1), at multiple tracks " V " shape groove shaped portion 24 and tiltedly between the exponent part 31, form outwards give prominence to identical with above-mentioned situation, projection 44 to the anti-Zhe of cylindrical, simultaneously also at the convex camber 41 of two anti-Zhe, on the bottom surface 32 between 44, form a convex portion 45, so just make preformed blank 13.

In this procedure, the convex portion 41 that had been drawn as the acute angle-shaped anti-Zhe of inside circle in the preceding one procedure once, after pressing off again, form convex portion 45 with projection 44 to the anti-Zhe of cylindrical, so concentrate on the inwardly residual stress at convex camber 41 places of the anti-Zhe of circle, disperse rightly and be released in convex part divide 45 and the convex camber 44 of anti-Zhe on, the coupling of shaping each several part is good, can not influence high-precision shaping.

(5) wall thickening forms operation (Fig. 2 (e)) in advance

This wall thickening forms operation in advance, shown in Fig. 3 (e1), with external compression mould 41* and the interior pressing mold 412 that reproduces preformed blank 13 inner surface configurations, under the state of inside and outside maintenance preformed blank 13, cut off multiple tracks " V " shape groove shaped portion 24 with shearing roller 413 size positions in accordance with regulations, chimb 23 and excess stock part are removed earlier, 〈 ﹠﹠〉shown in Fig. 3 (e2), in it is clamped in one heart, external compression mould 414 and 415, between 416, simultaneously end 24a tightly is clamped in and reproduces in the preformed blank 13, in the external surface shape, external compression mould 415, under the state between 416, with outer deep drawn forming die 417, the outside circular direction bending forming of amount of multiple tracks " V " shape groove shaped portion 24 wall thickenings needs, form wall thickening projection 51, so just made undressed wall thickening shaping blank 14a.

(6) the formation operation of wall thickening (Fig. 1 (f))

This wall thickening forms operation, shown in Fig. 3 (f1), undressed wall thickening shaping blank 14a is inlaid on the preforming mould 511, use simultaneously external compression mould 512 with the outside with one heart clamping the projection 41 of the projection 45 of blank 14a, the anti-Zhe of interior circle, bearing support divides 42 and various piece such as turn-over base plate 43.About the part 51 that above-mentioned wall thickening bloats, its open end edge 22b is blocked and is supported on the scalariform retaining platform part 511a of preforming mould 51*.

In this state, multiple tracks " V " shape groove preforming roller 513 with double as wall thickening roller, the protruding end part of the protrusion of wall thickening projection 51 is pushed, but because of the edge of opening part 22b of wall thickening convex camber 51 is being kept off and is being supported in a grade platform 〈 ﹠﹠〉on, roll-in face 513a by this roller 513, wall thickening convex camber 51 is crushed gradually, the generation plastic flow is shaped, and reach the heavy wall of predetermined thickness in this part, depend on the standing shape forming face 513b of same roller 513 simultaneously, wall thickening projection 51 and become near the outside anti-Zhe projection 44 of multiple tracks " V " shape groove forming section 52 of heavy wall end 24a, usually carry out spinning from the inside roll compacting of cylindrical, form the standard cell of using when being shaped multiple tracks " V " shape groove together in this section 62 earlier, so just made wall thickening shaping blank 14.

In this case, to multiple tracks " V " shape groove forming section 5 〈 ﹠﹠〉part 44, and absorbed internal stress effectively, make unlikely other shaped portion that relates to of this stress influence.

(7) multiple tracks " V " shape groove forms operation (Fig. 2 (g))

The manufacturing process of multiple tracks " V " shape groove, as Fig. 3 (g1) with (g2), as follows about above-mentioned preforming mould 511: that this cover combination is replaced with the 1st and the 2nd eccentric multiple tracks " V " shape groove preforming mould 515 successively with the combined method of forming rolls 513,517, with forming rolls 516,518, under the also the same clamp position with above-mentioned situation, standard cell 62 is used as the shaping standard point that shaping multiple tracks " V " shape groove is used, this multiple tracks " V " shape groove shaped portion 52 is carried out the 1st, the 2nd pre-spinning, gradually carry out roll extrusion, make each a plurality of preforming multiple tracks " V " shape groove 61a side by side, 61b, move closer to the size and shape of regulation, in anti-Zhe bump 44 1 sides of cylindrical side and edge of opening 22b one side, be formed separately the projection ear portions 63 of projection gradually simultaneously, 64.

That is to say, for the multiple tracks that becomes heavy wall " V " the shape groove shaped portion 52 here, 62 one-tenth of standard cell are the shaping standard point of multiple tracks " V " shape groove shaping usefulness for this reason, simultaneously again because of the existence of the anti-Zhe convex camber 44 of cylindrical is arranged, has absorbed internal stress effectively, therefore, in the 1st, the 2 the pre-spinning, can be with a plurality of grooves of preforming multiple tracks " V " shape groove 61a, 61b, all to claim and qualified wall thickness and size and dimension layout, easily shaping side by side accurately.

After this, shown in Fig. 3 (g3), the combination of multiple tracks " V " shape groove forming die and forming rolls, be replaced by the combination of eccentric multiple tracks " V " shape groove polishing forming die 519 and multiple tracks " V " shape groove press polish forming rolls 520, here, also under the clamp position identical with above-mentioned situation, with " V " shape groove polishing roller 520, a plurality of side by side preforming multiple tracks " V " shape groove 61b through above-mentioned the 2nd pre-spinning, inwardly roll deeply from cylindrical and to carry out the polishing spinning, for this multiple tracks " V " shape groove shaped portion 62, can so just make the blank 15 of band multiple tracks " V " shape groove with highi degree of accuracy a plurality of side by side multiple tracks " V " shape groove 61 that is shaped.

In being shaped in this section, when the pre-spinning of this multiple tracks " V " shape groove 61 and polishing spinning, because the anti-Zhe convex camber 44 of cylindrical is arranged, also has the convex convex camber 45 that outwards bloats of part connection therewith, and absorbed the delicate effect of internal stress effectively, stoped the influence of shaping stress and residual stress to other shapings.

(8) curved section forms operation (Fig. 2 (h))

Form in the operation, at this curved section the above-mentioned blank 15 that has multiple tracks " V " shape groove.Show as Fig. 3 (h1), in being inlaid in pressure die 611 time, with multiple tracks " V " the shape groove 61 of pressure die 612 from outer maintenance blank 15.

Then, make reverse-drawing roller 613 rotation on one side, on one side above-mentioned convex portion 45 is carried out reverse-drawing processing, make this convex portion 45 form the curved section 46 that protrudes to open part 22a direction, form blank 16 to make curved section.

When forming curved section 46, also be because interior anti-Zhe projection 41 of circle and the anti-Zhe projection 44 of cylindrical are arranged, and absorbed the delicate effect of internal stress effectively, stoped the influence of shaping stress and residual stress to other shaped portions.

(9) bearing part forms operation (Fig. 2 (i))

Bearing part forms operation, at first shown in Fig. 3 (i1), above-mentioned curved section is formed part 16, with interior pressure die 614,615 and tightly clamping of external compression mould 616, divide 42 with shaping roller 617 with the bearing support that curved part forms blank 16, first shaping is once carried out the correction of size and precision again.

Also be that the internal stress that applies during well shaping has absorbed by anti-Zhe projection 41 of interior circle and curved section 46 this moment.

Secondly, shown in Fig. 3 (i2), with other interior pressure die 618 and external compression mould 619, curved section is formed the turn-over base plate that is connected with curved section 46 43 surrounding edges 71 of blank 16, under powerful clamp position, wash out the core of turn-over base plate 43 with blanking die 620, keep its peripheral part 71, form a bearing telescoping part 81 of forming by the cylindrical portions may 42 and the ring-type shaft shoulder by this technology, so just made bearing support and formed part 17.

(10) bearing is pressed into and fastening operation (Fig. 2 (i)).

Bearing is pressed into and fastening operation, shown in Fig. 3 (j1), at first, with interior pressure die 711 and external compression mould 712, bearing support is formed the curved section 46 of part 17, the same with said method, in the time of powerful clamping, with the protruding terminus 711a of pressure die 711 in same with cylinder 42 ' cylindrical bottom withstand, with interior pressure die 713 the ring-type shaft shoulder 71 is held on again, under this state, with being pressed into mould 714, finished product bearing 91 be pressed into the cylinder 42 that constitutes bearing telescoping part 81 ' within, till pushing up the shaft shoulder 71, and with cylinder 42 ' cylindrical top 42 ", compress setting-in.

Bearing be pressed into fastening operation in, just the protruding terminus 711a by interior pressure die 711 withstands cylinder 42 ' cylindrical bottom own, and with interior pressure die 713 shaft shoulder 71 is supported, so make being pressed into of finished product bearing 91 very well and easy with fastening work.

Process by above-mentioned each procedure, just can highi degree of accuracy to make present embodiment desired, on sidewall 2, has multiple tracks " V " shape groove 61, on bottom surface 32, have towards the toroidal bend part 46 of sidewall 2 open part 22a direction projectioies, and 32 axial portions setting-in the sheet metal system Vee pulley V 100 of bearing 91 in the bottom surface.

In addition, curved section not necessarily is only limited to this a kind of section shape of pointing out among the embodiment, the convex shape towards the recessed mitigation of open part 22a direction that curved section 46 ' also can be is shown in Figure 4.

When forming curved section, the fixation the foregoing description that also differs is such, earlier make a convex portion in the direction opposite with open part 22a, carrying out reverse-drawing then, make it form projection towards opening 22a direction, for example, it also is fine towards the direction projection of open part 22a.

In addition, sheet metal system multiple-grooved Vee pulley V of the present invention is not limited to the sheet metal system multiple-grooved Vee pulley V of pointing out in the foregoing description that bearing is housed, and for example, does not have the sheet metal system multiple-grooved Vee pulley V of setting-in bearing; Or as shown in Figure 5, the sheet metal system multiple-grooved Vee pulley V of bottom surface 32 ' band stage also can.

The present invention also can make the sheet metal system multiple-grooved Vee pulley V of different types in actual applications.As shown in Figure 6, the internal surface of sidewall 2 not the sheet metal system multiple-grooved Vee pulley V 100 of the smooth inwall of trough of belt (or recessed portion) '; Or as shown in Figure 7, on the internal surface of sidewall 2, form the position of several roads, parallel distribution along the circumferential direction, the sheet metal system multiple-grooved Vee pulley V 100 of " V " shape ring-type inside groove 35 littler " than above-mentioned multiple tracks " V " shape groove size corresponding to top, cylindrical multiple tracks " V " shape groove 61 ridges.

Claims (1)

1, a kind of sheet metal system multiple-grooved Vee pulley V, its bottom surface circumference and cylindrical lateral wall are linked to be a single piece, in accordance with regulations spacing forms multiple tracks " V " shape groove on above-mentioned sidewall, its feature is in axial portions in above-mentioned bottom surface, integrally form cylindrical portions may and shaft shoulder part, above-mentioned cylindrical portions may is side-prominent to the open part of sidewall, be pressed into bearing and make it chimeric, and carry out fastening to bearing, above-mentioned shaft shoulder part from the tip edge part of above-mentioned cylinder outstanding to the inside be pressed into above-mentioned cylinder in also chimeric bearing contact, simultaneously, on the bottom surface between above-mentioned cylinder and the above-mentioned sidewall, form concentric with the sidewall axis, and towards the toroidal bend part of sidewall opening part side drum.

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