US3044412A - High pressure hydraulic pump or motor - Google Patents

Description

July 17, 1962 E. ORSHANSKY, JR 3,044,4

HIGH PRESSURE HYDRAULIC PUMP OR MOTOR Filed May 15. 1958 4 Sheets-Sheet 1 I m rm mm m NJ w mi W 7 m A WNI H!1%% m 0 Q00 w 1 W M w Z $13 1 N I V e E -i v 4 L w w ww mm w I N mm T m mmwm Q9? 7 A j mm &\ NM. QM NM y 1962 E. ORSHANSKY, JR 3,044,412

HIGH PRESSURE HYDRAULIC PUMP 0R MOTOR Filed May 13. 1958 4 Sheets-Sheet 2 1 ara/M11 INVENTOR. .lf/xas' 06.5297/1/56'44 J22.

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HIGH PRESSURE HYDRAULIC PUMP OR MOTOR Filed May 13, 1958 4 Sheets-Sheet 3 INVENTOR. .52: Olav/max la.

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New York Air Brake Company, a corporation of New Jersey Filed May 13, 1958, Ser. No. 734,869 6 Claims. (Cl. 103-161) This invention relates to hydraulic apparatus of the radial piston type, capable of utilization either as a pump or motor.

Apparatus of this character is extensively installed in aircraft, and it is highly advantageous to use high pressures for the liquid so as to economize onspace and Weight. Such high pressures are of the order of several thousand pounds per square inch. In utilizing such high pressure, stresses and strains are imposed upon the cylinder block with which the pistons are associated. Forces of relatively high magnitude tending to misalign the nonrotary valve elements with respect to the block are also created. Unless special precautions are taken to reduce or eliminate the effect of these undesired forces, such as the provision of sturdy thrust bearings for-the cylinder block, the hydraulic apparatus operates at greatly reduced efficiency, and with undue and rapid wear.

It is one of the objects of this invention to improve and simplify apparatus of this character, whereby these disadvantages are adequately overcome, and particularly to make it possible to relieve the bearings of hydraulic thrust.

In order to accomplish this result, the cylinder block structure is made in two parts axially spaced along the axis of rotation, and a non-rotary valve plate is placed between the blocks, cooperating with both of them. The hydraulic thrust, due to the high pressures, urging the blocks apart is sustained by abutments carried on the shaft upon which the blocks are mounted. Furthermore, the shaft carrying the blocks is subjected to a tensioning force by this means, and this shaft can easily sustain such a load without special provisions.

It is another object of this invention to simplify the valving function of the apparatus. This is rendered possible by the provision of the non-rotary center valve plate.

It is another object of this invention to reduce or substantially neutralize the forces or torques that would tend to cock the cylinder blocks. These forces are those existing between the center valve plate and the cooperating rotary plates, and created by the pressures that predominate, produced by the liquid in the cooperating ports. By the aid of a center valve plate, and because of the arrange ment of the bearings for the shaft carrying the blocks, the torques produced by these pressures are quite well neutralized. i

This invention possesses many other advantages, and, has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming a part of the present specification. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal sectional view of an apparatus incorporating the invention;

FIGS. 2, 3 and 4 are cross-sectional views taken respectively along the planes corresponding to lines 2-2, 3-3 and 4-4 of FIG. 1;

FIG. 5 is a diagrammatic view of the structure, for illustrating the manner in which the bearings for the shaft are 3,044,412 Patented July 17, 1962' relieved or thrust forces, and in which the cocking torques are neutralized; and

FIG. 6 is a fragmentary sectional view showing details of the cylinder block and of a piston movable therein.

The apparatus has a main axis 1 (FIGS. 1', 2, 3 and 4). This axis corresponds to the axis of'revolution of a pair of axially spaced blocks 2 and 3. Each cylinder block comprises a structure split by a plane normal to axis 1 to provide two sections 2a, 2b or 3a, 3b. Each pair of sections 2a, 2b and 3a, 3b are joined together, as by a plurality of fillister head machine screws 4 (FIGS. 1 and 3). The pairs of sections 2a, 2b and 3a, 312 have plane contacting surfaces 5 and 6 (FIG. 1). Each block 2 and 3 has a through central bore which serves to mount the blocks on a shaft 7. Keys 8 and 9 respectively couple the shaft 7 to the blocks 2 and 3. The block 3 is arranged to abut a shoulder 7a formed on shaft 7. The central bore of this block is smaller than that of block 2, to fit that portion 711 of the shaft 7 which is reduced to define shoulder 7a.

By proving the shoudder 7a, a thrust toward the left on block 3 is not communicated to the other elements mounted on shaft 7. M

Each block 2 and 3, with the associated pistons as hereinafter described, and the cooperating means for reciprocating the pistons, are quite similar in structure to that disclosed in a prior application filed on September 24, 1956, in the name of Elias Orshansky, Jr., under Serial No. 611,645, now abandoned, and entitled Hydraulic Pump or Motor. a

Each of the sections 2a, 2b, 3a, 3b is provided with a plurality of cylinder bores 11 radial to the axis 1 (FIGS. 1 and 3) and equiangularly spaced about said axis. The axes of the bores in each of the sections all lie in a plane which is transverse to the axis of rotation 1, and these planes are spaced apart along axis 1. J

In the present instance, there are seven bores in each block section 2a, 2b, 3a, 3b, and the bores are angularly aligned as indicated most clearly in FIGS. 1 and 3. Thus the bores in each block are arranged in pairs, the bores of each pair being parallel and spaced along axis 1, and the corresponding pairs of bores in blocks 2, 3 are also parallel with one another. A positioning pin v10 (FIG. 1) is provided for each block 2 and 3, and acts as a dowel to ensure accuracy in the alignment of the cylinder bores 11.

Gperating in each of the cylinder bores 11 is a piston 12 extending outwardly of the bores. Each of the pistons 12 is provided with an outer surface or crown 13 which is a segment of a long-radius sphere,and which is adapted to cooperate with one of two inclined surfaces 14- and 15 provided on each of the eccentric reaction rings 16 and 17 (FIGS. 1, 2 and 3). These reaction rings have an axis 18 (FIGS. 2 and 3), which is offset from the axis 1 of the cylinder blocks 2 and 3. Each of the reaction rings provides equal and opposite sloping surfaces 14, 15 contacting all of the pistons 12. The resultant reaction between each ring and-its two series of pistons 12 is therefore radial to the axis 1.

A housing or casing member 20 of generally cylindrical configuration serves to enclose the blocks 2 and 3 and the other elements of the hydraulic structure. This casing 20 is provided with a cover 21 having a flange 22 telescoping within the casing 20. Bolts 23 fasten the cover 21 in place, and engage a flange 24 carried by the right-hand open end of casing 20. An O-ring 25 is disposed in a groove at the base of flange 24 for providing a substantially fluid-tight enclosure. No other gaskets or packing are necessary. Tightening of the bolts 23 serves to hold elements of the pump against relative axial movement, as will now be described.

The reaction rings 16 and 17, as shown most clearly rings 29 and 30. The left-hand side of ring 29 abuts a shoulder 31 formed within'the casing member 20. This shoulder is formed by the aid of a bore 32 having an axis coincident to axis 18 of the eccentric ring.

A sleeve 33 abuts the right-hand edge of ring 29 andserves as a spacer. The right-hand edge of this sleeve 33 is in engagement with the ring 30. This ring 36* is held against axial movement by the left-hand edge of flange 22.

In order to provide a bearing for the left-hand endof shaft 7, this shaft 7 has an enlarged end 34. This enlarged end forms a shoulder 35 against which cylinder block section 2a abuts. a

.The inner race 36 of a roller bearing structure 37 is disposed over this enlarged portion 34.' The bearing structure includes the outer race 38 and a series of rollers 39. The outer race 38 abuts the shoulder 40 formed within-the casing member 20. The inner race 36 has flanges 36a restricting axial movement of the rollers 39; and outer race 38 has a left-hand flange 38a for further confining the 'rollers. groove in enlargement 34 to confine the inner race 36.

At the right-hand end, the shaft 7 is provided with a bearing support of the same size and type as that described for :the left-hand end. A thrust ring 42 is mounted on the reduced shaft portion 7 b and its left-hand face engages block 3 and .urges it against shoulder 7a. This ring 42 is urged to the left by a nut 47 mounted on the threaded end of shaft 7 and held in place by a cotter pin 47a.

The ring 42 has a periphery corresponding in size to that of enlarged portion 34 at the left-hand end of shaft 7. It is provided with a flange 41 against which is posi tioned the inner race 43 of a roller bearing structure 44;

The outer race 45 cooperates with inner race 43 to confine the rollers 44a in the same manner as the inner and outer races 36 and 38confine the rollers 39. The outer race 45 is accommodated in an internal cylindrical surface 46 formed in cover 21 and engaging a shoulder 46a. A spring ring 43a is positioned in a groove in ring 42 for. confining the inner race 43 against axial movement.

Both the roller bearing structures 37 and 44 for the shaft 7 are substantially identical; they adequately sustain the radial and thrust loads, and by virtue of the positioning surfaces 40 and 46a, the axial spacing of the blocks 2 and 3 with relation to the other parts is definitely determined.

The existence of high hydraulic pressure in the cylinders 11 of the cylinder block 2 causes a hydraulic thrust to be developed in a left-hand direction against shoulder 35. Similarly, the high hydraulic pressure in the cylinders 11 of the block 3 causes a hydraulic thrust to be developed in a right-hand direction against the ring 42. The bearing structures 37 and 44 do not have to sustain these thrusts. The shaft 7 is placed under tension by the thrust forces against shoulder 35 and ring 42.

In order to form extended guides for the piston structures, the cylinder block sections are respectively provided with flanges 48, 49, 50, 51 constructed and arranged as set forth in said prior application. These flanges extend radially outwardly, substantially as far as the positions reached by the bases of the piston crowns 13 when the pistons 12 are at their extreme outer positions, so that the over-all outside diameter of each block section is substantially greater than the inside diameter of the reaction rings 16 and 17. These flanges are provided with arcuate extensions 52 of the cylinder bores. 'Each of these extensions include an angle greaterthan 180, and preferably about230". In this way, an effective safeguard is pro- A' spring ring 34a, operates in a" Y 4 vided against cocking of the pistons 12, which mayresult in distortion of the cylinder bores by the forces exerted between the eccentric rings16 and 17 and the pistons 12. The pairs of flanges 48, 49 and 50, 51 are opposed to each other and define a space in which the eccentric ring bearing structure may be accommodated. In this way there is a considerable reduction in radial dimensions.

. In order to-provide a drive connection with the cylinder 7 block structures 2 and 3, the shaft 7 is provided with a hollow extension 53 having internal splines cooperating with the splines of a drive shaft 54. A hollow cap 55 telescopes over the extension 53 and sealing O-ring 56 is interposed between the inner surface of the capand the 7 extension 53. This ring 56 is urged toward a retainer 57 by the aid of a compression spring 58 engaging within a groove formed in the left-hand face of the extension 53,

and acting on a follow-up ring 59.

In order to hold the cap against movement toward the left, the retainer 57 is disposed around the extension 53. It is held in place by a clamping ring 60 attached as by fillister screws 61 to the left-hand side of the casing member 20. An O-ring 62 seals between the recesses formed in retainer 57 and ring 60. A gasket or packing 63 may be interposed between the ring 60 and the casing 20. The adjacent surfaces of retainer 57 and cap 55 are in sliding engagement.

The running seal thus formed by ring 60, detainer 57, cap 55 and their related parts 59, 56, 58, 61 and 62 forms no part of this invention, but is a commercially available shaft seal.

The bores 11 of each pair of parallel cylinders in block 2, as well as in block 3, are in communication with each other through the ports 64 (FIGS. 1 and 3). These ports lead into transversely elongated inner portions 65 of the bores 11 (FIG. 6). Such elongated portions are described fully in said prior application. Thus, in FIG. 6 these elongated portions are generally crescent-shaped. There is a clear space for the inner ends of each of the pistons 12, permitting ready access of liquid between any two pairs of parallel cylinder bores. Crosscuts 12a may be provided in the lower ends of each of the pistons to. assist in the intercommunication between the cylinder bores.

'The valve arrangement for alternately connecting the cylinder bores to the inlet and outlet of the mechanism is efiected by the aid of a non-rotary valve plate 66 and rotary valve plates 67 and 68, respectively on opposite sides of the non-rotary plate 66. In this way, a non-rotary plate 66, common to both cylinder blocks'2 and 3, can be provided.

The rotary valve plates 67 and 6 8 are provided respectively with recesses 69 and 70. These recesses accommo date the compression springs 71 and 72 to urge these valve plates 67 and 68 toward the non-rotary valve plate 66. The outer ends of these springs abut the block sections 2b and 3b, respectively. Thus, seating of these plates during the starting of the apparatus or during other periods of zero discharge pressure is ensured. At other'times, the unbalanced hydraulic forces on these rotary valve plates 67, 68 urge them toward the fixed valve plate 66. Such forces operate through valve ports associated with the rotary plates 67, 68 and center valve plate 66.

Each of the rotary valve plates 67 and 68 is provided with a plurality of kidney ports 73 and 74 cooperating with ports 75, 76 in the non-rotary valve plate 66 (FIG. 2). These kidney ports 75 and 76, as shown most clearly in FIG. 2, are located within the non-rotary valve plate 66 and extend entirely through it. In this manner, these ports 75 and 76 simultaneously cooperate with the kidney ports 73 and 74in the rotary valve plates 67 and 68.

As shown most clearly in 'FIG. 2, the valve plate 66 is provided with diametrically opposite radial ports 77 and 78 cooperating with stationary sleeves 79 and 80 corresponding to inlet and outlet ports for the motor. These sleeves at their inner end are received in couuterbores for the ports 77 and 78 and also extend radially through the spacer sleeve 33. The outer ends of these sleeves 79 and 80 are accommodated within bores formed in the bosses 81 and 82 formed on the casing 20. In order to provide a fluid-tight structure O-rings 83 and 84 are provided in appropriate places around the sleeves 79 and 80.

To bottom these sleeves in the counterbores of the ports 77 and 73, use is made of the coupling nuts 85 and 86 arranged diametrically opposite With respect to each other and in threaded connection with the bosses 81 and S2. The end surfaces of these bosses are tapered as indicated for the accommodation O- rings 87 and 88. These coupling nuts also from appropriate connecting means into the hydraulic system Where the apparatus is used.

Thus, sleeves 79, 80 as positioned by nuts 85 and 86 hold the valve plate 66 non-rotary with respect to the casing 29 and also serve to position this valve against axial movement.

The kidney ports 73 and 74 located in the rotary valve plates 67 and 68 are arranged in a manner to be hereinafter described for cooperating with the cylinder bores 11.

Each of the elongated bore spaces 65, 66 (FIG. 1) communicates with a port 89 in the block section 2b or 3b. These ports 89 are provided in projecting bosses 96 inter-fitting into stepped bores of the rotary valve plates 67, 68. These valve plates are rotated by the aid of these projections as the blocks rotate. This type of rotary plate mechanism is the subject of an application filed April 16, 1956, in the name of R. H. Marvin and having Serial No. 578,313, now abandoned. Since both valve plates are identical, except that they are right and left hand, only one need be described.

The rotary valve plate 68, as shown most clearly in FIG. 4, is provided at its right-hand side with as many kidney ports 74 as there are cylinder ports 89. These kidney ports operate in succession with the inlet and outlet ports 75 and 76 of the non-rotary plate 66. The angular extent of each kidney port 74 is shown as slightly less than the angular spacing between the non-rotary kidney ports 75 and 76 (FIGS. 2 and 4). Thus, what is known as positive lap exists between ports 74 and ports 75, 76 so that ports 74 are never in communication simultaneously with both ports 75 and 76. The angular extent of each port 74, in relation to the angular spacing between ports 75 and 76, may vary with various applications, however. According to well-known valve design principles, lap or lead can be obtained by making ports 74 shorter or longer than that angular spacing, and in high speed hydraulic devices considerable lead is often necessary, and can be readily provided. Ports 74 are centrally provided with tapered inlet counterbores 91.

The bosses 90 have reduced extensions 92 telescoping into the bores 93 leading to the kidney ports 74; and in order to provide an appropriate seal for each of these projections, a plastic ring 94 extends around the extension 92 and abuts an anti-extrusion ring 95 which may be of metal or of plastic. The I'OOL 'POIIlOHS of bosses 90 interfit recesses 96, of corresponding diameters, in rotary valve plates 67 and 68.

If it be assumed that the apparatus is operating as a hydraulic motor, the sleeve 80 (FIG. 2) is connected to a source of hydraulic pressure to provide the motive fluid for the apparatus. The hydraulic liquid then flows through the port 78 into the kidney port 76; thence it flows into all those cylinder bores 11 which are located on the right-hand side of the plane P passing through the axes 1 and 18 (FIG. '3), having previously passed through the corresponding kidney ports 73, 74 (FIGS. 1 and 4). These axes respectively correspond to the axis of rotation of the shaft 7 and of the eccentric reaction rings 16 and 17.

The liquid then urges all those pistons 12 of both 6 blocks 2 and 3, which are located to the right of the plane P, outwardly against the corresponding reaction ring 16, 17, thus causing the blocks to rotate and to drive the shaft 7. Those cylinder bores 11 which are located to the left of the plane P discharge the liquid through their corresponding kidney ports 73, 74 into kidney port 75 of the non-rotary valve plate 66; thence through port 77 and sleeve 79 to the outlet side of the apparatus.

In FIG. '5, the forces and their reactions, tending to produce cocking of the cylinder blocks are indicated in a diagrammatic manner. FIG. 5 is a diagram, indicating the main elements of the apparatus in a simplified manner and corresponds mainly to a central section taken along a plane normal to plane P of FIG. 2.

The effects of these reaction forces are similar to those set forth in application Serial No. 354,018, filed May .11, 1953, in the name of Elias Orshansky, In, new Patent No. 2,809,594, issued October 15, 1957, which discloses hydraulic apparatus of the same general nature as that disclosed herein.

There are reaction forces R and R acting through bearings 26 and 37 at the left-hand end of the appara-- tus. Force R represents the force opposed to the resultant of the radial forces exerted by the pistons 12 against the reaction member 16. The direction of this resultant, as well as of the reaction force R is symmetrical with the kidney inlet port 75 (FIG. 2) since the radial forces acting on those pistons 12'subjected to inlet pressure and on one side of plane P (FIG. 3) are all greater than those pistons subjected to outlet pressure. The values of these reaction forces are equal, and the forces are spaced apart by a distance d creating a cocking torque corresponding to a clockwise torque C Another reaction force R acts upon valve plate 67 and I thereby upon the cylinder block 2. This reaction force represents the resultant of the fluid pressures acting between the stationary valve plate 66 and rotary valve plate 67. This resultant is in the same plane as forces R and R This produces a counterclockwise torque M since force R is at a radial distance from the axis 1; this radial distance is indicated by dimension r By appropriate choice of dimensions, the opposing torques C and M can be made substantially equal, thus neutralizing each other. I

The reaction forces R and R operating on cylinder block 3 are set up in the same Way as forces R and R They have a torque arm of d setting up a counterclockwise cocking torque C This torque C is substantially neutralized by the torque M set up by the reaction force R acting at a distance r from axis 1, and corresponding to force R and distance r The net forces operating on shaft 7 consist of the turning torque for transmitting the power created by the hydraulic motor, and simple tension corresponding to the forces tending to urge the surface 35 and ring 42 apart.

The inventor claims:

1. In hydraulic apparatus of the character described: a pair of cylinder blocks rotatable about a common axis and axially spaced from each other; a shaft means sup porting the blocks for rotation in unison about said axis; said blocks having cylinder bores with radial axes intersecting the said axis; pistons in said bores; means for reciprocating the pistons in the bores; each of said bores having a port extending toward the opposite blocks; and a non-rotary valve plate interposed between the blocks, and having a pair of ports equiangularly spaced about the axis, for cooperating with said ports of both blocks; the ports of said center valve plate being provided with openings adapted to be respectively an inlet and an outlet port, each port communicating with ports of both cylinder blocks.

2. In hydraulic apparatus of the character described: a pair of cylinder blocksrotatable about a common axis and axially spaced from each other; a shaft means supporting the blocks for rotation in unison about said axis;

said blocks having cylinder bores with axes intersecting the said axis; pistons in said bores; means for reciprocating the pistons in the'bores; each of said bores having tively an inlet and an outlet port, each port cornmuni-.

eating with ports of both cylinder blocks; and abutment means for the outer ends of the blocks and carried by the shaft means for sustaining the hydraulicthrust 'pro duced by the hydraulic pressures in the cylinder bores.

3. In hydraulic apparatus: a pair of axially spaced cylinder blocks having remote ends and rotatable about a common axis, each of said blocks having cylinder bores radial to said axis; means coupling said blocks so that they rotate in unison; pistons in said bores; eccentric reaction rings'respectively for the pistons in said blocks; said rings having eccentric surfaces in contact with the pistons; a non-rotary valve plate intermediate the blocks and having ports cooperating "with ports of the cylinder blocks; the ports of said center valve plate being pro vided with openings adapted to be respectively an inlet and an outlet port, each port communicating with ports of both cylinder blocks; said blocks having bearing structures located at the remote ends of the blocks; and hearing structures for the eccentric rings and intermediate the remote ends. a t

4. In hydraulic apparatus of the character described: a pair of cylinder blocks rotatable, about a common axis and axially spaced from each omega shaft means supporting the blocks for rotation in unison about said axis; said blocks having cylinder bores with axes intersecting the said axis; pistons in said bores; means for reciprocating the pistons in the bores; each of said bores having a port extending toward the opposite block; rotary valve 7 ,plates driven by the respective cylinder blocks and having ports aligned with the bore ports; a non-rotary valve plate interposed between the rotary valve plates and cooperating with said ports of the rotary. valve plates; said non-rotary valve platehaving a pair of through port passages forming respectively an inlet and an outlet port adapted to be connected in succession to the rotary valve plate ports; and abutment means for the outer ends of the blocks and carried by the shaft means for sustaining the hydraulic thrust produced by the hydraulic pressures in the cylinder bores.

5. In hydraulic apparatus of the character described:

a pair of cylinder blocks rotatable about a common axis and axially spaced from each other; a shaft means supporting the blocks for rotationin unison about said axis; said blocks having cylinder bores with axes intersecting the said axis; pistons in said bores; rotary reaction rings for reciprocating the pistons in the bores; the pistons being so arranged that the resultant reaction upon the pistons is radial to the axis; a non-rotary valve plate interposed, between the blocks, and cooperating with said ports of both blocks; said valve plate having a pair of through port passages forming respectively an inlet and an outlet port adapted to be connected in succession to the cylinder ports; and a pair of bearing means for rotatably supporting those ends of the shaft means located on those sides of the cylinder block remote from the stationaryvalve plate; the resultants of the bearing reaction forces and the radial reaction forces on the pistons being spaced to produce substantially no resultant cocking torque on the cylinder blocks.

6. In hydraulic apparatus: a pair of rotary cylinder blocks; a shaft mounted in said blocks; said blocks being spaced along the axis of the shaft for rotation in unison; pistons radially operating in said cylinder blocks; a reaction ring for each set of pistons; said rings being spaced along said axis; bearing supports for the rings; a pair of bearing supports for rotatably supporting the shaft and located near opposite ends of the shaft; and a nonrotary valve plate intermediate the two blocks; said blocks having valving provisions respectively cooperating with opposite sides of the plate; said valving provisions including ports forming inlet and outlet ports for both blocks; there being radial reaction forces at all of the said bearings, as Well as forces parallel to the axis due to hydraulic pressures between the opposite sides of the plate and the valving provisions; the spacing and sizes of all said forces resulting in substantial neutralization of torques imposed on the apparatus by these forces.

References Cited in the file of this patent UNITED STATES PATENTS 1,152,729 Hole-Shaw Sept. 7, 1915 2,186,409 Ferris Jan. 9, 1940 2,227,631 Carter J an. 7, 1941 2,237,018 Tweedale Apr. 1, 1941 2,257,792 Fletcher Oct. 7, 1941 2,458,985 Ferris et al. Ian. 11, 1949 2,646,754 Overbeke July 23, 1953 2,716,944 Ferris Sept. 6, 1955 2,743,582 Wiedmann May 1, 1956 2,910,008 Weisenbach Oct. 27, 1959

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