US2307719A - Hydraulic pump construction - Google Patents

Description

Jan. 5, 1943. J. B. HAwLEY, JR

HYDRAULIC PMP CONSTRUCTION Original Filed March 7, 1958 5 Sheets-Sheet l llll l ,lll

Jan. 5, 1943. J, B. HAWLEY, JR 2,307,719

' HYDRAULIC PUMP CONSTRUCTION Original Filed March '7, 1938 5 Sheets-Sheet 2 Jan. 5, 1943. J. B. HAWLEY, JR

HYDRAULIC PUMP CONSTRUCTION 5 Sheets-Sheet 3 Jan- 5,1943-4 .IQ B. HAWLEY, JR 2,307,719

HYDRAULIC PUMPV CONSTRUCTION Original Filed March '7, 1938 5 Sheets-Sheet 4 /a/W y I Jan. 5, 1943, J. B. HAWLEY, JR 2,307,719

l HYDRAULIC PUMP CONSTRUCTION Original Filed March '7, 1938 5 Sheets-Sheet 5 Patented Jan. 5, 1 943i l UNITED :i sTATEsPATeN A 2,307,7l9 Y' V s HYDRAULIC PUMP CONSTR'JCIIONV John B. Hawley, .Ir.,:,Minn'eapolis,aMinn.v Original application March 7, 1938-,- Seral No. 196,225. Divided and this application January 24, 1941, Serial No. 375,742 s comms. (ci. 10s-.162)

This invention relates to a uid pump, motor or hydraulic transmission device and'particularly to such a. device of the kind known as the swash plate type. Such a device' comprises a rotating cylinder barrel in whichfpistonsreciprocate, these pistons being movable by a rotating swash plate rotating about the axis of the cyl-- inder barrel but being given a wobble motion by a tilting plate which can be tilted at various angles to theaxis of .said cylinder barrel.

It is an object ofl this invention to provide such a device having a tilting plate together with simple, novel and efficient means for varying the inclination of said tilting plate.

It is another object of the invention to provide a novel form of indicator showing the inclination of the tilting plate and one which will be nor-l mally covered and sealed.

Fig. 'Tis a view similar to Fig.` 6 showing a v modification;

Fig. 8 isa viewA as seen from linel I2-V-I2 of Fig. 7 looking in the direction of the arrows; and

Fig. 9 is a view similar to Fig. 6` showing a modification. l y

Referring to the drawings a'device such as referred to above is shown comprising a casing section I5. `of box-like form rectangular in vertical cross section. A front end plate I6 is secured to one `end. of casing I5, the same fitting tightly there- 'Y against and having therewith a rabbeted joint comprising a ledge and shoulder indicated at Ilia.

VA rear end plate or valve plate Il is provided tting against the other end of casing 'I5 and l also having therewith a'rabbeted or offset joint It is still further an object of the invention to provide a novel construction of discharge and inlet pipe in combination with the pump parts. It is further an object of the invention to provide a novel construction of frame or casing for the pump and a. novel form of supDQrting means for said casing.

It is also an object of Ythe invention to provide a novel combination of swash plate and attached parts and a casing'construction whereby removal of one or more parts is greatly facilitated.

These and other objects and advantages of n 'the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout 'the' cover being broken away to show the indicator;v

Fig. 5 is a view in vertical section taken substantially on line 5-5 of Fig'G as indicated by the arrows;`

Fig. 6 is a partialvertical section taken substantially en line 6 6 Iof Fig. 3 as indicated by' the arrow;

as indicated at Ila. Angle members or brackets I8 have verticall flanges disposed against the outer sides of plates I6 and I'I and have horizontal angesIa constituting feet or supports for the casing, the same havingholes I8b therethrough which may receive securing bolts'. Long screws I9 extend through section I5 and the plates I6 and I 'I as well as brackets I8, the saine being disposed adjacent the corners of the casing 4ways `21a in cylinder barrel 2l. l

threaded portion 26a adjacent its inner end re,

and being threaded-at their' ends tol receive the securi`ng"'nuts 20. Bolts I9 therefore 'secure said ,parts together. ,Similar bolts 2I extend through members I5, I6 and I1 adjacent the upper cor- .ners of the casing and are also equipped with nuts 20. Bolts 2| also act to secure the sections of the casing together. A bearing bracket 22 has an inner short flange22a set into the outer end of plate I6 and is recessed to carry a ball bearing 23. Plate I'I is recessed at its inner side to receive a ball bearing casing 24 and said plate also has a thrust platel 25 set therein-to. A ldriving shaft 2B is journalled in the bearings 23 and 24, the same 'having its inner end engaging plate y25 and having a shoulder engaging the inner side of bearing 23. A cylinder barrel 2l surrounds shaft 26 adjacent its inner end and. is secured thereto bythe oppositely disposed keys 28, said keys being shown as having cylindrical shanks or projections-fitting in similarly shaped holesin shaft 26.

Shaft 26 has a ceiving -a collar 29 and a nut 30 engaging said collar. Collar 29 engages a shoulder onl said shaft adjacent said threaded portion. "Shaft 26 has a yoke 2Gb formed thereon at the inner side of barrel 21 and a coiled compression spring 3| surroundsshaft 26 bearing at one end against As illustrated, this section is made Said keys extend into keyyoke 26h land at its other end against a barrel 21, said spring being partly disposed in the recess in barrel 21. Spring 3l acts to press cylinder barrel 21 against the -fiat face of the valve plate I1. Barrel 21 has a flat face engaging said valve vplate and has formed therein a plurality of cyling bushings 33`in which arejournalledl the ends of a main shaft pin 34. The central part of shaft pin 34 extends through a trunnion block 35.disposed within yoke 26h and having trunnions 35a at opposite ends projecting at right langles to pin 34. Trunnions ,35a are received in bushings 36, said bushings or bearings 36 in turn received in trunnion bearing blocks 311 which are received in swash plate 32 and locked therein. Swash plate 32 is thus rotated by shaft 26. Cylinder barrel 24 has a piston 38 in each of its cylinders, said piston having a bore in the inner end of which is disposed a ring socket 39 having a semispherical recess therein adapted to receive the end of a ball as formed on one end of a connecting rod 49. A connecting rod end bushing engages the outer end of a socket 39 also vhaving a surface fitting part of the other half of the ball 39a and held in place by a flanged hollow nut 42 threaded into the bore of piston 38, the iiange thereof engaging the end of said piston. While pistons 38 might be variously made, in practice it has been found highly emcient to have them made of steel, the cylindrical bearing portions of the pistons being coated with a coating 38a of hard bronze welded thereon. Connecting rod 49 has a ball 49h at its other end and swash plate 32 is provided with a plurality of sockets equal in number to and aligned with the cylinders in barrel 21. Each of said sockets has disposed therein a ring socket 43 receiving the outer end of ball 49h. A bushing 44 engages the member 43 and also has a partly spherical surface engaging ball 4917. 'A nut 45 is threaded into swash plate 32 and engages` member 44, the same being hollo'w to accommodate connecting rod 49. Some locking means not shown will be provided for locking nuts 42 and 45 in place. Swash plate 32 is recessed at its outer side to receive a h'ard bearing plate 46. A tilting plate 41 of ball-like form surrounds shaft 26 and has a large central opening through which said shaft passes. Plate 41 has rather large trunnions at either side thereof which are Journalled in roller bearings 48. The bearings 48 are carried in bearing brackets 49 which are secured to end plates I6 by the headed bolts 59 which pass through said brackets at the sides of bearings 49. It will be seen that are engaged by bearing sleeves 56 mounted on roller bearings 51 into which bearings the bearing shafts 58. Shafts 56 are secured in the sides of a yoke 59a formed on the lower end of a vertically extending control shaft 59. 'I'he yoke 59a has secured thereto a key member 69 fitting in a keyway in the end plate I6 and extending from the borel I6b formed in said end plate and in which the yoke or cage 59a slides, the latter having outer cylindrical surfaces as shown in Fig. 3. Key 69 is secured to portion 59a adjacent its top and bottom by the pins 6I. portion 59a are thus guided for vertical nonrotative movement. Shaft 59 passes through the flanged bushing 62 fitted into a cover member 63 closing the outer end of bore I6b and being bored to accommodate the packing material 64 pressed therein and about shaft 59 by the gland 65.' A stop block 66 has a reduced threaded stem secured Yin plate I6 at the bottom of bore I6b and limits the downward movement of shaft 59. It will be seen that by raising land lowering shaft 59 that block 53 will be raised and lowered and this in turn will move plate 41 about the axis of its trunnions. Block 53 can move parallel to the axis of shaft 26 but can have no rotative movement. Plate 41 is recessed to receive a bearing plate 61 and roller bearings 68 are disposed between plate 61 and plate 46. lPlate 46 at its outer edge also engages roller bearings 69 so that swash plate 32 rotates against both bearings 68 and 69.

Casing section I5 is provided with a cylindrical opening I5a and a reduced cylindrical portion of a bracket 19 fits into said opening,'bracket 19 being secured to the side of -section I5 by a plurality of circumferentially spaced screws 1I having-their heads countersunk into member 19.

' The adjacent 'trunnion lof tilting plate 41 is recessed to receive the flange 12a of a member 12, said il'ange being secured to said trunnion by the circumferentially spaced bolts 13. Member 12 has a cylindrical portion projecting outwardly from flange 12a and this extends through a cylindrical central opening in bracket 19, the same projecting a short distance beyond the outer surface of bracket 19. An indicator pointer 14 is provided'with a hub set into the outerjend of member 12 and said hub and pointer are secured tilting plate 41 may-be tilted about the axis of e' its trunnions which axis extends perpendicularly`to the axis of shaft 26. Tilting plate 48 also carries and 'forms a support for the swash plate 32. For the purpose of tilting plate 41 a fork 5I is provided having a cylindrical shank 5Ia fitted into a boss on plate 41 and secured therein by a tapered pin 52. Fork 5I has flat surfaces at'the inner sides of its arms between which is disposed'a block 53. Block 53 is centrally bored to receive the roller bearings 53 and a pin 55 extends centrally through bearings 54 and has its ends disposed in the arms of fork 5I. Block 53 has flat top and bottom sides and these to member 12 by the headed bolt 15 engaging a washer 16. A pin 11 also extends through pointer 14 into member 12. Pointer 14 cooperates with graduations14a formed on the face of member 19. Packing 18 surrounds member 12 within member 19 an`d is carried in a casing 19. The pointer 14 is covered and enclosed by cover plate 89 secured to member 19 by the circumferentially spaced headed screws 8 I, a gasket 82 being placed between said members to insure a tight seal.

As stated, end plate I1 forms a valve plate and is provided with a bronze surface I1b welded onto said plate which is' made of Invar steel. This steel used contains about 57 percent nickel and has one-twenty-fifth the coefficient of expansion .of regular steel. Outside of bearing 24 the face of the valve plate is tightly engaged by the outer flate face of barrel 21. Valve plate I1 has an annular bearing surface I1c and this is provided with diametrically opposite arcuate slots I1d, one of which forms an inlet port and the other of which forms an outlet port. These slots extend through plate I1 and communicate with the dis charge openings Ile. Small grooves Ildd extend from each end of slots I1d for a short distance. The outer side of plate I1 is provided with a pair Shaft 59 and the of parallel bores in alignment with the discharge openings I1e and rings 85 are disposed in the bottom of said bores against the'sho-ulder formed therein, said rings having inwardly extending anges 85a. Coupling members 86 have cylindrical pipe portions Iextending into reduced extensionsA of the boresin plate I1, said portions each having an annular groove 86a formed therein in which the flanges 85a ofthe rings 85 extend. Rings 85must of course, bein two parts. Packing 81 is disposed in said bores engaging the rings 85 at'its inner ends and being engaged at its outer end by the glands 88, saidpacking thus being tightly pressed about the pipe portions of members 86. Glands 88 as usual have anges -through which extend the headed bolts 89 threaded into the end of plate I1. The inlet and discharge conduits`99 are suitably connected to members 85. As shown in Fig. 1 packing material 9| is disposed in member 22 about shaft 26, said material being engaged by the cylindrical portion of a packing gland 92 extending into the bore of member 22. Gland 92 has a flange through which pass the bolts 02a threaded into Y. member 22 and material 9| is thus compressed about shaft 26. shown as having a reduced portion threaded with a keyway 26o adapted to receive a suitable.. driv- The outer end of shaft 28 is ing member. Casing I5b is shown as having an opening I5d in its top about which is secured a member 93 having an annular flange 93a entering an annular groove I5ein casing I5. A gasket may be placed beneath flange 93. Member 93 Said plunger is kept from rotation by having a keyway in its outer side in which is disposed the key 99 secured to plate I1; Plunger 98a is out away at its inner side to have a flat surface substantially in the plane of its axis and the other ends of bands 95 and 96 are secured respectively to the upper and lower portions of this surface by the bolt |00 and pins I 0|. The lower end of bore Ib is closed by a anged plug |02 and the upper end of said bore is closed by a anged plug |03. Plug |03 is bored to have a flanged bushing |04 at its innerv portion surrounding shaft 98 and packing |05 surrounds said shaft in the bore of member |03 and engages bushing |04. A gland |06 surrounds shaft 98 and extends into the bore in member |03 13o-engage and compress the packing |05 about shaft 98.- Shaft 98 shown as -interiorly threaded and is provided is shown as having a reduced threaded portion A 98h at its upper end which will receive some suitable means for moving said shaft. It will be seen Y that when shaft 98 is moved vertically that plate 94 will be rotated about itsztrunnions in a counter-clockwise direction. The bands 95 and 96 move over the convex or semi-cylindrical outer portion of projection 94a. When shaft 98 is moved downwardly plate 94 will be tilted in a clockwise direction about its trunnions.

In Fig. 9 a further modication is shown in which the tilting plate IIO similar to plate 41 form of a fork between the arms of which is secured a member III having spaced annular ribs or projections |||a thereon. A plug I|2 closes the lower end of bore Ib and at its inner end is provided with a thrust Timken bearing vI |3. A ange plug I|4 closes the upper end of bore'IGb and also carries at its inner end a thrust Timken bearing II5. An adjusting shaft IIS extends through bearings I I3 and I I5 and is provided with` shoulders engaging the adjacent sides of said bearings. Shaft I|6 is provided adjacent member ||I with a worm or helical gear formation II6a. Member II4 is bored to receive a flange' bushing II1 surrounding shaft I|6. Packing material H8 is disposed in the upper and enlarged gear or worm portion |I6a and member or plate I|0 will berotated vin a clockwise or counterclockwise direction depending upon the direction of rotation of shaft II6. The parts are held firmly and securely in position and no play is permitted in said parts due to the arrangement of the bearings II3 and II5.

In operation, shaft 26 will be driven and if the deviceV is being used .as a'pump the conduit 90 which is opposite the port |1d aligned with openings 21c when the pistons 38 move awayfromi plate I1 will be connected to the inlet supply of oil or fluid to be pumped. The other conduit will'then form the discharge conduit. Plate 41 will be tilted to the desired angleby upward move-v ment o'f shaft 59. Such upward movement as already stated, inoves block 53 and this swings plate 41. The stroke of the pistons 38 is determined by thedegree of inclination of plate 41.

With plate 41 so inclined swash plate 32 is rotated b y shaft 26 through the trunnion block 35 and when the roller bearings 68 approach the side oi plate 41 nearest the cylinder barrel, said bearings and plate will be moved toward the barrel and through the. connecting rods 40 pistons 38 will likewise be moved.- As the bearings 68.ap

proach the side of plate 41 farthest from the barrel 21 the pistons will be moved outwardly of the cylinders and barrel 21. The liquid entering the inlet pipe 90 willl pass through members 86, inlet members 'I1e, the inlet port I1d and through the opening 21C into the cylinders in barrel 21. Liquid is thus drawn into the cylinders as the pistons move away from barrel 21. As the barrel v21 and swash plate 32 rotate the cylinder with the liquid therein will move into registry with the discharge port I1d and the pistons are then vmoved into the cylinder and the liquid is -discharged through the openings 21e and discharge -openings I1einto the other member 86 andthe discharge conduit 90. It will be seen that some 4motion of the inlet and discharge. conduits 90 'of the cylinder barrel. The elimination of the stresses placed on the valve plate bythe inlet and discharge pipes is thus a great improvement.

There is a considerable Adifference in tempera-- ture of the incoming and outgoing oil due to the Packing material II8 is thus comhigh pressures developed in the pump and it is necessary to have a valve plate which has a very low coemcient of expansion. This problem has been solved in the present case by using a high nickel Invar steel as above described. The pistons 38 being coated with a coating of hard bronze welded onto the steel are also very strong and durable and there is low friction between the pistons and the cylinder wall. The construction of 4' applicants casing also results in a great improvement. Not only are the parts comparatively simple and easily made but it will be seen that when the plate I1 is removed that the bolts l. holding the tilting plate trunnion bearings can then be removed. The indicator member 12 can 15 be removed and the whole pump mechanism including the shaft 26, swash plate 32 and the cylinder barrel ycan be removed through one end of casing section i5. It will be seen that block 53 can be removed from between the bearing sleeves 56. 'I'he casing section i5 is of exceedingly simple construction. A simple and eicient connecting means for the casing is also provided by the long bolts i9 which also hold the feet brackets I8. -By providing roller bearings for the trunnions of tilting plate I1 this plate may be quite easily adjusted. /There is a considerably impending motion or gyroscoplc effect on this part and this is practically eliminated by the provision of the roller bearings. The mechanism provided for adjusting the tilting plate is very simple and highly efficient. No play can take place between the parts 53, 59a and the fork Il,

The structure of the indicator comprising the pointer 14 is also novel. It is not desired to observe this with great frequency. It is'sometimes desired to know when the pump is in neutral -position that is when there is no inclination of plate I1. At such times the cover lli may be removed and the setting of the plate observed. Member 10 and packing means 18 and 19 are provided to prevent leakage of appreciable duid while cover plate 8l is removed. At other times the indicator is entirely closed and sealed and is thus not subject to any injury.

The cylinder casing i2ii indicated only in Fig. 2, may be used disposed about the rotating parts between plates i8 and I1 -and within the bolts Il and 2| to prevent friction of the iiuid in the casing with. said bolts. Said casing will be made of light metal of comparatively small thickness.

From the above description it will be seen that I have provided a simple, novel and greatly improved structure of a pump or iiuid transmission device of the swash plate type. The device is a great 'improvement over the devices of the prior art. 'I'he same has been amply demonstrated in actual practice, has been found to be ver! suc cessful and efficient and is being commercially made.

It will be understood, ofcourse, that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consistsin a device o5 capable \of carrying out the obiects above set forth, in the' parts and combinations of parts disclosed and ldefined in the appended claims.

This application is a division of applicant's c0- pending application Serial No. 196,225, filed 70 March 1. 1938.

v1. A pump or hydraulic transmission deviceE of the swash plate time having in combination, a'casingof rectangular box-like form. end plates 75 end. plate for .moving said member vertically and engaging opposite ends of said casing for closing the same and having a rabbeted joint with said casing, bearings carried bysaid end plates, a shaft journalled in said bearings, a cylinder barrel having a plurality of cylinders therein4 secured to said shaft and rotating therewith, one of said end plates forming a valve plate against which said barrel engages.'a swash plate surrounding said shaft and driven thereby. pistons in said cylinders operatively yconnected to said swash plate, 'bolts `extending between .and through said end plates for-securing the same to said casing, said shaft, cylinder barrel, swash plate, pistons and connections being removable by removal of said other plate.

2. The structure set forth in claim l, a tilting plate engaged by said swash plate and having y trunnions at either side thereof, bearings in which said trunnions are mounted and bolts extending through said bearingsinto said other securing said bearings to said i end plate.

3. The structure set forth in claim 1 and a casing extending about said rotating parts within said bolts for. preventing friction of fluid on said bolts.

4. A device of the class described having in combination, a casing, a rotary cylinder barrel,

pistons mounted for reciprocation therein, a shaft secured to said barrel for rotating the same, a swash plate mounted for rotation about said shaft, connections between said swash plate and said pistons, a tilting plate having trunnions journaled in said casing, said casing having an opening at one side axially aligned with one of said trunnions, a member having a flange removably secured to said casing and having a portion ntting in and secured to said casing extending intosaid opening, a second member secured to said trunnion and extending through and iournalled in said member, a pointer secured to said second member without said casing forming an indicator, a cover-for covering and tightly sealing said pointer and means for preventing leakage of an appreciable amount of iluid when said cover is removed.

.5. A pump of hydraulic transmission device of the swash plate type having in combination, a rotating shaft, a swash plate rotated by said shaft, a tilting plate engaged by said swash plate and tiltable about an axis perpendicular to the axis of said shaft, a member having a stem secured to said tilting plate and a fork portion projecting therefrom, the arms of which have-adjacent fiat sides, a block disposed betweentiie sides of said fork and movable longitudinally therein, a pin extending through said fork and through said block between the sides carried in said fork, anti-friction bearings engaging the top and bottom of said block. a member in which said bearings are secured, said block being movable between said bearings relatively to said member, said member also embracing the sides of said fork, means for means causing said member to movevertically and nonrotatably.

8. A pump or of the swash plate a honow` bo -like frame in vertical cross section, cured to one end of said frame, a rear end plate secured to theother end of said frame, bearings carriedby said endplates, aL shaft iournalled in said bearings, a cylinder b secured to and hydraulic transmission device type having in combination, of rectangular form a front end plate serotating with said shaft, a swash plate rotated by said shaft, pistons in said cylinder barrel operatively connected to said swash plate and bolts having threaded ends extending through said end plates and casing adjacent the corners thereof, nuts on the ends of said bolts for se curing said end plates and casingtogether, a tilting plate in which said swash plate rotates having trunnions at the sides thereof respectively, bearings for said trunnions within said casing and bolts extending through said bearings and securing the same to said front end plate whereby when said last mentioned bolts are removed and said rear end plate removed, said shaft, barrel, swash plate, bearings and tilting plate may be removed through one end of said frame.

7. In a pump of the class described having a casing and a tilting plate in said casing adapted to carry a swash plate, said tilting plate being swingable about a transverse axis, the combination of a member projecting above said casing and having a portion disposed* in said casing,

said portion having an opening therethrough substantially rectangularin vertical cross s ection, a. fork member having a stem secured in said plate and having its fork portion disposed in said openingl with its side portions adjacent casing, a swash plate mounted for rotation about an axis inclined to the axis of saidbarrel, means for varying the inclination of said swash plate including` an adjustable support in which said `swash plate is rotatably mounted, a fork having a stem rigidly secured to'saidsupport and having its fork portion projecting at one side thereof, said fork having laterally spaced arms, a4 block fitting between said arms of said fork, a pin extending through said block and said arms and journalled in said block thus permitting rela` tive swinging movement of said fork and said block, said member being constructed and arranged to be moved vertically to move vsaid block and tilt said fork and support, said block having movement relative Ato said last mentioned member.

9. In a pump or hydraulic transmission de.- vice of the swash platetype, a frame, fa shaft joumalled in said frame, a tilting plate adapted to be engaged by a swash plate. and having trunnionsl at its sides respectively journalled in said frame about a transversely .extending axis, a member movable vertically' in said frame at one side of said shaft and extending to the outer side of said frame, said member carrying vertically spaced roller bearings, a block between said bearings having at top and bottom surfaces engaged respectively by saidbearings, said bearings engaging said block at spaced points longitudinally of said shaft, a fork having laterally spaced arms between which said block i'lts, a pin connecting said. block and fork for relative swinging movement, said fork having ai stem rigidly secured to said tilting plate, `said member having portions extending vertically at the sides of said fork and guided for vertical movement in said frame, said member being constructed and arranged to be moved vertically at the outer side of said frame for moving -said block vertically, tilting said fork and thus tilting said tilting `plate to vary the angle thereof.

JOHN B. HAWLEY, JR.

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