US3838952A - Gear pump and motor having a sealed lock for preventing hydraulic oil from leaking between the ends of the teeth of the gears - Google Patents

Gear pump and motor having a sealed lock for preventing hydraulic oil from leaking between the ends of the teeth of the gears Download PDF

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Publication number
US3838952A
US3838952A US00317707A US31770772A US3838952A US 3838952 A US3838952 A US 3838952A US 00317707 A US00317707 A US 00317707A US 31770772 A US31770772 A US 31770772A US 3838952 A US3838952 A US 3838952A
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United States
Prior art keywords
seal block
gears
motor
pressure chambers
gear pump
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US00317707A
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K Hirose
Y Kitta
K Morita
M Futamata
T Nukada
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Komatsu Ltd
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Komatsu Ltd
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Publication date
Priority claimed from JP827272U external-priority patent/JPS4884014U/ja
Priority claimed from JP955572U external-priority patent/JPS4887606U/ja
Priority claimed from JP955372U external-priority patent/JPS4887605U/ja
Priority claimed from JP955272U external-priority patent/JPS4887604U/ja
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
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Publication of US3838952A publication Critical patent/US3838952A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C19/00—Sealing arrangements in rotary-piston machines or engines
    • F01C19/02—Radially-movable sealings for working fluids
    • F01C19/025—Radial sealing elements specially adapted for intermeshing engagement type machines or engines, e.g. gear machines or engines

Definitions

  • a drive gear and a driven gear are engaged in mesh with each other in a housing, and for example.
  • this gear pump and motor when this gear pump and motor is used as a pump, fluid is intaken from an inlet by means of the rotation of the drive and driven gears. and is fed out from an outlet as high pressure (when the gear pump and motor is used as a motor, fluid intaking side becomes high pressure).
  • a seal block is so disposed that the teeth ends of the drive and driven gears are contacted with each other in the housing at high pressure side.
  • the pressure distribution of hydraulic fluid for acting onto the contacting portion of the seal block at the drive side and the pressure distribution of hydraulic fluid for acting onto the contacting portion of the seal block at the driven side are different with the result that one hydraulic pressure becomes higher than the other hydraulic pressure so that there takes place a couple of forces that overall the seal block rotates along the outer periphery of the seal block. Therefore, the contacting of the teeth ends of the gear with the contacting portion of low pressure side becomes stronger than the other with the result that one side is worn as its disadvantage.
  • the width of the seal block is made equal to the width of the gears in the conventional gear pump and motor so that the longitudinal movement of the seal block is affected only by the hydraulic force. if the urging force of the seal block onto the gears is strong, the seal block is gradually worn by means of the contacting with the teeth ends of the gears.
  • This invention contemplates to eliminate the aforementioned disadvantages of the conventional gear pump and motor, and to provide an improved gear pump and motor.
  • One characteristic feature of the present invention is a gear pump and motor having a housing. a pair of gears engaged with each other, and a seal block disposed between the inner surface of the housing at high pressure side and the teeth ends of the gears, which comprises the seal block having a passage formed therethrough for hydraulic oil a plurality of pressure chambers formed between the inner surface of the housing and the seal block. and a plurality of holes formed in the seal block for communicating the pressure chamber with the gear side.
  • FIG. 1 is a longitudinal sectional view of the conventional gear pump and motor
  • FIG. 2 is a schematic view of the conventional gear pump and motor for explanatory purpose
  • FIG. 3 is a longitudinal sectional view of the gear pump and motor of the present invention.
  • FIG. 4 is a sectional view of the gear pump and motor taken along the line IV IV in FIG. 3;
  • FIG. 5 is an enlarged perspective view of one embodiment of the seal block used in the present invention.
  • FIG. 6 is a side view of the seal block showing the state of the pressure distribution acting onto the seal block
  • FIG. 7 is a side view of another embodiment of the seal block used in the present invention.
  • FIG. 8 is a side view of a further embodiment of the seal block used in the present invention.
  • FIG. 9 is a back view of the seal block shown in FIG. 8;
  • FIG. 10 is a sectional view of another embodiment of the gear pump and motor of the present invention.
  • FIG. 11 is an enlarged partial view at the part XI in FIG. 10;
  • FIG. 12 is an enlarged partial view at the part XII in FIG. 10;
  • FIG. 13 is a longitudinal sectional view of the essential part of a further embodiment of the present invention.
  • FIG. 14 is a plan view of the plate used in this invention.
  • FIG. I5 is a sectional viewof the plate taken along the line XV XV in FIG. 14;
  • FIG. 16 is a longitudinal sectional view of still another embodiment of the present invention.
  • FIG. 17 is a front view of the essential part of the present invention.
  • FIG. 18 is a sectional view taken along the line XVIII XVIII in FIG. I7;
  • FIG. 19 is a perspective view of the seal plate used in the present invention.
  • FIG. 20 is a plan view of still another embodiment of the seal plate used in the present invention.
  • FIG. 21 is a sectional view of the seal plate taken along the line XXI XXI in FIG. 20;
  • FIG. 22 is a sectional view of the seal plate taken along the line XXII XXII in FIG. 20;
  • FIG. 23 is a schematic view of the seal plate used in the present invention for the explanatory purpose.
  • FIG. 24 is a side view partially omitted of still another embodiment of the present invention.
  • FIG. 25 is a schematic view of the essential part of the device shown in FIG. 24-;
  • FIG. 26 is a sectional view taken along the line XXVI XXVI in FIG. 25;
  • FIG. 27 is a view seen in the direction by an arrow XXVII in FIG. 26.
  • a drive gear 2 and a driven gear 3 are engaged in mesh with each other in a housing I, and for example, in the event that this gear pump and motor is used as a pump, fluid is intaken from an inlet 4 by means of the rotation of the drive and driven gears 2 and 3, and is fed out from an outlet 5 as high pressure (when the gear pump and motor is used as a motor, fluid intaking side becomes high pressure).
  • a seal block 6 is so disposed that the teeth ends of the drive and driven gears 2 and 3 are contacted with each other in the housing I at high pressure side.
  • the conventional seal block 6 of the gear pump and motor is symmetrical with respect to the engaging center of the drive and driven gears 2 and 3 as shown in FIG. 1, the pressure distribution of hydraulic fluid for acting onto the surfaces 6a and 6b of the seal block 6 contacting the drive and driven gears 2 and 3 is different at the drive side and at the driven side in every half pitch of the gears 2 and 3, as shown in FIG. 6. Therefore, the seal block 6 vibrates, or one contacting portion 6a or 6b of the seal block with the gear is worn so that the seal block 6 is displaced to one side. Thus, it is impossible to obtain stable sealing of the teeth ends of the gears 2 and 3 of the gear pump and motor.
  • the pressure distrubution of hydraulic fluid for acting onto the contacting portion of the seal block 6 at the drive side and the pressure distrubution of hydraulic fluid for acting onto the contacting portion of the seal block 6 at the driven side are different with the result that one hydraulic pressure becomes higher than the other hydraulic pressure so that there takes place a couple of forces that overall the seal block 6 rotates along the outer periphery of the seal block 6. Therefore. the contacting of the teeth ends of the gear with the contacting portion of low pressure side becomes stronger than the other with the result that one side is worn.
  • the width of the seal block 6 is made equal to the width of the gears 2 and 3 in the conventional gear pump and motor as shown in FIG. 2 so that the longitudinal movement of the seal block 6 is affected only by the hydraulic force. if the urging force of the seal block 6 onto the gears is strong. the seal block 6 is gradually worn by means of the contacting with the teeth ends of the gears 2 and 3.
  • FIGS. 3 to 5. show one embodiment of the gear pump and motor of the present invention.
  • a seal block 6 is disposed between the inner surface 8 of a housing 1 at high pressure side and the teeth ends 10 and 12 of gears 2 and 3 engaged with each other. and has a chamber 14 formed therethrough for hydraulic oil. and pressure chambers I6 are formed between the inner surface 8 of the housing 1 and the seal block 6. Holes or passages 18 are formed in the seal block 6 for communicating the pressure chamber 16 with the gear side.
  • the seal block 6 is so formed as to be the same width that of the gears 2 and 3. and the housing is composed of a body 1a and a cover Ib connected by bolts 20.
  • Numeral 22 represents an inlet, and 24 represents an outlet.
  • Seal rubbers 34 and backup plates 36 are provided in the pressure chamber 16 for preventing high pressure hydraulic oil from leaking from the contacting surfaces of the inner surface 8 of the housing 1 and the seal block 6.
  • the drive gear 2 is journalled with a drive shaft 26, and the driven gear 3 is journalled with a driven shaft 28.
  • the shafts 26 and 28 are rotatably mounted to the housing I through bearings 30.
  • Numeral 32 represents circular side plates which are disposed between the gears 2, 3 both ends of the seal block 6 and the inner surface of the housing 1, respectively.
  • a hole 38 is formed in the side plate 32 to communicate with the chamber 14.
  • the side plate 32 is always urged in contact with the gears 2 and 3 and the both ends of the seal block 6 by high pressure hydraulic oil introduced between the inner surface of the housing I and the side plate 32, that is, by the hydraulic pressure in the chamber 14, so as to prevent the hydraulic oil from leaking from the gears 2 and 3 and both ends of the seal block 6.
  • movable type side plate push type
  • stationary type side plate may also be used within the scope of this invention.
  • the seal block 6 since the pressure chamber 16 is formed at the seal block 6 to be communicated with the gear side through the holes 18 as this is used as a pump, the seal block 6 is always urged in the direction to contact with the teeth ends 10 and 12 of the gears 2 and 3 by the discharge pressure of the hydraulic oil at high pressure side, and even if the discharge pressure becomes high so that the gears 2 and 3 are moved to low pressure side or intake side in case of pump, since the seal block 6 moves followed by the movement of the gears 2 and 3, the contacting of the teeth ends 10 and 12 of the gears 2 and 3 with the seal block 6 may be always kept constant, and accordingly it is possible to prevent high pressure fluid from leaking from the teeth ends 10 of the gears 2 and 3. Further, since it has less part acting with the high pressure. it is possible to reduce the hearing load at the same time to reduce the thickness of the housing.
  • FIGS. 6 and 7 another embodiment of the seal block used in the gear pump and motor of the present invention will now be described.
  • the seal block 6 is so formed as to be asymmetrical with respect to the engaging center of the gears 2 and 3 in such a manner that the contacting portions 6c and 6d of the seal block 6 with the gears 2 and 3, respectively are displaced by half pitch of the gears in circumferential direction of one gear.
  • the length of arcuate of the contacting portions 6c and 6d are equal, and its length is slightly longer than the length of one pitch of the gear plus the width of the teeth ends.
  • the contacting state of the contacting portion 60 of the seal block 6 and the drive gear 2 becomes the same as the contacting state of the contacting portion 6d of the seal block 6 and the driven gear 3 so that the pressure distrubution acting onto the contacting portions 60 and 6d becomes equal, as shown in FIG. 7.
  • This pressure distrubution is varied as the teeth ends moves, but becomes equal at both contacting portions 60 and 6d.
  • FIGS. 8 and 9 show a further embodiment of the seal block used in the gear pump and motor of the present invention.
  • holes 42a and 42b are formed from the contacting portions 6a and 6b of the seal block 6 toward the center of the seal block 6 in such a manner that both holes 42a and 42b are crossed at their ends so as to communicate the contacting portions 6a and 6b with the holes 42a and 42b.
  • the opened position of the holes 1 42a and 421; are symmetrically disposed at the contacting portions 6a and 6b of the seal block 6, and are disposed substantially intermediate in arcuate direction of the contacting portions.
  • the lateral position of the holes 420 and 42b are any place at right and left position of the passage 14 of the seal block 6.
  • the contacting portion 6a contacting with the drive gear 2 and the contacting portion 6b contacting with the driven gear 3 are communicated with each other through the holes or passages 42a and 42b so that the pressure acting onto the contacting portions 6a and 6b of the seal block 6 becomes equal.
  • the holes 42a and 42b are formed in the seal block 6 in the above embodiment, they may be formed on the side surface of the seal block 6 as grooves so as to communicate with the contacting portions 6a and 612, or grooves may be provided on the side plate 32. In this case, it is necessary that both side surfaces must be cut to form grooves so that the thrust force may not act onto the seal block 6.
  • FIGS. 10 and 12 which show still another embodiment of the gear pump and motor of the present invention
  • the center pressure chamber 16b is communicated between the gears 2 and 3 through the passage I4, and a stepped portion 44 is formed at the opening of the pressure chamber 1612 at the passage 14, and a collar 46 is engaged at the outlet 22 of the housing 1 to be inserted into the stepped portion 44 so as to from a throttle 48 with the collar 46 and the stepped portion 44.
  • the pressure chambers 16a and 160 are communicated between the gears 2 and 3 through holes 18a and 181;, respectively, and throttles 50 and 52 are formed at the holes 180 and 18h, respectively.
  • O-rings 54 are engaged with the pressure chambers 16a, 16b and 16c to be urged onto the inner peripheral surfaces of the housing 1.
  • the seal block 6 is composed of a seal block body 6c and a plate 6f. More particularly, the seal block body 6c has holes 18a, 14 and 18b therethrough, and the plate 6f also has holes 56, 58 and 60 and is bent along the outer surface of the seal block body 6c. This plate 6f is so disposed in the housing 1 as to be superimposed on the outer surface of the seal block body 6e in such a manner that the holes 56, 58 and 60 form pressure chambers 116a, 16b and together with the outer surface of the seal block body 60. O-ring 54 are disposed in the pressure chambers 16a, 16b and 16c.
  • FIG. 16 shows still another embodiment of the gear pump and motor of this invention, and the pressure chambers 16a, 16b and 160 are formed on the inner surface of the plate 6ftogether with the outer contacting surface of the seal block 6, and a hole 62 is formed in the pressure chatnher 16/) at the center thereof. and the outer surface of the plate 6/ is slidingly contacted with the inner peripheral surface of the housing I.
  • the seal block 6 is composed of the seal block body 6e having the holes 18a, l4 and 180, and the plate 6f having the pressure chambers 16a, 16b and 16c opposite to the holes 18a, 14 and 18b in contact with the outer surface of the seal block body 62, and accordingly the plate 6]" is simply constructed in such a manner that only holes are formed at the plate and the plate 6f is bent along the outer surface of the seal block body 6e, the pressure chambers are very easily formed so as to improve the accuracy thereof.
  • FIGS. 17 to 23 show still another embodiment of the gear pump and motor of the present invention.
  • the pressure chambers 16a, 16b and 160 are formed on the outer surface of the seal block 6, and are communicated between the gears 2 and 3 through the holes 18a, 14 and 18b. As shown in FIG. 17, these pressure chambers 16a, 16b and 160 have the same length of the width as the width of the seal block 6, and seal plates 64 of the same length as the total length of the pressure chambers 16a and 160 are engaged slidably in the pressure chambers 16a and 16c. As shown in FIGS. 20 to 22, the seal plate 64 may have a recess 66 at the inside surface, or as shown in FIG. 19, it may be of planar shape. A seal plate 70 formed with a hole 68 therethrough is slidably engaged at the center in the pressure chamber 16b.
  • hydraulic oil between the gears 2 and 3 acts to the pressure chambers 16a, 16b and 160 through the holes 18a, 14 and 18b with the result that the seal plates 64 and 70 are urged onto the inner peripheral surfaces of the housing 1.
  • the seal block 6 is moved laterally of the drawing, and there are produced gaps between the seal block 6 and the inner peripheral surface of the housing 1, and accordingly high pressure hydraulic oil tends to flow to the end surfaces 6g of the seal block 6 from the gap of the pressure chambers 16a, 16b and 160, but since the end surfaces 6g are urged by the side plates 32, the hydraulic oil cannot flow out therefrom.
  • the present invention comprises the seal block 6 formed with the pressure chambers 16a, 16b and 160 having the same length as the width of the seal block on the outer surface thereof, seal plates 64 having the same length as the length of the pressure chambers 16a, and 160 and slidably engaged with the pressure chambers l6a, and 16c, seal plate 70 having the same length as the length of the pressure chamber 16/), and a hole 68 at the center thereof and slidably engaged with the pressure chamber 16b, and side plates 32 contact at both ends of the seal plates 64 and 70, the pressure chamber may be formed along all the width of the seal block in comparison with the pressure chamber containing the O-rings and backup rings as the foregoing embodiment so that the working is easy so as to provide easily accuracy, and since the seal plate is used instead of O-ring, its breakage is less so as to improve its endurability.
  • collar 6h is projected from both sides of the outer surface of the seal block 6. and grooves 74. 76 and 78 are formed on the outer surface of the seal block 6. and the groove 76 are communicated through a hole 80 between the gears 2 and 3. Side plates 82 are provided at both side surfaces of the seal block 6 in such a manner that clearance t is provided between the peripheral surface 82a ofthe side plates 82 and the collar 611.
  • a gear pump or motor having a housing including an inner and outer surface and at least two ports communicating between the interior and exterior thereof providing an inlet and outlet for the pump or motor; a pair of gears engaging each other within a portion of said housing; and a seal block disposed within said housing between the inner surface of the housing at the high pressure side thereof and the teeth ends of the gears wherein said seal block includes a first passage communicating between the portion of said housing occupied by said gears and one of said ports; a plurality of pressure chambers formed between the inner surface of said housing and said seal block; and a plurality of second passages formed between said pressure chambers and the portion of the housing occupied by said gears at the periphery of the gears spaced from the high pressure engagement area of the gears.
  • seal block comprises a seal block body having holes formed therethrough, and a plate having a plurality of pressure chambers opposite to said holes of said seal block body in contact with the outer surface of said seal block body.

Abstract

A gear pump and motor having a housing, a pair of gears engaged with each other, and a seal block disposed between the inner surface of the housing at high pressure side and the teeth ends of the gears, which has the seal block having a passage formed therethrough for hydraulic oil, a plurality of pressure chambers formed between the inner surface of the housing and the seal block, and a plurality of holes or passage are formed in the seal block for communicating the pressure chamber with the gear side. Thus, it prevents hydraulic oil from leaking to provide a high efficient gear pump and motor.

Description

United States Patent 1191 Futamata et a1.
1451 Oct. 1, 1974 THE GEARS Inventors: Masayuki Futamata, Tokyo; Takao Nukada; Yasuo Kitta; Koiti Morita; Kazuyuki Hirose, all of Yokohama, Japan Assignee:
Filed:
Kabushiki Kaisha Komatsu Seisakusho, Tokyo, Japan Dec. 21, 1972 Appl. No.: 317,707
Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 1,058,153 4/1913 Clark 418/71 3,472,170 10/1969 Eckerle 418/126 Primary Examiner-John .1. Vrablik Attorney, Agent, or Firm-Armstrong, Nikaido & Wegner 5 7 ABSTRACT A gear pump and motor having a housing, a pair of gears engaged with each other, and a seal block disposed between the inner surface olf the housing at high pressure side and the teeth ends of the gears, which has the seal block having a passage formed therethrough for hydraulic oil, a plurality of pressure cham- Jan. 24, 1972 Japan 47-8272 betS formed between the inner Sui-fa:e of the housing 24, 1972 Japan t 47-9552 and the seal block, and a plurality of holes or passage 1972 Japan 47953 are formed in the seal block for communicating the Jan. 24, Japan t 1 pressure chamber gear ide Thus prevents hydraulic oil from leaking to provide a high efficient UaS- Cl. gear pump and motor Int. Cl. F011: 19/02, F03c 3/00, F04c 15/00 Field 01 Search 418/71, 125, 126, 129 7 Claims, 27 Drawlng Figures PMENTE BBT mm mm W PRIOR ART GEAR PUMP AND MOTOR HAVING A SEALED LOCK FOR PREVENTING HYDRAULIC OIL FROM LEAKING BETWEEN THE ENDS OF THE TEETH OF THE GEARS This invention relates to a gear pump and motor. and more particularly to improve gear pump and motor having a seal block for preventing hydraulic oil from leaking between the teeth ends of the gears.
In the conventional gear pump and motor. a drive gear and a driven gear are engaged in mesh with each other in a housing, and for example. when this gear pump and motor is used as a pump, fluid is intaken from an inlet by means of the rotation of the drive and driven gears. and is fed out from an outlet as high pressure (when the gear pump and motor is used as a motor, fluid intaking side becomes high pressure). In order to prevent gap or clearance from being produced at the ends of the gears at high pressure side and to lessen the area for hearing high pressure fluid, in such type of gear pump and motor, a seal block is so disposed that the teeth ends of the drive and driven gears are contacted with each other in the housing at high pressure side.
However, since the conventional seal block of the gear pump and motor is symmetrical with respect to the engaging center of the drive and driven gears, the pressure distribution of hydraulic fluid for acting onto the surface of the seal block contacting with the drive and driven gears is different at the drive side and at the driven side in every half pitch of the gears. For this reason, the seal block vibrates, or one contacting portion of the seal block with the gear is worn so that the seal block is displaced to one side. Thus, it is impossible to obtain stable sealing of the teeth ends of the gears of the gear pump and motor.
More particularly, when the contacting conditions of the contacting portions of the seal block with the teeth ends of the drive and driven gears are different at the drive side and at the driven side, the pressure distribution of hydraulic fluid for acting onto the contacting portion of the seal block at the drive side and the pressure distribution of hydraulic fluid for acting onto the contacting portion of the seal block at the driven side are different with the result that one hydraulic pressure becomes higher than the other hydraulic pressure so that there takes place a couple of forces that overall the seal block rotates along the outer periphery of the seal block. Therefore, the contacting of the teeth ends of the gear with the contacting portion of low pressure side becomes stronger than the other with the result that one side is worn as its disadvantage.
Further, since the width of the seal block is made equal to the width of the gears in the conventional gear pump and motor so that the longitudinal movement of the seal block is affected only by the hydraulic force. if the urging force of the seal block onto the gears is strong, the seal block is gradually worn by means of the contacting with the teeth ends of the gears.
This invention contemplates to eliminate the aforementioned disadvantages of the conventional gear pump and motor, and to provide an improved gear pump and motor.
It is an object of the present invention to provide a gear pump and motor which may always maintain the contacting of the teeth ends of the gears with the seal block so as to prevent high hydraulic pressure fluid from leaking from the teeth ends of the gears.
It is another object of the present invention to provide a gear pump and motor which may not vibrate the seal block so as to obtain stable sealing of the teeth ends of the gears.
It is a further object of the present invention to provide a gear pump and motor which may prevent the variation of the seal block.
It is still another object of the present invention to provide a gear pump and motor which may easily produce a pressure chamber so as to improve the accuracy thereof.
It is still another object of the present invention to provide a gear pump and motor which may improve the endurance thereof.
It is still another object of the present invention to provide a gear pump and motor which may easily balance the hydraulic pressure of the seal block.
One characteristic feature of the present invention is a gear pump and motor having a housing. a pair of gears engaged with each other, and a seal block disposed between the inner surface of the housing at high pressure side and the teeth ends of the gears, which comprises the seal block having a passage formed therethrough for hydraulic oil a plurality of pressure chambers formed between the inner surface of the housing and the seal block. and a plurality of holes formed in the seal block for communicating the pressure chamber with the gear side.
These and other objects, features and advantages of the present invention will becomes apparent from the following description taken in conjunction with the accompanying drawings. in which:
FIG. 1 is a longitudinal sectional view of the conventional gear pump and motor;
FIG. 2 is a schematic view of the conventional gear pump and motor for explanatory purpose;
FIG. 3 is a longitudinal sectional view of the gear pump and motor of the present invention;
FIG. 4 is a sectional view of the gear pump and motor taken along the line IV IV in FIG. 3;
FIG. 5 is an enlarged perspective view of one embodiment of the seal block used in the present invention;
FIG. 6 is a side view of the seal block showing the state of the pressure distribution acting onto the seal block;
FIG. 7 is a side view of another embodiment of the seal block used in the present invention;
FIG. 8 is a side view of a further embodiment of the seal block used in the present invention;
FIG. 9 is a back view of the seal block shown in FIG. 8;
FIG. 10 is a sectional view of another embodiment of the gear pump and motor of the present invention;
FIG. 11 is an enlarged partial view at the part XI in FIG. 10;
FIG. 12 is an enlarged partial view at the part XII in FIG. 10;
FIG. 13 is a longitudinal sectional view of the essential part of a further embodiment of the present invention;
FIG. 14 is a plan view of the plate used in this invention;
FIG. I5 is a sectional viewof the plate taken along the line XV XV in FIG. 14;
FIG. 16 is a longitudinal sectional view of still another embodiment of the present invention;
FIG. 17 is a front view of the essential part of the present invention;
FIG. 18 is a sectional view taken along the line XVIII XVIII in FIG. I7;
FIG. 19 is a perspective view of the seal plate used in the present invention;
FIG. 20 is a plan view of still another embodiment of the seal plate used in the present invention;
FIG. 21 is a sectional view of the seal plate taken along the line XXI XXI in FIG. 20;
FIG. 22 is a sectional view of the seal plate taken along the line XXII XXII in FIG. 20;
FIG. 23 is a schematic view of the seal plate used in the present invention for the explanatory purpose;
FIG. 24 is a side view partially omitted of still another embodiment of the present invention;
FIG. 25 is a schematic view of the essential part of the device shown in FIG. 24-;
FIG. 26 is a sectional view taken along the line XXVI XXVI in FIG. 25;
FIG. 27 is a view seen in the direction by an arrow XXVII in FIG. 26.
For the better understanding of the present invention, the conventional gear pump and motor will now be described with reference to FIGS. I and 2.
As shown in FIG. I, in the conventional gear pump and motor, a drive gear 2 and a driven gear 3 are engaged in mesh with each other in a housing I, and for example, in the event that this gear pump and motor is used as a pump, fluid is intaken from an inlet 4 by means of the rotation of the drive and driven gears 2 and 3, and is fed out from an outlet 5 as high pressure (when the gear pump and motor is used as a motor, fluid intaking side becomes high pressure). In order to prevent gap or clearance from being produced at the ends of the gears 2 and 3 at high pressure side and to lessen the area for bearing high pressure fluid in such type of gear pump and motor, a seal block 6 is so disposed that the teeth ends of the drive and driven gears 2 and 3 are contacted with each other in the housing I at high pressure side.
However. since the conventional seal block 6 of the gear pump and motor is symmetrical with respect to the engaging center of the drive and driven gears 2 and 3 as shown in FIG. 1, the pressure distribution of hydraulic fluid for acting onto the surfaces 6a and 6b of the seal block 6 contacting the drive and driven gears 2 and 3 is different at the drive side and at the driven side in every half pitch of the gears 2 and 3, as shown in FIG. 6. Therefore, the seal block 6 vibrates, or one contacting portion 6a or 6b of the seal block with the gear is worn so that the seal block 6 is displaced to one side. Thus, it is impossible to obtain stable sealing of the teeth ends of the gears 2 and 3 of the gear pump and motor.
Further, when the contacting conditions of the contacting portions 6a and 6b of the seal block 6 with the teeth ends of the drive and driven gears 2 and 3 are different at the drive'side and the driven side. the pressure distrubution of hydraulic fluid for acting onto the contacting portion of the seal block 6 at the drive side and the pressure distrubution of hydraulic fluid for acting onto the contacting portion of the seal block 6 at the driven side are different with the result that one hydraulic pressure becomes higher than the other hydraulic pressure so that there takes place a couple of forces that overall the seal block 6 rotates along the outer periphery of the seal block 6. Therefore. the contacting of the teeth ends of the gear with the contacting portion of low pressure side becomes stronger than the other with the result that one side is worn.
Then. since the width of the seal block 6 is made equal to the width of the gears 2 and 3 in the conventional gear pump and motor as shown in FIG. 2 so that the longitudinal movement of the seal block 6 is affected only by the hydraulic force. if the urging force of the seal block 6 onto the gears is strong. the seal block 6 is gradually worn by means of the contacting with the teeth ends of the gears 2 and 3.
Reference is now made to FIGS. 3 to 5. which show one embodiment of the gear pump and motor of the present invention.
A seal block 6 is disposed between the inner surface 8 of a housing 1 at high pressure side and the teeth ends 10 and 12 of gears 2 and 3 engaged with each other. and has a chamber 14 formed therethrough for hydraulic oil. and pressure chambers I6 are formed between the inner surface 8 of the housing 1 and the seal block 6. Holes or passages 18 are formed in the seal block 6 for communicating the pressure chamber 16 with the gear side.
The seal block 6 is so formed as to be the same width that of the gears 2 and 3. and the housing is composed of a body 1a and a cover Ib connected by bolts 20. Numeral 22 represents an inlet, and 24 represents an outlet. Seal rubbers 34 and backup plates 36 are provided in the pressure chamber 16 for preventing high pressure hydraulic oil from leaking from the contacting surfaces of the inner surface 8 of the housing 1 and the seal block 6. The drive gear 2 is journalled with a drive shaft 26, and the driven gear 3 is journalled with a driven shaft 28. The shafts 26 and 28 are rotatably mounted to the housing I through bearings 30. Numeral 32 represents circular side plates which are disposed between the gears 2, 3 both ends of the seal block 6 and the inner surface of the housing 1, respectively. A hole 38 is formed in the side plate 32 to communicate with the chamber 14. The side plate 32 is always urged in contact with the gears 2 and 3 and the both ends of the seal block 6 by high pressure hydraulic oil introduced between the inner surface of the housing I and the side plate 32, that is, by the hydraulic pressure in the chamber 14, so as to prevent the hydraulic oil from leaking from the gears 2 and 3 and both ends of the seal block 6. In the drawings, movable type side plate (push type) is shown, but stationary type side plate may also be used within the scope of this invention.
It should be understood from the foregoing description that since the pressure chamber 16 is formed at the seal block 6 to be communicated with the gear side through the holes 18 as this is used as a pump, the seal block 6 is always urged in the direction to contact with the teeth ends 10 and 12 of the gears 2 and 3 by the discharge pressure of the hydraulic oil at high pressure side, and even if the discharge pressure becomes high so that the gears 2 and 3 are moved to low pressure side or intake side in case of pump, since the seal block 6 moves followed by the movement of the gears 2 and 3, the contacting of the teeth ends 10 and 12 of the gears 2 and 3 with the seal block 6 may be always kept constant, and accordingly it is possible to prevent high pressure fluid from leaking from the teeth ends 10 of the gears 2 and 3. Further, since it has less part acting with the high pressure. it is possible to reduce the hearing load at the same time to reduce the thickness of the housing.
Referring now to FIGS. 6 and 7, another embodiment of the seal block used in the gear pump and motor of the present invention will now be described.
As shown in FIG. 7, the seal block 6 is so formed as to be asymmetrical with respect to the engaging center of the gears 2 and 3 in such a manner that the contacting portions 6c and 6d of the seal block 6 with the gears 2 and 3, respectively are displaced by half pitch of the gears in circumferential direction of one gear. However, the length of arcuate of the contacting portions 6c and 6d are equal, and its length is slightly longer than the length of one pitch of the gear plus the width of the teeth ends.
Thus, the contacting state of the contacting portion 60 of the seal block 6 and the drive gear 2 becomes the same as the contacting state of the contacting portion 6d of the seal block 6 and the driven gear 3 so that the pressure distrubution acting onto the contacting portions 60 and 6d becomes equal, as shown in FIG. 7. This pressure distrubution is varied as the teeth ends moves, but becomes equal at both contacting portions 60 and 6d.
It should be understood that since the contacting portions 60 and 6d of the seal block 6 are displaced by half pitch of the gear in phase at the drive side and at the driven side, the pressure acting onto both contacting portions 6c and 6d becomes equal, and accordingly the seal block does not vibrate, nor a couple of forces act to the seal block 6, but the seal block is held in stationary state thereby providing always stable sealing of the teeth ends.
Reference is now made to FIGS. 8 and 9, which show a further embodiment of the seal block used in the gear pump and motor of the present invention. As shown in FIG. 8, holes 42a and 42b are formed from the contacting portions 6a and 6b of the seal block 6 toward the center of the seal block 6 in such a manner that both holes 42a and 42b are crossed at their ends so as to communicate the contacting portions 6a and 6b with the holes 42a and 42b. The opened position of the holes 1 42a and 421; are symmetrically disposed at the contacting portions 6a and 6b of the seal block 6, and are disposed substantially intermediate in arcuate direction of the contacting portions. And, as shown in FIG. 9, the lateral position of the holes 420 and 42b are any place at right and left position of the passage 14 of the seal block 6.
Thus, the contacting portion 6a contacting with the drive gear 2 and the contacting portion 6b contacting with the driven gear 3 are communicated with each other through the holes or passages 42a and 42b so that the pressure acting onto the contacting portions 6a and 6b of the seal block 6 becomes equal.
Although the holes 42a and 42b are formed in the seal block 6 in the above embodiment, they may be formed on the side surface of the seal block 6 as grooves so as to communicate with the contacting portions 6a and 612, or grooves may be provided on the side plate 32. In this case, it is necessary that both side surfaces must be cut to form grooves so that the thrust force may not act onto the seal block 6.
It should be understood that since both the contact ing portions 6a and 6b of the seal block 6 with the gears 2 and 3 are communicated with each other by the holes 42a and 42b, the pressure distribution acting onto both contacting portions 6a and 6b becomes equal. and accordingly a couple of forces may not act onto the seal block 6, but stable sealing of the seal block 6 with the teeth ends of the gears 2 and 3 may be conducted.
Referring now to FIGS. 10 and 12, which show still another embodiment of the gear pump and motor of the present invention, on the outer surface of the seal block 6 are formed pressure chambers 16a, 16b and I60. The center pressure chamber 16b is communicated between the gears 2 and 3 through the passage I4, and a stepped portion 44 is formed at the opening of the pressure chamber 1612 at the passage 14, and a collar 46 is engaged at the outlet 22 of the housing 1 to be inserted into the stepped portion 44 so as to from a throttle 48 with the collar 46 and the stepped portion 44. The pressure chambers 16a and 160 are communicated between the gears 2 and 3 through holes 18a and 181;, respectively, and throttles 50 and 52 are formed at the holes 180 and 18h, respectively. O-rings 54 are engaged with the pressure chambers 16a, 16b and 16c to be urged onto the inner peripheral surfaces of the housing 1.
When the seal block 6 moves in X direction, the volume of the pressure chambers 16a, 16b and 16c becomes smaller,'and accordingly the hydraulic oil tends to flow through the throttles 50, 48 and 52 and holes 18a, 14 and 18b toward the gear side. but the hydraulic pressure in the pressure chambers 16a, 16b and 160 becomes higher than the pressure at the gear side by the flow resistance of the trottles 50, 48 and 52 so as to pre vent the seal block 6 from moving in X direction.
On the other hand, when the seal block 6 moves in X direction, the volume of the pressure chambers 16a, 16b, and 16c becomes larger, and accordingly the hydraulic oil tends to flow from the gear side through the V holes 18a, 14 and 18b toward the pressure chambers 16a, 16b and 16c. and therefore. the hydraulic pressure at the gear side becomes lower than the pressure of the pressure chambers 16a, 16b and [Ge so as to prevent the seal block 6 from moving in X direction.
It should be understood that since the throttles 50, 48 and 52 are provided in the holes 18a, 14 and 18b for communicating the pressure chambers 16a, 16b and 160 on the outer surface of the seal block 6 between the gears 2 and 3, the force of restitution takes place in the direction opposite to the moving direction of the seal block 6 against the movement of the seal block 6, and accordingly the variation of the seal block may be prevented.
Referring now to FIGS. 13 to 15., which show still another embodiment of the gear pump and motor of the present invention, the seal block 6 is composed of a seal block body 6c and a plate 6f. More particularly, the seal block body 6c has holes 18a, 14 and 18b therethrough, and the plate 6f also has holes 56, 58 and 60 and is bent along the outer surface of the seal block body 6c. This plate 6f is so disposed in the housing 1 as to be superimposed on the outer surface of the seal block body 6e in such a manner that the holes 56, 58 and 60 form pressure chambers 116a, 16b and together with the outer surface of the seal block body 60. O-ring 54 are disposed in the pressure chambers 16a, 16b and 16c.
FIG. 16 shows still another embodiment of the gear pump and motor of this invention, and the pressure chambers 16a, 16b and 160 are formed on the inner surface of the plate 6ftogether with the outer contacting surface of the seal block 6, and a hole 62 is formed in the pressure chatnher 16/) at the center thereof. and the outer surface of the plate 6/ is slidingly contacted with the inner peripheral surface of the housing I.
It should be understood that since the seal block 6 is composed of the seal block body 6e having the holes 18a, l4 and 180, and the plate 6f having the pressure chambers 16a, 16b and 16c opposite to the holes 18a, 14 and 18b in contact with the outer surface of the seal block body 62, and accordingly the plate 6]" is simply constructed in such a manner that only holes are formed at the plate and the plate 6f is bent along the outer surface of the seal block body 6e, the pressure chambers are very easily formed so as to improve the accuracy thereof.
Reference is now made to FIGS. 17 to 23, which show still another embodiment of the gear pump and motor of the present invention.
In this embodiment, the pressure chambers 16a, 16b and 160 are formed on the outer surface of the seal block 6, and are communicated between the gears 2 and 3 through the holes 18a, 14 and 18b. As shown in FIG. 17, these pressure chambers 16a, 16b and 160 have the same length of the width as the width of the seal block 6, and seal plates 64 of the same length as the total length of the pressure chambers 16a and 160 are engaged slidably in the pressure chambers 16a and 16c. As shown in FIGS. 20 to 22, the seal plate 64 may have a recess 66 at the inside surface, or as shown in FIG. 19, it may be of planar shape. A seal plate 70 formed with a hole 68 therethrough is slidably engaged at the center in the pressure chamber 16b.
In such a structure, hydraulic oil between the gears 2 and 3 acts to the pressure chambers 16a, 16b and 160 through the holes 18a, 14 and 18b with the result that the seal plates 64 and 70 are urged onto the inner peripheral surfaces of the housing 1. At this time, the seal block 6 is moved laterally of the drawing, and there are produced gaps between the seal block 6 and the inner peripheral surface of the housing 1, and accordingly high pressure hydraulic oil tends to flow to the end surfaces 6g of the seal block 6 from the gap of the pressure chambers 16a, 16b and 160, but since the end surfaces 6g are urged by the side plates 32, the hydraulic oil cannot flow out therefrom.
It should be understood that since the present invention comprises the seal block 6 formed with the pressure chambers 16a, 16b and 160 having the same length as the width of the seal block on the outer surface thereof, seal plates 64 having the same length as the length of the pressure chambers 16a, and 160 and slidably engaged with the pressure chambers l6a, and 16c, seal plate 70 having the same length as the length of the pressure chamber 16/), and a hole 68 at the center thereof and slidably engaged with the pressure chamber 16b, and side plates 32 contact at both ends of the seal plates 64 and 70, the pressure chamber may be formed along all the width of the seal block in comparison with the pressure chamber containing the O-rings and backup rings as the foregoing embodiment so that the working is easy so as to provide easily accuracy, and since the seal plate is used instead of O-ring, its breakage is less so as to improve its endurability.
Referring now to FIGS. 24 to 27, which show still another embodiment of the gear pump and motor of the present invention, collar 6h is projected from both sides of the outer surface of the seal block 6. and grooves 74. 76 and 78 are formed on the outer surface of the seal block 6. and the groove 76 are communicated through a hole 80 between the gears 2 and 3. Side plates 82 are provided at both side surfaces of the seal block 6 in such a manner that clearance t is provided between the peripheral surface 82a ofthe side plates 82 and the collar 611.
When the gear side 6/ of the seal block 6 is contacted with the teeth ends of the gears 2 and 3 to be worn. the collar 6/1 contacts with the peripheral surface 82a of the side plate 6 so that the seal block 6 does not move to the gear 2 and 3 side so as to prevent the seal block 6 from wearing.
It should be understood that since the collar 6/1 is formed on both sides of the outer surface of the seal block 6 so that clearance r is provided between the pe ripheral surface 82a of the side plates 82 disposed at both sides of the seal block 6 and the collar 6/2. the wear by the contact of the seal block 6 with the gears 2 and 3 is prevented by contacting the collar 6/2 with the side plates 82 so as to improve the endurability and it is easy to provide hydraulic balance of the seal block.
What is claimed is:
1. A gear pump or motor having a housing including an inner and outer surface and at least two ports communicating between the interior and exterior thereof providing an inlet and outlet for the pump or motor; a pair of gears engaging each other within a portion of said housing; and a seal block disposed within said housing between the inner surface of the housing at the high pressure side thereof and the teeth ends of the gears wherein said seal block includes a first passage communicating between the portion of said housing occupied by said gears and one of said ports; a plurality of pressure chambers formed between the inner surface of said housing and said seal block; and a plurality of second passages formed between said pressure chambers and the portion of the housing occupied by said gears at the periphery of the gears spaced from the high pressure engagement area of the gears.
2. A gear pump or motor as set forth in claim 1, wherein a portion of said seal block facing one of said gears is displaced by half the pitch of said gears in the circumferential direction with respect to a portion of said seal block facing the other of said gears.
3. A gear pump or motor as set forth in claim 1, wherein said plurality of pressure chambers comprise three pressure chambers, the center of the three pres sure chambers communicates between the gears through a passage, and a stepped portion is formed at the opening of said center pressure chamber at said passage, and wherein a collar is engaged at the outlet of said housing, said collar being inserted into the stepped portion to form a throttle therewith. and wherein the side pressure chambers communicate between the gears through holes in which throttles are formed, and wherein O-rings are engaged with the pressure chambers.
4. A gear pump or motor as set forth in claim 1, wherein said seal block comprises a seal block body having holes formed therethrough, and a plate having a plurality of pressure chambers opposite to said holes of said seal block body in contact with the outer surface of said seal block body.
eluding a collar projecting from both sides of the outer surface of said seal block. and side plates provided at both side surfaces of said seal block in such a manner that clearance is provided between the peripheral surface of the side plates and the collar.
7. A gear pump or motor as set forth in claim I wherein at least one third passage :is formed in said seal block between said pressure chambers.

Claims (7)

1. A gear pump or motor having a housing including an inner and outer surface and at least two ports communicating between the interior and exterior thereof providing an inlet and outlet for the pump or motor; a pair of gears engaging each other within a portion of said housing; and a seal block disposed within said housing between the inner surface of the housing at the high pressure side thereof and the teeth ends of the gears wherein said seal block includes a first passage communicating between the portion of said housing occupied by said gears and one of said ports; a plurality of pressure chambers formed between the inner surface of said housing and said seal block; and a plurality of second passages formed between said pressure chambers and the portion of the housing occupied by said gears at the periphery of the gears spaced from the high pressurE engagement area of the gears.
2. A gear pump or motor as set forth in claim 1, wherein a portion of said seal block facing one of said gears is displaced by half the pitch of said gears in the circumferential direction with respect to a portion of said seal block facing the other of said gears.
3. A gear pump or motor as set forth in claim 1, wherein said plurality of pressure chambers comprise three pressure chambers, the center of the three pressure chambers communicates between the gears through a passage, and a stepped portion is formed at the opening of said center pressure chamber at said passage, and wherein a collar is engaged at the outlet of said housing, said collar being inserted into the stepped portion to form a throttle therewith, and wherein the side pressure chambers communicate between the gears through holes in which throttles are formed, and wherein O-rings are engaged with the pressure chambers.
4. A gear pump or motor as set forth in claim 1, wherein said seal block comprises a seal block body having holes formed therethrough, and a plate having a plurality of pressure chambers opposite to said holes of said seal block body in contact with the outer surface of said seal block body.
5. A gear pump or motor as set forth in claim 1, wherein said pressure chambers have the same the width as the width of said seal block with seal plates of the same length as the total length of said pressure chambers engaged slidably in said pressure chambers and wherein a seal plate is formed with a hole therethrough slidably engaged at the center in an intermediate pressure chamber of said plurality of pressure chambers.
6. A gear pump or motor as set forth in claim 1, including a collar projecting from both sides of the outer surface of said seal block, and side plates provided at both side surfaces of said seal block in such a manner that clearance is provided between the peripheral surface of the side plates and the collar.
7. A gear pump or motor as set forth in claim 1 wherein at least one third passage is formed in said seal block between said pressure chambers.
US00317707A 1972-01-17 1972-12-21 Gear pump and motor having a sealed lock for preventing hydraulic oil from leaking between the ends of the teeth of the gears Expired - Lifetime US3838952A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP827272U JPS4884014U (en) 1972-01-17 1972-01-17
JP955572U JPS4887606U (en) 1972-01-24 1972-01-24
JP955372U JPS4887605U (en) 1972-01-24 1972-01-24
JP955272U JPS4887604U (en) 1972-01-24 1972-01-24

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Cited By (6)

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US3915604A (en) * 1973-04-20 1975-10-28 Komatsu Mfg Co Ltd Seal block device for use in oil hydraulic gear pump
US3995975A (en) * 1974-03-27 1976-12-07 Robert Bosch G.M.B.H. Gear pump
EP0216999A2 (en) * 1985-09-29 1987-04-08 Anqiang Cheng An external gear pump or gear motor unit of the asymmetric radial floating type
US6167980B1 (en) 1998-06-05 2001-01-02 Caterpillar S.A.R.L. Engine mounting and stabilizing arrangement
US20040155118A1 (en) * 2003-02-11 2004-08-12 Rice Charles J. Fluid pump
US10933496B2 (en) 2018-10-15 2021-03-02 Caterpillar Inc. Repair of cast iron bore inner diameter surfaces

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DE2411492C2 (en) * 1974-03-11 1984-07-26 Robert Bosch Gmbh, 7000 Stuttgart Gear pump
FR2324905A1 (en) * 1975-09-19 1977-04-15 Retel J R Gear pump wear take-up device - has insert at outlet with central passage and seal ring on face adjacent housing
DE2604969A1 (en) * 1976-02-09 1977-08-11 Eckerle Otto Gear pump or motor with two hears - has curved sealing plates for sensitive adjustment of seal pressure
US4336005A (en) * 1979-04-13 1982-06-22 Tyrone Hydraulics, Inc. Gear pumps and motors
DE3023710A1 (en) * 1980-06-25 1982-01-14 Heinz Mendoza Loos Gear type hydraulic pump - has pressure adjusting cowl resting on centre rest plates in casing ends to reduce wear
DE3211726A1 (en) * 1981-03-31 1983-02-03 Kayabakogyokabushikikaisha, Tokyo SEALING BLOCK FOR GEAR PUMPS OR MOTORS
CN106640643A (en) * 2016-11-16 2017-05-10 天津商业大学 Screw refrigerating compressor with variable angle contact seal

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US1058153A (en) * 1909-05-26 1913-04-08 Standard Gear Motor Company Rotary engine.
US3472170A (en) * 1965-10-12 1969-10-14 Otto Eckerle High pressure gear pump or motor with compensation for play and wear

Patent Citations (2)

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Publication number Priority date Publication date Assignee Title
US1058153A (en) * 1909-05-26 1913-04-08 Standard Gear Motor Company Rotary engine.
US3472170A (en) * 1965-10-12 1969-10-14 Otto Eckerle High pressure gear pump or motor with compensation for play and wear

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3915604A (en) * 1973-04-20 1975-10-28 Komatsu Mfg Co Ltd Seal block device for use in oil hydraulic gear pump
US3995975A (en) * 1974-03-27 1976-12-07 Robert Bosch G.M.B.H. Gear pump
EP0216999A2 (en) * 1985-09-29 1987-04-08 Anqiang Cheng An external gear pump or gear motor unit of the asymmetric radial floating type
EP0216999A3 (en) * 1985-09-29 1988-07-20 Anqiang Cheng An external gear pump or gear motor unit of the asymmetric radial floating type
US6167980B1 (en) 1998-06-05 2001-01-02 Caterpillar S.A.R.L. Engine mounting and stabilizing arrangement
US20040155118A1 (en) * 2003-02-11 2004-08-12 Rice Charles J. Fluid pump
US6808121B2 (en) * 2003-02-11 2004-10-26 Charles J. Rice Fluid pump
US10933496B2 (en) 2018-10-15 2021-03-02 Caterpillar Inc. Repair of cast iron bore inner diameter surfaces

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