US3420180A

US3420180A - Gear pump

Info

Publication number: US3420180A
Application number: US655216A
Authority: US
Inventors: Bertwin E Behrends; James L Schmitt
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1967-07-21
Filing date: 1967-07-21
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07
Also published as: FR1575023A

Description

United States Patent O 2 Claims ABSTRACT F THE DISCLOSURE A gear pump having a pair of interengaging gears rotatable in a chamber, two inlet ports for admitting uid from two separate sources and in a set ratio into the chamber, each of the gear wheels serving to impel uid from one of the sources toward an outlet port, the uid from the two inlet ports being combined at the outlet port.

Gear pumps usually include two inter-engageable gear wheels which rotate in a pump chamber. The two wheels serve to draw fluid from a single chamber inlet port and to expel it through a chamber outlet port. Gear pumps have often been employed for purposes in which it is desirable to pump fluids from two separate sources. Where gear pumps have been so used, it has usually `been necessary to employ two pumps, each connected to one of the separate sources. Such use of two pumps has presented disadvantages, both with respect to increased costs and increased space requirements.

Attempts have been made to direct the fluid from the two separate sources into the inlet port of a single pump. This fails to provide an adequate degree of control over the pumping operation. In particular, it has not been possible to pump the uids from the separate sources in a fixed ratio. Since the uids pumped may differ in resistance to the pump suction, an undesirably large proportion of one fluid may be pumped as compared to the amount of the other fluid being pumped.

Gear pumps have been employed for pumping cooling oil to the brakes of an automotive vehicle such as a tractor. The oil employed has often been drawn from the torque converter scavenge sump of the vehicle. Such oil has not always provided adequate cooling of the 'brakes when overheated. It has, therefore, been considered desirable to provide cooling oil in a xed ratio `from two separate sources. The cost of providing additional cooling oil has been prohibitive because of the need for a second pump and the provision of space for two pumps.

The present invention is designed to overcome the above discussed problems of the prior art. The advantages of the invention will become apparent to one skilled in the art trom the following description when read in conjunction with the accompanying drawing which is a medial cross sectional fview of a pump constructed in accordance with the invention.

In the drawing, there is shown a gear pump which embodies the present invention. The pump 10 provides a housing 12 which denes a chamber 14. The chamber 14 has an outlet port 16.

Mounted within the chamber 14 are a pair of

gears

20 and 22. Each of the

gears

20 and 22 has teeth 24 which define cavities 25 therebetween. The gear 20 is rotatable in a clockwise direction while the gear 22 is rotatable in a counterclockwise direction. The gears are positioned for inter-engagement of their teeth approximately at the center of the chamber 14. The teeth 24, when disengaged, pass in close proximity to the wall surface 26 of the chamber 14.

Two

inlet ports

32 and 34 are disposed at opposite sides of the chamber 14.

In order that more lluid will be drawn by the pump through one inlet than through the other, an inlet ratio bypass passageway is provided at 36. It extends between inlet passage 32, as at 38, to a point 40 in the gear chamber upstream of the point where inlet 34 enters.

In the operation of the pump 10, fluid from a first source enters the chamber 14 through the passageway 32. Such fluid is impelled by the rotating gear 20 through the chamber 14 and through the outlet port 16.

Fluid from a second source similarly enters the chamber 14 through the inlet passageway 34. This uid is impelled by the gear 22 toward and through the outlet port 16. Because of the bypass 36, some uid from inlet 32 ows to gear 22 and is propelled by it toward the outlet. This reduces the capacity of gear 22 to receive and transfer uid from inlet 34.

The bypass or ratio-change passageway 36 provides a means for increasing the amount of fluid admitted from the passageway 32 as compared to the amount of fluid admitted from the passageway 34. The size of the passageway is designed to provide the desired ratio of ow from two sources and the ratio will remain substantially constant at different pump speeds since the pump is of bsometric design between each inlet and the outlet.

The pump may be employed yfor such purposes as the provision of cooling oil to the brakes of a tractor. It might thus be -used to scavenge the torque converter by sucking oil and air from the latter through the inlet passageway 34. At the same time, oil from a separate reservoir might be drawn through the inlet passageway 32. Such separate reservoir might, for example, be the bevel gear case sump. The oil from the two sources would then be combined at the outlet 16 in a set ratio for use for brake cooling purposes.

The use of the pump provides savings in both cost and space requirements as compared to the use of two separate pumps for pumping the uids from the two separate sources.

We claim:

1. A gear pump comprising:

(a) a housing defining a chamber having a iluid outlet port;

(b) a pair of inter-meshing -gears rotatable in said chamber and each adapted to impel uid toward said outlet port;

(c) means defining a rst fluid inlet port for said chamber and being adapted to introduce fluid between the teeth of one of said gears; and

(d) means defining a second iiud inlet port for said chamber and being adapted to introduce iiuid between the teeth of the other of said gears, said inlet ports being located at opposite sides respectively of said chamber, means to increase the rate 0f flow of uid introduced Ibetween the teeth of one of said gears as compared to the rate of flow of fluid introduced between the teeth of the other of said gears, said means comprising a ratio-change passageway arranged to receive tluid from one inlet passageway and to direct it to the gear adjacent the other inlet passageway.

3 4 2. A pump in accordance with claim 1 in which the 2,944,487 7/ 1960 Walsh 103-7 passageway directs uid to the gear prior to the direc- 3,018,641 1/ 1962 Carpigiani. tion of uid thereto by said other passageway. 3,080,819 3/ 1963 Mayes.

3,137,137 6/1964 Klle ..-103-7 X References Cited 5 3,242,867 3/1966 Mosbacher 103--126 X 1 631 591 FTES PATENTS 103 7 DONLEY J. STOCKING, Primary Examiner.

1 1,687,523 10/1928 Stande. WARREN J. KRAUSS, ASSSaZ Examiner. 1,902,346 3/1933 Vogt. 2,301,496 11/1942 Aldrich 10s-2X 10 103 126 7 U-S- Cl- X-R- 2,820,416 1/ 1958 Compton.