Adjustable gear-type pump. RU patent 2511848.

FIELD: engines and pumps.

SUBSTANCE: invention relates to power engineering, and namely to volumetric hydraulic machines of adjustable capacity. An adjustable gear-type pump of external engagement with axial movement of one of pump gears 5 includes a pair of end bandages 6 and 7 with internal teeth arranged in cavities of pump gears 4 and 5, and contactless seals 13 and 14. Seals 13 and 14 are gear-type and fixed on end faces of gears 4 and 5 located inside bandages 6 and 7. Teeth of seals 13 and 14 are arranged in cavities of internal teeth of bandages 6 and 7. Their modules, gaps and number of teeth are made as per certain expressions.

EFFECT: increasing volumetric efficiency owing to reducing leakage volume of pumped fluid via reduced gaps between teeth of end bandages and pump gears.

2 dwg

The invention relates to the mechanical engineering industry, in particular to volumetric hydraulic machines adjustable performance. The invention may be applied in industrial hydraulic drives, including the transmission hydromechanical transmission and transport traction machines, and also in various sectors related to the processing and use of oil products for manufacturing processes.

Known hydraulic devices that use a gear pump with continuously adjustable performance by changing the depth of engagement pumping gear metering gears without changing displacement pump (see EN 2404386 C1, 20.11.2010, F16H39/42).

The essence of such pumps are characterized by a selection of necessary doses of a working body between areas of suction and discharge pipes. Selection, that is, transfusion or bypass discharge of fluid from the field into the suction is applied on gear and other volumetric pumps with constant displacement and small power. This way of controlling the feed of uneconomical, as part of the power developed by the pump, is lost in the valve, made in the form of dosing gears. Another disadvantage of such a hydraulic devices is that the selection reduces the degree of liquid filling depressions between the gear teeth. Incomplete filling depressions causes premature wear of gears, pulsating load on gear pump cavitation under different modes of its work, which excludes its application in the transmission hydromechanical transmission vehicles, including, and for automotive transmissions.

A more economical way to regulate the supply of hydraulic pump, from the point of view of consumption, is a way to change its working volume.

Known adjustable gear pump, in which a smooth change its supply is achieved by changing its working volume (see SU 709834, 15.01.1980, F04C 2/08). The pump contains a body with inlet and outlet channels, pumping gear with their shanks. Leading pump gear is situated between their cylinder liners, planted on her shanks for boarding slip and motionless relative to the housing of the pump. One of stationary liners, such as Nizhny, is equipped with the segment's boring, and the other, the upper input and output channels. Driven pumping gear is situated between his cylindrical floaters planted on her shanks for boarding slip and with the possibility of axial displacement relative to the pinion teeth and body. One of the slides, for example, top, equipped with radial boring with the possibility of placing in it the top liner leading pumping gear, and the other, the lower cylindrical slide made with the possibility for accommodation in segmented groove bottom liner pinion. The pump capacity modulation is achieved axial displacement unit driven pumping gear together with its floaters in adequate openings on the device. When the top drawer location driven gear working volume of the pump takes the maximum value, as its length is maximum equal to the width of the pumping gear for maximum performance. At the bottom drawer location driven pumping gear working volume of the pump takes the minimal value, as its length is approaching zero, which provides a minimum capacity of the pump. The drawback of this pump is that when working on the intermediate partial regimes are formed camera harmful space volume with rajubhai driven gear and the same amount from under the teeth of the pinion. Therefore, the total amount of the two chambers of harmful space equals 2C. Ignoring the elastic deformation of the walls of the working chamber from the pressure of the fluid, the expression for theoretical volumetric efficiency about ETA for the pump will have the form (see Basta T.M. displacement pumps and hydraulic motors hydraulic systems. M: Engineering, 1974).

where p n - output pressure of the pump;? - coefficient of volumetric compression; q is the volume of one of the working cavity of the pump gear. From the expression (1), partial operation modes of the pump with the presence of the volume 2c harmful space theoretical coefficient of n about the pump is significantly reduced.

Pump with low efficiency at partial regimes cannot be recommended for practical use, for example for the transmission of road transport. In these conditions the internal combustion engine works with increased fuel consumption, especially in urban traffic and negatively affects the ecology of the environment.

For the prototype accepted gear pump with capacity regulation due to the axial movement driven pumping gear leading pump gear. The pump on the prototype volume 2C of harmful spaces are eliminated by placing the inner teeth of the end of the cylinders in the hollows of pump gears (see SU 399626, 03.10.73, F04C 2/04).

The pump allows to reduce leakage of the fluid from his working cavity by reduction of radial clearance only for heads of internal teeth end of the cylinder, for which it is supplied with sealing washers are installed inside face of the cylinder at the ends pumping gear. The pump on the prototype has the following disadvantages.

1. Sealing washers are non-contact seals that are not eliminate the gaps between the sealing surfaces, and only reduce them, it inevitably leaked pumped liquid. Such seals are used as a first stage is intended for pressure reduction before a contact seal.

2. Sealing washers in the prototype reduce the gaps between heads of internal teeth end of the cylinder and the grounds depressions gears. The gaps between the lateral surfaces of the teeth the end of the cylinder and associated with lateral surfaces of the teeth pump gears remain completely open. Open also remain gaps between the pump casing and the heads of pumping gear. Under these gaps leakage of fluid obtained significant, which excludes the effectiveness of the pump on the prototype in transmissions of road transport.

The task of the new development provides creation of the regulated gear pumps by axial displacement of the inner teeth of front tyres on depressions pumping gear with minimal clearance between the inner teeth of front tyres and outer teeth pumping gear.

The problem is solved by the fact that the minimum clearances between adjacent teeth are provided around the perimeter of the cross-section of teeth pump gears, including the width of their heads, depressions and lateral surfaces.

The technical result of the decision of a task is the increase of volumetric efficiency gear pumps due to the lower volume of leakage of the fluid in the reduced gaps between the teeth of front tyres and pumping gear.

The above technical result is achieved in the following way. Adjustable gear external gear pump with axial displacement of one pump gears, containing a pair of front tyres with internal teeth placed in the hollows of pump gears, and non-contact seals in which non-contact seals made gear and attached to the ends of the gears inside the tyres, and the teeth of the seals placed in the hollows of internal teeth bandages, as their modules and gaps established by the following expression:

where m Shu - module gear sealer;

m NSH - module pumping gear;

C - gaps:

C su - between the head of the tooth sealant and hollow tooth band;

C GSH - between the head of tooth gears and pumping cavity of the tooth band;

C Woo - between the cavity of the tooth sealant and head of the tooth band;

C HS - between the cavity of the tooth pumping gear and head of the tooth band;

C BU - backlash gear seal;

H BSH - side gap pumping gear;

z , z, W is the number of teeth of the pinion seals and pump gear.

The use of gear seal with dimensions of expressions (2) substantially reduce the gaps around the perimeter of the tooth pump gears, reducing leakage of the fluid and improves volumetric efficiency leading pump.

The possibility of the implementation of the present invention to provide the above technical results are illustrated by the drawings.

Figure 1 shows the regulated gear pump in longitudinal section; figure 2 shows the fragment transverse type of pump in section A-A in figure 1.

In building 1 gear pumps placed his flanges 2 and 3, a leading pump gear 4 and coupled with her slave pump gear 5, a pair of front tyres 6 and 7, the inner teeth of which is placed in the hollows of pump gears 4 and 5, and the input 8 hole and output 9 for the pumped liquid.

Band 6 planted in adequate hole slide 10 planting slip, and its shaft is fixed in the small of his hole lock 11 with the possibility of a fixed rotation in the holes of the slide 10. Band 7 seated in adequate housing bore 1 with the possibility of rotation and fixed it flange 2 for exceptions axial movement. Located in the band 7, pumping gear 5 enshrined in the hole of the slide 10 lock 12 with the possibility of rotation around its axis. At the ends of the pump gears 4 and 5, located in bandages 6 and 7, fixed gear non-contact seals 13 and 14 using fasteners such as screws 15 and 16. Teeth sealants 13 and 14 placed in the hollows of internal teeth tyres 6 and 7 with clearances C se C Boo , Z. Wu , who fewer gaps teeth pump gears C GSH , C slams , C HS (Figure 2). Minimum clearances C se , BU C , C vu is provided by known methods, such as grinding of teeth sealants 13, 14 relevant to the tooth tyres 6, 7; and the use of selective Assembly. If you need to use the smallest gaps and to achieve an increased hermeticity valid application gear seals 13 and 14, executed in the form of the famous floating rings.

Leading pump gear 4, rotating together with sealant 13 and tyre 6, rotate driven pumping gear 5 together with sealant 14 and tyre 7. At rotation of pump gears 4, 5 in the entrance channel 8 will create a vacuum, and in the output 9 - pressure that provides the required flow rate of the fluid.

The liquid flow smoothly when moving driven gear 5 jointly with consolidation of 14, slide 10 through the use of the drive, including the threads in the slide 10, screw 18 and gearbox engine 17. Minimum volume of the pumped liquid is accomplished with a working length l p =l n , and the maximum value is in its length, for example, l, R =-2l n , where In - the width of the tooth pumping gear.

The proposed gear pump smaller gaps and leakage of liquid on them, which increases its volumetric efficiency.

So, for example, modeling of gaps and areas using computer-aided design systems "COMPASS-3D" for the regulated gear pumps involute-with teeth initial data:

- outside diameter surface heads gear d d =100 mm,

- diameter dividing the circumference d=80 mm,

- diameter of a circle depressions d =60 mm,

- number of teeth z=6 mm,

- gaps between elements gear and adequate elements of a toothed band accepted by the expression Z GSH =C slams ,=C vs =0.5 mm

- the gap between the outside diameter of the seal of the prototype and heads of internal teeth bandage is taken Z UE =0.25 mm,

- the gap between the outside diameter of the seal on the invention and heads of internal teeth band C ia =0.25 mm,

showed the following results.

The area f and gaps in the invention in 1,89 times less space f p gaps prototype, so we offer adjustable pump has an increased tightness.

Leakage Q and gaps in the pump the invention in 7,28 times less leakage Q p on gaps in the pump on the prototype, so the pump has increased volumetric efficiency.

Adjustable gear external gear pump with axial displacement of one pump gears, containing a pair face tyres with internal teeth placed in the hollows of pump gears, and non-contact seals, wherein non-contact seals made gear and attached to the ends of the gears inside the tyres, and the teeth of the seals placed in the hollows internal teeth bands, and their modules, gaps and number of teeth are installed by the following expressions:

Shu - module gear seal;

NSH - module pumping gear;

C - gaps:

su - between the head of the tooth sealant and hollow tooth band;

GSH - between the head of tooth gears and pumping cavity of the tooth band;

Wu - between the cavity of the tooth sealant and head of the tooth band;

HS - between the cavity of the tooth pumping gear and head of the tooth band;

Boo backlash gear seal;

BSH - side gap pumping gear;

W - number of teeth of the pinion seal and pump gear.