CN201448241U

CN201448241U - Annular balance piston

Info

Publication number: CN201448241U
Application number: CN2009200458813U
Authority: CN
Inventors: 许吉清; 曹勤良; 张国强; 周耘
Original assignee: Wuxi Compressor Co Ltd
Current assignee: Wuxi Compressor Co Ltd
Priority date: 2009-05-12
Filing date: 2009-05-12
Publication date: 2010-05-05
Anticipated expiration: 2019-05-12

Abstract

The utility model provides an annular balance piston used inside a bearing support at an air discharge end of an oil-injected screw compressor. An annular groove is arranged on the outer circumference of the piston, a piston ring is movably arranged inside the annular groove, and the outer diameter is larger than that of the piston. By arranging the annular groove on the outer circumference of the piston and movably disposing the piston ring inside the annular groove, gaps exist between the annular groove and the piston ring. When the annular balance piston is used, the piston ring is tightly engaged with an inner cavity of a rotor bearing support, thereby eliminating radial gaps between the piston and the bearing support. Besides, pressure oil flows from the gaps between the annular groove and the piston ring, thereby pressure inside a pressure cavity of the bearing support is guaranteed easily.

Description

Annular balancing piston

(1) technical field

The utility model relates to a kind of annular balancing piston, is specially a kind of equalizing piston that is used in the fuel injection helical lobe compressor exhaust end bearing support.

(2) background technique

Fuel injection helical lobe compressor because of the structural feature of rotor helical-screw shape, in the process of engagement compression, axially can produce thrust at rotor when load operation.In order to reduce of the influence of this end thrust to bearing, improve the working life of bearing, generally in the exhaust end bearing support of compressor, add equalizing piston.

The equalizing piston structure of existing fuel injection helical lobe compressor is made up of the pressure oil cavity A and the low pressure bearing bore B on rotor shaft bearing 4, equalizing piston 3 and equalizing piston 3 both sides as shown in Figure 1.Among the figure, 1 is angular contact ball bearing, and 2 is roller bearing, and 5 is compressor drum.Form certain pressure when time among the pressure oil injection pressure oil pocket A, pressure oil flows into low pressure bearing bore B by the gap between equalizing piston 3 and the rotor shaft bearing 4 then.Owing between two chambeies of A, B certain pressure difference is arranged, has formed the equilibrant opposite, thereby reduced the stressed of compressor shaft axial thrust bearing, the life-span of having improved thrust-bearing with the rotor axial thrust direction.

There is following problem in above-mentioned equalizing piston structure:

1, the radial clearance between equalizing piston 3 and the rotor shaft bearing 4 is bigger, and a large amount of pressure oil runs off by this gap, and it is not high that the pressure reduction on equalizing piston 3 both sides is carried, and equilibrant is little.

2, the manufacturing tolerances of the cylindrical of the endoporus of rotor shaft bearing 4 and equalizing piston 3 is bigger to the area effect of the annular that forms between them, makes the oil mass that flows through bearing change greatly, and is difficult to control.

(3) model utility content

The utility model provides a kind of annular balancing piston at the problems referred to above, and this piston can increase its equilibrant after being used for the exhaust end bearing support of fuel injection helical lobe compressor.

The technical solution of the utility model is such: a kind of annular balancing piston is characterized in that: the excircle of described piston is provided with annular groove, and head has piston ring in the annular groove, and the external diameter of piston ring is greater than the external diameter of piston.

The further technological scheme of the utility model is: the piston external diameter of described annular groove both sides is unequal, is stepped shape; Described piston ring is provided with opening; The plane of described piston ring both sides is provided with the contract groove; The position of the contract groove of described piston ring both sides is corresponding; The quantity of the contract groove of described each side of piston ring is four; Described contract groove is uniform on the plane of piston ring both sides; The cross section of described contract groove is a V-arrangement.

The outer peripheral surface of the utility model piston is provided with annular groove, head has piston ring in the annular groove, therefore there is the gap between annular groove and the piston ring, drive fit between piston ring and rotor shaft bearing inner chamber during use, can eliminate the radial clearance between piston and the bearing support, pressure oil flows out by the gap between annular groove and the piston ring, and the pressure in the bearing support pressure chamber guarantees that easily equilibrant is bigger than equilibrium structure of the prior art.

The utility model piston ring is provided with contract groove and opening, and the size of contract groove and opening is control easily all, therefore controls easily by the oil mass of bearing.

(4) description of drawings

Fig. 1 is the schematic representation of existing equalizing piston structure;

Fig. 2 is for using the partial structurtes sectional view of compressor of the present utility model;

Fig. 3 is the sectional view of the piston in the utility model;

Fig. 4 is the plan view of the piston ring in the utility model;

Fig. 5 is the C-C sectional view among Fig. 4;

Fig. 6 is the D place enlarged view among Fig. 5.

(5) embodiment

See Fig. 2, be to use the partial structurtes of a kind of fuel injection helical lobe compressor of the present utility model.Compressor drum 5 is assemblied on the rotor shaft bearing 4, is equipped with the roller bearing 2 of bearing radial force and the angular contact ball bearing 1 of bearing axial pushing force on the spindle nose of compressor drum 5 side by side.On the axle body of the compressor drum 5 between roller bearing 2 and rotor shaft bearing 4 sidewalls, be equipped with equalizing piston 3.Equalizing piston 3 is divided into two chambeies with the space between roller bearing 2 and rotor shaft bearing 4 sidewalls, is respectively pressure oil cavity A and low pressure bearing bore B.

The utility model is the improvement to the structure of above-mentioned equalizing piston 3.The excircle of piston 3 is provided with annular groove 8, and head has piston ring 6 in the annular groove 8, that is to say between annular groove 8 and the piston ring 6 to have the gap between piston ring 6 and the piston 3 slide relative is arranged.The external diameter of piston ring 6 is greater than the external diameter of piston 3, and during work, piston ring 6 is fitted with rotor shaft bearing 4 inner chambers under the effect of elastic force and frictional force and do not changeed.Piston ring 6 has been filled the radial clearance between piston 3 and the bearing support 4, and pressure oil flows out by the gap between annular groove 8 and the piston ring 6, and the pressure in the bearing support pressure chamber A guarantees that easily equilibrant is bigger than equilibrium structure of the prior art.

As shown in Figure 3, piston 3 external diameters of annular groove 8 both sides can be arranged to unequal, are stepped shape.During installation, big external diameter 7 is close to low pressure bearing bore B in low voltage side, can increase the area of contact of piston 3 and piston ring 6, reduces the specific contact pressure of piston 3 and piston ring 6; Little external diameter 9 is in the high pressure side, and contiguous pressure oil cavity A helps the installation of piston ring 6, and piston ring 6 is as long as very little amount of deformation just can be enclosed within on the piston 3.

As Fig. 4～shown in Figure 6, piston ring 6 is provided with opening 11; The corresponding section, position is provided with contract groove 10 on the plane of piston ring 6 both sides.Contract groove 10 is uniform on the plane of piston ring 6 both sides; The quantity of the contract groove 10 of each side is four or other quantity; The sectional shape of contract groove 10 can be circular arc, U-shaped, but is preferably V-arrangement.Owing to have V-arrangement contract groove 10 on piston ring 6, the contract oil groove of similar plain thrust bearing makes between piston 3 and the piston ring 6 and forms oil film, and the pressure oil in the pressure oil cavity A can only flow to low pressure bearing bore B by contract groove 10 on the piston ring 6 and opening 11.Therefore the size of contract groove 10 and opening 11 is control easily all, and the oil mass that enters low pressure bearing bore B from pressure oil cavity A is controlled easily.

Working principle of the present utility model is: the pressure difference of pressure oil cavity A and low pressure bearing bore B acts on piston 3 and the piston ring 6, the direction of the axial force F 2 that the direction of the axial force F 1 that forms and rotor 5 are suffered is opposite, and axial force F 1 has played the effect of balance portion axial force F 2.

Claims

1. annular balancing piston, it is characterized in that: the excircle of described piston is provided with annular groove, and head has piston ring in the annular groove, and the external diameter of piston ring is greater than the external diameter of piston.

2. annular balancing piston according to claim 1 is characterized in that: the piston external diameter of described annular groove both sides is unequal, is stepped shape.

3. annular balancing piston according to claim 1 is characterized in that: described piston ring is provided with opening.

4. annular balancing piston according to claim 1 is characterized in that: the plane of described piston ring both sides is provided with the contract groove.

5. annular balancing piston according to claim 4 is characterized in that: the position of the contract groove of described piston ring both sides is corresponding.

6. annular balancing piston according to claim 5 is characterized in that: the quantity of the contract groove of described each side of piston ring is four.

7. annular balancing piston according to claim 4 is characterized in that: described contract groove is uniform on the plane of piston ring both sides.

8. annular balancing piston according to claim 4 is characterized in that: the cross section of described contract groove is a V-arrangement.