CN201368025Y

CN201368025Y - Improved structure of screw stem vacuum pump

Info

Publication number: CN201368025Y
Application number: CNU2009201156365U
Authority: CN
Inventors: 陈海垚; 梁伯顺; 周法顺; 李万友
Original assignee: TAIZHOU XINGGUANG VACUUM EQUIPMENT CO Ltd
Current assignee: TAIZHOU XINGGUANG VACUUM EQUIPMENT CO Ltd
Priority date: 2009-03-16
Filing date: 2009-03-16
Publication date: 2009-12-23
Anticipated expiration: 2019-03-16

Abstract

The utility model relates to vacuum acquiring equipment, in particular to a variable pitch dry-type screw stem vacuum pump which is an improved structure of the screw stem vacuum pump; the structure comprises a shell (3), two ends of the shell (3) are respectively provided with end covers, an end cover (2) is manufactured with an air suction port (1), an end cover (6) is manufactured with an air exhaust port (13), at least two screw stem pairs are arranged in the shell (3), and a driving shaft (8) and a driven shaft (11) are formed, the thread pitch and tooth form depth of each screw stem pair are gradually reduced along the axial direction from the air suction port (1) to the air exhaust port (13). The structure leads a product to have low power consumption and obtain high pumping speed and high vacuum degree, the processing and manufacturing are easy, the reliability is high and the service life is long, and the structure integrates the advantages of a uniform-pitch structure and a variable pitch structure and avoids the disadvantages of the uniform-pitch structure and the variable pitch structure, the cost performance is high.

Description

The improvement structure of screw vacuum pump

Technical field:

The utility model relates to pumping equipment, particularly a kind of variable pitch dry screw vacuum pump.

Background technique:

Advantages such as screw vacuum pump has and do not have oily, simple in structure, few easy workout part, maintenance load is little, the life-span is long, environmentally friendly.The conventional screw vacuum pump divides two kinds on uniform pitch structure and variable pitch structure, and the uniform pitch structure has relatively easier advantage of processing; The shortcoming that exists is: consumed power is big, and the exhaust pulsation is big, not steady, and is big etc. in the identical situation lower volume of air displacement and compression ratio; Advantages such as it is little that the variable pitch structure has consumed power, and exhaust is steady, shortcoming are difficulties of manufacturing.

The model utility content:

The purpose of this utility model is to overcome the above-mentioned shortcoming that prior art exists and improvement structure that a kind of screw vacuum pump is provided.

A kind of improved screw vacuum pump structure of the utility model, comprise housing, end cap is equipped with at the two ends of housing respectively, end cap is shaped on intakeport, end cap is shaped on relief opening, in housing, be provided with at least two screw pairs, and be formed on a driving shaft and the driven shaft, it is characterized in that pitch and the depth of profile from suction port to each screw pair of relief opening axial direction successively decreases.

Described each screw pair itself is uniform pitch basically.

Described each screw pair itself is to wait tooth depth basically.

The external diameter of described each screw pair from suction port to the relief opening axial direction successively decreases, corresponding to corresponding the successively decreasing of external diameter at the housing position of each screw pair.

The profile of tooth cross section of described screw pair is trapezoidal that a right angle side is arranged.

Be provided with valve between described per two screw pairs, valve is loaded on the top of housing, communicates with relief opening by outlet pipe.

Adopting interference fit to be connected near the screw pair of suction port and the connection of axle, all the other screw pairs adopt ringfeder to be connected with axle.

Described housing outer wall is made heat radiating fin structure.

The utility model adopts constant lead screw auxiliary structure more than two sections or two sections, the pitch and the spiral degree of depth are all dwindled to the exhaust side direction from air inlet side, can make the product consumed power little, exhaust is steady, can obtain bigger pumping speed and the degree of vacuum of Geng Gao, manufacturing is easy, the reliability height, long service life combines the advantage of uniform pitch structure and variable pitch structure, avoided the shortcoming of the two to greatest extent, the cost performance height.

Description of drawings:

Fig. 1 is the utility model embodiment vertical section structure figure.

Fig. 2 is an A-A sectional view among Fig. 1.

Description of symbols among the figure: suction port 1, end cap 2, housing 3, radiating fin 31, interlayer 32, valve 4, outlet pipe 5, end cap 6, driving gear 7, driving shaft 8, the dark tooth screw pair 9 of large screw pitch, fine pitch shallow flight screw pair 10, driven shaft 11, driven gear 12, relief opening 13, valve pocket 14.

Embodiment:

With reference to Fig. 1, Fig. 2, end cap 2 is equipped with at the two ends of embodiment's housing 3 respectively, and driving shaft 8 and driven shaft 11 are equipped with driving gear 7 and driven gear 12 separately and are supported on end cap 2; Left end cap is shaped on suction port 1, right end cap is shaped on relief opening 13, in housing 3, be provided with at least two screw pairs, pitch and depth of profile from suction port to each screw pair of relief opening axial direction successively decrease, be that dark tooth screw pair 9 of large screw pitch and fine pitch shallow flight screw pair 10 are solidly set on driving shaft 8 and the driven shaft 11 from left to right successively, wherein each screw pair itself is uniform pitch and tooth depth such as grade basically; The connection of the dark tooth screw pair 9 of large screw pitch and driving shaft 8 and driven shaft 11 adopts interference fit to be connected, and fine pitch shallow flight screw secondary 10 adopts ringfeder to be connected with driving shaft 8 with driven shaft 11.The front end of the dark tooth screw pair 9 of large screw pitch is communicated with suction port 1, and secondary 10 tail ends of fine pitch shallow flight screw are communicated with relief opening 13.The profile of tooth cross section of each screw pair is trapezoidal that a right angle side is arranged.The design of the depth of each screw pair tooth depth will be according to the good engagement of active screw rod and driven screw rod, the external diameter from suction port to the relief opening axial direction successively decreases with each screw pair during design, the external diameter that is fine pitch shallow flight screw pair 10 is less than the dark tooth screw pair 9 of large screw pitch, correspondingly, the external diameter corresponding to the housing position of each screw pair successively decreases.

Between dark tooth screw pair 9 of large screw pitch and secondary 10 jointing places of fine pitch shallow flight screw, leave valve pocket 14, in valve pocket 14 upper ends valve 4 is set, valve 4 is loaded on the top of housing 3, communicate with relief opening 13 by outlet pipe 5, when cavity 14 internal pressures surpass barometric pressure, valve 4 is backed down, and a part of gas is through the dark tooth screw pair 9 of large screw pitch, outlet pipe 5 straight-through relief opening 13 dischargings; When valve pocket 14 internal pressures are equal to or less than barometric pressure, valve 4 is fallen by deadweight and closes, and leads to relief opening 13 dischargings through fine pitch shallow flight screw pair 10, and the pitch of screw pair 10 equates in addition, relief opening 13 air-flows are more stable, so the power of necessary electromotor can be smaller.

Because two screw rods makes the pumped gas compression ratio increase in running, temperature rises very fast, so housing 3 makes radiating structure, promptly is shaped on interlayer 32 in housing 3, and cooling liquid can circulate in the interlayer.For guaranteeing better heat radiating effect, housing 3 outer walls are shaped on radiating fin 31, with the cooling of the cooling liquid in the interlayer, guarantee that the screw pump temperature is in the operating temperature range all the time.

Claims

1, a kind of improved screw vacuum pump structure, comprise housing (3), end cap is equipped with at housing (3) two ends respectively, end cap (2) is shaped on intakeport (1), end cap (6) is shaped on relief opening (13), in housing (3), be provided with at least two screw pairs, and be formed on a driving shaft (8) and the driven shaft (11), it is characterized in that pitch and the depth of profile from suction port (1) to relief opening (13) each screw pair of axial direction successively decreases.

2,, it is characterized in that each screw pair itself is uniform pitch basically according to the described improved screw vacuum pump structure of claim 1.

3,, it is characterized in that each screw pair itself is to wait tooth depth basically according to the described improved screw vacuum pump structure of claim 1.

4,, it is characterized in that the external diameter from suction port (1) to relief opening (13) each screw pair of axial direction successively decreases, corresponding to corresponding the successively decreasing of external diameter at housing (3) position of each screw pair according to the described improved screw vacuum pump structure of claim 1.

5, according to claim 1 or 2 or 3 or 4 described improved screw vacuum pump structures, the profile of tooth cross section that it is characterized in that described screw pair is trapezoidal that a right angle side is arranged.

6, according to the described improved screw vacuum pump structure of claim 1, it is characterized in that being provided with valve (4) between described per two screw pairs, valve (4) is loaded on the top of housing (3), communicates with relief opening (13) by outlet pipe (5).

7, according to the described improved screw vacuum pump structure of claim 1, it is characterized in that adopting interference fit to be connected near the screw pair (9) of suction port (1) and the connection of axle, all the other screw pairs adopt ringfeder to be connected with axle.

8,, it is characterized in that housing (3) outer wall makes heat radiating fin structure according to the described improved screw vacuum pump of claim 1.