A Roots vacuum pump with high reliability gear transmission

Abstract

The utility model relates to a Roots vacuum pump with high-reliability gear transmission, which includes a pump body, a set of double-cone expansion rings between the synchronous gear and the rotor shaft, the double-cone expansion rings include an inner cone sleeve, an intermediate cone sleeve and an outer cone sleeve sequentially sleeved from the inside to the outside, the outer sleeve of the rotor shaft is sleeved with an inner cone sleeve, the outer cone sleeve is sleeved on the inner ring of the synchronous gear, an intermediate cone sleeve is arranged between the inner cone sleeve and the outer cone sleeve, and the intermediate cone sleeve is fastened by inserting a set screw. The utility model reduces the repeated positioning of the gear structure, is conducive to adjusting the meshing clearance between the rotors, thereby facilitating assembly and maintenance, improving work efficiency, and reducing assembly and maintenance costs.

Description

Technical Field

[0001] The utility model relates to the technical field of Roots vacuum pumps, in particular to a Roots vacuum pump with high-reliability gear transmission. Background Art

[0002] Roots vacuum pump is a rotary positive displacement vacuum pump that uses two "8" shaped rotors to rotate in the housing to produce suction and exhaust. At present, the large and medium-sized Roots vacuum pumps on the market have the following problems: complex gear structure, poor positioning accuracy, poor interchangeability, cumbersome assembly and disassembly, especially the inability to adjust the meshing clearance between the two rotors by radial displacement of the gears. The existing internal connection structure of the Roots vacuum pump gear can be found in Figure 1 , mainly composed of: air inlet, exhaust port, pump body, front and rear end covers, rotor, synchronous gear, bearing, labyrinth seal, front cover, rear cover, coupling, motor connecting frame, motor, etc. A pair of three-leaf involute rotors are arranged horizontally and parallel inside the pump body. Two rotor shafts 10 are supported and fixed in the front and rear end covers by four bearings in the front and rear end covers respectively. Four sets of labyrinth seal structures are arranged in the front and rear end covers to isolate the mutual interference between the pumped gas and the lubricating oil in the front and rear covers; a mechanical seal structure is arranged at the shaft end of the main shaft, and the motor provides torque to the active rotor through the coupling. The active rotor makes the active rotor and the driven rotor mesh with each other with a certain gap in the pump body through a pair of synchronous gears in the rear cover and rotate in the synchronous direction to continuously complete the vacuum process of suction and exhaust.

[0003] See also Figure 2 The present invention is a diagram of the internal connection structure of the existing Roots vacuum pump gear pair. The synchronous gear is paired with a driving gear and a driven gear with the same module and the same number of teeth in a transmission ratio of 1:. Figure 3 This is a partial cross-sectional view of the synchronous gear. The driving gear is installed on the shaft end on one side of the driving rotor of the Roots vacuum pump, and the driven gear is installed on the shaft end on the side of the driven rotor. The driving and driven gears are composed of a gear ring, a gear housing, a taper pin, a connecting bolt, a flat washer, an elastic washer, a round nut, a thrust washer, a flat key, etc. The inner hole of the gear ring of the driving and driven gears is assembled with the outer circle of the gear housing and fixed by a set of hexagonal bolts and washers. The two taper pins are used for radial positioning of the gear ring and gear housing and for transmitting torque. The power of the driving and driven rotors transmits torque through this pair of synchronous gears in the gear oil tank.

[0004] The gear transmission of the existing Roots vacuum pump has the following problems: the gear ring and the gear housing are connected and transmit torque through a conical pin, and the gear housing and the shaft are connected and transmit torque through a flat key. Once the clearance between the rotors does not meet the design requirements after assembly or long-term operation of the vacuum pump, it is impossible to adjust the meshing clearance between the rotors by a simple method. When assembling the gears, the meshing clearance of a pair of rotors must be measured first, the position of the locating pin hole must be confirmed, and then the gears must be disassembled, and the locating pin holes must be punched on a special machine tool, and the locating pins must be installed. Then, the gears must be assembled to the shaft end of the rotor. If the rotor meshing clearance is inaccurate, the driven gear must be disassembled and the conical pin holes must be re-drilled to adjust the clearance, which makes assembly and maintenance time-consuming and labor-intensive, with low efficiency, and high assembly and maintenance costs. Due to the defects in the gear structure design, many difficulties in assembly and maintenance are caused, especially since the user site generally does not have mechanical processing equipment. Once the vacuum pump needs to adjust the meshing clearance between the rotors, it will encounter maintenance difficulties.

[0005] Therefore, a Roots vacuum pump with high-reliability gear transmission is needed to solve the above problems. Summary of the invention

[0006] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide a Roots vacuum pump with a high-reliability gear transmission, which reduces the repeated positioning of the gear structure, improves the accuracy of the gear transmission, reduces the temperature rise of the gear, prolongs the service life of the gear, and is conducive to adjusting the meshing clearance between the rotors, thereby facilitating assembly and maintenance and improving work efficiency.

[0007] The purpose of the utility model is achieved in this way:

[0008] A Roots vacuum pump with high-reliability gear transmission, comprising a pump body, wherein the front end of the pump body is provided with a front cover, the rear end is provided with a rear cover, the front end cover is provided with a front cover, and the rear end cover is provided with a rear cover; a pair of three-leaf involute rotors which are parallel, horizontally installed and meshed with each other are provided in the pump body: a driving rotor and a driven rotor, the driving rotor is arranged on a main shaft, and the driven rotor is arranged on a rotor shaft, the main shaft and the rotor shaft are arranged in the pump body, a synchronous gear is provided in the rear cover, and the synchronous gear is sleeved on the end of the main shaft; the driving rotor and the driven rotor are caused to rotate synchronously and at a constant speed in the pump body through a pair of synchronous gears in an oil tank; the driving rotor and the driven rotor are respectively installed in the front end cover and the rear end cover at both ends of the pump body through bearings;

[0009] A set of double-conical expansion rings is provided between the synchronous gear and the rotor shaft, and the double-conical expansion ring includes an inner conical sleeve, an intermediate conical sleeve and an outer conical sleeve which are sequentially sleeved from the inside to the outside. The outer sleeve of the rotor shaft is sleeved with an inner conical sleeve, and the outer conical sleeve is sleeved on the inner ring of the synchronous gear. An intermediate conical sleeve is provided between the inner conical sleeve and the outer conical sleeve, and the intermediate conical sleeve is fastened by inserting a set screw.

[0010] Furthermore, the outer wall of the inner cone sleeve is provided with two outer cone surfaces which are symmetrical to each other, and the inner wall of the outer cone sleeve is provided with two inner cone surfaces which are symmetrical to each other, and the inner cone sleeve and the outer cone sleeve are symmetrically arranged with respect to the middle cone sleeve.

[0011] Furthermore, the middle cone sleeve is in a circular ring shape, with its outer ring being provided with an outer chaser matching the outer cone sleeve, and its inner ring being provided with an inner cone surface matching the inner cone sleeve, and at least two fixing screws being provided inside the circular ring of the middle cone sleeve for fastening the connection.

[0012] Furthermore, the taper of the inner cone sleeve, the middle cone sleeve and the outer cone sleeve is 1:20, and the tapers of the inner cone sleeve, the middle cone sleeve and the outer cone sleeve are kept consistent.

[0013] Furthermore, the shaft end of the main shaft extends out of the front cover and is connected to a coupling, and the coupling is connected to the motor.

[0014] Furthermore, a piston ring labyrinth seal is provided at the connection between the rear end of the main shaft and the rear end cover.

[0015] Furthermore, a mechanical seal is provided at the connection between the front end of the main shaft and the front end cover.

[0016] Furthermore, an air inlet is provided at the upper end of the pump body, and an air outlet is provided at the lower end.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] The utility model provides a Roots vacuum pump with high-reliability gear transmission. The gear transmission adopts an expansion sleeve connection transmission. A pair of expansion sleeves with inner and outer conical surfaces fitting together are placed between the shaft and the gear. The expansion sleeve has a simple structure, high reliability and strong load-bearing capacity. Under the action of the pre-tightening force of the high-strength bolt, the inner ring shrinks and the outer ring expands, so that the inner ring and the shaft, the outer ring and the gear fit closely, and a sufficiently large friction force is generated to transmit torque. The utility model is very suitable for adjusting the meshing clearance between rotors of the Roots vacuum pump. The utility model reduces repeated positioning of the gear structure, improves the accuracy of the gear transmission, reduces the temperature rise of the gear, prolongs the service life of the gear, and is conducive to adjusting the meshing clearance between the rotors, thereby facilitating assembly and maintenance, improving work efficiency and reducing the cost of assembly and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the internal connection diagram of the gears of an existing Roots vacuum pump.

[0020] Figure 2 This is the internal connection diagram of the gear pair of an existing Roots vacuum pump.

[0021] Figure 3 It is a structural schematic diagram of the utility model.

[0022] Figure 4 for Figure 3 A partial enlarged view of point A.

[0023] Figure 5 It is a schematic structural diagram of the double cone expansion ring gear of the utility model.

[0024] in:

[0025] Pump body 1, air inlet 1.1, exhaust port 1.2, rear end cover 2, rear cover 3, front end cover 4, front cover 5, synchronous gear 6, double cone expansion ring 7, inner cone sleeve 7.1, middle cone sleeve 7.2, outer cone sleeve 7.3, set screw 7.4, bearing 8, rotor 9, rotor shaft 10, coupling 11, motor 12. DETAILED DESCRIPTION

[0026] In order to better understand the technical solution of the present invention, the following will be described in detail in conjunction with the relevant illustrations. It should be understood that the following specific embodiments are not intended to limit the specific implementation of the technical solution of the present invention, and are only implementations that can be adopted by the technical solution of the present invention. It should be noted that the description of the positional relationship of each component in this article, such as component A being located above component B, is based on the description of the relative positions of the components in the illustration, and is not intended to limit the actual positional relationship of the components. Example 1

[0027] See also Figure 1-Figure 5 , Figure 3 The structural schematic diagram of the utility model is drawn. As shown in the figure, a Roots vacuum pump with high reliability gear transmission includes a pump body 1, the front end of the pump body 1 is provided with a front cover 4, the rear end is provided with a rear cover 2, the front cover 4 is provided with a front cover 5, and the rear cover 2 is provided with a rear cover 3; the pump body 1 is provided with a pair of parallel horizontally installed and mutually meshing three-leaf involute rotors 9: an active rotor and a driven rotor, the active rotor is installed on the main shaft, and the driven rotor is installed on the rotor shaft 10, the main shaft and the rotor shaft 10 are arranged in the pump body 1, and the active rotor and the driven rotor are respectively installed in the front cover 2 and the rear cover 4 at both ends of the pump body through bearings 8; the rear cover 5 is provided with a synchronous gear 6, and the synchronous gear 6 is sleeved on the end of the main shaft; the active rotor and the driven rotor make the rotor 9 rotate synchronously and at a constant speed in the pump body 1 through a pair of synchronous gears 6 in the oil tank.

[0028] A set of double-conical expansion rings 7 is provided between the synchronous gear 6 and the rotor shaft 10. The double-conical expansion ring 7 includes an inner cone sleeve 7.1, an intermediate cone sleeve 7.2 and an outer cone sleeve 7.3 which are sequentially sleeved from the inside to the outside. The outer part of the rotor shaft 10 is sleeved with the inner cone sleeve 7.1. The outer cone sleeve 7.3 is sleeved on the inner ring of the synchronous gear 6. An intermediate cone sleeve 7.2 is provided between the inner cone sleeve 7.1 and the outer cone sleeve 7.3. The intermediate cone sleeve 7.2 is fastened by inserting a set screw 7.4.

[0029] The outer wall of the inner cone sleeve 7.1 is provided with two outer cone surfaces which are symmetrical on the left and right, the inner wall of the outer cone sleeve 7.3 is provided with two inner cone surfaces which are symmetrical on the left and right, the inner cone sleeve 7.1 and the outer cone sleeve 7.3 are symmetrically arranged about the middle cone sleeve 7.2; the middle cone sleeve 7.2 is in a circular ring shape, and its outer ring is provided with an outer ring which matches the outer cone sleeve 7.3, and its inner ring is provided with an inner cone surface which matches the inner cone sleeve 7.1, and no less than two fixing screws 7.4 are provided in the circular ring of the middle cone sleeve 7.2 for fastening connection.

[0030] The taper of the inner cone sleeve 7.1, the middle cone sleeve 7.2 and the outer cone sleeve 7.3 is 1:20, with a large contact area and good load-bearing capacity; and the tapers of the inner cone sleeve 7.1, the middle cone sleeve 7.2 and the outer cone sleeve 7.3 must be kept consistent in order to achieve the best connection effect.

[0031] The inner cone sleeve 7.1, the middle cone sleeve 7.2 and the outer cone sleeve 7.3 have high precision requirements to ensure their smoothness and precision and avoid interference and deviation.

[0032] The shaft end of the main shaft extends out of the front cover 5 and is connected to the coupling 11 , and the coupling 11 is connected to the motor 12 ; a coupling protective cover is provided outside the coupling 11 .

[0033] A piston ring labyrinth seal is provided at the connection between the rear end of the main shaft and the rear end cover 2 , and a mechanical seal is provided at the connection between the front end of the main shaft and the front end cover 4 .

[0034] The pump body 1 is provided with an air inlet 1.1 at the upper end and an air outlet 1.2 at the lower end.

[0035] Working principle:

[0036] The utility model discloses a Roots vacuum pump with high-reliability gear transmission. A pair of expansion sleeves with inner and outer conical surfaces fitting together are placed between a shaft and a gear. When connecting, the inner conical sleeve is firstly put on the shaft, and then the outer conical sleeve is put on the inner ring of the gear, and the middle conical sleeve is put between the inner and outer conical sleeves. The set screws are tightened to compress the inner and outer conical sleeves, and the gear, the shaft head and the conical sleeve are closely fitted to achieve the connection effect.

[0037] When connecting, pay attention to the uniform application of force and the tightening force of the set screws should be moderate. Too much or too little force will affect the connection effect.

[0038] If you want to adjust the gap between the rotor and the end face of the pump body, just use the disassembly screws to lift the bearing seat, then pad a thin copper sheet of appropriate thickness on the joint surface between the bearing seat and the end cover, and then fix the bearing seat. This makes disassembly and adjustment of the gap very convenient and simple.

[0039] If you need to adjust the meshing clearance between the rotors, just loosen the set screws of the driven gear cone sleeve, adjust the meshing clearance between the rotors, and then tighten the set screws on the cone sleeve in turn, so that you can easily repair the Roots vacuum pump.

[0040] The above are only specific application examples of the utility model, and do not constitute any limitation on the protection scope of the utility model. Any technical solution formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the utility model.

Claims

1. A Roots vacuum pump with a high-reliability gear transmission, comprising a pump body (1), wherein the front end of the pump body (1) is provided with a front cover (4), and the rear end is provided with a rear cover (2), the front end cover (4) is provided with a front cover (5), and the rear end cover (2) is provided with a rear cover (3); a pair of three-leaf involute rotors (9) which are parallel, horizontally installed and meshed with each other are provided in the pump body (1): a driving rotor and a driven rotor, the driving rotor is arranged on a main shaft, and the driven rotor is arranged on a rotor shaft (10), the main shaft and the rotor shaft (10) are arranged in the pump body (1), characterized in that: The rear cover (3) is provided with a synchronous gear (6), and the synchronous gear (6) is sleeved on the end of the main shaft; the driving rotor and the driven rotor are connected to the pump body (1) through a pair of synchronous gears (6) in the oil tank so that the rotor (9) rotates synchronously and at a constant speed; the driving rotor and the driven rotor are respectively installed in the front cover (4) and the rear cover (2) at both ends of the pump body through bearings (8); A set of double-conical expansion rings (7) is provided between the synchronous gear (6) and the rotor shaft (10), the double-conical expansion ring (7) comprising an inner conical sleeve (7.1), an intermediate conical sleeve (7.2) and an outer conical sleeve (7.3) which are sequentially sleeved from the inside to the outside, the outer sleeve of the rotor shaft (10) is sleeved with the inner conical sleeve (7.1), the outer conical sleeve (7.3) is sleeved on the inner ring of the synchronous gear (6), an intermediate conical sleeve (7.2) is provided between the inner conical sleeve (7.1) and the outer conical sleeve (7.3), and the intermediate conical sleeve (7.2) is fastened by inserting a set screw (7.4).

2. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: The outer wall of the inner cone sleeve (7.1) is provided with two symmetrical outer cone surfaces, and the inner wall of the outer cone sleeve (7.3) is provided with two symmetrical inner cone surfaces. The inner cone sleeve (7.1) and the outer cone sleeve (7.3) are symmetrically arranged with respect to the middle cone sleeve (7.2).

3. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: The intermediate cone sleeve (7.2) is in the shape of an annulus, its outer ring is provided with an outer ring matching the outer cone sleeve (7.3), its inner ring is provided with an inner cone surface matching the inner cone sleeve (7.1), and no less than two set screws (7.4) are provided inside the annular ring of the intermediate cone sleeve (7.2) for fastening the connection.

4. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: The taper of the inner cone sleeve (7.1), the middle cone sleeve (7.2) and the outer cone sleeve (7.3) is 1:20, and the tapers of the inner cone sleeve (7.1), the middle cone sleeve (7.2) and the outer cone sleeve (7.3) are consistent.

5. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: The shaft end of the main shaft extends out of the front cover (5) and is connected to a coupling (11), and the coupling (11) is connected to a motor (12).

6. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: A piston ring labyrinth seal is provided at the connection between the rear end of the main shaft and the rear end cover (2).

7. A Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: A mechanical seal is provided at the connection between the front end of the main shaft and the front end cover (4).

8. The Roots vacuum pump with high reliability gear transmission according to claim 1, characterized in that: The pump body (1) is provided with an air inlet (1.1) at the upper end and an air outlet (1.2) at the lower end.

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