A claw pump rotor tooling and claw pump rotor assembly process

Abstract

The present invention belongs to the technical field of compressor assembly, and discloses a claw pump rotor tooling and claw pump rotor assembly process, including a radial limit block and an axial limit block fixedly connected, a stud is provided at the bottom of the axial limit block, a fastening nut is screwed on the stud, two limit block positioning pin holes corresponding to the two rotor positioning pin holes on the rotor are provided on the radial limit block, and two screw clearance holes corresponding to the two rotor threaded holes on the rotor are also provided on the radial limit block, and the positioning pins are inserted into the limit block positioning pin holes and the rotor positioning pin holes for positioning, and the first fastening bolts are screwed into the screw clearance holes and the rotor threaded holes for fixing. The present invention also discloses a claw pump rotor assembly process. The present invention can simultaneously control the assembly accuracy of the meshing angle, inter-tooth clearance, tooth top clearance and end face clearance between the rotors, greatly simplifying the claw pump assembly process.

Description

Technical Field

[0001] The invention belongs to the technical field of compressor assembly, and in particular relates to a claw pump rotor tooling and a claw pump rotor assembly process. Background Art

[0002] The claw pump is a positive displacement rotary compressor, a gas boosting and conveying machine, and its main components include: rotor, cylinder, gearbox, synchronous gear, bearing seal, etc. When the claw pump is working, a pair of meshing rotors are driven by a pair of synchronous gears on the outside of the cylinder to rotate in opposite directions, and the meshing of the two rotors isolates the air intake and exhaust ports from each other. During the rotation process, the gas in the cylinder volume is pushed from the air intake to the exhaust port, which has a certain internal compression process, thereby achieving the purpose of gas boosting and conveying.

[0003] The working volume inside the claw pump cylinder is not completely isolated in actual situations. The gas will leak from the exhaust side to the suction side through some tiny gaps, which will cause the volumetric efficiency of the claw pump to decrease, power consumption to increase, and exhaust temperature to rise. Therefore, leakage through the gap should be avoided as much as possible. The surface perpendicular to the axis direction on the rotor and cylinder is called the end face, and the position with the maximum radius of the rotor is called the rotor tooth top when viewed from the end face direction. The leakage gap when the claw pump is working is mainly divided into: 1. The end face gap formed by the rotor end face and the cylinder end face; 2. The tooth top gap formed by the rotor tooth top and the cylinder wall; 3. The tooth gap between the rotor and the rotor. Therefore, in the process of assembling the claw pump rotor to the shaft, the rotor needs to be assembled to the correct axial position to ensure the end face gap of the claw pump; the correct meshing position needs to be ensured between the two rotors during the assembly process to ensure that the meshing relationship between the yin and yang rotors is normal and the gap between the rotor teeth is ideal; in the assembly process of the cylinder, the cylinder parts need to be accurately positioned to ensure the ideal tooth top gap between the rotor and the cylinder.

[0004] The existing rotor assembly technology has the following disadvantages:

[0005] 1) The existing inter-tooth clearance and tooth top clearance control technology is not adapted to the shrink fit assembly method, which will cause the inter-tooth clearance of the heated rotor to become larger during assembly after cooling, resulting in an increase in the leakage of the claw pump and affecting the working performance of the claw pump;

[0006] 2) The prior art generally requires a separate positioning link to achieve the correct meshing angle between the two rotors, which increases the complexity of the assembly process;

[0007] 3) Although the existing axial end face clearance adjustment device can reduce the axial positioning accuracy requirements when assembling the rotor, the clearance adjustment device requires additional parts, which increases the production and assembly costs and is more complicated in structure;

[0008] 4) The prior art cannot achieve simultaneous control of the tooth tip clearance, inter-tooth clearance, end face clearance and meshing position during rotor assembly through simple steps. Using separate steps to control the assembly accuracy of each clearance will greatly increase the complexity of the assembly process and the structural complexity of the claw pump body and tooling;

[0009] 5) The more common method in the existing shrink-fit rotor assembly technology is to insert a suitable feeler gauge at the end face gap, and the thickness of the feeler gauge is the required end face gap size. The problems of this method in practice include: the feeler gauge is difficult to pull out when the press-fit is too tight, the gap size cannot be guaranteed when the press-fit is too loose, and the end face gap size changes after the rotor cools down. In general, the assembly accuracy of this method is greatly affected by the proficiency of the operator, and the assembly result is not easy to guarantee;

[0010] Another common method in the existing shrink-fit rotor assembly technology is to add a rotor axial limit structure, and the structure is generally not heated. In this solution, the limit structure is not heated, which will cause the end face clearance value during shrink-fit to be different from the end face clearance value after cooling, usually resulting in an increase in the end face clearance. Summary of the invention

[0011] In order to solve the problems existing in the above-mentioned background technology, the present invention proposes a claw pump rotor tooling and a claw pump rotor assembly process, which can realize the simultaneous control of the key gaps in the claw pump compression chamber - end face clearance, tooth top clearance, inter-tooth clearance and meshing angle during the rotor assembly process, thereby reducing the difficulty of claw pump rotor assembly, improving the assembly accuracy of claw pump rotor, and ensuring the safe and reliable operation of the claw pump.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0013] A claw type pump rotor tooling comprises a radial limit block and an axial limit block, wherein the radial limit block and the axial limit block are fixedly connected by a second fastening bolt, a stud is arranged at the bottom of the axial limit block, a fastening nut is screwed on the stud, and at least two studs are arranged; two limit block positioning pin holes corresponding to two rotor positioning pin holes on the rotor are opened on the radial limit block, and two screw clearance holes corresponding to two rotor threaded holes on the rotor are also opened on the radial limit block, the positioning pin is inserted into the limit block positioning pin hole and the rotor positioning pin hole for positioning, and the first fastening bolt is screwed into the screw clearance hole and the rotor threaded hole for fixing.

[0014] In this way, the stud and the fastening nut cooperate to guide and fasten the claw pump casing when installing it. The positioning pin holes are used to fix the angles of the two rotors during assembly and determine the gap between the teeth of the two rotors. At the same time, the two pairs of positioning pin holes can also be used to determine the relative positions of the two rotors in the radial direction at the beginning of assembly, that is, the cold and hot center distances of the two rotors, and then determine the claw pump tooth top gap.

[0015] Wherein, there are 4 studs.

[0016] Wherein, the material of the axial limit block is the same as that of the rotor.

[0017] The axial length of the axial positioning block is the sum of the axial length of the rotor and the end face clearance, which can be used to ensure the assembly accuracy of the end face clearance before and after the shrink fit.

[0018] The present invention also discloses a claw pump rotor assembly process, comprising the following steps:

[0019] S1: Use the second fastening bolt to fasten the radial limit block and the axial limit block, use two pairs of positioning pins to position a pair of rotors on the radial limit block, and then use the first fastening bolt to fasten the rotor and the radial limit block;

[0020] S2: Heat the connected claw pump rotor fixture and claw pump rotor to the design temperature at the same time. At this time, the diameter of the rotor shaft hole is larger than the diameter of the shaft. The heating temperature varies according to the rotor material.

[0021] S3: Install the bolt holes of the claw pump body along the studs, align the rotating shaft with the shaft hole of the rotor and insert it, push it until the end surface of the compression chamber is close to the limit surface on the axial limit block, and tighten the fixing nut;

[0022] S4: After cooling to room temperature, remove the fastening nut, the first fastening bolt, and the claw pump rotor tooling, and the rotor assembly process is completed.

[0023] Wherein, an elastic washer is arranged between the first fastening bolt and the radial limit block, and the elastic washer should be used when the bolt is tightened to prevent the stress and strain changes during the heating and cooling process from having an adverse effect on the assembly accuracy.

[0024] Among them, an elastic washer is arranged between the fastening nut and the claw pump body, and the elastic washer should be used under the fastening nut to prevent the stress and strain changes during the heating and cooling process from having an adverse effect on the assembly accuracy.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention can simultaneously control the assembly accuracy of the meshing angle, inter-tooth clearance, tooth tip clearance and end face clearance between the rotors, greatly simplifying the claw pump assembly process;

[0027] 2. The present invention can assemble two rotors at the same time, and realizes simultaneous control of the meshing angle, inter-tooth clearance and tooth tip clearance by specially designing the position of the positioning pin hole on the rotor tooling. The scheme has a simple structure and a clever design, avoiding the shortcomings of the prior art of separately controlling different clearances and the need to design a special complex structure for the technical scheme;

[0028] 3. The control of the inter-tooth clearance, tooth top clearance and end face clearance in the present invention is optimized for the shrink-fit assembly method, which changes the previous method that the upper limit device of the tooling does not change with the temperature, so that the inter-tooth clearance, tooth top clearance and end face clearance values ​​change with the temperature during the heating-cooling process, and the clearance value returns to the design value after cooling after assembly;

[0029] 4. The control of the gap in the present invention is optimized for the shrink-fit assembly method, and the method of tightening bolts and nuts is used to provide a clamping force that can change with temperature, thereby avoiding the disadvantages of the common pressure equipment that the pressure is immutable and the pressure may be reduced due to thermal deformation of the parts, and also eliminating the steps of providing and using special pressure equipment;

[0030] 5. The tooling structure proposed by the present invention is simple, small in size, low in cost, simple in assembly process, easy to operate, and does not require operator experience to ensure assembly accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic structural diagram of a claw pump rotor tooling.

[0032] Figure 2 The figure is a schematic diagram of the assembly process of a claw pump rotor assembly process of the present invention.

[0033] Figure 3 The present invention is a schematic cross-sectional view of the assembly process of a claw pump rotor assembly process. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] See also Figure 1-Figure 3As shown, the present invention provides the following technical solutions: a claw pump rotor tooling, comprising a radial limit block 1 and an axial limit block 2, the radial limit block 1 and the axial limit block 2 are fixedly connected by a second fastening bolt 10, a stud 3 is arranged at the bottom of the axial limit block, a fastening nut 11 is screwed on the stud, and at least two studs are arranged; two limit block positioning pin holes 17 corresponding to the two rotor positioning pin holes on the rotor are opened on the radial limit block, and two screw clearance holes 18 corresponding to the two rotor threaded holes on the rotor are also opened on the radial limit block, and the positioning pin 8 is inserted into the limit block positioning pin hole and the rotor positioning pin hole for positioning, and the first fastening bolt 9 is screwed into the screw clearance hole and the rotor threaded hole for fixing; the stud 3 can also be used as an independent part without being connected to the axial limit block 2. At this time, the stud 3 and the matching nut are only used to press the casing 6 and the axial limit block 2.

[0036] In this way, the stud and the fastening nut cooperate to guide and fasten the claw pump casing when installing it. The positioning pin holes are used to fix the angles of the two rotors during assembly and determine the gap between the teeth of the two rotors. At the same time, the two pairs of positioning pin holes can also be used to determine the relative positions of the two rotors in the radial direction at the beginning of assembly, that is, the cold and hot center distances of the two rotors, and then determine the claw pump tooth top gap.

[0037] Wherein, there are 4 studs.

[0038] Wherein, the material of the axial limit block is the same as that of the rotor.

[0039] The axial length of the axial positioning block is the sum of the axial length of the rotor 4 and the end face clearance, which can be used to ensure the assembly accuracy of the end face clearance before and after the shrink fit.

[0040] During assembly, if the axial length of the assembled rotor 4 changes while the axial stop block 2 remains fixed, the size of the end face clearance between the rotor end face 13 and the compression chamber end face 15 will change. When the end face clearance is larger than the design value, a feeler gauge of appropriate size can be added between the end face 14 of the radial stop block 1 and the end face 5 of the rotor 4 and tightened with bolts; when the end face clearance is smaller than the design value, a feeler gauge of appropriate size can be added between the axial stop block end face 16 of the axial stop block 2 and the compression chamber end face 15 and tightened with bolts. This solution can ensure that the size of the end face clearance is always the difference between the axial length of the axial stop block 2 and the axial length of the rotor 4, which ensures that the size of the end face clearance will basically not change during the heating-cooling process.

[0041] The positions of each pair of limit block locating pin holes 17 and bolt clearance holes 18 on the claw pump manual shrink fit rotor tooling are the same as the opening positions on the corresponding rotor 4 in the cold state. Therefore, the pair of limit block locating pin holes 17 corresponding to a single rotor on the radial limit block 1 can fix the angle of the rotor 4 during the assembly process, and the two pairs of limit block locating pin holes 17 can fix the correct meshing relationship of a pair of rotors 4 during the assembly process. The two pairs of limit block locating pin holes 17 can also determine the relative radial position of the two rotors at the beginning of assembly, that is, the cold center distance of the two rotors. When the claw pump rotor is assembled, the two rotors are fixed on the radial limit block 1 and heated at the same time in order to ensure the correct meshing angle relationship between the two rotors. This will cause the center distance between the two rotors to increase due to the expansion of the radial limit block 1 after heating. The distance between the centers of the two rotors after heating is called the hot center distance. The hot center distance is the design value of the claw pump rotor center distance. Assuming that the thermal expansion of the radial stop block 1 at each position during the heating process is uniform, and the rotor and the radial stop block are made of the same material, the cold center distance of the two rotors can be calculated from the thermal expansion coefficient of the material, the designed heating temperature and the hot center distance. The calculated cold center distance is used to determine the center position of the two rotors on the radial stop block 1, and then the position of the required stop block locating pin hole 17 on the radial stop block 1 can be determined according to the relative position of the rotor locating pin hole on each rotor and the center of each rotor. The arrangement method of the stop block locating pin hole 17 ensures the relative position between the rotors during manual shrink fitting, thereby determining the inter-tooth clearance between the rotors; at the same time, when the center distance of the two rotors is determined, the tooth top clearance between the rotor and the cylinder is also determined. Therefore, the arrangement method of the stop block locating pin hole 17 can achieve simultaneous control of the claw pump tooth clearance, tooth top clearance and rotor meshing angle.

[0042] The present invention also discloses a claw pump rotor assembly process, comprising the following steps:

[0043] S1: Use the second fastening bolts 10 to fasten the radial limit block 1 and the axial limit block 2, use two pairs of positioning pins 8 to position a pair of rotors 4 on the radial limit block 1, and then use the first fastening bolts 9 to fasten the rotor 4 and the radial limit block 1;

[0044] S2: heating the connected claw pump rotor fixture and claw pump rotor to the design temperature at the same time, at which time the diameter of the rotor shaft hole is larger than the diameter of the rotating shaft 7, and the heating temperature varies according to the rotor material;

[0045] S3: Install the bolt hole 12 of the claw pump body 6 along the stud 3, align the rotating shaft with the shaft hole of the rotor and insert it, push it until the end surface of the compression chamber is close to the limit surface on the axial limit block, and tighten the fastening nut;

[0046] S4: After cooling to room temperature, remove the fastening nut 11, the first fastening bolt 9, and remove the claw pump rotor tooling, and the rotor assembly process is completed.

[0047] Wherein, an elastic washer is arranged between the first fastening bolt and the radial limit block, and the elastic washer should be used when the bolt is tightened to prevent the stress and strain changes during the heating and cooling process from having an adverse effect on the assembly accuracy.

[0048] Among them, an elastic washer is arranged between the fastening nut and the claw pump body, and the elastic washer should be used under the fastening nut to prevent the stress and strain changes during the heating and cooling process from having an adverse effect on the assembly accuracy.

[0049] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A claw pump rotor fixture, characterized in that: It comprises a radial limit block and an axial limit block, the radial limit block and the axial limit block are fixedly connected by a second fastening bolt, a stud is arranged at the bottom of the axial limit block, a fastening nut is screwed on the stud, and at least two studs are arranged; two limit block positioning pin holes corresponding to two rotor positioning pin holes on the rotor are opened on the radial limit block, and two screw clearance holes corresponding to two rotor threaded holes on the rotor are also opened on the radial limit block, and the positioning pin is inserted into the limit block positioning pin hole and the rotor positioning pin hole for positioning, and the first fastening bolt is screwed into the screw clearance hole and the rotor threaded hole for fixing; The axial length of the axial limit block is the sum of the axial length of the rotor and the end surface clearance; An elastic washer is provided between the first fastening bolt and the radial limiting block; An elastic washer is arranged between the fastening nut and the claw pump body.

2. A claw pump rotor fixture according to claim 1, characterized in that: There are four studs provided.

3. A claw pump rotor fixture according to claim 1, characterized in that: The material of the axial limit block is the same as that of the rotor.

4. A claw pump rotor assembly process, characterized in that: The claw pump rotor fixture according to any one of claims 1 to 3 is used, comprising the following steps: S1: Use the second fastening bolt to fasten the radial limit block and the axial limit block, use two pairs of positioning pins to position a pair of rotors on the radial limit block, and then use the first fastening bolt to fasten the rotor and the radial limit block; S2: Heat the connected claw pump rotor fixture and claw pump rotor to the design temperature at the same time, at which time the rotor shaft hole diameter is larger than the shaft diameter; S3: Install the bolt holes of the claw pump body along the studs, align the rotating shaft with the shaft hole of the rotor and insert it, push it until the end surface of the compression chamber is close to the limit surface on the axial limit block, and tighten the fixing nut; S4: After cooling to room temperature, remove the fastening nut, the first fastening bolt, and the claw pump rotor tooling, and the rotor assembly process is completed.

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