Gear tensioning structure for screw vacuum pump

Abstract

This utility model relates to a gear tensioning structure for a screw vacuum pump, comprising a gear, a first clamping plate, and a second clamping plate. The gear has a central shaft hole for mounting on a main shaft. The gear has an annular groove on both its front and back sides. The first and second clamping plates are annular and have identical structures. The inner wall of the first clamping plate is an inclined conical surface. The first and second clamping plates are respectively positioned within the annular grooves at the front and rear of the gear. Multiple disassembly screw holes are provided on both the first and second clamping plates. The annular grooves of the gear have corresponding screw holes. The gear, the first clamping plate, and the second clamping plate are connected and fixed together using hexagonal set screws. This utility model achieves micro-deformation of the gear, significantly improves assembly pass rate, and reduces noise through a radially coordinated locking design with two clamping plates.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission technology, and in particular to a gear tensioning structure for a screw vacuum pump. Background Technology

[0002] A screw vacuum pump achieves vacuuming by transmitting torque from a pair of synchronizing gears within the gearbox to a pair of screw rotors within the pump chamber. Since screw vacuum pumps can rotate at speeds up to 3000 rpm, the synchronizing gears are one of their key components. Improper gear structure, out-of-tolerance gear precision, or improper gear installation can all cause abnormal gear noise, excessive vibration, and abnormal temperature rise during operation, affecting the normal use of the screw vacuum pump.

[0003] Screw vacuum pumps rely on synchronous gears to transmit torque (up to 3000 rpm). The existing technology using the Z2 expansion sleeve structure has the following drawbacks:

[0004] (1) The outward expansion force generated after the expansion sleeve is locked can easily cause the teeth on the side with the expansion sleeve to deform outward. The deformation of the gear teeth is generally around 0.05mm, while the accuracy of the normal gear after installation must be controlled within 0.02mm, exceeding the tolerance by 150%;

[0005] (2) Poor positioning accuracy, the gears are prone to displacement and slippage after assembly;

[0006] (3) Disassembly is difficult and maintenance is time-consuming;

[0007] (4) Noise and temperature rise issues: Deformed gears cause abnormal noise and tooth surface temperature rise;

[0008] (5) The assembly is difficult and the assembly qualification rate is low: The Z2 expansion sleeve structure used in the existing gear is unreasonable, resulting in a very low assembly qualification rate of the screw vacuum pump. The randomness of assembly failure is very high, which affects the production progress.

[0009] The existing gear mounting structure seriously affects the transmission accuracy of the screw vacuum pump gears after assembly, causing many abnormal phenomena such as high gear noise, high temperature rise, and rapid tooth surface wear. Therefore, this utility model proposes a gear tensioning structure for screw vacuum pumps to solve the above problems. Summary of the Invention

[0010] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a gear tensioning structure for screw vacuum pumps. By using double clamping discs to apply force in concert, it solves the problems of gear deformation, noise and slippage caused by traditional expansion sleeves.

[0011] The purpose of this utility model is achieved as follows:

[0012] A gear tensioning structure for a screw vacuum pump includes a gear, a first clamping plate, and a second clamping plate. The gear has a central shaft hole for fitting onto a main shaft. The gear has an annular groove on its front and back sides for assembling the first and second clamping plates.

[0013] The first clamping plate and the second clamping plate are annular in shape and have the same structure. The inner wall of the first clamping plate is an inclined conical surface. The first clamping plate and the second clamping plate are respectively disposed in the annular grooves in front of and behind the gear, and the shape of the annular grooves is adapted to the first clamping plate and the second clamping plate.

[0014] The first and second clamping plates are provided with a plurality of evenly distributed disassembly screw holes. The annular groove of the gear is provided with screw holes corresponding to the disassembly screw holes of the clamping plates. The screw holes of the gear and the disassembly screw holes are coaxially aligned. The gear, the first clamping plate, and the second clamping plate are connected and fixed together by passing through the disassembly screw holes of the clamping plates and the screw holes of the gear with internal hexagon set screws.

[0015] Furthermore, the inner holes of the first and second clamping discs are frustoconical, with the side with the smaller diameter being the outer side and the side with the larger diameter being the inner side.

[0016] Furthermore, the clearance between the shaft hole of the gear and the main shaft is ≤0.02mm.

[0017] Furthermore, the gear has 10°~15° conical surfaces on both sides.

[0018] Furthermore, the inclination angle of the inner hole of the first clamping plate or the second clamping plate is 6°, and the inner conical surface matches the gear cone angle.

[0019] Furthermore, the socket head cap screw is a 10.8 grade high-strength screw.

[0020] Compared with the prior art, the beneficial effects of this utility model are:

[0021] This invention provides a gear tensioning structure for a screw vacuum pump. Through a dual-clamping disc radial cooperative locking design, it achieves gear deformation of no more than 0.005mm, significantly improving assembly pass rate and reducing noise to below 75dB. It has the following advantages:

[0022] (1) Improved precision: Gear deformation was reduced to 0.005mm, a 90% improvement compared to the Z2 expansion sleeve;

[0023] (2) Enhanced reliability: Improved torque transmission with no slippage;

[0024] (3) Noise control: Operating noise ≤75dB;

[0025] (4) Easy to disassemble and assemble: greatly shortens maintenance time. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] Figure 2 This is the front view of the present invention.

[0028] Figure 3 This is a schematic diagram illustrating the application of this utility model.

[0029] in:

[0030] Gear 1, Shaft Hole 1.1, First Clamping Plate 2, Second Clamping Plate 3, Removal Screw Hole 4, Socket Head Set Screw 5, Main Shaft 6. Detailed Implementation

[0031] To better understand the technical solution of this utility model, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of this utility model, but are merely possible implementations of the technical solution of this utility model. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components. Example 1

[0032] See Figure 1-3 , Figure 1 A schematic diagram of the structure of this utility model has been drawn. As shown in the figure, this utility model relates to a gear tensioning structure for a screw vacuum pump, which includes a gear 1, a first clamping plate 2, and a second clamping plate 3. The gear 1 has a shaft hole 1.1 at its center, which is used to fit onto the main shaft 6. The front and back of the gear 1 are respectively provided with an annular groove for assembling the first clamping plate 2 and the second clamping plate 3.

[0033] The first clamping plate 2 and the second clamping plate 3 are annular, and the first clamping plate 2 and the second clamping plate 3 have the same structure. The inner wall of the first clamping plate 2 is an inclined conical surface, so the inner hole of the first clamping plate 2 and the second clamping plate 3 is frustoconical, with the side with the smaller diameter being the outer side and the side with the larger diameter being the inner side.

[0034] The first clamping plate 2 and the second clamping plate 3 are respectively disposed in the annular grooves in front of and behind the gear 1, and the shape of the annular grooves is adapted to the first clamping plate 2 and the second clamping plate 3.

[0035] The first clamping plate 2 and the second clamping plate 3 are provided with a plurality of evenly distributed disassembly screw holes 4. The annular groove of the gear 1 is provided with screw holes corresponding to the disassembly screw holes 4 of the clamping plate. The screw holes of the gear 1 and the disassembly screw holes 4 are coaxially aligned. The gear 1, the first clamping plate 2 and the second clamping plate 3 are connected and fixed together by passing through the disassembly screw holes 4 of the clamping plate and the screw holes of the gear 1 with internal hexagon set screws 5.

[0036] The gear 1 is made of 520CrMo material. The gap between the shaft hole 1.1 and the main shaft is 6≤0.02mm. The gear 1 has a 10°~15° conical surface on both sides, and the optimal angle of the conical surface is 12°.

[0037] The first clamping plate 2 and the second clamping plate 3 are made of 40Cr material. The inclination angle of the inner hole of the first clamping plate 2 or the second clamping plate 3 is 6°, and the inner conical surface matches the gear cone angle.

[0038] The internal hex socket set screw 5 is a 10.8 grade high-strength screw, tightened in stages with torque: 5Nm→10Nm→15Nm.

[0039] The surface of the internal hexagon set screw 5 is coated with molybdenum disulfide lubricant, and the preload deviation is ≤±3%.

[0040] The tooth profile error of the gear 1 is ≤0.005mm, and the roundness of the inner conical surface of the first clamping plate 2 and the second clamping plate 3 is ≤0.003mm.

[0041] This utility model relates to a gear tensioning structure for a screw vacuum pump, and its assembly process is as follows:

[0042] (1) Pretreatment:

[0043] Clean the gear holes, conical surfaces, and the inner conical surface of the clamping plate to ensure they are free of oil.

[0044] Insert the clamping disc into the gear annular groove and insert screws for pre-fixing (do not tighten).

[0045] (2) Spindle installation:

[0046] The assembly is fitted into the spindle, with the gear end face pressed against the spindle shoulder;

[0047] Tighten the screws in three stages, following a 180° diagonal sequence:

[0048] Stage 1: 5Nm preload, manually check gears for jamming;

[0049] Phase 2: Tighten to 10 Nm, and check the screw rotor clearance with a feeler gauge;

[0050] Phase 3: Final tightening at 15 Nm, gap passed re-inspection.

[0051] (3) Disassembly process:

[0052] Loosen the screws and screw the clamping disc into the removal screw hole;

[0053] Tighten the screws gradually until the clamping disc separates from the gear.

[0054] Working principle:

[0055] This utility model provides a gear tensioning structure for a screw vacuum pump. The clamping plate 1 and clamping plate 2 are placed at corresponding positions on both sides of the gear. A certain number of internal hexagon set screws are used to properly fix the gear, clamping plate 1, and clamping plate 2. The internal hexagon set screws only need to slightly fix the above three parts and do not need to be tightened too much.

[0056] Place the above assembly into one end of the screw vacuum pump spindle, and align one side of the gear with the end face of the spindle. Set the torque wrench to 5 Nm, and use the torque wrench to pre-tighten the six Allen head screws on the gear in a 180° diagonal pattern.

[0057] Since the main and driven gears of the screw vacuum pump have completely identical structures, the installation order of the main and driven gears and the main and driven shafts is not important.

[0058] After pre-tightening the driving and driven gears, rotate the gears by hand. During the rotation, the gears should loosen smoothly. Use a feeler gauge to measure the gaps at various points on the pair of screw rotors inside the pump chamber. Once the gaps are normal, set the torque wrench to 10 Nm and tighten the Allen head set screws on the driving and driven gears in sequence. Again, use a feeler gauge to measure the gaps at various points on the pair of screw rotors inside the pump chamber.

[0059] After verifying that the gaps at each point are normal, set the torque wrench to 15 Nm and then tighten the internal hex socket set screws on the driving and driven gears in sequence. This completes the gear assembly process.

[0060] Gear disassembly method: Loosen and remove the internal hex set screws on the gear one by one, and then screw them into the disassembly and assembly screw holes of clamping plate 1 one by one. Tighten the internal hex set screws one by one with an internal hex wrench until clamping plate 1 and clamping plate 2 are disengaged from the gear. The gear disassembly is thus completed.

[0061] After adopting the gear structure of this utility model, as long as the assembly process and control requirements are followed step by step, the final assembly qualification rate will be almost 100%, and the operating noise of the product will be much lower than the industry standard.

[0062] The gear inner hole and two side conical surfaces, as well as the inner conical hole and two planes of the clamping plate of this utility model, must be precision ground. The machining accuracy, including dimensional and geometric tolerances, must be well controlled. The preload must be well controlled during assembly, otherwise it will cause difficulties in disassembling the gear.

[0063] The advantages of using a tensioning disc conical surface connection for the gears in this utility model are: high positioning accuracy, conical surface meshing degree reaching 85% (i.e., contact area), small gear deformation, strong load-bearing capacity, gears are not easy to loosen or slip, convenient disassembly and assembly, good repeatability positioning accuracy, good reliability, and easier adjustment of the screw rotor clearance.

[0064] This invention relies on the strong radial clamping force generated by the clamping discs on both sides of the gear to lock the gear and the main shaft, thereby achieving a reliable connection between the gear and the main shaft and safe and quiet operation of the screw vacuum pump.

[0065] The above are merely specific application examples of this utility model and do not constitute any limitation on the scope of protection of this utility model. All technical solutions formed by equivalent transformations or equivalent substitutions fall within the scope of protection of this utility model.

Claims

1. A gear tensioning structure for a screw vacuum pump, characterized by: It includes a gear (1), a first clamping plate (2) and a second clamping plate (3). The gear (1) has a shaft hole (1.1) at its center, which is used to fit onto the main shaft (6). The gear (1) has an annular groove on its front and back sides for assembling the first clamping plate (2) and the second clamping plate (3). The first clamping plate (2) and the second clamping plate (3) are annular, and the first clamping plate (2) and the second clamping plate (3) have the same structure. The inner wall of the first clamping plate (2) is an inclined conical surface. The first clamping plate (2) and the second clamping plate (3) are respectively arranged in the annular grooves in front of and behind the gear (1). The shape of the annular grooves is adapted to the first clamping plate (2) and the second clamping plate (3). The first clamping plate (2) and the second clamping plate (3) are provided with a plurality of evenly distributed disassembly screw holes (4). The annular groove of the gear (1) is provided with screw holes corresponding to the disassembly screw holes (4) of the clamping plate. The screw holes of the gear (1) are coaxially aligned with the disassembly screw holes (4). The gear (1), the first clamping plate (2), and the second clamping plate (3) are connected and fixed together by passing through the disassembly screw holes (4) of the clamping plate and the screw holes of the gear (1) with internal hexagon set screws (5).

2. A gear tensioning structure for a screw vacuum pump according to claim 1, characterized in that: The inner holes of the first clamping plate (2) and the second clamping plate (3) are truncated cone-shaped, with the side with the smaller diameter being the outer side and the side with the larger diameter being the inner side.

3. The gear tensioner structure for a screw vacuum pump according to claim 1, characterized in that: The gap between the shaft hole (1.1) of the gear (1) and the main shaft (6) is ≤0.02mm.

4. The gear tensioner structure for a screw vacuum pump according to claim 1, characterized in that: The gear (1) has 10°~15° conical surfaces on both sides.

5. The gear tensioner structure for a screw vacuum pump according to claim 1, characterized in that: The inclination angle of the inner hole of the first clamping plate (2) or the second clamping plate (3) is 6°, and the inner conical surface matches the gear cone angle.

6. A gear tensioner structure for a screw vacuum pump according to claim 1, characterized in that: The internal hexagon set screw (5) is a 10.8 grade high-strength screw.

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