A processing tooling and processing method for the rotor component of a Roots flowmeter

Abstract

The present invention relates to a machining tool and a machining method for a Roots flowmeter rotor component, which solves the problem that the existing machining method for the rotor component cannot ensure machining accuracy. The tool comprises two groups of pressing pieces, which are respectively used to fix two sides of a rotor profile of a rotor in the machining rotor component. The pressing pieces comprise a pressing block, a pressing plate, two core shafts for fixing the rotor profile, and a fixing bolt installed on the pressing block and used to connect the pressing block to an external workbench. The pressing block is installed on the upper side of the pressing plate. One end of the two core shafts is connected to the pressing plate, and the other end is used to fix the rotor profile, and the axes of the two core shafts are parallel to each other. The center distance between the two core shafts is equal to the center distance between two through holes on the rotor profile. The present invention also proposes a Roots flowmeter rotor component machining method using the above tool.

Description

Technical Field

[0001] The invention relates to a machining tool and a machining method for a Roots flowmeter rotor component. Background Art

[0002] The HLQZ gas Roots flowmeter is primarily composed of a housing, conjugate rotors, and a flow totalizer. A pair of conjugate rotors housed within the metering chamber maintain correct relative positions under the influence of the inlet and outlet pressure differential (Pin > Pout) of the circulating gas. Precision-machined synchronous gears maintain optimal working clearances between the rotors, between the rotor and the housing, and between the rotor and the wall, achieving continuous, contactless sealing.

[0003] Since it is necessary to maintain continuous contactless sealing during the relative motion between the rotors, the size and form and position tolerances of the rotor components are required to be high. During the entire processing, especially the processing of the four involute curved surfaces of the rotor, since they are irregular surfaces, while ensuring the size, the straightness, runout and symmetry of the processed surfaces must also be met. Only in this way can the optimal working gap be maintained during actual operation and continuous contactless sealing be achieved.

[0004] Existing rotor component machining typically uses the rotor shafts at both ends as positioning references, with three-jaw clamping and center positioning on the workbench. This only limits four degrees of freedom, leaving no restrictions on X-axis rotation or Y-axis movement. During machining, the cutting force causes displacement and deformation in two degrees of freedom, directly leading to deviations in straightness and symmetry, making it impossible to guarantee machining accuracy. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing machining method of rotor components cannot ensure machining accuracy, and to provide a machining tool and a machining method for the rotor components of a Roots flowmeter.

[0006] The technical solutions of the present invention are as follows:

[0007] A machining tool for the rotor components of a Roots flowmeter, which is special in that:

[0008] The method comprises two sets of pressing pieces, wherein the two sets of pressing pieces are respectively used for fixing two sides of a rotor profile of a rotor in a rotor component;

[0009] The pressing piece includes a pressing block, a pressing plate, two core shafts for fixing the rotor profile, and fastening bolts installed on the pressing block for connecting the pressing block and the external workbench;

[0010] The pressing block is installed on the upper side of the pressing plate;

[0011] One end of the two core shafts is connected to the pressure plate, and the other end is used to fix the rotor profile, and the axes of the two core shafts are parallel to each other;

[0012] The center distance between the two core shafts is equal to the center distance between the two through holes on the rotor profile.

[0013] Furthermore, one end of the two core shafts is vertically connected to the pressing plate.

[0014] The present invention also provides a method for processing a Roots flowmeter rotor component, which is special in that it is based on the processing tooling of the Roots flowmeter rotor component, and includes the following steps:

[0015] Step 1: Processing and assembly of the rotor shaft

[0016] 1.1 Process the outer circles of the lower ends of the two rotor shafts respectively;

[0017] 1.2 Machine the center holes in the middle of the upper ends of the two rotor shafts respectively;

[0018] 1.3 After heating the rotor profile, press the two rotor shafts into the two blind holes at both ends of the rotor profile to complete the assembly of the two rotor shafts and the rotor profile;

[0019] 1.4 Process the outer circle and end surface of the upper ends of the two rotor shafts to complete the machining of the rotor shafts;

[0020] Step 2: Processing of the involute surface of the rotor profile

[0021] 2.1 Use the set bolts to fix the pressing block on the workbench, and adjust the set bolts to pre-tighten the rotor profile on the workbench through the core shaft. After aligning the rotor shafts at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile and process the positioning reference surface on the upper side mentioned above;

[0022] 2.2 Remove the two pressing parts and turn the rotor profile 180°;

[0023] 2.3 Pre-tighten the rotor profile on the workbench again through the mandrel, align the rotor shafts at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile again, and process the rotor involute surface on the upper side to the specified size;

[0024] 2.4 Remove the two pressing parts and turn the rotor profile 180° again. Pre-tighten the rotor profile on the workbench again through the core shaft. After aligning the rotor shafts at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile again. Process the rotor involute surface to the specified size on the upper side mentioned above to complete the processing of the two involute surfaces of the rotor profile.

[0025] Furthermore, in step 1.3, the rotor shaft and the blind hole are interference fit.

[0026] Furthermore, the step 1.4 is specifically as follows:

[0027] Based on the center points of the two center holes in step 1.2, the outer circles and end faces of the upper ends of the two corresponding rotor shafts are machined respectively to obtain the machined rotor shafts, thereby completing the machining of the rotor shafts.

[0028] Furthermore, in step 2.1, the positioning reference plane is a plane.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. Compared with the existing machining method of rotor parts, the present invention can ensure the straightness, runout and symmetry of the four involute surfaces of the rotor parts.

[0031] When machining the involute surface of a rotor component on a machining center of a machine tool, the rotor component to be machined needs to withstand the axial and radial cutting forces of the tool on the surface of the rotor component to be machined. In the present invention, by performing a primary reference positioning on the rotor component, performing a secondary alignment on the machining surface of the rotor component by dialing, and fixing the rotor component to the workbench by two sets of pressing pieces, the six degrees of freedom of the rotor component are limited, effectively ensuring that the straightness and runout of the rotor component will not be out of tolerance due to displacement or deformation during the machining process;

[0032] After processing one side, flip it to the other side. While keeping the reference plane unchanged, align the machining surface of the rotor component again and then fix it for processing to ensure the symmetry of the two involute surfaces.

[0033] 2. In the present invention, the rotor component is restricted in 6 degrees of freedom, which avoids the displacement and deformation of the rotor component caused by the cutting force of the machine tool, ensures the requirements of the form and position tolerance after processing, and improves the straightness deviation of the existing processing method from 0.08 to 0.015, the symmetry deviation from 0.12 to 0.015, and the runout deviation from 0.06 to 0.015.

[0034] 3. The tooling proposed in the present invention uses a universal pressing plate, a pressing block, a core shaft and a set screw, and the clamping tool is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 1. It is a schematic diagram of the structure of the tooling and rotor components for processing the rotor components of a Roots flowmeter in an embodiment of the present invention;

[0036] Figure 2 is a cross-sectional view of a rotor component in an embodiment of the present invention;

[0037] Figure 3 1 is a left side view of a rotor component in an embodiment of the present invention;

[0038] In the figure, 1, rotor shaft; 2, rotor; 3, pressing piece; 31, pressing block; 32, pressing plate; 33, core shaft; 34, tightening bolt. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] The lower end proposed in the present invention is the end of the rotor shaft 1 inserted into the blind hole, and the upper end is the end away from the blind hole.

[0041] In the present invention, Figure 1-Figure 3 As shown, the relevant rotor components include a rotor 2 and two rotor shafts 1, and the lengths of the two rotor shafts 1 are not equal;

[0042] Coaxial blind holes are provided at both ends of the middle portion of the rotor 2. Through holes are symmetrically provided on both sides of the rotor 2 along the axis of the blind hole. The rotor 2 has involute curved surfaces connected to each other on opposite sides parallel to the axis of the blind hole.

[0043] The lower ends of the two rotor shafts 1 are solid and are used for installation in conjunction with blind holes. A center hole is coaxially provided in the middle of the upper ends for machining and positioning of the rotor components and for ensuring coaxiality, circular runout and parallelism.

[0044] Among them, the rotor 2 is obtained by machining two involute surfaces on the rotor profile;

[0045] The outer circle of the lower end, the center hole, the outer circle and the end face of the rotor shaft 1 need to be processed.

[0046] In order to ensure the machining accuracy of the rotor components, the present invention proposes a tool for machining the rotor components of a Roots flowmeter, such as Figure 1 As shown, it includes two sets of pressing pieces 3;

[0047] The pressing piece 3 includes a pressing block 31, a pressing plate 32, a set screw 34 and two core shafts 33;

[0048] The pressure block 31 is connected to the external machine tool through a set screw 34 to fix the pressure piece 3. The pressure block 31 is installed on the upper side of the pressure plate 32 and is used to install two core shafts 33; the two core shafts 33 are connected in parallel to the lower side of the pressure plate 32, and the axes of the core shafts 33 are perpendicular to the pressure plate 32; the center distance of the two core shafts 33 is equal to the center distance of the two through holes on the rotor profile, and the two core shafts 33 are respectively inserted into the two through holes, and the core shafts 33 are in linear contact with the bottom end of the through hole to avoid applying external force in an extra direction to the rotor profile, thereby fixing the rotor profile through the two core shafts 33.

[0049] Based on the above-mentioned tooling for processing a Roots flowmeter rotor component, the present invention further proposes a processing method for a Roots flowmeter rotor component, comprising the following steps:

[0050] Step 1: Processing and assembly of rotor shaft 1

[0051] 1.1 Turn the outer circle of the lower end of the two rotor shafts 1 separately, and keep the outer circle size of the lower end of the two rotor shafts 1 at ф12 +0.044 +0.033 , so that there is an interference fit between the lower end of the rotor shaft 1 and the blind hole of the rotor profile;

[0052] 1.2 Machine the center holes in the middle of the upper ends of the two rotor shafts 1 respectively;

[0053] 1.3 After heating the rotor profile to 200℃±10℃ in an electric furnace, remove it from the furnace and use a hydraulic press to press the two rotor shafts 1 into the two blind holes of the rotor profile. The rotor shafts 1 and the blind holes of the rotor profile form an interference fit, completing the assembly of the rotor shafts 1.

[0054] 1.4 Process the outer circle and end surface of the upper ends of the two rotor shafts 1;

[0055] Based on the center points of the two center holes, the outer circles and end faces of the upper ends of the two rotor shafts 1 are machined to obtain the machined rotor shafts 1, completing the machining of the rotor shafts 1. The purpose of step 1.4 is to ensure the coaxiality of the two rotor shafts 1, the coaxiality and circular runout of the outer circles of the rotor profile with the two rotor shafts 1, the perpendicularity of the two end faces of the rotor profile with the two rotor shafts 1 at both ends, and the parallelism of the two end faces of the rotor profile;

[0056] Step 2: Machining of the involute surface

[0057] 2.1 Insert the core shafts 33 of the two pressing pieces 3 into the two ends of the through-hole of the rotor profile respectively, and then press the pressing block 31 downward with the set screw 34 to achieve simultaneous pressure on the two core shafts 33. The core shaft 33 is in linear contact with the bottom end of the through-hole of the rotor profile. Then, by fixing the pressing blocks 31 on both sides, pre-tighten the rotor profile on the workbench of the machine tool. After aligning the rotor shafts 1 at both ends and the outer cylindrical surface of one side of the rotor profile using a lever dial indicator, tighten the rotor profile and mill the positioning reference surface on the upper side. The positioning reference surface is a plane. First, it is used to position the rotor components. Second, it ensures that the involute surface of the rotor profile is machined with the rotor shafts 1 at both ends as the reference, ensuring the symmetry of the involute surface relative to the rotor shafts 1 at both ends.

[0058] It is necessary to ensure that the core shaft 33 in the pressing piece 3 is inserted into the through hole of the rotor profile, and the core shaft 33 in the pressing piece 3 is in linear contact with the bottom end of the through hole of the rotor profile;

[0059] In this step, it is necessary to ensure that force is applied to the core shaft 33 on both sides of the rotor profile at the same time;

[0060] 2.2 Remove the two pressing pieces 3 and turn the rotor profile 180° so that the positioning reference surface of the rotor profile contacts the workbench of the machine tool;

[0061] 2.3 Insert the mandrels 33 of the two pressing pieces 3 into the ends of the through-hole of the rotor profile, then press down the pressing blocks 31 on both sides so that both mandrels 33 are pressed simultaneously and the mandrels 33 are in line contact with the bottom end of the through-hole of the rotor profile. Then, by fixing the pressing blocks 31 on both sides, pre-tighten the rotor profile on the workbench of the machine tool. Then, use a lever dial indicator to align the rotor shafts 1 at both ends and the outer cylindrical surface of one side of the rotor profile. Then, tighten the rotor profile. Then, mill the rotor involute surface to the specified size on the upper side as described above.

[0062] 2.4 Remove the two pressing pieces 3 and turn the rotor profile 180° again. Then, insert the core shafts 33 of the two pressing pieces 3 into the two ends of the through hole of the rotor profile respectively. Then, press down the pressing blocks 31 on both sides so that the two core shafts 33 are pressurized at the same time. The core shafts 33 are in line contact with the bottom end of the through hole of the rotor profile. Then, by fixing the pressing blocks 31 on both sides, pre-tighten the rotor profile on the workbench of the machine tool. Then, use the lever dial indicator to align the rotor shafts 1 at both ends and the outer cylindrical surface of one side of the rotor profile. Then, tighten the rotor profile. Then, mill the rotor involute surface to the specified size on the upper side as mentioned above to complete the processing of the two involute surfaces of the rotor profile.

[0063] In the present invention, when processing the involute surfaces on both sides of the rotor profile, the six degrees of freedom of the rotor component are always restricted by the two pressing pieces 3, and the rotor shafts 1 at both ends are always aligned by marking, so as to finally achieve the precision requirement of the symmetry of the involute surfaces on both sides of the rotor profile relative to the centers of the rotor shafts 1 at both ends.

Claims

1. A method for machining a Roots flowmeter rotor component, based on a machining tool for a Roots flowmeter rotor component, comprising two sets of pressing pieces (3), the two sets of pressing pieces (3) being used to fix two sides of a rotor profile of a rotor in the machining rotor component; The pressing piece (3) includes a pressing block (31), a pressing plate (32), two core shafts for fixing the rotor profile, and a fastening bolt (34) mounted on the pressing block (31) and used to connect the pressing block (31) and an external workbench; The pressing block (31) is mounted on the upper side of the pressing plate (32); One end of the two core shafts is connected to the pressure plate (32), and the other end is used to fix the rotor profile, and the axes of the two core shafts are parallel to each other; The center distance between the two core shafts is equal to the center distance between the two through holes on the rotor profile; It is characterized in that it includes the following steps: Step 1: Processing and assembly of the rotor shaft (1) 1.1 Process the outer circles of the lower ends of the two rotor shafts (1) respectively; 1.2 Process the center holes in the middle of the upper ends of the two rotor shafts (1) respectively; 1.3 After heating the rotor profile, the two rotor shafts (1) are respectively pressed into the two blind holes at both ends of the rotor profile to complete the assembly of the two rotor shafts (1) and the rotor profile; 1.4 Processing the outer circle and end surface of the upper ends of the two rotor shafts (1) to complete the processing of the rotor shafts (1); Step 2: Processing of the involute surface of the rotor profile 2.1 Use the set bolts (34) to fix the pressing block (31) on the workbench, and adjust the set bolts (34). Pre-tighten the rotor profile on the workbench through the core shaft. After aligning the rotor shafts (1) at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile and process the positioning reference surface on the upper side. 2.2 Remove the two pressing pieces (3) and turn the rotor profile 180°; 2.3 Pre-tighten the rotor profile on the workbench again through the core shaft, align the rotor shafts (1) at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile again, and process the rotor involute surface on the upper side to the specified size; 2.4 Remove the two pressing pieces (3) and turn the rotor profile 180 degrees again. Pre-tighten the rotor profile on the workbench again through the core shaft. After aligning the rotor shafts (1) at both ends and the outer cylindrical surface of one side of the rotor profile, tighten the rotor profile again. Process the rotor involute surface on the upper side to the specified size to complete the processing of the two involute surfaces of the rotor profile.

2. The method for processing a Roots flowmeter rotor component according to claim 1, characterized in that: In step 1.3, the rotor shaft (1) and the blind hole are interference fit.

3. The method for processing a Roots flowmeter rotor component according to claim 1 or 2, characterized in that: The step 1.4 is specifically as follows: Based on the centers of the two center holes in step 1.2, the outer circles and end faces of the upper ends of the two corresponding rotor shafts (1) are processed respectively to obtain the processed rotor shafts (1), thereby completing the processing of the rotor shafts (1).

4. The method for processing a Roots flowmeter rotor component according to claim 3, characterized in that: In step 2.1, the positioning reference surface is a plane.

5. The method for processing a Roots flowmeter rotor component according to claim 1, characterized in that: One end of the two core shafts is vertically connected to the pressing plate (32).

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