Auxiliary positioning device and method for processing impeller of Roots blower

Abstract

The invention belongs to the technical field of Roots blower impeller machining, and particularly relates to an auxiliary positioning device and method for Roots blower impeller machining. The base is detachably connected to a working platform of the numerical control machine tool, and end point coordinates of horizontal projection of the base on the working platform are known. The multiple supports are vertically and detachably connected to the two sides of the base in the width direction, and the multiple supports are symmetrical relative to the width center line of the base. A pair of linear telescopic devices is installed between every two adjacent supports located on the same side of the width direction of the base, and the pair of linear telescopic devices are oppositely arranged and are coaxial. The auxiliary positioning device for machining the Roots blower impeller has the advantages that the auxiliary positioning device for machining the Roots blower impeller can assist in positioning the axis endpoint coordinates of a plurality of inner holes of the Roots blower impeller while clamping and fixing the Roots blower impeller, and the center of each inner hole does not need to be positioned through a center drill, a special clamp and the like; and the efficiency of machining the inner hole of the Roots blower is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of Roots blower impeller machining, and in particular relates to a Roots blower impeller machining auxiliary positioning device and method. Background Art

[0002] The impeller of Roots blower is one of the key components, which is usually manufactured by casting process, especially sand casting process, which can produce impellers with complex shapes. After casting, the impeller of Roots blower needs to be processed on the outer surface and inner hole. The inner hole includes the center hole, weight reduction hole and balance hole.

[0003] When machining the inner hole of a Roots blower, it is necessary to determine the center of the inner hole. In the prior art, determining the center of the inner hole generally requires the following three steps: (1) Use a center drill for preliminary positioning: First, you can use a center drill to perform preliminary positioning of the hole center. The center drill has the characteristic of automatic centering, which can quickly find the center point of the material. During operation, you need to align the center drill with the expected drilling position, and then start the milling machine to drill. This step can help determine the approximate center position of the hole.

[0004] (2) Use fixtures to assist positioning: In order to improve positioning accuracy, special fixtures can be used to assist positioning. These fixtures usually have precise positioning functions and can ensure the stability of the workpiece during processing. After the workpiece is fixed on the fixture, the position of the workpiece can be accurately adjusted according to the marks on the fixture, thereby further ensuring the accuracy of the hole center.

[0005] (3) Use measuring tools for fine-tuning: After the initial positioning and fixture-assisted positioning, it is necessary to use precise measuring tools for fine-tuning. For example, tools such as micrometers or vernier calipers can be used to measure and adjust the position of the workpiece to ensure that the center of the hole is exactly the same as the expected position. This step is the key to ensuring machining accuracy.

[0006] Therefore, when using existing technology to process the center hole, weight reduction hole and balance hole of the Roots blower impeller, very complicated steps are required to determine the center of the inner hole, which is inefficient. Summary of the invention

[0007] Aiming at the technical problem of low efficiency in machining a center hole, a weight-reducing hole and a balancing hole of a Roots blower impeller in the prior art, the invention provides an auxiliary positioning device and method for machining a Roots blower impeller.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a Roots blower impeller processing auxiliary positioning device, comprising a base and a support; the base is detachably connected to the working platform of a CNC machine tool and the end point coordinates of the horizontal projection of the base on the working platform are known; a plurality of the supports are vertically detachably connected to both sides of the width direction of the base, and the plurality of the supports are symmetrical with respect to the width midline of the base; a pair of linear telescopic devices are installed between two adjacent supports on the same side of the width direction of the base, and the pair of linear telescopic devices are arranged oppositely and coaxially; The Roots blower impeller is placed on the upper surface of the base, and the axis of the Roots blower impeller is parallel to the width direction of the base; the end of the Roots blower impeller is between a pair of the linear telescopic devices, and the pair of linear telescopic devices clamp the end of the Roots blower impeller; the end of the linear telescopic device is tangent to the outer surface of the Roots blower impeller.

[0009] Preferably, the linear telescopic device is an electric telescopic rod, a pneumatic cylinder or a hydraulic cylinder; the linear telescopic device includes a mounting seat, a cylinder barrel, a piston rod and a splint, the piston rod is slidably connected to the cylinder barrel, the mounting seat is fixedly connected to the end of the cylinder barrel away from the piston rod; the splint is fixedly connected to the end of the piston rod; the mounting seat is detachably connected to the support.

[0010] Preferably, the linear telescopic device is provided with a displacement sensor.

[0011] Preferably, the base includes a plurality of branch bases, the plurality of branch bases include a front end base and a rear end base, the plurality of branch bases are arranged in parallel and have the same specifications; the spacing between the front end base and the rear end base can be adjusted according to the axial length of the Roots blower impeller.

[0012] Preferably, multiple groups of connection holes 1 are provided on the outer sides of the front end base and the rear end base, and connection holes 2 are provided on the support. The connection holes 1 and 2 are aligned and connected by bolts.

[0013] Preferably, the Roots blower impeller is a three-blade impeller; the Roots blower impeller processing auxiliary positioning device also includes a pressing mechanism, which includes a screw, a pressing nut and a pressure plate; the upper surfaces of the front end base and the rear end base are both provided with vertical threaded holes, and the threaded holes are located between the two three-blade impellers; the screw is threadedly connected to the threaded holes; a through hole is provided at the center of the pressure plate in the length direction, and the pressure plate is sleeved on the outer periphery of the screw through the through hole, and the two ends of the pressure plate respectively press the upper ends of the two three-blade impellers; the pressing nut is threadedly connected to the screw and presses the pressure plate from above.

[0014] A Roots blower impeller machining auxiliary positioning method, when the center hole and the weight-reducing hole of the three-blade impeller are milled and the balance hole is drilled, the Roots blower impeller machining auxiliary positioning device is used for auxiliary positioning, and the following steps are included: Step 1: Select a base and determine the installation position of the support according to the specifications of the three-blade impeller, and determine the endpoint coordinates of the horizontal projection of the base on the working platform; then detachably connect multiple supports to the base; Step 2: Place two cast three-blade impellers on the upper surface of the base, and clamp the end of each three-blade impeller by a pair of linear telescopic devices; after clamping, the end faces of the two three-blade impellers are flush, and the distance y1 from the end face of the three-blade impeller close to the tool to the base is obtained; after clamping, the lengths of the two linear telescopic devices on the same side of the three-blade impeller are the same, and the lengths of the pair of linear telescopic devices are x1 and x2 respectively; Step 3: Use the pressing mechanism to press and fix the upper ends of the two three-leaf impellers; Step 4: Use the known height h of the base, the thickness t of the support, the outer radius r of each blade of the three-blade impeller, and the above-mentioned y1, x1 and x2 to calculate the axis end point coordinates of the center hole, the weight reduction hole and the balance hole of the three-blade impeller respectively; Step 5: Input the axis endpoint coordinates of the center hole, lightening hole and balancing hole through the coordinate operation screen of the CNC machine tool, and then use the milling tool to perform milling and the drilling tool to perform drilling according to the input coordinates.

[0015] Preferably, in step one, the number of branch bases in the base is determined according to the axial length of the three-blade impeller, and the spacing between the front end base and the rear end base is adjusted to ensure that the lengths of the cantilevered part at the end and the middle suspended part of the three-blade impeller are less than 40 mm respectively; a group of connecting holes one connected to the support is determined according to the diameter of the three-blade impeller.

[0016] Preferably, the two weight-reducing holes at the lower part of the three-blade impeller are weight-reducing hole 1 and weight-reducing hole 2; The X-axis coordinate of the endpoint of the first axial line of the lightening hole is obtained by adding the endpoint coordinate of the horizontal projection of the base on the working platform to the support thickness t, x1, and the outer radius r of the blade; the Y-axis coordinate of the endpoint of the first axial line of the lightening hole is obtained by subtracting the length y1 of the end cantilever portion of the three-blade impeller from the endpoint coordinate of the horizontal projection of the base on the working platform; the Z-axis coordinate of the endpoint of the first axial line of the lightening hole is obtained by adding the height h of the base to the outer radius r of the blade; The Y coordinate of the endpoint of the axis of the second weight-reducing hole is the same as the Y coordinate of the endpoint of the axis of the first weight-reducing hole, and the Z coordinate of the endpoint of the axis of the second weight-reducing hole is the same as the Z coordinate of the endpoint of the axis of the first weight-reducing hole; the X coordinate of the endpoint of the axis of the second weight-reducing hole is obtained by adding the endpoint coordinate of the horizontal projection of the base on the working platform to the distance between two adjacent supports, then subtracting x2, and then subtracting the outer end radius r of the blade.

[0017] Preferably, the weight-reducing hole on the upper part of the three-blade impeller is weight-reducing hole three; the axial endpoints of weight-reducing hole three, the center hole and the balancing hole form a triangle with the axial endpoints of weight-reducing hole one and weight-reducing hole two, and the coordinates of the axial endpoints of weight-reducing hole three, the center hole and the balancing hole can be obtained through triangle geometry calculation.

[0018] Compared with the prior art, the advantages and positive effects of the present invention are: (1) The present invention changes the prior art. The auxiliary positioning device for machining a Roots blower impeller can assist in positioning the axis end point coordinates of multiple inner holes (including a center hole, a weight-reducing hole, and a balancing hole) of the Roots blower impeller while clamping and fixing the Roots blower impeller. It is no longer necessary to use a center drill, a special fixture, etc. to locate the center of each inner hole separately, thereby greatly improving the efficiency of machining the inner holes of the Roots blower. (2) The number of branch bases in the base is determined according to the axial length of the three-blade impeller, and the spacing between the front base and the rear base is adjusted to ensure that the lengths of the cantilevered portion at the end and the middle suspended portion of the three-blade impeller are less than 40 mm respectively; a group of connecting holes connected to the support is determined according to the diameter of the three-blade impeller; the above technical features enable the Roots blower impeller machining auxiliary positioning device of the present invention to meet the machining auxiliary positioning requirements of Roots blowers of different specifications, while ensuring the machining accuracy and surface quality of the Roots blower impeller; (3) The end of the Roots blower impeller is located between the pair of linear telescopic devices, and the pair of linear telescopic devices clamps the end of the Roots blower impeller therein; the end of the linear telescopic device is tangent to the outer surface of the Roots blower impeller; the above technical features are the key to achieving auxiliary positioning. To achieve the above technical solution, the axis of the linear telescopic device is collinear with the center of the first and second weight-reducing holes; (4) The auxiliary positioning device for Roots blower impeller processing can assist in positioning both two-blade impellers and three-blade impellers; (5) After clamping, the two linear telescopic devices on the same side of the three-blade impeller have the same length; ensure that the impeller axis of the Roots blower is parallel to the width direction of the base; (6) The coordinates of the axis endpoints of the center hole, the lightening hole and the balancing hole are input through the coordinate operation screen of the CNC machine tool, and then the milling tool is used to perform milling and the drilling tool is used to perform drilling according to the input coordinates; the processing of multiple inner holes can be completed without intermediate stoppage, and the efficiency is very high; (7) The X-coordinate of the endpoint of the axis of the second lightening hole is obtained by adding the endpoint coordinate of the horizontal projection of the base on the working platform to the distance between two adjacent supports, then subtracting x2, and then subtracting the outer radius r of the blade; the above technical solution converts the X-coordinate of the endpoint of the axis of the second lightening hole, which is difficult to obtain directly, into the algebraic sum of multiple values ​​that are convenient for accurate measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for describing the embodiment: Figure 1 The use state of the auxiliary positioning device for machining the impeller of the Roots blower in Example 1 Figure 1 ; Figure 2 The use state of the auxiliary positioning device for machining the impeller of the Roots blower in Example 1 Figure 2 ; Figure 3 The use state of the auxiliary positioning device for machining the impeller of the Roots blower in Example 1 Figure 3 ; Figure 4 This is a three-dimensional diagram of the linear telescopic device in the auxiliary positioning device for machining the impeller of a Roots blower; Figure 5 This is a usage status diagram of the Roots blower impeller processing auxiliary positioning device in Example 3.

[0020] Description of reference numerals: 1. base, 2. support; 3. linear telescopic device, 31. mounting seat, 32. cylinder, 33. piston rod, 34. clamping plate; 4. Screw, 5. Pressing nut, 6. Pressing plate, 7. Three-leaf impeller, 8. Two-leaf impeller, 9. Connecting hole 1, 10. Weight reduction hole, 11. Center hole. DETAILED DESCRIPTION

[0021] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0023] Example 1 Combine the following Figure 1-Figure 4 The Roots blower impeller machining auxiliary positioning device and method in Example 1 are further described as follows: Figure 1 As shown, the Roots blower impeller machining auxiliary positioning device in this embodiment includes a base 1 and a support 2; the base 1 is detachably connected to the working platform of the CNC machine tool and the endpoint coordinates of the horizontal projection of the base 1 on the working platform are known; a plurality of supports 2 are vertically detachably connected to both sides of the width direction of the base 1, and the plurality of supports 2 are symmetrical relative to the width midline of the base 1; a pair of linear telescopic devices 3 are installed between two adjacent supports 2 on the same side of the width direction of the base 1, and the pair of linear telescopic devices 3 are arranged oppositely and coaxially.

[0024] like Figure 1 and Figure 2 As shown, the Roots blower impeller is placed on the upper surface of the base 1, and the axis of the Roots blower impeller is parallel to the width direction of the base 1; the end of the Roots blower impeller is between a pair of linear telescopic devices 3, and the pair of linear telescopic devices 3 clamps the end of the Roots blower impeller therein; the end of the linear telescopic device 3 is tangent to the outer surface of the Roots blower impeller.

[0025] like Figure 4 As shown, the linear telescopic device 3 is a hydraulic cylinder; the linear telescopic device 3 includes a mounting seat 31, a cylinder barrel 32, a piston rod 33 and a clamping plate 34, the piston rod 33 is slidably connected to the cylinder barrel 32, the mounting seat 31 is fixedly connected to the end of the cylinder barrel 32 away from the piston rod 33; the clamping plate 34 is fixedly connected to the end of the piston rod 33; the mounting seat 31 is detachably connected to the support 2.

[0026] The linear telescopic device 3 is provided with a displacement sensor.

[0027] like Figure 3 As shown, the base 1 includes a plurality of branch bases, the plurality of branch bases include a front end base and a rear end base, the plurality of branch bases are arranged in parallel and have the same specifications; the spacing between the front end base and the rear end base can be adjusted according to the axial length of the Roots blower impeller.

[0028] like Figure 1 As shown, multiple groups of connection holes 1 9 are provided on the outer sides of the front end base and the rear end base, and connection holes 2 are provided on the support 2. The connection holes 1 9 and the connection holes 2 are aligned and connected by bolts.

[0029] like Figure 1 and Figure 2As shown, the impeller of the Roots blower is a three-blade impeller 7; the Roots blower impeller processing auxiliary positioning device also includes a pressing mechanism, which includes a screw 4, a pressing nut 5 and a pressing plate 6; vertical threaded holes are provided on the upper surfaces of the front end base and the rear end base, and the threaded holes are located between the two three-blade impellers 7; the screw 4 is threadedly connected to the threaded holes; a through hole is provided in the center of the pressing plate 6 in the length direction, and the pressing plate 6 is sleeved on the outer periphery of the screw 4 through the through hole, and the two ends of the pressing plate 6 respectively press the upper ends of the two three-blade impellers 7; the pressing nut 5 is threadedly connected to the screw 4 and presses the pressing plate 6 from above.

[0030] A Roots blower impeller machining auxiliary positioning method, when the center hole 11 and the weight reduction hole 10 of the three-blade impeller 7 are milled and the balance hole is drilled, the Roots blower impeller machining auxiliary positioning device is used to perform auxiliary positioning, including the following steps: Step 1: Select the base 1 and determine the installation position of the support 2 according to the specifications of the three-blade impeller 7, and determine the endpoint coordinates of the horizontal projection of the base 1 on the working platform; then detachably connect multiple supports 2 to the base 1; Step 2: Place two cast three-blade impellers 7 on the upper surface of the base 1, and clamp the end of each three-blade impeller 7 by a pair of linear telescopic devices 3; after clamping, the end faces of the two three-blade impellers 7 are flush, and the distance y1 from the end face of the three-blade impeller 7 close to the tool to the base 1 is obtained (which can be directly measured by a measuring ruler); after clamping, the lengths of the two linear telescopic devices 3 on the same side of the three-blade impeller 7 are the same, and the lengths of the pair of linear telescopic devices 3 are x1 and x2 respectively (which can be directly measured by a measuring ruler); Step 3: Use the pressing mechanism to press and fix the upper ends of the two three-blade impellers 7; Step 4: Using the known height h of the base 1, the thickness t of the support 2, the outer radius r of each blade of the three-blade impeller 7 (measured by an outside diameter micrometer), and the above-mentioned y1, x1, and x2, the axis end point coordinates of the center hole 11, the lightening hole 10, and the balancing hole of the three-blade impeller 7 are calculated respectively; Step 5: Input the axis endpoint coordinates of the center hole 11, the lightening hole 10 and the balancing hole through the coordinate operation screen of the CNC machine tool, and then use the milling tool to perform milling and the drilling tool to perform drilling according to the input coordinates.

[0031] In step one, the number of branch bases in the base 1 is determined according to the axial length of the three-blade impeller 7, and the spacing between the front end base and the rear end base is adjusted to ensure that the lengths of the end cantilever part and the middle cantilever part of the three-blade impeller 7 are less than 40 mm respectively; a group of connecting holes 9 connected to the support 2 is determined according to the diameter of the three-blade impeller 7.

[0032] The two weight-reducing holes 10 at the lower part of the three-blade impeller 7 are weight-reducing hole one and weight-reducing hole two; the axis of the linear telescopic device 3 is collinear with the centers of the weight-reducing hole one and the weight-reducing hole two (the Z-axis coordinate of the axis of the linear telescopic device 3 is obtained by adding the height h of the base 1 to the outer radius r of the blade); the X-axis coordinate of the end point of the axis of the weight-reducing hole one is obtained by adding the end point coordinate of the horizontal projection of the base 1 on the working platform to the thickness t of the support 2, x1, and the outer radius r of the blade; the Y-axis coordinate of the end point of the axis of the weight-reducing hole one is obtained by subtracting the length y1 of the end cantilever part of the three-blade impeller 7 from the end point coordinate of the horizontal projection of the base 1 on the working platform; the Z-axis coordinate of the end point of the axis of the weight-reducing hole one is obtained by adding the height h of the base 1 to the outer radius r of the blade.

[0033] The Y coordinate of the axis endpoint of the second weight-reducing hole is the same as that of the axis endpoint of the first weight-reducing hole, and the Z coordinate of the axis endpoint of the second weight-reducing hole is the same as that of the axis endpoint of the first weight-reducing hole; the X coordinate of the axis endpoint of the second weight-reducing hole is obtained by adding the endpoint coordinate of the horizontal projection of the base 1 on the working platform to the distance between two adjacent supports 2, then subtracting x2, and then subtracting the outer end radius r of the blade.

[0034] The weight-reducing hole 10 on the upper part of the three-blade impeller 7 is weight-reducing hole three; the axial end points of weight-reducing hole three, the center hole 11 and the balancing hole form a triangle with the axial end points of weight-reducing hole one and weight-reducing hole two. The coordinates of the axial end points of weight-reducing hole three, the center hole 11 and the balancing hole can be obtained through triangle geometry calculation.

[0035] The axial endpoint of the lightening hole 3 of the three-blade impeller 7 forms an equilateral triangle with the axial endpoints of the lightening hole 1 and the lightening hole 2; the axial endpoint of the center hole 11 is the center point of the above equilateral triangle.

[0036] Example 2 The difference between this embodiment and embodiment 1 is that the linear telescopic device 3 is a cylinder.

[0037] Example 3 The difference between this embodiment and embodiment 1 is: Figure 5 As shown, in this facility example, a Roots blower impeller machining auxiliary positioning device is used to position the end points of the inner hole axis of the two-leaf impeller 8.

[0038] The two weight-reducing holes 10 of the two-blade impeller 8 are weight-reducing hole one and weight-reducing hole two; the X-axis coordinate of the endpoint of the axis of the weight-reducing hole one is obtained by adding the endpoint coordinate of the horizontal projection of the base 1 on the working platform, the thickness t of the support 2, x1, and the outer radius r of the blade; the Y-axis coordinate of the endpoint of the axis of the weight-reducing hole one is obtained by subtracting the length y1 of the end cantilever part of the two-blade impeller 8 from the endpoint coordinate of the horizontal projection of the base 1 on the working platform; the Z-axis coordinate of the endpoint of the axis of the weight-reducing hole one is obtained by adding the height h of the base 1 and the outer radius r of the blade.

[0039] The Y coordinate of the axis endpoint of the second weight-reducing hole is the same as that of the axis endpoint of the first weight-reducing hole, and the Z coordinate of the axis endpoint of the second weight-reducing hole is the same as that of the axis endpoint of the first weight-reducing hole; the X coordinate of the axis endpoint of the second weight-reducing hole is obtained by adding the endpoint coordinate of the horizontal projection of the base 1 on the working platform to the distance between two adjacent supports 2, then subtracting x2, and then subtracting the outer end radius r of the blade.

[0040] The Y-axis coordinate of the axis endpoint of the center hole 11 of the two-blade impeller 8 is the same as the Y-axis coordinate of the axis endpoint of the weight-reducing hole 1, and the Z-axis coordinate of the axis endpoint of the center hole 11 is the same as the Z-axis coordinate of the axis endpoint of the weight-reducing hole 1. The X-axis coordinate of the axis endpoint of the center hole 11 is half of the sum of the X-axis coordinates of the weight-reducing hole 1 and the weight-reducing hole 2.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes for application in other fields. However, any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A Roots blower impeller machining auxiliary positioning device, characterized in that: The invention comprises a base (1) and a support (2); the base (1) is detachably connected to a working platform of a numerically controlled machine tool, and the end point coordinates of the horizontal projection of the base (1) on the working platform are known; a plurality of the supports (2) are vertically detachably connected to both sides of the base (1) in the width direction, and the plurality of the supports (2) are symmetrical with respect to the width midline of the base (1); a pair of linear telescopic devices (3) are installed between two adjacent supports (2) on the same side of the base (1) in the width direction, and the pair of linear telescopic devices (3) are arranged opposite to each other and are coaxial; The Roots blower impeller is placed on the upper surface of the base (1), and the axis of the Roots blower impeller is parallel to the width direction of the base (1); the end of the Roots blower impeller is located between a pair of linear telescopic devices (3), and the pair of linear telescopic devices (3) clamp the end of the Roots blower impeller therein; the end of the linear telescopic device (3) is tangent to the outer surface of the Roots blower impeller.

2. The Roots blower impeller machining auxiliary positioning device according to claim 1, characterized in that: The linear telescopic device (3) is an electric telescopic rod, a pneumatic cylinder or a hydraulic cylinder; the linear telescopic device (3) comprises a mounting seat (31), a cylinder barrel (32), a piston rod (33) and a clamping plate (34); the piston rod (33) is slidably connected to the cylinder barrel (32); the mounting seat (31) is fixedly connected to the end of the cylinder barrel (32) away from the piston rod (33); the clamping plate (34) is fixedly connected to the end of the piston rod (33); the mounting seat (31) is detachably connected to the support (2).

3. The Roots blower impeller machining auxiliary positioning device according to claim 2, characterized in that: The linear telescopic device (3) is provided with a displacement sensor.

4. The Roots blower impeller machining auxiliary positioning device according to claim 2 or 3, characterized in that: The base (1) comprises a plurality of branch bases, the plurality of branch bases comprising a front end base and a rear end base, the plurality of branch bases being arranged in parallel and having the same specifications; the spacing between the front end base and the rear end base can be adjusted according to the axial length of the Roots blower impeller.

5. The Roots blower impeller machining auxiliary positioning device according to claim 4, characterized in that: The front end base and the rear end base are provided with a plurality of groups of connection holes (9) on their outer sides, and the support (2) is provided with connection holes (2). The connection holes (9) and the connection holes (2) are aligned and connected by bolts.

6. The Roots blower impeller machining auxiliary positioning device according to claim 5, characterized in that: The Roots blower impeller is a three-blade impeller (7); the Roots blower impeller processing auxiliary positioning device also includes a pressing mechanism, which includes a screw (4), a pressing nut (5) and a pressure plate (6); the upper surfaces of the front end base and the rear end base are both provided with vertical threaded holes, and the threaded holes are located between the two three-blade impellers (7); the screw (4) is threadedly connected to the threaded holes; a through hole is provided at the center of the pressure plate (6) in the longitudinal direction, and the pressure plate (6) is sleeved on the outer periphery of the screw (4) through the through hole, and the two ends of the pressure plate (6) respectively press the upper ends of the two three-blade impellers (7); the pressing nut (5) is threadedly connected to the screw (4) and presses the pressure plate (6) from above.

7. A Roots blower impeller machining auxiliary positioning method, characterized in that: When the center hole (11) and the lightening hole (10) of the three-blade impeller (7) are milled and the balancing hole is drilled, the auxiliary positioning using the Roots blower impeller processing auxiliary positioning device according to claim 6 comprises the following steps: Step 1: Select the base (1) and determine the installation position of the support (2) according to the specifications of the three-blade impeller (7), and determine the endpoint coordinates of the horizontal projection of the base (1) on the working platform; then detachably connect multiple supports (2) to the base (1); Step 2: placing two cast three-blade impellers (7) on the upper surface of the base (1), and clamping the end of each three-blade impeller (7) by a pair of linear telescopic devices (3); after clamping, the end faces of the two three-blade impellers (7) are flush, and a distance y1 is obtained from the end face of the three-blade impeller (7) close to the tool to the base (1); after clamping, the lengths of the two linear telescopic devices (3) on the same side of the three-blade impeller (7) are the same, and the lengths of the pair of linear telescopic devices (3) are x1 and x2 respectively; Step 3: Using a pressing mechanism to press and fix the upper ends of the two three-blade impellers (7); Step 4: Using the known height h of the base (1), the thickness t of the support (2), the outer radius r of each blade of the three-blade impeller (7), and the above-mentioned y1, x1, and x2, the axis end point coordinates of the center hole (11), the lightening hole (10), and the balancing hole of the three-blade impeller (7) are calculated respectively; Step 5: Input the axis endpoint coordinates of the center hole (11), the lightening hole (10) and the balancing hole through the coordinate operation screen of the CNC machine tool, and then use a milling tool to perform milling and a drilling tool to perform drilling according to the input coordinates.

8. The Roots blower impeller machining auxiliary positioning method according to claim 7, characterized in that: In step one, the number of branch bases in the base (1) is determined according to the axial length of the three-blade impeller (7), and the spacing between the front base and the rear base is adjusted to ensure that the lengths of the end cantilevered portion and the middle cantilevered portion of the three-blade impeller (7) are less than 40 mm respectively; and a group of connecting holes (9) connected to the support (2) is determined according to the diameter of the three-blade impeller (7).

9. The Roots blower impeller machining auxiliary positioning method according to claim 7, characterized in that: The two weight-reducing holes (10) at the lower part of the three-blade impeller (7) are weight-reducing hole 1 and weight-reducing hole 2; The X-axis coordinate of the endpoint of the axis of the first lightening hole is obtained by adding the endpoint coordinate of the horizontal projection of the base (1) on the working platform to the thickness t of the support (2), x1, and the outer radius r of the blade; the Y-axis coordinate of the endpoint of the axis of the first lightening hole is obtained by subtracting the length y1 of the overhanging portion of the end of the three-blade impeller (7) from the endpoint coordinate of the horizontal projection of the base (1) on the working platform; and the Z-axis coordinate of the endpoint of the axis of the first lightening hole is obtained by adding the height h of the base (1) to the outer radius r of the blade. The Y coordinate of the endpoint of the axis of the second weight-reducing hole is the same as the Y coordinate of the endpoint of the axis of the first weight-reducing hole, and the Z coordinate of the endpoint of the axis of the second weight-reducing hole is the same as the Z coordinate of the endpoint of the axis of the first weight-reducing hole; the X coordinate of the endpoint of the axis of the second weight-reducing hole is obtained by adding the endpoint coordinate of the horizontal projection of the base (1) on the working platform to the distance between two adjacent supports (2), then subtracting x2, and then subtracting the outer end radius r of the blade.

10. The Roots blower impeller machining auxiliary positioning method according to claim 9, characterized in that: The weight-reducing hole (10) on the upper part of the three-blade impeller (7) is weight-reducing hole three; the axial end points of the weight-reducing hole three, the center hole (11) and the balancing hole and the axial end points of the weight-reducing hole one and the weight-reducing hole two form a triangle, and the coordinates of the axial end points of the weight-reducing hole three, the center hole (11) and the balancing hole can be obtained through triangle geometry calculation.

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