Device and method for detecting radial rigidity of air bearing main shaft

Abstract

The invention discloses a device and method for detecting the radial rigidity of an air floating main shaft, and the device comprises a pedestal, a first main shaft fixing frame, a second main shaft fixing frame, a force sensor fixing frame, a plurality of fixing blocks, a displacement sensor, and a force sensor. Wherein a plurality of sliding grooves are formed in the base, and the plurality of fixing blocks are respectively accommodated in the sliding grooves; a first threaded hole is formed in the top of each fixing block, and the first main shaft fixing frame, the second main shaft fixing frame and the force sensor fixing frame are fixedly connected with the base through the first threaded holes; an air floating main shaft to be detected is fixedly connected between the first main shaft fixing frame and the second main shaft fixing frame; the displacement sensor is fixed on the first main shaft fixing frame or the second main shaft fixing frame and is used for detecting the radial displacement of the air floating main shaft to be detected; the force sensor is fixed on the top of the force sensor fixing frame and abuts against the to-be-detected air floating main shaft, so that the force sensor is used for detecting the radial force applied to the to-be-detected air floating main shaft.

Description

Technical Field

[0001] The invention relates to the field of spindle detection, and in particular to a radial stiffness detection device and method for an air-floating spindle. Background Art

[0002] With the rapid development of industries such as aerospace, semiconductor manufacturing, and precision optical instruments, the requirements for efficient and high-quality processing of hard and brittle materials are becoming increasingly higher. In order to further improve the rotation accuracy of the spindle, reduce the size of the spindle, and reduce the oil mist pollution generated during the use of the spindle, more and more air-driven air-floating spindles are beginning to be used in ultra-precision machining. Compared with traditional mechanical contact electric spindles, air-driven air-floating spindles have the advantages of high precision, easy processing, easy assembly, and no pollution, which is also the key to improving the accuracy of ultra-precision machining.

[0003] The overall radial stiffness of the air-floating spindle directly affects the machining accuracy and product quality. High radial stiffness can reduce the deformation of the spindle caused by load or torque changes during machining, thereby ensuring machining accuracy. Insufficient radial stiffness of the spindle may lead to reduced workpiece machining accuracy and even vibration and unstable machining conditions.

[0004] Therefore, there is an urgent need to provide a spindle radial stiffness detection solution that is fast, convenient, efficient, accurate, economical, and compatible with multiple models. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a radial stiffness detection device and method for an air-bearing spindle that overcomes the above problems or at least partially solves the above problems.

[0006] According to one aspect of the present invention, a radial stiffness detection device for an air-floating spindle is provided, comprising: a base, a first spindle fixing frame, a second spindle fixing frame, a force sensor fixing frame, a plurality of fixing blocks, a displacement sensor and a force sensor; wherein a plurality of sliding grooves are formed on the base, and the fixing blocks are respectively accommodated in the sliding grooves; a first threaded hole is arranged on the top of each fixing block, and the first spindle fixing frame, the second spindle fixing frame and the force sensor fixing frame are fixedly connected to the base through the first threaded hole; the air-floating spindle to be detected is fixedly connected between the first spindle fixing frame and the second spindle fixing frame; the displacement sensor is fixed on the first spindle fixing frame or the second spindle fixing frame, and is used to detect the radial displacement of the air-floating spindle to be detected; the force sensor is fixed on the top of the force sensor fixing frame, and is in contact with the air-floating spindle to be detected, and the radial force applied to the air-floating spindle to be detected is transmitted to the air-floating spindle to be detected through the force sensor, so that the radial force applied to the air-floating spindle to be detected is detected by using the force sensor.

[0007] Optionally, in the device according to the present invention, multiple groups of second threaded holes are formed on the side of the first spindle fixing frame or the second spindle fixing frame away from the base, wherein any group of second threaded holes is compatible with a type of air-floating spindle; the air-floating spindle to be tested is fixedly connected between the first spindle fixing frame and the second spindle fixing frame through the second threaded holes.

[0008] Optionally, in the device according to the present invention, the force sensor fixing frame includes: a support plate, a fixing plate and a rib plate; the fixing plate is vertically fixed to the support plate; the rib plate is configured as a right triangle, and its two mutually perpendicular side surfaces are respectively abutted against the support plate and the fixing plate, so as to reduce the deformation of the force sensor fixing frame caused by the radial force.

[0009] Optionally, in the device according to the present invention, a plurality of third threaded holes of different heights are arranged on one side of the fixing plate away from the supporting plate, for fixing the force sensor by selecting a corresponding third threaded hole according to the height of the air-bearing spindle to be detected.

[0010] Optionally, in the device according to the present invention, the force sensor fixing frame also includes: a connecting plate, including a plurality of fourth threaded holes for fixing the support plate and a plurality of fifth threaded holes for connecting the base; the plurality of fourth threaded holes are arranged in an array, and by adjusting the fourth threaded holes fixed to the support plate, the distance between the force sensor and the air-floating main axis to be detected can be adjusted accordingly; the plurality of fifth threaded holes are distributed at the corners of the connecting plate, and the force sensor bracket is fixed to the base through the fifth threaded holes and the corresponding first threaded holes.

[0011] Optionally, in the device according to the present invention, the first spindle fixing frame or the second spindle fixing frame is made of a magnetically attractive metal material, and the displacement sensor is fixed to the first spindle fixing frame or the second spindle fixing frame by magnetic attraction.

[0012] Optionally, in the device according to the present invention, the stiffness of the air-bearing main shaft to be detected is the ratio of radial force to radial displacement.

[0013] Optionally, in the device according to the present invention, each sliding groove is laid in parallel on the base, and the sliding groove is a T-shaped groove.

[0014] Optionally, in the device according to the present invention, the fixing block is step-shaped, and the fixing block can slide in the sliding groove.

[0015] Optionally, the device according to the present invention further includes a magnetic stand, including a magnetic base and an adjustable bracket, the displacement sensor is mounted on a side of the adjustable bracket away from the magnetic base, and the magnetic base is fixed to the first spindle fixing frame or the second spindle fixing frame by a magnetic connection.

[0016] According to another aspect of the present invention, there is provided a method for detecting the radial stiffness of an air-floating spindle, which is performed by the above-mentioned device, and the method comprises: determining the positions of a first spindle fixing frame, a second spindle fixing frame and a force sensor bracket based on the model of the air-floating spindle to be detected, and fixing the first spindle fixing frame, the second spindle fixing frame and the force sensor bracket by using fixing blocks, and fixing the air-floating spindle to be detected between the first spindle fixing frame and the second spindle fixing frame; applying a radial force to the air-floating spindle to be detected; recording data of the force sensor and the displacement sensor, and calculating the stiffness of the air-floating spindle to be detected based on the recorded data.

[0017] Optionally, in the method according to the present invention, calculating the stiffness of the air-bearing spindle to be detected based on the recorded data includes: taking the ratio of the radial force recorded by the force sensor to the radial displacement recorded by the displacement sensor as the stiffness of the air-bearing spindle to be detected.

[0018] According to the scheme of the present invention, the structure is simple and compact, easy to control, and only simple tooling is needed to conveniently and quickly detect the overall radial stiffness of the spindle, and it is compatible with two or more spindles. The difficulty and cost of detecting the overall radial stiffness are greatly reduced, and it is suitable for measuring the overall radial stiffness of the spindle in engineering.

[0019] In addition, according to the solution of the present invention, fixing threaded holes matching different types of spindles are arranged on the first spindle fixing frame and the second spindle fixing frame, so that compatibility with at least two or more types of spindles can be achieved.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0022] Figure 1 A schematic structural diagram of a radial stiffness detection device 100 for an air-bearing spindle according to an embodiment of the present invention is shown;

[0023] Figure 2 A schematic structural diagram of a fixing block 150 according to an embodiment of the present invention is shown;

[0024] Figure 3A schematic diagram of the AA cross section of a first spindle fixing frame 120 according to an embodiment of the present invention is shown;

[0025] Figure 4 shows a front view of a second spindle mount 130 according to one embodiment of the present invention;

[0026] Figure 5 A schematic structural diagram of a magnetic table stand 180 according to an embodiment of the present invention is shown;

[0027] Figure 6 It shows a schematic structural diagram of a force sensor fixing bracket 140 according to an embodiment of the present invention;

[0028] Figure 7 A schematic structural diagram of a force sensor 170 according to an embodiment of the present invention is shown;

[0029] Figure 8 A schematic structural diagram of a connecting plate 145 according to an embodiment of the present invention is shown;

[0030] Fig. 9 A schematic flow chart of a method 300 for detecting radial stiffness of an air-bearing spindle according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0032] The existing spindle radial stiffness detection device has the following problems:

[0033] 1. Complex structure, high manufacturing and maintenance costs;

[0034] 2. The equipment has poor adaptability, is difficult to adjust, and cannot flexibly cope with spindles of different sizes or shapes;

[0035] 3. The design lacks specificity;

[0036] 4. The operation is cumbersome and requires complicated debugging and calibration process;

[0037] 5. The device structure design does not match the stiffness detection requirements.

[0038] 6. It is impossible to simplify the device structure while ensuring the measurement accuracy and taking into account the cost and operational convenience of the equipment.

[0039] In order to solve the problems existing in the above-mentioned prior art, the solution of the present invention is proposed. This application proposes a radial stiffness detection device for an air-floating spindle. The device has a simple and compact structure and is easy to control. It only requires simple tooling to conveniently and quickly detect the overall radial stiffness of the spindle, and is compatible with two or more spindles. The difficulty and cost of detecting the overall radial stiffness are greatly reduced, and it is suitable for measuring the overall radial stiffness of the spindle in engineering.

[0040] Figure 1 A schematic structural diagram of a radial stiffness detection device 100 for an air-bearing spindle according to an embodiment of the present invention is shown. Figure 2 FIG. 1 is a schematic structural diagram of a fixing block 150 according to an embodiment of the present invention. Figure 3 FIG. 1 is a schematic cross-sectional view of a first spindle fixing frame 120 according to an embodiment of the present invention.

[0041] Figure 4 A front view of a second spindle mount 130 according to one embodiment of the present invention is shown. Figure 5 A schematic structural diagram of a magnetic stand 180 according to an embodiment of the present invention is shown. Figure 6 FIG. 1 is a schematic structural diagram of a force sensor fixing bracket 140 according to an embodiment of the present invention. Figure 7 FIG. 1 is a schematic structural diagram of a force sensor 170 according to an embodiment of the present invention. Figure 8 FIG. 1 is a schematic structural diagram of a connecting plate 145 according to an embodiment of the present invention.

[0042] like Figure 1-8 As shown, the device 100 includes a base 110 , a first spindle fixing frame 120 , a second spindle fixing frame 130 , a force sensor fixing frame 140 , a plurality of fixing blocks 150 , a displacement sensor 160 , a force sensor 170 and a magnetic table base 180 .

[0043] A plurality of sliding grooves 111 are formed on the base 110 , and each fixing block 150 is respectively accommodated in the sliding groove 111 . The fixing blocks 150 are used to fix the force sensor fixing frame 140 , the first spindle fixing frame 120 and the second spindle fixing frame 130 on the base 110 .

[0044] like Figure 2As shown, the fixing block 150 is in a step shape, and accordingly, the sliding groove 111 is a T-shaped groove, and the fixing block 150 is embedded in the sliding groove 111 from one side of the sliding groove 111. The overall size of the fixing block 150 is slightly smaller than the sliding groove 111, for example, the size of the fixing block 150 is 1 to 2 mm smaller than the sliding groove 111, so that the fixing block 150 can be easily moved in the sliding groove 111. Because the sliding groove 111 is narrow at the top and wide at the bottom, the step-shaped fixing block 150 is stuck in the sliding groove 111 and can only move along the groove direction of the sliding groove 111, but cannot move in the up and down direction (direction close to or away from the base 110).

[0045] In this way, air-bearing spindles of different lengths can be adapted to detect various types of air-bearing spindles, greatly reducing the detection cost of the overall radial stiffness.

[0046] A first threaded hole 151 is arranged at the top of the fixing block 150, and correspondingly, threaded holes are also arranged at the bottom of the first spindle fixing frame 120 and the second spindle fixing frame 130. The two are fixed by the threaded holes at the top of the fixing block 150 and the threaded holes at the bottom of the first spindle fixing frame 120 (or the second spindle fixing frame 130).

[0047] like Figure 3 and Figure 4 As shown, the first spindle fixing frame 120 or the second spindle fixing frame 130 is a structure that is narrow at the top and wide at the bottom, so as to better bear the radial force on the air-floating spindle 200 to be detected during detection. A plurality of groups of second threaded holes 121 (or 131) are formed on the upper part (the side away from the base 110) of the first spindle fixing frame 120 or the second spindle fixing frame 130, and any group of second threaded holes 121 (or 131) is adapted to a type of air-floating spindle, so that at least two or more types of air-floating spindles 200 to be detected can be connected to the first spindle fixing frame 120 or the second spindle fixing frame 130 through the second threaded holes 121 (or 131). The second threaded holes 121 (or 131) that match the air-floating spindles 200 to be detected of different types are arranged on the first spindle fixing frame 120 and the second spindle fixing frame 130, so that at least two or more types of air-floating spindles 200 to be detected can be detected.

[0048] In some embodiments, each group of second threaded holes 121 (or 131) is coaxially arranged and alternately distributed at 30° with each other to better support the air-bearing spindle 200 to be tested.

[0049] The displacement sensor 160 is fixed on the top of the first spindle fixing frame 120 or the second spindle fixing frame 130 to measure the small deformation caused by the force on the detected air-bearing spindle 200. In some embodiments, the first spindle fixing frame 120 or the second spindle fixing frame 130 is a magnetically attractive metal material, and the displacement sensor 160 is fixed on the first spindle fixing frame 120 or the second spindle fixing frame 130 by magnetic attraction.

[0050] In some embodiments, the displacement sensor 160 is fixed on the top of the first spindle fixing frame 120 or the second spindle fixing frame 130 through a magnetic base 180. Figure 5 As shown, the magnetic stand 180 includes a magnetic base 181 and an adjustable bracket 182. The magnetic base 181 is fixed to the first spindle fixing frame 120 or the second spindle fixing frame 130 by means of magnetic connection. The adjustable bracket 182 is divided into a bracket portion 1821 and a clamping portion 1822. The clamping portion 1822 is arranged at a position of the adjustable bracket 182 away from the magnetic base 181, and can be used to clamp and fix the displacement sensor 160. The bracket portion 1821 can be retracted to adjust the position of the displacement sensor 160.

[0051] like Figure 6 As shown, the force sensor fixing frame 140 includes a support plate 141, a fixing plate 142 and a rib plate 143. The support plate 141 and the fixing plate 142 are fixed vertically. The rib plate 143 is configured as a right triangle, and its two mutually perpendicular sides are fixedly connected to the support plate 141 and the fixing plate 142 respectively, so as to reduce the slight deformation of the force sensor bracket when the radial force is applied to the main shaft, thereby reducing the measurement error. The support plate 141, the fixing plate 142 and the rib plate 143 are connected to each other by screws to reduce the difficulty of processing and reduce the cost.

[0052] like Figure 7 As shown, a plurality of third threaded holes 144 of different heights are arranged at the top of the fixing plate 142 (the side away from the base 110 or the side close to the air-floating spindle 200 to be detected), and the force sensor 170 is fixed between the fixing plate 142 and the air-floating spindle 200 to be detected through the third threaded holes 144, and the force sensor 170 is in contact with the air-floating spindle 200 to be detected.

[0053] The third threaded holes 144 are arranged at intervals according to the suspension height of the air bearing spindle 200 to be tested of different models, so that a reasonable threaded hole 144 can be selected to install the force sensor 170. In some embodiments, the intervals between the third threaded holes 144 are 10 mm to 15 mm.

[0054] like Figure 8As shown, the force sensor bracket 140 further includes a connecting plate 145 disposed between the supporting plate 141 and the base 110 , and the connecting plate 145 is provided with a plurality of fourth threaded holes 146 for connecting to the supporting plate 141 and a plurality of fifth threaded holes 147 for connecting to the base 110 .

[0055] The plurality of fourth threaded holes 146 are divided into two rows and arranged symmetrically (array arrangement). By selecting different fourth threaded holes 146 to connect with the support plate 141 , the distance between the force sensor 170 and the air-bearing spindle 200 to be detected can be adjusted accordingly.

[0056] A plurality of fifth threaded holes 147 are distributed at corners of the connecting plate 145 , and the force sensor bracket 140 is fixed to the base 110 through the fifth threaded holes 147 and the corresponding first threaded holes 151 on the fixing block 150 .

[0057] When the device 100 is working, the radial force to the air-floating spindle 200 to be detected is transmitted to the air-floating spindle 200 to be detected through the force sensor 170, so that the force sensor 170 can record the value of the radial force, and then the radial displacement of the air-floating spindle 200 to be detected is recorded through the displacement sensor 160, so that the radial stiffness of the air-floating spindle 200 to be detected can be calculated.

[0058] Specifically, the stiffness of the air-bearing main shaft 200 to be tested is the ratio of the radial force to the radial displacement.

[0059] The device 100 provided in this embodiment has a simple and compact structure and is easy to control. It only needs simple tooling to conveniently and quickly detect the overall radial stiffness of the spindle, and is compatible with two or more spindles. The difficulty and cost of detecting the overall radial stiffness are greatly reduced, and it is suitable for measuring the overall radial stiffness of the spindle in engineering. In addition, fixed threaded holes matching different types of spindles 200 are arranged on the first spindle fixing frame 120 and the second spindle fixing frame 130, so that compatibility with at least two or more spindles can be achieved.

[0060] Fig. 9 The flowchart of a method 300 for detecting radial stiffness of an air-bearing spindle according to an embodiment of the present invention is shown. The method 300 is suitable for being executed by the above-mentioned device 100 .

[0061] Method 300 is suitable for step 302. In step 302, based on the model of the air-floating spindle 200 to be detected, the positions of the first spindle fixing frame 120, the second spindle fixing frame 130 and the force sensor bracket 140 are determined, and the first spindle fixing frame 120, the second spindle fixing frame 130 and the force sensor bracket 140 are fixed by using the fixing blocks 150, and the air-floating spindle 200 to be detected is fixed between the first spindle fixing frame 120 and the second spindle fixing frame 130.

[0062] Specifically, the first spindle fixing frame 120 is first fixed on the base 110 , and then the position of the second spindle fixing frame 130 is determined according to the length of the air-bearing spindle 200 to be detected, and the second spindle fixing frame 130 is fixed on the base 110 .

[0063] Then, the force sensor fixing frame 140 is fixed on the base 110. According to the distance between the force sensor 170 and the air-bearing spindle 200 to be detected (so that the force sensor 170 and the air-bearing spindle 200 to be detected just abut), the fourth threaded hole 146 for connecting the support plate 141 and the connecting plate 145 is determined. And according to the hanging height of the air-bearing spindle 200 to be detected, a suitable third threaded hole 144 is selected, and the force sensor 170 is fixed to the force sensor fixing frame 140 by using the selected third threaded hole 144.

[0064] Before executing step 302, it is necessary to inspect each component of the device 100. Specifically, check whether each component has burrs, and focus on inspecting the first spindle fixing frame 120 and the second spindle fixing frame 130 to prevent burrs from scratching the air-floating spindle 200 to be inspected. Also, check whether each threaded hole is complete and whether there are enough screws.

[0065] After inspecting each component, the components are assembled in sequence to obtain an assembled device 100 .

[0066] The displacement sensor 160 is fixed on the first spindle fixing frame 120 or the second spindle fixing frame 130 by magnetic attraction.

[0067] Then, in step 304 , radial force is applied to the air-bearing spindle 200 to be tested. For example, the radial force is applied to the air-bearing spindle 200 to be tested by rotating the screws connecting the force sensor 170 and the fixing plate 142 .

[0068] Finally, in step 306, the data of the force sensor 170 and the displacement sensor 160 are recorded, and the stiffness of the air-bearing spindle 200 to be tested is calculated based on the recorded data. Specifically, the ratio of the radial force recorded by the force sensor 170 and the radial displacement recorded by the displacement sensor 160 is used as the stiffness of the air-bearing spindle 200 to be tested.

[0069] It should be noted that the working principle and process of the method 300 provided in this embodiment are similar to those of the above-mentioned device 100. For relevant details, reference may be made to the description of the above-mentioned device 100, which will not be repeated here.

[0070] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0071] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is meant to be within the scope of the present invention and to form different embodiments.

[0072] As used herein, unless otherwise specified, the use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved, and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0073] A9. The device as described in A8, wherein the fixed block is step-shaped and can slide in the sliding groove. B12. The method as described in B11, wherein the stiffness of the air-floating spindle to be tested is calculated based on the recorded data, including: taking the ratio of the radial force recorded by the force sensor and the radial displacement recorded by the displacement sensor as the stiffness of the air-floating spindle to be tested.

[0074] Although the present invention has been described in terms of a limited number of embodiments, it will be apparent to those skilled in the art, having benefit of the above description, that other embodiments are contemplated within the scope of the invention thus described. Furthermore, it should be noted that the language used in this specification is selected primarily for readability and didactic purposes, rather than for the purpose of explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims.

Claims

1. A radial stiffness detection device for an air-floating spindle, comprising: A base, a first spindle fixing frame, a second spindle fixing frame, a force sensor fixing frame, a plurality of fixing blocks, a displacement sensor and a force sensor; Wherein, a plurality of sliding grooves are formed on the base, and the fixing blocks are respectively accommodated in the sliding grooves; A first threaded hole is arranged on the top of each of the fixing blocks, and the first spindle fixing frame, the second spindle fixing frame and the force sensor fixing frame are fixedly connected to the base through the first threaded hole; The air-floating spindle to be tested is fixedly connected between the first spindle fixing frame and the second spindle fixing frame; The displacement sensor is fixed on the first spindle fixing frame or the second spindle fixing frame, and is used to detect the radial displacement of the air-bearing spindle to be detected; The force sensor is fixed on the top of the force sensor fixing frame and abuts against the outer shell of the air-floating spindle to be detected. The radial force applied to the air-floating spindle to be detected is transmitted to the air-floating spindle to be detected through the force sensor, so that the radial force applied to the air-floating spindle to be detected can be detected by using the force sensor.

2. The device according to claim 1, wherein: A plurality of groups of second threaded holes are formed on a side of the first spindle fixing frame or the second spindle fixing frame away from the base, wherein any group of second threaded holes is compatible with a type of air-floating spindle; The air-bearing spindle to be detected is fixedly connected between the first spindle fixing frame and the second spindle fixing frame through the second threaded hole.

3. The device according to claim 1, wherein: The force sensor fixing frame comprises: Support plates, fixing plates and ribs; The fixing plate is vertically fixed to the supporting plate; The rib plate is configured as a right triangle, and its two mutually perpendicular side surfaces are respectively in contact with the support plate and the fixing plate, so as to reduce the deformation of the force sensor fixing frame caused by the radial force.

4. The device as claimed in claim 3, wherein: A plurality of third threaded holes with different heights are arranged on one side of the fixing plate away from the supporting plate, and are used to fix the force sensor by selecting a corresponding third threaded hole according to the height of the air-bearing spindle to be detected.

5. The device as claimed in claim 3, wherein: The force sensor fixing bracket also includes: a connecting plate, comprising a plurality of fourth threaded holes for fixing the support plate and a plurality of fifth threaded holes for connecting the base; The plurality of fourth threaded holes are arranged in an array, and the distance between the force sensor and the air-floating spindle to be detected can be adjusted accordingly by adjusting the fourth threaded holes fixed to the support plate; A plurality of the fifth threaded holes are distributed at the corners of the connecting plate, and the force sensor bracket is fixed to the base through the fifth threaded holes and the corresponding first threaded holes.

6. The device according to claim 1, wherein: The first spindle fixing frame or the second spindle fixing frame is made of a magnetically attractive metal material, and the displacement sensor is fixed on the first spindle fixing frame or the second spindle fixing frame by magnetic attraction.

7. The device of claim 1, wherein: The stiffness of the air-bearing spindle to be tested is the ratio of radial force to radial displacement.

8. The device of claim 1, wherein: Each of the sliding grooves is laid in parallel on the base, and the sliding grooves are T-shaped grooves.

9. The device as described in claim 6 further includes a magnetic stand, including a magnetic base and an adjustable bracket, the displacement sensor is supported on a side of the adjustable bracket away from the magnetic base, and the magnetic base is fixed to the first spindle fixing frame or the second spindle fixing frame by a magnetic connection.

10. A method for detecting radial stiffness of an air-bearing spindle, performed by the device according to any one of claims 1 to 9, the method comprising: Based on the model of the air-bearing spindle to be detected, the positions of the first spindle fixing frame, the second spindle fixing frame and the force sensor bracket are determined, and the first spindle fixing frame, the second spindle fixing frame and the force sensor bracket are fixed by using the fixing blocks, and the air-bearing spindle to be detected is fixed between the first spindle fixing frame and the second spindle fixing frame; Applying radial force to the air-bearing spindle to be tested; The data of the force sensor and the displacement sensor are recorded, and the stiffness of the air-bearing spindle to be tested is calculated based on the recorded data.

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