A screw heat elongation detection device and method

Abstract

The application discloses a screw heat elongation detection device and method, and belongs to the technical field of parts, components or accessories of machine tools. The device comprises a displacement detection assembly, the displacement detection assembly comprises a displacement detection ring and a displacement sensor, the displacement detection ring is installed on a screw, and the displacement sensor is arranged on one side of the screw and faces the displacement detection ring. The screw comprises a head section, a threaded section and a tail section, which are integrally formed, and the displacement detection assembly is arranged at the two ends of the threaded section and the tail end of the tail section. The application can be used for accurate measurement of the elongation of a hollow water-cooled screw feeding system, high-precision displacement detection assemblies are arranged at the starting end of the screw thread, the ending end of the screw thread and the tail end of the screw, and the displacement of the screw during high-speed rotation can be accurately measured.

Description

Technical Field

[0001] This invention relates to a lead screw testing device and method, and more particularly to a lead screw thermal elongation testing device and method, belonging to the technical field of machine tool parts, components or accessories. Background Technology

[0002] In recent years, with the continuous improvement of the overall technological level of the equipment manufacturing industry, the performance requirements for ball screw pairs—key components in CNC machine tools, precision instruments, and various precision mechanical equipment—have become increasingly stringent. Among them, hollow water-cooled ball screw feed systems are mainly used in precision or ultra-precision machine tools. The elongation of the ball screw due to temperature changes caused by frictional heat is an important factor affecting the positioning and machining accuracy of precision CNC machine tools and is an important indicator reflecting the performance of the machine tool.

[0003] Suppressing the thermal expansion of the hollow water-cooled lead screw feed system plays a very important role in improving the accuracy of machine tools. However, there are currently few measuring devices and methods for the thermal expansion of hollow water-cooled lead screws, and the measurements are not accurate enough, making it impossible to accurately optimize the cooling parameters of the lead screw.

[0004] One existing method for detecting the thermal elongation of lead screws is to measure the screw temperature and then use a fitted model to predict the amount of thermal elongation. However, in hollow-cooled lead screw feeding systems, the screw has a forced active cooling channel, resulting in rapid and uneven temperature changes. Furthermore, the temperature differences between different parts of the screw during thermal deformation are significant. Since temperature sensors are limited by space constraints and can only be placed in non-interference locations, it is impossible to comprehensively assess the overall temperature change of the lead screw. Additionally, inconsistent temperatures at different locations on the lead screw lead to varying amounts of thermal elongation. Therefore, models that predict the overall elongation of the lead screw based on localized temperature changes have significant errors. Moreover, if temperature is measured using an infrared thermal imager, a suitable measurement environment is required, but this is often affected by the surface quality of the side surfaces and lighting conditions, resulting in low measurement accuracy and poor consistency. Therefore, this method cannot accurately detect the temperature rise of the lead screw, and its stability limits its application. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The technical problem to be solved by this invention is to address the current lack of effective devices and methods for detecting the thermal elongation of hollow cooling screws, which makes it impossible to accurately determine the impact of the thermal elongation of the screw on the positioning accuracy and repeatability of machine tools during operation.

[0007] (II) Technical Solution

[0008] To address the aforementioned technical problems, this invention provides a lead screw thermal elongation detection device, which can be used for lead screw thermal elongation detection and also for lead screw displacement detection. The device includes a displacement detection assembly comprising a displacement detection ring and a displacement sensor. The displacement detection ring is mounted on the lead screw, and the displacement sensor is positioned on one side of the lead screw, directly opposite the displacement detection ring. The lead screw comprises a head section, a threaded section, and a tail section, all integrally formed. The displacement detection assembly is respectively installed at both ends of the threaded section and at the tail end of the tail section. This structure, with high-precision displacement detection assemblies at the beginning, end, and tail ends of the lead screw thread, enables accurate measurement of the lead screw displacement during high-speed rotation.

[0009] Furthermore, the displacement detection ring includes a clamping sleeve, a measuring ring, an adjusting screw, a spherical washer, and a butterfly spring. The clamping sleeve is mounted on the lead screw, and the measuring ring is mounted on one side of the clamping sleeve. The two are connected by an adjusting screw, the head of which is fitted with a spherical washer. A butterfly spring is mounted on the adjusting screw located between the clamping sleeve and the measuring ring. Through this structure, adjusting the preload of the adjusting screw controls the surface runout of the measuring ring within 1 μm, ensuring that the runout of the measured surface reaches the required accuracy during rotation, guaranteeing that the displacement sensor reading accurately represents the state of the lead screw. This also solves the problem of excessive errors in the measured surface caused by lead screw deflection and deformation, as well as the machining and installation of the measuring ring.

[0010] Furthermore, the clamping sleeve has an arc-shaped end near the measuring ring, and the measuring ring has a tapered hole. The arc-shaped end is inserted into the tapered hole, and the arc-shaped surface of the arc-shaped end abuts against the inclined surface of the tapered hole. This facilitates angular rotation between the two.

[0011] Furthermore, it also includes a detection bracket, wherein the detection bracket has a coefficient of thermal expansion not exceeding 1.2 × 10⁻⁶. -6 It is made of a material with a temperature of / K, making it virtually unaffected by environmental and system temperatures, effectively improving the accuracy and consistency of measurement data. At room temperature, the axial thermal expansion coefficient of carbon fiber is approximately -0.5 × 10⁻⁶. -6 to -1.0×10 -6 Between these values, the coefficient of thermal expansion of indium steel is approximately 1.2 × 10⁻⁶. -6 / K, the main components of the machine tool base are usually made of gray cast iron. Taking HT300 as an example, it is usually about 10.5×10 -6 / K to 12.5×10 -6 / K, the coefficient of thermal expansion of the lead screw, taking GCr15 as an example, is approximately 12.0 × 10⁻⁶. -6 / K to 13.5×10 -6 / K.

[0012] Furthermore, the detection bracket includes a support and a support rod. The support rod is provided on one side of the lead screw, and a combination seat is provided on the support rod. A dial indicator is provided on the combination seat. The displacement sensors of the displacement detection components at both ends of the threaded section and the tail end of the lead screw are respectively mounted on the support rod through the dial indicator. The support is provided at both ends of the support rod.

[0013] Furthermore, a slide rail is provided at the tail end of the support rod, and a slider is slidably connected to the slide rail. A support is fixed at one end of the support rod, and a support at the other end is mounted on the slider. This allows the support rod to extend and retract along the feed direction while restricting movement in other degrees of freedom. It also allows the installation position of the tail end of the support rod to move when the machine tool deforms. Assuming the detection bracket (or both ends of the support rod) is completely fixed to the machine bed with screws, the thermal deformation of the machine bed will differ from the thermal deformation of the detection bracket (or support rod). Due to this discrepancy in elongation, relative deformation will occur between the two, leading to increased measurement errors.

[0014] Furthermore, the support includes a base body, a cylindrical expansion sleeve, a conical expansion sleeve, and a tensioning screw. The base body has a support hole, and the end of the support rod is inserted into the support hole. The cylindrical expansion sleeve and the conical expansion sleeve are disposed within the support rod located in the support hole. The cylindrical expansion sleeve has a conical sleeve hole, and the cylindrical expansion sleeve at the conical sleeve hole has multiple open slots. The conical expansion sleeve is inserted into the conical sleeve hole. The tensioning screw passes through the base body and connects to the conical expansion sleeve. This structure enables a tight and reliable connection between the support and the support rod.

[0015] Furthermore, the head section and tail section of the lead screw are respectively provided with a motor base and a lead screw base. The lead screw base is provided with a spacer and a bearing. The outer end of the bearing is provided with a pressure cap, a displacement detection ring, a locking nut, an end cap and a sealing cap in sequence. The pressure cap is provided with a cavity to accommodate the displacement detection ring. The pressure cap and the end cap are respectively provided with a clearance opening and a notch for receiving the displacement sensor. The clamping sleeves at both ends of the threaded section of the lead screw are both split structures that are locked with screws, while the clamping sleeve at the lead screw base is an integral structure.

[0016] On the other hand, the present invention also provides a detection method for a lead screw thermal elongation detection device, specifically: a worktable is set on the lead screw (the worktable is placed on the machine tool bed), and then the worktable is moved back and forth to make the lead screw reach a thermal equilibrium state. The displacement of the corresponding displacement detection ring is measured by displacement sensors at both ends of the lead screw thread section and the tail end of the tail section. The values ​​are L1, L2 and L3 in sequence, where L1 is the thermal elongation of the lead screw head section, L2 is the thermal elongation of the lead screw thread section and head section, L3 is the thermal elongation of the lead screw as a whole, L2-L1 is the thermal elongation of the lead screw thread section, and L3-L2 is the thermal elongation of the lead screw tail section.

[0017] Furthermore, when measuring the thermal elongation of the lead screw from a cold state to a thermal equilibrium state, the worktable is moved from the motor base, with an overtravel of 0.1 mm each time, so that the movement is directed towards the lead screw base. After data acquisition, the lead screw is continued to run, and this cycle is repeated to measure the thermal elongation of the lead screw from a cold state to a thermal equilibrium state.

[0018] (III) Beneficial Effects

[0019] The above-described technical solution of the present invention has the following advantages:

[0020] (1) This invention can be used to accurately measure the elongation of the screw in a hollow water-cooled screw feed system. High-precision displacement detection components are provided at the beginning end, end end and tail end of the screw thread, which can measure the displacement of the screw as a whole and each sub-segment during high-speed rotation.

[0021] (2) The displacement detection ring of the present invention, through the combination of a clamping sleeve, a measuring ring, an adjusting screw, a spherical washer, and a disc spring, can adjust the preload of the adjusting screw to control the surface runout of the measuring ring within 1 μm, so that the runout of the measured surface reaches the required accuracy during rotation, ensuring that the reading of the displacement sensor can truly represent the state of the lead screw. The displacement detection ring structure of the present invention can also solve the problem of excessive error of the measured surface caused by lead screw deflection and deformation and the processing and installation of the measuring ring.

[0022] (3) The coefficient of thermal expansion of the test stent material of this invention is not higher than 1.2 × 10⁻⁶. -6 / K, which is basically unaffected by temperature changes, ensures that the measurement reference of the displacement sensor is consistent with the reference of the lead screw, and is not affected by temperature changes during operation. This guarantees that the position of the displacement sensor is not affected by the ambient and system temperature, and can effectively improve the accuracy and consistency of measurement data.

[0023] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted by the present invention, and the advantages brought about by the technical features of these technical solutions as described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a front view schematic diagram of the present invention mounted on a machine tool.

[0026] Figure 2 for Figure 1 Schematic diagram of cross-section.

[0027] Figure 3 for Figure 2 Enlarged view of part A.

[0028] Figure 4 for Figure 2 Enlarged view of part B.

[0029] Figure 5 for Figure 1 A top-down view of the workbench.

[0030] Figure 6 This is a top view schematic diagram of the present invention installed on one side of the lead screw.

[0031] Figure 7 This is a schematic side sectional view of the present invention installed on one side of the lead screw.

[0032] Figure 8 This is a schematic diagram of the displacement detection rings at both ends of the threaded section of the lead screw in this invention.

[0033] Figure 9 This is a schematic cross-sectional view of the displacement detection ring at both ends of the threaded section of the lead screw of the present invention.

[0034] Figure 10 This is a schematic diagram of the clamping sleeves at both ends of the threaded section of the lead screw of the present invention.

[0035] Figure 11 This is a schematic diagram of the measuring rings at both ends of the threaded section of the lead screw in this invention.

[0036] Figure 12 This is a schematic cross-sectional view of the displacement detection ring at the tail end of the lead screw section of the present invention.

[0037] Figure 13 This is a schematic diagram of the end cap of the present invention.

[0038] Figure 14 This is a schematic diagram of the capping device of the present invention.

[0039] Figure 15 This is a schematic diagram of the assembly base of the present invention.

[0040] Figure 16 This is a schematic diagram of the locking sleeve of the present invention.

[0041] Figure 17 This is a schematic diagram of the rod connector of the present invention.

[0042] Figure 18 This is a schematic diagram of the cylindrical expansion sleeve of the present invention.

[0043] Figure 19This is a schematic diagram of the conical expansion sleeve of the present invention.

[0044] In the diagram: 1. Machine bed; 2. Motor mount; 3. Lead screw mount; 4. Linear guide assembly; 5. Drive motor; 6. Interface; 7. Displacement detection ring; 8. Displacement sensor; 9. Lead screw; 10. Clamping sleeve; 11. Measuring ring; 12. Adjusting screw; 13. Spherical washer; 14. Disc spring; 15. Arc end; 16. Tapered hole; 17. Detection bracket; 18. Support rod; 19. Combination base; 20. 21. Base; 22. Slide rail; 23. Slider; 24. Base body; 25. Cylindrical expansion sleeve; 26. Conical expansion sleeve; 27. Tensioning screw; 28. Opening groove; 29. ​​Spacer; 30. Bearing; 31. Pressure cap; 32. Locking nut; 33. End cap; 34. Sealing cap; 35. Cavity; 36. Displacement opening; 37. Notch; 38. Worktable; 39. Connector; 40. Rod joint; 51. Locking sleeve. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Example 1: This example provides a lead screw thermal elongation detection device, which is used for thermal elongation detection of lead screw 9 in a hollow cooling lead screw feed system (it can also be used for thermal elongation detection of other lead screws). For example... Figure 1-7As shown, the hollow cooling screw feed system is installed on the machine tool bed 1, including 9 sets of ball screws, a motor base 2, a screw seat 3, a linear guide assembly 4, and a drive motor 5. The machine tool bed 1 is generally placed on the mounting ground. The 9 sets of ball screws are mounted on the machine tool bed 1. One end of the ball screw 9 is equipped with the motor base 2, and the other end with the screw seat 3. The motor base 2 and the screw seat 3 are fixed to the machine tool bed 1 with screws. The worktable 37 is mounted on the machine tool bed and is generally connected to the screw nut of the ball screw 9 sets. Linear guide assemblies 4 are respectively mounted on both sides of the machine tool bed 1, and the two sides of the worktable 37 are respectively connected to the linear component sliders 22 of the linear guide assembly 4. The drive motor 5 is mounted on the motor base 2. The output end of the drive motor 5 is connected to the screw 9 via a coupling and can drive its rotation. The motor base 2 generally has an interface 6 for connecting cooling pipes, and the interface 6 communicates with the hollow inner cavity of the screw 9.

[0048] (I) The thermal elongation detection device for the lead screw 9 in this embodiment includes a detection bracket 17, which includes a support and a support rod 18. The support rod 18 is arranged parallel to one side of the lead screw 9, and the supports are respectively arranged at both ends of the support rod 18. A slide rail 21 is provided on the machine tool bed 1 at the tail end of the support rod 18, and a slider 22 is slidably connected to the slide rail 21. The support at the head end of the support rod 18 is fixedly arranged on the machine tool bed 1, and the support at the other end is installed on the slider 22.

[0049] The support is made of indium steel, such as Figure 8-19 As shown, the support includes a base 23, a cylindrical expansion sleeve 24, a conical expansion sleeve 25, and a tensioning screw 26. The base 23 is provided with a support hole, and the end of the support rod 18 is inserted into the support hole. The cylindrical expansion sleeve 24 and the conical expansion sleeve 25 are arranged inside the support rod 18 located in the support hole. The cylindrical expansion sleeve 24 is provided with a conical sleeve hole, and the cylindrical expansion sleeve 24 at the conical sleeve hole is provided with multiple open slots 27. The conical expansion sleeve 25 is inserted into the conical sleeve hole, and the tensioning screw 26 passes through the base 23 and is connected to the conical expansion sleeve 25.

[0050] The support rod 18 includes a connector 38, a first hollow carbon fiber rod, and a second hollow carbon fiber rod. The connector 38 includes a rod joint 39 (made of indium tinplate; components directly connected to the support rod 18, such as locking sleeves 40, are also made of indium tinplate) and locking sleeves 40 at both ends. The rod joint 39 has cylindrical heads at both ends that mate with the inner cavities of the first and second hollow carbon fiber rods. The locking sleeves 40 include an upper locking sleeve and a lower locking sleeve. The upper and lower locking sleeves are used with screws to clamp and fix the first and second hollow carbon fiber rods to the rod joint 39. More specifically, after the first and second hollow carbon fiber rods are inserted into the cylindrical heads at both ends of the rod joint 39, the locking sleeves 40 are installed and locked in place. Then, the rod joint 39 and locking sleeves 40 are tightened using screws, effectively connecting the first and second hollow carbon fiber rods. The cylindrical head prevents excessive clamping force from deforming the first and second hollow carbon fiber rods. The presence of machined holes on the hollow carbon fiber rods makes them difficult to work with and prone to failure; therefore, they are not directly bolted for fixation. A common connection method is adhesive bonding, but this suffers from poor interchangeability and weak support strength. Therefore, expansion sleeves are used at both ends of the support rod, with a connecting piece used in the middle.

[0051] The connector 38 is made of indium steel, which reduces the impact of temperature on the measurement. In the structure of the detection bracket 17, the fixed end of the lead screw 9 (motor seat 2 end) is fixed to the machine bed 1 using a support, and the floating end of the lead screw 9 (lead screw seat 3 end) is separated from the machine bed 1 by a slide rail 21 and slider 22 assembly. Since the materials used in the detection bracket 17 are all materials with extremely low coefficients of thermal expansion, the distance from all measurement positions to the fixed end of the lead screw 9 is stable and not easily affected by temperature changes. Therefore, the impact of thermal expansion and contraction of the machine bed 1 on the detection bracket 17 can be effectively reduced.

[0052] (II) The thermal elongation detection device for the lead screw 9 in this embodiment also includes a displacement detection component. The displacement detection component includes a displacement detection ring 7 and a displacement sensor 8. The displacement detection ring 7 is mounted on the lead screw 9, and the displacement sensor 8 is disposed on a support rod 18 on one side of the lead screw 9 and faces the displacement detection ring 7. The lead screw 9 generally includes a head section (for installation in the motor housing 2), a threaded section (for installation of the lead screw nut), and a tail section (for installation in the lead screw seat 3), which are integrally formed. The displacement detection component is respectively disposed at both ends of the threaded section and at the tail end of the tail section. A combination seat 19 is disposed on the support rod 18, and a dial indicator 20 is disposed on the combination seat 19. The displacement sensors 8 of the displacement detection components at both ends of the threaded section and at the tail end of the tail section of the lead screw 9 are respectively mounted on the support rod 18 through the dial indicator 20. The combination seat 19 includes a lower combination seat 19 and an upper combination seat 19, which are connected to the support rod 18 by screws.

[0053] The displacement detection ring 7 includes a clamping sleeve 10, a measuring ring 11, an adjusting screw 12, a spherical washer 13, and a butterfly spring 14. The clamping sleeve 10 is mounted on a lead screw 9, and the measuring ring 11 is mounted on one side of the clamping sleeve 10. The two are connected by an adjusting screw 12, the head of which is equipped with a spherical washer 13. A butterfly spring 14 is mounted on the adjusting screw 12 located between the clamping sleeve 10 and the measuring ring 11. More specifically, countersunk holes for placing the butterfly spring 14 and the spherical washer 13 are respectively provided on both sides of the clamping sleeve 10. The clamping sleeve 10 has an arc end 15 (spherical surface) on the side near the measuring ring 11. The measuring ring 11 has a conical hole 16 (conical surface). The arc end 15 is inserted into the conical hole 16, and the arc surface of the arc end 15 abuts against the inclined surface of the conical hole 16. The two can rotate relative to each other to adjust the tilt angle of the measuring ring 11. Furthermore, adjusting screw 12 tightens spherical washer 13 to tighten measuring ring 11, thereby applying pressure to disc spring 14. The reaction force of disc spring 14 also supports measuring ring 11, keeping the angle of its measured plane stable. The angle of the measured plane (the side facing displacement sensor 8) of measuring ring 11 can be adjusted by adjusting the preload of different adjusting screws 12. The displacement sensor 8 is used to measure the displacement change of the measured plane of measuring ring 11.

[0054] (III) It should be noted that the structure and arrangement of the displacement detection ring 7 located at the tail end of the lead screw 9 are slightly different from the other two locations. The tail end of the lead screw 9 is provided with a lead screw seat 3, and the lead screw seat 3 is provided with a spacer 28 and a bearing 29. The outer end of the bearing 29 is provided with a pressure cap 30, a locking nut 31, an end cap 32, and a sealing cap 33 in sequence. The pressure cap 30 is provided with a cavity 34 to accommodate the displacement detection ring 7. The pressure cap 30 and the end cap 32 are respectively provided with a clearance port 35 and a notch 36 for receiving the displacement sensor 8. The clamping sleeves 10 at both ends of the threaded section of the lead screw 9 are all split structures that are locked with screws, while the clamping sleeve 10 at the lead screw seat 3 is an integral structure, and the size of the measuring ring 11 is also different from the other two locations. The sealing cap 33 has a sealing function and is provided with an interface 6 for connecting the cooling pipe.

[0055] Example 2, based on Example 1, provides a method for installing and adjusting a displacement detection ring 7. In this example, the measured surface of the measuring ring 11 is machined using ultra-precision machining to achieve a flatness within 0.5 μm. When installing the displacement detection ring 7, by adjusting the preload of the adjusting screw 12, the spherical surface of the clamping sleeve 10 and the conical surface of the measuring ring 11 can maintain effective contact and generate relative rotation (tilting rotation, non-circumferential rotation). At the same time, the spherical washer 13 will automatically align itself, eliminating stress between the clamping sleeve 10 and the measuring ring 11. The runout of the measured surface of the measuring ring 11 is measured using a dial indicator, and the preload of the adjusting screw 12 is adjusted to control the surface runout of the measured surface of the measuring ring 11 within 1 μm. Since the lead screw 9 is supported at both ends and has deflection deformation, existing machining and installation methods cannot effectively guarantee that the runout of the measuring surface is within the required error range during the rotation of the lead screw 9. Therefore, this structure and method are proposed. (Achieving a precision of 0.5 μm on a single small plane is easily achievable. With the adjustment structure, the runout of the measured surface can be controlled within a very small error range during the high-speed rotation of the lead screw 9.) By adjusting the preload of the adjusting screw 12, the runout of all the measured surfaces of the measuring rings 11 during one revolution of the lead screw 9 can be adjusted to within 1 μm.

[0056] Example 3 provides a method for measuring and calculating the thermal elongation detection device of the lead screw 9 in the above examples: A reciprocating worktable 37 is moved to bring the feed system to thermal equilibrium. Simultaneously, a displacement sensor 8 measures the displacement of the displacement detection ring 7. The detection values ​​at the beginning and end of the threaded section of the lead screw 9 and at the end of the tail section are L1, L2, and L3, respectively. To eliminate the influence of factors such as friction and elastic deformation of the feed system on the elongation of the lead screw 9, the worktable 37 should be stopped near the motor end during each measurement, with a 0.1 mm overshoot each time, so that the movement is directed towards the lead screw 9 seat. After data acquisition, the lead screw 9 continues to run. This cycle is repeated to measure the thermal elongation of the lead screw 9 from a cold state to a thermal equilibrium state.

[0057] L1 represents the thermal expansion of the head section of lead screw 9 (from the fixed end of the motor to the starting end of the threaded section of lead screw 9), L2 represents the thermal expansion of the head section plus the threaded section of lead screw 9 (from the fixed end of the motor to the ending end of the threaded section of lead screw 9), and L3 represents the thermal expansion of the entire lead screw 9 (from the fixed end of the motor to the floating end of lead screw 9). L2-L1 represents the thermal expansion of the threaded section of lead screw 9, and L3-L2 represents the thermal expansion of the floating end (tail section) of lead screw 9.

[0058] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A device for detecting the thermal elongation of a lead screw, characterized in that: Thermal elongation detection of screw (9) for hollow cooling screw feed system includes displacement detection component, which includes displacement detection ring (7) and displacement sensor (8). The displacement detection ring (7) is installed on screw (9), and the displacement sensor (8) is set on one side of screw (9) and faces displacement detection ring (7). The lead screw (9) includes a head section, a threaded section and a tail section, which are integrally formed. The displacement detection components are respectively set at both ends of the threaded section and the tail end of the tail section to measure the displacement of the lead screw (9) as a whole and each sub-segment during high-speed rotation. The displacement detection ring (7) includes a clamping sleeve (10), a measuring ring (11), an adjusting screw (12), a spherical washer (13), and a butterfly spring (14). The clamping sleeve (10) is mounted on the lead screw (9), and the measuring ring (11) is mounted on one side of the clamping sleeve (10). The two are connected by the adjusting screw (12). The head of the adjusting screw (12) is equipped with a spherical washer (13), and the adjusting screw (12) located between the clamping sleeve (10) and the measuring ring (11) is equipped with a butterfly spring (14). The preload of the adjusting screw (12) is adjusted to control the surface runout of the measuring ring (11) within 1 μm. The preload of different adjusting screws (12) is adjusted to adjust the angle of the measured plane of the measuring ring (11), that is, the side facing the displacement sensor (8). The flatness of the measured plane of the measuring ring (11) reaches within 0.5 μm. The clamping sleeve (10) has an arc end (15) on the side near the measuring ring (11). The measuring ring (11) has a conical hole (16). The arc end (15) is inserted into the conical hole (16). The arc surface of the arc end (15) abuts against the inclined surface of the conical hole (16). The two can rotate relative to each other to adjust the tilt angle of the measuring ring (11). The hollow cooling screw feed system is installed on the machine tool bed (1). The head section and tail section of the screw (9) are respectively provided with a motor seat (2) and a screw seat (3). The motor seat (2) and the screw seat (3) are fixed to the machine tool bed (1) by screws. The motor seat (2) is provided with an interface (6) for connecting the cooling pipe. The interface (6) is connected to the hollow cavity of the screw (9). The screw seat (3) is provided with a spacer (28) and a bearing (29). The outer end of the bearing (29) is provided with a pressure cap (30) and a locking nut (31) in sequence. The end cap (32) and sealing cap (33) are provided; the pressure cap (30) is provided with a cavity (34) for accommodating the displacement detection ring (7), and the pressure cap (30) and the end cap (32) are respectively provided with a relief opening (35) and a notch (36) for receiving the displacement sensor (8); the clamping sleeves (10) at both ends of the threaded section of the lead screw (9) are all split structures with screw locking, and the clamping sleeve (10) at the lead screw seat (3) is an integral structure; the sealing cap (33) has a sealing function and is provided with an interface for connecting the cooling pipe.

2. The lead screw thermal elongation detection device according to claim 1, characterized in that: It also includes a detection bracket (17), which has a thermal expansion coefficient of not more than 1.2 × 10⁻⁶. -6 The material is made of / K; the detection bracket (17) includes a support and a support rod (18), the support rod (18) is provided on one side of the lead screw (9), the support rod (18) is provided with a combination seat (19), the combination seat (19) is provided with a dial indicator (20), the displacement sensors (8) of the displacement detection components at both ends of the threaded section and the tail end of the tail section of the lead screw (9) are respectively installed on the support rod (18) through the dial indicator (20), and the support is provided at both ends of the support rod (18).

3. The lead screw thermal elongation detection device according to claim 2, characterized in that: The tail end of the support rod (18) is provided with a slide rail (21), and a slider (22) is slidably connected on the slide rail (21). The support at one end of the support rod (18) is fixedly set, and the support at the other end is installed on the slider (22).

4. The lead screw thermal elongation detection device according to claim 3, characterized in that: The support includes a base (23), a cylindrical expansion sleeve (24), a conical expansion sleeve (25), and a tensioning screw (26). The base (23) is provided with a support hole. The end of the support rod (18) is inserted into the support hole. The cylindrical expansion sleeve (24) and the conical expansion sleeve (25) are provided in the support rod (18) located in the support hole. The cylindrical expansion sleeve (24) is provided with a conical sleeve hole. The cylindrical expansion sleeve (24) at the conical sleeve hole is provided with multiple opening slots (27). The conical expansion sleeve (25) is inserted into the conical sleeve hole. The tensioning screw (26) passes through the base (23) and is connected to the conical expansion sleeve (25).

5. The detection method of the lead screw thermal elongation detection device according to any one of claims 1-4, characterized in that: A worktable (37) is set on the lead screw (9), and the worktable (37) is moved back and forth to make the lead screw (9) reach a thermal equilibrium state. The displacement sensors (8) at both ends of the thread section and the tail end of the lead screw (9) are used to measure the displacement of the corresponding displacement detection ring (7). The values ​​are L1, L2 and L3 in sequence. L1 is the thermal elongation of the head section of the lead screw (9), L2 is the thermal elongation of the thread section and the head section of the lead screw (9), L3 is the thermal elongation of the entire lead screw (9), L2-L1 is the thermal elongation of the thread section of the lead screw (9), and L3-L2 is the thermal elongation of the tail section of the lead screw (9).

6. The detection method of the lead screw thermal elongation detection device according to claim 5, characterized in that: When measuring the thermal elongation of the lead screw (9) from a cold state to a thermal equilibrium state, the worktable (37) is moved from the motor seat (2) with an overtravel of 0.1 mm each time, so that the movement is directed toward the lead screw seat (3). After data collection, the lead screw (9) is continued to run. This cycle is repeated to measure the thermal elongation of the lead screw (9) from a cold state to a thermal equilibrium state.

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