Device and method for dynamically measuring stroke error of inner raceway of nut

Abstract

The invention discloses a nut inner raceway stroke error dynamic measurement device and method. The device comprises a supporting part used for bearing other parts of the device; the clamping part is used for clamping and fixing the nut to be detected; the transmission part is used for transmitting power to drive the nut to rotate; the measuring part is used for measuring the stroke error of the to-be-measured nut; and the axial moving part is used for carrying the measuring part to move axially. The circular grating is mounted at the tail end of the spindle and serves as an angle reference for measuring rotation of the nut; the optical fiber laser interference ruler is installed on the supporting base on the left side of the lathe bed, the linear displacement of the workbench can be stably measured, and an accurate length reference is provided for a system. The measuring device has the characteristics of small size, high precision, high automation degree, dynamic measurement and the like, and is suitable for detecting the stroke error of the inner raceway of the nut.

Description

Technical Field

[0001] This invention belongs to the field of ball screw pair testing technology, and in particular, a dynamic measurement device and method for the stroke error of the inner raceway of a nut. Background Technology

[0002] A ball screw assembly is a rolling functional component that converts rotary motion into linear motion. Due to its advantages such as high precision, high efficiency, high rigidity, and high load-bearing capacity, it is widely used in industrial fields such as CNC machine tools, oil drilling, and precision instruments. Common ball screw assemblies use a servo motor to drive the ball screw rotation, which in turn drives the ball nut to move linearly axially; this is also called forward drive, and such ball screw assemblies are called forward ball screw assemblies. However, forward ball screw assemblies are relatively large in size, making it difficult to coordinate the load-bearing capacity and size parameters of the overall component in miniaturized and lightweight applications. Reverse ball screw assemblies, on the other hand, use a motor to drive the nut rotation, which in turn drives the screw to move linearly axially. Therefore, the effective length of the nut's thread must be greater than the effective length of the screw's thread. In this case, the travel error of the nut's internal raceway directly affects the transmission accuracy and performance of the ball screw assembly.

[0003] Currently, the system for detecting the travel error of lead screws is relatively complete, but there is no dedicated equipment to detect the travel error of the inner raceway of the nut. Therefore, it is particularly important to develop a device that can accurately, efficiently and stably detect the travel error of the inner raceway of the nut. Summary of the Invention

[0004] The purpose of this invention is to address the defects or deficiencies of the existing technology by providing a dynamic measurement device and method for the inner raceway stroke error of a nut.

[0005] The technical solution to achieve the purpose of this invention is: a dynamic measuring device for the inner raceway stroke error of a nut, the device comprising a support component, a transmission component, a clamping component, a measuring component, an axial movement component, and supporting auxiliary components;

[0006] The supporting component is used to support other components of the measuring device;

[0007] The transmission component is used to transmit power to achieve the rotation of the nut under test;

[0008] The clamping component is used to clamp and fix the nut to be tested;

[0009] The measuring component is used to measure the travel error of the inner raceway of the nut;

[0010] The axial moving component and its supporting auxiliary components are used to carry the measuring component to move axially, with the axial direction perpendicular to the reference plane of the nut to be measured.

[0011] Furthermore, the supporting components include a marble bed, a laser ruler support, and a bearing support; both the laser ruler support and the bearing support are mounted on the upper surface of the marble bed and are coaxially arranged; the working surface of the laser ruler support is parallel to the upper surface of the marble bed, and the laser ruler support is used to mount a fiber laser ruler.

[0012] Furthermore, the transmission components include a servo motor, a linear motor, a flat pulley, a flat belt, and a spindle; the servo motor is fixedly mounted on the machine bed via a motor adapter plate; there are two flat pulleys, one of which is coaxially fixed to the output shaft end of the servo motor, and the other is coaxially fixed to the leftmost end of the spindle. The two flat pulleys are connected by a flat belt drive to realize the power transmission between the servo motor and the spindle; the linear motor is mounted on the machine bed and is used to drive the air-bearing worktable to perform linear reciprocating motion; the bearing support seat, as the core radial support component of the spindle, is equipped with matching bearing end caps, including a left bearing end cap and a right bearing end cap fixed to the left and right ends of the bearing support seat, for sealing protection and axial auxiliary limiting of the bearing, and to complete the stable support of the spindle in conjunction with the bearing support seat; the inner hole of the bearing support seat is interference-fitted with the outer ring of the angular contact ball bearing on the spindle to achieve radial positioning of the spindle; wherein, left and right refer to the left and right sides along the length direction of the marble machine bed.

[0013] Furthermore, the clamping component includes a four-jaw chuck, a workpiece clamping fixture, and a rotary clamping cylinder mounted on the workpiece clamping fixture; the four-jaw chuck is coaxially mounted at the rightmost end of the spindle, and the coaxiality of the clamped workpiece and the spindle is ensured by adjusting the radial extension and retraction of the four jaws in the four-jaw chuck; the workpiece clamping fixture is adapted to the nut to be tested, and the rotary clamping cylinders are symmetrically arranged on it, and the two work together to achieve axial fixation of the nut to be tested.

[0014] Furthermore, the axial moving component and its supporting auxiliary components include an air-bearing worktable, a hydraulic buffer, a buffer support, a dual-axis linear guide, a limiting slider, a cable chain, a cable chain adapter plate, and a reference plate. The air-bearing worktable is mounted on the air-bearing guide on the marble bed and is fixedly connected to the mover of the linear motor. The linear motor drives the air-bearing worktable to perform linear reciprocating motion. The buffer support is fixedly mounted on the marble bed, and the hydraulic buffer is mounted on the buffer support. The dual-axis linear guide is mounted on one side of the air-bearing guide, and the limiting slider is assembled on the dual-axis linear guide and linked with the air-bearing worktable to limit the travel of the air-bearing worktable. The cable chain adapter plate is fixedly mounted on one side of the air-bearing worktable, and the cable chain is fixedly connected to the cable chain adapter plate to store pipelines and move synchronously with the air-bearing worktable. The reference plate is mounted on the left side of the air-bearing worktable and coincides with the left end face of the air-bearing worktable, serving as a reference surface for dial indicator measurements.

[0015] Furthermore, the measuring components include a circular grating, a reading device, a circular grating positioning sleeve, a tightening nut, a reading head bracket, a fiber laser ruler, a reflector, a measuring bracket, a floating sleeve, a handle, a push rod, a measuring rod, a return spring, a locking sleeve, a measuring head, a torsion spring, and a torsion spring pressure block;

[0016] The circular grating is mounted on the circular grating positioning sleeve and serves as an angular reference for measuring the rotation of the nut. The circular grating positioning sleeve is mounted on the main shaft and near its left end. A stop device is fitted on the circular grating positioning sleeve to limit its radial movement. The tightening nut is screwed onto the left side of the circular grating positioning sleeve via threads on the main shaft to limit its axial movement. The reading head bracket is fixed to the left end cover of the bearing, and the reading head is mounted on the reading head bracket to read the angle signal of the circular grating. The fiber laser ruler is mounted on the laser ruler support to stabilize the linear displacement of the air-bearing worktable and provide a precise length reference for the device. The reflector is mounted on the left end face of the measuring rod and works with the fiber laser ruler to achieve displacement detection. The measuring bracket is mounted on the air-bearing worktable and maintains coaxiality with the main shaft. The floating sleeve uses a splined shaft and splined nut to form a splined shape. The device features a keyed joint structure and is coaxially mounted with the measuring bracket. The end flange of the splined nut is fixed to the left side of the measuring bracket. The measuring rod is installed inside the splined shaft with a tight fit and is axially fixed by a locking sleeve. Through the guiding action of the splined joint, the splined shaft can drive the measuring rod to move smoothly axially back and forth along the axis of the measuring bracket, while restricting the circumferential rotation of the splined shaft relative to the measuring bracket. The push rod is installed inside the measuring rod and drives the measuring rod to move axially by the threaded feed action of the handle installed on the right side of the measuring bracket. The return spring is fixed by inserting a hinge into the slot of the push rod to achieve self-reset after the push rod moves forward axially. The probe is installed in the square hole at the left end of the measuring rod. The torsion spring is supported between the probe and the measuring rod, with the fixed side arm of the torsion spring abutting against the arc-shaped groove at the left end of the measuring rod, and the force-applying side arm hooked into the slot of the probe carrier. The torsion spring pressure block fits against the end face of the torsion spring to prevent axial movement of the torsion spring.

[0017] Furthermore, the emitting end face of the fiber laser ruler and the reflecting end face of the reflector are on the same straight line, and the main shaft is designed as a hollow structure. The measuring light emitted by the fiber laser ruler passes through the hollow main shaft along the axial direction of the nut being measured, so that the reference line of the measuring light coincides with the measuring reference axis of the inner raceway of the nut being measured, and no Abbe error is generated.

[0018] Furthermore, the connection between the push rod and the probe is provided with a wedge-shaped clamping structure. The wedge-shaped clamping structure is composed of an inclined groove opened inside the probe and a conical head of the push rod. The inclination angle of the inclined groove matches the taper of the conical head. The radial positioning of the probe is achieved by the tangential fit between the conical head and the inclined groove. At the same time, in conjunction with the elastic force of the torsion spring, the probe maintains a stable posture during the measurement process without radial movement.

[0019] Furthermore, the screw handle and the spline shaft are fitted with a fine-pitch ordinary thread to achieve helical feed. The lead accuracy of the fine-pitch thread is not lower than IT5 grade, and the outer circumference of the screw handle is provided with an anti-slip knurled structure. By rotating the screw handle, the push rod is driven to move axially, and the conical head of the push rod makes a wedge-shaped feed along the inclined groove, pressing the probe against the preset measurement position of the inner raceway of the nut. The feed amount is precisely controlled by the rotation angle of the screw handle to adapt to the measurement position adjustment requirements of the inner raceway of nuts of different specifications.

[0020] Furthermore, the torsion spring pressure block is connected to the end of the measuring rod via an internal thread, and rotating the torsion spring pressure block can adjust its contact pressure with the end face of the torsion spring.

[0021] Compared with the prior art, the significant advantages of this invention are:

[0022] (1) The measuring device of the present invention has the characteristics of small size, high precision, high degree of automation and dynamic measurement, and is suitable for the detection of inner raceway of nuts of various types and different specifications, and has strong versatility.

[0023] (2) The measuring device of the present invention has good adaptability and adjustment capability. It only requires simple replacement of the measuring rod and measuring head to measure the nut stroke error in the mean diameter range of 14mm-85mm.

[0024] (3) By optimizing the measurement optical path and structural design, the present invention sets the main shaft as a hollow structure, so that the measurement light reference line of the fiber laser ruler is precisely coincided with the measurement reference axis of the inner raceway of the nut being measured, thereby avoiding the generation of Abbe error from the root and significantly improving the overall accuracy and data reliability of stroke error measurement.

[0025] (4) The device transmission system adopts a servo motor + flat belt drive to drive the spindle to rotate. The flat belt drive has the advantages of smooth operation, low noise, and buffering and vibration absorption, which can avoid the impact vibration caused by rigid transmission. It is combined with a linear motor to drive the air-floating worktable to move, so as to realize the precise linkage between the rotation of the nut and the axial movement of the measuring component, and ensure that the probe completely covers the entire stroke of the inner raceway.

[0026] (5) The clamping component adopts a four-jaw chuck in conjunction with a symmetrically arranged rotary clamping cylinder. By adjusting the radial extension of the jaws, the coaxiality of the tooling and the spindle is ensured. At the same time, the cylinder is used to fix the nut axially. The clamping and positioning accuracy is high and the stability is strong, which effectively prevents the nut from radially shifting or axially moving during the measurement process.

[0027] (6) The measuring component adopts a precision wedge clamping structure with an adjustable torsion spring assembly. The probe is made of precision ceramic material and the contact end is designed with a rounded transition structure. The elastic force of the torsion spring ensures that the probe and the inner raceway are always stably attached, while avoiding scratches and damage to the raceway surface caused by rigid contact, thus taking into account both measurement stability and workpiece protection.

[0028] (7) The floating sleeve adopts a spline pair structure with spline shaft and spline nut, which can drive the measuring rod to move smoothly along the axis of the measuring bracket in the axial direction, while restricting circumferential rotation, ensuring that the movement trajectory of the measuring head is strictly parallel to the inner raceway axis of the nut, and effectively eliminating the measurement error caused by the deflection of the measuring rod.

[0029] (8) The screw handle and the floating sleeve spline shaft are fitted with fine thread with a lead accuracy of not less than IT5. The outer circumference of the screw handle is provided with an anti-slip knurled structure, which can not only accurately control the feed amount of the probe by rotating the angle, but also facilitate manual adjustment by the operator, adapting to the measurement position requirements of the inner raceway of different specifications of nuts, with high adjustment accuracy and convenient operation.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is an isometric view of the overall assembly of the measuring device in one embodiment.

[0032] Figure 2 This is a top view of the measuring device in one embodiment.

[0033] Figure 3 This is a right view of the measuring device in one embodiment.

[0034] Figure 4 This is a cross-sectional view of the measuring device spindle assembly in one embodiment.

[0035] Figure 5 This is a schematic diagram of the exploded structure of the measuring component of the measuring device in one embodiment.

[0036] Figure 6 This is a schematic diagram showing the initial contact between the probe and the inner raceway of the nut in one embodiment.

[0037] Figure 7 This is a schematic diagram illustrating stable contact between the probe and the inner raceway of the nut in one embodiment.

[0038] The meanings represented by the numbers in the diagram are as follows:

[0039] 1-Marble bed, 2-Servo motor, 3-Laser ruler support, 4-Fiber laser ruler, 5-Flat belt, 6-Bearing left end cover, 7-Bearing support, 8-Bearing right end cover, 9-Four-jaw chuck, 10-Workpiece clamping fixture, 11-Rotary clamping cylinder, 12-Base plate, 13-Air-floating worktable, 14-Buffer support, 15-Hydraulic buffer, 16-Drag chain adapter plate, 17-Drag chain, 18-Linear motor, 19-Dual-axis linear guide, 20-Limit slider, 21-Motor adapter plate, 22-Reading, 23- - Reading head bracket, 24- Flat pulley, 25- Tightening nut, 26- Circular grating, 27- Circular grating positioning sleeve, 28- Locking nut, 29- Angular contact ball bearing, 30- Sleeve, 31- Outer spacer, 32- Inner spacer, 33- Main shaft, 34- Measured nut, 35- Reflector, 36- Torsion spring pressure block, 37- Torsion spring, 38- Probe, 39- Locking sleeve, 40- Measuring rod, 41- Push rod, 42- Return spring, 43- Floating sleeve spline shaft, 44- Floating sleeve spline nut, 45- Measuring bracket, 46- Handle Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0043] In one embodiment, combined Figures 1 to 7A dynamic measuring device for the inner raceway stroke error of a nut is provided. The device includes a support component, a transmission component, a clamping component, a measuring component, an axial movement component, and supporting auxiliary components.

[0044] The supporting component is used to support other components of the measuring device;

[0045] The transmission component is used to transmit power to achieve the rotation of the nut under test;

[0046] The clamping component is used to clamp and fix the nut to be tested;

[0047] The measuring component is used to measure the travel error of the inner raceway of the nut;

[0048] The axial moving component and its supporting auxiliary components are used to carry the measuring component to move axially, with the axial direction perpendicular to the reference plane of the nut to be measured.

[0049] Furthermore, in one embodiment, the supporting component includes a marble bed 1, a laser ruler support 3, and a bearing support 7; the laser ruler support 3 and the bearing support 7 are both mounted on the upper surface of the marble bed 1 and are coaxially arranged; the working surface of the laser ruler support 3 is parallel to the upper surface of the marble bed 1, and the laser ruler support 3 is used to mount a fiber laser ruler 4.

[0050] Further, in one embodiment, the transmission components include a servo motor 2, a linear motor 18, a flat pulley 24, a flat belt 5, and a spindle 33; the servo motor 2 is fixedly mounted on the bed 1 via a motor adapter plate 21; two flat pulleys 24 are provided, one of which is coaxially fixed to the output shaft end of the servo motor 2, and the other is coaxially fixed to the leftmost end of the spindle 33, and the two flat pulleys 24 are connected by the flat belt 5 to realize the power transmission between the servo motor 2 and the spindle 33; the linear motor 18 is mounted on the bed 1 and is used to drive... The air-floating worktable 13 performs linear reciprocating motion; the bearing support seat 7, as the core radial support component of the main spindle 33, is equipped with matching bearing end caps, including a left bearing end cap 6 and a right bearing end cap 8 fixed to the left and right ends of the bearing support seat 7, used to achieve bearing sealing protection and axial auxiliary limiting, and to cooperate with the bearing support seat 7 to complete the stable support of the main spindle 33; the inner hole of the bearing support seat 7 is interference-fitted with the outer ring of the angular contact ball bearing 29 on the main spindle 33 to achieve radial positioning of the main spindle 33; wherein, left and right refer to the left and right sides along the length direction of the marble bed 1.

[0051] Here, the support structure of the main shaft 33 is divided into a front support and a rear support. The front support is a fixed support, preferably using a precision triple angular contact ball bearing 29. The right side of the triple angular contact ball bearing 29 is axially positioned by the shoulder of the main shaft 33. Between the two bearings and the third bearing on the front side, there are inner spacers 32 and outer spacers 31 of the same width to ensure uniform preload clearance between the bearings. The inner ring of the triple angular contact ball bearing 29 is interference-fitted with the main shaft 33, and the outer ring is also interference-fitted with the bearing housing 7. At the same time, the axial fixation of the outer ring of the bearing is achieved by the right end cover 8 of the bearing, realizing the rigid positioning of the front support. The rear support is a floating support, preferably using a pair of back-to-back angular contact ball bearings 29. The inner ring of this pair of bearings is interference-fitted with the main shaft 33, and the outer ring is interference-fitted with the bearing housing 7 to ensure the connection stability of the rear support. Between the front support and the rear support, a sleeve 30 supports the inner rings of the bearings on both sides to maintain the coaxiality of the front and rear supports. The bearing on the outer side of the rear support is positioned by an outer ring end cap and locked by an inner ring nut. The outer ring of the bearing is fixed by the left end cap 6 of the bearing, and the axial movement of its inner ring is restricted by the locking nut 28 tightened on the main shaft 33 to prevent the bearing from moving during the rotation of the main shaft 33.

[0052] Preferably, the bearing support 7 is detachably and fixedly connected to a pre-set mounting hole on the marble bed 1 via, but not limited to, bolt assemblies.

[0053] Preferably, the linear motor 18 is installed in the middle groove of the air-bearing guide rail on the right side of the bed.

[0054] Furthermore, in one embodiment, the clamping component includes a four-jaw chuck 9, a workpiece clamping fixture 10, and a rotary clamping cylinder 11 disposed on the workpiece clamping fixture 10; the four-jaw chuck 9 is coaxially mounted at the rightmost end of the spindle 33, and the coaxiality of the clamped workpiece and the spindle 33 is ensured by adjusting the radial extension and retraction of the four jaws in the four-jaw chuck 9; the workpiece clamping fixture 10 is adapted to the nut 34 to be tested, and the rotary clamping cylinder 11 is symmetrically arranged on it, and the two cooperate to achieve axial fixation of the nut 34 to be tested.

[0055] Here, after the nut 34 to be tested is placed on the positioning reference surface of the workpiece clamping fixture 10, the piston rod of the rotating clamping cylinder 11 is activated, and the end face of the nut 34 to be tested is pressed to achieve reliable axial fixation of the nut 34 to be tested, so as to prevent axial movement during the measurement process.

[0056] Further, in one embodiment, the axial moving component and its supporting auxiliary components include an air-floating worktable 13, a hydraulic buffer 15, a buffer support 14, a dual-axis linear guide rail 19, a limit slider 20, a cable chain 17, a cable chain adapter plate 16, and a reference plate 12; the air-floating worktable 13 is mounted on the air-floating guide rail on the marble bed 1 and is fixedly connected to the mover of the linear motor 18, the linear motor 18 being used to drive the air-floating worktable 13 to perform linear reciprocating motion; the buffer support 14 is fixedly mounted on the marble bed 1, and the hydraulic buffer 15 is mounted on... The buffer support 14 is mounted on the buffer support 14; the dual-axis linear guide 19 is mounted on one side of the air-bearing guide rail, and the limiting slider 20 is mounted on the dual-axis linear guide 19 and linked with the air-bearing worktable 13 to limit the travel of the air-bearing worktable 13; the drag chain adapter plate 16 is fixedly mounted on one side of the air-bearing worktable 13, and the drag chain 17 is fixedly connected to the drag chain adapter plate 16 to store pipelines and move synchronously with the air-bearing worktable 13; the reference plate 12 is mounted on the left side of the air-bearing worktable 13 and coincides with the left end face of the air-bearing worktable 13, serving as the reference surface for dial gauge measurement.

[0057] Preferably, the buffer support 14 is fixedly installed in the middle groove of the marble bed 1 to buffer the impact force when the air-floating worktable 13 moves to the extreme position, so as to avoid rigid collision damage to the components.

[0058] Here, the various parts are fixedly connected by, but not limited to, bolts.

[0059] Furthermore, the measuring components include a circular grating 26, a reading 22, a circular grating positioning sleeve 27, a tightening nut 25, a reading head bracket 23, a fiber laser ruler 4, a reflector 35, a measuring bracket 45, a floating sleeve 43, a handle 46, a push rod 41, a measuring rod 40, a return spring 42, a locking sleeve 39, a measuring head 38, a torsion spring 37, and a torsion spring pressure block 36;

[0060] The circular grating 26 is mounted on the circular grating positioning sleeve 27 and serves as an angular reference for measuring the rotation of the measuring nut 34. The circular grating positioning sleeve 27 is mounted on the main shaft 33 and near its left end. A stop device is fitted on the circular grating positioning sleeve 27 to limit its radial movement. The tightening nut 25 is screwed onto the left side of the circular grating positioning sleeve 27 via threads on the main shaft 33, relying on thread preload to limit the axial movement of the circular grating positioning sleeve 27. The reading head 22 is mounted on the reading head bracket 23, which is fixed to... On the left end cover 6 of the bearing, the relative position between the reading head 22 and the circular grating 26 is kept constant. The reading head 22 is used to read the angle signal of the circular grating 26. The fiber laser ruler 4 is mounted on the laser ruler support 3 to stabilize the linear displacement of the air-bearing worktable 13 and provide a precise length reference for the device. The reflector 35 is mounted on the left end face of the measuring rod 40 and cooperates with the fiber laser ruler 4 to realize displacement detection. The measuring bracket 45 is mounted on the air-bearing worktable 13 and maintains coaxiality with the main shaft 33. The floating sleeve adopts a splined shaft 43 and a splined nut 4. 4. A splined pair structure is formed by the splined nut 44 and coaxially mounted with the measuring bracket 45. The end flange of the splined nut 44 is fixedly connected to the left side of the measuring bracket 45. The measuring rod 40 is installed inside the splined shaft 43 with a tight fit and is axially fixed by the locking sleeve 39. Through the guiding effect of the splined pair, the splined shaft 43 can drive the measuring rod 40 to make a smooth axial reciprocating movement along the axis of the measuring bracket 45, while restricting the circumferential rotation of the splined shaft 43 relative to the measuring bracket 45. The push rod 41 is installed inside the measuring rod 40 and is connected by a handle 46 installed on the right side of the measuring bracket 45. The threaded feed action drives the probe 40 to move axially; the return spring 42 is fixed by being inserted into the slot of the push rod 41 through a hinge, and is used to realize the self-reset of the push rod 41 after it moves forward axially; the probe 38 is installed in the square hole at the left end of the probe 40; the torsion spring 37 is supported between the probe 38 and the probe 40, and the fixed side arm of the torsion spring 37 is in contact with the arc-shaped groove opened at the left end of the probe 40, and the force-applying side arm is hooked into the slot of the probe 38 carrier, providing elastic preload to the probe 38; the torsion spring pressure block 36 is in contact with the end face of the torsion spring 37 to prevent the torsion spring 37 from moving axially.

[0061] Here, radial positioning is achieved by tightening the outer circumferential surface of the spindle 33 with a stop screw.

[0062] Preferably, in some embodiments, the fiber laser ruler 4 and the reading head 22 are connected to an external PC via cables for recording, storing, and calculating the measured data.

[0063] Preferably, in some embodiments, to improve measurement accuracy, the emitting end face of the fiber laser ruler 4 and the reflecting end face of the reflector 35 are on the same straight line, the main shaft 33 is set as a hollow structure, and the measuring light emitted by the fiber laser ruler 4 passes through the hollow main shaft 33 along the axial direction of the nut 34 being measured, so that the reference line of the measuring light coincides with the measuring reference axis of the inner raceway of the nut 34 being measured, without Abbe error, and ensuring the accuracy of linear displacement measurement.

[0064] Preferably, in some embodiments, the end flange of the spline nut 44 is fastened to the measuring bracket 45 by circumferentially evenly arranged internal hexagonal head screws. Through the guiding effect of the spline pair, the spline shaft can drive the measuring rod 40 to make a smooth axial reciprocating movement along the axial direction of the measuring bracket 45, while restricting the circumferential rotation of the spline shaft relative to the measuring bracket 45.

[0065] Preferably, in some embodiments, the probe 38 is made of precision ceramic material, the contact end of the probe 38 with the inner raceway is set as an arc transition structure, the torsion spring 37 is made of high-strength spring steel, and its preload can be achieved by fine adjustment of the axial position of the torsion spring pressure block 36, so as to ensure that the probe 38 always elastically fits the inner raceway of the nut, avoiding rigid contact from causing damage to the raceway surface and measurement errors.

[0066] Here, the probe 38 is spherical and replaceable, matching the type and size of the nut 34 to be tested.

[0067] Preferably, in some embodiments, the connection between the push rod 41 and the probe 38 is provided with a wedge-shaped clamping structure. The wedge-shaped clamping structure is composed of an inclined groove opened in the probe 38 and a conical head of the push rod 41. The inclination angle of the inclined groove matches the taper of the conical head. The radial positioning of the probe 38 is achieved by the tangential contact between the conical head and the inclined groove. At the same time, in conjunction with the elastic force of the torsion spring 37, the probe 38 maintains a stable posture during the measurement process without radial movement, thus ensuring measurement accuracy.

[0068] Preferably, in some embodiments, the shank 46 and the spline shaft 43 are fitted with, but not limited to, fine-pitch ordinary threads to achieve helical feed. The lead accuracy of the fine-pitch thread is not lower than IT5 grade, and the outer circumference of the shank 46 is provided with an anti-slip knurled structure. By rotating the shank 46, the push rod 41 is driven to move axially, and the conical head of the push rod 41 makes a wedge-shaped feed along the inclined groove, pressing the probe 38 to the preset measurement position of the inner raceway of the nut. The feed amount is precisely controlled by the rotation angle of the shank 46 to adapt to the measurement position adjustment requirements of the inner raceway of nuts of different specifications.

[0069] Preferably, in some embodiments, the torsion spring pressure block 36 is threaded to the end of the measuring rod 40 via an internal thread. Rotating the torsion spring pressure block 36 can adjust the contact pressure between it and the end face of the torsion spring 37. This effectively prevents the torsion spring 37 from moving axially during measurement and avoids excessive pressure that could cause deformation of the torsion spring 37, ensuring a stable output of the elastic force of the torsion spring 37.

[0070] Here, when measuring the travel error of the inner raceway of the nut, the probe 38 should be aligned with... Figure 7 The nut's inner raceway is shown to maintain stable contact. To prevent the probe 38 from interfering with the nut raceway during measurement... Figure 6 The measurement error caused by the contact state shown is addressed by incorporating an adaptive fine-tuning system consisting of a torsion spring 37, a torsion spring pressure block 36, a push rod 41, and a return spring 42 into the measuring device of the present invention. The torsional elastic force generated by the stretching of the torsion spring 37 can make the probe 38 adaptively slide to stable contact with the inner raceway of the nut.

[0071] In one embodiment, a measurement method based on the dynamic measurement device for the inner raceway stroke error of the nut is provided. The measurement principle is as follows: the circular grating 26 measures the rotation angle θ of the nut 34 in real time, and the laser interference ruler 4 and the reflector 35 cooperate to measure the actual linear displacement S; by synchronously acquiring θ and S, the theoretical displacement S is calculated. 理论 =Lead P×θ, and compared with the measured value S 实际 By comparison, the travel error ΔS = S 实际 -S 理论 .

[0072] Furthermore, in one embodiment, the method includes the following steps:

[0073] Step 1: Install the workpiece clamping fixture 10 that is compatible with the nut 34 to be tested onto the four-jaw chuck 9, adjust the radial extension of the jaws, and check the coaxiality of the fixture with a dial indicator to ensure that its coaxiality error with the spindle 33 is ≤ the preset threshold.

[0074] Preferably, the preset threshold is 0.002 mm.

[0075] Step 2: Place the nut 34 to be tested in the workpiece clamping fixture 10, start the rotary clamping cylinder 11, and fix the nut 34 to be tested axially through the force of the symmetrical cylinder to prevent axial movement during measurement.

[0076] Step 3: Rotate the handle 46 and use the IT5 grade fine thread between the handle 46 and the floating sleeve spline shaft 43 to achieve helical feed, drive the push rod 41 to move axially, so that the probe 38 is pressed against the preset measurement position of the inner raceway of the nut by the wedge feed.

[0077] Step 4: Start the fiber laser ruler 4 and calibrate the coaxiality of its transmitter and reflector 35 to ensure that the measurement light is transmitted along the axis of the hollow main shaft 33 and nut 34 to eliminate Abbe error; at the same time, read the angle signal of the circular grating 26 through the reading head 22 to complete the angle reference calibration and ensure that the signal transmission is stable and rotates synchronously with the main shaft.

[0078] Step 5: Start servo motor 2 and linear motor 18. Servo motor 2 drives the flat pulley 24 to rotate, which in turn drives the spindle 33 and the clamped nut 34 to rotate at a uniform speed via the flat belt 5. Set the rotation speed of spindle 33 to 50-200 r / min, adjusting it according to the nut specifications and measurement accuracy requirements. The motion parameters of linear motor 18 are set through the control system, driving the air-bearing table 13 to reciprocate linearly along the air-bearing guide rail. Simultaneously, this drives the measuring component to move axially perpendicular to the nut's reference plane. The axial movement speed is set to match the spindle rotation speed to ensure that the probe 38 can completely cover the entire travel of the nut's inner raceway. At the same time, the hydraulic buffer 15 and limit slider 20 are activated, setting the table's travel limit.

[0079] Step 6: The fiber laser ruler 4 collects the displacement signal fed back by the reflector 35 in real time, accurately measures the axial displacement data of the worktable and measuring components, the circular grating 26 records the angle data of the nut rotation simultaneously, and the reading head 22 converts the angle signal into an electrical signal and transmits it to the control system. Together with the axial displacement data collected by the fiber laser ruler 4, the synchronous acquisition and associated storage of axial displacement and rotation angle are realized.

[0080] Step 7: After measurement, turn off the motor and all measuring components; rotate the handle 46 in the opposite direction to reset the push rod 41. The push rod 41 returns to its initial position under the action of the return spring 42, and the probe 38 disengages from the inner raceway of the nut. Close the rotary clamping cylinder 11, release the four-jaw chuck 9, remove the nut 34 to be measured and the workpiece clamping fixture 10, and clean all contact surfaces to avoid residual impurities affecting subsequent measurements.

[0081] Step 8: Repeat steps 1 to 7 above to collect multiple sets of travel error data for subsequent error analysis and calibration, ensuring the repeatability and accuracy of the measurement results.

[0082] The measuring device of this invention has the advantages of compact structure, high measurement accuracy, fast detection speed, and dynamic measurement. It can be adapted to the internal raceway detection scenarios of various types and specifications of nuts, and has strong versatility. Secondly, the measuring device has good adaptability and adjustment capabilities. Nuts with different ball diameters can be measured by simply changing the measuring rod and measuring head. In addition, the measuring device provides a new design idea for measuring the stroke error of the internal raceway of nuts, which is of great significance for improving the performance of ball screw pairs.

[0083] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention without departing from its spirit and scope should be included within the protection scope of the present invention.

Claims

1. A dynamic measuring device for the stroke error of the inner raceway of a nut, characterized in that, The device includes a support component, a transmission component, a clamping component, a measuring component, an axial movement component, and supporting auxiliary components; The supporting component is used to support other components of the measuring device; The transmission component is used to transmit power to achieve the rotation of the nut under test; The clamping component is used to clamp and fix the nut to be tested; The measuring component is used to measure the travel error of the inner raceway of the nut; The axial moving component and its supporting auxiliary components are used to carry the measuring component to move axially, with the axial direction perpendicular to the reference plane of the nut to be measured.

2. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 1, characterized in that, The supporting components include a marble bed (1), a laser ruler support (3) and a bearing support (7); the laser ruler support (3) and the bearing support (7) are both installed on the upper surface of the marble bed (1) and are coaxially arranged; the working surface of the laser ruler support (3) is parallel to the upper surface of the marble bed (1), and the laser ruler support (3) is used to install a fiber laser ruler (4).

3. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 2, characterized in that, The transmission components include a servo motor (2), a linear motor (18), a flat pulley (24), a flat belt (5), and a main spindle (33); the servo motor (2) is fixedly mounted on the bed (1) via a motor adapter plate (21); there are two flat pulleys (24), one of which is coaxially fixed to the output shaft end of the servo motor (2), and the other is coaxially fixed to the leftmost end of the main spindle (33). The two flat pulleys (24) are connected by a flat belt (5) to realize the power transmission between the servo motor (2) and the main spindle (33); the linear motor (18) is mounted on the bed (1) and is used to drive the air-bearing mechanism. The worktable (13) performs linear reciprocating motion; the bearing support seat (7) serves as the core radial support component of the spindle (33) and is equipped with matching bearing end caps, including a left bearing end cap (6) and a right bearing end cap (8) fixed to the left and right ends of the bearing support seat (7), which are used to achieve bearing sealing protection and axial auxiliary limiting, and cooperate with the bearing support seat (7) to complete the stable support of the spindle (33); the inner hole of the bearing support seat (7) is interference-fitted with the outer ring of the angular contact ball bearing (29) on the spindle (33) to achieve radial positioning of the spindle (33); where left and right are the left and right sides along the length direction of the marble bed (1).

4. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 3, characterized in that, The clamping components include a four-jaw chuck (9), a workpiece clamping fixture (10), and a rotary clamping cylinder (11) mounted on the workpiece clamping fixture (10). The four-jaw chuck (9) is coaxially mounted on the rightmost end of the spindle (33). The coaxiality of the workpiece and the spindle (33) is ensured by adjusting the radial extension of the four jaws in the four-jaw chuck (9). The workpiece clamping fixture (10) is adapted to the nut (34) to be tested, and the rotary clamping cylinder (11) is symmetrically arranged on it. The two work together to achieve axial fixation of the nut (34) to be tested.

5. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 4, characterized in that, The axial moving component and its supporting auxiliary components include an air-floating worktable (13), a hydraulic buffer (15), a buffer support (14), a double-axis linear guide rail (19), a limit slider (20), a drag chain (17), a drag chain adapter plate (16), and a reference plate (12). The air-floating worktable (13) is mounted on the air-floating guide rail on the marble bed (1) and is fixedly connected to the mover of the linear motor (18). The linear motor (18) is used to drive the air-floating worktable (13) to perform linear reciprocating motion. The buffer support (14) is fixedly mounted on the marble bed (1), and the hydraulic buffer (15) is mounted on the buffer. The impactor support (14) is mounted on the air-bearing guide rail (19), and the limiting slider (20) is mounted on the air-bearing guide rail (19) and linked with the air-bearing worktable (13) to limit the travel of the air-bearing worktable (13). The drag chain adapter plate (16) is fixedly mounted on one side of the air-bearing worktable (13), and the drag chain (17) is fixedly connected to the drag chain adapter plate (16) to store pipelines and move synchronously with the air-bearing worktable (13). The reference plate (12) is mounted on the left side of the air-bearing worktable (13) and coincides with the left end face of the air-bearing worktable (13) as the reference surface for dial gauge measurement.

6. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 5, characterized in that, The measuring components include a circular grating (26), a reading (22), a circular grating positioning sleeve (27), a tightening nut (25), a reading head bracket (23), a fiber laser ruler (4), a reflector (35), a measuring bracket (45), a floating sleeve (43), a handle (46), a push rod (41), a measuring rod (40), a return spring (42), a locking sleeve (39), a measuring head (38), a torsion spring (37), and a torsion spring pressure block (36). The circular grating (26) is mounted on the circular grating positioning sleeve (27) and is used as an angular reference for measuring the rotation of the measuring nut (34); the circular grating positioning sleeve (27) is mounted on the main shaft (33) and close to the left end of the main shaft; a stop device is fitted on the circular grating positioning sleeve (27) to limit its radial movement; the tightening nut (25) is screwed onto the left side of the circular grating positioning sleeve (27) through the thread on the main shaft (33) to limit the axial movement of the circular grating positioning sleeve (27); the reading head bracket (23) is fixed on the left end cover (6) of the bearing, and the reading head (22) is mounted on... The reading head bracket (23) is used to read the angle signal of the circular grating (26); the fiber laser ruler (4) is installed on the laser ruler support (3) to stabilize the linear displacement of the air-bearing worktable (13) and provide a precise length reference for the device; the reflector (35) is installed on the left end face of the measuring rod (40) and cooperates with the fiber laser ruler (4) to realize displacement detection; the measuring bracket (45) is installed on the air-bearing worktable (13) and maintains coaxiality with the main shaft (33); the floating sleeve adopts a splined shaft (43) and splined nut (44) to form a splined pair structure, and is coaxial with the measuring support. The bracket (45) is coaxially mounted, and the end flange of the spline nut (44) is fixedly connected to the left side of the measuring bracket (45); the measuring rod (40) is installed inside the spline shaft (43) in a tight fit manner, and is axially fixed by the locking sleeve (39); through the guiding effect of the spline pair, the spline shaft (43) can drive the measuring rod (40) to make a smooth axial reciprocating movement along the axis of the measuring bracket (45), while restricting the circumferential rotation of the spline shaft (43) relative to the measuring bracket (45); the push rod (41) is installed inside the measuring rod (40), and is connected by the thread of the handle (46) installed on the right side of the measuring bracket (45). The feed action drives the probe (40) to move axially; the reset spring (42) is fixed by inserting a hinge into the slot of the push rod (41) to achieve self-reset after the push rod (41) moves forward axially; the probe (38) is installed in the square hole at the left end of the probe (40); the torsion spring (37) is supported between the probe (38) and the probe (40), and the fixed side arm of the torsion spring (37) is abutted in the arc-shaped slot opened at the left end of the probe (40), and the force-applying side arm is hooked into the slot of the probe (38) carrier; the torsion spring pressure block (36) is in contact with the end face of the torsion spring (37) to prevent the torsion spring (37) from moving axially.

7. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 6, characterized in that, The emitting end face of the fiber laser ruler (4) and the reflecting end face of the reflector (35) are on the same straight line. The main shaft (33) is set as a hollow structure. The measuring light emitted by the fiber laser ruler (4) passes through the hollow main shaft (33) along the axial direction of the nut (34) being measured, so that the reference line of the measuring light coincides with the measuring reference axis of the inner raceway of the nut (34) being measured, and no Abbe error is generated.

8. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 7, characterized in that, The connection between the push rod (41) and the probe (38) is provided with a wedge-shaped clamping structure. The wedge-shaped clamping structure is composed of an inclined groove opened in the probe (38) and a conical head of the push rod (41). The inclination angle of the inclined groove matches the taper of the conical head. The radial positioning of the probe (38) is achieved by the tangential contact between the conical head and the inclined groove. At the same time, with the elastic force of the torsion spring (37), the probe (38) maintains a stable posture during the measurement process without radial movement.

9. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 8, characterized in that, The screw handle (46) and the spline shaft (43) are connected by a fine-pitch ordinary thread to achieve helical feeding. The lead accuracy of the fine-pitch thread is not lower than IT5 grade. The outer circumference of the screw handle (46) is provided with an anti-slip knurled structure. By rotating the screw handle (46), the push rod (41) is driven to move axially. The conical head of the push rod (41) makes a wedge-shaped feed along the inclined groove, pressing the probe (38) to the preset measurement position of the inner raceway of the nut. The feed amount is precisely controlled by the rotation angle of the screw handle (46) to adapt to the measurement position adjustment requirements of the inner raceway of different specifications of nuts.

10. The dynamic measuring device for the inner raceway stroke error of a nut according to claim 9, characterized in that, The torsion spring pressure block (36) is threaded to the end of the measuring rod (40) via an internal thread. Rotating the torsion spring pressure block (36) can adjust the contact pressure between it and the end face of the torsion spring (37).

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