A stress-strain measuring device for a flexspline of a harmonic reducer

Abstract

The present application relates to the technical field of harmonic reducer measurement, and discloses a kind of harmonic reducer flexspline stress strain measuring device including base, its bearing surface middle part installs base, installation platform top installs driving motor, motor rotor coaxial connection cam, cam outside sleeve set flexspline;Base inner cavity middle part inserts and inserts assembly seat, two-way screw is inserted in assembly seat, its both sides are screwed slider, slider top end connects vertical plate, vertical plate outer surface is equipped with mounting block;Mounting block side surface is equipped with analog steel wheel, its inner wall is opened tooth slot, flow channel is opened between middle part tooth slot, chuck is inserted in flow channel;Trigger lever is inserted in chuck, its trigger end penetrates flow channel, the other end is coaxially connected piston, pressure cavity is opened in mounting block and top is equipped with pressure sensor.The device is accurately fixed with radial constraint flexspline by two-way screw driven analog steel wheel, obtains stress strain data by simulating real working condition, and pressure change is captured by pressure sensor and combined with venturi model to deduce real-time stress strain, realize non-contact measurement.

Description

Technical Field

[0001] This invention relates to the field of harmonic reducer measurement technology, specifically to a device for measuring the stress and strain of a flexural wheel in a harmonic reducer. Background Technology

[0002] Harmonic reducers, as core components in the field of precision transmission, are widely used in high-precision applications such as industrial robots and aerospace. The stress-strain state of their flexspline directly affects the reducer's performance and lifespan. Therefore, accurately measuring the stress-strain distribution of the flexspline during operation is a key technical requirement for optimizing harmonic reducer design and improving reliability.

[0003] Common stress-strain measurement devices for flexure wheels in harmonic reducers often employ direct-contact sensors or simplified constraint structures, such as fixing the flexure wheel with a rigid clamp and arranging strain gauges for measurement. However, rigid clamps cannot simulate the actual radial force distribution when the steel wheel and flexure wheel mesh, leading to stress distortion in the flexure wheel during measurement due to insufficient or excessive constraint, making it difficult to reflect the stress state under real working conditions. Simultaneously, contact sensors directly attached to the flexure wheel surface interfere with its dynamic deformation characteristics, especially in high-speed operation or micro-deformation scenarios. The sensor's own weight or stiffness may cause measurement errors, and its sensitivity to detecting small strains is low, failing to meet the requirements for high-precision measurement and the operational requirements of harmonic reducer measurements. Therefore, a stress-strain measurement device for flexure wheels in harmonic reducers is proposed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a stress-strain measurement device for the flexible wheel of a harmonic reducer, thereby solving the technical problems of stress distortion and dynamic interference during measurement.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a stress-strain measuring device for a harmonic reducer flexural wheel, comprising: A base, wherein a base is installed in the middle of the bearing surface of the base, a mounting platform is installed on the top side of the base, a drive motor is installed on the top of the mounting platform, a cam is coaxially connected to the rotor of the drive motor, and a flexible wheel is sleeved on the outside of the cam; An assembly base is inserted into the middle of the inner cavity of the base. A bidirectional lead screw is inserted inside the assembly base. Slider blocks are screwed to both sides of the outer side of the bidirectional lead screw. A vertical plate is connected to the top of each slider. Mounting blocks are installed on the outer surface of each vertical plate. A simulated steel wheel is installed on the side of the mounting block. The inner wall of the simulated steel wheel is provided with tooth grooves. Flow channels are provided between the middle tooth grooves inside the simulated steel wheel. A chuck is inserted inside the flow channels. A trigger rod is inserted inside the chuck, with the trigger end of the trigger rod passing through the interior of the flow channel. The other end of the trigger rod is coaxially connected to a piston. A pressure chamber is opened inside the mounting block, and a pressure sensor is installed on the top of the mounting block.

[0006] Preferably, the threads on both sides of the bidirectional lead screw are arranged in opposite directions. The operating end of the bidirectional lead screw passes through the corresponding position of the base. A handwheel is coaxially connected to the operating end of the bidirectional lead screw. The middle part of the bidirectional lead screw is connected to the mounting base through a bearing. The reverse threads on both sides of the bidirectional lead screw, in conjunction with the handwheel, can conveniently and accurately control the synchronous reverse movement of the sliders on both sides, realize the rapid and stable opening and closing of the simulated steel wheel, and improve the efficiency of measurement operation and the reliability of the flexible wheel fixation.

[0007] Preferably, there are at least two sets of flow channels and trigger rods. The trigger ends of the trigger rods are all tapered structures. A first disc is fitted around the outside of the trigger rod. The trigger ends of the trigger rods penetrate one-third of the depth of the simulated steel wheel tooth groove. The combination of multiple sets of flow channels and tapered trigger rods can comprehensively capture the deformation of the flexible wheel at different positions, accurately transmit deformation signals, and ensure comprehensive and accurate stress and strain measurement.

[0008] Preferably, a first spring is fitted around the trigger rod at a position between the first disk and the chuck. The two ends of the first spring are connected to the outer surfaces of the first disk and the chuck, respectively. The inner cavity of the flow channel is connected to the interior of the pressure chamber. The first spring allows the trigger rod to be flexibly reset within the flow channel, ensuring the continuity of the measurement process. The connection between the flow channel and the pressure chamber facilitates the transmission of air pressure signals and provides stable conditions for accurately recalculating stress and strain.

[0009] Preferably, the inner cavities of the slider and the base are both trapezoidal structures. Ribs are welded to both sides of the connection between the slider and the upright plate. Assembly cylinders are connected to the outer side of the upright plate. The trapezoidal structure slider and the base are stably matched. The ribs enhance the connection strength between the slider and the upright plate. The assembly cylinders facilitate the installation of subsequent components, thereby improving the overall structural stability and durability of the measuring device.

[0010] Preferably, each assembly cylinder has an insert shaft inserted inside, with both ends of the insert shaft penetrating both ends of the assembly cylinder. Each insert shaft facing the drive motor rotor is connected to a snap-fit ​​connector, and each snap-fit ​​connector has a sealing gasket inserted inside. The insert shaft, in conjunction with the snap-fit ​​connector and the sealing gasket, can be stably snapped onto the outside of the drive motor rotor, effectively preventing airflow leakage and improving the reliability of measurement data.

[0011] Preferably, a second disc is fitted around the outside of the insertion shaft at a position inside the assembly cylinder, and a second spring is fitted around the outside of the insertion shaft at a position between the second disc and the inner wall of the assembly cylinder. The two ends of the second spring are respectively connected to the second disc and the inner wall of the assembly cylinder. The second disc and the second spring cooperate to allow the insertion shaft to move elastically inside the assembly cylinder, so that the sealing gasket is always in close contact with the outside of the rotor of the drive motor.

[0012] Preferably, air holes are provided inside the mounting block at positions corresponding to the pressure chamber. The air holes are connected to the inside of the pressure chamber, and a sealing plug is inserted at the air inlet of the air hole. The detection end of the pressure sensor penetrates through the inside of the pressure chamber. The air holes facilitate the adjustment of the pressure inside the pressure chamber. Before measurement, air can be vented or injected into the pressure chamber through the air holes to maintain the pressure inside the pressure chamber at a stable value, which facilitates the detection of subsequent pressure changes.

[0013] Preferably, both sides of the simulated steel wheel are equipped with sealing covers, and the rotor and flexible wheel of the drive motor pass through the inside of the sealing covers. A positioning groove is opened on the contact surface of one side of the simulated steel wheel, and a positioning protrusion is installed on the contact surface of the simulated steel wheel on the other side at the position corresponding to the positioning groove. The positioning groove and the positioning protrusion cooperate to ensure that the simulated steel wheel is accurately connected, ensure accurate radial constraint during measurement, and improve the accuracy of stress and strain measurement.

[0014] Preferably, there are at least two sets of positioning grooves and positioning protrusions. Both positioning grooves and positioning protrusions have toothed structures. The inner wall of each positioning groove is lined with a sealing gasket. Multiple sets of toothed positioning grooves cooperate with the positioning protrusions to enhance the stability of the simulated steel wheel connection. The sealing gaskets prevent leakage at the connection and ensure a stable measurement environment.

[0015] Compared with the prior art, the present invention provides a stress-strain measurement device for the flexible wheel of a harmonic reducer, which has the following advantages: This stress-strain measurement device for the flexible wheel of a harmonic reducer uses a bidirectional lead screw to drive a slider in a synchronous opening and closing motion. This allows a simulated steel wheel to be clamped on the outside of the flexible wheel via a vertical plate, achieving precise fixation and radial constraint simulation of the flexible wheel. Subsequently, the flexible wheel deforms by rotating a cam driven by a motor. Since the tooth grooves of the simulated steel wheel can reproduce the actual meshing state between the steel wheel and the flexible wheel, the flexible wheel experiences a radial force distribution consistent with real working conditions during the measurement process. This avoids stress distortion caused by insufficient or excessive constraint in traditional measurement methods, thus obtaining stress-strain data that is closer to actual operation. During the deformation of the flexible wheel, it squeezes the trigger rod, which in turn drives the piston to move, squeezing the gas inside the pressure chamber and generating pressure fluctuations. At the same time, the pressure sensor captures the changes in air pressure and, combined with the Venturi tube fluid dynamics model, can indirectly infer the real-time stress-strain state of the flexible wheel, achieving a non-contact measurement method. This not only avoids interference from direct sensor contact with the dynamic characteristics of the flexible wheel but also improves the detection sensitivity of minute deformations through the amplification effect of the air pressure signal. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the mounting platform and drive motor structure of the present invention; Figure 3 This is a schematic cross-sectional view of the base structure of the present invention; Figure 4 This is a schematic diagram of the simulated steel wheel structure of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the simulated steel wheel of the present invention; Figure 6 This is a schematic cross-sectional view of the assembly cylinder structure of the present invention; Figure 7 This is a schematic diagram of the positioning groove and positioning protrusion structure of the present invention.

[0017] In the diagram: 1. Base; 2. Base plate; 3. Mounting platform; 4. Drive motor; 5. Cam; 6. Flexible wheel; 7. Assembly seat; 8. Two-way lead screw; 81. Handwheel; 9. Slider; 10. Vertical plate; 11. Mounting block; 111. Pressure chamber; 112. Air hole; 12. Simulated steel wheel; 121. Positioning groove; 122. Positioning protrusion; 13. Flow channel; 14. Chuck; 15. Trigger rod; 16. Piston; 17. First disc; 18. First spring; 19. Pressure sensor; 20. Assembly cylinder; 21. Insert shaft; 22. Snap connector; 23. Sealing gasket; 24. Second disc; 25. Second spring. Detailed Implementation

[0018] 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, and 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.

[0019] This invention provides a technical solution: a stress-strain measuring device for a harmonic reducer flexure wheel, comprising a base 1, a base 2, a mounting platform 3, a drive motor 4, a cam 5, a flexure wheel 6, an assembly seat 7, a bidirectional lead screw 8, a handwheel 81, a slider 9, a vertical plate 10, a mounting block 11, a pressure chamber 111, an air hole 112, a simulated steel wheel 12, a positioning groove 121, a positioning protrusion 122, a flow channel 13, a chuck 14, a trigger rod 15, a piston 16, a first disc 17, a first spring 18, a pressure sensor 19, an assembly cylinder 20, a insertion shaft 21, a snap-fit ​​connector 22, a sealing washer 23, a second disc 24, and a second spring 25. Please see Figure 1 A base 2 is installed in the middle of the bearing surface of the base 1, and a mounting platform 3 is installed on the top side of the base 1. Please refer to [link / reference]. Figure 2 A drive motor 4 is installed on the top of the mounting platform 3. The rotor of the drive motor 4 is coaxially connected to a cam 5, and a flexible wheel 6 is sleeved on the outside of the cam 5. Please see Figure 3 The mounting base 7 is inserted into the middle of the inner cavity of the base 2. A double-acting screw 8 is inserted inside the mounting base 7. Slider 9 is screwed to both sides of the outer side of the double-acting screw 8. A vertical plate 10 is connected to the top of each slider 9. Mounting blocks 11 are installed on the outer surface of each vertical plate 10. The threads on both sides of the double-acting screw 8 are set in opposite directions. The operating end of the double-acting screw 8 passes through the corresponding position of the base 2. A handwheel 81 is coaxially connected to the operating end of the double-acting screw 8. The middle part of the double-acting screw 8 is connected to the mounting base 7 through a bearing. Please see Figure 4 The simulated steel wheel 12 is mounted on the side of the mounting block 11. The inner wall of the simulated steel wheel 12 has toothed grooves. (See attached image.) Figure 5 The simulated steel wheel 12 has flow channels 13 located between the central tooth grooves, and a chuck 14 is inserted inside the flow channels 13. The trigger rod 15 is inserted inside the chuck 14. The trigger end of the trigger rod 15 passes through the interior of the flow channel 13, and the other end of the trigger rod 15 is coaxially connected to the piston 16. A pressure chamber 111 is formed inside the mounting block 11. Please refer to [link / reference]. Figure 4 A pressure sensor 19 is installed on the top of the mounting block 11; Please see Figure 5The number of flow channels 13 and trigger rods 15 is at least 2 sets. The trigger ends of the trigger rods 15 are all tapered structures. A first disc 17 is fitted on the outside of the trigger rod 15. The trigger end of the trigger rod 15 penetrates one-third of the tooth groove depth of the simulated steel wheel 12. A first spring 18 is fitted on the outside of the trigger rod 15 at the position between the first disc 17 and the chuck 14. The two ends of the first spring 18 are respectively connected to the outer surfaces of the first disc 17 and the chuck 14. The inner cavity of the flow channel 13 is connected to the inside of the pressure chamber 111. By rotating the bidirectional lead screw 8 to drive the slider 9 to perform synchronous opening and closing movements, the simulated steel wheel 12 can be clamped on the outside of the flexible wheel 6 by the vertical plate 10, realizing the precise fixation and radial constraint simulation of the flexible wheel 6. Subsequently, the cam 5 can be rotated by the drive motor 4, thereby causing the flexible wheel 6 to deform. Since the tooth groove of the simulated steel wheel 12 can restore the actual meshing state between the steel wheel and the flexible wheel 6, the flexible wheel 6 bears the same radial force distribution as the real working condition during the measurement process, avoiding the stress distortion caused by insufficient or excessive constraint in the traditional measurement method, thus obtaining stress and strain data that are closer to actual operation. During the deformation of the flexible wheel 6, the trigger rod 15 will be squeezed, which can push the piston 16 to move, squeezing the gas inside the pressure chamber 111 to generate pressure fluctuations. At the same time, the pressure sensor 19 can indirectly infer the real-time stress and strain state of the flexible wheel 6 by capturing the air pressure change and combining it with the Venturi tube fluid dynamics model, achieving a non-contact measurement method. This not only avoids the interference of direct sensor contact on the dynamic characteristics of the flexible wheel, but also improves the detection sensitivity of small deformations through the amplification effect of the air pressure signal. Both the inner cavities of slider 9 and base 2 are trapezoidal structures. Ribs are welded to both sides of the connection between slider 9 and vertical plate 10. Assembly cylinders 20 are connected to the outer sides of vertical plate 10. (See also...) Figure 6 Each assembly cylinder 20 has an insert shaft 21 inserted inside. Both ends of the insert shaft 21 pass through both ends of the assembly cylinder 20. The end of the insert shaft 21 facing the rotor of the drive motor 4 is connected to a snap connector 22. A sealing gasket 23 is inserted inside the snap connector 22. A second disc 24 is sleeved on the outside of the insert shaft 21 inside the assembly cylinder 20. A second spring 25 is sleeved on the outside of the insert shaft 21 between the second disc 24 and the inner wall of the assembly cylinder 20. Both ends of the second spring 25 are connected to the second disc 24 and the inner wall of the assembly cylinder 20, respectively. Please see Figure 5 Air holes 112 are provided inside the mounting block 11 at positions corresponding to the pressure chamber 111. The air holes 112 are connected to the interior of the pressure chamber 111, and sealing plugs are inserted at the air inlets of the air holes 112. The detection end of the pressure sensor 19 penetrates the interior of the pressure chamber 111 (see figure). Sealing covers are installed on both sides of the simulated steel wheel 12. The rotor of the drive motor 4 and the flexible wheel 6 both penetrate the interior of the sealing covers (see figure). Figure 7One side of the simulated steel wheel 12 has a positioning groove 121 on its contact surface, and the other side of the simulated steel wheel 12 has a positioning protrusion 122 at the corresponding position of the positioning groove 121 on its contact surface. There are at least two sets of positioning grooves 121 and positioning protrusions 122. Both positioning grooves 121 and positioning protrusions 122 have tooth-like structures, and the inner wall of the positioning groove 121 is lined with a sealing gasket.

[0020] This scheme uses a bidirectional lead screw 8 to drive a slider 9 to open and close synchronously, allowing the simulated steel wheel 12 to be clamped on the outside of the flexible wheel 6 via the vertical plate 10. This achieves precise fixation and radial constraint simulation of the flexible wheel 6. Subsequently, the drive motor 4 drives the cam 5 to rotate, causing the flexible wheel 6 to deform. Since the tooth grooves of the simulated steel wheel 12 can reproduce the actual meshing state between the steel wheel and the flexible wheel 6, the flexible wheel 6 experiences a radial force distribution consistent with the real working condition during the measurement process. This avoids stress distortion caused by insufficient or excessive constraint in traditional measurement methods, thus obtaining stress and strain data that are closer to actual operation. During the deformation of the flexible wheel 6, it squeezes the trigger rod 15, which in turn pushes the piston 16 to move, squeezing the gas inside the pressure chamber 111 and generating pressure fluctuations. At the same time, the pressure sensor 19 captures the changes in air pressure and, combined with the Venturi tube fluid dynamics model, can indirectly infer the real-time stress and strain state of the flexible wheel 6, achieving a non-contact measurement method. This not only avoids interference from direct sensor contact with the dynamic characteristics of the flexible wheel, but also improves the detection sensitivity of small deformations through the amplification effect of the air pressure signal.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0022] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for measuring the stress and strain of a flexural wheel in a harmonic reducer, characterized in that, include: A base (1) is provided with a base (2) installed in the middle of the bearing surface of the base (1). A mounting platform (3) is provided on the top side of the base (1). A drive motor (4) is installed on the top of the mounting platform (3). A cam (5) is coaxially connected to the rotor of the drive motor (4). A flexible wheel (6) is sleeved on the outside of the cam (5). The mounting base (7) is inserted into the middle of the inner cavity of the base (2). A two-way lead screw (8) is inserted inside the mounting base (7). A slider (9) is screwed onto both sides of the outside of the two-way lead screw (8). A vertical plate (10) is connected to the top of each slider (9). An installation block (11) is installed on the outer surface of each vertical plate (10). A simulated steel wheel (12) is installed on the side of the mounting block (11). The inner wall of the simulated steel wheel (12) is provided with tooth grooves. The interior of the simulated steel wheel (12) is provided with flow channels (13) between the middle tooth grooves. A chuck (14) is inserted inside the flow channels (13). A trigger rod (15) is inserted inside the chuck (14). The trigger end of the trigger rod (15) passes through the interior of the flow channel (13). The other end of the trigger rod (15) is coaxially connected to a piston (16). A pressure chamber (111) is opened inside the mounting block (11). A pressure sensor (19) is installed on the top of the mounting block (11).

2. The stress-strain measuring device for a harmonic reducer flexural gear as described in claim 1, characterized in that: The threads on both sides of the bidirectional lead screw (8) are arranged in opposite directions. The operating end of the bidirectional lead screw (8) passes through the corresponding position of the base (2). The operating end of the bidirectional lead screw (8) is coaxially connected to a handwheel (81). The middle part of the bidirectional lead screw (8) is connected to the mounting base (7) through a bearing.

3. The stress-strain measuring device for a harmonic reducer flexural gear as described in claim 1, characterized in that: The number of the flow channel (13) and the trigger rod (15) is at least 2 sets. The trigger end of the trigger rod (15) is a conical structure. The trigger rod (15) is fitted with a first disc (17). The trigger end of the trigger rod (15) penetrates one-third of the tooth groove depth of the simulated steel wheel (12).

4. The stress-strain measuring device for a harmonic reducer flexural wheel according to claim 3, characterized in that: The trigger rod (15) is fitted with a first spring (18) at the position between the first disk (17) and the chuck (14). The two ends of the first spring (18) are connected to the outer surfaces of the first disk (17) and the chuck (14) respectively. The inner cavity of the flow channel (13) is connected to the inside of the pressure chamber (111).

5. The stress-strain measuring device for a harmonic reducer flexural gear according to claim 1, characterized in that: The inner cavities of the slider (9) and the base (2) are both trapezoidal structures. Ribs are welded on both sides of the connection between the slider (9) and the upright plate (10). Assembly cylinders (20) are connected to the outer side of the upright plate (10).

6. The stress-strain measuring device for a harmonic reducer flexural gear according to claim 5, characterized in that: Each assembly cylinder (20) has a shaft (21) inserted inside. Both ends of the shaft (21) pass through both ends of the assembly cylinder (20). Each end of the shaft (21) facing the rotor of the drive motor (4) is connected to a connector (22). Each connector (22) has a sealing gasket (23) inserted inside.

7. The stress-strain measuring device for a harmonic reducer flexural wheel according to claim 6, characterized in that: A second disc (24) is fitted on the outside of the insert shaft (21) inside the assembly cylinder (20). A second spring (25) is fitted on the outside of the insert shaft (21) between the second disc (24) and the inner wall of the assembly cylinder (20). The two ends of the second spring (25) are connected to the second disc (24) and the inner wall of the assembly cylinder (20), respectively.

8. The stress-strain measuring device for a harmonic reducer flexural wheel according to claim 1, characterized in that: Air holes (112) are provided inside the mounting block (11) at positions corresponding to the pressure chamber (111). The air holes (112) are connected to the inside of the pressure chamber (111), and a sealing plug is inserted at the air inlet of the air hole (112). The detection end of the pressure sensor (19) penetrates the inside of the pressure chamber (111).

9. The stress-strain measuring device for a harmonic reducer flexural wheel according to claim 1, characterized in that: Both sides of the simulated steel wheel (12) are equipped with sealing covers. The rotor of the drive motor (4) and the flexible wheel (6) pass through the inside of the sealing cover. A positioning groove (121) is opened on the contact surface of the simulated steel wheel (12) on one side. Positioning protrusions (122) are installed on the contact surface of the simulated steel wheel (12) on the other side corresponding to the positioning groove (121).

10. The stress-strain measuring device for a harmonic reducer flexural wheel according to claim 9, characterized in that: The number of positioning grooves (121) and positioning protrusions (122) is at least 2 sets. Both positioning grooves (121) and positioning protrusions (122) have tooth-like structures. The inner wall of the positioning grooves (121) is covered with sealing gaskets.

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