A detection instrument integrating a high-precision angle encoder and a torque sensor

Abstract

The utility model relates to robot joint technical field especially, is involved in a kind of detection instrument of integrated high-precision angle encoder and torque sensor, including torque sensor, the intermediate position of torque sensor is equipped with torque sensor shaft, one end of torque sensor shaft is equipped with expansion inner sleeve, the outside of expansion inner sleeve is equipped with expansion outer sleeve, and the front end outer wall of expansion outer sleeve is fixedly installed with encoder, and one side of the encoder is correspondingly provided with reading head.The utility model is equipped with expansion inner sleeve, expansion outer sleeve, high-strength bolt, nut and forms expansion coupling structure, can improve positioning accuracy, eliminates the weakening of keyway to the strength of shaft and the gap existing in key coupling, can realize the extremely high concentricity of shaft and wheel hub, transmission is stable, especially suitable for high-speed precision transmission.

Description

Technical Field

[0001] This utility model relates to the field of robot joint technology, and in particular to a detection instrument that integrates a high-precision angle encoder and a torque sensor. Background Technology

[0002] Harmonic reducers, with their unique advantages of zero backlash, high precision, high torque density, and compact structure, have become an indispensable "core joint" in modern robots. They have greatly promoted the development of robotics technology towards high precision, lightweight, and high performance, and are a key guarantee for robots to perform complex tasks accurately and flexibly. High-precision angle and torque sensors are the "eyes" and "scales" in the field of robot joint testing. They transform the invisible mechanical properties (torque, stiffness, friction) and motion properties (angle, velocity) inside the joint into quantifiable and analyzable data. From R&D and production to quality inspection, they are used throughout the entire lifecycle of robot joint performance evaluation and are a key tool for improving robot performance, reliability, and safety.

[0003] A search revealed a servo encoder integrated robot joint with publication number 202510921096.3. The torque sensor serves as the output terminal and is simultaneously connected to the flex wheel of the harmonic reducer and the hollow shaft. The motor encoder read head, joint encoder read head, and servo driver are integrated into one unit. Therefore, the motor encoder code disk and the joint encoder code disk are coaxial and nested, with the working surface of the motor encoder code disk facing and maintaining a gap with the motor encoder read head on the servo driver. Similarly, the joint encoder code disk faces and maintains a gap with the joint encoder read head. Integrating the motor encoder read head, joint encoder read head, and servo driver into one unit eliminates the need for a separate signal processing PCBA for the encoder read head. Furthermore, the coaxial nesting of the joint encoder code disk and the motor encoder code disk eliminates the need for additional axial dimensions, further reducing the size and volume of the joint.

[0004] In existing technologies, the connection between torque sensors and the flexible wheel and hollow shaft of harmonic reducers does not employ a shrink-fit coupling structure, but most likely relies on traditional key connections or rigid flange connections. Traditional key connections require machining keyways on the shaft and hub, inevitably resulting in assembly gaps (research on key connections at Changsha University of Science and Technology confirms that loose key connections rely on lateral compression for load bearing, resulting in fitting gaps; wedge key connections, although tight connections, have extremely poor centering), making it impossible to achieve high-precision concentricity between the shaft and hub. This gap causes radial runout during robot joint operation, leading to uneven force on the torque sensor and causing strain gauge measurement errors (single-axis torque sensors rely on strain gauge resistance changes for measurement, and force eccentricity directly affects the output accuracy of the bridge circuit); on the other hand, it causes fluctuations in the gap between the encoder code disk and the reader, resulting in distortion of the angle measurement signal. Summary of the Invention

[0005] The purpose of this invention is to provide a detection instrument that integrates a high-precision angle encoder and a torque sensor. The expansion coupling structure uses a "sloping plane pressure boosting effect" to form a gapless interference fit, which can achieve extremely high alignment, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a detection instrument integrating a high-precision angle encoder and a torque sensor, comprising a torque sensor, a torque sensor shaft installed in the middle of the torque sensor, an expansion inner sleeve fitted at one end of the torque sensor shaft, an expansion outer sleeve fitted on the outer side of the expansion inner sleeve, an encoder fixedly installed on the front outer wall of the expansion outer sleeve, and a reading head correspondingly provided on one side of the encoder.

[0007] Preferably, a torque sensor end cover is fixedly installed on the outside of the torque sensor, and a read head frame mounting flange is fixedly installed at the stop of the torque sensor end cover.

[0008] Preferably, a head spacing adjustment assembly is installed on the side wall of the head mounting flange, the head spacing adjustment assembly including a head mount, an adjustment slider, a slide rail and positioning bolts.

[0009] Preferably, the slide rail is fixedly installed on the side wall of the reading head frame mounting flange, and an adjusting slider is slidably installed on the slide rail. The adjusting slider has a positioning bolt that abuts against the end face of the slide rail.

[0010] Preferably, the read head frame is fixedly mounted on the side wall of the adjusting slider, and the read head frame is fixedly connected to the read head.

[0011] Preferably, the expansion sleeve and the expansion inner sleeve are fixedly connected by high-strength bolts and nuts, and the contact surface between the expansion sleeve and the expansion inner sleeve is a conical surface.

[0012] Preferably, an adjusting washer is provided at one end of the expansion sleeve near the torque sensor, and the adjusting washer is sleeved on the torque sensor shaft.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This utility model utilizes an expansion coupling structure comprised of an inner expansion sleeve, an outer expansion sleeve, high-strength bolts, and nuts. This structure improves positioning accuracy, eliminates the weakening effect of keyways on shaft strength, and removes the clearance inherent in keyed connections. It achieves extremely high concentricity between the shaft and hub, resulting in smooth transmission, making it particularly suitable for high-speed precision transmission. Furthermore, the absence of keyways on the shaft and hub avoids stress concentration at the keyway root, improving the fatigue strength of both and extending their service life. The connection also boasts high strength and load-bearing capacity, capable of transmitting large torques, axial forces, and impact loads. Assembly and disassembly are simple, requiring only tightening or loosening the bolts, and the coupling is reusable. This is highly advantageous for equipment requiring frequent maintenance and parts replacement. Additionally, under extreme overload conditions, the expansion sleeve will slip, protecting other critical components on the main unit from damage. Moreover, shafts of the same inner diameter can be adapted to different torque requirements by selecting different expansion sleeve models, offering good versatility. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is an internal sectional view of the present invention.

[0017] Figure 2 This is a side view of the structure of this utility model;

[0018] Figure 3 This is an enlarged structural schematic diagram of the read head spacing adjustment component of this utility model.

[0019] Explanation of reference numerals in the attached figures:

[0020] 1. Torque sensor; 2. Reader head mounting flange; 3. Adjusting washer; 4. Encoder; 5. Reader head; 6. Reader head spacing adjustment assembly; 601. Reader head frame; 602. Adjusting slider; 603. Slide rail; 604. Positioning bolt; 7. Expansion sleeve; 8. Expansion inner sleeve; 9. Torque sensor shaft; 10. Torque sensor end cover. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] This utility model provides a technical solution:

[0023] Please see Figures 1 to 2 A detection instrument integrating a high-precision angle encoder and a torque sensor includes a torque sensor 1, a torque sensor shaft 9 installed in the middle of the torque sensor 1, an inner expansion sleeve 8 fitted at one end of the torque sensor shaft 9, an outer expansion sleeve 7 fitted on the outer side of the inner expansion sleeve 8, an encoder 4 fixedly installed on the front outer wall of the outer expansion sleeve 7, a reader head 5 correspondingly provided on one side of the encoder 4, a torque sensor end cover 10 fixedly installed on the outside of the torque sensor 1, a reader head mounting flange 2 fixedly installed at the stop of the torque sensor end cover 10, the outer expansion sleeve 7 and the inner expansion sleeve 8 are fixedly connected by high-strength bolts and nuts, the contact surface between the outer expansion sleeve 7 and the inner expansion sleeve 8 is a conical surface, an adjusting washer 3 is provided at the end of the inner expansion sleeve 8 near the torque sensor 1, the adjusting washer 3 is fitted on the torque sensor shaft 9, the relative position of the encoder 4 and the reader head 5 is adjusted by adjusting the adjusting washer 3, and a hub is fitted on the outside of the outer expansion sleeve 7.

[0024] By adopting the above technical solution, during use, the adjusting washer 3 is fitted onto the end of the torque sensor shaft 9 near the torque sensor 1. Then, the inner expansion sleeve 8 and the outer expansion sleeve 7 are sequentially fitted onto the torque sensor shaft 9, so that the inner expansion sleeve 8 is in contact with the end face of the adjusting washer 3. The encoder 4 is fixedly installed on the front outer wall of the outer expansion sleeve 7, and the hub is fitted onto the outside of the outer expansion sleeve 7. Finally, the reading head frame mounting flange 2 is fixed by the stop of the torque sensor end cover 10, completing the initial alignment of the reading head 5 and the encoder 4. The outer expansion sleeve 7 and the inner expansion sleeve 8 are pulled closer axially by high-strength bolts and nuts. Since the contact surface of the two is a conical surface, the axial tension will be converted into radial pressure. The outer expansion sleeve 7 expands outward to hug the inner hole of the hub, and the inner expansion sleeve 8 contracts inward to hug the torque sensor shaft 9. Finally, a clearance-free interference fit is formed between the shaft, the outer expansion sleeve, and the hub, realizing the rigid transmission of torque. During this stage, the adjusting washer 3 is adjusted by thickness compensation to initially calibrate the axial relative position of the encoder 4 and the reader 5, ensuring initial alignment accuracy;

[0025] The expansion coupling structure consists of an inner expansion sleeve 8, an outer expansion sleeve 7, high-strength bolts, and nuts. During assembly, the inner expansion sleeve 8 is placed on the torque sensor shaft 9, and the hub is placed on the outer expansion sleeve 7. The entire assembly is then aligned and placed in the predetermined position. When the high-strength bolts are tightened according to the specified torque and sequence, the tension of the high-strength bolts will pull the outer expansion sleeve 7 and the inner expansion sleeve 8 closer together axially. Since the contact surface between the inner expansion sleeve 8 and the outer expansion sleeve 7 is a conical surface, this axial movement will force the outer expansion sleeve 7 to expand outwards and simultaneously force the inner expansion sleeve 8 to contract inwards. The outer surface of the outer expansion sleeve 7 tightly grips the inner hole of the hub, and the inner surface of the inner expansion sleeve 8 tightly grips the outer circle of the torque sensor shaft 9. In this way, a huge contact pressure and static friction are generated between the torque sensor shaft 9, the inner expansion sleeve 8, the outer expansion sleeve 7, and the hub. This huge static friction is used to transmit torque, axial force, or combined load.

[0026] The expansion coupling structure, consisting of an inner expansion sleeve 8, an outer expansion sleeve 7, high-strength bolts, and nuts, improves positioning accuracy, eliminates the weakening effect of keyways on shaft strength and the clearance present in keyed connections, achieving extremely high concentricity between the shaft and hub, resulting in smooth transmission. It is particularly suitable for high-speed precision transmission. Furthermore, the absence of keyways on the shaft and hub avoids stress concentration at the keyway root, improving the fatigue strength of the shaft and hub, extending service life, and providing high connection strength and load-bearing capacity, capable of transmitting large torques, axial forces, and impact loads. Assembly and disassembly are simple, requiring only tightening or loosening of bolts, and the coupling is reusable. This is highly advantageous for equipment requiring frequent maintenance and parts replacement. Additionally, under extreme overload conditions, the expansion sleeve will slip, protecting other critical components on the main unit from damage. Moreover, shafts of the same inner diameter can be adapted to different torque requirements by selecting different expansion sleeve models, offering good versatility.

[0027] Specifically, such as Figure 1 and Figure 3 As shown, a head spacing adjustment assembly 6 is installed on the side wall of the head mount mounting flange 2. The head spacing adjustment assembly 6 includes a head mount 601, an adjusting slider 602, a slide rail 603, and a positioning bolt 604. The slide rail 603 is fixedly installed on the side wall of the head mount mounting flange 2. The adjusting slider 602 is slidably installed on the slide rail 603. The positioning bolt 604, which abuts against the end face of the slide rail 603, passes through the interior of the adjusting slider 602. The head mount 601 is fixedly installed on the side wall of the adjusting slider 602. The head mount 601 is fixedly connected to the head 5.

[0028] By adopting the above technical solution, the radial clearance adjustment is achieved through the read head spacing adjustment component 6 during use: after loosening the positioning bolt 604, the adjusting slider 602 can slide along the slide rail 603 fixed on the read head frame mounting flange 2, driving the read head frame 601 and the read head 5 to move synchronously until the gap between the read head 5 and the encoder 4 code disk reaches the design standard of 0.1-0.3mm. After tightening the positioning bolt 604, the end of the bolt abuts against the end face of the slide rail 603 to generate friction, locking the slider position to complete the calibration.

[0029] Working principle: In use, the adjusting washer 3 is placed on the end of the torque sensor shaft 9 near the torque sensor 1. Then, the inner expansion sleeve 8 and the outer expansion sleeve 7 are successively placed on the torque sensor shaft 9, so that the inner expansion sleeve 8 is in contact with the end face of the adjusting washer 3. The encoder 4 is fixedly installed on the front outer wall of the outer expansion sleeve 7, and the hub is placed on the outside of the outer expansion sleeve 7. Finally, the reading head frame mounting flange 2 is fixed by the stop of the torque sensor end cover 10, completing the initial alignment of the reading head 5 and the encoder 4. The outer expansion sleeve 7 and the inner expansion sleeve 8 are pulled closer axially by high-strength bolts and nuts. Since the contact surface of the two is a conical surface, the axial tension will be converted into radial pressure. The outer expansion sleeve 7 expands outward to hug the inner hole of the hub, and the inner expansion sleeve 8 contracts inward to hug the torque sensor shaft 9. Finally, a clearance-free interference fit is formed between the shaft, the expansion sleeve, and the hub, realizing the rigid transmission of torque. During this stage, the adjusting washer 3, through thickness compensation, initially calibrates the axial relative position of the encoder 4 and the reader 5 to ensure initial alignment accuracy. When the hub is driven to rotate by external force, the torque and speed are synchronously transmitted to the torque sensor shaft 9 through the rigid connection between the expansion sleeve 7 and the expansion inner sleeve 8. The strain gauge inside the torque sensor 1 senses the torsional deformation of the shaft and converts the mechanical torque into an electrical signal output to complete the torque measurement. At the same time, the encoder 4, fixed on the expansion sleeve 7, rotates synchronously with the shaft, and the reader 5 is fixed on the reader spacing adjustment assembly 6 through the reader frame 601, continuously collecting the photoelectric signal of the encoder 4 code disk. After signal processing, it is converted into angle or speed data to achieve synchronous measurement of angle and torque. Axial adjustment is achieved through the adjusting washer 3: if the axial misalignment between the encoder 4 and the reader 5 is found to be excessive during assembly or maintenance, the adjusting washer 3 of different thicknesses can be replaced to correct the axial relative position through thickness compensation. Radial clearance adjustment is achieved through the head spacing adjustment assembly 6: After loosening the positioning bolt 604, the adjusting slider 602 can slide along the slide rail 603 fixed on the head mounting flange 2, driving the head mounting 601 and the head 5 to move synchronously until the gap between the head and the encoder 4 code disk reaches the design standard, usually 0.1-0.3mm. After tightening the positioning bolt 604, the end of the bolt abuts against the end face of the slide rail 603 to generate friction, locking the slider position to complete the calibration.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A detection instrument integrating a high-precision angle encoder and a torque sensor, comprising a torque sensor (1), characterized in that: A torque sensor shaft (9) is installed in the middle of the torque sensor (1). An expansion inner sleeve (8) is fitted on one end of the torque sensor shaft (9). An expansion outer sleeve (7) is fitted on the outside of the expansion inner sleeve (8). An encoder (4) is fixedly installed on the front outer wall of the expansion outer sleeve (7). A reading head (5) is provided on one side of the encoder (4).

2. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 1, characterized in that: The torque sensor (1) is externally fixedly mounted with a torque sensor end cover (10), and a reading head frame mounting flange (2) is fixedly mounted at the stop of the torque sensor end cover (10).

3. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 2, characterized in that: The head spacing adjustment assembly (6) is installed on the side wall of the head mounting flange (2). The head spacing adjustment assembly (6) includes a head mount (601), an adjustment slider (602), a slide rail (603), and a positioning bolt (604).

4. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 3, characterized in that: The slide rail (603) is fixedly installed on the side wall of the reading head frame mounting flange (2). An adjusting slider (602) is slidably installed on the slide rail (603). A positioning bolt (604) that abuts against the end face of the slide rail (603) is provided inside the adjusting slider (602).

5. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 4, characterized in that: The reading head frame (601) is fixedly installed on the side wall of the adjusting slider (602), and the reading head frame (601) is fixedly connected to the reading head (5).

6. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 1, characterized in that: The expansion sleeve (7) and the expansion inner sleeve (8) are fixedly connected by high-strength bolts and nuts, and the contact surface between the expansion sleeve (7) and the expansion inner sleeve (8) is a conical surface.

7. The detection instrument integrating a high-precision angle encoder and a torque sensor according to claim 6, characterized in that: An adjusting washer (3) is provided at one end of the expansion sleeve (8) near the torque sensor (1), and the adjusting washer (3) is sleeved on the torque sensor shaft (9).

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