CN108593162A - Large Load Flexible Torque Sensor with Local Structure Reinforcement - Google Patents

Abstract

A large-load flexible torque sensor with local structure strengthening relates to a passive vibration-damping elastic element. The problem of traditional metal rubber moment sensor because stress concentration leads to moment sensor to bear the load ability little at straining roof beam and straining roof beam baffle intercommunication portion is solved. The outer ring comprises an annular outer ring substrate, an annular boss, two strain beams and four strain beam baffles, wherein the annular boss is arranged on one end face of the annular outer ring substrate; the connecting part is formed by the intersection parts of the strain beams and the strain beam baffles, and a convex edge is arranged on the connecting part in the axial direction and is in non-contact with the inner ring and the baffles. The invention is mainly applied to the robot joint.

Description

Large Load Flexible Torque Sensor with Local Structure Reinforcement

technical field

The invention relates to a passive vibration damping elastic element.

Background technique

With the development of robot technology, human-machine collaborative manipulators have received more and more attention. As an important part of human-machine collaborative manipulators, flexible joints have played an important role in ensuring human safety. The introduction of links also brings vibration to the system, which reduces the accuracy of robot joint position control. At present, active, semi-active and passive methods can be used to suppress vibration. Active vibration control uses control algorithms to reduce vibration, and its reliability is poor. Semi-active vibration control requires additional control components such as motors, which are bulky and complex in structure. In the passive control, metal rubber is used as the damping and shock-absorbing material, which has the advantages of long service life, large damping characteristics, and good vibration reduction effect. In addition, the torque can be measured by adding strain gauges at the connection.

However, the structural design of the traditional metal-rubber torque sensor CN 107671875 A is not reasonable enough, and the load bearing capacity of the torque sensor is small due to the stress concentration on the strain beam; the above problems need to be solved urgently.

Contents of the invention

The invention aims to solve the problem that the traditional metal rubber torque sensor has a small load bearing capacity due to the stress concentration on the connecting part of the strain beam and the strain beam baffle. The invention provides a large-load flexible torque sensor with local structure strengthening .

Large-load flexible torque sensor with local structural reinforcement, including inner ring, outer ring, four metal rubber pads and baffles,

The inner ring is fastened on the outer ring, and the four metal rubber pads are pre-compressed in the area enclosed by the inner ring and the outer ring after fastening, and the baffle cover is installed on the outer ring;

The outer ring includes an annular outer ring base plate, an annular boss, two strain beams, and four strain beam baffles. The annular boss is set on one end surface of the annular outer ring base plate, and the two strain beams are set on the inner wall of the annular outer ring base plate. , and each strain beam is provided with a strain beam baffle on the left and right sides, and strain gauges are installed on the strain beam;

The connecting portion formed by the intersection of the strain beam and the strain beam baffle, and the connecting portion is provided with a convex edge in the axial direction, and the convex edge is not in contact with the inner ring and the baffle.

Preferably, a reinforcing rib is provided between the annular outer ring base plate and the annular boss.

Preferably, the other end surface of the annular outer ring substrate on the outer ring is provided with a concave edge, and the inner ring is fastened on the concave edge of the outer ring.

Preferably, a positioning boss is provided on the baffle, and the positioning boss is fixedly connected to the inner ring.

Preferably, the annular inner ring substrate of the inner ring is provided with a first strain relief installation hole, and the baffle is provided with a second strain relief installation hole;

The first strain relief arrangement hole and the second strain relief arrangement hole are used for accommodating the protrusion together.

Preferably, the inner ring and the baffle are fixedly connected by bolts.

Preferably, each metal rubber pad is pre-compressed by 5°.

Preferably, there is a gap of at least 3 mm between the strain beam baffle and the inner wall of the annular outer ring base plate.

The beneficial effect brought by the present invention is that the present invention is provided with a convex edge on the connecting part formed by the intersecting part of the strain beam and the strain beam baffle, so that it can correspond to the strength of the intersecting part of the strain beam and the strain beam baffle, so that the torque sensor can Bearing greater torque, the bearing capacity is increased by 20%, the invention improves the contact condition between parts, the structure design is reasonable, and the rotation friction is reduced.

Description of drawings

Fig. 1 and Fig. 2 are the structure schematic diagrams of the large load flexible moment sensor of local structure strengthening of the present invention;

Figure 3 is an assembly drawing of the inner ring and the outer ring;

Figure 4 is an assembly drawing of the outer ring and the baffle.

Detailed ways

Specific Embodiment 1: Referring to Fig. 1 to Fig. 4 to illustrate this embodiment, the large-load flexible torque sensor with local structure strengthening described in this embodiment includes an inner ring 1, an outer ring 2, four metal rubber pads 3 and a baffle 4,

The inner ring 1 is fastened on the outer ring 2, and the four metal rubber pads 3 are pre-compressed in the area enclosed by the inner ring 1 and the outer ring 2, and the baffle plate 4 is installed on the outer ring 2;

The outer ring 2 includes an annular outer ring base plate 2-1, an annular boss 2-2, two strain beams 2-5, and four strain beam baffles 2-6, and the annular boss 2-2 is arranged on the annular outer ring base plate 2 -1 on one end face, two strain beams 2-5 are arranged on the inner wall of the annular outer ring substrate 2-1, and each strain beam 2-5 is provided with a strain beam baffle plate 2-6 on the left and right sides, And strain gages are installed on the strain beams 2-5;

The connecting portion formed by the intersection of the strain beam 2-5 and the strain beam baffle plate 2-6, and the connecting portion is provided with a convex edge 2-7 in the axial direction, and the convex edge 2-7 is connected to the inner ring 1 and the baffle plate 4 for non-contact.

In this embodiment, since the stress is concentrated on the strain beam 2-5, a convex edge 2-7 is provided on the strain beam 2-5 to ensure the strength of the strain beam 2-5, and the convex edge 2-7 is connected with the The inner ring 1 non-contact replaces the direct contact between the inner ring substrate and the strain beam baffle plate in the prior art to ensure the torque between the inner ring and the outer ring. This relationship is better reflected on the strain beams 2-5 to avoid unbalanced load and the influence of friction on the strain beam 3-5, the torque measurement accuracy is improved, and the measurement accuracy is increased by more than 20%.

Working principle: The input torque is transmitted to the strain beam 2-5 through the inner ring baffle 1-2, the metal rubber pad 3, and the strain beam baffle 2-6 on the outer ring 2, and the resistive type pasted on the strain beam 2-5 The strain gauge is deformed, and the degree of deformation of the strain gauge reflects the magnitude of the external moment.

Four strain beam baffles 2-6 are set on the outer ring 2 to facilitate the transfer of the pressure of the four metal rubber pads 3 to the strain beam 2-5, while preventing the strain on the metal rubber pad 3 and the strain beam 2-5. pieces in direct contact.

The connecting portion formed by the intersection of the strain beam 2-5 and the strain beam baffle plate 2-6, and the connecting portion is provided with a convex edge 2-7 in the axial direction. Through simulation analysis, it can be known that the inner ring 1 and the outer ring 2 are applied The position of the maximum stress after torque is the connection between the strain beam 2-5 and the strain beam baffle 2-6 (that is, the connection part). Compared with other structural strengthening methods: change the strain beam or the strain beam baffle 2-6 width and thickness, or make it have a certain slope, the present invention has the best effect of setting the convex edge 2-7 at the corresponding position of the strain beam, which can improve the bearing capacity of the whole torque sensor by about 20%, and simultaneously control the strain beam Stiffness has a negligible effect and is easy to manufacture.

The metal rubber pad 3 has elasticity and damping characteristics, and plays the role of position limiting and shock absorption.

Specific Embodiment 2: Referring to Fig. 1 to Fig. 4 to illustrate this embodiment, the difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in Specific Embodiment 1 is that the annular outer ring substrate 2-1 is connected with the annular convex A reinforcing rib 2-3 is provided between the platforms 2-2.

In this embodiment, the arrangement of the ribs 2 - 3 improves the bearing strength of the outer ring 2 .

Specific embodiment three: Referring to Fig. 1 to Fig. 4 to illustrate this embodiment, the difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in specific embodiment 1 or 2 is that the annular outer ring on the outer ring 2 The other end surface of the base plate 2-1 is provided with a concave edge 2-4, and the inner ring 1 is buckled on the concave edge 2-4 of the outer ring 2.

In this embodiment, the inner ring 1 is fastened on the concave edge 2-4 of the outer ring 2, which ensures the tight connection between the inner ring 1 and the outer ring 2, and limits the radial movement of the inner ring 1.

Specific Embodiment 4: Refer to Fig. 1 to Fig. 4 to illustrate this embodiment. The difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in Embodiment 1 or 2 is that the baffle plate 4 is provided with positioning protrusions. platform 4-1, and the positioning boss 4-1 is fixedly connected with the inner ring 1.

In this embodiment, the fixed connection between the positioning boss 4-1 and the inner ring 1 improves the stability of the entire torque sensor.

The baffle plate 4 is provided with a positioning boss 4-1, and the positioning boss 4-1 can improve the connection strength between the inner ring 1 and the baffle plate 4.

Embodiment 5: Refer to Fig. 1 to Fig. 4 to illustrate this embodiment. The difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in Embodiment 1 or 2 is that the annular inner ring substrate of the inner ring 1 1-1 is provided with a first strain convex edge installation hole 1-1-1, and the baffle plate 4 is provided with a second strain convex edge installation hole 4-2;

The first strain convex edge installation hole 1-1-1 and the second strain convex edge installation hole 4-2 are used for accommodating the convex edge 2-7 together.

In this embodiment, the first strain relief installation hole 1-1-1 on the annular inner ring substrate 1-1 and the second strain relief installation hole 4-2 on the baffle plate 4 are the outer ring 2 The rotation of the upper strain beam 2-5 leaves enough rotation space to ensure the torque between the inner ring 1 and the outer ring 2. This relationship is better reflected on the strain beam 2-5, avoiding unbalanced load and friction on the strain The interference of the beams 2-5 affects the measurement of the torque, which improves the measurement accuracy of the torque by more than 30%.

The baffle plate 4 is provided with a second strain convex edge placement hole 4-2, leaving enough rotation space for the rotation of the outer ring 2, and also leaving space for the connection of the strain gauges.

The baffle 1-2 of the inner ring is in contact with the inner wall of the outer ring, and the baffle 4 is in contact with the strain beam 2-5, thereby restricting the axial movement between the inner ring 1 and the outer ring 2, the axial contact area is small, and the rotation can be reduced time friction.

Specific Embodiment 6: Referring to Fig. 1 to Fig. 4 to illustrate this embodiment, the difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in Embodiment 1 is that the inner ring 1 and the baffle 4 pass through Bolted connection.

Specific Embodiment 7: Refer to Fig. 1 to Fig. 4 to illustrate this embodiment. The difference between this embodiment and the large-load flexible moment sensor with local structural reinforcement described in Embodiment 1 or 2 is that each metal rubber pad 3 is pre-compressed 5°.

The metal rubber pad 3 of the present invention is pre-compressed at a certain angle, so that the characteristic curve of the torque rotation angle measured by the torque sensor can change continuously when the joint is forward and reverse, ensuring the accuracy near the zero position of the rotation angle.

The entire force sensor of the present invention can rotate within the range of plus or minus 5°. After the metal rubber pad 3 is assembled, each metal rubber pad 3 is pre-compressed by 5°, that is: when the inner ring 1 and the outer ring 2 are opposite When the rotation angle is 0°, that is, when there is no external torque, each metal rubber pad 3 is pre-compressed by 5°; when the relative rotation angle between the inner ring 1 and the outer ring 2 is 5°, the metal rubber pads on one side of each strain beam 2-5 3 is compressed by 10°, and the metal rubber pad 3 on the other side is compressed by 0°, so that the four metal rubber pads 3 are always in a compressed state, so that the torque-rotation angle characteristic curve measured by the torque sensor can be continuous when the joint is reversing changes while preventing the joints from wobbling under low loads.

Embodiment 8: Refer to FIGS. 1 to 4 to illustrate this embodiment. The difference between this embodiment and the large-load flexible moment sensor with local structure strengthening described in Embodiment 1 or 2 is that the strain beam baffle 2-6 is connected to the A gap of at least 3mm is left between the inner walls of the annular outer ring base plate 2-1.

In this embodiment, there is a gap of at least 3 mm between the strain beam baffle plate 2-6 and the inner wall of the annular outer ring substrate 2-1. It is convenient for milling and prevents expensive processing methods such as wire cutting from being too small.

Verification test: For a strain beam with a width of 10mm, the material is high-strength 7075 aluminum alloy, and a torque of 70NM is applied. The maximum stress of the ordinary torque sensor is 395MPa, and the maximum stress of the torque sensor with convex edges 2-7 is set on the strain beam in the present invention. 330MPa. Ordinary torque sensors reach a yield strength of 503 MPa when loaded with a load of 90 NM, but the torque sensor with convex edges 2-7 on the strain beam of the present invention reaches a yield strength of 503 MPa when loaded with a load of 108 NM.

The structure of the large-load flexible moment sensor with local structure strengthening in the present invention is not limited to the specific structures described in the above-mentioned embodiments, but may also be a reasonable combination of the technical features described in the above-mentioned embodiments.

Claims (8)

1. Large-load flexible torque sensor with local structure strengthening, including inner ring (1), outer ring (2), four metal rubber pads (3) and baffle (4), The inner ring (1) is fastened on the outer ring (2), and the four metal rubber pads (3) are pre-compressed in the area space enclosed by the inner ring (1) and the outer ring (2) after fastening, and the baffle ( 4) The cover is mounted on the outer ring (2); The outer ring (2) includes an annular outer ring base plate (2-1), an annular boss (2-2), two strain beams (2-5), four strain beam baffles (2-6), and an annular boss (2-2) is arranged on an end face of the annular outer ring substrate (2-1), two strain beams (2-5) are arranged on the inner wall of the annular outer ring substrate (2-1), and each strain beam ( A strain beam baffle (2-6) is provided on the left and right sides of 2-5), and strain gauges are installed on the strain beam (2-5); It is characterized in that the connecting portion formed by the intersection of the strain beam (2-5) and the strain beam baffle plate (2-6), and the connecting portion is provided with a convex edge (2-7) in the axial direction, and the convex edge (2-7) -7) It is not in contact with the inner ring (1) and the baffle (4). 2. The large-load flexible torque sensor with local structure strengthening according to claim 1, characterized in that, a reinforcing rib (2-2) is provided between the annular outer ring substrate (2-1) and the annular boss (2-2) 3). 3. The large-load flexible moment sensor with local structure strengthening according to claim 1 or 2, characterized in that, the other end surface of the annular outer ring substrate (2-1) on the outer ring (2) is provided with a concave edge (2-4), the inner ring (1) is fastened on the concave edge (2-4) of the outer ring (2). 4. The large-load flexible torque sensor with local structure strengthening according to claim 1 or 2, characterized in that, the baffle plate (4) is provided with a positioning boss (4-1), and the positioning boss (4-1 ) is fixedly connected with the inner ring (1). 5. The large-load flexible moment sensor with local structure strengthening according to claim 1 or 2, characterized in that, the annular inner ring substrate (1-1) of the inner ring (1) is provided with a first strain convex edge placement hole (1-1-1), and the baffle plate (4) is provided with a second strain convex edge placement hole (4-2); The first strain convex edge installation hole (1-1-1) and the second strain convex edge installation hole (4-2) are used for accommodating the convex edge (2-7) together. 6. The large-load flexible moment sensor with local structure strengthening according to claim 1, characterized in that, the inner ring (1) and the baffle (4) are fixedly connected by bolts. 7. The large-load flexible moment sensor with local structure strengthening according to claim 1, characterized in that each metal rubber pad (3) is pre-compressed by 5°. 8. The large-load flexible torque sensor with local structure strengthening according to claim 1, characterized in that, there is at least 3mm of space between the strain beam baffle plate (2-6) and the inner wall of the annular outer ring substrate (2-1). gap.