A functional bucket tooth assembly for excavators capable of measuring stress

Abstract

This invention specifically relates to a force-measuring excavator bucket tooth assembly, solving the problems of high soil penetration resistance and difficulty in disassembly and reassembly when the existing bucket tooth assemblies break. The force-measuring excavator bucket tooth assembly includes a mounting groove at the bottom of the connecting seat, with a flexible pressure sensor fixed inside the groove. A connector is located at the left end of the connecting seat, and the connector is connected to the bucket tooth via two mounting pins. The bucket tooth includes curved ridges, with sliding portions on both sides of the curved ridges, and a cutting portion at the left end of the sliding portions. In this invention, the bucket tooth includes a curved ridge structure that reduces soil penetration resistance; when the bucket tooth is subjected to force, causing deformation of the hollow cylindrical pins, the capacitance value of the flexible pressure sensor changes, thus measuring the force on the bucket tooth.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, specifically to a functional bucket tooth assembly for excavators that can measure force. Background Technology

[0002] The bucket is the excavating component of an excavator that performs digging and loading functions during operation. The bucket consists of the bucket body and the bucket tooth assembly. The bucket tooth assembly, located at the end of the excavator bucket, is a crucial and frequently worn part. There are two types of bucket tooth assemblies: a one-piece structure and a segmented structure. The one-piece structure is difficult to forge, while the segmented structure, consisting of a connecting seat and the bucket teeth, is easier to forge and allows for convenient replacement when wear or breakage occurs.

[0003] The bucket teeth are located at the very front of the bucket and wedge into the soil at a certain angle during operation. The performance of the bucket teeth directly affects the digging performance of the excavator bucket and even the excavator itself. Reducing the resistance encountered by the bucket teeth when entering the soil can effectively improve the digging efficiency of the excavator. From a biomimetic perspective, the pangolin, a soil animal, has evolved excellent claw and toe structures in the process of burrowing and foraging. This study focuses on the third toe of the pangolin's forepaw. The third toe of the pangolin's forepaw is the first to contact the soil during digging, playing a major role in penetration, breaking through the soil, and digging. The outer side of the pangolin's third toe is a rounded surface, while the inner side is a concave curved surface with an upward-curving edge, exhibiting a ridge structure that gradually extends from the toe tip to the toe root. The research results show that during the process of pangolin claws entering the soil, the outer contour of the claws bears most of the resistance, which is similar to the process of burrowing into the soil with teeth. During the excavation process, the inner convex structure of the claws, which is similar to a cutting edge, interacts with the soil, creating a gap between the soil and the inner structure. This effectively prevents the soil from being compacted on the surface of the claws. During the excavation process, the soil and the convex surface slide relative to each other, thereby further reducing the resistance during excavation.

[0004] Therefore, it is necessary to invent a force-measuring excavator bucket tooth assembly to solve the problems of high soil penetration resistance and difficulty in disassembly and reassembly when the existing bucket tooth assembly breaks. Simultaneously, a sensor force-measuring structure is added to the bucket tooth assembly to measure the force applied to the teeth. This invention includes a curved convex ridge structure with soil penetration resistance reduction function, an easy-to-disassemble mounting pin, and a bucket tooth force-measuring structure. This invention adopts a segmented structure, inspired by the claw structure and digging characteristics of pangolins. Addressing the problem of high resistance during soil penetration that easily leads to bucket tooth breakage, this invention designs a bucket tooth with drag-reducing function. Addressing the problem that most existing bucket tooth assemblies use cylindrical pins to connect the connecting seat and the bucket tooth, making disassembly and reassembly difficult when the bucket tooth needs replacement, this invention designs an easy-to-disassemble mounting pin to connect the bucket tooth and the connecting seat. When the bucket tooth is subjected to external force, the force is transmitted and acts on the connecting seat. In this invention, a flexible pressure sensor serves as the bucket tooth force-measuring structure to measure the magnitude of the force applied to the bucket tooth. Summary of the Invention

[0005] In order to solve the problems of high soil penetration resistance and difficulty in disassembly and reassembly when the existing bucket tooth assembly breaks, the present invention provides a functional excavator bucket tooth assembly with measurable force.

[0006] This invention is achieved using the following technical solution:

[0007] A force-measuring excavator bucket tooth assembly includes bucket teeth and a connecting seat; the connecting seat is a U-shaped groove with an opening facing right, the end of the bucket body is embedded in the inner cavity of the connecting seat, and the connecting seat and the bucket body are detachably connected by a pin mechanism passing through them; a through mounting groove is provided at the bottom of the groove of the connecting seat, and a flexible pressure sensor in contact with the bucket body is fixed in the inner cavity of the mounting groove.

[0008] The left end of the connecting seat is provided with a connecting head that is embedded in the right side of the bucket tooth. The connecting head and the bucket tooth are detachably connected by two mounting pins that are distributed front and rear and arranged opposite to each other. The opposite ends of the two mounting pins are threaded to the connecting head.

[0009] The bucket teeth include a curved protrusion located in the middle and arranged laterally. The front and rear sides of the curved protrusion are integrally provided with a sliding part with a concave curved upper surface. The left end of the sliding part is integrally provided with a cutting part with a lower left and higher right and a flat upper surface. The two sliding parts and the two cutting parts are symmetrically arranged front and back.

[0010] In this invention, the upper surface of the sliding part is curved, and the curvature of the curved surface decreases from top to bottom.

[0011] In this invention, the right surface of the bucket tooth is provided with a groove structure that matches the shape of the connector, and the front and rear sides of the groove structure are provided with conical holes that communicate with it for the installation pin to pass through.

[0012] The present invention provides an installation groove on the inner wall of the arc-shaped curved surface where the connecting seat contacts the bucket body for installing a flexible pressure sensor, thereby achieving the purpose of monitoring the force on the bucket teeth.

[0013] Furthermore, the width of the curved convex ridge along the longitudinal direction is 18mm-22mm; the curve equation corresponding to the intersection line between the upper surface of the curved convex ridge and the transverse vertical surface is shown in formula (a):

[0014] y = -0.0013x 2 -0.0098x+77.53 (a)

[0015] The x-value of the intersecting line is 0mm-240.5mm, and the corresponding y-value is 77.53mm-0mm.

[0016] To achieve a smaller entry angle, making it easier for the bucket teeth to wedge into the soil, and to minimize the resistance experienced by the bucket teeth during the entry process, this invention uses EDEM discrete element simulation software to simulate and compare bucket tooth models constructed with different curve equations, ultimately obtaining the optimized curve equation shown in formula (a).

[0017] As attached Figure 10 As shown, a rectangular coordinate system is established, with the intersection point O of the x-axis and y-axis as the origin. The equation of the curve has x values ​​ranging from 0 mm to 240.5 mm, and the corresponding y values ​​ranging from 77.53 mm to 0 mm. This curve segment is selected as the convex edge curve of the surface. To achieve higher strength for the convex edge, the width of the middle edge of the bucket tooth is 18 mm to 22 mm, with inwardly concave curved surfaces on both sides. This bucket tooth has the function of reducing the resistance to soil penetration.

[0018] Furthermore, the left and right surfaces of the bucket teeth are both longitudinal vertical surfaces; the left part of the front surface of the bucket teeth is a left-rear-right-front oblique vertical surface, and the right part of the front surface is a transverse vertical surface; the left part of the rear surface of the bucket teeth is a left-front-right-rear oblique vertical surface, and the right part of the rear surface is a transverse vertical surface; a reinforcing part is integrally provided on the upper right side of both sliding parts, and the reinforcing part on the front side protrudes forward and upward, and the reinforcing part on the rear side protrudes backward and upward; the bucket teeth also include a longitudinally vertical D-shaped connecting block located at the right end, and a triangular block with a planar upper surface located on the inner side and a C-shaped irregular block located on the outer side are connected to the two reinforcing parts and the connecting block.

[0019] Furthermore, the number of the pin mechanisms is two distributed from left to right, and each pin mechanism includes a hollow cylindrical pin that passes vertically through the connecting seat and the bucket body and a rubber cylindrical plug that passes through the middle of the hollow cylindrical pin.

[0020] Most currently disclosed connection methods between the connecting seat and the bucket body use cylindrical pins. This connection method can withstand large loads and can operate in relatively harsh working environments. According to available data, the maximum force on a single bucket tooth of a conventional excavator during operation is approximately 30 kN. This invention uses a hollow cylindrical pin to connect the bucket body and the connecting seat. This hollow cylindrical pin can maximize the relative positional changes between the connecting seat and the bucket body without causing plastic deformation and ensuring the normal operation of the bucket tooth assembly, thereby enabling the monitoring of the force on the bucket tooth.

[0021] The rubber plunger prevents foreign objects from entering the hollow cylindrical pin during operation.

[0022] During the operation of the excavator, the hollow cylindrical pin is subjected to shear force. Therefore, the maximum shear force that it can withstand is checked using formula (b).

[0023]

[0024] In the formula, I is the shear stress, MPa; Q is the force on the cross section, N; and A is the cross-sectional area, mm². 2 [I] represents the allowable shear stress, in MPa;

[0025] The hollow cylindrical pin is made of 304 stainless steel, with a yield strength greater than or equal to 205 MPa. 304 stainless steel is a ductile material. According to research, the allowable shear stress for ductile materials is approximately 0.6 to 0.8 times the yield stress. Therefore, the allowable shear stress for 304 stainless steel is taken as 164 MPa. Calculations are performed based on the above data and formulas:

[0026] Q≤A×[I]=3.14×(10 2 -6 2 )×164≈32957N

[0027] Therefore, the maximum shear stress that the hollow cylindrical pin can withstand is 32597N. The connecting seat uses two hollow cylindrical pins to connect the connecting seat and the bucket body, so it can withstand a maximum shear force of 64914N, which is much greater than the load it experiences during normal operation. Therefore, this connection method can be used for the connection of bucket tooth assemblies.

[0028] Furthermore, both mounting pins include a tapered post on the outer side and a threaded post on the inner side that engages with the internal threaded hole of the connector. The diameter of the threaded post is smaller than the diameter of the tapered post, and the outer end face of the tapered post has an internal hexagon countersunk hole.

[0029] In existing bucket tooth assemblies, the connection between the bucket teeth and the connecting seat generally uses a through cylindrical pin. This connection method is relatively complex to install, and it is difficult to disassemble and reassemble if the bucket teeth break. Based on these reasons, this invention designs a novel connection method using two sections of a new type of tapered pin. This new tapered pin has the function of easy disassembly and assembly. There is a threaded relief groove structure between the threaded column and the tapered column, and all other sharp parts are chamfered.

[0030] The internal hex countersunk hole allows for easy rotation and installation of the mounting pin using an external hex wrench, further enhancing the ease of operation during installation.

[0031] Furthermore, the upper plate of the connecting seat and the lower plate of the connecting seat are both provided with dovetail grooves located in the middle and arranged laterally. The bucket body is integrally provided with a dovetail-shaped locking block that matches the position of the dovetail groove. The bottom of the dovetail groove is provided with an installation groove I located near the side of the bucket body and communicating with the end of the connecting seat. The lower surface of the dovetail-shaped locking block located on the lower side of the bucket body is provided with a wire receiving groove that runs through the left and right sides.

[0032] Because hollow cylindrical pins have lower strength compared to traditional cylindrical pins, this invention designs a slide rail structure on the connecting seat to reduce the load on the hollow cylindrical pin during operation. Dovetail grooves and dovetail-shaped blocks are provided on both the upper and lower surfaces of the connecting seat that fit against the bucket body, with the dovetail grooves positioned at the center along the longitudinal direction. Through the structural design of the dovetail grooves and dovetail-shaped blocks, the movement of the connecting seat in the longitudinal direction perpendicular to the direction of the dovetail grooves and dovetail-shaped blocks can be restricted, thereby distributing the load on the hollow cylindrical pin.

[0033] Further, the length of the mounting pin is j, and the value of j ranges from 44mm to 48mm; the taper of the tapered column is 1:50, the length along the longitudinal direction is g, and the value of g ranges from 34mm to 36mm; the diameter of the large end of the tapered column is f, and the value of f ranges from 18mm to 22mm; the inner diameter of the internal hexagon countersunk hole is 12mm, and the countersunk depth is 10mm; the length of the threaded column is h, and the value of h ranges from 8mm to 10mm; the external thread type of the threaded column is M10; the connector is a square connector with a width of k along the longitudinal direction, and k is 60mm; the middle of the connector has a front and rear opening. The mounting hole is a through-hole that is symmetrical front and back. The middle part of the mounting hole is an M10 internal thread hole with a length of i, and the two ends are conical holes with a taper of 1:50, and the value of i ranges from 26mm to 30mm. The hollow cylindrical pin is made of 304 stainless steel, and its outer diameter is 20mm, inner diameter is 12mm, and length is 85mm. The diameter of the rubber cylindrical plug is 12mm and its length is 85mm. The depth of the dovetail groove is n, and the value of n ranges from 6mm to 8mm. The dovetail groove has a symmetrical structure front and back, and its maximum width along the longitudinal direction is m, and the value of m ranges from 45mm to 55mm. The inclination angle of the two groove walls of the dovetail groove is 60°.

[0034] Furthermore, the flexible pressure sensor is a capacitive flexible pressure sensor; the bottom of the groove of the connecting seat and the bottom of the groove of the mounting groove are both arc-shaped. In order to reduce stress concentration, the pressure-bearing surface in contact with the bucket body is an arc-shaped curved surface. It is impossible to place a rigid sensor on the arc-shaped curved surface for measurement. The flexible sensor can be applied to the arc-shaped curved surface for measurement. Therefore, the present invention uses a flexible pressure sensor to measure the force on the bucket teeth.

[0035] Furthermore, the method for fabricating the flexible pressure sensor is implemented using the following steps:

[0036] Step S1: Use a piece of silver-plated fiber knitted fabric with a thickness of 0.2mm, a length of 80mm, and a width of 10mm as the first electrode plate of the sensor. Pour 5 grams of the stirred Ecoflex liquid onto the first electrode plate and use an automatic coating machine to adjust the thickness of the Ecoflex liquid to 0.2mm.

[0037] Step S2: Place the first electrode plate coated with Ecoflex liquid into a drying oven and dry it at 80 degrees Celsius for two minutes, then remove it; then use another piece of silver-plated fiber knitted fabric with the same shape as the first electrode plate as the second electrode plate of the sensor, and cover the second electrode plate on the uncured Ecoflex liquid, thereby obtaining a semi-finished product of capacitive flexible pressure sensor, and place the semi-finished product of capacitive flexible pressure sensor into a drying oven at 80 degrees Celsius until it is completely dried; then cut the cured Ecoflex so that the cured Ecoflex is the same size as the first electrode plate and the second electrode plate.

[0038] Step S3: Take out the cut capacitive flexible pressure sensor semi-finished product and connect a wire to each of the first and second plates using conductive silver paste;

[0039] Step S4: Encapsulation of the sensor: Pour 5 grams of stirred PDMS liquid onto a rigid substrate. Use an automatic coating machine to coat the PDMS liquid to a thickness of 0.05 mm. Place the rigid substrate with the PDMS liquid attached into an 80°C drying oven until completely dry. After drying, remove the substrate and peel the cured PDMS off the rigid substrate. Use a tool to cut the cured PDMS into PDMS cured blocks with a length of 90 mm, a width of 20 mm, and a thickness of 0.05 mm. Repeat this process to obtain two PDMS cured blocks with a length of 90 mm, a width of 20 mm, and a thickness of 0.05 mm. Then, use silicone rubber to adhere the two PDMS cured blocks to the opposite surfaces of the first and second electrodes, respectively. This completes the encapsulation of the sensor, resulting in a finished capacitive flexible pressure sensor.

[0040] The attached diagram shows the bucket tooth assembly in its assembled state with the bucket body. Figure 2 As shown in the attached diagram, a cross-sectional view of the connection between the connecting seat and the bucket body is also included. Figure 3 As shown, the measurement principle is as follows: When the bucket teeth are subjected to digging resistance in the right direction, the upper and lower parts of the hollow cylindrical pin that are in contact with the connecting seat experience strain in the right direction, as shown in the attached figure. Figure 15 As shown, when the excavation resistance ranges from 0N to 4000N, the corresponding strain range is 0μm to 30μm. The connecting seat shifts to the right, causing the flexible sensor to be compressed. This reduces the distance between the first and second plates, resulting in a change in capacitance. (See attached diagram.) Figure 16 As shown, the capacitance value increased from 105pF to 122.5pF. By calibrating the relationship between digging resistance, strain, and capacitance, the digging resistance of the bucket teeth was finally measured.

[0041] The structural diagram of the connector is attached. Figure 4As shown, the lower plate of the connector has a mounting groove I at its far end for housing the power supply module and wireless transmission module of the capacitive flexible pressure sensor. There is a threaded hole on each side of mounting groove I. After the power supply module and wireless transmission module are placed, they are encapsulated with a wear-resistant polymer plastic plate and secured with screws on both sides. A partial magnified view of the bucket assembly viewed from the bottom upwards (hidden lines are visible) is attached. Figure 5 As shown, a wire receiving groove is formed on the dovetail-shaped block on the lower surface of the bucket body. The wire of the capacitive flexible pressure sensor located at the mounting slot is connected to the mounting slot I through the wire receiving groove to realize the measurement of the force on the bucket teeth and the transmission of signals. Here, the power supply module and the wireless transmission module adopt existing known structures.

[0042] This invention addresses the problems of high soil penetration resistance and difficulty in disassembly when the bucket teeth assembly breaks by designing the shape of the bucket teeth and the structure of the bucket teeth assembly in existing buckets, and uses a flexible pressure sensor to measure the force on the bucket teeth.

[0043] In this invention, the bucket teeth are modeled after the curved surface contour of a pangolin's claws and toes, and include a curved convex ridge structure that reduces soil penetration resistance. The bucket teeth and connecting seat are connected using a novel mounting pin, which is easy to install and remove. The connecting seat and bucket body are connected using two hollow cylindrical pins, a dovetail groove, and a dovetail-shaped locking block. The arc-shaped surface of the connecting seat in contact with the bucket body has a mounting groove for installing a flexible pressure sensor. During installation, the flexible pressure sensor is positioned so that it is in direct contact with the bucket body. When the bucket teeth are subjected to force, causing the hollow cylindrical pins to deform, the capacitance value of the flexible pressure sensor changes, thus allowing for the measurement of the force on the bucket teeth. This invention includes bucket teeth with a curved convex ridge structure that reduces soil penetration resistance, a mounting pin that is easy to install and remove, and a bucket tooth force-measuring structure.

[0044] To verify the above-mentioned beneficial effects, the following comparative experiment was conducted:

[0045] Comparative Experiment 1:

[0046] This flexible pressure sensor is mainly used for detecting the force on bucket teeth. It monitors the change in the relative position between the connecting seat and the bucket body caused by the elastic deformation of the hollow cylindrical pins due to shear force, thus achieving force monitoring of the bucket teeth. This experiment used Ansys WorkBench finite element simulation software to simulate and analyze the deformation of a pair of hollow cylindrical pins under total forces of 5000N, 10000N, 15000N, 20000N, 25000N, 30000N, 35000N, and 40000N. The deformation trend of the contact area between the hollow cylindrical pins and the connecting seat with digging resistance is shown in the attached figure. Figure 15As shown, the strain range is 0μm-30μm. When strain occurs at the contact point between the hollow cylindrical pin and the connecting seat, it compresses the flexible pressure sensor, causing a corresponding change in the distance between the first and second plates of the flexible pressure sensor. The Maxwell capacitance value of the flexible pressure sensor under different deformation conditions was simulated using COMSOL Multiphysics simulation software. Under a strain range of 0μm-30μm, the capacitance value of the flexible pressure sensor varies from 105PF to 122.5PF. The trend of capacitance value change of the flexible pressure sensor with varying digging resistance is shown in the attached figure. Figure 16 As shown, the digging resistance of the bucket teeth was finally measured by calibrating the relationship between digging resistance, strain, and capacitance.

[0047] Comparative Experiment 2:

[0048] To verify the drag reduction performance of the bucket teeth (i.e., biomimetic bucket teeth) in this invention, a conventional bucket tooth without curved edges was designed for comparative experiments. The longitudinal width of the curved protrusions of the biomimetic bucket tooth model used for the comparative experiment was 20 mm. Discrete element simulation was performed using EDEM software for comparison. After derivation and calculation, to minimize the simulation computation while maximizing the accuracy of the simulation results, a soil trough with a length of 400 mm, a width of 300 mm, and a height of 300 mm was constructed. 130,000 soil particles with a diameter of 5 mm were generated in the trough and allowed to settle for a period of time. The conventional bucket tooth model and the biomimetic bucket tooth model were then imported into the trough, with both models positioned as close as possible to the soil trough to reduce the computational load. The EDEM simulation models are attached. Figure 17 With appendix Figure 18 As shown, the rotation center is an axis 600mm directly above the center of the bucket tooth and perpendicular to the screen direction. The rotational speed is 1 rad / s, and the total simulation time is 1 second. The simulation is performed after saving the parameters. The data comparison chart of the simulation results is attached. Figure 19 As shown in the figure, the average force on both types of bucket teeth is basically the same from 0s to 0.25s. This is because the protrusion of the curved surface ridges of the bionic bucket teeth is smaller during this stage. From 0.25s to 0.4s, the part of the curved surface ridges of the bionic bucket teeth with larger protrusions enters the soil. At this time, the average resistance experienced by the bionic bucket teeth is significantly less than that of ordinary bucket teeth. The data fluctuates more significantly from 0.4s to 0.5s, but the average force on both types of bucket teeth is basically the same. This is because there are reinforcing parts on both sides of the curved surface ridges of the bionic bucket teeth, which increases the resistance. The force on the bucket teeth after 0.5s is not of reference value. The simulation results above show that the curved surface ridges of the bionic bucket teeth have a drag-reducing function. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of the present invention;

[0050] Figure 2 This is a reference diagram showing the state of the present invention when it is assembled into the bucket body;

[0051] Figure 3 This is a cross-sectional schematic diagram of the connection between the connecting seat and the bucket body in this invention;

[0052] Figure 4 This is a schematic diagram of the connecting seat in this invention;

[0053] Figure 5 This is a partially enlarged view of the bucket assembly in this invention, viewed from the bottom upwards (hidden lines are visible);

[0054] Figure 6 This is a cross-sectional schematic diagram of the connecting seat in this invention;

[0055] Figure 7 This is a schematic diagram of the structure of the bucket teeth in this invention;

[0056] Figure 8 This is a schematic diagram of the structure of the bucket teeth after the soil-cutting part is removed in this invention;

[0057] Figure 9 This is a schematic diagram of the structure of the bucket teeth after the soil-cutting and soil-sliding parts are removed in this invention;

[0058] Figure 10 This is a schematic diagram of the curved surface of the convex edge in this invention;

[0059] Figure 11 This is a cross-sectional schematic diagram of the connection between the bucket teeth and the connector in this invention;

[0060] Figure 12 This is a cross-sectional schematic diagram of the connector in this invention;

[0061] Figure 13 This is a schematic diagram of the installation pin in this invention;

[0062] Figure 14 This is a side view of the mounting pin in this invention;

[0063] Figure 15 This is a diagram showing the deformation trend of the contact portion between the hollow cylindrical pin and the connecting seat in the first comparative experiment of this invention as the excavation resistance changes.

[0064] Figure 16 This is a graph showing the trend of capacitance change of the flexible pressure sensor as the excavation resistance changes in Comparative Experiment 1 of this invention.

[0065] Figure 17 This is the EDEM simulation model of the biomimetic bucket teeth in Comparative Experiment 2 of this invention;

[0066] Figure 18This is the EDEM simulation model of ordinary bucket teeth in Comparative Experiment 2 of this invention;

[0067] Figure 19 This is a data comparison chart of the simulation results of two types of bucket teeth in Comparative Experiment 2 of this invention.

[0068] In the diagram, 1-bucket tooth, 2-connecting seat, 3-bucket body, 4-mounting groove, 5-flexible pressure sensor, 6-connector, 7-mounting pin, 8-curved convex ridge, 9-slippery part, 10-soil cutting part, 11-wire receiving groove, 12-mounting groove I, 13-reinforcing part, 14-connecting block, 15-triangular block, 16-irregular block, 17-hollow cylindrical pin, 18-rubber cylindrical plug, 19-conical column, 20-threaded column, 21-internal hexagon countersunk hole, 22-dovetail groove, 23-mounting hole, 24-dovetail-shaped locking block, 25-hollow cylindrical pin mounting hole. Detailed Implementation

[0069] Example 1

[0070] A force-measuring excavator bucket tooth assembly, as shown in the attached figure. Figure 1 Appendix Figure 2 Appendix Figure 3 As shown, it includes a bucket tooth 1 and a connecting seat 2; the connecting seat 2 is a U-shaped groove with the opening facing right, the end of the bucket body 3 is embedded in the inner cavity of the connecting seat 2, and the connecting seat 2 and the bucket body 3 are detachably connected by a pin mechanism passing through them; a through mounting groove 4 is provided at the bottom of the groove of the connecting seat 2, and a flexible pressure sensor 5 that contacts the bucket body 3 is fixed in the inner cavity of the mounting groove 4.

[0071] The left end of the connecting seat 2 is provided with a connecting head 6 that is embedded in the right part of the bucket tooth 1. The connecting head 6 and the bucket tooth 1 are detachably connected by two mounting pins 7 that are distributed front and rear and arranged opposite to each other. The opposite ends of the two mounting pins 7 are threaded to the connecting head 6.

[0072] As attached Figure 7 Appendix Figure 8 Appendix Figure 9 Appendix Figure 10 As shown, the bucket tooth 1 includes a curved protrusion 8 located in the middle and arranged in the transverse direction. The front and rear sides of the curved protrusion 8 are integrally provided with a sliding part 9 with a concave curved upper surface. The left end of the sliding part 9 is integrally provided with a cutting part 10 with a left lower and right higher upper surface and a planar upper surface. The two sliding parts 9 and the two cutting parts 10 are symmetrically arranged front and back.

[0073] As attached Figure 10 As shown, the width of the curved protrusion 8 along the longitudinal direction is 18mm; the curve equation corresponding to the intersection line between the upper surface of the curved protrusion 8 and the transverse vertical surface is shown in formula (a):

[0074] y = -0.0013x 2 -0.0098x+77.53 (a)

[0075] The x-value of the intersecting line is 0mm-240.5mm, and the corresponding y-value is 77.53mm-0mm.

[0076] As attached Figure 7 Appendix Figure 10 As shown, the left and right surfaces of the bucket tooth 1 are both longitudinal vertical surfaces; the left part of the front surface of the bucket tooth 1 is a left-rear-right-front oblique vertical surface, and the right part of the front surface is a transverse vertical surface; the left part of the rear surface of the bucket tooth 1 is a left-front-right-rear oblique vertical surface, and the right part of the rear surface is a transverse vertical surface; a reinforcing part 13 is integrally provided on the upper right side of each of the two sliding parts 9, and the reinforcing part 13 on the front side protrudes forward and upward, and the reinforcing part 13 on the rear side protrudes backward and upward; the bucket tooth 1 also includes a longitudinally vertical D-shaped connecting block 14 located at the right end, and a triangular block 15 located on the inner side with a planar upper surface and an irregular block 16 located on the outer side with a C-shaped upper surface are connected between the two reinforcing parts 13 and the connecting block 14.

[0077] As attached Figure 1 Appendix Figure 2 Appendix Figure 3 As shown, there are two pin mechanisms distributed from left to right. Each pin mechanism includes a hollow cylindrical pin 17 that passes vertically through the connecting seat 2 and the bucket body 3, and a rubber cylindrical plug 18 that passes through the middle of the hollow cylindrical pin 17.

[0078] As attached Figure 11 Appendix Figure 12 Appendix Figure 13 Appendix Figure 14 As shown, both mounting pins 7 include a tapered post 19 located on the outer side and a threaded post 20 located on the inner side that is threaded into the internal threaded hole of the connector 6. The diameter of the threaded post 20 is smaller than the diameter of the tapered post 19. The outer end face of the tapered post 19 is provided with an internal hexagon countersunk hole 21.

[0079] As attached Figure 3 Appendix Figure 4 Appendix Figure 5 Appendix Figure 6 As shown, the upper plate of the connecting seat 2 has a dovetail groove 22 located in the middle and arranged laterally on the lower surface and the upper surface of the lower plate. The bucket body 3 is integrally provided with a dovetail-shaped locking block 24 that matches the position of the dovetail groove 22. The bottom of the dovetail groove 22 has an installation groove I12 located near the side of the bucket body 3 and communicating with the end of the connecting seat 2. The lower surface of the dovetail-shaped locking block 24 located on the lower side of the bucket body 3 has a wire receiving groove 11 that runs through the left and right sides.

[0080] The length of the mounting pin 7 is j, and j is 44mm; the taper of the tapered column 19 is 1:50, the longitudinal length is g, and g is 34mm; the diameter of the large end of the tapered column 19 is f, and f is 18mm; the inner diameter of the internal hexagon countersunk hole 21 is 12mm, and the countersunk depth is 10mm; the length of the threaded column 20 is h, and h is 8mm; the external thread type of the threaded column 20 is M10; the connector 6 is a square connector with a longitudinal width of k, and k is 60mm; the connector 6 has a through-hole that is symmetrical from front to back in the middle. Mounting hole 23 has an M10 internal threaded hole of length i in the middle and conical holes with a taper of 1:50 at both ends, where i is 26mm. The hollow cylindrical pin 17 is made of 304 stainless steel and has an outer diameter of 20mm, an inner diameter of 12mm, and a length of 85mm. The rubber cylindrical plug 18 has a diameter of 12mm and a length of 85mm. The dovetail groove 22 has a groove depth of n, where n is 6mm. The dovetail groove 22 has a front-to-back symmetrical structure and a maximum longitudinal width of m, where m is 45mm. The inclination angle of both groove walls of the dovetail groove 22 is 60°.

[0081] The flexible pressure sensor 5 is a capacitive flexible pressure sensor; the bottom of the groove of the connecting seat 2 and the bottom of the groove of the mounting groove 4 are both arc-shaped.

[0082] The flexible pressure sensor 5 is fabricated using the following steps:

[0083] Step S1: Use a piece of silver-plated fiber knitted fabric with a thickness of 0.2mm, a length of 80mm, and a width of 10mm as the first electrode plate of the sensor. Pour 5 grams of the stirred Ecoflex liquid onto the first electrode plate and use an automatic coating machine to adjust the thickness of the Ecoflex liquid to 0.2mm.

[0084] Step S2: Place the first electrode plate coated with Ecoflex liquid into a drying oven and dry it at 80 degrees Celsius for two minutes, then remove it; then use another piece of silver-plated fiber knitted fabric with the same shape as the first electrode plate as the second electrode plate of the sensor, and cover the second electrode plate on the uncured Ecoflex liquid, thereby obtaining a semi-finished product of capacitive flexible pressure sensor, and place the semi-finished product of capacitive flexible pressure sensor into a drying oven at 80 degrees Celsius until it is completely dried; then cut the cured Ecoflex so that the cured Ecoflex is the same size as the first electrode plate and the second electrode plate.

[0085] Step S3: Take out the cut capacitive flexible pressure sensor semi-finished product and connect a wire to each of the first and second plates using conductive silver paste;

[0086] Step S4: Encapsulation of the sensor: Pour 5 grams of stirred PDMS liquid onto a rigid substrate. Use an automatic coating machine to coat the PDMS liquid to a thickness of 0.05 mm. Place the rigid substrate with the PDMS liquid attached into an 80°C drying oven until completely dry. After drying, remove the substrate and peel the cured PDMS off the rigid substrate. Use a tool to cut the cured PDMS into PDMS cured blocks with a length of 90 mm, a width of 20 mm, and a thickness of 0.05 mm. Repeat this process to obtain two PDMS cured blocks with a length of 90 mm, a width of 20 mm, and a thickness of 0.05 mm. Then, use silicone rubber to adhere the two PDMS cured blocks to the opposite surfaces of the first and second electrodes, respectively. This completes the encapsulation of the sensor, resulting in a finished capacitive flexible pressure sensor.

[0087] Example 2

[0088] The width of the curved protrusion 8 along the longitudinal direction is 22mm;

[0089] The length of the mounting pin 7 is j, and j is 48mm; the taper of the tapered column 19 is 1:50, the longitudinal length is g, and g is 36mm; the diameter of the large end of the tapered column 19 is f, and f is 22mm; the inner diameter of the internal hexagon countersunk hole 21 is 12mm, and the countersunk depth is 10mm; the length of the threaded column 20 is h, and h is 10mm; the external thread type of the threaded column 20 is M10; the connector 6 is a square connector with a longitudinal width of k, and k is 60mm; the connector 6 has a through-hole that is symmetrical from front to back in the middle. Mounting hole 23 has an M10 internal threaded hole of length i in the middle and conical holes with a taper of 1:50 at both ends, where i is 30mm; the hollow cylindrical pin 17 is made of 304 stainless steel, with an outer diameter of 20mm, an inner diameter of 12mm, and a length of 85mm; the rubber cylindrical plug 18 has a diameter of 12mm and a length of 85mm; the dovetail groove 22 has a groove depth of n, where n is 8mm; the dovetail groove 22 has a front-to-back symmetrical structure, and its maximum width along the longitudinal direction is m, where m is 55mm; the inclination angle of both groove walls of the dovetail groove 22 is 60°.

[0090] Example 3

[0091] The width of the curved protrusion 8 along the longitudinal direction is 21mm;

[0092] The length of the mounting pin 7 is j, and j is 45mm; the taper of the tapered column 19 is 1:50, the longitudinal length is g, and g is 35mm; the diameter of the large end of the tapered column 19 is f, and f is 19mm; the inner diameter of the internal hexagon countersunk hole 21 is 12mm, and the countersunk depth is 10mm; the length of the threaded column 20 is h, and h is 8.5mm; the external thread type of the threaded column 20 is M10; the connector 6 is a square connector with a longitudinal width of k, and k is 60mm; the connector 6 has a through-hole that is symmetrical from front to back in the middle. Mounting hole 23 has an M10 internal threaded hole of length i in the middle and conical holes with a taper of 1:50 at both ends, where i is 27mm. The hollow cylindrical pin 17 is made of 304 stainless steel and has an outer diameter of 20mm, an inner diameter of 12mm, and a length of 85mm. The rubber cylindrical plug 18 has a diameter of 12mm and a length of 85mm. The dovetail groove 22 has a groove depth of n, where n is 7.4mm. The dovetail groove 22 has a symmetrical structure and a maximum longitudinal width of m, where m is 52mm. The inclination angle of both groove walls of the dovetail groove 22 is 60°.

[0093] In the description of this invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0094] 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 force-measuring excavator bucket tooth assembly, comprising bucket teeth (1) and a connecting seat (2); characterized in that: The connecting seat (2) is a U-shaped groove with the opening facing right. The end of the bucket (3) is embedded in the inner cavity of the connecting seat (2), and the connecting seat (2) and the bucket (3) are detachably connected by a pin mechanism passing through them. The bottom of the groove of the connecting seat (2) is provided with a through mounting groove (4), and a flexible pressure sensor (5) that contacts the bucket (3) is fixed in the inner cavity of the mounting groove (4). The left end of the connecting seat (2) is provided with a connecting head (6) embedded in the right side of the bucket tooth (1). The connecting head (6) and the bucket tooth (1) are detachably connected by two mounting pins (7) that are distributed in front and behind and arranged opposite to each other. The opposite ends of the two mounting pins (7) are threadedly connected to the connecting head (6). The bucket tooth (1) includes a curved protrusion (8) located in the middle and arranged in the transverse direction. The front and rear sides of the curved protrusion (8) are integrally provided with a sliding part (9) with a concave curved upper surface. The left end of the sliding part (9) is integrally provided with a cutting part (10) with a left lower and right higher upper surface and a planar upper surface. The two sliding parts (9) and the two cutting parts (10) are symmetrically arranged front and back. The width of the curved protrusion (8) along the longitudinal direction is 18mm-22mm; the curve equation corresponding to the intersection line between the upper surface of the curved protrusion (8) and the transverse vertical surface is shown in formula (a): y=-0.0013x 2 -0.0098x+77.53 (a) The x-value of the intersecting line is 0mm-240.5mm, and the corresponding y-value is 77.53mm-0mm. The number of the pin mechanisms is two distributed on the left and right. Each pin mechanism includes a hollow cylindrical pin (17) that passes through the connecting seat (2) and the bucket body (3) in the vertical direction and a rubber cylindrical plug (18) that passes through the middle of the hollow cylindrical pin (17). The upper plate of the connecting seat (2) has a dovetail groove (22) located in the middle and arranged laterally on the lower surface and the upper surface of the lower plate. The bucket body (3) is integrally provided with a dovetail-shaped locking block (24) that matches the position of the dovetail groove (22). The bottom of the dovetail groove (22) has an installation groove I (12) located near the side of the bucket body (3) and connected to the end of the connecting seat (2). The lower surface of the dovetail-shaped locking block (24) located on the lower side of the bucket body (3) has a wire receiving groove (11) that runs through the left and right sides.

2. The excavator bucket tooth assembly with measurable force according to claim 1, characterized in that: The left and right surfaces of the bucket teeth (1) are both longitudinal vertical surfaces; the left part of the front surface of the bucket teeth (1) is a left-rear-right-front oblique vertical surface, and the right part of the front surface is a transverse vertical surface; the left part of the rear surface of the bucket teeth (1) is a left-front-right-rear oblique vertical surface, and the right part of the rear surface is a transverse vertical surface; a reinforcing part (13) is integrally provided on the upper right side of each of the two sliding parts (9), and the reinforcing part (13) on the front side protrudes forward and upward, and the reinforcing part (13) on the rear side protrudes backward and upward; the bucket teeth (1) also include a longitudinal vertical D-shaped connecting block (14) located at the right end, and a triangular block (15) located on the inner side and with a planar upper surface and a C-shaped irregular block (16) located on the outer side and with a C-shaped upper surface are connected between the two reinforcing parts (13) and the connecting block (14).

3. The excavator bucket tooth assembly with measurable force according to claim 2, characterized in that: Both mounting pins (7) include a tapered post (19) on the outer side and a threaded post (20) on the inner side that is threaded into the internal threaded hole of the connector (6). The diameter of the threaded post (20) is smaller than the diameter of the tapered post (19). The outer end face of the tapered post (19) is provided with an internal hexagon countersunk hole (21).

4. The excavator bucket tooth assembly with measurable force according to claim 3, characterized in that: The length of the mounting pin (7) is j, and the value of j ranges from 44mm to 48mm; the taper of the tapered column (19) is 1:50, the length along the longitudinal direction is g, and the value of g ranges from 34mm to 36mm; the diameter of the large end of the tapered column (19) is f, and the value of f ranges from 18mm to 22mm; the inner diameter of the internal hexagon countersunk hole (21) is 12mm, and the countersunk depth is 10mm; the length of the threaded column (20) is h, and the value of h ranges from 8mm to 10mm; the external thread type of the threaded column (20) is M10; the connector (6) is a square connector with a width of k along the longitudinal direction, and k is 60mm; a through-hole is opened in the middle of the connector (6). The mounting holes (23) are symmetrical front and back. The middle part of the mounting holes (23) is an M10 internal thread hole with a length of i, and the two ends are conical holes with a taper of 1:

50. The value of i is 26mm-30mm. The hollow cylindrical pin (17) is made of 304 stainless steel. Its outer diameter is 20mm, its inner diameter is 12mm, and its length is 85mm. The diameter of the rubber cylindrical plug (18) is 12mm and its length is 85mm. The groove depth of the dovetail groove (22) is n, and the value of n is 6mm-8mm. The dovetail groove (22) has a symmetrical front and back structure. Its maximum width along the longitudinal direction is m, and the value of m is 45mm-55mm. The inclination angle of the two groove walls of the dovetail groove (22) is 60°.

5. The excavator bucket tooth assembly with measurable force according to claim 4, characterized in that: The flexible pressure sensor (5) is a capacitive flexible pressure sensor; the bottom of the groove of the connecting seat (2) and the bottom of the groove of the mounting groove (4) are both arc-shaped.

6. The excavator bucket tooth assembly with measurable force according to claim 5, characterized in that: The flexible pressure sensor (5) is fabricated using the following steps: Step S1: Use a piece of silver-plated fiber knitted fabric with a thickness of 0.2mm, a length of 80mm, and a width of 10mm as the first electrode plate of the sensor. Pour 5 grams of the stirred Ecoflex liquid onto the first electrode plate and use an automatic coating machine to adjust the thickness of the Ecoflex liquid to 0.2mm. Step S2: Place the first electrode plate coated with Ecoflex liquid into a drying oven and dry it at 80 degrees Celsius for two minutes, then remove it; then use another piece of silver-plated fiber knitted fabric with the same shape as the first electrode plate as the second electrode plate of the sensor, and cover the second electrode plate on the uncured Ecoflex liquid, thereby obtaining a semi-finished product of capacitive flexible pressure sensor, and place the semi-finished product of capacitive flexible pressure sensor into a drying oven at 80 degrees Celsius until it is completely dried; then cut the cured Ecoflex so that the cured Ecoflex is the same size as the first electrode plate and the second electrode plate. Step S3: Take out the cut capacitive flexible pressure sensor semi-finished product and connect a wire to each of the first and second plates using conductive silver paste; Step S4: Encapsulate the sensor: Pour 5 grams of stirred PDMS liquid onto a rigid substrate, use an automatic coating machine to coat the PDMS liquid to a thickness of 0.05 mm, and place the rigid substrate with the PDMS liquid attached into an 80°C drying oven until completely dry. After drying, the cured PDMS is removed from the rigid substrate and cut into PDMS blocks with a length of 90mm, a width of 20mm, and a thickness of 0.05mm using tools. This process is repeated to obtain two PDMS blocks with a length of 90mm, a width of 20mm, and a thickness of 0.05mm. Then, silicone rubber is used to adhere the two PDMS blocks to the opposite surfaces of the first and second electrodes, respectively, thus completing the sensor encapsulation and obtaining the finished capacitive flexible pressure sensor.

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