Device and method for detecting coaxiality of main oil cylinder and concrete cylinder of plunger type concrete pump

Abstract

The invention relates to the technical field of coaxiality detection, in particular to a plunger type concrete pump main oil cylinder and concrete cylinder coaxiality detection device and method.The plunger type concrete pump main oil cylinder and concrete cylinder coaxiality detection device comprises a main oil cylinder, a concrete cylinder and a water tank arranged between the main oil cylinder and the concrete cylinder, a connecting rod is arranged in the water tank, and the connecting rod is connected with a cylinder rod in the main oil cylinder and a concrete piston in the concrete cylinder; a length measuring device and a strain force measuring device are arranged on the connecting rod, the length measuring device is used for measuring the length information of the connecting rod extending into the concrete cylinder, and the strain force measuring device is used for measuring the strain force information of the section, which is L away from the stress point of the concrete piston, on the connecting rod; and the coaxiality deviation condition of the concrete piston at the specific position of the concrete cylinder is calculated according to the length information and the strain force information. According to the invention, the coaxiality of the concrete pump finished product can be conveniently detected without disassembling and assembling the assembled parts of the concrete pump.

Description

Technical Field

[0001] The invention relates to the technical field of coaxiality detection, and in particular to a device and method for detecting the coaxiality between a main oil cylinder and a concrete cylinder of a plunger type concrete pump. Background Art

[0002] A plunger concrete pump is a device that uses pressure to continuously transport concrete along a pipeline. It is mainly composed of a hopper, a hydraulic cylinder and a piston, a concrete cylinder, a hydraulic system, and a power system. The hydraulic system pushes the piston to reciprocate through pressure. The piston sucks the material when it moves backward, and presses the concrete in the concrete cylinder into the delivery pipe when it moves forward. The coaxiality detection of the main oil cylinder and the concrete cylinder is one of the most important factors affecting the pumping performance of the plunger concrete pump; if the coaxiality is not good, it will cause eccentric wear of the piston, increase the pumping resistance, and reduce the life of the piston.

[0003] At present, there are many methods for detecting the coaxiality of the main oil cylinder and the concrete cylinder, but most of them need to arrange multiple radial distance measuring devices at the insertion end of the piston rod, and combine with position detection equipment to detect the coaxiality error between the center axis of the piston rod and the center axis of the conveying cylinder at different axial positions. During the detection process, the piston needs to be removed and the radial distance measuring device needs to be installed. After the measurement is completed, the distance measuring device needs to be removed and the piston needs to be installed. The measurement process is cumbersome, and the influence of the assembly deviation of the distance measuring device or the piston on the measurement result is not considered. It belongs to the assembly process detection, does not involve the assembly of the concrete cylinder, and cannot reflect the actual coaxiality error of the piston and the concrete cylinder during the movement of the main oil cylinder.

[0004] Therefore, there is an urgent need for a device and method for detecting the coaxiality of a main oil cylinder of a concrete pump and a concrete cylinder, which is convenient to measure and does not require removal of the piston. Summary of the invention

[0005] The present invention aims to solve the problem that in the prior art, the coaxiality of a finished concrete delivery pump cannot be detected by terminal results, and the piston and radial distance measuring equipment need to be disassembled and assembled, which makes the measurement inconvenient. A method and device for detecting the coaxiality of a main oil cylinder of a plunger type concrete pump and a concrete cylinder are provided. The coaxiality of the finished concrete pump can be conveniently detected without disassembling the assembled parts of the concrete pump.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A device for detecting the coaxiality of a main oil cylinder and a concrete cylinder of a plunger-type concrete pump comprises a main oil cylinder and a concrete cylinder, and a water tank arranged between the main oil cylinder and the concrete cylinder. A connecting rod is arranged in the water tank, and the connecting rod connects the cylinder rod in the main oil cylinder and the concrete piston in the concrete cylinder. A length measuring device and a strain force measuring device are arranged on the connecting rod. The length measuring device is used to measure the length information of the connecting rod extending into the concrete cylinder, and the strain force measuring device is used to measure the strain force information at a cross section of the connecting rod at a distance L from the force point of the concrete piston. The strain force measuring device and the length measuring device are both placed outside the concrete cylinder, and do not affect the internal structure of the concrete cylinder during the test, and there is no need to frequently disassemble and assemble the piston and radial distance measuring equipment. The coaxiality offset of the concrete piston at a specific position of the concrete cylinder is calculated based on the length information and the strain force information. The detection saves time and effort, and the assembly deviation caused by the assembly of the piston and the distance measuring equipment will not affect the measurement results.

[0008] Furthermore, the main oil cylinder is connected to a hydraulic control system, and the hydraulic control system drives the concrete piston to move in the concrete cylinder. The hydraulic control system controls the movement of the concrete piston in the concrete cylinder through a connecting rod.

[0009] Furthermore, the length measuring device includes a wire sensor, the main body of which is fixed to the upper surface of the water tank through a mounting bracket, a pulley is provided in the water tank, and the wire end of the wire sensor is passed around the pulley and fixed to the connecting rod. The wire sensor is used to detect the length of the connecting rod extending into the concrete cylinder.

[0010] Furthermore, the strain force measurement device includes a set of strain gauges attached to the surface of the connecting rod and a strain gauge electrically connected to the strain gauge, and the strain gauge converts the electrical signal generated by the strain gauge due to deformation into strain force information. When the connecting rod is subjected to external force, the surface is mechanically deformed, and the resistance value of the strain gauge changes accordingly, thereby measuring the surface strain of the object.

[0011] Furthermore, four strain gauges are evenly arranged on the connecting rod along the circumference, and the four strain gauges are respectively located at the top position, the bottom position and the front and rear of the horizontal position, and the surface of each strain gauge is covered with a waterproof patch. The waterproof patch is used to protect the strain gauge.

[0012] A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger type concrete pump, using the above-mentioned coaxiality detection device for the main oil cylinder and the concrete cylinder of a plunger type concrete pump, comprises the following steps:

[0013] Step 1: Before the concrete piston enters the concrete cylinder (i.e., when it is in a free and unconstrained state), calibrate the strain force measuring device; after the concrete piston has just completely entered the concrete cylinder, calibrate the length measuring device; and use it as a reference for data changes in subsequent concrete piston movements.

[0014] Step 2: Start the hydraulic control system. The cylinder rod drives the concrete piston to move slowly in the concrete cylinder. The concrete piston moves to a preset position. Obtain the length of the connecting rod extending into the concrete cylinder and the stress value at the section of the connecting rod at a distance L from the force point of the concrete piston.

[0015] Step three, calculate the lateral force on the concrete piston stress point based on the stress value.

[0016] Step 4: Calculate the coaxiality deviation value of the concrete piston at the preset position according to the relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston.

[0017] Step 5: Data correlation is performed between the length value and the coaxiality deviation value, and the overall coaxiality deviation direction and deviation value of the concrete piston in the entire concrete cylinder are calculated. The lateral deformation of the concrete piston is the coaxiality deviation value of the concrete piston.

[0018] Furthermore, in step 2, for a single preset position, stress values ​​of at least three points on the cross section are measured. By comparing the stress values, the direction of the coaxiality deviation can be determined.

[0019] Furthermore, in step three, the lateral force on the force-bearing point of the concrete piston is calculated according to the stress value, and the lateral force is calculated specifically by the following formula:

[0020]

[0021] Among them, F represents the lateral force, M represents the bending moment of the section, W represents the bending section modulus coefficient, and σ1 represents the stress value. By measuring the stress value, the lateral force on the piston can be calculated.

[0022] Furthermore, in step 4, the process of applying lateral force to the concrete piston is simulated, and the applied lateral force and the lateral deformation at this time are sampled during the simulation process, and the relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston is obtained by fitting according to the sampled data. This is used to compare with the lateral force calculated according to the stress value, inversely infer the lateral deformation of the concrete piston, and then obtain the coaxiality deviation value.

[0023] Furthermore, at least three preset positions are set in step 2. By comparing the stress values ​​at the three positions, the displacement of the concrete piston in the concrete cylinder is determined.

[0024] Through the above technical solution, the beneficial effects of the present invention are:

[0025] 1. After the coaxiality detection of the main oil cylinder and the concrete cylinder, the present invention does not need to remove the piston and the detection device, thereby avoiding the measurement result deviation caused by assembly error after the coaxiality detection. Compared with the existing coaxiality detection that requires the removal of the piston and the distance measuring device, the measurement result is more in line with the actual situation during actual use.

[0026] 2. The present invention can be used for testing during the manufacturing process of the concrete pump, and can also be used for testing during the use of the concrete pump, without the need to disassemble and remodel the finished concrete pump, which greatly saves manpower and material resources and improves production efficiency.

[0027] 3. The measuring process of the present invention is simple and can be tested after assembly. The eccentric wear of the finished concrete pump after the concrete piston is assembled can be directly measured, and the coaxiality can be monitored and adjusted in real time to ensure the normal operation of the concrete pumping system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the water tank of the present invention;

[0030] Figure 3 It is a structural schematic diagram of the concrete piston movement in Example 2 of the present invention;

[0031] Figure 4 It is a structural schematic diagram of the concrete piston offset in Example 4 of the present invention;

[0032] Figure 5 is a schematic structural diagram of the concrete piston offset in Example 5 of the present invention;

[0033] Figure 6 It is a structural schematic diagram of the concrete piston offset in Example 6 of the present invention;

[0034] The numbers in the accompanying drawings are: 1 is the main oil cylinder, 11 is the cylinder barrel, 12 is the cylinder rod, 2 is the water tank, 3 is the connecting rod, 4 is the strain force measuring device, 41 is the strain gauge, 42 is the strain measuring instrument, 5 is the concrete piston, 6 is the concrete cylinder, 7 is the hydraulic control system, 8 is the computer, 9 is the length measuring device, 91 is the wire sensor, 92 is the mounting bracket, 911 is the hanging ring, and 921 is the pulley. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0036] Example 1

[0037] like Figure 1-2As shown, this embodiment provides a device and method for detecting the coaxiality between the main oil cylinder of a plunger concrete pump and a concrete cylinder. The device for detecting the coaxiality between the main oil cylinder of a plunger concrete pump and a concrete cylinder comprises a concrete delivery pump, a hydraulic control system 7, a length measuring device 9 and a strain force measuring device 4. As an implementable method, the length measuring device 9 and the strain force measuring device 4 are electrically connected to a computer 8, and the length information output by the length measuring device 9 and the strain force information output by the strain force measuring device 4 are transmitted to the computer 8, and the computer 8 is used to calculate the coaxiality deviation of the concrete piston 5 at a specific position of the concrete cylinder 6.

[0038] The hydraulic control system 7 is connected to the main oil cylinder 1 through a hydraulic pipeline to provide flow and pressure for the movement of the main oil cylinder. The hydraulic control system 7 drives the concrete piston 5 to move in the concrete cylinder 6. The length measuring device 9 is connected to the computer 8 through a line to provide the measured length information. The strain force measuring device 4 is connected to the computer 8 through a line to provide the measured and processed strain stress information.

[0039] like Figure 1 As shown, the concrete delivery pump includes a main oil cylinder 1 and a concrete cylinder 6, and a water tank 2 arranged between the main oil cylinder 1 and the concrete cylinder 6. A connecting rod 3 is arranged in the water tank 2, and the connecting rod 3 connects the cylinder rod 12 in the main oil cylinder 1 and the concrete piston 5 in the concrete cylinder 6. A hopper is arranged at the right end of the concrete cylinder 6. The main oil cylinder 1 includes a cylinder barrel 11 and a cylinder rod 12, and the cylinder barrel 11 is coaxial with the cylinder rod 12. The right end of the cylinder barrel 11 is fixed to the left hole of the water tank 2 by bolts, and the concrete cylinder 6 is fixed to the right hole of the water tank 2. The holes on both sides of the water tank are processed to ensure their coaxiality, that is, the cylinder rod 12 and the concrete cylinder 6 are theoretically coaxially arranged. The concrete piston 5 is an elastic body that is approximately cylindrical and is located in the concrete cylinder 6. The cylinder rod 12 of the main oil cylinder 1 is screwed to the concrete piston 5 through the connecting rod 3.

[0040] The connecting rod 3 is provided with a length measuring device 9 and a strain force measuring device 4. The length measuring device 9 is used to measure the length information of the connecting rod 3 extending into the concrete cylinder 6. The strain force measuring device 4 is used to measure the strain force information at the cross section of the connecting rod 3 at a distance L from the force point of the concrete piston 5.

[0041] The length measuring device 9 includes a wire sensor 91, the main body of which is fixed to the upper surface of the water tank 2 via a mounting bracket 92, the mounting bracket 92 is fixed to the upper plane of the water tank 2 via bolts, a pulley 921 is provided in the water tank 2, and the wire end of the wire sensor 91 is passed around the pulley 921 and fixed to the connecting rod 3 so as to extend along with the movement of the concrete piston 5; specifically, a hanging ring 911 is arranged at the wire end of the wire sensor 91, which can be fixed to the connecting bolt of the connecting rod 3. As an implementable embodiment, the wire sensor 91 can use a rugged series C60 wire encoder produced by German Kubler Co., Ltd.

[0042] The strain force measuring device 4 includes a set of strain gauges 41 attached to the surface of the connecting rod 3 and a strain measuring instrument 42 electrically connected to the strain gauges 41. The strain measuring instrument 42 is electrically connected to the computer 8 and converts the electrical signal generated by the strain gauges 41 due to deformation into strain force information and transmits it to the computer 8. The strain gauges 41 are evenly pasted along the circumference of a certain section on the connecting rod 3, and the main tensile test direction is the same as the axis direction of the main oil cylinder 1, so as to test the compression and elongation of the connecting rod 3.

[0043] The computer 8 is electrically connected to the length measuring device 9 and the stress measuring device 4 to obtain the data of the wire sensor 91 and the measurement data of the strain gauge 41, and obtains the coaxiality information (including the offset and the offset direction) when the concrete piston 5 moves to different positions of the concrete cylinder 6 through calculation and analysis.

[0044] The present embodiment does not specifically limit the shape of the connecting rod 3 and the number of strain gauges 41. The shape of the connecting rod 3 may be cylindrical, square prism or other shapes, and the number of strain gauges 41 may be multiple. The strain gauge 42 may use the DH3816N stress strain gauge produced by Jiangsu Donghua Testing Technology Co., Ltd. Each instrument has both wireless and wired communication modes, and can be controlled using computer software or mobile phone APP.

[0045] As an implementation method, the cross section of the connecting rod 3 is circular, and four strain gauges 41 are evenly arranged on the connecting rod 3 along the circumference. The four strain gauges 41 are respectively located at the top position, the bottom position, and the front and rear of the horizontal position. The test direction of this group of strain gauges 41 is the same as the axial direction of the cylinder rod 12, and they are longitudinally glued to the connecting rod 3 by special glue. The surface of each strain gauge 41 is covered with a waterproof patch, which is made of silicone rubber. The waterproof patch protects the strain gauge 41 and prevents the strain gauge 41 from being eroded by water. It should be noted that Examples 2 to 6 are all such cases.

[0046] A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger type concrete pump, using the above-mentioned coaxiality detection device for the main oil cylinder and the concrete cylinder of a plunger type concrete pump, comprises the following steps:

[0047] Step 1: Before the concrete piston 5 enters the concrete cylinder 12 (i.e., when it is in a free and unconstrained state), the strain force measuring device 4 is calibrated, and its state is used as a reference for subsequent strain stress data changes; after the concrete piston 5 has just completely entered the concrete cylinder 12, the length measuring device 9 is calibrated and its position is used as the initial position, and the measured data is used as a value of 0, which is used as a reference for data changes in subsequent concrete piston movements.

[0048] Step 2: Start the hydraulic control system 7, the cylinder rod 12 drives the concrete piston 5 to move slowly in the concrete cylinder 6, the concrete piston 5 moves to the preset position, and obtains the length value of the connecting rod 3 extending into the concrete cylinder 6 and the stress value at the cross section of the connecting rod 3 at a distance L from the force point of the concrete piston 5; in this embodiment, the length value is measured by the wire sensor 91, and the stress value is measured by the strain gauge 41 and the strain gauge 42. In order to improve the test accuracy, for a single preset position, the stress values ​​of at least three points on the cross section are measured.

[0049] Step three, calculate the lateral force on the force point of the concrete piston 5 according to the stress value; in this embodiment, the lateral force is calculated by the following formula:

[0050]

[0051] Among them, F represents the lateral force, M represents the bending moment of the section, W represents the bending section modulus coefficient, and σ1 represents the stress value.

[0052] Step 4: Calculate the coaxiality deviation value of the concrete piston 5 at the preset position according to the relationship between the lateral force on the concrete piston 5 and the lateral deformation of the concrete piston 5. The specific method is as follows:

[0053] The process of applying lateral force to the concrete piston 5 is simulated. During the simulation, the applied lateral force and the lateral deformation at this time are sampled. The relationship between the lateral force on the concrete piston 5 and the lateral deformation of the concrete piston 5 is fitted based on the sampled data. The results can be presented in the form of charts.

[0054] Step 5, the length value is data-associated with the coaxiality deviation value, and the overall coaxiality deviation direction and deviation value of the concrete piston 5 in the entire concrete cylinder 6 are calculated. In order to improve the accuracy of the test results, at least three preset positions are set in step 2. By comparing the coaxiality deviation values ​​of multiple positions, the overall coaxiality deviation is obtained. The detailed calculation process is detailed in Examples 4 to 6.

[0055] As an implementable method, in step 4, the relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston is measured, and the process may be:

[0056] 1. Put the concrete piston 5 on the fixed shaft, and put the outer side of the concrete piston 5 into the cylinder sleeve (the inner diameter of the cylinder sleeve is processed according to the tolerance required by the concrete cylinder diameter, and force can be applied and deformation can be measured on one side of the cylinder sleeve).

[0057] 2. Apply force: Gradually increase the force applied to the cylinder sleeve and record the force value each time it is increased.

[0058] 3. Measure deformation: Measure the deformation of the concrete piston at different force values ​​at the same time, specifically the movement of the cylinder sleeve relative to its original position.

[0059] 4. Data recording: record the deformation corresponding to each level of force to form a one-to-one table; or use the force value as the horizontal axis and the deformation as the vertical axis to draw a "force-deformation curve".

[0060] Alternatively, the above process may also be performed by taking the cylinder sleeve as a fixed object and applying force to the shaft on which the concrete piston 5 is mounted to achieve the same effect.

[0061] In the coaxiality detection method of the present invention, as described above, by evenly distributing a group of strain gauges 41 on a certain cross section of the connecting rod 3, the distribution of the force on the cross section can be measured. Combined with the material properties of the connecting component, the cross section form and size, and the axial distance from the cross section to the force point of the concrete piston 5, the magnitude and direction of the lateral force on the concrete piston 5 can be calculated; further, from the relationship between the deformation of the concrete piston 5 and the lateral force (which can be measured in advance through experiments), the offset and offset direction of the installation center point of the concrete piston 5 (on the axis of the cylinder rod 12 of the main oil cylinder 1) and the axis of the concrete cylinder 6 can be calculated, that is, the coaxiality error. Moreover, by setting a wire sensor 91 to detect the depth of the concrete piston 5 in the concrete cylinder 6 and the coaxiality error when the concrete piston 5 reaches a specific position, the coaxiality detection data over the entire stroke length can be obtained.

[0062] Therefore, according to the present invention, the distribution of the force acting on the detection section can be accurately and conveniently detected. As a result, it is possible to determine whether the concrete piston 5 has eccentric wear and the position of the eccentric wear along the rotation direction of the axis of the cylinder rod 12 of the main oil cylinder 1 according to the obtained force distribution, combined with the size of the measurement section and the overhang length to the concrete piston 5, and at the same time, the offset of the center of the concrete piston 5 from the center of the axis of the concrete cylinder 6 can be calculated in combination with the relationship between the material deformation of the concrete piston 5 and the eccentric pressure, so that the finished product detection of the coaxiality of the main oil cylinder 1 and the concrete cylinder 6 of the concrete delivery pump can be realized without disassembling the parts.

[0063] Example 2: Single-point coaxiality detection example 1

[0064] When the concrete piston moves to the preset position, Figure 3 As shown, assuming that there is a coaxial deviation η1 between the theoretical center of the concrete piston and the center of the concrete cylinder at this position, it means that the edge of the concrete piston is further compressed by η1 compared to when there is no coaxial deviation. By looking up the table (which can be obtained in advance from the test), it is known that the concrete piston is subjected to a lateral force F1 at this time. After calculation, the bending moment of the measured section can be obtained:

[0065] M1=F1·L

[0066] Assuming that the measured section of the connecting rod is a circular section with a diameter of d, its bending section modulus coefficient is:

[0067]

[0068] The stress value at the upper strain gauge measurement point is:

[0069]

[0070] From the above relationship, it can be known that if the stress value at the upper strain gauge is measured by the strain force measurement device as σ1, then the lateral force on the concrete piston can be inferred as:

[0071]

[0072] From the known relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston, the lateral deformation of the concrete piston η1 can be found out, that is, the coaxiality deviation is determined to be η1.

[0073] Example 3: Single-point coaxiality detection example 2

[0074] This embodiment is basically the same as the embodiment 2, except that the measured cross section of the connecting rod is a rectangular cross section with a width of b and a height of h. Then, the bending section modulus coefficient is:

[0075]

[0076] The stress value at the upper strain gauge measurement point is:

[0077]

[0078] From the above relationship, it can be known that if the stress value at the upper strain gauge is measured by the strain force measurement device as σ1, then the lateral force on the concrete piston can be inferred as:

[0079]

[0080] From the known relationship between the lateral force on the concrete piston and the deformation of the concrete piston, the deformation of the concrete piston η1 can be found out, that is, the coaxiality deviation is determined to be η1.

[0081] Example 4: Overall coaxiality information calculation example 1

[0082] In this embodiment, the concrete piston has no coaxial position deviation in the horizontal direction, but has coaxial position deviation in the up and down directions.

[0083] like Figure 4 As shown in the figure, assuming that the coaxiality of the concrete piston is measured at the marked positions l1, l2, and l3, the three sets of stress values ​​at the upper and lower positions are [σ 上1 , σ 下1 ]、[σ 上2 , σ 下2 ]、[σ 上3 , σ 下3 ], if σ 上1 =σ 上2 =σ 上3 And they are all positive, σ 下1 =σ 下2 =σ 下3 And they are all negative values, indicating that the upper part of the concrete piston is subjected to a downward lateral force, resulting in tension above the test part and compression below, which can determine the direction of the force and the direction of coaxiality deviation. And the specific relationship between the lateral force on the concrete piston and the stress value at the test point is

[0084] F=f(σ)

[0085] The size of the coaxiality offset value can be obtained.

[0086] In the above situation, the stress value remains unchanged at different positions, indicating that the lateral force has not changed, that is, the coaxiality value at different marked positions has not changed, that is, the motion axis of the center of the concrete piston is parallel to the axis of the concrete cylinder but eccentric.

[0087] Example 5: Overall coaxiality information calculation example 2

[0088] In this embodiment, the concrete piston has no coaxial position deviation in the horizontal direction, but has coaxial position deviation in the up and down directions.

[0089] like Figure 5 As shown in the figure, assuming that the coaxiality of the concrete piston is measured at the marked positions l1, l2, and l3, the three sets of stress values ​​at the upper and lower positions are [σ 上1 , σ 下1 ]、[σ 上2 , σ 下2 ]、[σ 上3 , σ 下3 ], if σ 上1 <σ上2 <σ 上3 And they are all positive, σ 下1 >σ 下2 >σ 下3 And they are all negative values, indicating that the upper part of the piston has been subjected to downward lateral force, resulting in tension above the test part and compression below, which can determine the direction of force and coaxial deviation. However, their values ​​are different, according to the specific relationship between the lateral force on the concrete piston and the stress value at the test point

[0090] F=f(σ)

[0091] It can be concluded that the coaxiality offset value is gradually increasing.

[0092] In the above situation, the stress value changes gradually at different positions, indicating that the lateral force is also changing, that is, the coaxiality value at different marked positions is also changing, that is, the moving axis of the concrete piston center and the concrete cylinder axis form a certain angle.

[0093] Example 6: Overall coaxiality information calculation example 3

[0094] In this embodiment, the concrete piston has no coaxial position deviation in the horizontal direction, but has coaxial position deviation in the up and down directions.

[0095] like Figure 6 As shown in the figure, assuming that the coaxiality of the concrete piston is measured at the marked positions l1, l2, and l3, the three sets of stress values ​​at the upper and lower positions are [σ 上1 , σ 下1 ]、[σ 上2 , σ 下2 ]、[σ 上3 , σ 下3 ], if σ 上1 is a negative value, σ 上2 =0,σ 上3 is a positive value; and σ 下1 is a positive value, σ 下2 =0,σ 下3 It is a negative value. This means that the lower part of the piston is first subjected to an upward lateral force, resulting in compression above the test part and tension below; then at position l2, the coaxiality deviation is zero and there is no lateral force; then at position l3, the upper part of the piston is subjected to a downward lateral force, resulting in tension above the test part and compression below. The specific relationship between the lateral force on the concrete piston and the stress value at the test point is:

[0096] F=f(σ)

[0097] It can be concluded that the coaxiality offset value first decreases and then increases.

[0098] In the above situation, the stress value changes gradually at different positions, indicating that the lateral force is also changing, that is, the coaxiality value at different marked positions is also changing, that is, the moving axis of the concrete piston center and the concrete cylinder axis form a certain angle.

[0099] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A device for detecting the coaxiality of a main oil cylinder and a concrete cylinder of a plunger-type concrete pump, comprising a main oil cylinder (1) and a concrete cylinder (6), and a water tank (2) arranged between the main oil cylinder (1) and the concrete cylinder (6), wherein a connecting rod (3) is arranged in the water tank (2), and the connecting rod (3) connects a cylinder rod (12) in the main oil cylinder (1) and a concrete piston (5) in the concrete cylinder (6), characterized in that: The connecting rod (3) is provided with a length measuring device (9) and a strain force measuring device (4), wherein the length measuring device (9) is used to measure the length information of the connecting rod (3) extending into the concrete cylinder (6), and the strain force measuring device (4) is used to measure the strain force information at a cross section of the connecting rod (3) at a distance L from a force point of the concrete piston (5); and the coaxiality deviation of the concrete piston (5) at a specific position of the concrete cylinder (6) is calculated based on the length information and the strain force information.

2. The device for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger-type concrete pump according to claim 1 is characterized in that: The main oil cylinder (1) is connected to a hydraulic control system (7), and the hydraulic control system (7) drives the concrete piston (5) to move in the concrete cylinder (6).

3. The device for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger-type concrete pump according to claim 1, characterized in that: The length measuring device (9) comprises a wire sensor (91), the wire sensor (91) being fixed on the upper surface of the water tank (2), a pulley (921) being arranged in the water tank (2), and the wire end of the wire sensor (91) passing around the pulley (921) is fixed on the connecting rod (3).

4. The device for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger-type concrete pump according to claim 1, characterized in that: The strain force measuring device (4) comprises a group of strain gauges (41) attached to the surface of the connecting rod (3) and a strain measuring instrument (42) electrically connected to the strain gauges (41), wherein the strain measuring instrument (42) converts an electrical signal generated by the strain gauges (41) due to deformation into strain force information.

5. The device for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger-type concrete pump according to claim 4 is characterized in that: Four strain gauges (41) are evenly arranged on the connecting rod (3) along the circumferential direction. The four strain gauges (41) are respectively located at the top position, the bottom position and the front and rear of the horizontal position. The surface of each strain gauge (41) is covered with a waterproof patch.

6. A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger concrete pump, using the coaxiality detection device for the main oil cylinder and the concrete cylinder of a plunger concrete pump according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: before the concrete piston enters the concrete cylinder, the strain force measuring device is calibrated; after the concrete piston has just completely entered the concrete cylinder, the length measuring device is calibrated; Step 2: Start the hydraulic control system, the cylinder rod drives the concrete piston to move in the concrete cylinder, the concrete piston moves to a preset position, and obtains the length of the connecting rod extending into the concrete cylinder and the stress value at the cross section of the connecting rod at a distance L from the force point of the concrete piston; Step 3, calculating the lateral force on the concrete piston stress point according to the stress value; Step 4, calculating the coaxiality deviation value of the concrete piston at the preset position according to the relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston; Step 5: Data association is performed between the length value and the coaxiality deviation value, and the overall coaxiality deviation direction and deviation value of the concrete piston in the entire concrete cylinder are calculated.

7. A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger-type concrete pump according to claim 6, characterized in that: In step 2, for a single preset position, stress values ​​at at least three points on the cross section are measured.

8. The method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger concrete pump according to claim 6, characterized in that: In step three, the lateral force on the force-bearing point of the concrete piston is calculated according to the stress value, and the lateral force is calculated specifically by the following formula: Among them, F represents the lateral force, M represents the bending moment of the section, W represents the bending section modulus coefficient, and σ1 represents the stress value.

9. A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger concrete pump according to claim 6, characterized in that: In step 4, the process of applying lateral force to the concrete piston is simulated, and the applied lateral force and the lateral deformation at this time are sampled during the simulation process. The relationship between the lateral force on the concrete piston and the lateral deformation of the concrete piston is obtained by fitting the sampled data.

10. A method for detecting the coaxiality between the main oil cylinder and the concrete cylinder of a plunger concrete pump according to any one of claims 6 to 9, characterized in that: In step 2, at least three preset positions are set.

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