WO2020232799A1 - Pressure sensor for weighing load of mine multi-rope hoist - Google Patents

Abstract

A pressure sensor for weighing a load of a mine multi-rope hoist, comprising a base (2) and an end cover (3). The cross section of the end cover (3) is T-shaped, a groove (6) is provided on an upper end face of the end cover, and a stepped blind hole (7) is provided in the interior below the groove (6); a wire channel (9) in communication with the stepped blind hole (7) is provided on the circumference of the end cover (3); a cylindrical oil chamber (10) is coaxially provided below the stepped blind hole (7), a lower end of the cylindrical oil chamber (10) penetrates through the bottom of the end cover (3), a strain beam (11) is provided in a gap between an upper end of the cylindrical oil chamber (10) and a lower end face of the stepped blind hole (7), and a strain gage (8) is attached to an upper surface of the strain beam (11); the base (2) is U-shaped, an upper portion of the inner side of the groove on the upper end surface of the base is in threaded fit with an upper portion of the periphery of a boss at a lower end surface of the end cover (3), and a flat oil chamber (12) is formed between a upper end face of the groove and a lower end face of the boss; an oil injection channel (23) in communication with the oil chamber (12) is provided on the circumference of the outer side of the base (2); a support base (13) under the base (2) is mounted in a groove formed on a slide block (14) of a balance cylinder (4); a part below the oil chamber (12) and between the oil chamber and the support base (13) is a cantilever beam (15); and a perforated plate (16) is embedded in the cylindrical oil chamber (10). The sensor can improve the accuracy of calculating the hoist load.

Description

Pressure sensor for load weighing of mine multi-rope hoist Technical field

The invention relates to a pressure sensor, in particular to a pressure sensor used for load weighing of a mine multi-rope hoist, and belongs to the technical field of mine hoists.

Background technique

The hoisting system is the "throat" of coal production and transportation, and its normal operation plays an important role in the life safety of miners and the production safety of coal mines. During the operation of the hoisting system, it is difficult to directly measure the load of the hoist due to the constraints of the on-site environment. Considering that the hoist is suspended at the end of the wire rope, real-time weighing of the total load of the hoist can be achieved indirectly by measuring the tension of the wire rope.

At present, it is common to monitor the wire rope tension by measuring the oil pressure of the balancing cylinder in the wire rope tension automatic balancing device of the multi-rope hoist. However, due to the friction between the piston rod and the inner wall of the cylinder, the measured wire rope tension is not accurate enough. In order to solve this problem, the prior art installs an ordinary pressure sensor between the piston rod and the slider of the balance cylinder. However, due to the uneven surface of the tank and wind resistance, the steel wire rope vibrates more severely, so the measured data will be A lot of sudden jump interference causes a large gap between the measured wire rope tension and the actual load of the hoist.

Summary of the invention

In view of the above-mentioned problems in the prior art, the present invention provides a pressure sensor for load weighing of a mine multi-rope hoist. The sensor can eliminate the data mutation interference caused by the vibration of the wire rope during the measurement process, and improve the load of the hoist. The accuracy of the actual value calculation.

In order to achieve the above objective, the present invention provides a pressure sensor for load weighing of a mine multi-rope hoist, which includes a sensor body, the sensor body includes a base and an end cover mounted on the base, the end cover has an inverted cross section Convex shape, the upper end surface is provided with a groove adapted to the piston rod of the balance cylinder, and the end cover below the groove is provided with a stepped blind hole; the end cover is provided with a wire channel intersecting with the stepped blind hole; a stepped blind hole A cylindrical oil cavity is coaxially opened below the bottom of the cylindrical oil cavity, the lower end of the cylindrical oil cavity penetrates the bottom of the end cover, the gap between the upper end of the cylindrical oil cavity and the lower end surface of the stepped blind hole forms a strain beam, and the strain gauge is attached to the upper surface of the strain beam;

The cross-section of the base is concave, and the upper part of the inner side of the groove on the upper end face is threadedly matched with the upper part of the outer periphery of the boss on the lower end face of the end cover. The space between the upper end of the groove and the lower end of the boss forms a flat oil cavity; The oil injection channel intersecting with the oil cavity; the lower support seat of the base is installed in the groove opened on the slider of the balance oil cylinder; the part between the lower part of the flat oil cavity and the support seat is a cantilever beam;

The cylindrical oil cavity and the flat oil cavity together form a closed oil cavity;

The cylindrical oil cavity is embedded with a perforated plate, and the perforated plate includes a rigid plate body and a plurality of micro holes opened on the rigid plate body, the outer circumference of the rigid plate body and the inner wall of the cylindrical oil cavity near the lower end work close with;

The cylindrical oil cavity and the flat oil cavity are connected by micropores

Further, the thickness of the perforated plate is 1 mm, the diameter of the micro-holes is 1.4 mm, the distance between the micro-holes is 3.5 mm, and the distance between the end surface of the perforated plate and the top of the cylindrical oil cavity is 7 mm.

Further, a copper sealing gasket is provided at the threaded fitting position of the groove of the base and the boss of the end cover.

Further, the bottom diameter of the stepped blind hole is larger than the diameter of the cylindrical oil cavity.

Further, a C-shaped groove is provided on the outer periphery of the support base, and the C-shaped groove is matched with the upper end of the groove of the slider.

Further, the strain gauge is a circular strain gauge with a diameter slightly smaller than the bottom diameter of the stepped blind hole.

In the present invention, the pressure sensor is installed between the piston rod and the sliding block of the oil cylinder of the elevator wire rope tension automatic balance suspension device, and the upper end cover is matched with the balance oil cylinder piston rod to bear the positive pressure on the piston rod, and the positive pressure passes The end cover is transferred to the base, and the support seat matched with the slider at the lower end of the base bears the support reaction force generated by the slider. The cantilever beam of the base is bent and deformed under the combined action of the positive pressure and the support reaction force, so that the volume of the oil cavity filled with oil The change occurs and the oil pressure is generated inside the oil cavity. The pressurized oil flow squeezes into the cylindrical oil cavity space from the flat oil cavity through the micro holes of the perforated plate, and the strain beam at the upper end of the cylindrical oil cavity occurs under the action of oil pressure. Deformation, the strain gauge close to the upper end surface of the strain beam outputs the electrical signal of the strain beam deformation, thereby measuring the tension of each steel wire rope, and the total load raised by the hoist can be obtained by the upper computer processing and conversion. Since the pressure sensor is provided with a perforated plate between the flat oil cavity and the cylindrical oil cavity, the potential energy contained in the pressure oil flowing through the perforated plate is fully dissipated by the reciprocating friction with the micro-holes, and finally passes through the squeeze sensor The strain beam makes the strain gage pasted on it elastically deform, which achieves the buffering effect of the perforated plate, and the technical effect of eliminating the sudden change in tension caused by the vibration of the steel wire rope in the transmission process, and finally achieving an accurate calculation of the hoist The purpose of the load.

Description of the drawings

Figure 1 is a three-dimensional schematic diagram of the present invention installed on a wire rope tension automatic balance suspension device;

Figure 2 is a cross-sectional view of the sensor of the present invention;

Figure 3 is a schematic diagram of the structure of the perforated plate in the present invention;

Figure 4 is a schematic diagram of the structure of the perforated plate sound absorber;

Figure 5 is an equivalent circuit diagram of Figure 4;

Figure 6 is an equivalent circuit diagram of the sensor;

Figure 7 is the wire rope tension change curve during the ascending process of the cage

Figure 8 is the wire rope tension change curve during the downward process of the cage;

Figure 9 is the tension change curve of the 2# wire rope for three descending strokes;

Figure 10 is the curve of the wire rope tension change measured by the oil pressure sensor during the lifting process;

Figure 11 is the curve of the wire rope tension measured by the universal pressure block sensor during the lifting process.

In the picture: 1. Sensor body, 2. Base, 3. End cover, 4. Balance cylinder, 5. Piston rod, 6, Groove, 7, Step blind hole, 8. Strain gauge, 9, Wire channel, 10. Cylindrical oil cavity, 11, strain beam, 12, flat oil cavity, 13, support seat, 14, slider, 15, cantilever beam, 16, perforated plate, 17, rigid plate, 18, micro-hole, 19, Red copper sealing gasket, 20, C-shaped groove, 21, middle plate, 22, side plate, 23, oil injection channel.

Detailed ways

The present invention will be further explained below.

As shown in Figs. 1 to 3, a pressure sensor for load weighing of a mine multi-rope hoist includes a sensor body 1. The sensor body 1 includes a base 2 and an end cover 3 mounted on the base 2. The cross section of the end cover 3 is in the shape of an inverted convex, and its upper end surface is provided with a groove 6 that matches the piston rod 5 of the balance cylinder 4, and the end cover 3 below the groove 6 is provided with a stepped blind hole 7; the end cover 3 is opened There is a wire channel 9 intersecting with the step blind hole 7; a cylindrical oil cavity 10 is coaxially opened below the step blind hole 7, and the lower end of the cylindrical oil cavity 10 penetrates the bottom of the end cover 3, and the upper end of the cylindrical oil cavity 10 is connected to the step blind The gap between the lower end surfaces of the hole forms a strain beam 11, and the strain gauge 8 is attached to the upper surface of the strain beam 11;

The cross-section of the base 2 is in a concave shape, and the upper part of the inner side of the groove on the upper end face is threaded with the upper part of the outer periphery of the boss on the lower end face of the end cap 3. The space between the upper end of the groove and the lower end of the boss forms a flat oil cavity 12; on the base 2 There is an oil injection channel 23 intersecting with the flat oil cavity 12; the lower end support 13 of the base 2 is installed in the groove opened on the slider 14 of the balance oil cylinder 4; between the lower part of the flat oil cavity 12 and the support 13 The part is the cantilever beam 15;

The cylindrical oil cavity 10 and the flat oil cavity 12 together form a closed oil cavity;

The cylindrical oil cavity 10 is embedded with a perforated plate 16, and the perforated plate 16) includes a rigid plate body 17 and a plurality of micro-holes 18 opened on the rigid plate body 17, the outer circumference of the rigid plate body 17 and The inner wall of the cylindrical oil cavity 10 near the lower end is tightly fitted;

The cylindrical oil cavity 10 and the flat oil cavity 12 are communicated with each other through a micro hole 18.

Preferably, the thickness of the perforated plate 16 is 1 mm, the diameter of the micro holes 18 is 1.4 mm, the distance between the micro holes 18 is 3.5 mm, and the distance between the upper end surface of the perforated plate 16 and the top of the cylindrical oil cavity 10 is 7 mm.

In order to improve the sealing performance of the oil cavity 12, a copper sealing gasket 19 is provided at the threaded fitting position between the groove of the base 2 and the boss of the end cover 3.

To ensure sufficient strain of the strain beam, the bottom diameter of the stepped blind hole 7 is greater than the diameter of the cylindrical oil cavity 10.

In order to ensure that the cantilever beam 15 can be fully deformed when the end cover 3 is subjected to the positive pressure of the piston rod 5 of the balancing oil cylinder 4, and at the same time, it can avoid stress concentration leading to the failure of the sensor, a C-shaped groove 20 is provided on the outer periphery of the support base 13. Among them, the C-shaped groove 20 is matched with the upper end of the groove of the slider 14.

To ensure that the strain gauge 8 accurately transmits the strain signal, the strain gauge 8 is a circular strain gauge with a diameter slightly smaller than the bottom diameter of the stepped blind hole 7.

The sensor 1 is installed in the elevator wire rope tension automatic balance suspension device. The upper end of the tension automatic balance device is the lifting end, which is connected to the wire rope, and the lower end is the load end, which is connected to the lifting container; the middle plate 21 and the side plate 22 pass through the balancing cylinder 4 and The sliding blocks 14 together form a pull-out buckle structure. The diameter of the groove on the upper end of the end cover 3 is slightly larger than the diameter of the piston rod 5, which is adapted to the piston rod 5 and bears the positive pressure P on the piston rod 5. The positive pressure P is transmitted to the base 2 through the end cover 3. 2 The support base 13 whose bottom is matched with the slider 14 bears the support reaction force P'generated by the slider 14, and the cantilever beam 15 of the base 2 produces bending deformation under the combined action of the positive pressure P and the support reaction force P', so that The volume of the oil cavity changes, resulting in oil pressure inside the oil cavity. The pressurized oil flows from the flat oil cavity 12 through the multiple micro-holes 18 opened on the perforated plate 16 and squeezes into the cylindrical oil cavity 10, and The strain beam 11 on the top of the cylindrical oil chamber 10 is deformed, and the output electric signal of the strain gage 8 attached to the strain beam 11 is transmitted to the upper computer by the wire, so that the tension of each wire rope is measured, and the upper computer can be processed and converted. Get the total load raised by the hoist. Since the pressure sensor is provided with a perforated plate between the flat oil cavity and the cylindrical oil cavity, the potential energy contained in the pressure oil flowing through the perforated plate is fully dissipated by the reciprocating friction with the micro-holes, and finally passes through the squeeze sensor The strain beam makes the strain gage pasted on it elastically deform, which achieves the buffering effect of the perforated plate, and the technical effect of eliminating the sudden change in tension caused by the vibration of the steel wire rope in the transmission process, and finally achieving an accurate calculation of the hoist The purpose of the load.

Regarding the technical effect that the perforated plate in this application can achieve that the sudden change in tension of the steel wire rope due to vibration can be eliminated during the transmission process, the test and analysis contents are as follows:

The sound absorption structure of the perforated plate is composed of micropores and a rigid cavity, and its structure is shown in Figure 4. In the figure, p is the sound pressure incident perpendicular to the perforated plate, b is the hole spacing, d is the hole diameter, t is the thickness of the orifice plate, and h is the depth of the cavity behind the plate. In order to explain the elimination principle of the perforated plate structure on the tension mutation caused by the vibration of the steel wire rope, this experiment takes the perforated plate sound-absorbing structure on its internal sound wave absorption effect as the research object.

In order to study the vibration laws of system mechanics or acoustics, researchers usually draw the mechanical or acoustic circuit diagrams of the system by analogy with the circuit diagrams in electricity. Here, the perforated plate can be regarded as an acoustic element with acoustic resistance and sound quality, and together with the back cavity, it forms a resonance sound absorber. The components in the resonant sound absorber can be analogous to impedance-type electrical components such as resistance and inductance. The equivalent circuit is shown in Figure 5. In the figure, ρc is the characteristic impedance of the fluid, R is the equivalent acoustic resistance of the perforated plate, M is the equivalent acoustic mass of the perforated plate, and Z _h is the acoustic impedance rate of the cavity behind the plate.

Since the perforated plate is a porous thin-walled structure, the sound propagation in each hole and the interaction between the holes are very complicated, so the acoustic impedance ratio is usually used to express the acoustic characteristics of the perforated element. The acoustic impedance rate of the perforated plate can be expressed as:

Z=R+jωM (1)

Its relative acoustic impedance ratio is:

In the formula, q is the perforation rate of the perforated plate (the ratio of the area of the perforated part to the total area), r is the relative acoustic resistance, ω is the angular frequency of the incident sound wave, and m is the relative sound quality. among them:

In the formula, μ is the viscosity coefficient of the fluid, c ₀ is the speed of sound in the fluid, k _r is the acoustic resistance constant, k _{m is the} sound quality constant, and k is the perforated plate constant.

In the formula, ρ ₀ is the density of the fluid, and η is the shear viscosity coefficient of the fluid.

The acoustic impedance ratio of the cavity behind the perforated plate is:

Z _h =-j cot(ωh/c ₀ ) (6)

The sound absorption characteristics of the sound-absorbing structure of the perforated plate can be obtained from its equivalent circuit. The sound absorption coefficient of the perforated plate when the sound wave is incident perpendicularly is:

The sound absorption coefficient α reaches its maximum at resonance:

From equation (7), we know that the resonance frequency f ₀ should make the following equation hold:

ω ₀ m-cot(ω ₀ h/c ₀ )=0 (9)

Solve equation (9) with an approximate method, and the obtained resonance frequency is:

According to the related knowledge of electric-force-acoustic analogy, the equivalent circuit diagram of the entire oil cavity structure is shown in Figure 6. In the figure, S represents the force area of the cantilever beam. First, analyze the mechanical system and draw a line of force from the external force. When the line of force reaches the cantilever beam mass M _m , it is divided into three branches, which are balanced with three forces: one passes through M _m and balances with the inertial force, the other The branch is balanced with the damping force, and the other is balanced with the elastic force, so the mass M _m , the force resistance R _m and the force C _m are connected in series in the drawn impedance type mechanical circuit diagram. After analyzing the acoustic part, the sound streamline generated by the vibration of the cantilever beam starts from the cantilever beam. One part changes the mass of the liquid in the flat cavity (C _a1 ), and the other part also causes the liquid in the small holes of the perforated plate to move. , So the streamline will branch here, one passing through the flat cavity contributes to the sound volume C _a1 ending in the rigid cavity wall, and the other passing through the perforated plate (the sound quality is _Ma1 , the sound resistance is R _a1 ), Then the acoustic volume _Ca2 contributed through the cylindrical cavity ends at the rigid wall. It can be seen from the circuit diagram that when the oil in the oil cavity of the sensor vibrates, the acoustic resistance R _{a1 of the} perforated plate divides the pressure of the branch where it is located, avoiding the voltage across the cylindrical cavity (C _a2 ) of the branch If it is too large, the vibration energy contained when the oil enters the cylindrical oil cavity has been weakened.

Based on the above analysis, the pressure sensor with a built-in perforated plate structure in the oil cavity of the present application can effectively reduce the impact of vibration on the output signal of the change area, and therefore can be used for accurate measurement of the tension of the hoist wire rope.

In order to test the performance of the sensor designed in this application, the calibrated sensor was applied to the Gaozhuang Coal Mine to collect the tension of the wire rope of the auxiliary shaft hoist. The test plan adopted is as follows: first, repeat the measurement of the tension of the 1# and 2# wire ropes during the three complete strokes of the hoist (ascending and descending process); then install the sensor on the 2# wire rope to the corresponding position of the 3# wire rope, Repeatedly measure the tension of the 1# and 3# wire ropes in three complete strokes; the test cage (wide cage) has been in an empty state. After the experimental equipment is installed and debugged according to the system scheme, the tension of different wire ropes in different strokes can be measured.

Figure 7 shows the tension comparison curve of 1#, 2# and 3# wire ropes with different strokes during the ascending process of the cage. It can be seen from the figure that with the operation of the hoisting system, the wire rope tension has an overall increasing trend, and the tension change trend of the three wire ropes is basically the same. In the initial acceleration phase (0-5s), due to the short lifting distance in this section, the quality of the tail rope changes less, and the wire rope tension increases slowly; when the cage enters the main acceleration phase (5-20s), the acceleration will increase. Therefore, it is reflected in the figure that the tension of the steel wire rope will also undergo abrupt changes; after the acceleration stabilizes (20-21s), the tension value will increase steadily; when the cage enters the uniform speed stage (21-22s), the acceleration decreases to 0m/s ² , at this time, the wire rope tension will have a decreasing amount of sudden change; then the cage enters the uniform rising stage (22-45s), at this stage the wire rope tension increases linearly with time; when the system enters the main deceleration stage (45- 50s), because the acceleration is negative at this time, the tension will suddenly decrease; then as the cage continues to rise (50-60s), the suspension length of the tail rope continues to increase, so the tension value shows an increase immediately after the decrease General trend; when the system enters the crawling phase (60-65s), the acceleration again suddenly changes to 0m/s ² , causing the tension value to appear a sudden increase first and then slowly increase; when the cage enters the final deceleration phase (65- After 73s), because the remaining lifting distance is shorter and the crawling speed of the cage is slow, the amount of change in the tension of the steel rope is relatively small.

Figure 8 shows the comparison curve of wire rope tension of different strokes 1#, 2# and 3# during the downward process of the cage. When the cage moves downward, the overall tension change trend is opposite to that when it moves upward. It can be seen from the figure that in the initial acceleration phase (0-5s), the wire rope tension decreases slowly; when entering the main acceleration phase (5-20s), because the cage acceleration suddenly increases, it will be reflected on the tension curve. A downward sudden change occurs; when the acceleration stabilizes (20-21s), the tension value decreases steadily; when the cage enters the uniform speed phase (21-22s), the acceleration suddenly decreases to 0m/s ² , and the tension value increases. Large sudden change; when the cage drops at a constant speed (22-46s), the wire rope tension decreases linearly with time; when the system enters the main deceleration phase (46-48s), the acceleration suddenly changes to a negative value, which is reflected in the tension curve A sudden increase will occur; but then as the cage continues to drop (48-60s), the suspension length of the tail rope continues to decrease, so the tension value continues to decrease after the sudden increase; when the cage enters the crawling stage (60 -66s), because the acceleration becomes 0m/s ² again, there will be a sudden change in the tension value; when the cage enters the final deceleration stage (66-73s), the remaining lifting distance is short and the cage running speed It is slow, so the change in the tension value of the wire rope in this section is small.

Figure 9 is the tension comparison curve of 2# steel wire rope in three descending strokes. It can be seen from the figure that although the original measurement signal contains a small amount of noise due to external interference, the overall trend of the curve is consistent with the actual situation, and the measurement results of the three descending strokes almost completely overlap, which again verifies all The design sensor has good stability.

The above qualitative analysis of the change trend of the wire rope tension with the running time verifies the accuracy of the signal measured by the pressure sensor with vibration reduction function designed in this application. Regarding the accuracy of the measured signal, it can be explained from another angle. For the auxiliary shaft hoist of Gaozhuang Coal Mine, there are a total of 2 tail ropes suspended at the bottom of the cage with a density of 8.65 kg/m. The length of the tail rope from the wellhead to the bottom of the well is 253m deep, so the weight of the tail rope changes approximately It is 4.4 tons. Theoretically, when the same cage is located at the wellhead and bottom of the well, the change in the load of the wire rope should be equal to the weight of the tail rope, that is, the change in the tension of the wire rope when the cage is at the well head and bottom is equal to the weight of the tail rope. It can be seen from Figure 7 and Figure 8 that the change in tension of each wire rope from the driving position to the parking position is about 1.15 tons, and the total tension change of the four wire ropes is 4.6 tons. This result is approximately equal to the theoretical result, so it can be considered that the designed sensor can accurately characterize the tension value of the wire rope. Later, if the pressure sensor designed in this application is installed between each piston rod and the slider of the cage automatic balancing device, the tension value of the four steel wire ropes can be accurately measured, and the load of the hoist can be weighed.

The comparison and analysis of the measurement of steel wire rope tension in this application and the traditional measurement method are as follows:

In order to realize the online monitoring of hoist wire rope tension, Gaozhuang Coal Mine has successively adopted two measurement schemes: oil pressure sensor to measure oil pressure and general pressure block sensor to measure pressure. In order to verify the superiority of the pressure sensor in this application, this application compares and analyzes the wire rope tension data measured by the two previous solutions.

(1) Oil pressure sensor measurement scheme

The oil pressure method to measure the tension of the wire rope is realized by installing an oil pressure sensor on the balance oil circuit of the wire rope tension automatic balance suspension device to measure the oil pressure in the oil cylinder. When the friction between the piston rod of the balance cylinder and the inner wall of the cylinder is ignored, the product of the oil pressure and the piston area is the tension value of the wire rope.

Taking the hoisting process as an example, for 1# steel wire rope, the steel wire rope tension change curve calculated by using the oil pressure sensor output oil pressure value is shown in Figure 10. It can be seen from the figure that the overall tension value shows an upward trend, which is consistent with the actual situation that the suspension length of the tail rope under the cage is increasing, and the violent fluctuation of the tension data only occurs in the final parking stage. However, the tension value in the figure often keeps a fixed value within a certain lifting distance, which leads to a significant step change in the tension curve. When the balance cylinder is leveled, the oil pressure in the balance cylinder corresponding to the steel wire rope with lower tension will increase, but at the beginning of leveling, the hydraulic pressure in the cylinder is not enough to overcome the friction between the piston rod and the cylinder wall Therefore, although the oil pressure will gradually increase, the movement state of the piston rod will not change. When the oil pressure is enough to overcome the friction, the piston rod will extend outward, and the extension of the piston rod will cause the cylinder The internal oil volume suddenly increases and the oil pressure value suddenly decreases, so the wire rope tension curve will have a step change.

Therefore, when the oil pressure measured by the oil pressure sensor is used to calculate the wire rope tension, due to the uncertainty of the friction between the piston rod and the inner wall of the oil cylinder during the leveling process of the balance cylinder, the tension curve will respond slowly and the data will change stepwise. The application of this method cannot meet the requirement of accurately measuring the tension of each steel wire rope of a multi-rope hoist.

(2) General pressure block sensor measurement scheme

The general pressure block sensor is a pressure sensor without any damping measures. In this measurement method, a pressure sensor is installed between the piston rod and the sliding block of the tension automatic balance suspension device, and the electric signal output after the pressure sensor is deformed under pressure is used to calculate the tension of the steel wire rope. Figure 11 shows the wire rope tension curve measured by the general briquetting sensor in the auxiliary shaft of Gaozhuang Coal Mine during a certain lifting of the cage. It can be seen from the figure that the tension curve of the steel wire rope measured by the pressure block sensor without any damping measures for a single wire rope fluctuates very sharply, and its amplitude change is the largest even up to 4.5 tons in a short time. In practice, the maximum loading capacity of the cage is only 14 tons. Therefore, the wire rope tension value measured by adding the general pressure block sensors does not reflect the actual loading capacity of the cage. Therefore, the scheme of measuring pressure by using a general pressure block sensor is also not suitable for real-time monitoring of wire rope tension of a multi-rope hoist.

By comparing the tension curves measured by the above two methods, it can be seen that the tension signal calculated with the output signal of the pressure sensor does not have the measurement data level caused by the uncertainty of the friction between the piston rod and the cylinder during the oil pressure measurement. The situation of sudden changes, and at the same time, it greatly alleviates the large fluctuation of the measurement result of the general pressure block sensor due to the absence of any internal vibration reduction measures, so it can be used for accurate measurement of the wire rope tension, thereby improving the judgment of the staff Provide an accurate reference for whether the machine is overloaded.

Claims (6)

1. A pressure sensor for load weighing of a mine multi-rope hoist, comprising a sensor body (1). The sensor body (1) comprises a base (2) and an end cover (3) installed on the base (2) , The end cover (3) has an inverted convex shape in cross section, and its upper end is provided with a groove (6) that matches the piston rod (5) of the balance cylinder (4), and the end cover (3) below the groove (6) ) A stepped blind hole (7) is provided inside; the end cover (3) is provided with a wire channel (9) intersecting with the stepped blind hole (7); a cylindrical oil cavity is coaxially opened under the stepped blind hole (7) (10), the lower end of the cylindrical oil chamber (10) penetrates the bottom of the end cover (3), the gap between the upper end of the cylindrical oil chamber (10) and the lower end surface of the stepped blind hole forms a strain beam (11), a strain beam (11) ) Strain gauge (8) is attached to the upper surface;

   The cross section of the base (2) is in a concave shape, and the upper part of the inner side of the groove on the upper end face is matched with the upper part of the outer circumference of the boss on the lower end face of the end cap (3). The space between the upper end face of the groove and the lower end face of the boss forms a flat oil cavity ( 12); The base (2) is provided with an oil injection channel (23) intersecting with the flat oil cavity (12); the lower support seat (13) of the base (2) is installed on the slider (14) of the balance cylinder (4) ) In the groove; the part between the lower part of the flat oil cavity (12) and the support seat (13) is a cantilever beam (15);

   The cylindrical oil cavity (10) and the flat oil cavity (12) together form a closed oil cavity;

   It is characterized in that, the cylindrical oil cavity (10) is embedded with a perforated plate (16), and the perforated plate (16) includes a rigid plate body (17) and a plurality of holes arranged on the rigid plate body (17). A micro-hole (18), the outer circumference of the rigid plate body (17) closely fits with the inner wall of the cylindrical oil cavity (10) near the lower end;

   The cylindrical oil cavity (10) and the flat oil cavity (12) are communicated with each other through a micro hole (18).
2. The pressure sensor for load weighing of a mine multi-rope hoist according to claim 1, wherein the thickness of the perforated plate (16) is 1mm, the diameter of the microhole (18) is 1.4mm, The distance between the holes (18) is 3.5mm, and the distance between the upper end surface of the perforated plate (16) and the top of the cylindrical oil cavity (10) is 7mm.
3. A pressure sensor for load weighing of a mine multi-rope hoist according to claim 1 or 2, wherein the groove of the base (2) and the threaded fitting position of the boss of the end cover (3) It is provided with a red copper sealing gasket (19).
4. The pressure sensor for load weighing of a mine multi-rope hoist according to claim 3, characterized in that the bottom diameter of the stepped blind hole (7) is greater than the diameter of the cylindrical oil cavity (10).
5. A pressure sensor for load weighing of a mine multi-rope hoist according to claim 4, characterized in that the outer circumference of the support base (13) is provided with a C-shaped groove (20), and a C-shaped groove (20) ) Is matched with the upper end of the groove of the sliding block (14).
6. The pressure sensor for load weighing of a mine multi-rope hoist according to claim 5, wherein the strain gauge (8) is a circular shape with a diameter slightly smaller than the bottom diameter of the step blind hole (7) Strain gauges.

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