Hydraulic cylinder with pressure measuring function and pressure measuring method

Abstract

The invention provides a hydraulic cylinder with a pressure measuring function and a pressure measuring method, and relates to the field of hydraulic cylinders. The hydraulic cylinder comprises a cylinder body containing liquid and a piston pushed by the liquid and moving in the cylinder body, and further comprises a signal generator which is static relative to the cylinder body and used for transmitting and receiving a first signal wave passing through the liquid to a target point static relative to the cylinder body when the piston moves to any position; the timer is used for recording the propagation time of the first signal wave; and the data processor is used for calculating the propagation speed of the first signal wave according to the distance between the signal generator and the target point and the propagation time, and matching the propagation speed of the first signal wave with a preset propagation speed and pressure mapping relation to obtain target pressure. According to the scheme, measurement of the pressure in the hydraulic cylinder can be achieved by means of the single-beam first signal wave, the number of needed devices is small, the measurement space and the measurement cost are greatly saved, and high measurement precision is achieved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinders, and more particularly to a hydraulic cylinder with pressure measurement function and a pressure measurement method. Background Technology

[0002] Pressure measurement of hydraulic cylinders is a crucial step in hydraulic system testing. Accurately measuring the pressure within the hydraulic cylinder ensures it operates normally according to its design parameters and provides a basis for analyzing system faults. The fluid within the hydraulic cylinder is constantly in motion, causing continuous changes in fluid pressure. Accurately measuring these pressure changes is essential for ensuring the proper functioning of the hydraulic system.

[0003] Currently, common pressure measurement methods in existing technologies typically require the use of pressure sensors or pressure transmitters. The measurement principle involves converting pressure signals into electrical signals to measure liquid pressure. However, this method has the following drawbacks: Firstly, most electrical pressure sensors have poor environmental adaptability; certain high-temperature or high-humidity environments may affect their performance or cause damage. The complex environment inside a hydraulic cylinder places high demands on electrical pressure sensors, and using such sensors for pressure measurement is costly. Secondly, most existing pressure measurement sensors are large in size, while the space inside a hydraulic cylinder is limited. Large sensors are not only inconvenient to install but also affect the movement of the liquid, thus requiring urgent improvement. Summary of the Invention

[0004] This invention provides a hydraulic cylinder with pressure measurement function and a pressure measurement method to solve the defects of hydraulic cylinder pressure measurement in the prior art, realize pressure measurement by using the propagation speed of a first signal wave in a liquid medium, simplify the pressure measurement structure, and reduce the pressure measurement cost.

[0005] According to a first aspect of the present invention, a hydraulic cylinder with pressure measurement function is provided, the hydraulic cylinder comprising a cylinder body containing a liquid and a piston pushed by the liquid and moving within the cylinder body, the hydraulic cylinder further comprising: A signal generator, which is stationary relative to the cylinder, is used to transmit and receive a first signal wave passing through the liquid to a target point that is stationary relative to the cylinder when the piston moves to any position. A timer, the timer being used to record the propagation time of the first signal wave; A data processor is configured to calculate the propagation speed of the first signal wave based on the distance between the signal generator and the target point and the propagation time, and to match the propagation speed of the first signal wave with a preset propagation speed-pressure mapping relationship to obtain the target pressure.

[0006] According to the present invention, in a hydraulic cylinder with pressure measurement function, the signal generator is fixed on the cylinder end cap, and the target point is set on the cylinder side wall.

[0007] According to the present invention, a hydraulic cylinder with pressure measurement function has a first protrusion parallel to the cylinder end cover at a predetermined distance from the cylinder end cover on the side wall of the cylinder body. The first protrusion is located between the piston and the cylinder end cover, and the target point is set on the first protrusion.

[0008] According to the present invention, in a hydraulic cylinder with pressure measurement function, the signal generator is fixed on the side wall of the cylinder body, and the target point is set on the end cap of the cylinder body.

[0009] According to the present invention, a hydraulic cylinder with pressure measurement function has a second protrusion parallel to the cylinder end cover at a predetermined distance from the cylinder end cover on the side wall of the cylinder body. The second protrusion is located between the piston and the cylinder end cover, and the signal generator is fixed on the second protrusion.

[0010] According to the present invention, in a hydraulic cylinder with pressure measurement function, the signal generator is fixed on the side wall of the cylinder body, and the target point is set on the side wall of the cylinder body.

[0011] According to the present invention, in a hydraulic cylinder with pressure measurement function, the distance between the signal generator and the cylinder end cap does not exceed a preset length.

[0012] According to the hydraulic cylinder with pressure measurement function of the present invention, the preset propagation speed and pressure mapping relationship is expressed as follows: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a pressure correction factor corresponding to the liquid inside the cylinder. This is the preset temperature corresponding to the liquid inside the cylinder.

[0013] According to the hydraulic cylinder with pressure measurement function of the present invention, the hydraulic cylinder further includes a temperature sensor, which is fixed on the cylinder end cap or cylinder side wall and in contact with the liquid. The temperature sensor is used to measure the temperature of the liquid medium when the first signal propagates.

[0014] According to the hydraulic cylinder with pressure measurement function of the present invention, the preset propagation speed and pressure mapping relationship is expressed as follows: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a pressure correction factor corresponding to the liquid inside the cylinder. The measured value is from the temperature sensor. This is a temperature correction factor corresponding to the liquid inside the cylinder. This is a preset constant.

[0015] According to the hydraulic cylinder with pressure measurement function of the present invention, the first signal wave is parallel to the axis of the cylinder body.

[0016] According to the hydraulic cylinder with pressure measurement function of the present invention, the signal generator is also used to emit and receive a second signal wave passing through the liquid when the piston moves to any position; The timer is also used to record the propagation time of the second signal wave; The data processor is also used to calculate the displacement of the piston relative to the cylinder based on the propagation time of the second signal wave and the propagation speed of the first signal wave.

[0017] According to the present invention, in a hydraulic cylinder with pressure measurement function, the first signal wave is perpendicular to the axis of the cylinder body.

[0018] According to the hydraulic cylinder with pressure measurement function of the present invention, the first signal wave and the second signal wave are any one of millimeter wave signal, ultrasonic signal, and electromagnetic wave.

[0019] According to the present invention, the hydraulic cylinder with pressure measurement function is a hydraulic oil, water, or emulsion.

[0020] According to a second aspect of the present invention, the present invention also provides a pressure measurement method, the method being applied to the hydraulic cylinder with pressure measurement function described above, the method comprising: It transmits and receives the first signal wave that passes through the liquid at the target point; Record the propagation time of the first signal wave; The propagation speed is calculated based on the distance between the signal generator and the target point and the propagation time of the first signal wave; The target pressure is obtained by matching the propagation speed of the first signal wave with the preset propagation speed and pressure mapping relationship.

[0021] This invention provides a hydraulic cylinder with pressure measurement function. By selecting a fixed target point on the cylinder body, a signal generator transmits and receives a first signal wave to the target point. Then, a timer is used to time the transmission time of the first signal wave. Next, a data processor calculates the propagation speed of the first signal wave. Finally, the target pressure is determined using the propagation speed and a preset propagation speed-pressure mapping relationship. The pressure inside the hydraulic cylinder can be measured using a single first signal wave, requiring fewer components, which greatly saves measurement space and measurement cost. In addition, the preset propagation speed-pressure mapping relationship built into the data processor can accurately map the propagation speed to pressure, resulting in high measurement accuracy.

[0022] In addition, the pressure measurement method provided by this invention can also achieve the above-mentioned technical effects, which will not be described in detail here. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a hydraulic cylinder with pressure measurement function provided by the present invention.

[0025] Figure 2 This is one of the schematic diagrams of the pressure measurement principle provided by the present invention.

[0026] Figure 3 This is a schematic diagram showing the target point provided by the present invention located on the side wall of the cylinder.

[0027] Figure 4 This is a schematic diagram of the target point provided by the present invention being set on the protrusion of the cylinder side wall.

[0028] Figure 5 This is one of the schematic diagrams of the signal generator provided by the present invention fixed to the side wall of the cylinder.

[0029] Figure 6 This is a schematic diagram of the signal generator provided by the present invention fixed to the protrusion on the side wall of the cylinder.

[0030] Figure 7 This is the second schematic diagram of the signal generator provided by the present invention fixed on the side wall of the cylinder.

[0031] Figure 8 This is the second schematic diagram of the pressure measurement principle provided by the present invention.

[0032] Figure 9This is a schematic diagram of the temperature sensor provided by the present invention fixed on the side wall of the cylinder.

[0033] Figure 10 This is a schematic diagram of the temperature sensor provided by the present invention fixed to the cylinder end cover.

[0034] Figure 11 This is a schematic diagram of the displacement measurement principle provided by the present invention.

[0035] Explanation of reference numerals in the attached figures: 110: Liquid; 120: Cylinder block; 121: Cylinder end cap; 122: Cylinder sidewall; 123: First protrusion; 124: Second protrusion; 130: Piston; 140: Signal generator; 150: Temperature sensor. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0037] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0038] The following is combined Figures 1 to 11 This invention describes a hydraulic cylinder with pressure measurement function and a pressure measurement method.

[0039] Figure 1 This is a schematic diagram of a hydraulic cylinder with pressure measurement function provided by the present invention. Please refer to it. Figure 1 As shown, this embodiment provides a hydraulic cylinder with pressure measurement function. The hydraulic cylinder includes a cylinder body 120 containing liquid 110 and a piston 130 that is pushed by the liquid 110 and moves within the cylinder body 120. The hydraulic cylinder also includes a signal generator 140, a timer, and a data processor. The following will describe each of the above parts in detail: A signal generator 140, which is stationary relative to the cylinder 120, is used to transmit and receive a first signal wave passing through the liquid 110 to a target point that is stationary relative to the cylinder 120 when the piston 130 moves to any position.

[0040] In practical implementation, the signal generator 140 can be installed inside the liquid-containing cavity, thus preventing the signal generator 140 from moving relative to the cylinder 120. Alternatively, the signal generator 140 can be installed outside the liquid-containing cavity; it can be fixed to the outside of the cylinder 120 or secured by other auxiliary fasteners, ensuring the signal generator 140 remains stationary relative to the cylinder 120. The component where the target point is located is the fixed target object. This fixed target object can be the cylinder end cap or the cylinder sidewall. In practical implementation, the selection of the target point and the fixing point of the signal generator can be flexibly set according to the propagation requirements of the first signal wave, as long as the first signal wave passes through the liquid medium. Furthermore, the number of reflections of the first signal wave can be one or multiple. In practical implementation, to simplify the measurement structure, it is preferable that the first signal wave undergoes only one reflection.

[0041] A timer, used to record the propagation time of the first signal wave.

[0042] In this embodiment, the timer is a device for measuring time. There are many ways to implement a timer; it can be a simple mechanical device or a complex electronic device. The appropriate implementation depends on the required accuracy, functionality, and application scenario. Timer implementation methods include, but are not limited to, implementing a timer interrupt through programming, using the built-in timer of an MCU to achieve complex timing, or using a counter in an electronic circuit to convert the time into actual time, such as a 555 timer or a counter / timer module within a microcontroller. In this embodiment, the time recorded by the timer starts from the transmission of the first signal wave and stops when the first signal wave is reflected and received.

[0043] It should be noted that since the timer needs to detect the transmission time of the first signal wave emitted by the signal generator, the timer and the signal generator can be installed close to each other. When the signal generator is installed inside the cylinder, the timer is installed inside the cylinder and connected to the signal generator. When the signal generator is installed outside the cylinder, the timer is installed outside the cylinder and connected to the signal generator.

[0044] The data processor is used to calculate the propagation speed of the first signal wave based on the distance between the signal generator 140 and the target point and the propagation time, and to match the propagation speed of the first signal wave with a preset propagation speed-pressure mapping relationship to obtain the target pressure.

[0045] In this embodiment, the data processor is a processor capable of performing data operations, typically referring to a device with the ability to perform mathematical and logical operations. These processors can be hardware or software-defined, and include, but are not limited to, central processing units (CPUs), programmable logic controllers (PLCs), microcontrollers (MCUs), and system-on-a-chip (SoCs). It should be noted that since the data processor needs to reprocess the data collected by the timer, it needs to be connected to the timer. The installation location of the data processor can be referenced to the timer.

[0046] In this embodiment, Figure 2 This is one of the schematic diagrams of the pressure measurement principle provided by the present invention. Please refer to it. Figure 2 As shown, since the signal generator 140 and the target point are relatively stationary, the distance between them is fixed. The propagation path of the first signal wave is back and forth between them. Therefore, the total propagation distance of the signal can be calculated using the distance between them. The data processor can obtain the propagation speed by calculating the ratio of the total distance to the propagation time. The preset propagation speed-pressure mapping relationship refers to the pre-set correspondence between propagation speed and pressure. This mapping relationship can be linear or nonlinear, continuous or discrete, with propagation speed as the independent variable and pressure as the dependent variable. It should be noted that... Figure 2 Although the measurement principle used is ultrasound, this pressure measurement principle is also applicable to other primary signal waves such as electromagnetic waves and millimeter waves. Figure 2 The ultrasonic wave in the signal can be replaced with other first signal waves that are equally applicable to this principle.

[0047] The hydraulic cylinder with pressure measurement function in this embodiment selects a fixed target point on the cylinder body, uses a signal generator to transmit and receive a first signal wave to the target point, then uses a timer to time the transmission time of the first signal wave, then uses a data processor to calculate the propagation speed of the first signal wave, and finally uses the propagation speed and a preset propagation speed-pressure mapping relationship to determine the target pressure. The pressure inside the hydraulic cylinder can be measured with a single beam of first signal wave, requiring fewer components, which greatly saves measurement space and measurement cost. In addition, the preset propagation speed-pressure mapping relationship built into the data processor can accurately map the propagation speed to pressure, with high measurement accuracy.

[0048] In some possible implementations, the signal generator 140 is fixed to the cylinder end cap 121, and the target point is set on the cylinder side wall 122.

[0049] Figure 3This is a schematic diagram showing the target point set on the side wall of the cylinder block, as provided by the present invention. Please refer to it. Figure 3 As shown, the signal generator 140 is fixed to the cylinder end cover 121, and the target point is set on the cylinder side wall 122. At this time, the first signal wave generated by the signal generator 140 travels back and forth between the cylinder side wall 122 and the cylinder end cover 121. In the specific implementation process, it is only necessary to store the distance between the two in the data processor in advance, and the data processor can calculate the total transmission distance of the first signal wave.

[0050] The hydraulic cylinder with pressure measurement function in this embodiment uses a signal generator fixed by the cylinder end cover and sets the target point on the side wall of the cylinder. Pressure measurement can be achieved without modifying the hydraulic cylinder, which has good versatility. In addition, this method does not require adding devices to the side wall of the cylinder, which has little impact on the piston movement.

[0051] In some possible implementations, a first protrusion 123 parallel to the cylinder end cover 121 is formed on the cylinder sidewall 122 at a predetermined length from the cylinder end cover 121. The first protrusion 123 is located between the piston 130 and the cylinder end cover 121, and the target point is set on the first protrusion 123.

[0052] Figure 4 This is a schematic diagram showing the target point provided by the present invention set on the protrusion of the cylinder side wall. Please refer to it. Figure 4 As shown, the signal generator 140 is fixed to the cylinder end cover 121, and the target point is set on the first protrusion 123 on the cylinder side wall 122. At this time, the first signal wave generated by the signal generator 140 travels back and forth between the first protrusion 123 and the cylinder end cover 121. In the specific implementation process, it is only necessary to store the distance between the two in the data processor in advance, and the data processor can calculate the total transmission distance of the first signal wave.

[0053] The hydraulic cylinder with pressure measurement function in this embodiment has a protruding structure inside the cylinder body, and the target point is set on the protruding structure, which makes it easier to measure the distance between the signal generator and the target point. In addition, since the position of the protrusion is restricted to a specific position, the piston will not affect the transmission of the first signal wave, which can improve the stability of pressure measurement.

[0054] In some possible implementations, the signal generator 140 is fixed to the cylinder sidewall 122, and the target point is set on the cylinder end cap 121.

[0055] Figure 5 This is one of the schematic diagrams of the signal generator provided by the present invention fixed to the side wall of the cylinder. Please refer to it. Figure 5As shown, the signal generator 140 is fixed on the cylinder side wall 122, and the target point is set on the cylinder end cover 121. At this time, the first signal wave generated by the signal generator 140 travels back and forth between the cylinder side wall 122 and the cylinder end cover 121. In the specific implementation process, it is only necessary to store the distance between the two in the data processor in advance, and the data processor can calculate the total transmission distance of the first signal wave.

[0056] The hydraulic cylinder with pressure measurement function in this embodiment uses a signal generator fixed on the side wall of the cylinder body and sets the target point on the cylinder end cover, which improves the utilization rate of the internal space of the cylinder body.

[0057] In some possible implementations, a second protrusion 124 parallel to the cylinder end cover 121 is formed on the cylinder sidewall 122 at a predetermined length from the cylinder end cover 121. The second protrusion 124 is located between the piston 130 and the cylinder end cover 121, and the signal generator 140 is fixed on the second protrusion 124.

[0058] Figure 6 This is a schematic diagram of the signal generator provided by the present invention fixed to the protrusion on the side wall of the cylinder. Please refer to it. Figure 6 As shown, unlike directly fixing the signal generator 140 to the side wall of the cylinder, this embodiment adds a second protrusion 124 to the side wall of the cylinder near the end cap. This second protrusion can provide the signal generator with an installation position closer to the inside of the liquid medium.

[0059] The hydraulic cylinder with pressure measurement function in this embodiment has a protruding structure inside the cylinder body, which is used to fix the signal generator, making it easier to fix the signal generator.

[0060] In some possible implementations, the signal generator 140 is fixed to the cylinder block sidewall 122, and the target point is set on the cylinder block sidewall 122.

[0061] Figure 7 This is the second schematic diagram of the signal generator provided by this invention fixed to the side wall of the cylinder. Please refer to it. Figure 7 As shown, since the first signal wave emitted by the signal generator 140 needs to pass through the liquid medium, the target point and the signal generator should be set on the opposite surface of the cylinder sidewall. Usually, since the cylinder is cylindrical, in order to simplify the calculation of the propagation path in the specific implementation process, any diameter on the cylindrical cross section can be selected as a reference, and the signal generator 140 and the target point can be set at the two ends of the diameter respectively.

[0062] In some possible implementations, where the signal generator and the target point are not on the same component in the foregoing embodiments, the first signal wave is parallel to the axis of the cylinder 120.

[0063] In some possible implementations, where the signal generator and the target point are not on the same component in the foregoing embodiments, the first signal wave is perpendicular to the axis of the cylinder 120.

[0064] In some possible implementations, the distance between the signal generator 140 and the cylinder end cap 121 does not exceed a preset length.

[0065] The hydraulic cylinder with pressure measurement function in this embodiment, by setting a signal generator and a target point on the opposite side of the cylinder body sidewall, makes the propagation path of the first signal wave richer on the one hand, and occupies less space in the piston movement direction on the other hand, which is suitable for hydraulic cylinders with a large piston movement range.

[0066] In some possible implementations, the preset propagation speed and pressure mapping relationship is expressed as: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a pressure correction factor corresponding to the liquid inside the cylinder. The measured value is from the temperature sensor. This is a temperature correction factor corresponding to the liquid inside the cylinder. This is a preset constant.

[0067] It should be noted that the parameters and parameters The values ​​are all related to the medium inside the cylinder; different liquid media correspond to different parameter values. In practical implementation, the specific parameter values ​​can be determined by measuring the propagation velocity of various liquid media under different pressures under experimental conditions and using data fitting. In practical implementation, for cases where high precision is not required, it is not necessary to distinguish between liquid media; the parameters can be determined by combining extensive data analysis during the implementation process. The value can be 4.9187, parameter The value can be 1362.68.

[0068] In some possible implementations, the hydraulic cylinder further includes a temperature sensor 150, which is fixed to the cylinder end cap 121 or the cylinder side wall 122 and in contact with the liquid 110. The temperature sensor 150 is used to measure the temperature of the liquid 110 medium when the first signal propagates.

[0069] Figure 8 This is the second schematic diagram of the pressure measurement principle provided by the present invention. Please refer to it. Figure 8As shown, unlike the previous embodiment, this embodiment adds a temperature sensor. This temperature sensor can measure the temperature of the liquid medium in real time. When converting propagation velocity into pressure, the influence of temperature needs to be considered. This method can further improve the accuracy of pressure measurement. It should be noted that... Figure 8 Although the measurement principle used is ultrasound, this pressure measurement principle is also applicable to other primary signal waves such as electromagnetic waves and millimeter waves. Figure 8 The ultrasonic wave in the signal can be replaced with other first signal waves that are equally applicable to this principle.

[0070] It should be noted that since the transmission of the first signal wave is not instantaneous, while the temperature sensor can typically complete the measurement instantaneously, in practice, the temperature sensor can measure the temperature value at any point between the transmission of the first signal wave and its reflection and reception. Preferably, for further accuracy, multiple temperature measurements can be performed during the transmission of the first signal wave, and the optimal temperature value can be determined by taking the average or median temperature. In practice, the number of temperature measurements can be adjusted according to the required pressure measurement accuracy. For example, when relatively high pressure measurement accuracy is required, the number of temperature measurements can be set relatively high; when relatively low pressure measurement accuracy is required, the number of temperature measurements can be set relatively low.

[0071] In practical implementation, the temperature sensor 150 can be fixed to the cylinder end cover 121, such as... Figure 9 As shown, the temperature sensor 150 can also be fixed to the cylinder side wall 121, such as... Figure 10 As shown

[0072] In some possible implementations, the preset propagation speed and pressure mapping relationship is expressed as: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a preset correction coefficient corresponding to the liquid 110 inside the cylinder 120. The reading is the value measured by temperature sensor 150.

[0073] The hydraulic cylinder with pressure measurement function in this embodiment uses a linear relationship to represent the relationship between propagation speed and pressure. Various media only need to be measured once under experimental conditions. It can accurately convert the propagation speed into the pressure value of the liquid in the cylinder, which has high accuracy. Moreover, the operation logic is simple and does not consume too many computing resources, which helps to improve the processing speed of the data processor.

[0074] In some possible implementations, the signal generator is also used to emit and receive a second signal wave passing through the liquid when the piston moves to any position; The timer is also used to record the propagation time of the second signal wave; The data processor is also used to calculate the displacement of the piston relative to the cylinder based on the propagation time of the second signal wave and the propagation speed of the first signal wave.

[0075] Please refer to Figure 11 As shown, for ease of understanding, this embodiment takes the signal generator being mounted on the cylinder end cap as an example. Signal 1 is emitted from the end cap, reflected by a target point on a fixed object, and then returns to the end cap. Based on the propagation path and propagation time of signal 1, the data processor can calculate the propagation speed of signal 1. Since signal 1 and signal 2 have the same properties and propagation environment, the propagation speed of signal 1 can be equivalent to the propagation speed of signal 2. Since the propagation path of signal 2 is emitted from the cylinder end cap, reflected by the piston, and then returns to the end cap, the propagation stroke of signal 2 can be calculated using the propagation speed of signal 1 and the propagation time of signal 2. Based on the installation position of the signal generator, the displacement of the piston relative to the end cap is equal to half of the propagation stroke of signal 2, therefore the displacement of the piston can be measured. It should be noted that the second signal wave is not limited to being emitted from the cylinder end cap towards the piston. In specific implementations, the principle of displacement measurement is similar when the signal generator is located on a side wall or protrusion, and therefore will not be elaborated here.

[0076] The hydraulic cylinder with pressure measurement function in this embodiment not only uses signal waves to complete pressure measurement, but also uses another signal wave directed at the piston to realize piston displacement measurement, which combines pressure and temperature measurement. At the same time, it can share some components, which greatly saves measurement space and makes the parameter detection of the hydraulic cylinder more comprehensive.

[0077] In some possible implementations, the first signal wave and the second signal wave are any one of millimeter wave signals, ultrasonic signals, and electromagnetic waves.

[0078] The hydraulic cylinder with pressure measurement function in this embodiment can use any one of millimeter wave signals, ultrasonic signals, or electromagnetic waves as the transmission object. The generation and control of such signal waves are relatively convenient and suitable for various liquid media.

[0079] Preferably, in the specific implementation process, when ultrasonic signals are used as the transmission object, in order to ensure measurement accuracy and the performance of the time wave, the transducer can be used to emit ultrasonic waves with a frequency between 0.02MHz and 500MHz.

[0080] In some possible implementations, the liquid is hydraulic oil, water, or an emulsion.

[0081] The hydraulic cylinder with pressure measurement function in this embodiment is suitable for hydraulic cylinders using any single medium, such as hydraulic oil, water, or emulsion. These media cover most existing hydraulic cylinder products, thus exhibiting good versatility.

[0082] The pressure measurement method provided by the present invention is described below. The pressure measurement method described below can be referred to in correspondence with the hydraulic cylinder with pressure measurement function described above.

[0083] According to another aspect of the present invention, this embodiment provides a pressure measurement method, which is applied to the hydraulic cylinder with pressure measurement function described in the above embodiments.

[0084] The hydraulic cylinder includes a cylinder body containing liquid and a piston that is pushed by the liquid and moves within the cylinder body. The hydraulic cylinder further includes: a signal generator, which is stationary relative to the cylinder body, for transmitting and receiving a first signal wave passing through the liquid towards a target point stationary relative to the cylinder body when the piston moves to any position; a timer, which records the propagation time of the first signal wave; and a data processor, which calculates the propagation speed of the first signal wave based on the distance between the signal generator and the target point and the propagation time, and matches the propagation speed of the first signal wave with a preset propagation speed-pressure mapping relationship to obtain a target pressure.

[0085] The pressure measurement method includes the following steps: It transmits and receives the first signal wave that passes through the liquid at the target point; Record the propagation time of the first signal wave; The propagation speed is calculated based on the distance between the signal generator and the target point and the propagation time of the first signal wave; The target pressure is obtained by matching the propagation speed of the first signal wave with the preset propagation speed and pressure mapping relationship.

[0086] The pressure measurement method in this embodiment selects a fixed target point on the cylinder body, uses a signal generator to transmit and receive a first signal wave to the target point, then uses a timer to time the transmission time of the first signal wave, then uses a data processor to calculate the propagation speed of the first signal wave, and finally uses the propagation speed and a preset propagation speed-pressure mapping relationship to determine the target pressure. The pressure inside the hydraulic cylinder can be measured with a single beam of first signal wave, requiring fewer components, which greatly saves measurement space and measurement cost. In addition, the preset propagation speed-pressure mapping relationship built into the data processor can accurately map the propagation speed to pressure, with high measurement accuracy.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic cylinder with pressure measurement function, characterized in that, The hydraulic cylinder includes a cylinder body containing liquid and a piston that is pushed by the liquid and moves within the cylinder body. The hydraulic cylinder also includes: A signal generator, which is stationary relative to the cylinder, is used to transmit and receive a first signal wave passing through the liquid to a target point that is stationary relative to the cylinder when the piston moves to any position. A timer, the timer being used to record the propagation time of the first signal wave; A data processor is configured to calculate the propagation speed of the first signal wave based on the distance between the signal generator and the target point and the propagation time, and to match the propagation speed of the first signal wave with a preset propagation speed-pressure mapping relationship to obtain the target pressure.

2. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The signal generator is fixed on the cylinder end cap, and the target point is set on the cylinder side wall.

3. The hydraulic cylinder with pressure measurement function according to claim 2, characterized in that, A first protrusion parallel to the cylinder end cover is formed on the side wall of the cylinder body at a predetermined distance from the cylinder end cover. The first protrusion is located between the piston and the cylinder end cover, and the target point is set on the first protrusion.

4. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The signal generator is fixed on the side wall of the cylinder, and the target point is set on the end cover of the cylinder.

5. The hydraulic cylinder with pressure measurement function according to claim 4, characterized in that, A second protrusion parallel to the cylinder end cover is formed on the side wall of the cylinder body at a predetermined distance from the cylinder end cover. The second protrusion is located between the piston and the cylinder end cover, and the signal generator is fixed on the second protrusion.

6. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The signal generator is fixed on the side wall of the cylinder, and the target point is set on the side wall of the cylinder.

7. The hydraulic cylinder with pressure measurement function according to claim 6, characterized in that, The distance between the signal generator and the cylinder end cap does not exceed a preset length.

8. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The preset propagation speed and pressure mapping relationship is expressed as follows: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a pressure correction factor corresponding to the liquid inside the cylinder. This is the preset temperature corresponding to the liquid inside the cylinder.

9. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The hydraulic cylinder also includes a temperature sensor, which is fixed to the cylinder end cap or cylinder side wall and in contact with the liquid. The temperature sensor is used to measure the temperature of the liquid medium when the first signal propagates.

10. The hydraulic cylinder with pressure measurement function according to claim 9, characterized in that, The preset propagation speed and pressure mapping relationship is expressed as follows: ; In the formula, Indicates the speed of propagation. Indicates pressure, This is a pressure correction factor corresponding to the liquid inside the cylinder. The measured value is from the temperature sensor. This is a temperature correction factor corresponding to the liquid inside the cylinder. This is a preset constant.

11. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The signal generator is also used to emit and receive a second signal wave passing through the liquid when the piston moves to any position; The timer is also used to record the propagation time of the second signal wave; The data processor is also used to calculate the displacement of the piston relative to the cylinder based on the propagation time of the second signal wave and the propagation speed of the first signal wave.

12. The hydraulic cylinder with pressure measurement function according to claim 3 or 5, characterized in that, The first signal wave is parallel to the axis of the cylinder.

13. The hydraulic cylinder with pressure measurement function according to claim 6 or 7, characterized in that, The first signal wave is perpendicular to the axis of the cylinder.

14. The hydraulic cylinder with pressure measurement function according to claim 11, characterized in that, Both the first signal wave and the second signal wave are any one of millimeter wave signals, ultrasonic signals, and electromagnetic waves.

15. The hydraulic cylinder with pressure measurement function according to claim 1, characterized in that, The liquid is hydraulic oil, water, or emulsion.

16. A pressure measurement method, characterized in that, The method is applied to a hydraulic cylinder with pressure measurement function as described in any one of claims 1 to 14, and the method includes: It transmits and receives the first signal wave that passes through the liquid at the target point; Record the propagation time of the first signal wave; The propagation speed is calculated based on the distance between the signal generator and the target point and the propagation time of the first signal wave; The target pressure is obtained by matching the propagation speed of the first signal wave with the preset propagation speed and pressure mapping relationship.

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