A stroke position detection component for a cylinder driver of a hot runner

Abstract

The invention relates to the technical field of detection devices, and discloses a stroke position detection component of a cylinder driver for a hot runner, comprising a displacement detection device and a cylinder, wherein the movement of a piston in the cylinder controls the movement of a valve needle in a mold, an uneven stepped protrusion is present on the top of the piston, the displacement detection device is arranged and fixed above the outside of the cylinder, an outer ring ultrasonic transmitter and an inner ring ultrasonic transmitter arranged in the displacement detection device are used to detect the distance between pistons in multiple cylinders, and the measurement error of the outer ring ultrasonic transmitter is greater than the measurement error of the inner ring ultrasonic transmitter, the position where the inner ring ultrasonic transmitter is arranged corresponds to the position of the protrusion on the piston, a scattering layer is provided between the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter and the cylinder, a crystal medium is provided in the scattering layer, the grains in the crystal medium are small and arranged in an orderly manner, and the sound waves emitted by the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter first pass through the crystal medium and then penetrate into the cylinder.

Description

Technical Field

[0001] The invention relates to the technical field of detection devices, in particular to a stroke position detection component of a cylinder driver for a hot runner. Background Art

[0002] Hot runner systems are heating component systems used in injection molds to inject melted plastic particles into the mold cavity. Hot runner molds are a new structure that heats the runners and runners of traditional molds or three-plate molds, so that the runners and runners do not need to be removed each time they are formed. By setting heating rods and heating rings near or in the center of the runners, the entire runner from the nozzle outlet of the injection molding machine to the gate is in a high temperature state, so that the plastic in the runner remains molten. After stopping the machine, it is generally not necessary to open the runner to remove the condensate. When restarting the machine, it is only necessary to heat the runner to the required temperature. Hot runner technology is widely used in various fields that require injection molding, such as automobile manufacturing, electronic manufacturing, and medical device manufacturing. In automobile manufacturing, hot runner technology can be used for injection molding of parts such as headlights, dashboards, and door panels. In electronic manufacturing, it can be used for injection molding of parts such as TV shells and mobile phone shells. In addition, hot runner technology also plays an important role in medical device manufacturing, such as injection molding of handles, shells, and other parts. With the continuous development of injection molding technology, hot runner technology is also constantly innovating and improving. For example, the emergence of needle valve hot runners has further improved the accuracy and reliability of hot runner technology. At the same time, hot runner technology is also developing in a more intelligent and automated direction to meet the needs of modern manufacturing.

[0003] In a needle valve hot runner, the needle valve position is usually controlled by a cylinder. The hot runner cylinder usually works in complex environments such as high temperature and high pressure, and the overall structure is compact. When detecting the actuator stroke position in the cylinder, an ultrasonic displacement sensor is required, and the inside of the cylinder is detected from the outside. However, the structure in the cylinder is complex, and the piston is not a flat surface, but has certain protrusions, which can easily cause errors in the detection process. Summary of the invention

[0004] (I) Technical problems to be solved: In view of the deficiencies of the prior art, the present invention provides a stroke position detection component for a cylinder driver of a hot runner, which has the advantages of high-precision and low-cost detection and solves the problem of interference from the internal structure of the cylinder.

[0005] (II) Technical solution: To achieve the above-mentioned purpose of high-precision and low-cost detection, the present invention provides the following technical solution: A stroke position detection component for a cylinder driver of a hot runner, comprising a displacement detection device and a cylinder, wherein the cylinder is arranged in a hot runner mold, and a piston is arranged in the cylinder, and the piston controls the movement of a valve needle in the mold by moving, and an uneven stepped protrusion is present on the top of the piston, and the displacement detection device is arranged and fixed above the outside of the cylinder and is in close contact with the cylinder, and an outer ring ultrasonic transmitter and an inner ring ultrasonic transmitter arranged in the displacement detection device are used to detect the distance of the piston in the cylinder, and the measurement error of the outer ring ultrasonic transmitter is greater than the measurement error of the inner ring ultrasonic transmitter, and the position where the inner ring ultrasonic transmitter is arranged corresponds to the position of the protrusion on the piston, and a scattering layer is arranged between the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter and the cylinder, and a crystal medium is arranged in the scattering layer, and the grains in the crystal medium are small and arranged in an orderly manner, and the sound waves emitted by the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter first pass through the crystal medium and then penetrate into the cylinder.

[0006] During detection, a weighted sum is performed based on the error coefficients of the outer and inner ring ultrasonic transmitters and their measurement results, and the measurement result of the inner ring ultrasonic transmitter needs to be subtracted from the value of the stepped protrusion inside the piston to obtain the position of the piston in the cylinder. When the piston moves, the above process is repeated to obtain the displacement distance.

[0007] Preferably, the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter are arranged in a ring array on the displacement detection device, and each ultrasonic transmitter in the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter is arranged at intervals.

[0008] Preferably, a scattering layer track is provided in the displacement detection device, the scattering layer is arranged in the scattering layer track, the displacement detection device and the scattering layer are in the form of disks, and the scattering layer can rotate in the scattering layer track.

[0009] Preferably, the scattering layer is composed of a crystal medium and a turntable frame, the crystal medium is in a fan-shaped sheet shape, and a slot for inserting the crystal medium is provided in the turntable frame, and the crystal medium is assembled by pushing it into the slot.

[0010] Preferably, the turntable frame is arranged at intervals corresponding to the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter, and grid holes are provided at the intervals. By rotating the scattering layer, the ultrasonic waves emitted by the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter can not pass through the crystal medium.

[0011] Preferably, the crystal medium is made of quartz, and the interior of the turntable frame is filled with foam board or other sound insulation materials.

[0012] Preferably, the side surface of the turntable frame is provided with texture.

[0013] (III) Beneficial effects: Compared with the prior art, the present invention provides a stroke position detection component for a cylinder driver of a hot runner, which has the following beneficial effects: 1. The stroke position detection component for a cylinder driver of a hot runner realizes dual detection of the displacement of the piston in the cylinder by setting an inner ring ultrasonic transmitter and an outer ring ultrasonic transmitter. The inner ring ultrasonic transmitter accurately measures the position of the protrusion on the piston, effectively reducing the measurement error caused by the uneven surface of the piston (such as stepped protrusions). Although the outer ring ultrasonic transmitter has a large error, it provides additional data points for correction and verification. By using the Kalman filter principle, the error coefficients and measurement results of the two transmitters are combined for weighted summation, which significantly improves the overall detection efficiency. Measurement accuracy. In order to solve the problem of uneven piston in the cylinder, two circles of ultrasonic transmitters are set up. At the same time, the principle of Kalman filter is used to reduce the cost of the equipment and ensure its own detection accuracy. A scattering layer is also provided at the lower end of the displacement detection device. The scattering layer is provided with crystal medium and grid holes. When the cylinder to be detected is relatively long and the displacement is large, the scattering layer is moved so that the ultrasonic waves emitted by the outer circle ultrasonic transmitter and the inner circle ultrasonic transmitter are first transmitted to the cylinder through the crystal medium. The grains in the crystal medium are small and neatly arranged. The difference in the shape of the grains will lead to different grain boundary orientation and distribution, which will further affect the propagation path of the ultrasonic wave. For example, the grains of castings are generally coarse and irregular in shape, while those of rolled parts will be irregular during processing and forging. The internal grains are crushed and stretched in the streamline direction. When the grains are arranged in an orderly manner, the propagation path of the ultrasonic wave may be more regular, and the reflection and scattering phenomena are relatively less. After the sound wave passes through the crystal medium, due to its orderly structure and high sound speed, it can be more effectively focused and guided. When the sound wave enters the cylinder from the crystal medium layer, although it will be affected by the change of the medium, the crystal medium has provided a relatively stable and concentrated propagation path for the sound wave. The structure inside the crystal medium layer is highly ordered, and the scattering and attenuation of the sound wave in it are relatively small. In contrast, when passing directly through the cylinder, the sound wave may be scattered by the irregular structure inside the cylinder (such as surface roughness, internal defects, etc.), resulting in the dispersion and attenuation of the sound wave energy. Due to the focusing and guiding effect of the crystal medium on the sound waves, as well as the effect of reducing scattering and attenuation, when the sound waves pass through the crystal medium layer and then through the cylinder, the signal-to-noise ratio (that is, the ratio of useful signal to noise) will be relatively high, which helps to capture the target signal more clearly during the detection process. Due to the focusing and guiding effect of the crystal medium on the sound waves, as well as the effect of reducing scattering and attenuation, when the sound waves pass through the crystal medium and then through the cylinder, they can be more accurately located in the target area, thereby improving the accuracy of detection. The crystal medium has a certain amplification effect on the sound waves and can enhance the intensity of the sound waves, which helps to capture weak signals more easily during the detection process and improve the sensitivity of detection. By reducing scattering and attenuation and improving the directionality of the sound waves, the crystal medium layer can significantly improve the signal-to-noise ratio.Reduce the impact of noise on the test results and improve the reliability and stability of the test.

[0014] 2. The stroke position detection component of the cylinder driver for the hot runner is arranged in a circular array on the displacement detection device through an outer ring ultrasonic transmitter and an inner ring ultrasonic transmitter, and each ultrasonic transmitter in the outer ring ultrasonic transmitter and the inner ring ultrasonic transmitter is arranged at intervals. The design of the circular array enables the ultrasonic wave to measure the piston in the cylinder from multiple angles and positions. This multi-angle measurement method can effectively reduce the measurement error caused by the uneven surface or complex shape of the piston. Each ultrasonic transmitter is arranged at intervals, which means that during the measurement process, multiple independent data points will be collected and analyzed, which increases the redundancy of the data, so that the system can more accurately judge the true position of the piston. The multiple ultrasonic transmitters in the circular array can They work simultaneously to form a relatively uniform ultrasonic field. This design helps to reduce the interference of the external environment (such as airflow, temperature, etc.) on the measurement results of a single ultrasonic transmitter. The circular array and the spaced ultrasonic transmitters provide more possibilities for data processing and algorithm optimization. The system can use the correlation between multiple data points to further improve the measurement accuracy and stability. In addition, this design also helps to realize more complex algorithms and data processing technologies, such as multi-sensor data fusion, Kalman filtering, etc., to further improve the performance and accuracy of the system. The design of the circular array enables the displacement detection device to cover a wider measurement range. Whether it is a small or large movement of the piston, the system can effectively measure and track it.

[0015] 3. The stroke position detection component of the cylinder driver for the hot runner can rotate in the scattering layer track through the scattering layer. This design enables the displacement detection device to flexibly adjust the working mode according to actual needs. When the structure of the cylinder is relatively simple and regular, and the propagation path of the sound wave therein is clear, the ultrasonic wave can be directly passed through the cylinder for detection by rotating the scattering layer, without the need for additional crystal media for focusing and guiding, thereby simplifying the detection process and improving the detection efficiency. The fan-shaped sheet design and replaceability of the crystal medium enable the displacement detection device to be optimized for cylinders of different shapes and sizes. By selecting a suitable crystal medium, it can be more Effectively focus and guide ultrasonic waves, reduce scattering and attenuation, thereby improving detection accuracy and stability. The crystal medium is assembled by pushing it into the slot of the turntable frame. This design makes the replacement of the crystal medium simple and quick. When the crystal medium needs to be replaced due to long-term use or damage, there is no need to disassemble the entire displacement detection device, which greatly reduces maintenance costs and complexity. The rotating design of the scattering layer and the replaceability of the crystal medium provide convenience for the subsequent expansion and upgrade of the displacement detection device. With the increase in cylinder types and the continuous changes in detection requirements, new detection requirements can be met by adding or replacing different types of crystal media without replacing the entire displacement detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the cylinder structure of the present invention Figure 1 .

[0017] Figure 2 Schematic diagram of the cylinder structure of the present invention Figure 2 .

[0018] Figure 3 It is a schematic diagram of the structure of the displacement detection device of the present invention.

[0019] Figure 4 It is a schematic diagram of the scattering layer structure of the present invention.

[0020] Figure 5 It is a schematic cross-sectional view of the piston of the present invention.

[0021] Figure 6 It is a working schematic diagram of the displacement detection device of the present invention.

[0022] Figure 7 It is a schematic diagram of the notch of the turntable frame of the present invention.

[0023] In the figure: 1, displacement detection device; 2, cylinder; 11, outer ring ultrasonic transmitter; 12, inner ring ultrasonic transmitter; 13, scattering layer; 14, scattering layer track; 21, piston; 131, crystal medium; 132, grid hole; 133, turntable frame; 1331, notch. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-Figure 6 , a stroke position detection component of a cylinder driver for a hot runner, comprising a displacement detection device 1 and a cylinder 2, wherein the cylinder 2 is arranged in a hot runner mold, and the movement of a piston 21 in the cylinder 2 controls the movement of a valve needle in the mold, and an uneven stepped protrusion exists on the top of the piston 21, and the displacement detection device 1 is arranged and fixed above the cylinder 2 and is in close contact with the cylinder 2, and an outer ring ultrasonic transmitter 11 and an inner ring ultrasonic transmitter 12 arranged in the displacement detection device 1 are used to detect the distance of the piston 21 in the cylinder 2, and the outer ring ultrasonic transmitter 12 is used to detect the distance of the piston 21 in the cylinder 2. The measurement error of the outer ring ultrasonic transmitter 11 is greater than the measurement error of the inner ring ultrasonic transmitter 12. The position at which the inner ring ultrasonic transmitter 12 is arranged corresponds to the raised position on the piston 21. A scattering layer 13 is provided between the outer ring ultrasonic transmitter 11, the inner ring ultrasonic transmitter 12 and the cylinder 2. A crystal medium 131 is provided in the scattering layer 13. The grains in the crystal medium 131 are small and arranged in an orderly manner. The sound waves emitted by the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 first pass through the crystal medium 131 and then penetrate into the cylinder 2.

[0026] The worker fixes the displacement detection device 1 above the cylinder. The displacement detection device 1 is provided with an outer ring ultrasonic transmitter 11 and an inner ring ultrasonic transmitter 12. Because there may be a stepped protrusion on the upper surface of the piston 21 in the cylinder 2, a double-ring ultrasonic transmitter is provided to avoid detection errors. At the same time, the detection error of the outer ring ultrasonic transmitter 11 is greater than the detection error of the inner ring ultrasonic transmitter 12. According to the error coefficients of the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 and their measurement results, a weighted sum is performed, that is, the Kalman filter principle. The measurement result of the outer ring ultrasonic transmitter 11 is , and the measurement accuracy is , the measurement result of the inner ring ultrasonic transmitter 12 is , and the measurement accuracy is , the expression of Kalman estimation equation is: , where K is the Kalman gain coefficient, which is calculated as: , substitute its own error coefficient into the calculation, so that the measuring instrument with larger error and the measuring instrument with smaller error are used in time for calculation, which can also achieve the effect of reducing error. While improving the measurement accuracy, the production cost and maintenance cost are greatly reduced. Before the inner ring ultrasonic transmitter 12 measures, it is necessary to input the value of the stepped protrusion of the piston 21 in the cylinder 2. In this way, the detection not only avoids the error caused by the unevenness of the piston 21 in the cylinder 2, but also improves its own accuracy through the Kalman filter principle. The detection device of the outer ring ultrasonic transmitter 11 adopts a lower precision detection device to reduce the cost. A scattering layer 13 is also provided at the lower end of the displacement detection device 1. The scattering layer 13 is provided with a crystal medium 131 and a grid hole 132. When the cylinder 2 to be detected is relatively long as a whole and the displacement is large, the scattering layer 13 is moved so that the ultrasonic waves emitted by the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 are first transmitted to the cylinder 2 through the crystal medium 131. The grains in the crystal medium 131 are small and neatly arranged. The shape difference of the grains will lead to the direction and The difference in distribution affects the propagation path of the ultrasonic wave. For example, the grains of a casting are generally coarse and irregular in shape, while the internal grains of a rolled part will be crushed and elongated in the direction of the processing and forging streamline. When the grains are arranged in an orderly manner, the propagation path of the ultrasonic wave may be more regular, and the reflection and scattering phenomena are relatively less. After the sound wave passes through the crystal medium 131, due to its orderly structure and high sound speed, it can focus and guide the sound wave more effectively. When the sound wave enters the cylinder from the crystal medium 131, although it will be affected by the change of the medium, the crystal medium 131 has provided a relatively stable and concentrated propagation path for the sound wave, making the transmission of the ultrasonic wave more directional, avoiding the increase of errors caused by scattering and causing deviations in the stop position of the valve needle controlled by the cylinder 2. Due to the focusing and guiding effect of the crystal medium layer on the sound wave, as well as the effect of reducing scattering and attenuation, when the sound wave passes through the crystal medium layer and then through the cylinder, its signal-to-noise ratio (i.e., the ratio of useful signal to noise) will be relatively high, which helps to capture the target signal more clearly during the detection process.

[0027] The outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 are arranged in a circular array on the displacement detection device 1, and each ultrasonic transmitter in the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 is arranged at intervals. The design of the circular array enables the ultrasonic wave to measure the piston 21 in the cylinder 2 from multiple angles and positions. This multi-angle measurement method can effectively reduce the measurement error caused by the uneven surface or complex shape of the piston 21. Each ultrasonic transmitter is arranged at intervals, which means that during the measurement process, multiple independent data points will be collected and analyzed, which increases the redundancy of the data, so that the system can more accurately judge. The actual position of the piston 21 is determined by the annular array. Multiple ultrasonic transmitters in the annular array can work simultaneously to form a relatively uniform ultrasonic field. This design helps to reduce the interference of the external environment (such as airflow, temperature, etc.) on the measurement results of a single ultrasonic transmitter. The annular array and the spaced ultrasonic transmitters provide more possibilities for data processing and algorithm optimization. The system can use the correlation between multiple data points to further improve the measurement accuracy and stability. In addition, this design also helps to realize more complex algorithms and data processing technologies, such as multi-sensor data fusion, Kalman filtering, etc., to further improve the performance and accuracy of the system.

[0028] The displacement detection device 1 is provided with a scattering layer track 14, the scattering layer 13 is arranged in the scattering layer track 14, and the displacement detection device 1 and the scattering layer 13 are in the form of disks, and the scattering layer 13 can rotate in the scattering layer track 14, the scattering layer 13 is composed of a crystal medium 131 and a turntable frame 133, the crystal medium 131 is in the form of a fan-shaped sheet, and the turntable frame 133 is provided with a slot 1331 for inserting the crystal medium 131, see Figure 7 The crystal medium 131 is assembled by pushing it into the slot 1331, so that the crystal medium 131 can be replaced. The turntable frame 133 is arranged at intervals corresponding to the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12, and a grid hole 132 is provided at the interval position, see Figure 4 By rotating the scattering layer 13, the ultrasonic waves emitted by the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 can be prevented from passing through the crystal medium 131. When the detection speed needs to be increased, or when the structure of the cylinder is relatively simple and regular, the propagation path of the sound wave therein is relatively clear, and the scattering and attenuation are relatively small. At this time, directly passing through the cylinder for detection can more accurately obtain the displacement information of the piston without the need for additional crystal medium 131 for focusing and guiding.

[0029] The crystal medium 131 is made of quartz, a common single crystal material with high hardness, high light transmittance and good chemical stability, and is suitable for optical and acoustic applications. Single crystal material is a typical representative of small grains and highly ordered arrangement. In a single crystal, all grains are fused into a continuous crystal structure with no interface between grains, so the grains are naturally "small" and highly ordered. The turntable frame 133 is filled with sound insulation materials such as foam boards, and the side of the turntable frame 133 is provided with textures.

[0030] Working Principle: Hot runner mold is a new structure that heats the runner and channel of traditional mold or three-plate mold, so that there is no need to remove the runner and runner during each forming process. By setting heating rods and heating rings near or in the center of the runner, the entire runner from the nozzle outlet of the injection molding machine to the gate is in a high temperature state, so that the plastic in the runner remains molten. After shutdown, it is generally not necessary to open the runner to remove the condensate. When restarting, it is only necessary to heat the runner to the required temperature. The overall structure of the hot runner mold is compact, and the valve needle controlled by the cylinder 2 is also located inside the mold. It is difficult to detect the displacement of the piston 21 inside the cylinder 2, so it is necessary to set an ultrasonic detector to detect the displacement of the internal piston 21 from the outside. The worker fixes the displacement detection device 1 above the cylinder, and the displacement detection The device 1 is provided with an outer ring ultrasonic transmitter 11 and an inner ring ultrasonic transmitter 12. Because there may be a stepped protrusion on the upper surface of the piston 21 in the cylinder 2, a double-ring ultrasonic transmitter is provided to avoid detection errors. At the same time, the detection error of the outer ring ultrasonic transmitter 11 is greater than the detection error of the inner ring ultrasonic transmitter 12. A weighted sum is performed based on the error coefficients of the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 and their measurement results, that is, the Kalman filter principle. Before the inner ring ultrasonic transmitter 12 measures, it is necessary to input the value of the stepped protrusion of the piston 21 in the cylinder 2. In this way, the detection not only avoids the error caused by the unevenness of the piston 21 in the cylinder 2, but also improves the detection accuracy through the Kalman filter principle, and The outer ring ultrasonic transmitter 11 adopts a detection device with lower precision, which reduces the cost. A scattering layer 13 is also provided at the lower end of the displacement detection device 1. The scattering layer 13 is provided with a crystal medium 131 and a grid hole 132. When the cylinder 2 to be detected is relatively long as a whole and has a large displacement, the scattering layer 13 is moved so that the ultrasonic waves emitted by the outer ring ultrasonic transmitter 11 and the inner ring ultrasonic transmitter 12 are first transmitted to the cylinder 2 through the crystal medium 131. The crystal grains in the crystal medium 131 are small and neatly arranged. The difference in the shape of the crystal grains will lead to different grain boundary orientations and distributions, thereby affecting the propagation path of the ultrasonic wave. For example, the crystal grains of the casting are generally coarse and irregular in shape, while the rolled parts will crush the internal crystal grains in the direction of the processing and forging streamlines and When the crystal grains are arranged in an orderly manner, the propagation path of the ultrasonic wave may be more regular, and the reflection and scattering phenomena are relatively less. After the sound wave passes through the crystal medium 131, due to its orderly structure and high sound speed, it can focus and guide the sound wave more effectively. When the sound wave enters the cylinder from the crystal medium 131, although it will be affected by the change of the medium, the crystal medium 131 has provided a relatively stable and concentrated propagation path for the sound wave, making the transmission of the ultrasonic wave more directional, avoiding the increase of the error caused by scattering and causing the deviation of the stop position of the valve needle controlled by the cylinder 2. It is like setting up a fence at the gate for queuing. Due to the focusing and guiding effect of the crystal medium layer on the sound wave, and the effect of reducing scattering and attenuation,When the sound wave passes through the crystal medium layer and then through the cylinder, its signal-to-noise ratio (i.e. the ratio of useful signal to noise) will be relatively high, which helps to capture the target signal more clearly during the detection process.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A stroke position detection assembly for a cylinder driver of a hot runner, comprising a displacement detection device (1) and a cylinder (2), wherein the cylinder (2) is arranged in a hot runner mold, and a piston (21) is arranged in the cylinder (2), and the piston (21) controls the movement of a valve needle in the mold by moving, and an uneven stepped protrusion is present on the top of the piston (21), characterized in that: The displacement detection device (1) is arranged and fixed above the outside of the cylinder (2) and is in close contact with the cylinder (2). The outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) provided in the displacement detection device (1) are used to detect the distance of the piston (21) in the cylinder (2). The measurement error of the outer ring ultrasonic transmitter (11) is greater than the measurement error of the inner ring ultrasonic transmitter (12). The position of the inner ring ultrasonic transmitter (12) corresponds to the raised position on the piston (21). A scattering layer (13) is provided between the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) and the cylinder (2). A crystal medium (131) is provided in the layer (13), and the crystal grains in the crystal medium (131) are small and orderly arranged. The sound waves emitted by the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) first pass through the crystal medium (131) and then penetrate into the cylinder (2). During detection, a weighted sum is performed based on the error coefficients of the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) and their measurement results, and the measurement result of the inner ring ultrasonic transmitter (12) needs to be subtracted from the value of the stepped protrusion inside the piston (21), so as to obtain the position of the piston (21) in the cylinder (2). When the piston (21) moves, the above process is repeated to obtain the displacement distance.

2. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 1, characterized in that: The outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) are arranged in a ring array on the displacement detection device (1), and each ultrasonic transmitter in the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) are arranged at intervals.

3. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 2, characterized in that: The displacement detection device (1) is provided with a scattering layer track (14), the scattering layer (13) is arranged in the scattering layer track (14), the displacement detection device (1) and the scattering layer (13) are in the form of circular disks, and the scattering layer (13) can rotate in the scattering layer track (14).

4. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 3, characterized in that: The scattering layer (13) is composed of a crystal medium (131) and a turntable frame (133); the crystal medium (131) is in the form of a fan-shaped sheet; a notch (1331) for inserting the crystal medium (131) is provided in the turntable frame (133); the crystal medium (131) is assembled by pushing it into the notch (1331).

5. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 4, characterized in that: The turntable frame (133) is arranged at intervals corresponding to the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12), and grid holes (132) are provided at the intervals. By rotating the scattering layer (13), the ultrasonic waves emitted by the outer ring ultrasonic transmitter (11) and the inner ring ultrasonic transmitter (12) do not pass through the crystal medium (131).

6. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 4, characterized in that: The crystal medium (131) is made of quartz, and the interior of the turntable frame (133) is filled with foam plates.

7. The stroke position detection assembly of a cylinder driver for a hot runner according to claim 4, characterized in that: The side surface of the turntable frame (133) is provided with patterns.

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