Linear motor rated thrust measuring device

Abstract

The utility model belongs to the technical field of linear motor measurement, and particularly relates to a linear motor rated thrust measuring device. The utility model provides a linear motor rated thrust measuring device which comprises a test platform and a sliding plate in sliding fit with the test platform. The to-be-tested linear motor is fixed on the test platform and drives the sliding plate to slide; the test platform is also provided with a fixed block, and the fixed block is in threaded connection with a push rod which can be adjusted along the sliding direction of the sliding plate. A force sensor is further arranged on the sliding plate and located in the extending direction of the push rod, and the detection end of the force sensor right faces the thrust end of the push rod. The linear motor rated thrust measuring device further comprises a control unit which can be electrically connected with the linear motor to be measured, and the control unit is used for monitoring and controlling the running state of the motor. The thrust measuring device provided by the utility model has the advantages of low cost, capability of realizing dynamic load direct connection and strong anti-interference performance, and meets the strict requirements of modern precision manufacturing on linear motor performance detection.

Description

Technical Field

[0001] This utility model belongs to the field of linear motor measurement technology, specifically relating to a device for measuring the rated thrust of a linear motor. Background Technology

[0002] A linear motor is a power device that converts electrical energy into mechanical energy for linear motion, and it is widely used in precision machining. The driving performance of a linear motor mainly depends on the output thrust it provides. In precision machining, if the output thrust of the linear motor is too small, the machined parts will have low precision; if the output thrust is too large, it will damage the parts. Therefore, measuring the thrust of a linear motor is particularly important.

[0003] Currently, the thrust of linear motors is mostly tested manually using gravity loading or by using a rotary motor with a ball screw.

[0004] The gravity loading method generates a reverse load by suspending standard weights on the moving parts of the motor. While this method can achieve static thrust calibration, it is limited by the lever ratio and the stacking height of the weights, making it difficult to balance the effective load range and accuracy, and the operation is cumbersome. In addition, the suspension vibration caused by the suspended weights can easily lead to oscillations in dynamic measurement data exceeding ±5%, and the motion inertia error caused by the loading mechanism cannot be eliminated.

[0005] The rotary motor-ball screw loading method uses a servo motor to drive a ball screw to generate counteracting thrust. Although this method can theoretically achieve dynamic loading, in practical applications, the backlash error of the screw pair (typically 0.05-0.1 mm) and elastic deformation can introduce periodic thrust fluctuations. Furthermore, this method has high requirements for equipment and is costly. Utility Model Content

[0006] To address the shortcomings of existing technologies, this invention provides a linear motor rated thrust measuring device. The purpose of this invention is to provide a low-cost thrust measuring device capable of direct dynamic load connection and strong anti-interference capabilities, thereby meeting the stringent requirements of modern precision manufacturing for linear motor performance testing.

[0007] The linear motor rated thrust measuring device provided by this utility model includes a test platform and a sliding plate that slides with the test platform; the linear motor under test is fixed on the test platform and drives the sliding plate to slide; a fixing block is also provided on the test platform, and a push rod that can be adjusted along the sliding direction of the sliding plate is threaded onto the fixing block; a force sensor is also provided on the sliding plate, the force sensor is located in the extension direction of the push rod, and the detection end of the force sensor is directly opposite the thrust end of the push rod; the linear motor rated thrust measuring device also includes a control unit that can be electrically connected to the linear motor under test, and the control unit is used to monitor and control the operating status of the motor.

[0008] As a further optimization of the linear motor rated thrust measuring device, at least two parallel guide rails are installed on the test platform, with a slider slidingly fitted on each guide rail, and a sliding plate installed on the top of the slider.

[0009] As a further optimization of the linear motor rated thrust measuring device, the stator of the linear motor under test is mounted on the test platform, and the mover of the linear motor under test is mounted on the bottom of the slide plate.

[0010] As a further optimization of the linear motor rated thrust measuring device, a pair of mounting blocks are set on the slide plate, and the force sensor is installed between the mounting blocks; the mounting block located at the force sensor detection end is floatingly connected to the slide plate; the mounting block located away from the force sensor detection end is fixedly connected to the slide plate.

[0011] As a further optimization of the linear motor rated thrust measuring device, the push rod is screwed into the threaded hole of the fixed block through a threaded fit; the end of the push rod away from the force sensor has a torque application part, and by rotating the torque application part, the push rod moves axially and forms a thrust resistance with the force sensor.

[0012] As a further optimization of the linear motor rated thrust measuring device, the control unit integrates a data acquisition element, which receives the thrust signal from the force sensor and the current signal from the linear motor under test in real time.

[0013] As a further optimization of the linear motor rated thrust measuring device, a coded ruler is set on the test platform along the extension direction of the guide rail, and a photoelectric sensor for detecting the coded ruler is set on the slider; the acquisition element receives the displacement signal relative to the coded ruler detected by the photoelectric sensor in real time.

[0014] As a further optimization of the linear motor rated thrust measuring device, the control unit also integrates a display element, which displays the current signal of the linear motor under test changing over time in real time.

[0015] As a further optimization of the linear motor rated thrust measuring device, the display element displays the following two curves aligned with the time axis in real time: the curve of the current signal of the linear motor under test changing with time, and the curve of the thrust signal of the force sensor changing with time.

[0016] As a further optimization of the linear motor rated thrust measuring device, the control unit is configured to trigger a stop command when the detected current signal exceeds 5% of the rated current value, and calculate the average value of the thrust value within the stable period corresponding to the stable period of the rated current value as the measured rated thrust.

[0017] Beneficial effects

[0018] This invention provides a low-cost, dynamic load-direct connection, and highly interference-resistant thrust measurement device that meets the stringent requirements of modern precision manufacturing for linear motor performance testing. Specifically, a rigid direct-connection sliding plate structure, dynamic load-resistance design, and automatic data processing enable high-precision dynamic measurement of the linear motor's rated thrust. Dual-rail support and floating mounting block leveling technology ensure no lateral deviation in the thrust transmission path; a precision trapezoidal thread pair with self-locking characteristics enables progressive and fine adjustment of the thrust resistance; a hyperbolic visualization interface intuitively presents the dynamic relationship between thrust and current; and combined with high-resolution encoder displacement closed-loop control, the rated thrust detection error rate is significantly reduced, while also simplifying the operation process. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of a device for measuring the rated thrust of a linear motor.

[0020] Figure 2 This is a side view of the device for measuring the rated thrust of a linear motor.

[0021] Figure 3 This is a top view of the device for measuring the rated thrust of a linear motor.

[0022] In the diagram, 1 is the test platform; 2 is the guide rail; 3 is the slider; 4 is the slide plate; 5 is the stator; 6 is the mover; 7 is the fixed block; 8 is the push rod; 9 is the mounting block; 10 is the force sensor; 11 is the encoder ruler; 12 is the photoelectric sensor; and 13 is the control unit. Detailed Implementation

[0023] The present invention is further illustrated by the following embodiments, which are intended to more clearly illustrate the technical solution of the present invention, and should not be construed as a limitation.

[0024] like Figure 1 , Figure 2 , Figure 3 The diagram illustrates a device for measuring the rated thrust of a linear motor. The main body of the device includes a horizontally positioned test platform 1, with a sliding plate 4 on its surface that can slide along a linear direction. The linear motor under test is fixedly mounted on the test platform 1, with its output end directly and rigidly connected to the sliding plate 4 to drive the plate 4 to slide along a preset sliding direction. A fixing block 7 is vertically welded to one end of the test platform 1, and a transversely through-hole is machined on the fixing block 7. A push rod 8 is screwed into this hole via a threaded fit, allowing for axial displacement adjustment along the sliding direction of the sliding plate 4 when the push rod 8 is rotated.

[0025] A force sensor 10 is fixedly mounted on the upper surface of the slide plate 4, with its detection end face facing the axial end of the push rod 8. When the slide plate 4 is driven to slide by the motor, the end of the push rod 8 is opposite to the detection end face of the force sensor 10. The control unit 13 is electrically connected to the linear motor via a cable, collects the current parameters of the motor in real time, and has motor start-stop control functions.

[0026] During thrust measurement, the linear motor is first activated to drive the slide plate 4 towards the push rod 8. The operator manually rotates the push rod 8, gradually pressing it against the force sensor 10 via threaded feed. At this point, the motor thrust and the opposing thrust applied by the push rod 8 create resistance at the force sensor 10. The control unit 13 continuously monitors the motor current. When the current value exceeds the rated current value, preferably 5%-30% above the rated current value, the motor power is cut off. The force data at the rated current value is extracted from the data recorded by the force sensor 10; this is the rated thrust value of the motor. This device allows the tester to finely control the loading process of the opposing thrust through the threaded adjustment of the push rod 8, ensuring accurate extraction of the rated thrust value of the linear motor.

[0027] Furthermore, two high-precision guide rails 2 are arranged parallel to each other along the length of the test platform 1. The guide rails 2 are fixed to the upper surface of the test platform 1 by countersunk bolts. The extension direction of the two guide rails 2 is parallel to the thrust axis of the linear motor, and the spacing between the guide rails 2 is symmetrically arranged according to the width of the slide plate 4. Each guide rail 2 is equipped with a linear slider 3, and the slider 3 integrates a ball bearing circulation structure to form a low-friction sliding pair with the guide rail 2. The slide plate 4 is made of rectangular steel plate, and its bottom is rigidly connected to the top of the two sliders 3 by bolts to form a stable double-rail support structure. This structure enables the slide plate 4 to maintain a linear motion trajectory along the thrust direction when subjected to the reverse load of the push rod 8, effectively suppressing lateral deviation.

[0028] Furthermore, the stator 5 of the linear motor under test is fixed to the test platform 1 with bolts, and the mover 6 is rigidly connected to the bottom of the slide plate 4 through a mounting bracket. When the linear motor is powered on, the electromagnetic force between the stator 5 and the mover 6 directly drives the slide plate 4 to slide along the guide rail 2. There is no intermediate transmission mechanism in the thrust transmission path, avoiding power loss. The top plane of the slide plate 4 simultaneously bears the reverse loads of the force sensor 10 and the push rod 8, forming a direct confrontation measurement system between the linear motor thrust and the manually applied resistance.

[0029] Furthermore, a pair of L-shaped mounting blocks 9 are bolted to the surface of the slide plate 4. The two mounting blocks 9 are positioned opposite each other along the sliding direction of the slide plate 4, forming a U-shaped clamping space. The bottom of the mounting block 9 near the push rod 8 is machined with an elongated hole, which forms a floating connection with the slide plate 4 through a pin, allowing the mounting block 9 to be finely adjusted by ±3mm along the thrust direction; the mounting block 9 on the other side is rigidly fixed to the slide plate 4 by countersunk bolts. The force sensor 10 is embedded in the slot between the two mounting blocks 9. When the push rod 8 applies a reverse thrust, the floating mounting block 9 can adaptively adjust its position to ensure that the detection end face of the force sensor 10 is precisely aligned with the axis of the push rod 8, eliminating the influence of lateral force caused by assembly errors on the measurement accuracy.

[0030] Furthermore, a trapezoidal thread is machined in the threaded hole of the fixing block 7, and a matching trapezoidal thread is machined on the corresponding position of the push rod 8, forming a precision thread pair. One end of the push rod 8 near the force sensor 10 is machined into a hemispherical end, and the surface is hardened to reduce the coefficient of friction; the other end extends into a hexagonal prism-shaped torque application part, the end face of which is engraved with a rotation direction mark. During operation, the torque application part can be turned directly by hand or an open wrench can be used to attach to the hexagonal prism. Rotating the push rod 8 clockwise will slowly push the hemispherical end towards the force sensor 10. When the slide plate 4 is driven by the motor to move, the progressive axial displacement of the push rod 8 forms a dynamic counter-load with the force sensor 10. The self-locking characteristic of the trapezoidal thread pair ensures that the push rod 8 does not retreat in the reverse direction during the force counter-load process, so that the force sensor 10 can continuously collect a stable counter-force signal.

[0031] Furthermore, the control unit 13 integrates a data acquisition card, whose analog input channels are connected to the output terminals of the force sensor 10 and the current feedback terminals of the linear motor driver via shielded cables. The data acquisition card synchronously acquires the thrust signal and the motor current signal at a sampling frequency of 1kHz. Before use, the force sensor 10 is calibrated at five points using standard weights to ensure a linear correspondence between the measured signal and the physical quantity.

[0032] Furthermore, an absolute magnetic grating encoder 11 is installed on the test platform 1 along the extension direction of the guide rail 2. The zero reference point of the encoder 11 is aligned with the initial position of the slide plate 4. The magnetic grating encoder 11 adopts a subdivision type with a resolution of 0.5μm. A photoelectric sensor 12 is fixedly installed on the bottom of the slider 3 via a bracket. This sensor includes a reading head and a signal processing module. The reading head maintains a detection gap of 0.3±0.05mm with the surface of the encoder 11. The photoelectric sensor 12 is connected to the data acquisition card of the control unit 13 through an interface, and uploads the displacement of the slide plate 4 in real time as the control basis for driving the linear motor. The control unit 13 compares the real-time displacement signal with the preset motion curve and dynamically adjusts the drive current of the linear motor to ensure that the slide plate 4 maintains a uniform speed of 0.1mm / s during the thrust resistance process.

[0033] Furthermore, the control unit 13's operation panel integrates a display element. On the display interface, the vertical axis represents the current range, and the sampling point interval is set to 100ms. The embedded processor uses the current signal acquired by the data acquisition card as the effective thrust current parameter, dynamically refreshing the display as a green curve for operator observation.

[0034] Preferably, the display element displays the following two time-axis aligned curves in real time: the current signal of the linear motor under test versus time, and the thrust signal of the force sensor 10 versus time. The display interface of the control unit 13 adopts a dual vertical axis design, with the left vertical axis indicating the current range and the right vertical axis indicating the thrust range, and the horizontal axis representing a unified time coordinate. The graphics processing module synchronously refreshes the green current signal curve and the blue thrust signal curve at 50ms intervals, with both curves sharing the same time reference source. The system stops when the current exceeds the rated value by 5%, calculates the average value of the thrust value within the stable period corresponding to the stable period of the rated current value as the measured rated thrust, and generates a report containing the two curves and their corresponding data.

[0035] The algorithm for calculating the rated thrust of the system specifically includes the following steps:

[0036] 1. Current steady segment identification: At the moment when the current exceeds the rated value by 5%, trace back the current curve data, calculate the standard deviation of the current value in each window by sliding time window with a window width of 0.5s and a step size of 0.1s, and select the longest continuous period with a standard deviation less than 2% of the rated current value and a duration of ≥1s as the current steady segment.

[0037] 2. Thrust Period Mapping: Based on the time axis alignment, extract the thrust curve time period that completely overlaps with the current steady period;

[0038] 3. Thrust steady zone extraction: During the mapped thrust time period, a double sliding window with a window width of 0.2s and a step size of 0.05s is used to calculate the thrust variance. Continuous sub-windows with variance < 5N² are selected as the effective steady zone.

[0039] 4. Mean Calculation: After removing the first and last 10% of the transitional data in the effective steady zone, the remaining thrust data are calculated using an arithmetic mean.

[0040] By employing a dual sliding window filtering mechanism, dynamic interference during motor startup and steady-state operating data are effectively separated, ensuring that the thrust measurement accurately reflects the continuous output capability under rated operating conditions. This allows users to visualize and monitor the dynamic relationship between thrust and current through simultaneous display of two curves and automatic data analysis. It also enables precise capture of the steady-state thrust value under rated operating conditions, significantly improving the accuracy and efficiency of measurement results.

[0041] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A device for measuring the rated thrust of a linear motor, characterized in that: The device includes a test platform (1) and a sliding plate (4) that slides with the test platform (1); the linear motor under test is fixed on the test platform (1) and drives the sliding plate (4) to slide; a fixing block (7) is also provided on the test platform (1), and a push rod (8) that can be adjusted along the sliding direction of the sliding plate (4) is threaded onto the fixing block (7); a force sensor (10) is also provided on the sliding plate (4), the force sensor (10) is located in the extension direction of the push rod (8), and the detection end of the force sensor (10) is directly opposite the thrust end of the push rod (8); the linear motor rated thrust measuring device also includes a control unit (13) that can be electrically connected to the linear motor under test, and the control unit (13) is used to monitor and control the operating status of the motor.

2. The linear motor rated thrust measuring device according to claim 1, characterized in that: The test platform (1) is equipped with at least two parallel guide rails (2), each guide rail (2) is slidably fitted with a slider (3), and the slide plate (4) is installed on the top of the slider (3).

3. The linear motor rated thrust measuring device according to claim 1, characterized in that: The stator (5) of the linear motor under test is mounted on the test platform (1), and the mover (6) of the linear motor under test is mounted on the bottom of the slide plate (4).

4. The linear motor rated thrust measuring device according to claim 1, characterized in that: A pair of mounting blocks (9) are provided on the slide plate (4), and the force sensor (10) is installed between the mounting blocks (9); the mounting block (9) located at the detection end of the force sensor (10) is floatingly connected to the slide plate (4); The mounting block (9), located away from the detection end of the force sensor (10), is fixedly connected to the slide plate (4).

5. The linear motor rated thrust measuring device according to claim 1, characterized in that: The push rod (8) is screwed into the threaded hole of the fixing block (7) through a threaded fit; the end of the push rod (8) away from the force sensor (10) has a torque application part, and by rotating the torque application part, the push rod (8) moves axially and forms a thrust resistance with the force sensor (10).

6. The linear motor rated thrust measuring device according to any one of claims 1 to 5, characterized in that: The control unit (13) integrates a data acquisition element, which receives the thrust signal from the force sensor (10) and the current signal from the linear motor under test in real time.

7. The linear motor rated thrust measuring device according to claim 6, characterized in that: The test platform (1) is equipped with a coding ruler (11) extending along the guide rail (2). The test platform (1) is equipped with at least two parallel guide rails (2), and each guide rail (2) is slidably fitted with a slider (3). The slider (3) is equipped with a photoelectric sensor (12) for detecting the encoder (11); the acquisition element receives the displacement signal relative to the encoder (11) detected by the photoelectric sensor (12) in real time.

8. The linear motor rated thrust measuring device according to claim 7, characterized in that: The control unit (13) also integrates a display element, which displays the curve of the current signal of the linear motor under test changing over time in real time.

9. The linear motor rated thrust measuring device according to claim 8, characterized in that: The display element displays the following two curves aligned with the time axis in real time: the current signal of the linear motor under test changes over time, and the thrust signal of the force sensor (10) changes over time.

10. The linear motor rated thrust measuring device according to claim 9, characterized in that: The control unit (13) is configured to trigger a stop command when the current signal is detected to exceed 5% of the rated current value, and to calculate the average value of the thrust value within the stable period corresponding to the stable period of the rated current value as the measured rated thrust.

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