Multi-point stress rod static balance system and use method thereof

Abstract

The invention relates to a multi-point stress rod static balance system and a using method thereof, and belongs to the technical field of workpiece static balance in the hydropower industry. The system comprises a workbench, a transmission device and a balancing device, four sets of stress rods are driven to move synchronously through a synchronous gear set, and the stress rods are adjustable in height and evenly distributed in the circumference. The method comprises coarse adjustment centering and fine adjustment centering, and the unbalanced weight is measured in combination with the resistance strain gauge. The limitation that a traditional single stress rod needs to be balanced after finish machining is broken through, the device is suitable for rough machining of workpieces and hollow parts, shaking caused by gravity center shifting is avoided through multi-point-position supporting, the data stabilization time is shortened, early balance detection and high-precision balance weight are achieved, and an efficient and reliable static balance solution is provided for heavy workpieces in the hydropower industry.

Description

Technical Field

[0001] The present invention relates to the technical field of static balancing of workpieces in the hydropower industry, and particularly to a multi-point stress rod static balancing system and a method for using the same. Background Art

[0002] In the hydropower industry, after the upper and lower blade discs of a runner or other annular and barrel-shaped parts are processed, static balancing treatment is required. By pasting counterweight blocks, the overall workpiece can be balanced. The static balancing treatment of the workpiece is a key link to ensure the stable operation of the equipment. At present, the relatively mature static balancing method in the industry is the single stress rod vertical static balancing. In this method, the stress rod is vertically placed at the geometric center of the workpiece, or the workpiece is connected to the stress rod through a tool connecting plate (as Figure 2 shown). However, this traditional balancing method has many defects:

[0003] First, the balancing can only be carried out after all the finishing machining of the workpiece. Since the tool connecting plate requires screw holes for use, and the rough-machined workpiece has not been machined with screw holes, the balancing detection cannot be carried out in advance. When it is found that the unbalanced weight of the workpiece is large after finishing machining, the treatment difficulty is extremely high, and there may even be a dilemma where there is no suitable position to place the counterweight block, seriously affecting the subsequent processing efficiency and quality.

[0004] Second, for hollow parts such as annular or barrel-shaped parts, if there is no position in the middle to set screw holes, the static balancing cannot be directly carried out. At this time, it can only be balanced together after being connected to other parts or tools. This will not only significantly increase the overall height of the workpiece, resulting in an increase in the center of gravity of the workpiece and an increase in safety risks, but also increase the manufacturing cost if custom-made special tools are required.

[0005] Third, in the traditional single stress rod balancing method, since the center of gravity of the workpiece may not fall within the support surface of the stress rod, the workpiece will shake for a long time, and it is necessary to wait for the reading to stabilize before reading the data, seriously affecting the work efficiency.

[0006] In view of the above problems, the present invention provides a four-point stress rod static balancing system. By using multiple horizontally placed stress rods, and the distribution diameter and height of the stress rods can be adjusted, the balancing can be carried out after the rough machining of the workpiece, and it is applicable to hollow parts where the tool connecting plate cannot be placed in the middle, effectively solving the deficiencies of the traditional method and providing diversified options for the balancing work. Summary of the Invention

[0007] The present invention aims to overcome the above-mentioned disadvantages of the prior art and provides a multi-point stress rod static balancing system and a method for using the same.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A multi-point stress rod static balancing system, comprising:

[0010] Workbench: The workbench is provided with multiple sliding grooves and synchronous gear mounting grooves. The multiple sliding grooves are arranged in a circumferential array and converge at the synchronous gear mounting groove.

[0011] Transmission device: It includes a motor and lead screws. The number of lead screws corresponds to the number of sliding grooves and is rotatably arranged in the multiple sliding grooves. The motor is arranged on the workbench to drive one of the lead screws to rotate. One end of multiple lead screws is provided with tapered synchronous gears. The multiple synchronous gears mesh with each other and form a synchronous gear set installed in the synchronous gear mounting groove. When the motor works, the multiple lead screws rotate synchronously.

[0012] Balancing device: It includes sliding seats, lifting devices, stress devices, and tightening devices corresponding to the number of sliding grooves. The bottom of the sliding seat is provided with nuts matching the lead screws. When the motor works, the sliding seat drives multiple balancing devices to move centripetally or centrifugally simultaneously. The lifting device is arranged at the upper end of the sliding seat to adjust the height of the balancing device. The stress device is arranged at the upper end of the lifting device to place the workpiece and measure its unbalance weight. The tightening device is arranged at the top of the balancing device to tightly hold the workpiece in multiple directions.

[0013] Furthermore, multiple synchronous gears form a gear set. The synchronous gear includes a driving gear and multiple driven gears. The motor drives the lead screw with the driving gear to rotate. When the driving gear rotates, it drives the multiple driven gears to rotate together, realizing the synchronous rotation of multiple lead screws.

[0014] Furthermore, the motor is a worm reduction motor. The gearbox of the worm reduction motor has a self-locking function to prevent the movement of the balancing device. The motor drives one of the lead screws to rotate through a chain.

[0015] Furthermore, the lifting device is a screw jack structure, including bevel gears, a lifting screw, and a lifting nut. When the bevel gear is rotated, it drives the lifting screw to rotate, converting the rotational motion into the linear motion of the lifting nut to realize the height adjustment of the stress device. The thread of the lifting screw has a self-locking function. The adjustment method of the lifting device includes manual operation and electric operation.

[0016] Furthermore, when the number of balancing devices is even, the stress device includes a stress bar and resistance strain gauges. The resistance strain gauges are pasted on the stress bar. A pair of opposite strain gauges are connected into a Wheatstone bridge. n strain gauges are connected into n / 2 Wheatstone bridges for connecting to a strain gauge to measure the unbalance weight of the workpiece.

[0017] Furthermore, the tightening device includes set screws and set screw seats. The set screws are installed on the set screw seats to form a screw pair for screw tightening. The set screws and the set screw seats are fixed on the stress device by screws, which can be conveniently replaced when the threads of the set screws or the set screw seats are damaged.

[0018] Further, the workbench is composed of a bottom plate, rib plates, and a panel. A number of screw holes are drilled on the panel for fastening tools such as square boxes, and a plurality of lifting holes are evenly distributed around the circumference of the panel for lifting and transferring.

[0019] Further, a method for using a multi-point stress bar static balance system includes the following steps:

[0020] S1: Check whether the height of the workpiece matches the height of the stress bar, and adjust the height of the stress bar through the lifting device as needed;

[0021] S2: Evenly distribute a plurality of square boxes and jacks on the upper plane of the workbench, and adjust the height so that the upper plane of the jack is slightly higher than the stress bar;

[0022] S3: Lift the workpiece to the center above the workbench and slowly lower it onto the jacks;

[0023] S4: Connect the strain gauge to electricity and set the data to zero;

[0024] S5: Measure the distance between the workpiece and the clamping device, and obtain data in multiple directions;

[0025] S6: According to the measurement data, use the clamping device to clamp the side with smaller data, so that the workpiece moves towards the side with larger data. When the data difference between the center point of the workpiece and the center point of the workbench is within a reasonable range, loosen the jacks to make the workpiece fall on the stress device;

[0026] S7: Observe the reading of the strain gauge to judge the orientation and magnitude of the unbalanced weight;

[0027] S8: Perform weight balancing treatment on the workpiece according to the judgment result.

[0028] Further, in step S6, the data difference between the center point of the workpiece and the center point of the workbench is within 0.10 mm.

[0029] Further, after step S6, continue to measure the offset of the center point of the workpiece with a micrometer, and adjust it through the clamping device until the data difference is within 0.02 mm.

[0030] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0031] The multi-point stress bar static balance system provided by the present invention has significant technical advantages:

[0032] Earlier applicable stage: Breaking through the limitation that the traditional single stress bar can only be balanced after the workpiece is finely processed, it can detect the unbalanced weight in advance in the rough machining stage (such as after the runner group welding), which is convenient for formulating a weight balancing plan in advance, reducing the difficulty of subsequent fine balancing, and helping to achieve the goal of "zero weight balancing".

[0033] Wider scope of application: The four-point horizontal stress rod design eliminates the need to reserve screw holes at the center of the workpiece, making it particularly suitable for hollow ring-shaped and barrel-shaped parts. It avoids the risk of increased center of gravity caused by combined balancing with other parts, and eliminates the need for customized special tools, reducing manufacturing costs.

[0034] Higher balance accuracy: The synchronous gear set and the lead screw pair are interlocked to ensure the synchronous movement of the four balancing devices. Combined with the fine adjustment of the tightening device and the self-locking lifting mechanism of the screw jack, the alignment accuracy of the workpiece center can be controlled within 0.02 mm. The four-point support keeps the center of gravity of the workpiece within the support surface, avoiding the shaking problem of traditional single-point balancing, shortening the stable time of the strain gauge reading, and improving the detection efficiency.

[0035] Stronger system stability: The self-locking function of the worm reduction motor prevents the device from displacing during tightening. The thread self-locking of the screw jack ensures the fixed height of the stress rod. With strong structural rigidity, it is suitable for heavy workpieces weighing 10 - 50 tons, providing safe and reliable diversified balancing solutions for the hydropower industry. Description of the Drawings

[0036] Figure 1 is the overall structural schematic diagram of the present invention;

[0037] Figure 2 is the solution used in the prior art;

[0038] Figure 3 is the structural schematic diagram during the balancing process of the impeller of the lower disc of the runner of the present invention;

[0039] Figure 4 is the structural schematic diagram of the workbench of the present invention;

[0040] Figure 5 is the internal structural schematic diagram of the workbench of the present invention;

[0041] Figure 6 is the partial sectional structural schematic diagram of the present invention.

[0042] Markings in the figure:

[0043] 1 - Workbench, 101 - Base plate, 102 - Rib plate, 103 - Panel, 2 - Transmission device, 201 - Motor, 202 - Lead screw, 203 - Synchronous gear, 204 - Synchronous gear set, 205 - Slide groove, 206 - Synchronous gear mounting groove, 3 - Balancing device, 301 - Slide seat, 302 - Nut, 303 - Bevel gear, 304 - Lifting screw, 305 - Lifting nut, 306 - Stress rod, 307 - Set screw, 308 - Set screw seat, 4 - Square box, 5 - Jack. Detailed Implementation Modes

[0044] The present invention will be described in detail below with reference to the drawings.

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] Embodiment 1

[0047] In this embodiment, as Figure 1 shown, a multi-point stress bar static balance system includes:

[0048] Workbench: The workbench is provided with a plurality of sliding grooves and synchronous gear mounting grooves. The plurality of sliding grooves are arranged in a circumferential array and converge at the synchronous gear mounting groove;

[0049] Transmission device: It includes a motor and a lead screw. The number of lead screws corresponds to the number of sliding grooves and is rotatably arranged in the plurality of sliding grooves. The motor is arranged on the workbench to drive one of the lead screws to rotate. One end of the plurality of lead screws is provided with a tapered synchronous gear, and the plurality of synchronous gears mesh with each other and form a synchronous gear group installed in the synchronous gear mounting groove. When the motor works, the plurality of lead screws rotate synchronously;

[0050] Balancing device: It includes sliding seats, lifting devices, stress devices and tightening devices corresponding to the number of sliding grooves. The bottom of the sliding seat is provided with a nut matching the lead screw. When the motor works, the sliding seat drives a plurality of balancing devices to perform centripetal or centrifugal movements simultaneously; The lifting device is arranged at the upper end of the sliding seat to adjust the height of the balancing device; The stress device is arranged at the upper end of the lifting device to place the workpiece and measure its unbalance weight; The tightening device is arranged at the top of the balancing device to tightly hold the workpiece in multiple directions.

[0051] The workbench is formed by welding a bottom plate, rib plates and a panel. 4 sliding grooves arranged in a circumferential array are opened on the panel, and the 4 sliding grooves converge at the synchronous gear mounting groove in the center. The sliding groove is of a T-shaped structure for accommodating the connecting plate at the bottom of the sliding seat. A synchronous gear group composed of four bevel gears is arranged in the synchronous gear mounting groove.

[0052] The motor of the transmission device is fixed to the bottom surface of the workbench through a bracket. The main shaft of the motor is connected to the driving sprocket and drives the driven sprocket through a chain. The driven sprocket is coaxially fixed with the lead screw. The 4 lead screws respectively correspond to the 4 sliding grooves. One end of the lead screw is machined with a bevel gear (synchronous gear), and the plurality of synchronous gears mesh. The lead screw nut is embedded in the bottom of the sliding seat to form a screw pair with the lead screw.

[0053] The sliding seat of the balancing device is fixed to the lead screw nut through screws. A lifting device with a screw jack structure is installed at the upper end of the sliding seat. A stress bar seat is fixed to the top of the lifting seat. The stress bar is fixed to the stress bar seat through screws. The setscrew and the setscrew seat are installed on the side of the stress bar seat through screws.

[0054] After the motor starts, one of the lead screws is driven to rotate through a sprocket and chain. The bevel gears of the lead screw drive the other three lead screws to rotate synchronously through the meshing between bevel gears. The lead screw nut drives the sliding seat to move centripetally or centrifugally along the chute, realizing the position adjustment of the balancing device; by rotating the bevel gear of the rotary lifting device, the lifting screw drives the lifting nut to move up and down to adjust the height of the stress bar.

[0055] The synchronous gear set ensures that the four lead screws rotate synchronously. Cooperating with the linear motion of the lead screw nuts, the four balancing devices move synchronously, ensuring that the workpiece support points are evenly distributed.

[0056] The chute guides the movement of the sliding seat. The lifting device adapts to workpieces of different heights. The tightening device adjusts the center of the workpiece. The stress device measures the unbalanced weight through strain gauges.

[0057] It solves the problems that traditional single stress bars need to be balanced after precision machining and hollow parts cannot be directly balanced, realizes the early balance detection of rough-machined workpieces, and reduces the difficulty of subsequent processing.

[0058] Furthermore, multiple synchronous gears form a gear set. The synchronous gears include a driving gear and multiple driven gears. The motor drives the lead screw with the driving gear to rotate. When the driving gear rotates, it drives the multiple driven gears to rotate together, realizing the synchronous rotation of multiple lead screws.

[0059] The synchronous gear set consists of 1 driving bevel gear and 3 driven bevel gears. The driving gear is coaxially fixed to the lead screw driven by the motor, and the 3 driven gears are respectively coaxially fixed to the other 3 lead screws. The tooth directions of the driving gear and the driven gears are opposite. The corresponding lead screws are divided into 2 right-handed lead screws and 2 left-handed lead screws, which are arranged at intervals on the circumference of the workbench.

[0060] When the driving gear rotates clockwise, the right-side driven gear rotates counterclockwise, driving the left-handed lead screw to rotate counterclockwise, and the corresponding lead screw nut moves inward; the left-side driven gear rotates clockwise, driving the right-handed lead screw to rotate clockwise, and the corresponding lead screw nut also moves inward, realizing the synchronous centripetal movement of the four balancing devices (the centrifugal movement principle is opposite).

[0061] Due to the orthogonal meshing characteristics of the bevel gears, the horizontal driving force of the motor is transmitted to the lead screws distributed in a circle. Through the lead screws with opposite helix directions, it ensures that the balancing devices move synchronously in the same direction.

[0062] Synchronization accuracy: The rigid connection of gear transmission ensures that the four lead screws rotate at the same speed, avoiding the unbalance of workpiece support caused by speed differences.

[0063] There is no need for a complex control system. High-precision synchronous motion is realized only through the mechanical structure, reducing costs and being easy to maintain.

[0064] Furthermore, the motor is a worm reduction motor, the gearbox of which has a self-locking function to prevent the balancing device from moving, and the motor drives one of the lead screws to rotate through a chain.

[0065] The motor uses a worm gear reduction motor, whose output shaft is a worm structure, meshing with the worm wheel (integrated in the sprocket). The worm and worm gear transmission inside the gearbox has a self-locking feature. When the motor is powered off, the worm wheel cannot reverse drive the worm, thereby locking the screw position.

[0066] When the jacking device jacks the workpiece, the reaction force of the workpiece on the jacking screw is transmitted to the screw nut through the balancing device, trying to push the screw to rotate. Due to the self-locking function of the worm gear motor, the screw is locked and the balancing device remains stationary, avoiding displacement affecting the accuracy of workpiece center adjustment.

[0067] The helix angle of the worm gear is smaller than the friction angle, forming a mechanical self-locking without the need for an additional brake device. It effectively resists the reaction force during tightening, ensures the workpiece is in a stable position during adjustment, and avoids measurement errors caused by device movement.

[0068] Improve system reliability, especially during high-precision alignment, to ensure that the balancing device remains in position and improve balancing efficiency.

[0069] Furthermore, the lifting device is a screw jack structure, including a bevel gear, a lifting screw and a lifting screw sleeve. When the bevel gear is rotated, the lifting screw is driven to rotate, converting the rotational motion into linear motion of the lifting screw sleeve, thereby realizing the height adjustment of the stress device; the thread of the lifting screw has a self-locking function; the adjustment methods of the lifting device include manual operation and electric operation.

[0070] The lifting device is a screw jack structure: a bevel gear is fixed on the upper end of the slide seat, meshing with the bevel gear on the lower end of the lifting screw. The lifting screw and the lifting screw sleeve form a trapezoidal thread pair, the outer side of the screw sleeve slides with the inner wall of the lifting seat, and the stress rod seat is fixed on the top of the lifting seat. The bevel gear is driven by a wrench during manual adjustment, and an electric torque wrench is used to connect the gear shaft during electric adjustment.

[0071] The rotating bevel gear drives the lifting screw to rotate through gear meshing. The lifting screw sleeve moves axially due to the thread transmission, pushing the lifting seat up and down to achieve the height adjustment of the stress rod. The self-locking characteristics of the thread pair ensure that the lifting seat is locked at any position.

[0072] The height of the stress rod can be adjusted to accommodate workpieces of different sizes (such as height differences of upper crown leaf disks) without the need for customized special tooling.

[0073] It takes into account both manual flexibility and electric efficiency, meets the needs of different scenarios, and expands the scope of application of the system.

[0074] Further, when the number of balancing devices is even, the stress device includes stress bars and resistance strain gauges. The resistance strain gauges are pasted on the stress bars. A pair of facing strain gauges are connected to form a Wheatstone bridge. n strain gauges are connected to form n / 2 Wheatstone bridges for connecting to a strain gauge to measure the unbalance weight of the workpiece.

[0075] The stress bar is a cylindrical metal rod, and resistance strain gauges are pasted directly below it. Each pair of facing strain gauges forms a Wheatstone bridge, and 4 strain gauges form 2 independent bridges. The strain gauges are connected to the strain gauge through wires, and the output voltage signal of the bridge reflects the bending moment borne by the stress bar.

[0076] When the workpiece is unbalanced, the offset of the center of gravity causes the stress bar to bear bending stress. The strain gauges generate resistance changes as the stress bar deforms, and the Wheatstone bridge outputs an unbalanced voltage. The voltage signal is collected by the strain gauge to calculate the orientation and magnitude of the unbalance weight of the workpiece.

[0077] Principle of bridge measurement: Utilize the piezoresistive effect of the strain gauge to convert mechanical stress into an electrical signal, and improve the measurement sensitivity and anti-interference ability through the Wheatstone bridge.

[0078] Redundant design: 2 bridges respectively monitor the stresses in two diametrical directions to ensure the uniform stress detection of multi-point supports for hollow parts (such as annular parts).

[0079] It is consistent with the traditional single stress bar measurement principle, but the four-point support avoids the shaking caused by the deviation of the center of gravity from the support surface, shortens the data stabilization time, and improves the efficiency.

[0080] Further, the tightening device includes a setscrew and a setscrew seat. The setscrew is installed on the setscrew seat to form a screw pair for screw tightening, and the setscrew and the setscrew seat are fixed on the stress device by screws, which can be conveniently replaced when the thread of the setscrew or the setscrew seat is damaged.

[0081] The tightening device includes a setscrew and a setscrew seat. The setscrew seat is fixed to the side of the stress bar seat by screws, and the setscrew forms a screw pair with the setscrew seat. The head of the setscrew is spherical, which can reduce the frictional resistance when contacting the workpiece, and a hexagonal wrench interface is provided at the tail of the setscrew.

[0082] Rotate the setscrew through a wrench, and the head of the setscrew pushes the side of the workpiece to adjust the position of the workpiece. When the thread of the setscrew or the setscrew seat wears, loosen the fixing screw to replace the whole, without disassembling the entire balancing device.

[0083] Through the linear feed of the setscrew, precisely control the micro-displacement of the workpiece, cooperate with a micrometer measurement (such as adjusting the difference of 0.10 mm) to align the center of the workpiece with the center of the workbench. The setscrew assembly is independently installed and can be quickly replaced when damaged, reducing the maintenance cost and improving the system reliability.

[0084] Solve the problem that traditional single stress rods rely on tool connection plates. By directly tightening the outer periphery of the workpiece with set screws, it is applicable to rough machining workpieces without screw holes or hollow parts.

[0085] Furthermore, the workbench consists of a bottom plate, rib plates and a panel. A number of screw holes are drilled on the panel for fastening tools such as square boxes, and multiple lifting holes are evenly distributed on the circumference of the panel for lifting and transferring.

[0086] The workbench panel is a rectangular steel plate, with cross-shaped rib plates welded to the bottom surface to enhance stiffness, and the bottom plate is fixed at the bottom. Four lifting holes are evenly distributed on the panel for hoisting by a crane; multiple groups of screw holes are opened at the edge of the panel for fixing auxiliary tools such as square boxes and jacks.

[0087] During hoisting, the steel wire rope passes through the lifting hole to fix the workbench; when installing the square box, the screw holes at the bottom of the square box are connected to the screw holes on the panel through bolts to support the workpiece for preliminary positioning.

[0088] Principle of structural strengthening: The rib plates improve the anti-deformation ability of the workbench to ensure rigid support of the workbench during the balancing process; the standardized design of the screw holes and lifting holes is compatible with general tools. The fixed function of the square box assists in pre-supporting the workpiece (such as the placement of the jack in step S2), and the lifting hole facilitates the overall handling of the system, improving the operation convenience.

[0089] Adapt to the balancing requirements of heavy workpieces, with stable structure and easy operation, reducing the customization cost of auxiliary tooling.

[0090] Embodiment 2

[0091] A method for using a multi-point stress rod static balancing system includes the following steps:

[0092] S1 Height matching: Observe the height of the bottom surface of the workpiece, and adjust the height of the stress rod through a lifting device (electric or manual) so that the top of the stress rod is slightly lower than the expected support surface of the workpiece by 5 mm.

[0093] S2 Pre-support setting: Place square boxes at four positions on the workbench panel, install jacks on the square boxes, and adjust the height of the jacks to be 5 mm higher than the top of the stress rod to form a temporary support.

[0094] S3 Workpiece positioning: The crane hoists the workpiece above the workbench and slowly lowers it onto the jacks, and initially aligns the center by visual inspection.

[0095] S4 Strain gauge zeroing: Connect the strain gauge wire to the strain gauge, power on and preheat, then zero it to eliminate the interference of the initial stress.

[0096] S5 Multi-directional measurement: Use an internal diameter micrometer to measure the distances between the outer periphery of the workpiece and the four setscrew seats, and record them as D1, D2, D3, D4 (corresponding to four directions).

[0097] S6 Coarse alignment: If D1 < D2 (opposite side data difference > 0.10 mm), rotate the setscrew in the D1 direction to push the workpiece towards the D2 direction until the opposite side data difference ≤ 0.10 mm. Then loosen the jack so that the gravity of the workpiece is transferred to the stress bar.

[0098] S7 Fine alignment: Measure the data again and fine-tune it through the setscrew until the opposite side data difference ≤ 0.02 mm to ensure high-precision alignment between the workpiece center and the workbench center.

[0099] S8 Unbalance detection: Observe the bridge voltage values displayed by the strain gauge and calculate the angle (such as the direction of the largest voltage difference) and weight (the torque corresponding to the voltage amplitude) of the unbalanced weight according to the preset algorithm.

[0100] S9 Counterweight treatment: Weld counterweight blocks or mill and reduce weight at the corresponding positions of the workpiece, and repeat the balance detection until the strain gauge reading approaches zero.

[0101] Principle of step-by-step alignment: Through two steps of coarse adjustment (0.10 mm) and fine adjustment (0.02 mm), combined with the spiral fine adjustment of the setscrew and the high-precision measurement of the micrometer, ensure that the center of gravity of the workpiece is located at the center of the balance system.

[0102] Data stability mechanism: The four-point support makes the center of gravity of the workpiece fall within the support surface, avoiding the shaking problem of the traditional single stress bar. The strain gauge reading quickly stabilizes, improving the detection efficiency.

[0103] Realize the early balance of rough-machined workpieces, determine the counterweight plan in advance, and lay a foundation for the final "zero counterweight" finish machining, especially suitable for the balance of tool-free connecting plates of hollow ring parts and barrel-shaped parts.

[0104] Furthermore, in step S6, the data difference between the workpiece center point and the workbench center point is within 0.10 mm.

[0105] When the measured opposite side data difference is 0.15 mm, rotate the setscrew in the D1 direction. Each time the setscrew is rotated 1 circle (pitch 1 mm), the setscrew advances 1 mm. Monitor it in real time through the micrometer until the difference ≤ 0.10 mm. After loosening the jack, the gravity of the workpiece is supported by the stress bar. At this time, the setscrew still keeps in contact but does not apply thrust to avoid affecting the stress measurement.

[0106] Precision quantization control: 0.10 mm is used as the coarse adjustment threshold to ensure that the workpiece is initially stabilized on the stress bar and avoid excessive offset of the workpiece caused by over-adjustment.

[0107] Gravity transfer safety: The jack pre-supports to bear most of the weight of the workpiece, and the setscrew is only used for fine adjustment to prevent the stress bar from being overloaded and protect the measuring device.

[0108] Further, after step S6, continue to measure the offset of the workpiece center point with a micrometer and adjust it through the tightening device until the data difference is within 0.02 mm.

[0109] After rough adjustment, measure again. If the data difference on the opposite side is 0.05 mm, use a micrometer with an accuracy of 0.01 mm to finely adjust the jackscrew successively, rotating 1 / 10 of a turn (0.1 mm feed) each time until the difference ≤ 0.02 mm. At this time, the center offset of the workpiece is controlled at the micron level, meeting the high-precision balance requirement.

[0110] Through rough adjustment for quick positioning and fine adjustment to eliminate small deviations, utilize the screw drive accuracy of the jackscrew (0.1 mm / turn) to match the measurement accuracy of the micrometer, achieving error control from the millimeter level to the micron level.

[0111] High-precision centering ensures uniform stress on the stress rod. The strain gauge signal only reflects the unbalanced weight of the workpiece, excluding the interference caused by center offset and improving the accuracy of the measurement result.

[0112] The above are only the preferred embodiments of the invention and are not intended to limit the invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A multi-point stress bar static balance system, characterized in that: Including: Workbench: The workbench is provided with a plurality of sliding grooves and synchronous gear mounting grooves. The plurality of sliding grooves are arranged in a circumferential array and converge at the synchronous gear mounting groove. Transmission device: It includes a motor and a lead screw. The number of lead screws corresponds to the number of sliding grooves and is rotatably arranged in the plurality of sliding grooves. The motor is arranged on the workbench to drive one of the lead screws to rotate. One end of the plurality of lead screws is provided with a tapered synchronous gear. The plurality of synchronous gears mesh with each other and form a synchronous gear set installed in the synchronous gear mounting groove. When the motor works, the plurality of lead screws rotate synchronously. Balancing device: It includes sliding seats, lifting devices, stress devices and clamping devices corresponding to the number of sliding grooves. The bottom of the sliding seat is provided with a nut matching the lead screw. When the motor works, the sliding seat drives a plurality of balancing devices to perform centripetal or centrifugal movements simultaneously. The lifting device is arranged at the upper end of the sliding seat to adjust the height of the balancing device. The stress device is arranged at the upper end of the lifting device to place the workpiece and measure its unbalance weight. The clamping device is arranged at the top of the balancing device to clamp the workpiece in multiple directions.

2. The multi-point stress rod static balance system according to claim 1, wherein: The plurality of synchronous gears form a gear set. The synchronous gear includes a driving gear and a plurality of driven gears. The motor drives the lead screw with the driving gear to rotate. When the driving gear rotates, it drives the plurality of driven gears to rotate together, realizing the synchronous rotation of the plurality of lead screws.

3. A multi-point stress bar static balance system according to claim 1, characterized in that: The motor selects a worm reduction motor. The gearbox of this worm reduction motor has a self-locking function to prevent the balancing device from moving. The motor drives one of the lead screws to rotate through a chain.

4. A multi-point stress bar static balance system according to claim 1, characterized in that: The lifting device is of a screw jack structure, including bevel gears, a lifting screw and a lifting nut. When the bevel gear is rotated, it drives the lifting screw to rotate, converting the rotational motion into the linear motion of the lifting nut to realize the height adjustment of the stress device. The thread of the lifting screw has a self-locking function. The adjustment method of the lifting device includes manual operation and electric operation.

5. A multi-point stress bar static balance system according to claim 1, characterized in that: When the number of balancing devices is even, the stress device includes a stress bar and resistance strain gauges. The resistance strain gauges are pasted on the stress bar. A pair of opposite strain gauges are connected into a Wheatstone bridge. n strain gauges are connected into n / 2 Wheatstone bridges for connecting to a strain gauge to measure the unbalance weight of the workpiece.

6. The multi-point stress bar static balance system according to claim 1, wherein: The clamping device includes set screws and set screw seats. The set screws are installed on the set screw seats to form a screw pair for screw fastening. The set screws and the set screw seats are fixed on the stress device through screws, which can be conveniently replaced when the threads of the set screws or the set screw seats are damaged.

7. A multi-point stress rod static balance system according to claim 1, characterized in that: The workbench is composed of a bottom plate, rib plates and a panel. A number of screw holes are drilled on the panel for fastening tools such as square boxes, and a plurality of lifting holes are evenly distributed on the circumference of the panel for lifting and transferring.

8. A method for using a multi-point stress bar static balance system, which is applied to the multi-point stress bar static balance system described in any one of claims 1-7, and is characterized in that: Including the following steps: S1: Check whether the height of the workpiece matches the height of the stress bar, and adjust the height of the stress bar through the lifting device as needed. S2: Evenly distribute a plurality of square boxes and jacks on the upper plane of the workbench, and adjust the height so that the upper plane of the jacks is slightly higher than the stress bar. S3: Lift the workpiece to the center above the workbench and slowly place it on the jacks. S4: Connect the power supply to the strain gauge and set the data to zero. S5: Measure the distance between the workpiece and the clamping device to obtain data in multiple directions. S6: According to the measurement data, the side with smaller data is tightened by the clamping device, so that the workpiece moves towards the side with larger data. When the data difference between the center point of the workpiece and the center point of the workbench is within a reasonable range, the Panasonic jack makes the workpiece fall on the stress device; S7: Observe the readings of the strain gauge to judge the orientation and magnitude of the unbalanced weight; S8: Carry out weight balancing treatment on the workpiece according to the judgment result.

9. The method of using a multi-point stress rod static balance system according to claim 8, characterized in that: In the step S6, the data difference between the center point of the workpiece and the center point of the workbench is within 0.10 mm.

10. The method of using a multi-point stress rod static balance system according to claim 8, characterized in that: After the step S6, continue to measure the offset of the center point of the workpiece with a micrometer and adjust it through the clamping device until the data difference is within 0.02 mm.

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