WO2021244426A1 - 平衡下落机构和重力仪 - Google Patents

平衡下落机构和重力仪 Download PDF

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Publication number
WO2021244426A1
WO2021244426A1 PCT/CN2021/096792 CN2021096792W WO2021244426A1 WO 2021244426 A1 WO2021244426 A1 WO 2021244426A1 CN 2021096792 W CN2021096792 W CN 2021096792W WO 2021244426 A1 WO2021244426 A1 WO 2021244426A1
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WIPO (PCT)
Prior art keywords
balancer
pulley
mass
steel belt
rotating mechanism
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PCT/CN2021/096792
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English (en)
French (fr)
Inventor
伍康
文艺
郭梅影
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清华大学
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Application filed by 清华大学 filed Critical 清华大学
Publication of WO2021244426A1 publication Critical patent/WO2021244426A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V7/00—Measuring gravitational fields or waves; Gravimetric prospecting or detecting
    • G01V7/14—Measuring gravitational fields or waves; Gravimetric prospecting or detecting using free-fall time
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V7/00—Measuring gravitational fields or waves; Gravimetric prospecting or detecting
    • G01V7/02—Details

Definitions

  • This application relates to the technical field of precision instruments, in particular to a balanced falling mechanism and a gravimeter.
  • the classic free-fall absolute gravimeter adopts frequency-stabilized laser interferometry technology, which is used to accurately measure the displacement and time of the mass in the free-fall motion in a vacuum environment, and finally fit the free-fall motion parameters To get the absolute gravitational acceleration. Therefore, the precise measurement of the displacement of a free-falling body is the key to obtain the high-precision absolute gravitational acceleration value.
  • the measurement process during the free fall movement is often interfered by the vibration and noise from the instrument itself and the instrument support, and the interference of the vibration and noise will affect the accuracy of the absolute gravity measurement.
  • the recoil vibration of the instrument itself caused by the gravimeter transmission mechanism in the process of realizing the free fall motion of the test mass is the most influential vibration disturbance, which will introduce system deviations in the gravity measurement.
  • a balance falling mechanism including:
  • a housing which surrounds and forms a containing cavity, the containing cavity having a vertical central axis of symmetry;
  • the first rotating mechanism and the second rotating mechanism are arranged in the accommodating cavity, and are arranged symmetrically about the central symmetry axis on both sides of the central symmetry axis;
  • the first balancer and the second balancer are arranged in the accommodating cavity, are respectively connected to the first rotation mechanism and the second rotation mechanism, and are symmetrically arranged on both sides of the central symmetry axis;
  • a carrier for placing the mass to be tested is arranged on the central symmetry axis, and is drivingly connected to the first rotating mechanism and the second rotating mechanism;
  • the first rotating mechanism and the second rotating mechanism are used to drive the carrier and the first balancer and the second balancer to move in opposite directions in a vertical direction at the same speed;
  • the driving device is arranged in the housing;
  • the adjusting member is in transmission connection with the driving device, and the driving device is used to drive the adjusting member to move in the vertical direction, so that the mass to be tested makes the free fall movement in the accommodating cavity
  • the overall center of mass of the gravimeter remains unchanged.
  • the driving device includes:
  • the cam is vertically rotatably arranged on the top of the casing;
  • the sliding rail is arranged vertically on the top of the housing, the adjusting member is slidably arranged on the sliding rail and abuts against the cam, and when the cam rotates, the adjusting member is driven along the sliding rail Move in the vertical direction.
  • the cam determines that the adjusting member is in the vertical position according to the mass of the mass to be measured, the mass of the adjusting member, the displacement of the bearing member, and the displacement of the mass to be measured. The displacement of the direction.
  • the driving device includes a base and a supporting plate, which are arranged at intervals along the vertical direction on the top of the housing, and the sliding rail is arranged between the base and the supporting plate.
  • the supporting plate is provided with an opening for passing the adjusting member.
  • the driving device further includes a support seat, which is arranged on the base, and the cam is rotatably arranged on the support seat.
  • the driving device includes a screw rod, the screw rod is vertically rotatably arranged on the top of the housing, the adjusting member is a nut, and the nut is threadedly engaged with the screw rod. When the screw rod rotates, the nut is driven to move in the vertical direction.
  • it further includes two single-sided racks and one double-sided rack, the first rotating mechanism and the second rotating mechanism are both gears, and the first balancer and the second balancer are respectively One of the single-sided racks is connected to one of the gears, and the carrier is connected to two of the gears through the double-sided racks.
  • the first rotation mechanism includes:
  • the first pulley and the second pulley arranged along the vertical direction;
  • a first steel belt and a second steel belt the two ends of the first steel belt are respectively connected to the first balancer and the bearing member, and the two ends of the second steel belt are respectively connected to the first balancer Connected to the carrier, and the first steel belt, the second steel belt, the first balancer and the carrier constitute a closed loop surrounding the first pulley and the second pulley;
  • the second rotating mechanism includes:
  • the third pulley and the fourth pulley arranged along the vertical direction;
  • a third steel belt and a fourth steel belt both ends of the third steel belt are respectively connected to the second balancer and the bearing member, and both ends of the fourth steel belt are respectively connected to the second balancer
  • the third steel belt, the fourth steel belt, the second balancer and the bearing member form a closed loop surrounding the third pulley and the fourth pulley.
  • it further includes a servo motor, which is in driving connection with one of the first pulley, the second pulley, the third pulley, or the fourth pulley.
  • a gravimeter includes the balance falling mechanism.
  • the driving device can drive the adjusting member to move in a vertical direction.
  • the bearing and the mass to be measured move in the vertical direction, and the mass to be measured is separated from the bearing so that the mass to be measured makes a free fall motion
  • the momentum theorem of the mass point system can be passed
  • the whole balance falling mechanism is analyzed, and the overall center of mass of the balance falling mechanism remains unchanged as the control target, and the state of the adjustment member moving in the vertical direction is obtained.
  • the overall center of mass of the balance falling mechanism can be kept unchanged, thereby eliminating the influence of the recoil vibration on the absolute gravity measurement process and improving the measurement accuracy.
  • Figure 1 is a schematic diagram of a balanced falling mechanism provided by an embodiment of the application.
  • FIG. 2 is a three-dimensional schematic diagram of a driving device provided by an embodiment of the application.
  • Fig. 3 is a front view of a driving device provided by an embodiment of the application.
  • Figure 4 is a front view of a cam structure provided by an embodiment of the application.
  • Figure 5 is a sectional view of a cam structure provided by an embodiment of the application.
  • FIG. 6 is a schematic diagram of a screw screw structure provided by another embodiment of the application.
  • Fig. 7 is a schematic diagram of a rack and pinion structure provided by another embodiment of the application.
  • the first rotating mechanism 210 The first rotating mechanism 210
  • the first balancer 310 The first balancer 310
  • first and second are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality of” means at least two, such as two, three, etc., unless specifically defined otherwise.
  • the terms “installed”, “connected”, “connected”, “fixed” and other terms should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection , Or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components, unless otherwise specified The limit.
  • installed can be a fixed connection or a detachable connection , Or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components, unless otherwise specified The limit.
  • the first feature “on” or “under” the second feature may be in direct contact with the first and second features, or the first and second features may be indirectly through an intermediary. get in touch with.
  • the "above”, “above” and “above” of the first feature on the second feature may mean that the first feature is directly above or obliquely above the second feature, or it simply means that the level of the first feature is higher than that of the second feature.
  • the first feature "below”, “below” and “below” the second feature can mean that the first feature is directly below or obliquely below the second feature, or it simply means that the level of the first feature is smaller than the second feature.
  • the balance falling mechanism 10 includes a housing 100, a first rotation mechanism 210, a second rotation mechanism 220, a first balancer 310, a second balancer 320, a carrier 330, a driving device 400 and an adjustment member 430.
  • the housing 100 surrounds and forms a receiving cavity 110.
  • the accommodating cavity 110 has a vertical central axis of symmetry 120.
  • the first rotating mechanism 210 and the second rotating mechanism 220 are disposed in the containing cavity 110.
  • the first rotation mechanism 210 and the second rotation mechanism 220 are symmetrically arranged on both sides of the central symmetry axis 120 with respect to the central symmetry axis 120.
  • the first balancer 310 and the second balancer 320 are accommodated in the containing cavity 110.
  • the first balancer 310 and the second balancer 320 are drivingly connected to the first rotating mechanism 210 and the second rotating mechanism 220, respectively.
  • the first balancer 310 and the second balancer 320 are symmetrically arranged on both sides of the central axis of symmetry 120.
  • the supporting member 330 is used to place the mass member 340 to be tested.
  • the carrier 330 is disposed on the central symmetry axis 120.
  • the carrier 330 is drivingly connected to the first rotating mechanism 210 and the second rotating mechanism 220.
  • the first rotating mechanism 210 and the second rotating mechanism 220 can drive the carrier 330 and the first balancer 310 and the second balancer 320 to move in opposite directions in the vertical direction at the same speed. sports.
  • the driving device 400 is arranged on the top of the housing 100.
  • the adjusting member 430 is drivingly connected with the driving device 400.
  • the driving device 400 can drive the adjusting member 430 to move in the vertical direction, so that the mass center of the balance falling mechanism 10 remains unchanged when the mass to be measured 340 is freely falling in the containing cavity 110 .
  • the housing 100 may have a cubic structure.
  • the accommodating cavity 110 may be vacuum. In a vacuum environment, reducing the air resistance generated when the object falls is small.
  • the first rotating mechanism 210 and the second rotating mechanism 220 may be arranged on the same horizontal line.
  • the first rotating mechanism 210 and the second rotating mechanism 220 can drive the first balancer 310, the second balancer 320, and the carrier 330 to move up or down in a vertical direction through rotation.
  • the first rotating mechanism 210 and the second rotating mechanism 220 may be counterweights with a certain mass.
  • the first rotating mechanism 210 and the second rotating mechanism 220 may both have a circular structure. The diameters of the circular structures may be the same.
  • the supporting member 330 may be linked with the first balance member 310 and the second balance member 320 through the first rotation mechanism 210 and the second rotation mechanism 220. It can be understood that when the first rotating mechanism 210 on the left rotates counterclockwise and the second rotating structure 220 on the right rotates clockwise at the same speed, the carrier 330 rises in the vertical direction, and the first The balance piece 310 and the second balance piece 320 descend at the same speed in the vertical direction. When the first rotating mechanism 210 rotates clockwise and the second rotating structure 220 rotates counterclockwise at the same speed, the first rotating mechanism 210 and the second rotating mechanism 220 can drive the first balancer 310 It rises synchronously with the second balancer 320 in the vertical direction.
  • the carrier 330 descends at the same speed in the vertical direction.
  • the mass to be tested 340 placed on the supporting member 330 is separated therefrom and performs a free fall motion.
  • the local gravitational acceleration can be calculated by measuring the displacement time pair of the falling trajectory of the mass 340 to be tested.
  • the sum of the masses of the first balancer 310 and the second balancer 320 may be equal to the sum of the carrier 330 and the mass to be tested 340 placed on the carrier 330.
  • the supporting member 330 may be caused to drive the mass member 340 to be measured to rise.
  • the supporting member 330 can be controlled to accelerate downward with an acceleration greater than g, so that the supporting member 330 and the mass to be tested 340 are separated. At this time, the mass to be tested 340 starts to make a free fall motion.
  • the separation distance between the supporting member 330 and the mass to be tested 340 can be controlled to be kept within a set range.
  • the distance between the bearing member 330 and the mass member 340 to be tested is kept within 10 mm, so that it can reduce the occurrence of large amounts when the mass member to be tested 340 falls on the bearing member 330.
  • the impact force is reduced, thereby reducing the damage to the mass to be tested 340 and the carrier 330, and increasing the number of times the parts can be repeatedly used for measurement. It can also ensure the accuracy of the position where the mass part 340 to be tested falls on the carrier 330, and ensure the repeatability of each drop measurement.
  • the linkage distance between the supporting member 330, the first balance member 310, and the second balance member 320 can be controlled, and thus the distance at which the mass member 340 can be freely fallen can be controlled.
  • the free fall distance of the test mass 340 is greater than 20 cm. Within this range, the displacement time data obtained by measuring the mass 340 to be measured is more, and the accuracy of the gravitational acceleration value obtained by fitting is higher, which can reach an accuracy of the order of ⁇ Gal (10-8m/s2).
  • the carrier 330 can be slowed down and then lightly received the mass to be tested 340, and then the mass to be tested 340 is brought back to the ascending initial position.
  • the driving device 400 can drive the adjusting member 430 to move in a vertical direction.
  • the supporting member 330 and the mass to be measured 340 move in the vertical direction, and the mass to be measured 340 is separated from the supporting member 330 so that the mass to be measured 340 makes a free fall motion
  • the overall balance falling mechanism 10 is analyzed by the mass point momentum theorem, and the overall center of mass of the balance falling mechanism 10 remains unchanged as the control objective, and the state of the adjusting member 430 moving in the vertical direction is obtained.
  • the movement state of the adjusting member 430 can be controlled to keep the overall center of mass of the balance falling mechanism 10 unchanged, thereby eliminating the influence of the recoil vibration on the measurement process.
  • the supporting member 330 when the supporting member 330 carries the mass to be measured 340 ascending, the supporting member 330 and the mass to be measured 340 move upward as a whole, and the first balancer 310 and The second balancer 320 moves downwards at an equal and reverse speed.
  • the momentum theorem of the mass point system
  • F N is the supporting force received by the balance falling mechanism 10, m 1 , m 2 , m 3 , and m 4 respectively represent the mass to be tested 340, the bearing member 330, and the first balance member 310 and The mass of the second balancer 320, ⁇ p represents the momentum change of the system in any integral time period, ⁇ v 1 , ⁇ v 2 , ⁇ v 3 , and ⁇ v 4 respectively represent the mass to be tested 340, the bearing 330 and the The speed changes of the first balancer 310 and the second balancer 320 in any integral time period are described.
  • G all is the gravity received by the mass to be measured 340, the bearing member 330, the first balance member 310 and the second balance member 320.
  • a 1 (t) and a 2 (t) are the accelerations of the mass part 340 and the bearing part 330 during the falling process, respectively.
  • Equation (8) integrates both sides of the equal sign at the same time to obtain:
  • the movement displacement of the adjusting member 430 during the falling process is related to the separation distance s 2 (t)-s 1 (t) of the mass member 340 to be tested and the bearing member 330.
  • the rotation speeds of the first rotating mechanism 210 and the second rotating mechanism 220 can be controlled by a servo motor.
  • the balance falling mechanism 10 can be applied to a gravimeter.
  • the gravimeter may be an absolute gravimeter.
  • the absolute gravimeter can obtain the displacement time pair of the free fall trajectory of the mass 340 to be measured during the fall process through an interferometric device.
  • the principle of displacement interferometry is similar to that of the Michelson interferometer, and the interferometric device may include a laser, a corner cube, a beam splitter, and a photodetector.
  • the light beam emitted by the laser is divided into a measuring light and a reference light by a beam splitter, wherein the measuring light propagates upward through the corner cube and the reference corner cube fixed inside the mass to be measured 340.
  • the interference fringe signal containing the drop displacement information is acquired by the photodetector. Therefore, theoretically, the falling displacement obtained by the interferometric measurement is the movement displacement of the mass to be measured 340 relative to the reference prism. Therefore, the movement displacement s 1 (t) of the mass to be measured 340 can also be obtained from the falling interference fringes. Therefore, the movement displacement of the adjusting member 430 can be obtained.
  • the displacement of the adjusting member 430 By controlling the displacement of the adjusting member 430 to satisfy the formula (10), the effect of keeping the overall center of mass of the balanced falling mechanism 10 unchanged can be achieved.
  • balance falling mechanism 10 can also be applied to other mechanisms that need to balance recoil vibration.
  • the driving device 400 includes a cam 410 and a sliding rail 420.
  • the cam 410 is vertically rotatably arranged on the top of the housing 100.
  • the sliding rail 420 is vertically arranged on the top of the housing 100.
  • the adjusting member 430 is slidably disposed on the sliding rail 420. And abut the cam 410.
  • the cam 410 rotates, the adjusting member 430 is driven to move in the vertical direction along the sliding rail 420.
  • the contour of the cam 410 can determine the displacement of the adjusting member 430.
  • the profile and diameter of the cam 410 can be set by the displacement of the adjusting member 430, so as to ensure that the displacement of the adjusting member 430 meets the formula (10) when the cam 410 rotates.
  • the cam 410 may be driven to rotate by a servo motor.
  • the servo motor has good control accuracy.
  • the cam 410 can be driven to rotate at a uniform speed by the servo motor, and the profile and diameter of the cam 410 can be set to ensure that the displacement of the adjusting member 430 satisfies the formula (10).
  • the driving device 400 includes a base 450 and a supporting plate 440.
  • the base 450 and the supporting plate 440 may be arranged on the top of the housing 100 at intervals along the vertical direction.
  • the sliding rail 420 is disposed between the base 450 and the supporting plate 440.
  • the base 450 and the supporting plate 440 may both have a disc structure.
  • the base 450 and the supporting plate 440 may be arranged in parallel.
  • the sliding rail 420 includes two sliding rods 421, and the two sliding rods 421 are arranged between the base 450 and the supporting plate 440 at intervals.
  • Two ends of the adjusting member 430 are slidably disposed on one of the sliding rods 421 respectively.
  • the cam 410 may also be arranged between the two sliding rods 421. When the cam 410 rotates, the adjusting member 430 can be driven to move in the vertical direction along the two sliding rods 421.
  • linear bearings 431 may be installed at both ends of the adjusting member 430.
  • the linear bearings 431 may be sleeved on the outside of the one sliding rod 421 respectively.
  • the supporting plate 440 is provided with an opening 442. Used to pass the adjusting member 430.
  • the shape of the opening 442 may be square or round.
  • the driving device 400 further includes a supporting seat 460.
  • the supporting base 460 is disposed on the base 450, and the cam 410 is rotatably disposed on the supporting base 460.
  • the driving device 400 includes a screw rod 470.
  • the screw rod 470 is vertically rotatably arranged on the top of the housing 100.
  • the adjusting member 430 is a nut.
  • the nut is threadedly engaged with the screw rod 470.
  • the screw rod 470 rotates, the nut is driven to move in the vertical direction.
  • the screw 470 can be controlled by a servo motor.
  • the rotation speed of the screw rod 470 can be controlled, and the displacement of the nut in the vertical direction can be controlled.
  • the rotation speed of the screw rod 470 can be controlled, so that the displacement of the adjusting member 430 meets the above requirements.
  • a mounting unit 480 may be provided at both ends of the screw rod 470, and the servo motor may drive the screw rod 470 to rotate through a mounting unit.
  • the balance falling mechanism 10 further includes two single-sided racks 510 and one double-sided rack 520.
  • the first rotation mechanism 210 and the second rotation mechanism 220 are both gears.
  • the first balancer 310 and the second balancer 320 are respectively connected to one of the gears via a single-sided rack 510.
  • the carrier 330 is connected to the two gears in transmission via the double-sided rack 520. It can be understood that the double-sided rack 520 may be arranged on the central symmetry axis 120.
  • the first balancer 310 and the second balancer 320 may be respectively arranged at one end of the single-sided rack 510.
  • the supporting member 330 is disposed at one end of the double-sided rack 520.
  • the double-sided rack 520 is located between the two gears, and two sides of the double-sided rack 520 mesh with the two gears respectively.
  • the double-sided rack 520 carries the carrier 330 down.
  • the two single-sided racks 510 respectively carry the first balance member 310 and the second balance member 320 ascending.
  • the movement of the supporting member 330 can be controlled to realize the rising and falling process of the mass to be tested 340. Since the lengths of the single-sided rack 510 and the double-sided rack 520 can be set as required, the long-distance free fall movement of the mass to be measured 340 during the falling process can be ensured, thereby improving the accuracy of measurement .
  • the first rotating mechanism 210 includes a first pulley 212 and a second pulley 214, a first steel belt 216 and a second steel belt 218 arranged along a vertical direction.
  • the two ends of the first steel strip 216 are respectively connected to the first balancer 310 and the carrier 330.
  • the first steel belt 216 may be arranged around the upper semicircle of the first pulley 212.
  • the two ends of the first steel belt 216 can hang down symmetrically from the two ends of the first pulley 212 and connect the first balancer 310 and the carrier 330 respectively.
  • the second steel belt 218 may be arranged around the lower semicircle of the second pulley 214. Both ends of the second steel belt 218 may be connected to the first balancer 310 and the carrier 330 respectively. Therefore, the first steel belt 216, the second steel belt 218, the first balancer 310 and the carrier 330 constitute a closed loop surrounding the first pulley 212 and the second pulley 214, and pass The first pulley 212 and the second pulley 214 form the first steel belt 216, the second steel belt 218, the first balancer 310 and the carrier 330 into a tight closed loop structure.
  • the second rotating mechanism 220 includes a third pulley 222 and a fourth pulley 224, a third steel belt 226 and a fourth steel belt 228 arranged along the vertical direction. Two ends of the third steel strip 226 are respectively connected to the second balancer 320 and the supporting member 330. The third steel belt 226 can go around the upper semicircle of the third pulley 222. Both ends of the third steel strip 226 extend downward and are connected to the second balancer 320 and the supporting member 330 respectively.
  • Both ends of the fourth steel belt 228 bypass the fourth pulley 224 and extend upward, and are connected to the second balancer 320 and the carrier 330 respectively.
  • the fourth pulley 224 and the third pulley 222 tension the fourth steel belt 228 and the third steel belt 226. Therefore, the fourth steel belt 228, the second balance member 320 and the bearing member 330 constitute a tight closed loop structure surrounding the third pulley 222 and the fourth pulley 224.
  • the balance falling mechanism 10 further includes a servo motor.
  • the servo motor In the servo motor, one of the first pulley 212, the second pulley 214, the third pulley 222, or the fourth pulley 224 is drivingly connected. That is, as long as the first pulley 212, the second pulley 214, the third pulley 222, or the fourth pulley 224 has one rotation, the first steel belt 216, the second steel belt 218, Driven by the third steel belt 226 or the fourth steel belt 228, other remaining pulleys will rotate accordingly. Therefore, the carrier 330 can be controlled to move upward or downward.
  • the servo motor is drivingly connected to the fourth pulley 224.
  • the carrier 330 drives the first steel belt 216 and the second steel belt 218 to rotate.
  • the rotation of the first steel belt 216 and the second steel belt 218 can drive the first pulley 212 and the second pulley 214 to rotate.
  • the ascent of the carrier 330 can be increased. Or the distance of descent. Therefore, the free fall distance of the mass part 340 to be tested can be increased, the amount of data collection can be increased, and the measurement accuracy can be improved.
  • first pulley 212, the second pulley 214, the third pulley 222, and the fourth pulley 224 can be operated during the ascent phase of the measurement process to drive the first steel belt 216, the second steel belt 218, and the
  • the steel belt transmission mechanism constituted by the third steel belt 226 and the fourth steel belt 228 transports the mass part 340 to be tested to the drop release point position through the bearing part 330. From the above analysis, it can be known that the recoil effect in the rising stage can be completely eliminated by the steel belt transmission mechanism with the first balancer 310 and the second balancer 320. During the falling stage, the steel belt transmission mechanism and the cam 410 mechanism including the cam 410 and the adjusting member 430 are operated at the same time.
  • the steel belt transmission mechanism is mainly used to realize the long-distance free fall motion of the test mass and partially eliminate the recoil effect.
  • the cam 410 drives the part to be measured to achieve a movement displacement that satisfies the formula (10) to achieve the balance drop mechanism 10 and the overall center of mass of the mass part 340 to be measured to remain unchanged, thereby completely eliminating the recoil effect, thereby achieving improved measurement The purpose of precision.
  • the embodiment of the application also provides a gravimeter.
  • the gravimeter may be an instrument used to measure the absolute value of gravitational acceleration.
  • the gravimeter includes the balance falling mechanism 10.
  • the gravimeter may also include the interferometric measuring device. The displacement time pair of the free fall trajectory of the mass to be measured 340 during the falling process is obtained by the interferometric device, and then the movement state of the mass to be measured 340 can be obtained.

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  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
  • A Measuring Device Byusing Mechanical Method (AREA)

Abstract

一种平衡下落机构和重力仪，驱动装置可以驱动调节件在竖直方向运动。当承载件（330）和待测质量件（340）在竖直方向运动，且待测质量件（340）与承载件（330）分离使待测质量件（340）做自由落体运动时，可以通过质点系动量定理对重力仪整体进行分析，以重力仪整体质心保持不变为控制目标，得出调节件（430）在竖直方向运动的状态，进而可以通过控制调节件（430）的运动状态使得重力仪整体质心保持不变，从而消除反冲振动对测量过程的影响。

Description

平衡下落机构和重力仪
相关申请
本申请要求2020年06月05日申请的，申请号为202010504886.9，名称为“平衡下落机构和重力仪”的中国专利申请的优先权，在此将其全文引入作为参考。
技术领域
本申请涉及精密仪器技术领域，特别是涉及一种平衡下落机构和重力仪。
背景技术
在高精度绝对重力测量领域中，经典的自由落体式绝对重力仪采用稳频激光干涉测量技术，通过在精密测量真空环境下测试质量作自由落体运动的位移和时间，最后拟合自由落体运动参数来得到绝对重力加速度。因此自由落体运动位移的精密测量是获取高精度绝对重力加速度值的关键。实际上，自由落体运动期间的测量过程经常受到来自仪器本身和仪器支撑座的振动噪声的干扰，而振动噪声的干扰会影响绝对重力测量的精度。重力仪传动机构在实现测试质量自由落体运动的过程中所引起的仪器自身反冲振动是影响最大的一种振动干扰，从而会在重力测量中引入系统偏差。
发明内容
基于此，有必要针对上述问题，提供一种平衡下落机构和重力仪。
一种平衡下落机构，包括：
壳体，包围形成容纳腔，所述容纳腔具有竖直的中心对称轴；
第一转动机构和第二转动机构，设置于所述容纳腔内，并关于所述中心对称轴对称设置于所述中心对称轴的两侧；
第一平衡件和第二平衡件，设置于所述容纳腔内，分别与所述第一转动机构和所述第二转动机构传动连接，并对称设置于所述中心对称轴的两侧；
承载件，用于放置待测质量件，所述承载件设置于所述中心对称轴，并与所述第一转动机构和所述第二转动机构传动连接；
所述第一转动机构和所述第二转动机构用于驱动所述承载件与所述第一平衡件和所述第二平衡件以相同的速率在竖直方向朝相反的方向运动；
驱动装置，设置于所述壳体；
调节件，与所述驱动装置传动连接，所述驱动装置用于驱动所述调节件在竖直方向运动，以使所述待测质量件在所述容纳腔中作自由落体运动时使所述重力仪整体质心保持不变。
在一个实施例中，所述驱动装置包括：
凸轮，竖直转动设置于所述壳体的顶部；
滑轨，竖直设置于所述壳体的顶部，所述调节件滑动设置于所述滑轨，并与所述凸轮抵接，所述凸轮转动时驱动所述调节件沿着所述滑轨在竖直方向运动。
在一个实施例中，所述凸轮根据所述待测质量件的质量、所述调节件的质量、所述承载件的位移和所述待测质量件的位移，确定所述调节件在竖直方向的位移。
在一个实施例中，所述驱动装置包括底座和支撑板，沿着竖直方向间隔设置于所述壳体的顶部，所述滑轨设置于所述底座和所述支撑板之间。
在一个实施例中，所述支撑板设置有开孔，用于通过所述调节件。
在一个实施例中，所述驱动装置还包括支撑座，设置于所述底座，所述凸轮转动设置于所述支撑座。
在一个实施例中，所述驱动装置包括丝杆，所述丝杆竖直转动设置于所述壳体的顶部，所述调节件为螺母，所述螺母与所述丝杆螺纹配合，所述丝杆转动时驱动所述螺母在竖直方向运动。
在一个实施例中，还包括两个单侧齿条和一个双侧齿条，所述第一转动机构和所述第二转动机构均为齿轮，所述第一平衡件和第二平衡件分别通过一个所述单侧齿条与一个所述齿轮传动连接，所述承载件通过所述双侧齿条与两个所述齿轮传动连接。
在一个实施例中，所述第一转动机构包括：
沿着竖直方向设置的第一滑轮和第二滑轮；
第一钢带和第二钢带，所述第一钢带的两端分别与所述第一平衡件和所述承载件连接，所述第二钢带的两端分别与所述第一平衡件和所述承载件连接，所述第一钢带、所述第二钢带、所述第一平衡件和所述承载件构成围绕所述第一滑轮和所述第二滑轮的闭环；
所述第二转动机构包括：
沿着竖直方向设置的第三滑轮和第四滑轮；
第三钢带和第四钢带，所述第三钢带的两端分别与所述第二平衡件和所述承载件连接，所述第四钢带的两端分别与所述第二平衡件和所述承载件连接，所述第三钢带、所述第四钢带、所述第二平衡件和所述承载件构成围绕所述第三滑轮和所述第四滑轮的闭环。
在一个实施例中，还包括伺服电机，与所述第一滑轮、第二滑轮、第三滑轮或者第四滑轮之一传动连接。
一种重力仪，包括所述的平衡下落机构。
本申请实施例提供的所述平衡下落机构，所述驱动装置可以驱动所述调节件在竖直方向运动。当所述承载件和所述待测质量件在竖直方向运动，且所述待测质量件与所述承载件分离使所述待测质量件做自由落体运动时，可以通过质点系动量定理对所述平衡下落机构整体进行分析，以所述平衡下落机构的整体质心保持不变为控制目标，得出所述调节件在竖直方向运动的状态。进而可以通过控制所述调节件的运动状态使得所述平衡下落机构整体质心保持不变，从而消除所述反冲振动对绝对重力测量过程的影响，提高测量精度。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请实施例提供的平衡下落机构示意图；
图2为本申请实施例提供的驱动装置立体示意图；
图3为本申请实施例提供的驱动装置正视图；
图4为本申请实施例提供的凸轮结构正视图；
图5为本申请实施例提供的凸轮结构剖面图；
图6为本申请另一个实施例提供的螺丝螺杆结构示意图；
图7为本申请另一个实施例提供的齿轮齿条结构示意图。
附图标记说明：
平衡下落机构10
壳体100
容纳腔110
中心对称轴120
第一转动机构210
第一滑轮212
第二滑轮214
第一钢带216
第二钢带218
第二转动机构220
第三滑轮222
第四滑轮224
第三钢带226
第四钢带228
第一平衡件310
第二平衡件320
承载件330
待测质量件340
驱动装置400
凸轮410
滑轨420
滑杆421
调节件430
线性轴承431
支撑板440
开孔442
底座450
支撑座460
丝杆470
安装单元480
单侧齿条510
双侧齿条520
具体实施方式
为使本申请的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本申请。但是本申请能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本申请内涵的情况下做类似改进，因此本申请不受下面公开的具体实施例的限制。
在本申请的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本申请中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系，除非另有明确的限定。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一 特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
需要说明的是，当元件被称为“固定于”或“设置于”另一个元件，它可以直接在另一个元件上或者也可以存在居中的元件。当一个元件被认为是“连接”另一个元件，它可以是直接连接到另一个元件或者可能同时存在居中元件。本文所使用的术语“垂直的”、“水平的”、“上”、“下”、“左”、“右”以及类似的表述只是为了说明的目的，并不表示是唯一的实施方式。
参阅图1，本申请实施例提供一种平衡下落机构10。所述平衡下落机构10包括壳体100、第一转动机构210、第二转动机构220、第一平衡件310、第二平衡件320、承载件330、驱动装置400和调节件430。所述壳体100包围形成容纳腔110。所述容纳腔110具有竖直的中心对称轴120。所述第一转动机构210和第二转动机构220设置于所述容纳腔110内。所述第一转动机构210和第二转动机构220关于所述中心对称轴120对称设置于所述中心对称轴120的两侧。所述第一平衡件310和所述第二平衡件320收纳于所述容纳腔110中。所述第一平衡件310和所述第二平衡件320分别与所述第一转动机构210和所述第二转动机构220传动连接。所述第一平衡件310和所述第二平衡件320对称设置于所述中心对称轴120的两侧。所述承载件330用于放置待测质量件340。所述承载件330设置于所述中心对称轴120。所述承载件330与所述第一转动机构210和所述第二转动机构220传动连接。所述第一转动机构210和所述第二转动机构220可以驱动所述承载件330与所述第一平衡件310和所述第二平衡件320以相同的速率在竖直方向朝相反的方向运动。
所述驱动装置400设置于所述壳体100的顶部。所述调节件430与所述驱动装置400传动连接。所述驱动装置400能够驱动所述调节件430在竖直方向运动，以使所述待测质量件340在所述容纳腔110中做自由落体时使所述平衡下落机构10整体质心保持不变。
所述壳体100可以为立方体结构。所述容纳腔110中可以为真空。在真空环境中，减少物体下降时产生的空气阻力较小。在一个实施例中，所述容纳腔110可以为超真空环境。在超真空环境下得到自由落体轨迹的位移时间对，再利用公式S＝1/2gt 2对这一系列位移时间对进行拟合得到的二次项，获得的重力加速度更为准确。
所述第一转动机构210和第二转动机构220可以设置于同一水平线上。所述第一转动机构210和所述第二转动机构220可以通过自转带动所述第一平衡件310、所述第二平衡件320、所述承载件330在竖直方向向上或者向下运动。所述第一转动机构210和第二转 动机构220可以为具有一定质量的配重块。所述第一转动机构210和所述第二转动机构220的可以均为圆形结构。所述圆形结构的直径可以相同。
所述承载件330可以通过所述第一转动机构210和所述第二转动机构220与所述第一平衡件310和所述第二平衡件320联动。可以理解，当左侧的所述第一转动机构210逆时针转动，右侧的所述第二转动结构220顺时针同速转动时，所述承载件330在竖直方向上升，所述第一平衡件310和所述第二平衡件320在竖直方向同速下降。当所述第一转动机构210顺时针转动，所述第二转动结构220逆时针同速转动时，所述第一转动机构210和所述第二转动机构220可以带动所述第一平衡件310和所述第二平衡件320在竖直方向同步上升。同时，所述承载件330在竖直方向同速下降。所述承载件330上放置的所述待测质量件340与之分离并做自由落体运动。可以通过测量所述待测质量件340下落轨迹的位移时间对，来计算当地的重力加速度。
可以理解，所述第一平衡件310、所述第二平衡件320的质量之和可以等于所述承载件330和放置于所述承载件330的待测质量件340之和。当需要测量重力加速度时，可以先使得所述承载件330带动所述待测质量件340上升。当上升到一定高度后，可以控制所述承载件330以大于g的加速度向下加速，使得所述承载件330和所述待测质量件340分离。此时所述待测质量件340开始作自由落体运动。
可以理解，通过控制所述承载件330的下降速度，可以控制所述承载件330与所述待测质量件340的分离距离保持在一设定范围内。在一个实施例中，所述承载件330与所述待测质量件340的之间的距离保持在10mm以内，因此可以减少所述待测质量件340落到所述承载件330时产生较大的冲击力，从而减少冲击对待测质量件340和所述承载件330的损伤，增加零件可重复使用测量的次数。还可以确保所述待测质量件340落在所述承载件330上的位置精度，保证每次下落测量的重复精度。进一步地，可以控制所述承载件330、所述第一平衡件310和所述第二平衡件320之间联动的距离，进而可以控制所述待测质量件340能够自由下落的距离。在一个实施例中，所述待测质量件340自由落体距离大于20cm。在该范围内，测量所述待测质量件340得到的位移时间对数据更多，拟合得到的重力加速度值精度更高，可以达到μGal(10-8m/s2)量级的精度。
当需要停止测量时，可以使得所述承载件330减速然后轻轻接住所述待测质量件340，然后携带所述待测质量件340回到上升的初始位置。
可以理解，所述承载件330和所述待测质量件340分离的瞬间，相当于所述平衡下落机构10的质量突然减小，导致向地面导入一个机械脉冲，产生的动量传递到平衡下落机构10和地面上，从而引起地面的振动以及平衡下落机构10所属的重力仪系统中隔振装置和下落腔室的振动，这种振动噪声称为反冲振动。由于反冲振动在每次下落中复现度很高且相位相近，会给绝对重力测量引入系统误差。
本申请实施例中，所述驱动装置400可以驱动所述调节件430在竖直方向运动。当所述承载件330和所述待测质量件340在竖直方向运动，且所述待测质量件340与所述承载件330分离使所述待测质量件340做自由落体运动时，可以通过质点系动量定理对所述平衡下落机构10整体进行分析，以所述平衡下落机构10整体质心保持不变为控制目标，得出所述调节件430在竖直方向运动的状态。进而可以通过控制所述调节件430的运动状态使得所述平衡下落机构10整体质心保持不变，从而消除所述反冲振动对测量过程的影响。
在一个实施例中，所述承载件330携带所述待测质量件340上升的过程中，所述承载件330和所述待测质量件340作为整体向上运动，所述第一平衡件310和所述第二平衡件320以等大反向的速度向下运动，考虑所述平衡下落机构10与所述待测质量件340组成的系统，由质点系动量定理可得：
∫(F N-G all)dt＝Δp＝m 1Δv 1+m 2Δv 2-m 3Δv 3-m 4Δv 4,       (1)
G all＝(m 1+m 2+m 3+m 4)g,             (2)
F N是所述平衡下落机构10所受的支撑力，m 1,m 2,m 3,m 4分别代表所述待测质量件340、所述承载件330和所述第一平衡件310和所述第二平衡件320的质量，Δp表示任意积分时间段内系统的动量变化，Δv 1,Δv 2,Δv 3,Δv 4分别表示所述待测质量件340、所述承载件330和所述第一平衡件310和所述第二平衡件320在任意积分时间段内的速度变化量。G all为所述待测质量件340、所述承载件330和所述第一平衡件310和所述第二平衡件320所受的重力。
根据上升过程的运动关系，容易得到Δv 1＝Δv 2＝-Δv 3＝-Δv 4。由公式(1)可知，只有在上升过程中任一时刻都保持Δp＝0，支撑力F N才不会发生变化,才不会产生向地面传递反冲动量从而引起反冲振动。因此往公式(1)中代入Δp＝0可得：
m 1+m 2＝m 3+m 4,     (3)
由公式(3)可知，只要保证所述第一平衡件310、所述第二平衡件320的质量和与所述待测质量件340和所述承载件330的质量和相等，就能实现测量过程的上升阶段不存在反冲效应。
同样地，对于下落过程应用质点系动量定理可得：
∫(F N-G all)dt＝Δp＝-m 1Δv 1-m 2Δv 2+m 3Δv 3+m 4Δv 4,      (4)
由于下落过程所述承载件330与所述待测质量件340分离，两者做不同运动，而所述第一平衡件310和所述第二平衡件320的速度与所述承载件330的速度大小相等方向相反，因此四者的速度关系满足v 1(t)≠v 2(t)＝-v 3(t)＝-v 4(t)。结合公式(3)和公式(4)可得
Δp(t)＝∫(F N(t)-G all)dt＝m 1·∫[a 1(t)-a 2(t)]dt         (5)
其中a 1(t),a 2(t)分别为所述待测质量件340和所述承载件330在下落过程中的加速度。所述待测质量件340作自由落体运动，所以a 1(t)＝g是个常量。而所述承载件330下落过程加速度a 2(t)是一个随时间变化的量。由前述可知释放时刻存在a 2(t)>g以实现所述待测质量件340与所述承载件330的分离，所述承载件330接住所述待测质量件340前则有a 2(t)<g以保证所述承载件330能轻轻接住所述待测质量件340。因此下落过程中a 1(t)-a 2(t)的值随时间变化。根据公式(5)可知无法保证Δp(t)＝0在下落过程的任意时刻都满足。
根据质点系动量定理推出，仅仅上述系统无法实现下落过程反冲振动的完全消除。重新考虑所述第一平衡件310、所述第二平衡件320、所述待测质量件340、所述承载件330和和所述调节件430组成的整体。以所述测试质量件、所述承载件330、所述第一平衡件310、所述第二平衡件320和所述调节件430为研究对象，则公式(5)可改写为：
Δp(t)＝∫(F N-G all)dt＝∫[m 2·a 2(t)-m 1·a 1(t)+m 5·a 5(t)]dt     (6)
G all)＝(m 1+m 2+m 3+m 4+m 5)g,    (7)
其中m 5和a 5(t)分别为所述调节件430的质量和下落过程中所述调节件430的加速度。为了实现完全的反冲平衡，将Δp(t)＝0代入公式(6)可得公式(8)，其中v 5(t)为滑块的运动速度：
m 1·v 2(t)-m 1·v 1(t)+m 5·v 5(t)＝0,           (8)
公式(8)等号两边同时积分可得：
m 1·s 2(t)-m 1·s 1(t)+m 5·s 5(t)＝0.         (9)
其中s 1(t),s 2(t),s 5(t)分别为所述待测质量件340、所述承载件330和所述调节件430的运动位移。由于实际运动过程中这些位移均是对时间可导的函数，因此对公式(9)求导也能推出公式(8)。这说明满足公式(9)等价于满足公式(8)，均能实现下落过程中任意时刻Δp(t)＝0。因此公式(9)即为滑块5所需满足的运动条件，进一步可整理为：
s 5(t)＝-m 1/m 5·[s 2(t)-s 1(t)].    (10)
根据公式(10)可知，下落过程中所述调节件430的运动位移与所述待测质量件340和所述承载件330的分离距离s 2(t)-s 1(t)相关。实际测量过程中，可以通过伺服电机控制所述第一转动机构210和所述第二转动机构220的转速。所述承载件330的运动位移s 2(t)可由伺服电机的光轴编码器获得，所述待测质量件340的运动位移s 1(t)可由自由落体公式s 1(t)＝1/2·gt 2近似估计。
其中，所述平衡下落机构10可以适用于重力仪。所述重力仪可以为绝对重力仪。所述绝对重力仪可以通过干涉测量装置获得下落过程中所述待测质量件340自由落体轨迹的位移时间对。其中位移干涉测量原理与迈克尔逊干涉仪相近，所述干涉测量装置可以包括激光器、角锥棱镜、分束器、光电探测器。所述激光器发出的光束通过分束器分为测量光和参考光，其中测量光向上传播经过所述待测质量件340内部固定的角锥棱镜和参考角锥棱镜的反射最终与参考光汇合发生干涉，包含下落位移信息的干涉条纹信号被所述光电探测器获取。因此理论上干涉测量得到的下落位移为所述待测质量件340相对于参考棱镜的运动位移。因此所述待测质量件340的运动位移s 1(t)也可由下落干涉条纹获得。因此，可以得到所述调节件430的运动位移。通过控制所述调节件430的位移满足公式(10)，既可以达到保持所述平衡下落机构10整体质心保持不变的效果。
可以理解，所述平衡下落机构10也可以适用于其它需要平衡反冲振动的机构。
请参见图2和图3，在一个实施例中，所述驱动装置400包括凸轮410和滑轨420。所述凸轮410竖直转动设置于所述壳体100的顶部。所述滑轨420竖直设置于所述壳体100的顶部。所述调节件430滑动设置于所述滑轨420。并与所述凸轮410抵接。所述凸轮410转动时驱动所述调节件430沿着所述滑轨420在竖直方向运动。可以理解，所述凸轮410转动时，所述凸轮410的轮廓可以确定所述调节件430的位移。可以通过所述调节件430的位移设置所述凸轮410的轮廓和直径，进而可以确保在所述凸轮410转动时使得所 述调节件430的位移满足公式(10)。
在一个实施例中，可以通过伺服电机驱动所述凸轮410转动。伺服电机具有良好的控制精度。在一个实施例中，可以通过所述伺服电机驱动所述凸轮410匀速转动，而通过设置所述凸轮410的轮廓和直径可以确保所述调节件430的位移满足公式(10)。
在一个实施例中，所述驱动装置400包括底座450和支撑板440。所述底座450和所述支撑板440可以沿着竖直方向间隔设置于所述壳体100的顶部。所述滑轨420设置于所述底座450和所述支撑板440之间。
所述底座450和所述支撑板440可以均为圆盘结构。所述底座450和所述支撑板440可以平行设置。所述滑轨420包括两个滑杆421，所述两个滑杆421间隔设置于所述底座450和所述支撑板440之间。所述调节件430的两端分别滑动设置于一个所述滑杆421。所述凸轮410也可以设置于两个所述滑杆421之间。所述凸轮410转动时，可以驱动所述调节件430沿着两个所述滑杆421在竖直方向运动。
请参见图4和图5，在一个实施例中，所述调节件430的两端可以安装有线性轴承431。所述线性轴承431可以分别套在所述一个滑杆421的外侧。
在一个实施例中，所述支撑板440设置有开孔442。用于通过所述调节件430。所述开孔442的形状可以为方形或者圆形等。所述凸轮410驱动所述调节件430上下移动时，所述调节件430可以从所述开孔442穿过，因此可以提高所述调节件430的行程范围。
在一个实施例中，所述驱动装置400还包括支撑座460。所述支撑座460设置于所述底座450，所述凸轮410转动设置于所述支撑座460。
请参见图6，所述驱动装置400包括丝杆470。所述丝杆470竖直转动设置于所述壳体100的顶部。所述调节件430为螺母。所述螺母与所述丝杆470螺纹配合。所述丝杆470转动时驱动所述螺母在竖直方向运动。
可以理解，所述丝杆470可以通过伺服电机控制。通过控制伺服电机的转速即可以控制所述丝杆470的转速，进而可以控制所述螺母在竖直方向的位移。通过设置伺服电机的程序可以控制所述丝杆470的转速，进而使得所述调节件430的位移满足上述要求。在一个实施例中，所述丝杆470的两端可以分别设置一个安装单元480，所述伺服电机可以通过一个安装单元驱动所述丝杆470转动。
请参见图7，在一个实施例中，所述平衡下落机构10还包括两个单侧齿条510和一个 双侧齿条520。所述第一转动机构210和第二转动机构220均为齿轮。所述第一平衡件310和所述第二平衡件320分别通过一个所述单侧齿条510与一个所述齿轮传动连接。所述承载件330通过所述双侧齿条520与两个所述齿轮传动连接。可以理解，所述双侧齿条520可以设置于所述中心对称轴120。所述第一平衡件310和所述第二平衡件320可以分别设置于一个所述单侧齿条510的一端。所述承载件330设置于所述双侧齿条520的一端。所述双侧齿条520位于两个所述齿轮之间，所述双侧齿条520的两侧分别与两个齿轮啮合。
可以理解，当左边的齿轮顺时针转动、右边的齿轮逆时针转动时，所述双侧齿条520携带所述承载件330下降。两个所述单侧齿条510分别携带所述第一平衡件310和所述第二平衡件320上升。通过控制所述齿轮的转速可以控制所述承载件330的运动从而实现所述待测质量件340的上升和下落过程。由于所述单侧齿条510和所述双侧齿条520的长度可以根据需要设置，因此可以保证下落过程中所述待测质量件340的长距离自由落体运动，从而能够提高测量的精确度。
在一个实施例中，所述第一转动机构210包括沿着竖直方向设置的第一滑轮212和第二滑轮214、第一钢带216和第二钢带218。所述第一钢带216的两端分别与所述第一平衡件310和所述承载件330连接。所述第一钢带216可以围绕在所述第一滑轮212的上半圆设置。所述第一钢带216的两端能从所述第一滑轮212的两端对称垂下并分别连接所述第一平衡件310和所述承载件330。
所述第二钢带218的两端分别与所述第一平衡件310和所述承载件330连接。所述第二钢带218可以围绕所述第二滑轮214的下半圆设置。所述第二钢带218的两端可以分别与所述第一平衡件310和所述承载件330连接。因此所述第一钢带216、所述第二钢带218、所述第一平衡件310和所述承载件330构成围绕所述第一滑轮212和所述第二滑轮214的闭环，并且通过所述第一滑轮212和所述第二滑轮214将所述第一钢带216、所述第二钢带218、所述第一平衡件310和所述承载件330构成张紧的闭环结构。
所述第二转动机构220包括沿着竖直方向设置的第三滑轮222和第四滑轮224、第三钢带226和第四钢带228。所述第三钢带226的两端分别与所述第二平衡件320和所述承载件330连接。所述第三钢带226可以绕过所述第三滑轮222的上半圆。所述第三钢带226的两端向下延伸并分别与所述第二平衡件320和所述承载件330连接。
所述第四钢带228的两端绕过所述第四滑轮224并朝上延伸，分别与所述第二平衡件 320和所述承载件330连接。所述第四滑轮224和所述第三滑轮222将所述第四钢带228和所述第三钢带226张紧。因此所述第四钢带228、所述第二平衡件320和所述承载件330构成围绕所述第三滑轮222和所述第四滑轮224的张紧的闭环结构。
在一个实施例中，所述平衡下落机构10还包括伺服电机。所述伺服电机所述第一滑轮212、第二滑轮214、第三滑轮222或者第四滑轮224之一传动连接。即只要所述第一滑轮212、所述第二滑轮214、所述第三滑轮222或者所述第四滑轮224有一个转动，在所述第一钢带216、所述第二钢带218、所述第三钢带226或者所述第四钢带228的带动下，其它剩余的滑轮都会随之转动。因此可以控制所述承载件330产生向上或者向下的位移。在一个实施例中，所述伺服电机与所述第四滑轮224传动连接。因此，所述第四滑轮224转动时，会通过所述第三钢带226和所述第四钢带228带动所述第三滑轮222转动。同时，所述承载件330也会转动，并通过所述承载件330带动所述第一钢带216和所述第二钢带218转动。所述第一钢带216和所述第二钢带218转动可以带动所述第一滑轮212和所述第二滑轮214转动。
可以理解，通过设置所述第一滑轮212和所述第二滑轮214之间的距离，以及所述第三滑轮222和所述第四滑轮224之间的距离，可以增加所述承载件330上升或者下降的距离。因此可以起到增加所述待测质量件340自由落体的距离，增加数据采集的量，从而可以提高测量精度。
可以理解，测量过程的上升阶段仅可以仅运行第一滑轮212、第二滑轮214、第三滑轮222和第四滑轮224带动所述第一钢带216、所述第二钢带218、所述第三钢带226和所述第四钢带228构成的钢带传动机构，通过所述承载件330将所述待测质量件340托送至下落释放点位置。由上述分析可知，该上升阶段的反冲效应，可以由带所述第一平衡件310和所述第二平衡件320的钢带传动机构完全消除。下落阶段则同时运行钢带传动机构和包括凸轮410和调节件430的凸轮410机构，其中所述钢带传动机构主要用于实现测试质量长距离的自由落体运动并可部分消除反冲效应，所述凸轮410带动所述待测件实现满足公式(10)的运动位移以实现所述平衡下落机构10和所述待测质量件340整体质心保持不变从而完全消除反冲效应，从而达到提高测量精度的目的。
本申请实施例还提供一种重力仪。所述重力仪可以是用来测量重力加速度绝对值的仪器。所述重力仪包括所述平衡下落机构10。所述重力仪还可以包括所述干涉测量装置。通 过所述干涉测量装置获得下落过程中所述待测质量件340自由落体轨迹的位移时间对，进而可以获得所述待测质量件340的运动状态。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。
最后，还需要说明的是，在本文中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。
本说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。
对所公开的实施例的上述说明，使本领域专业技术人员能够实现或使用本申请。对这些实施例的多种修改对本领域的专业技术人员来说将是显而易见的，本文中所定义的一般原理可以在不脱离本申请的精神或范围的情况下，在其它实施例中实现。因此，本申请将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。

Claims (11)

  1. 一种平衡下落机构，其特征在于，包括：
    壳体(100)，包围形成容纳腔(110)，所述容纳腔(110)具有竖直的中心对称轴(120)；
    第一转动机构(210)和第二转动机构(220)，设置于所述容纳腔(110)内，并关于所述中心对称轴(120)对称设置于所述中心对称轴(120)的两侧；
    第一平衡件(310)和第二平衡件(320)，设置于所述容纳腔(110)内，分别与所述第一转动机构(210)和所述第二转动机构(220)传动连接，并对称设置于所述中心对称轴(120)的两侧；
    承载件(330)，用于放置待测质量件(340)，所述承载件(330)设置于所述中心对称轴(120)，并与所述第一转动机构(210)和所述第二转动机构(220)传动连接；
    所述第一转动机构(210)和所述第二转动机构(220)用于驱动所述承载件(330)与所述第一平衡件(310)和所述第二平衡件(320)以相同的速率在竖直方向朝相反的方向运动；
    驱动装置(400)，设置于所述壳体(100)；
    调节件(430)，与所述驱动装置(400)传动连接，所述驱动装置(400)用于驱动所述调节件(430)在竖直方向运动，以使所述待测质量件(340)在所述容纳腔(110)中作自由落体运动时使所述重力仪整体质心保持不变。
  2. 如权利要求1所述的平衡下落机构，其特征在于，所述驱动装置(400)包括：
    凸轮(410)，竖直转动设置于所述壳体(100)的顶部；
    滑轨(420)，竖直设置于所述壳体(100)的顶部，所述调节件(430)滑动设置于所述滑轨(420)，并与所述凸轮(410)抵接，所述凸轮(410)转动时驱动所述调节件(430)沿着所述滑轨(420)在竖直方向运动。
  3. 如权利要求2所述的平衡下落机构，其特征在于，所述凸轮(410)根据所述待测质量件(340)的质量、所述调节件(430)的质量、所述承载件(330)的位移和所述待测质量件(340)的位移，确定所述调节件(430)在竖直方向的位移。
  4. 如权利要求2所述的平衡下落机构，其特征在于，所述驱动装置(400)包括底座(450)和支撑板(440)，沿着竖直方向间隔设置于所述壳体(100)的顶部，所述滑轨(420)设置于所述底座(450)和所述支撑板(440)之间。
  5. 如权利要求4所述的平衡下落机构，其特征在于，所述支撑板(440)设置有开孔(442)，用于通过所述调节件(430)。
  6. 如权利要求4所述的平衡下落机构，其特征在于，所述驱动装置(400)还包括支 撑座(460)，设置于所述底座(450)，所述凸轮(410)转动设置于所述支撑座(460)。
  7. 如权利要求1所述的平衡下落机构，其特征在于，所述驱动装置(400)包括丝杆(470)，所述丝杆(470)竖直转动设置于所述壳体(100)的顶部，所述调节件(430)为螺母，所述螺母与所述丝杆(470)螺纹配合，所述丝杆(470)转动时驱动所述螺母在竖直方向运动。
  8. 如权利要求1所述的平衡下落机构，其特征在于，还包括两个单侧齿条(510)和一个双侧齿条(520)，所述第一转动机构(210)和所述第二转动机构(220)均为齿轮，所述第一平衡件(310)和第二平衡件(320)分别通过一个所述单侧齿条(510)与一个所述齿轮传动连接，所述承载件(330)通过所述双侧齿条(520)与两个所述齿轮传动连接。
  9. 如权利要求1所述的平衡下落机构，其特征在于，
    所述第一转动机构(210)包括：
    沿着竖直方向设置的第一滑轮(212)和第二滑轮(214)；
    第一钢带(216)和第二钢带(218)，所述第一钢带(216)的两端分别与所述第一平衡件(310)和所述承载件(330)连接，所述第二钢带(218)的两端分别与所述第一平衡件(310)和所述承载件(330)连接，所述第一钢带(216)、所述第二钢带(218)、所述第一平衡件(310)和所述承载件(330)构成围绕所述第一滑轮(212)和所述第二滑轮(214)的闭环；
    所述第二转动机构(220)包括：
    沿着竖直方向设置的第三滑轮(222)和第四滑轮(224)；
    第三钢带(226)和第四钢带(228)，所述第三钢带(226)的两端分别与所述第二平衡件(320)和所述承载件(330)连接，所述第四钢带(228)的两端分别与所述第二平衡件(320)和所述承载件(330)连接，所述第三钢带(226)、所述第四钢带(228)、所述第二平衡件(320)和所述承载件(330)构成围绕所述第三滑轮(222)和所述第四滑轮(224)的闭环。
  10. 如权利要求9所述的平衡下落机构，其特征在于，还包括伺服电机，与所述第一滑轮(212)、第二滑轮(214)、第三滑轮(222)或者第四滑轮(224)之一传动连接。
  11. 一种重力仪，其特征在于，包括权利要求1-10任一项所述的平衡下落机构。
PCT/CN2021/096792 2020-06-05 2021-05-28 平衡下落机构和重力仪 WO2021244426A1 (zh)

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