An on-line frequency modulation pipeline and shafting dynamic vibration absorber

Abstract

The present invention discloses a pipeline and shafting dynamic vibration absorber with online frequency modulation, belonging to the technical field of vibration and noise control. The device includes a radial clamping member, a spring plate, a screw, a mass block and a bolt; the radial clamping member is fixedly connected to one end of the spring plate, the spring plate is embedded in the guiding square groove of the mass block, the screw passes through the threaded hole on the connecting end of the spring plate and the radial clamping member and the threaded hole on the lower mass block in sequence and then is in clearance fit with the through hole on the other end of the spring plate; the vibration absorber is fixedly connected to the pipeline and shafting dynamic module through the radial clamping member, and the relative sliding of the mass block on the spring plate is controlled by rotating the screw to adjust the stiffness parameter of the dynamic vibration absorber, so as to realize the controllability of the vibration absorption frequency. The present invention can realize the online precise fine adjustment of the vibration absorption frequency, maximize the vibration absorption performance, and simultaneously has the characteristics of fast frequency modulation, wide frequency modulation range, no need for disassembly and assembly during frequency modulation, simple operation and convenient installation.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration and noise control, and particularly relates to a pipeline and shafting dynamic vibration absorber with online frequency modulation. Background Art

[0002] With the improvement of people's requirements for living and working environments and the further pursuit of stealth performance by military ships, the vibration and noise problems of pipeline and shafting systems have become increasingly prominent. Generally speaking, pipeline systems often vibrate due to the vibration of excitation equipment (such as pumps, motors, etc.) and the flow of fluids inside the pipelines. Shafting systems often vibrate at the critical speed resonance due to the unbalance of the shafting structure operation and the misalignment of the shaft center trajectory. Severe vibration and the noise caused by vibration will not only reduce the accuracy of instruments and equipment and the service life of mechanical parts, but even more severe vibration may even damage the mechanical structure, seriously endangering people's lives and property safety. Therefore, reducing harmful vibration is of great significance for industrial production and national defense.

[0003] Currently, the main control methods for pipeline systems include changing the shape of the pipeline, increasing the pipe clamps, installing vibration absorbers, etc. Among them, the dynamic vibration absorber is a passive vibration reduction method that relies relatively less on installation conditions and can effectively solve the vibration problems of pipeline and shafting systems. The dynamic vibration absorber uses an additional subsystem to change the vibration state of the structure or system to be vibration-reduced (collectively referred to as the main system), and transfers the vibration energy from the main system to the subsystem through the redistribution of vibration energy to achieve the purpose of vibration reduction.

[0004] The key to the application of the dynamic vibration absorber is that its natural frequency and the equipment excitation frequency need to be very close or even the same for the vibration reduction effect to be obvious. Under ideal conditions, the vibration of the vibration source can be completely cancelled out. However, for different pipeline and shafting systems, the corresponding excitation frequency range is wide, which brings the disadvantages of various types of dynamic vibration absorbers and a large number of spare parts. At the same time, during the operation of the equipment, due to reasons such as friction and wear, its excitation frequency will shift within a small range, which requires on-site debugging to fully utilize the performance of the dynamic vibration absorber. In this regard, some researchers have proposed variable stiffness and variable mass dynamic vibration absorbers, which achieve the purpose of adjustable frequency by adjusting the effective length of the spring and replacing the mass block. However, the existing adjustable frequency dynamic vibration absorbers have problems such as low adjustment accuracy, unstable frequency modulation, narrow frequency modulation range, the need for disassembly and assembly for frequency modulation, slow frequency modulation speed, and high requirements for the control personnel. Summary of the Invention

[0005] In view of this, the present invention provides a pipeline and shafting dynamic vibration absorber with online frequency modulation, which can achieve precise online fine-tuning of the vibration absorption frequency during the vibration test, maximize the vibration absorption performance, and has the characteristics of fast frequency modulation, wide frequency modulation range, no need for disassembly and assembly during frequency modulation, simple operation, and convenient installation. It can effectively achieve vibration absorption, vibration reduction, and noise reduction for different pipeline and shafting power modules.

[0006] A pipeline and shafting dynamic vibration absorber with online frequency modulation includes a radial clamping member, a spring strip, a screw, an upper mass block, a lower mass block, and a bolt;

[0007] One end of the radial clamping member is fixedly connected to one end of the spring strip. The spring strip is horizontally embedded in a guiding square groove formed after the upper mass block and the lower mass block are fixed up and down. The screw sequentially passes through a threaded hole on the connection end of the spring strip and the radial clamping member and a threaded hole on the lower mass block, and then is in clearance fit with a through hole at the other end of the spring strip. The vibration absorber is fixedly connected to the pipeline and shafting power module through the radial clamping member. By rotating the screw, the relative sliding of the upper and lower mass blocks on the spring strip is controlled to adjust the stiffness parameter of the dynamic vibration absorber, so as to realize the controllability of the vibration absorption frequency.

[0008] Furthermore, the radial clamping member is composed of two semi-ring structures. Both ends of the semi-ring structure extend radially to form connection flanges, and threaded through holes are opened on the flanges. The threaded through holes are cooperated with bolts and nuts for the fastening connection between the two semi-ring structures. A connection part extends from the top of the semi-ring structure, and a threaded hole is opened on the connection part. The threaded hole is cooperated with bolts and nuts for fixed connection with the spring strip, and the axes of the threaded through hole and the threaded hole are parallel.

[0009] Furthermore, the spring strip is composed of two rectangular fixing blocks and two guiding beams. Both ends of the two guiding beams are simultaneously connected to the fixing blocks, and the two guiding beams are parallel to each other. A threaded through hole for connecting the radial clamping member is opened on one of the fixing blocks. A stepped hole for snap connection with the screw is arranged in a direction perpendicular to the axis of the threaded through hole. While the screw is in cooperation with the stepped hole, locking and unlocking are achieved through snap connection. A through hole coinciding with the axis of the stepped hole is arranged on the other fixing block and is connected to the screw to realize the positioning and clamping of the screw.

[0010] Furthermore, two parallel chutes are arranged on the installation plane of the lower mass block, and the cross section of the chutes is square. A semi-cylindrical convex structure is arranged between the two parallel chutes, and a threaded through hole for threaded connection with the screw is arranged on the convex structure.

[0011] Furthermore, a semi-cylindrical groove is arranged on the installation plane of the upper mass block. The semi-cylindrical groove is mutually attached to the convex structure of the lower mass block. After the upper mass block and the lower mass block are fixedly connected to form an integral body, they jointly slide on the guiding beams of the spring strip.

[0012] The present invention also provides a method for adjusting an on-line frequency modulation pipeline and shafting dynamic vibration absorber device. First, mark the vibration absorption frequencies corresponding to different positions of the upper mass block and the lower mass block on the spring leaf. Secondly, determine the vibration absorption frequency according to the excitation frequency of the power module operation. Finally, rotate the screw for adjustment to adjust the upper and lower mass blocks to the corresponding scale positions.

[0013] Beneficial effects:

[0014] 1. The vibration absorber of the present invention includes a radial clamping member, a spring leaf, a screw, an upper mass block, a lower mass block and a bolt. The screw sequentially passes through the threaded hole on the connection end of the spring leaf and the radial clamping member and the threaded hole on the lower mass block, and then is in clearance fit with the through hole at the other end of the spring leaf. By rotating the screw, the relative positions of the upper and lower mass blocks are changed. Without disassembling and assembling the mass blocks, on-line precise fine-tuning of the vibration absorption frequency can be carried out, the frequency modulation is simple and convenient, and the function of on-line frequency adjustment of the dynamic vibration absorber device is effectively realized.

[0015] 2. During the process of carrying out the vibration absorption frequency of the present invention, only the relative positions of the upper and lower mass blocks on the spring leaf need to be changed. Therefore, the diversity of the positions of the upper and lower mass blocks is related to the length of the screw. Therefore, the dynamic vibration absorber device has the characteristic of a wide frequency modulation range. Changing the relative position can change the vibration absorption frequency, making the device have the characteristic of fast frequency modulation.

[0016] 3. The spring leaf of the present invention is composed of two rectangular fixing blocks and two guiding beams. The two ends of the two guiding beams are simultaneously connected to the fixing blocks, and the two guiding beams are parallel to each other; a threaded through hole for connecting the radial clamping member is opened on one of the fixing blocks, and a stepped hole for snap-connecting the screw is provided in the direction perpendicular to the axis of the threaded through hole. While the screw is matched with the stepped hole, locking and unlocking are realized through snap connection. The snap connection replaces the nut to lock the screw, avoiding the cumbersome operation of repeatedly tightening and loosening the nut and then rotating the screw during the adjustment process of the device, and improving the adjustment efficiency.

[0017] 4. The lower mass block of the present invention is provided with two parallel sliding grooves on the installation plane, and the cross section of the sliding groove is square; the guiding beam of the spring leaf is embedded in the sliding groove to play a guiding role for the lower mass block, which can prevent the lower mass block from rotating relative to the axis. This structure can realize the stable linear movement of the lower mass block along the spring leaf; there is an arc-shaped convex structure between the two parallel sliding grooves, and a threaded through hole for threaded connection with the screw is provided on the convex structure, which can accurately convert the rotational movement of the screw into the linear movement of the lower mass block, change the relative position of the lower mass block, and realize the precise fine-tuning of the vibration absorption frequency.

[0018] 5. The semi-circular groove of the upper mass block and the convex structure of the lower mass block of the present invention are mutually attached and connected, which is convenient for positioning and installation, with simple operation, ensuring that the upper and lower mass blocks slide as a whole, and enhancing the stability of the adjustment process.

[0019] 6. The vibration absorption device of the present invention can greatly suppress the vibration of the pipeline and shafting power module, thereby reducing the vibration transmitted from the pipeline and shafting to the base, improving the durability of the system, and enhancing the acoustic stealth performance of the outer casing connected to the base. Brief Description of the Drawings

[0020] Figure 1 is a three-dimensional structural schematic diagram of the online frequency modulation pipeline and shafting dynamic vibration absorption device according to an embodiment of the present invention;

[0021] Figure 2 is an exploded three-dimensional structural schematic diagram of the online frequency modulation pipeline and shafting dynamic vibration absorption device according to an embodiment of the present invention;

[0022] Figure 3 is a front view of the online frequency modulation pipeline and shafting dynamic vibration absorption device according to an embodiment of the present invention;

[0023] Figure 4 is a schematic cross-sectional structure diagram of the spring piece according to an embodiment of the present invention;

[0024] Figure 5 is a schematic structural diagram of the radial clamping member according to an embodiment of the present invention;

[0025] Figure 6 is a schematic structural diagram of the upper mass block according to an embodiment of the present invention;

[0026] Figure 7 is a schematic structural diagram of the lower mass block according to an embodiment of the present invention.

[0027] Among them, 1 - radial clamping member, 2 - screw, 3 - spring piece, 4 - upper mass block, 5 - lower mass block. Detailed Embodiment

[0028] The following takes examples in conjunction with the drawings to describe the present invention in detail.

[0029] The present invention provides an online frequency modulation pipeline and shafting dynamic vibration absorption device, and the vibration absorption device includes a radial clamping member 1, a spring piece 3, a screw 2, an upper mass block 4, a lower mass block 5 and bolts and nuts. The connection relationship between the above parts is as follows: the radial clamping member 1 is fixedly connected to the spring piece 3, the spring piece 3 is connected to the screw 2 and embedded in the square groove of the lower mass block 5, and the threaded hole of the lower mass block 5 passes through the screw and is fixedly connected to the upper mass block 4. Figure 3Then, the relative position relationship of each part of the on-line frequency modulation pipeline and shafting dynamic vibration absorber can be seen. The above are the overall features of this embodiment. The following are the detailed features of each part:

[0030] Figure 4 It shows a schematic cross-sectional view of the structure of the spring leaf 3 in this embodiment. It can be seen that two threaded through holes and a stepped hole are opened at one end of the spring leaf 3, and a through hole coinciding with the axis of the stepped hole is provided at the other end. Since the on-line frequency modulation pipeline and shafting dynamic vibration absorber usually works in a dynamic load environment, the spring leaf 3 is made of spring steel material with good elasticity and high yield strength. Specifically, the overall shape of the spring leaf 3 is composed of two rectangular fixing blocks at both ends and two guide beams in the middle. The diameters of the two threaded through holes on the right fixing block are 5 mm, the diameters of the stepped holes are 8 mm and 10 mm respectively, and the depths of the stepped holes are 11 mm and 7 mm respectively. The diameter of the through hole on the left fixing block is 6 mm. The thickness, width and length of the guide beam are 3 mm, 7 mm and 120 mm respectively.

[0031] Figure 5 It shows a schematic view of the structure of the radial clamping member 1 in this embodiment. The radial clamping member is composed of two half-ring structures. At both ends of the half-ring structure, connecting flanges extend radially. Threaded through holes are opened on the flanges, and the threaded through holes are matched with bolts and nuts for fastening connection between the two half-ring structures; a connecting portion extends from the top of the half-ring structure, and a threaded hole is opened on the connecting portion. The threaded hole is matched with bolts and nuts for fixed connection with the spring leaf. The axes of the threaded through holes and the threaded hole are parallel. Four threaded holes are opened on the radial clamping member 1, and their axis directions are parallel. Two of the threaded through holes are matched with bolts and nuts for fastening connection between a pair of radial clamping members, and the other two threaded holes are matched with bolts and nuts for fixed connection with the spring leaf 3, so that the vibration energy of the pipeline and shafting dynamic module can be transmitted to the dynamic vibration absorber to achieve the effect of vibration reduction. Since the mass of the absorber structure of the pipeline and shafting dynamic module needs to be as small as possible, the radial clamping member 1 is made of aluminum alloy material with a small density. Specifically, the inner arc surface radius of the radial clamping member 1 is 20 mm, the outer arc surface radius is 24 mm, the diameter of the threaded hole connected to the spring leaf 3 is 5 mm, and the diameter of the threaded hole for connection between a pair of the radial clamping members is 6 mm. At the same time, in order to ensure that the radial clamping member 1 can stably clamp the pipeline and shafting dynamic module, the inner arc surface of the radial clamping member 1 is slightly smaller than the arc surface of a semi-circle.

[0032] Figure 6Shows the schematic structural diagram of the upper mass block 4 in this embodiment. The upper mass block 4 is provided with two threaded through holes for fastening connection with the lower mass block 5, and at the same time, a semi-circular through hole is provided for fitting connection with the lower mass block 5. The material of the upper mass block 4 is 45 steel. Specifically, the diameter of the two threaded through holes is 6 mm, and the radius and depth of the semi-circular through hole are 6 mm and 30 mm respectively.

[0033] Figure 7 Shows the schematic structural diagram of the lower mass block 5 in this embodiment. The lower mass block 5 is provided with two parallel chutes. The cross-section of the chutes is square. The guiding beam of the spring plate 3 can be embedded in the chutes to guide and limit the lower mass block 5. This chute structure can enable the lower mass block 5 to perform stable linear motion along the spring plate. A semi-cylindrical protrusion is provided on the lower mass block 5 so that it can be in fitting connection with the upper mass block 4, facilitating positioning and installation. At the same time, a threaded through hole is provided between the two parallel chutes for threaded connection with the screw rod, which can accurately convert the rotational motion of the screw rod into the linear motion of the lower mass block. The material of the lower mass block 5 is 45 steel. Specifically, the diameter of the two threaded through holes is 6 mm, the length, width, and height of the two square chutes are 30 mm, 7 mm, and 3 mm respectively, the diameter of the threaded hole connected to the screw rod 2 in the middle is 6 mm, and the radius of the semi-cylindrical protrusion is 6 mm.

[0034] The frequency modulation principle of the dynamic vibration absorber device in the embodiment of the present invention is as follows:

[0035] According to the simplified frequency equation of the vibration absorber device (where E is the material elastic modulus, I is the moment of inertia of the spring plate cross-section, M is the mass of the upper and lower mass blocks, and L is the distance between the centroid of the upper and lower mass blocks and the fixed end of the spring plate), it can be seen that when the material is selected, the parameter E remains unchanged; when the spring plate is selected, the parameter I remains unchanged; when the upper and lower mass blocks are selected, the mass M remains unchanged. Since the upper and lower mass blocks can perform linear movement along the spring plate 3, that is, the upper and lower mass blocks can be at any position on the screw rod 2, thus L can be adjusted to adjust the stiffness parameter of the dynamic vibration absorber device and achieve the controllability of the vibration absorption frequency. The adjustment accuracy of the parameter L depends on the pitch of the thread. Since the pitch of the thread is very small, online precise fine-tuning of the vibration absorption frequency can be achieved.

[0036] The specific assembly steps of the dynamic vibration absorber device in this embodiment are as follows:

[0037] (1) Use bolts and nuts to fixedly connect a pair of radial clamping members 1;

[0038] (2) Use bolts and nuts to tightly connect one end of the spring plate 3 with the radial clamping member 1;

[0039] (3) Then embed the guiding beam of the spring plate 3 into the sliding groove of the lower end mass block 5. At the same time, pass the screw 2 through the stepped hole of the rectangular fixing block at the right end of the spring plate 3, the threaded hole of the lower end mass block 4, and the through hole of the rectangular fixing block at the left end of the spring plate 3 in sequence, and make a snap connection with the spring plate;

[0040] (4) Finally, use bolts and nuts to tightly connect the upper end mass block 4 and the lower end mass block 5.

[0041] The usage method of the dynamic vibration absorber in this embodiment is as follows:

[0042] First, determine the vibration absorption frequency according to the excitation frequency of the pipeline and shafting power module during operation. Secondly, determine the position marked on the spring plate corresponding to the vibration absorption frequency, that is, the positions where the upper and lower end mass blocks are located. Then rotate the screw to control the upper and lower end mass blocks to move to the corresponding positions. Finally, connect the on-line frequency modulation pipeline and shafting dynamic vibration absorber to the pipeline and shafting power module, so that the vibration energy of the pipeline and shafting power module is transmitted to the dynamic vibration absorber to achieve the effect of vibration reduction. During the actual vibration test process, if there is a certain error, the positions of the upper and lower end mass blocks on the spring plate can be further finely adjusted, that is, by changing the natural frequency of the vibration absorber to make it as close as possible to the excitation frequency of the pipeline and shafting power module, realizing the on-line precise fine adjustment of the vibration absorption frequency during the vibration test process, which has the characteristics of fast frequency modulation, wide frequency modulation range, no need to disassemble and assemble for frequency modulation, simple operation, and convenient installation. It is suitable for vibration reduction work under the working frequencies of different pipelines and shafting power modules, can improve the reliability and durability of the system, and enhance the acoustic stealth performance of the outer casing connected to the base.

[0043] In summary, the above is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An on-line frequency modulation pipeline and shafting dynamic vibration absorber, characterized in that, It includes a radial clamping member, a spring plate, a screw, an upper end mass block, a lower end mass block and a bolt; The radial clamping member is fixedly connected to one end of the spring plate. The spring plate is horizontally embedded in the guiding square groove formed after the upper end mass block and the lower end mass block are fixed up and down. The screw sequentially passes through the threaded hole on the connection end of the spring plate and the radial clamping member and the threaded hole on the lower end mass block, and then is in clearance fit with the through hole on the other end of the spring plate; The vibration absorption device is fixedly connected to the pipeline and the shafting power module through the radial clamping member. By rotating the screw, the relative sliding of the upper and lower end mass blocks on the spring plate is controlled to adjust the stiffness parameter of the dynamic vibration absorption device, so as to realize the controllability of the vibration absorption frequency; The spring plate is composed of two rectangular fixing blocks and two guiding beams. The two ends of the two guiding beams are simultaneously connected to the fixing blocks, and the two guiding beams are parallel to each other; A threaded through hole for connecting the radial clamping member is opened on one of the fixing blocks, and a stepped hole for snap-connecting the screw is arranged in the direction perpendicular to the axis of the threaded through hole. While the screw is matched with the stepped hole, locking and unlocking are realized through snap connection. A through hole coinciding with the axis of the stepped hole is arranged on the other fixing block and is connected to the screw to realize the positioning and clamping of the screw.

2. The on-line frequency modulation pipeline and shafting dynamic vibration absorber device according to claim 1, characterized in that, The radial clamping member is composed of two semi-ring structures. The two ends of the semi-ring structure extend radially to form connection flanges, and threaded through holes are opened on the flanges. The threaded through holes are matched with bolts and nuts for the fastening connection between the two semi-ring structures; A connecting part extends from the top of the semi-ring structure, and a threaded hole is opened on the connecting part. The threaded hole is matched with bolts and nuts for fixed connection with the spring plate, and the axes of the threaded through hole and the threaded hole are parallel.

3. The on-line frequency modulation pipeline and shafting dynamic vibration absorber device according to claim 1, characterized in that, Two parallel chutes are arranged on the installation plane of the lower end mass block, and the cross section of the chutes is square; A semi-cylindrical convex structure is arranged between the two parallel chutes, and a threaded through hole for threaded connection with the screw is arranged on the convex structure.

4. The on-line frequency modulation pipeline and shafting dynamic vibration absorber device according to claim 2 or 3, characterized in that, A semi-cylindrical groove is arranged on the installation plane of the upper end mass block. The semi-cylindrical groove is mutually attached to the convex structure of the lower end mass block. After the upper end mass block and the lower end mass block are fixedly connected to form a whole, they jointly slide on the guiding beam of the spring plate.

5. A method for adjusting a pipeline and shafting dynamic vibration absorber with online frequency modulation, which is implemented based on the dynamic vibration absorber described in claim 1, and is characterized in that, First, mark the vibration absorption frequencies corresponding to different positions of the upper end mass block and the lower end mass block on the spring plate. Secondly, determine the vibration absorption frequency according to the excitation frequency of the power module operation. Finally, rotate the screw for adjustment to adjust the upper and lower end mass blocks to the corresponding scale positions.

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