Hydraulic shock absorber

Abstract

The utility model discloses a hydraulic shock absorber, including main part assembly, including bottom plate, is fixed with at least two lower guide column on the bottom plate, drive shock attenuation subassembly, including fixedly connected on the displacement sensor of bottom plate upside, the oil tank with oil cavity is slidably connected on the lower guide column, and the one end of oil tank is opened to and a plurality of lower guide column one -to -one corresponding sliding sink, and the oil tank is slidably connected on the corresponding lower guide column through sliding sink, and the oil tank is opened to the adjusting groove on the oil tank at oil cavity, and the oil tank is slidably connected with piston block through adjusting groove, and the flange disc that is one -to -one corresponding with adjusting groove is fixedly connected with the oil tank outside, and the reset spring is connected between the inside of flange disc and the one side of piston block outward.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic shock absorption technology, and in particular to a hydraulic shock absorber. Background Technology

[0002] Laboratories typically house numerous mechanical devices, with precision instruments (such as optical microscopes, electron microscopes, or chromatographic analyzers) resting on workbenches. When these devices are activated, they generate significant vibrations, which in turn vibrate the floor and transmit the vibrations to the precision instruments via the workbench. These instruments may also vibrate during transport. Such vibrations can affect the measurement accuracy of precision instruments. Current technology often places these instruments on hydraulic shock absorbers to reduce vibration. Existing hydraulic shock absorbers primarily rely on the flow resistance of hydraulic oil through damping orifices to reduce vibration. However, when low-frequency impacts occur, the fixed orifice size prevents adjustment of the flow area for low-frequency conditions. The slow flow velocity of the hydraulic oil through the orifices results in a weak damping force, insufficient to offset the energy of low-frequency impacts, thus failing to attenuate the vibration. Utility Model Content

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0004] In view of the problems existing in the above and / or existing hydraulic shock absorbers, this utility model is proposed.

[0005] Therefore, the problem that this invention aims to solve is that traditional shock absorbers cannot attenuate low-frequency impact vibrations. This invention uses a movable piston block to directly adjust the oil chamber volume, thereby preventing the impact from being transmitted to the outside.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a hydraulic shock absorber, comprising,

[0007] The main component includes a base plate, on which at least two lower guide posts are fixed;

[0008] The active damping assembly includes a displacement sensor fixedly connected to the upper side of the base plate, an oil tank with an oil cavity slidably connected to the lower guide column, a sliding groove corresponding to several lower guide columns at the lower end of the oil tank facing downwards, the oil tank being slidably connected to the corresponding lower guide column via the sliding groove, an adjustment groove on the oil tank at the oil cavity, a piston block being slidably connected to the oil tank via the adjustment groove, a flange corresponding to each adjustment groove being fixedly connected to the outside of the oil tank, and a return spring connecting the inside of the flange and the outward side of the piston block.

[0009] In a preferred embodiment of the hydraulic shock absorber of this utility model, a splined drive shaft is rotatably connected to the center of the oil tank, a driven rod is fixedly connected to the inner end of the piston block, and a plurality of cams corresponding one-to-one with the driven rods are connected to the splined drive shaft. The driven rods are always in contact with the outer periphery of the cams under the action of the return spring.

[0010] As a preferred embodiment of the hydraulic shock absorber in this utility model, the oil tank has a mounting groove at its downward end, and a drive motor is fixedly connected to the oil tank via the mounting groove. An output shaft is connected to the drive motor, and the upper end of the output shaft extends into the oil chamber. A spline drive shaft is fixedly connected to the output shaft extending into the oil chamber.

[0011] As a preferred embodiment of the hydraulic shock absorber in this utility model, it further includes a passive shock absorption assembly. The passive shock absorption assembly includes a hydraulic tank body disposed above the oil tank and a passive piston fixedly connected to the upper side of the oil tank. Several upper guide columns are fixedly connected to the upper side of the oil tank, and the hydraulic tank body is slidably connected to the several upper guide columns. The upper part of the passive piston extends into the hydraulic tank body, and the center of the hydraulic tank body can slide up and down along the passive piston.

[0012] As a preferred embodiment of the hydraulic shock absorber in this utility model, at least one lower piston rod is fixedly connected to the upper side of the base plate, and the upper end of the lower piston rod can extend into the oil chamber.

[0013] As a preferred embodiment of the hydraulic shock absorber in this utility model, the spline drive shaft has a number of spline keyways arranged on it, the number of spline keyways being an integer multiple of the number of cams, the inner side of the cam has a number of internal spline teeth that correspond one-to-one with the spline keyways, the cam is sleeved on the spline drive shaft, the internal spline teeth are just inserted into the spline drive shaft through the spline keyways, and the lowermost cam is attached to the shoulder of the spline drive shaft on the lower side of the spline keyway.

[0014] In a preferred embodiment of the hydraulic shock absorber of this utility model, a shim is connected to the splined drive shaft between adjacent cams.

[0015] In a preferred embodiment of the hydraulic shock absorber of this utility model, the number of cams is four.

[0016] Compared with the prior art, this utility model has the following technical effects: the return spring is always in a compressed state; when the worktable is impacted, its upper surface will adapt to the vibration, the base plate is impacted along with the worktable, and the end of the lower piston rod that extends into the oil chamber slides in the oil chamber, causing the volume of the oil chamber to change. The displacement sensor detects the displacement change of the upper surface of the worktable in real time, and the displacement sensor transmits the displacement change signal to the external controller. The external controller controls the drive motor to operate according to the received displacement change signal, the output shaft rotates, and drives the cam to rotate through the spline transmission shaft. When the cam rotates, the driven rod moves accordingly, the volume of the oil chamber is actively adjusted, the volume of the oil chamber is restored, and the impact is prevented from being transmitted to the outside, thus reducing the vibration impact on the precision instrument. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:

[0018] Figure 1 This is the front view of the hydraulic shock absorber.

[0019] Figure 2 This is a top view of a hydraulic shock absorber.

[0020] Figure 3 for Figure 2 View from point AA.

[0021] Figure 4 for Figure 2 View from point BB.

[0022] Figure 5 This is a three-dimensional structural diagram of the hydraulic tank with a mounting plate fixedly connected to it.

[0023] Figure 6 The amplitude-frequency response curves are obtained from simulations of individual active damping components, passive damping components, and active and passive damping components connected in series.

[0024] Figure 7 This is a three-dimensional structural diagram of the spline drive shaft in this utility model.

[0025] Figure 8 This is a three-dimensional structural diagram of the cam in this utility model.

[0026] Figure 9 This is a simplified mechanical model diagram of this utility model.

[0027] The components include: 1. Main component; 101. Lower guide column; 102. Base plate; 200. Active damping component; 201. Lower guide column; 202. Oil tank; 202-1. Oil cavity; 202-2. Mounting groove; 203. Flange; 204. Piston block; 205. Return spring; 206. Driven rod; 207. Axial positioning nut; 208. Spline drive shaft; 208-1. Spline keyway; 209. Gasket; 210. Cam; 210-1. Internal spline key; 211. Drive motor; 212. Displacement sensor; 300. Passive damping component; 301. Hydraulic housing; 302. Passive piston; 303. Upper guide column; 304. Placement plate. Detailed Implementation

[0028] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0031] Example 1: Refer to Figures 1-6 This is the first embodiment of the present invention. This embodiment provides a hydraulic shock absorber that, when the base plate 102 is impacted, prevents the impact from being transmitted upward through the arrangement of the active shock absorber 200 and the passive shock absorber 300.

[0032] A hydraulic shock absorber includes a main body component 1, including a base plate 102, on which at least two lower guide columns 101 are fixed. In this embodiment, there are two lower guide columns 101 arranged diagonally. An active damping component 200 for actively reducing vibration is provided above the base plate 102.

[0033] Specifically, the active damping assembly 200 includes a displacement sensor 212 fixedly connected to the upper side of the base plate 102, an oil tank 202 with an oil cavity 202-1 slidably connected to the lower guide post 101, and at least one lower piston rod 201 fixedly connected to the upper side of the base plate 102. In this embodiment, two lower piston rods 201 are provided, arranged diagonally, and the upper end of the lower piston rod 201 can extend into the oil cavity 202-1. The lower end of the oil tank 202 has a sliding groove corresponding to several lower guide posts 101. The oil tank 202 is slidably connected to the corresponding lower guide post 101 through the sliding groove. An adjustment groove is provided on the oil tank 202 at the oil cavity 202-1. The oil tank 202 is slidably connected to the piston block 204 through the adjustment groove. A piston block 204 is fixedly connected to the outside of the oil tank 202. A flange 203 with a corresponding groove is connected to the inner side of the flange 203 and the outer side of the piston block 204. A return spring 205 is connected to the center of the oil tank 202. A spline drive shaft 208 is rotatably connected to the center of the oil tank 202. A driven rod 206 is fixedly connected to the inner end of the piston block 204. Several cams 210 corresponding to the driven rod 206 are connected to the spline drive shaft 208. The driven rod 206 is always in contact with the outer circumference of the cam 210 under the action of the return spring 205. The lower end of the oil tank 202 has a mounting groove 202-2. A drive motor 211 is fixedly connected to the oil tank 202 through the mounting groove 202-2. An output shaft is connected to the drive motor 211. The upper end of the output shaft extends into the oil chamber 202-1. The spline drive shaft 208 is fixedly connected to the output shaft extending into the oil chamber 202-1.

[0034] The return spring 205 is always in a compressed state; when the worktable is impacted, its upper surface will adapt to the vibration, the base plate 102 is impacted along with the worktable, the end of the lower piston rod 201 extending into the oil chamber 202-1 moves, the volume of the oil chamber 202-1 changes, and the displacement sensor 212 detects the displacement change of the upper surface of the worktable in real time. The displacement sensor 212 transmits displacement change signals to an external controller. The external controller controls the drive motor 211 to operate based on the received displacement change signals, causing the output shaft to rotate. The output shaft drives the cam 210 to rotate via the spline drive shaft 208. When the cam 210 rotates, the driven rod 206 moves accordingly. Taking the upward movement of the piston rod 201 as an example, and the reduction in the volume of the oil chamber 202-1 due to impact as an example, the direction of the drive motor 211 is controlled so that the cam 210 pushes the piston block 204 away from the spline drive shaft 208 via the driven rod 206. The squeezed oil quickly fills the enlarged chamber, restoring the volume of the oil chamber 202-1. The drive motor 211 stops operating, preventing the impact from being transmitted to the outside and reducing the vibration impact on the precision instrument.

[0035] Specifically, it also includes a passive damping component 300, which includes a hydraulic housing 301 disposed above the oil tank 202 and a passive piston 302 fixedly connected to the upper side of the oil tank 202. Several upper guide columns 303 are fixedly connected to the upper side of the oil tank 202. The hydraulic housing 301 is slidably connected to the several upper guide columns 303. The upper guide columns 303 are used to support the hydraulic housing 301. The upper part of the passive piston 302 is inside the hydraulic housing 301, and the center of the hydraulic housing 301 can slide up and down along the passive piston 302.

[0036] During implementation, a placement plate 304 for placing precision instruments is fixed above the hydraulic tank 301; the oil tank 202 and the hydraulic tank 301 contain oil and inert gas, and the oil tank 202 and the hydraulic tank 301 are respectively provided with oil or gas injection ports for convenient oil or gas injection (taking the injection of oil and inert gas into the oil tank 202 as an example, the steps for injecting oil and inert gas are as follows: first, pretreatment, cleaning, drying and leak testing of the hydraulic cylinder (to ensure a qualified seal), fixing it on a tiltable tooling table (for easy venting), with the oil or gas injection port facing upwards or tilted at 45 degrees). ° (Reduce gas-liquid mixing); Next, inject hydraulic oil, connect the oil inlet to the oil injection system with a check valve, and simultaneously evacuate the tank (vacuum degree ≥ -0.08MPa) through the auxiliary interface (or temporary pipe) on the tooling table to remove internal air. Start the oil injection system and inject hydraulic oil according to the preset volume (e.g., 40mL). During the oil injection process, keep the oil tank 202 tilted so that the oil naturally fills the bottom, and the air is drawn away from the vicinity of the oil inlet by vacuum (oil injection and vacuuming are carried out simultaneously). After the oil injection is completed, close the oil injection valve and disconnect the oil injection system. At this time, the oil inlet is not sealed. Finally, inert gas injection is performed. The connection is changed, and the oil inlet is connected to the gas filling machine, ensuring a tight seal. Inert gas is slowly injected into the preset volume (e.g., 20mL of standard nitrogen) through the filling machine (filling speed ≤5mL / s to avoid impacting the oil and generating air bubbles). During injection, the pressure inside the oil tank 202 is monitored by a pressure sensor (oil at the bottom, gas at the top) to calculate the actual gas volume (combined with temperature compensation) to ensure accurate measurement. After gas injection, a special sealing component (e.g., with a one-way valve) is immediately used. (Use the nut) to seal the oil inlet to prevent gas and liquid leakage. Perform a pressure test to confirm no leakage, and the operation is complete. The above is the basic operation of gas or oil injection in this field, and no accompanying drawings are required for explanation. After the impact is attenuated once by the active damping component 200, it is transmitted to the passive damping component 300, and the passive piston 302 moves upward, thereby squeezing the oil and transferring kinetic energy to the oil, which becomes the internal energy of the oil. At the same time, some energy is consumed, which has a certain damping effect, but this effect is negligible. This layer of shock absorber is theoretically basically the same as the traditional hydraulic shock absorber. The purpose of adding this layer is not to expect it to play an important role in low-frequency damping, but mainly to gradually cooperate with the active damping. Through reasonable configuration parameters, the natural frequencies of the active damping component 200 and the passive damping component 300 are different, avoiding the resonance area and improving the overall damping capacity of the shock absorber.

[0037] A simplified mechanical model is established based on the physical model (e.g., Figure 9 As shown in the figure, x represents the displacement of the lower piston rod 201 in the active damping assembly 200. Let x be the velocity of the lower piston rod 201. T To achieve the ideal displacement for the drive motor 211 to move the piston block 204, Let z be the ideal speed at which the drive motor 211 moves the piston block 204, and z be the displacement of the oil tank 202. Let y be the velocity of the lower piston rod 201, and y be the displacement of the hydraulic housing 301. The speed of the hydraulic housing 301 is given by , and w is the actual displacement of the piston block 204 driven by the drive motor 211. Let m1 be the actual speed at which the piston block 204 moves driven by the drive motor 211, A1 be the mass of the passive damping component 300, A1 be the cross-sectional area of ​​the passive piston 302, p1 be the pressure of the oil in the passive damping component 300, c1 be the damping coefficient of the passive damping component 300, m2 be the mass of the active damping component 200, A2 be the total cross-sectional area of ​​the lower piston rod 201, P2 be the pressure of the oil in the oil tank 202, and c2 be the damping coefficient of the active damping component 200. w For the total mass of piston block 204, A w C is the total cross-sectional area of ​​piston block 204. w k is the damping coefficient of piston block 204. w (Stiffness coefficient of the spring).

[0038] In Matlab Simulink, a simulation model is built, and simulation parameters are set, specifically: gas modulus. liquid modulus These two parameters are the same for both the active and passive layers, and the threshold we set to distinguish between high and low frequencies is... Other parameter settings for the passive damping component 300: initial volume of gas inside the hydraulic housing 301. Initial volume of liquid The cross-sectional area of ​​the passive piston 302 ,quality Damping coefficient Other parameter settings for the active damping component 200: initial gas volume Initial volume of liquid The cross-sectional area of ​​the lower piston rod 201 ,quality Damping coefficient The cross-sectional area of ​​the piston block 204 pushed by the drive motor 211 when it is activated. ,quality Damping coefficient Spring stiffness After setting the parameters, we input a sinusoidal excitation to the model and observe its attenuation effect. For example... Figure 6As shown in the amplitude-frequency characteristics, when the passive damping component 300 is used alone, its amplitude-frequency characteristic is greater than 1 in the resonance region. When the active damping component 200 is used alone, its amplitude-frequency characteristic is also greater than 1 in the resonance region. When the passive damping component 300 and the active damping component 200 are connected in series, their amplitude-frequency characteristic can be kept less than 1 in the entire frequency domain, thus achieving ultra-low frequency damping.

[0039] Example 2: Refer to Figure 3 , Figure 7 and Figure 8 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that it further facilitates the mounting of the cam 210 onto the spline drive shaft 208.

[0040] Specifically, a number of spline keyways 208-1 are arranged on the spline drive shaft 208, the number of spline keyways 208-1 being an integer multiple of the number of cams 210. A number of internal spline teeth 210-1 corresponding one-to-one with the spline keyways 208-1 are arranged on the inner side of the cams 210. The cams 210 are sleeved on the spline drive shaft 208, and the internal spline teeth 210-1 are inserted into the spline drive shaft 208 through the spline keyways 208-1. The lowermost cam 210 is attached to the shoulder of the spline drive shaft 208 below the spline keyways 208-1. Washers 209 are connected to the spline drive shaft 208 between adjacent cams 210. An axial positioning nut 207 is threaded to the upper end of the spline drive shaft 208, and the lower side of the axial positioning nut 207 is attached to the upper side of the uppermost cam 210. In this embodiment, the number of cams 210 is preferably 4.

[0041] After the cam 210 is installed on the spline drive shaft 208, the distance from the central axis of the spline drive shaft 208 to the contact point between each driven rod 206 and the outer side of the cam 210 needs to be the same. In the circumferential direction, the installation angle difference between two adjacent cams 210 is 90 degrees. In this embodiment, the setting of the spline keyway 208-1 and the inner spline key teeth 210-1 facilitates the positioning of the angle of each cam 210 on the spline drive shaft 208. It is only necessary to align the inner spline key teeth 210-1 on each cam 210 with the spline keyway 208-1 of the corresponding angle.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A hydraulic shock absorber, characterized in that: include, The main component includes a base plate, on which at least two lower guide posts are fixed; The active damping assembly includes a displacement sensor fixedly connected to the upper side of the base plate, an oil tank with an oil cavity slidably connected to the lower guide column, a sliding groove corresponding to several lower guide columns at the lower end of the oil tank facing downwards, the oil tank being slidably connected to the corresponding lower guide column via the sliding groove, an adjustment groove on the oil tank at the oil cavity, a piston block being slidably connected to the oil tank via the adjustment groove, a flange corresponding to each adjustment groove being fixedly connected to the outside of the oil tank, and a return spring connecting the inside of the flange and the outward side of the piston block.

2. The hydraulic shock absorber as described in claim 1, characterized in that: The center of the oil tank is rotatably connected to a splined drive shaft, and the inner end of the piston block is fixedly connected to a driven rod. Several cams corresponding one-to-one with the driven rods are connected to the splined drive shaft, and the driven rods are always in contact with the outer circumference of the cams under the action of the return spring.

3. The hydraulic shock absorber as described in claim 2, characterized in that: The oil tank has a mounting groove at the downward end, and a drive motor is fixedly connected to the oil tank through the mounting groove. An output shaft is connected to the drive motor, and the upper end of the output shaft extends into the oil chamber. A spline drive shaft is fixedly connected to the output shaft extending into the oil chamber.

4. The hydraulic shock absorber as described in any one of claims 1 to 3, characterized in that: It also includes a passive damping assembly, which includes a hydraulic tank located above the oil tank and a passive piston fixedly connected to the upper side of the oil tank. Several upper guide columns are fixedly connected to the upper side of the oil tank, and the hydraulic tank is slidably connected to the several upper guide columns. The upper part of the passive piston extends into the hydraulic tank, and the center of the hydraulic tank can slide up and down along the passive piston.

5. The hydraulic shock absorber as described in any one of claims 1 to 3, characterized in that: At least one lower piston rod is fixedly connected to the upper side of the base plate, and the upper end of the lower piston rod can extend into the oil chamber.

6. The hydraulic shock absorber as described in claim 2 or 3, characterized in that: The spline drive shaft has a number of spline keyways arranged on it. The number of spline keyways is an integer multiple of the number of cams. The inner side of the cam has a number of internal spline teeth that correspond one-to-one with the spline keyways. The cam is sleeved on the spline drive shaft. The internal spline teeth are inserted into the spline drive shaft through the spline keyways. The lowermost cam is attached to the shoulder of the spline drive shaft on the lower side of the spline keyway.

7. The hydraulic shock absorber as described in claim 6, characterized in that: Shims are connected to the splined drive shaft between adjacent cams.

8. The hydraulic shock absorber as described in claim 6, characterized in that: The number of cams is 4.

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