A low-frequency variable-resonance electro-hydraulic vibration cylinder and its method for stepless change of resonance frequency

Abstract

The present invention relates to the technical field of electro-hydraulic excitation, and specifically discloses a low-frequency variable-resonance electro-hydraulic excitation cylinder and a method for continuously varying the resonance frequency thereof, including an outer cylinder body, an internally-mounted hydraulic check valve, an inner cylinder body, a flow channel, a conical helical spring, a buffer spring, an inner piston, a piston rod, and an exhaust hole. Aiming at problems such as the difficulty in utilizing the resonance energy of traditional electro-hydraulic excitation cylinders and the difficulty in adjusting the resonance frequency, the present invention utilizes the variability of the stiffness of the conical helical spring, and continuously adjusts the natural frequency of the excitation cylinder system by continuously adjusting the stiffness of the conical helical spring, so that the excitation cylinder generates resonance in the low-frequency working section, improves the vibration output amplitude or load, and effectively improves the working efficiency of the electro-hydraulic excitation cylinder.

Description

Technical Field

[0001] The present invention relates to the technical field of electro-hydraulic excitation, and particularly to a low-frequency variable resonance electro-hydraulic excitation cylinder and a method for continuously variable resonance frequency thereof. Background Technique

[0002] With the development of modern industrial technology level, especially to meet the needs of vibration environment simulation experiments of many construction machinery, higher requirements are put forward for the working frequency range, vibration output load and amplitude, and controllability of electro-hydraulic exciters. The electro-hydraulic excitation cylinder is an actuator of the electro-hydraulic excitation system, and is a device driven by electro-hydraulic principle to generate corresponding vibrations. The resonance of the electro-hydraulic excitation cylinder occurs when the electro-hydraulic excitation frequency is the same as or close to the natural frequency of the excitation cylinder system, and the vibration output amplitude or load increases.

[0003] In the low-frequency working section of the electro-hydraulic excitation cylinder, there is a problem that when the excitation frequency increases, the amplitude of the output load decays sharply. The natural frequency of the traditional electro-hydraulic excitation cylinder is the result of the interaction between the load mass and the hydraulic spring formed by the oil compressibility in the working chamber of the hydraulic cylinder. Therefore, its resonance generally occurs in the high-frequency section, and the resonance of the traditional electro-hydraulic excitation cylinder will generate a large shock wave pressure, which will damage the equipment sealing device and affect the stability and safety of the excitation system. Therefore, it is difficult to utilize the resonance energy at the resonance point to increase the vibration output amplitude or load. Moreover, the resonance frequency of the traditional electro-hydraulic excitation cylinder is generally difficult to adjust, so that the working efficiency of the electro-hydraulic excitation cylinder is greatly affected by the excitation frequency. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background technique, the purpose of the present invention is to provide a low-frequency variable resonance electro-hydraulic excitation cylinder and a method for continuously variable resonance frequency thereof, so that within the low-frequency range, the excitation cylinder can freely adjust the natural frequency of the system to be the same as the excitation frequency, achieving the purpose of increasing the vibration output load or amplitude.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A low-frequency variable resonance electro-hydraulic excitation cylinder includes an outer cylinder body, an internal hydraulic control check valve, an inner cylinder body, a flow channel, a conical spiral spring, a buffer spring, an inner piston, a piston rod, and an exhaust hole.

[0007] The inner cylinder body can reciprocate inside the outer cylinder body under the action of hydraulic oil, and the two form a first-stage left chamber and a first-stage right chamber; the piston rod can reciprocate inside the inner cylinder body under the action of hydraulic oil, and the two form a second-stage left chamber and a second-stage right chamber; a conical spiral spring is provided in the second-stage left chamber, and the left and right ends of the conical spiral spring are respectively fixedly connected to the inner cylinder body and the piston rod; an inner piston is provided in the second-stage right chamber, and the inner piston divides the second-stage right chamber into a buffer chamber and a pressure oil chamber. The inner piston can reciprocate inside the inner cylinder body under the action of hydraulic oil. A buffer spring is provided in the buffer chamber, and the left and right ends of the buffer spring are respectively fixedly connected to the piston rod and the inner piston; there is no hydraulic oil in the second-stage left chamber and the buffer chamber, and they are communicated with the outside air through exhaust holes.

[0008] The built-in hydraulic control one-way valve controls the unidirectional flow of hydraulic oil from the first-stage left chamber to the pressure oil chamber, and the control oil circuit of the hydraulic control one-way valve is communicated with the first-stage right chamber.

[0009] A method for steplessly changing the resonance frequency of a low-frequency variable resonance electro-hydraulic vibration cylinder, whose hydraulic control system includes an electro-hydraulic vibration valve, a first throttle valve, a second throttle valve, a third throttle valve, an oil tank, a relief valve, and a hydraulic source.

[0010] When the variable resonance electro-hydraulic vibration cylinder works, under the action of the electro-hydraulic vibration valve, the first-stage left and right chambers of the variable resonance electro-hydraulic vibration cylinder are alternately communicated with the hydraulic source and the oil tank, so that the inner cylinder body reciprocates; the pressure in the pressure oil chamber is higher than the pressures in the first-stage left chamber and the first-stage right chamber, and the built-in hydraulic control one-way valve is closed, and the pressure oil chamber is in a locked state. The piston rod reciprocates under the drive of the inner cylinder body and the action of the conical spiral spring and the buffer spring, and outputs an excitation waveform; compared with the compressibility of the mechanical spring, the compressibility of the oil can be ignored. The natural frequency of the variable resonance electro-hydraulic vibration cylinder is mainly related to the stiffness of the conical spiral spring and the buffer spring, and its natural frequency is relatively low. At this time, if the excitation frequency is the same as or close to the natural frequency of the variable resonance electro-hydraulic vibration cylinder system, resonance will occur, and the vibration output amplitude or load will increase significantly.

[0011] Adjustment of the natural frequency of the variable resonance electro-hydraulic vibration cylinder system: When the variable resonance electro-hydraulic vibration cylinder is unloaded, the electro-hydraulic vibration valve is in the middle position, the vibration cylinder is in the locked state, the first throttle valve is opened, the second and third throttle valves are closed, and the pressure of the relief valve is adjusted to be higher than the pressure in the pressure oil chamber. Under the action of the built-in hydraulic control one-way valve, hydraulic oil enters the pressure oil chamber, the inner piston moves to the left, and under the push of the buffer spring, the piston rod moves to the left, compressing the conical spiral spring until the large coil of the conical spiral spring begins to coil together, and the stiffness of the conical spiral spring continuously increases until it is completely tightened, thereby continuously increasing the natural frequency of the variable resonance vibration cylinder, and resonance can occur at different excitation frequencies, achieving the purpose of steplessly adjusting the stiffness of the conical spiral spring and thus steplessly adjusting the resonance frequency of the vibration cylinder;

[0012] When the electro-hydraulic excitation valve is in the middle position, the excitation cylinder is in the locked state. Close the first throttle valve, open the second and third throttle valves, and adjust the pressure of the overflow valve so that it is higher than the pressure of the pressure oil chamber. The high-pressure oil acts on the control oil circuit of the built-in hydraulic check valve through the first-stage right chamber. The hydraulic check valve opens, and the pressure oil chamber is connected to the oil tank through the first-stage left chamber, the second throttle valve to relieve pressure. The conical spiral spring resets and returns to the initial state.

[0013] Advantages of the present invention:

[0014] (1) The low-frequency variable resonance electro-hydraulic excitation cylinder of the present invention has a relatively low natural frequency of the excitation cylinder under the action of the conical spiral spring and the buffer spring. At this time, the natural frequency of the excitation cylinder is related to the stiffness of the conical spiral spring and the buffer spring, and has nothing to do with the compressibility of the oil. It will not generate a large shock wave pressure, thus affecting the stability and safety of the excitation system. The resonance energy can be fully and reasonably utilized in the low-frequency band. Compared with the traditional electro-hydraulic excitation cylinder, the stepless variable resonance electro-hydraulic excitation cylinder can output a larger amplitude or vibration load at the same excitation frequency and hydraulic source.

[0015] (2) The present invention provides a method for continuously varying the resonance frequency of a low-frequency variable resonance electro-hydraulic excitation cylinder. The stepless variable resonance electro-hydraulic excitation cylinder changes the natural vibration frequency of the excitation cylinder system by changing the stiffness of the conical spiral spring. It can continuously adjust the natural frequency of the excitation cylinder system by continuously adjusting the stiffness of the conical spiral spring, so that the excitation cylinder can adjust its own system natural frequency to be consistent with the required excitation frequency in the low-frequency working section, generate resonance, increase the vibration output amplitude or load, and effectively improve the working efficiency of the electro-hydraulic excitation cylinder. Description of the drawings

[0016] The present invention will be further described below with reference to the drawings.

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the working principle of the present invention.

[0019] In the figure: 1 - outer cylinder body, 101 - first-stage left chamber, 102 - first-stage right chamber, 2 - built-in hydraulic check valve, 3 - inner cylinder body, 31 - second-stage left chamber, 32 - buffer chamber, 33 - pressure oil chamber, 4 - flow channel, 5 - conical spiral spring, 6 - buffer spring, 7 - inner piston, 8 - piston rod, 9 - exhaust hole, 10 - first throttle valve, 11 - second throttle valve, 12 - third throttle valve, 13 - electro-hydraulic excitation valve, 14 - oil tank, 15 - overflow valve, 16 - external load. Detailed implementation manners

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] As Figure 1 shown, a low-frequency variable-resonance electro-hydraulic vibration cylinder includes an outer cylinder body 1, an internal pilot-operated check valve 2, an inner cylinder body 3, a flow channel 4, a truncated-cone spiral spring 5, a buffer spring 6, an inner piston 7, a piston rod 8, and an exhaust hole 9.

[0022] The inner cylinder body 3 can reciprocate inside the outer cylinder body 1 under the action of hydraulic oil, and the two form a first-stage left chamber 101 and a first-stage right chamber 102; the piston rod 8 can reciprocate inside the inner cylinder body 3 under the action of hydraulic oil, and the two form a second-stage left chamber 31 and a second-stage right chamber; a truncated-cone spiral spring 5 is provided in the second-stage left chamber 31, and the left and right ends of the truncated-cone spiral spring 5 are respectively fixedly connected to the inner cylinder body 3 and the piston rod 8; an inner piston 7 is provided in the second-stage right chamber, and the inner piston 7 divides the second-stage right chamber into a buffer chamber 32 and a pressure oil chamber 33. The inner piston 7 can reciprocate inside the inner cylinder body 3 under the action of hydraulic oil. A buffer spring 6 is provided in the buffer chamber 32, and the left and right ends of the buffer spring 6 are respectively fixedly connected to the piston rod 8 and the inner piston 7; there is no hydraulic oil in the second-stage left chamber 31 and the buffer chamber 32, and they are communicated with the outside air through the exhaust hole 9.

[0023] The internal pilot-operated check valve 2 controls the one-way flow of hydraulic oil from the first-stage left chamber 101 to the pressure oil chamber 33, and the control oil circuit of the pilot-operated check valve 2 is communicated with the first-stage right chamber 102.

[0024] As Figure 2 shown, a method for steplessly changing the resonance frequency of a low-frequency variable-resonance electro-hydraulic vibration cylinder, and its hydraulic control system includes an electro-hydraulic vibration valve 13, a first throttle valve 10, a second throttle valve 11, a third throttle valve 12, an oil tank 14, a relief valve 15, and a hydraulic source.

[0025] When the variable resonance electro-hydraulic vibration excitation cylinder works, under the action of the electro-hydraulic vibration excitation valve 13, the first-stage left chamber 101 and the first-stage right chamber 102 of the variable resonance electro-hydraulic vibration excitation cylinder are alternately connected to the hydraulic source and the oil tank, causing the inner cylinder body 3 to move reciprocally; the pressure in the pressure oil chamber 33 is higher than that in the first-stage left chamber 101 and the first-stage right chamber 102, the built-in hydraulic control check valve 2 is closed, and the pressure oil chamber 33 is in a locked state. The piston rod 8 moves reciprocally under the drive of the inner cylinder body 3 and the action of the conical spiral spring 5 and the buffer spring 6, outputting an excitation waveform; compared with the compressibility of the mechanical spring, the compressibility of the oil can be ignored. Therefore, the natural frequency of the variable resonance electro-hydraulic vibration excitation cylinder is mainly related to the stiffness of the conical spiral spring 5 and the buffer spring 6, and its natural frequency is relatively low. At this time, if the excitation frequency is the same as or close to the natural frequency of the variable resonance vibration excitation cylinder, resonance will occur, and the vibration output amplitude or load will increase significantly.

[0026] Adjustment of the natural frequency of the variable resonance electro-hydraulic vibration excitation cylinder system: When the variable resonance electro-hydraulic vibration excitation cylinder is unloaded, the electro-hydraulic vibration excitation valve 13 is in the middle position, the vibration excitation cylinder is in the locked state, the first throttle valve 10 is opened, the second throttle valve 11 and the third throttle valve 12 are closed, and the pressure of the relief valve 15 is adjusted to be higher than the pressure in the pressure oil chamber 33. Under the action of the built-in hydraulic control check valve 2, the hydraulic oil enters the pressure oil chamber 33, the inner piston 7 moves to the left, and under the push of the buffer spring 6, the piston rod 8 moves to the left, compressing the conical spiral spring 5 until the large coils of the conical spiral spring 5 start to coil together, and the stiffness of the conical spiral spring 5 continuously increases until it is completely tightened, thereby continuously increasing the natural frequency of the variable resonance vibration excitation cylinder, enabling resonance to occur at different excitation frequencies, and achieving the purpose of steplessly adjusting the stiffness of the conical spiral spring 5 and thus steplessly adjusting the resonance frequency of the vibration excitation cylinder;

[0027] When the electro-hydraulic vibration excitation valve 13 is in the middle position and the vibration excitation cylinder is in the locked state, the first throttle valve 10 is closed, the second throttle valve 11 and the third throttle valve 12 are opened, the pressure of the relief valve 15 is adjusted to be higher than the pressure in the pressure oil chamber 33, the high-pressure oil acts on the control oil circuit of the built-in hydraulic control check valve 2 through the first-stage right chamber 102, the hydraulic control check valve 2 is opened, and the pressure oil chamber is connected to the oil tank 14 through the first-stage left chamber 101, the second throttle valve 11 for pressure relief, and the conical spiral spring 5 returns to its initial state.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A low-frequency variable-resonance electro-hydraulic vibration cylinder, characterized in that, The variable-resonance electro-hydraulic vibration exciter cylinder includes an outer cylinder body (1), an internal hydraulic control check valve (2), an inner cylinder body (3), a flow channel (4), a truncated cone spiral spring (5), a buffer spring (6), an inner piston (7), a piston rod (8), and an exhaust hole (9); The inner cylinder body (3) can reciprocate inside the outer cylinder body (1) under the action of hydraulic oil, and the two form a first-stage left chamber (101) and a first-stage right chamber (102); the piston rod (8) can reciprocate inside the inner cylinder body (3) under the action of hydraulic oil, and the two form a second-stage left chamber (31) and a second-stage right chamber; the second-stage left chamber (31) is provided with a truncated cone spiral spring (5), and the left and right ends of the truncated cone spiral spring (5) are respectively fixedly connected to the inner cylinder body (3) and the piston rod (8); the second-stage right chamber is provided with an inner piston (7), and the inner piston (7) divides the second-stage right chamber into a buffer chamber (32) and a pressure oil chamber (33). The inner piston (7) can reciprocate inside the inner cylinder body (3) under the action of hydraulic oil. The buffer chamber (32) is provided with a buffer spring (6), and the left and right ends of the buffer spring (6) are respectively fixedly connected to the piston rod (8) and the inner piston (7); there is no hydraulic oil in the second-stage left chamber (31) and the buffer chamber (32), and they are communicated with the outside air through the exhaust hole (9); The internal hydraulic control check valve (2) controls the unidirectional flow of hydraulic oil from the first-stage left chamber (101) to the pressure oil chamber (33), and the control oil circuit of the hydraulic control check valve (2) is communicated with the first-stage right chamber (102).

2. The low-frequency variable resonance electro-hydraulic vibration cylinder according to claim 1, characterized in that, The hydraulic control system includes an electro-hydraulic vibration exciter valve (13), a first throttle valve (10), a second throttle valve (11), a third throttle valve (12), an oil tank (14), a relief valve (15), and a hydraulic source; When the variable-resonance electro-hydraulic vibration exciter cylinder works, under the action of the electro-hydraulic vibration exciter valve (13), the first-stage left chamber (101) and the first-stage right chamber (102) of the variable-resonance electro-hydraulic vibration exciter cylinder are alternately communicated with the hydraulic source and the oil tank, so that the inner cylinder body (3) reciprocates; the pressure in the pressure oil chamber (33) is higher than the pressures in the first-stage left chamber (101) and the first-stage right chamber (102), and the internal hydraulic control check valve (2) is closed, and the pressure oil chamber (33) is in a locked state. The piston rod (8) reciprocates under the drive of the inner cylinder body (3) and the action of the truncated cone spiral spring (5) and the buffer spring (6), and outputs an excitation waveform; at this time, if the excitation frequency is the same as or close to the natural frequency of the variable-resonance vibration exciter cylinder, resonance will occur, and the vibration output amplitude or load will increase significantly.

3. A method for steplessly varying the resonance frequency of a low-frequency variable resonance electro-hydraulic vibration cylinder as claimed in claim 1, characterized in that, When the variable resonance electro-hydraulic excitation cylinder is unloaded, the electro-hydraulic excitation valve (13) is in the middle position, the excitation cylinder is in the locked state. Open the first throttle valve (10), close the second throttle valve (11) and the third throttle valve (12), and adjust the pressure of the overflow valve (15) to be higher than the pressure of the pressure oil chamber (33). Under the action of the built-in hydraulic control check valve (2), the hydraulic oil enters the pressure oil chamber (33), the inner piston (7) moves to the left, and under the push of the buffer spring (6), the piston rod (8) moves to the left, compressing the truncated cone spiral spring (5) until the large coil of the truncated cone spiral spring (5) starts to undergo the phenomenon of coil merging. The stiffness of the truncated cone spiral spring (5) continuously increases until it is completely tightened, thereby continuously increasing the natural frequency of the variable resonance excitation cylinder, enabling resonance to occur at different excitation frequencies, and achieving the purpose of steplessly adjusting the stiffness of the truncated cone spiral spring (5) and thus steplessly adjusting the resonance frequency of the excitation cylinder; When the electro-hydraulic excitation valve (13) is in the middle position and the excitation cylinder is in the locked state, close the first throttle valve (10), open the second throttle valve (11) and the third throttle valve (12), and adjust the pressure of the overflow valve (15) to be higher than the pressure of the pressure oil chamber (33). The high-pressure oil acts on the control oil circuit of the built-in hydraulic control check valve (2) through the first-stage right chamber (102). The hydraulic control check valve (2) opens, and the pressure oil chamber is connected to the oil tank (14) through the first-stage left chamber (101), the second throttle valve (11) for pressure relief. The truncated cone spiral spring (5) resets to its initial state.

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