High-precision control air spring piston flow limiting mechanism

Abstract

The invention discloses a high-precision control gas spring piston flow limiting mechanism in the technical field of gas springs, and aims to solve the technical problems that an existing gas spring is low in damping adjustment precision and cannot be dynamically controlled. The mechanism comprises a main body, a hollow piston rod, a main piston, a rotary valve plate, an inner driving shaft and a micro stepping motor, the air cylinder is characterized in that a micro stepping motor is integrated in a connecting seat outside the piston rod, and a rotary valve plate on a main piston in the air cylinder is driven to rotate through an inner driving shaft penetrating through the hollow piston rod, so that the flow area of a throttling hole is accurately changed. The driving motor is externally arranged, a coaxial inner transmission structure is adopted, high-precision, quantifiable and dynamic real-time control over the damping force of the gas spring is achieved, and the device has the advantages of being compact in structure, high in intelligent degree, high in response speed and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas springs, in particular to a gas spring piston flow limiting mechanism capable of accurately controlling damping force. BACKGROUND

[0002] As a functional industrial accessory, gas springs are widely used in many fields such as automobiles, medical devices, furniture, and mechanical equipment due to their functions of support, cushioning, braking, height and angle adjustment, etc. The damping characteristics of traditional gas springs are usually fixed at the time of factory shipment, or only provide very limited adjustment capability.

[0003] In the prior art, some adjustable damping gas springs attempt to solve this problem, for example, the existing Chinese patent with publication number CN211820530U discloses a damping gas spring, which adjusts the pre-tightening force of the internal spring or changes the fixed opening of the throttle valve through a mechanical thread structure. However, the existing adjustment methods generally have the following defects:

[0004] 1. The manual mechanical adjustment method usually relies on the operator's sense of touch and experience, and the adjustment process is rough, which cannot achieve accurate and quantifiable setting of damping force, and it is also difficult to ensure consistency after adjustment of different batches or at different times.

[0005] 2. Indirectly affecting the damping force by adjusting the spring pre-tightening force and the like, the response speed is slow, which cannot meet the working conditions that require rapid change of damping.

[0006] Therefore, how to provide a gas spring mechanism capable of high-precision control of damping force has become a technical problem to be solved in the field. SUMMARY

[0007] The purpose of the present application is to provide a high-precision control gas spring piston flow limiting mechanism to solve the technical problems of low control precision, inability to quantitatively set, slow response speed, and inability to dynamically adjust in the working stroke in the damping adjustment of the existing gas spring.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solution: a high-precision control gas spring piston flow limiting mechanism, comprising:

[0009] a main body;

[0010] a piston rod in sliding connection with the main body, the piston rod being a hollow structure;

[0011] a main piston fixedly connected to one end of the piston rod, the main piston dividing the interior of the main body into a first chamber and a second chamber, and at least one fixed throttle hole being formed in the main piston;

[0012] A rotating valve plate is attached to the surface of the main piston, and a matching hole is formed in the rotating valve plate corresponding to the fixed throttle hole;

[0013] An inner drive shaft is arranged inside the hollow piston rod, and one end of the inner drive shaft is fixedly connected with the rotating valve plate;

[0014] A drive device is arranged outside the main body, and the drive device is a micro stepping motor, the output end of the micro stepping motor is in transmission connection with the other end of the inner drive shaft, and is used for driving the rotating valve plate to rotate, so as to change the overlapping area of the fixed throttle hole and the matching hole, thereby adjusting the flow rate of the gas between the first chamber and the second chamber.

[0015] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, the one end of the piston rod away from the main piston is fixedly connected with a U-shaped fork connecting seat, and the micro stepping motor is integrated and packaged in the groove of the U-shaped fork connecting seat.

[0016] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, the output end of the micro stepping motor is connected with the end of the inner drive shaft through a micro shaft coupling.

[0017] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, a self-lubricating bushing for reducing rotating friction is arranged between the central through hole of the main piston and the inner drive shaft.

[0018] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, the end of the inner drive shaft penetrating through the rotating valve plate is sequentially provided with a wave spring for providing axial pre-tightening force to tightly attach the rotating valve plate to the main piston, and a snap spring for preventing the rotating valve plate from being axially detached.

[0019] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, a limiting protrusion is arranged on the rotating valve plate, and a limiting groove matched with the limiting protrusion is arranged on the surface of the main piston, which is used for mechanically limiting the rotating range of the rotating valve plate.

[0020] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, a connecting groove is formed in the main piston, an extrusion spring is arranged in the connecting groove, one end of the extrusion spring is connected with a rubber block, and the rubber block is in elastic sealing contact with the inner wall of the main body under the action of the extrusion spring.

[0021] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, a gas-permeable hole is formed in the wall of the main body and communicates with the first chamber, and a filter plate for filtering air is detachably installed in the gas-permeable hole.

[0022] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, the filter plate is fixed in the gas-permeable hole by a limiting check ring, and a pull handle is connected to the filter plate for facilitating pulling and replacement.

[0023] As a preferred scheme of the high-precision control gas spring piston flow limiting mechanism, a controller is further included for sending control instructions to the micro stepping motor to accurately control the angle and speed of rotation of the motor.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] 1. The external controller sends digital pulse signals to the micro stepping motor, and the motor accurately drives the rotary valve plate to rotate a specific angle through the inner drive shaft, thereby changing the overlapping area of the matching hole and the fixed orifice. Since the stepping angle of the motor is known, the opening of the orifice can be accurately calculated and quantified, thereby achieving accurate setting of the damping force and completely overcoming the defects of the prior art that rely on feel and cannot be quantified.

[0026] 2. The micro stepping motor is integrated and packaged inside the U-shaped fork connecting seat that moves together with the piston rod, and coaxial transmission is achieved by using an inner drive shaft that penetrates the hollow piston rod. Without increasing the redundant structure outside the gas spring, the problem of applying rotary drive to a linear reciprocating component is perfectly solved, making the overall structure extremely compact and the transmission reliable.

[0027] 3. Since the driving source is a micro stepping motor with extremely fast response speed, the mechanism can change the opening of the orifice at any time according to external instructions during a single working stroke of the gas spring. For example, the system can increase the opening (low damping) when fast movement is needed and decrease the opening (high damping) when buffer braking is needed according to the movement speed of the piston rod. This ability to adjust the damping in real time during work is completely impossible with traditional static adjustment methods, making the present application easy to integrate into an automated control system.

[0028] 4. By setting the combination of wave springs and clips, a continuous axial pre-tightening force is applied to the rotary valve plate to ensure that it tightly fits the main piston even under high-pressure gas impact, effectively preventing internal leakage; by setting the mechanical limiting of the limiting protrusion and the limiting groove, the problem of motor overload or damage to the internal valve plate mechanism due to control errors is prevented. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings. Among them:

[0030] Figure 1 The overall structure inside the high-precision control gas spring piston flow limiting mechanism of the present application is shown schematically.

[0031] Figure 2 The high-precision control gas spring piston flow limiting mechanism of the present application is shown schematically. Figure 1 The enlarged view of A is shown.

[0032] Figure 3 The high-precision control gas spring piston flow limiting mechanism of the present application is shown schematically. Figure 1 The enlarged view of B is shown.

[0033] Figure 4 The high-precision control gas spring piston flow limiting mechanism of the present application is shown schematically. Figure 1 The enlarged view of C is shown.

[0034] Figure 5 The fixed throttling hole and the matching hole of the high-precision control gas spring piston flow limiting mechanism of the present application are shown schematically.

[0035] Figure 6 The fixed throttling hole and the matching hole of the high-precision control gas spring piston flow limiting mechanism of the present application are shown schematically.

[0036] Figure 7 The fixed throttling hole and the matching hole of the high-precision control gas spring piston flow limiting mechanism of the present application are shown schematically.

[0037] Figure 8 The fixed throttling hole and the matching hole of the high-precision control gas spring piston flow limiting mechanism of the present application are shown schematically.

[0038] In the figure: 1, main body; 2, piston rod; 3, U-shaped yoke connecting seat; 4, main piston; 5, rotary valve plate; 6, groove; 7, inner drive shaft; 8, micro stepping motor; 9, self-lubricating shaft sleeve; 10, fixed throttling hole; 11, matching hole; 12, snap spring; 13, wave spring; 14, limiting groove; 15, limiting protrusion; 16, first chamber; 17, second chamber; 101, air hole; 102, limiting check ring; 103, filter plate; 104, pull handle; 401, connecting groove; 402, rubber block; 403, extrusion spring. DETAILED DESCRIPTION

[0039] In order to make the above objectives, characteristics and advantages of the present application more obvious and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0040] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details given herein, that the present application can be practiced with other elements in addition to or in place of those listed, and that the present application can be practiced without limitations on the order of the steps. Thus, the specific embodiments given herein are by way of example only and the scope of the present application is not limited by the specific details given herein.

[0041] Secondly, the term "one embodiment" or "an embodiment" as used herein means that a particular implementation can include a particular feature, structure, or characteristic, but every embodiment can not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, embodiments can be combined in any way.

[0042] Thirdly, the present application is described in detail with reference to the accompanying drawings. In the detailed description of the embodiments of the present application, the sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the accompanying drawings are only examples, which should not limit the scope of protection of the present application. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in the actual manufacture.

[0043] Embodiment 1

[0044] Please refer to Figures 1-8 For the first embodiment of the present application, a high-precision control gas spring piston flow limiting mechanism is provided, which comprises:

[0045] A main body 1 is formed with a closed cylinder inside. A hollow piston rod 2 passes through the end cover of the main body 1 and can slide therein. The end of the piston rod 2 inside the main body 1 is firmly connected to a main piston 4. The main piston 4 divides the inside of the main body 1 into a first chamber 16 and a second chamber 17.

[0046] At least one fixed orifice 10 is uniformly provided on the main piston 4. A disc-shaped rotary valve plate 5 is tightly attached to the surface of the main piston 4, and the rotary valve plate 5 is also provided with matching holes 11 corresponding in position and shape to the fixed orifice 10. An elongated inner drive shaft 7 is provided inside the hollow piston rod 2, and one end of the inner drive shaft 7 passes through the center of the main piston 4 and is fixedly connected with the rotary valve plate 5. When the inner drive shaft 7 rotates, it drives the rotary valve plate 5 to rotate relative to the main piston 4, thereby changing the overlapping area of the matching holes 11 and the fixed orifice 10, and adjusting the gas flow cross section.

[0047] At the end of the piston rod 2 away from the main piston 4, a U-shaped yoke connecting seat 3 is fixedly connected for connecting with external load. The micro stepping motor 8 of the embodiment is integrated and packaged in the groove 6 inside the U-shaped yoke connecting seat 3, the other end of the inner drive shaft 7 extends into the U-shaped yoke connecting seat 3, and is in transmission connection with the output shaft of the micro stepping motor 8 through a micro coupling. An external controller sends a control instruction to the micro stepping motor 8 through a flexible cable to drive it to rotate accurately, so as to realize remote and accurate control of the internal rotary valve disc 5.

[0048] In order to ensure the stability and low friction of the rotation of the inner drive shaft 7, a self-lubricating bushing 9 is arranged between the central through hole of the main piston 4 and the inner drive shaft 7.

[0049] In order to ensure that the rotary valve disc 5 is always tightly attached to the surface of the main piston 4 to prevent gas from leaking from the attachment surface, a wave spring 13 for pre-tightening and a circlip 12 for axial positioning are sequentially sleeved at the end of the inner drive shaft 7.

[0050] In order to prevent the motor from being overloaded or damaged by misoperation, a limiting protrusion 15 is arranged on the rotary valve disc 5, and a limiting groove 14 is arranged at the corresponding position on the surface of the main piston 4, which constitutes a mechanical limiting to limit the maximum rotation range of the rotary valve disc 5.

[0051] In order to compensate for the long-term wear of the piston seal, a connecting groove 401 is formed on the main piston 4, in which an extrusion spring 403 continuously pushes a rubber block 402, so that the rubber block 402 is always in good elastic sealing contact with the inner wall of the main body 1.

[0052] In order to prevent dust from entering the cylinder, a gas permeable hole 101 is formed on the wall of the main body 1, and a filter plate 103 is detachably installed in the gas permeable hole 101 through a limiting baffle 102. The pull handle 104 on the filter plate 103 facilitates the user to clean or replace it regularly.

[0053] During use, when it is necessary to adjust the damping force of the gas spring, the external controller sends an accurate angle control instruction to the micro stepping motor 8 integrated in the U-shaped yoke connecting seat 3. After receiving the instruction, the motor rotates to drive the inner drive shaft 7 to rotate synchronously through the micro coupling. The inner drive shaft 7 in turn drives the rotary valve disc 5 on the main piston 4 to rotate. This rotation changes the coincidence degree of the matching hole 11 and the fixed throttling hole 10, that is, changes the throttling area of the gas flowing between the first chamber 16 and the second chamber 17. The larger the throttling area, the smaller the damping force; the smaller the throttling area, the larger the damping force. Since the whole process is accurately controlled by an electrical signal, high-precision adjustment of the damping force can be realized.

[0054] Embodiment 2

[0055] The embodiment is similar to the first embodiment in most of the structure, and the main difference is the specific form of the flow limiting mechanism.

[0056] In this embodiment, the flow limiting mechanism no longer uses the rotating valve plate 5, but uses a translational slide valve structure. Specifically, the fixed throttle hole 10 on the main piston 4 can be long strip-shaped or rectangular. Instead of the rotating valve plate 5 is a slider that can make linear translational motion on the surface of the main piston 4. The end of the inner drive shaft 7 is machined with a precision thread, which constitutes a screw-nut pair with the internal threaded hole on the slider. When the micro stepping motor 8 drives the inner drive shaft 7 to rotate, the slider will linearly displace under the action of the screw thread, thereby linearly changing the blocking area of the fixed throttle hole 10, and also can realize accurate control of the gas flow cross section. This scheme has advantages in some occasions that require pure linear control characteristics.

[0057] Embodiment 3

[0058] The mechanical structure of this embodiment is basically the same as that of the first embodiment, and the main difference is the selection of the elements for driving and feedback control to realize more advanced closed-loop control.

[0059] In this embodiment, the driving device uses a micro servo motor with an encoder to replace the micro stepping motor 8 in the first embodiment. The servo motor can feed back the position information of itself to the controller in real time, thereby forming a complete closed-loop control system, which can eliminate the out-of-step error that may exist in the stepping motor, making the angle control more reliable and accurate.

[0060] In addition, in order to realize automatic calibration and zero point calibration of the system, the mechanical limiting structure is cancelled in this embodiment and replaced by electronic limiting. Specifically, a micro permanent magnet is installed at a specific position of the rotating valve plate 5, such as the full-closed position, and a Hall effect sensor is fixed at the corresponding position of the main piston 4. Each time the system is powered on, the controller can drive the motor to rotate the valve plate until the Hall sensor detects the magnetic field signal, and the controller finds the 0 scale of the valve plate position. After that, all accurate angle controls can be calculated from this starting point.

[0061] Embodiment 4

[0062] The mechanical structure of this embodiment is basically the same as that of the first embodiment, and the main difference is the piston sealing structure.

[0063] In this embodiment, the self-compensating elastic sealing structure composed of the connecting groove 401, the rubber block 402 and the extruded spring 403 in Embodiment One is cancelled. Instead, one or more standard sealing grooves are opened on the outer circumference of the main piston 4, and a general O-shaped sealing ring or U-shaped piston sealing ring is installed in the groove. Although this structure does not have the self-compensation function of wear, it is simple in design, low in manufacturing cost, high in standardization of parts, and convenient to replace, and is an extremely cost-effective choice in many application scenarios where the life requirement is not extremely harsh.

[0064] The technical solutions of the present application are described in detail through the four embodiments above. These embodiments can be combined with each other, for example, the translation slide valve structure of Embodiment Two can also be combined with the servo motor and Hall sensor of Embodiment Three. Any equivalent replacement or deformation made by using the core idea of the present application, i.e. the design of driving the inner drive shaft penetrating the hollow piston rod by the motor integrated on the outside of the piston rod, and then controlling the opening degree of the flow limiting valve inside the cylinder, should fall within the protection scope of the present application.

Claims

1. A high-precision control gas spring piston flow limiting mechanism, characterized in that, include: Main body (1); A piston rod (2) is slidably connected to the main body (1), and the piston rod (2) is a hollow structure; A main piston (4) is fixedly connected to one end of the piston rod (2). The main piston (4) divides the interior of the main body (1) into a first chamber (16) and a second chamber (17). At least one fixed throttling hole (10) is provided on the main piston (4). A rotary valve plate (5) is attached to the surface of the main piston (4), and a matching hole (11) corresponding to the fixed throttling hole (10) is provided on the rotary valve plate (5). An inner drive shaft (7) is inserted inside the hollow piston rod (2), and one end of the inner drive shaft (7) is fixedly connected to the rotary valve plate (5); And a drive device disposed outside the main body (1), the drive device being a micro stepper motor (8), the output end of the micro stepper motor (8) being connected to the other end of the inner drive shaft (7) for driving the rotary valve plate (5) to rotate, thereby changing the overlapping area of ​​the fixed throttling orifice (10) and the matching orifice (11), thereby adjusting the flow rate of gas between the first chamber (16) and the second chamber (17).

2. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: The piston rod (2) is fixedly connected to a U-shaped fork connector (3) at one end away from the main piston (4), and the micro stepper motor (8) is integrated and encapsulated in the groove (6) of the U-shaped fork connector (3).

3. The high-precision control gas spring piston flow limiting mechanism according to claim 2, characterized in that: The output end of the micro stepper motor (8) is connected to the end of the inner drive shaft (7) via a micro coupling.

4. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: A self-lubricating bushing (9) for reducing rotational friction is provided between the central through hole of the main piston (4) and the inner drive shaft (7).

5. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: The inner drive shaft (7) passes through the end of the rotary valve plate (5) and is sequentially provided with a wave spring (13) for providing axial preload to make the rotary valve plate (5) fit tightly against the main piston (4), and a retaining ring (12) for preventing the rotary valve plate (5) from axially falling off.

6. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: The rotary valve plate (5) is provided with a limiting protrusion (15), and the surface of the main piston (4) is provided with a limiting groove (14) that cooperates with the limiting protrusion (15) to mechanically limit the rotation range of the rotary valve plate (5).

7. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: The main piston (4) is provided with a connecting groove (401), and a compression spring (403) is provided in the connecting groove (401). One end of the compression spring (403) is connected to a rubber block (402). Under the action of the compression spring (403), the rubber block (402) forms an elastic sealing contact with the inner wall of the main body (1).

8. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: The main body (1) has an air vent (101) that communicates with the first chamber (16) on its wall. A filter plate (103) for filtering air is detachably installed in the air vent (101).

9. The high-precision control gas spring piston flow limiting mechanism according to claim 8, characterized in that: The filter plate (103) is fixed inside the vent (101) by a limiting ring (102), and a pull handle (104) is connected to the filter plate (103) for easy pulling and replacement.

10. The high-precision control gas spring piston flow limiting mechanism according to claim 1, characterized in that: It also includes a controller for sending control commands to the micro stepper motor (8) to precisely control its rotation angle and speed.

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