A π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve

Abstract

This invention provides a π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve, comprising a connecting housing, with an electro-mechanical converter and a valve body respectively connected to its two sides. An independent wet operating chamber and a dry operating chamber are arranged side-by-side within the connecting housing. A primary torque amplification mechanism is disposed in the dry operating chamber, and a secondary torque amplification mechanism is disposed in the wet operating chamber. The primary and secondary torque amplification mechanisms are connected. The secondary torque amplification mechanism includes a valve core lever and a π-axis, with the valve core lever movably connected to the π-axis at its lower end. The π-axis is integrally formed. Compared to existing technologies, the transmission mechanism of this invention eliminates complex machining steps such as grinding, making it easier to manufacture and applicable to industrial production.

Description

Technical Field

[0001] This invention relates to the field of electro-hydraulic servo valve technology, and more specifically to a π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve. Background Technology

[0002] An electro-hydraulic control system is a feedback control system that uses hydraulic power components as drive devices. In this system, output quantities such as displacement and force can quickly and accurately reproduce the changes in input quantities. The electro-hydraulic servo valve is the core of the electro-hydraulic control system. The input electrical signal acts on the electro-hydraulic servo valve, converting it into a high-power flow or pressure signal output. From this perspective, the electro-hydraulic servo valve is not only a signal receiving element, but also a power amplification element, and a control and execution element. The electro-hydraulic servo valve is the core component of the electro-hydraulic servo system, and its performance directly determines whether the servo system's functions and related characteristics can be realized.

[0003] Current two-dimensional electro-hydraulic servo valves generally use an electro-mechanical converter to drive a transmission mechanism. The transmission mechanism amplifies the torque of the electro-mechanical converter's rotation and transmits it to the valve core. The rotation of the valve core changes the size of the arc-shaped gap between the high and low pressure orifices and the spiral groove, breaking the resistance half-bridge balance, thereby causing the valve core to move axially under the action of hydraulic unbalanced force. For example, Chinese invention patent application number 2023115345545 discloses a two-dimensional electro-hydraulic servo valve based on a dry-wet separation transmission mechanism. This two-dimensional electro-hydraulic servo valve is equipped with two sets of torque amplification mechanisms, so that the torque finally output by the electro-mechanical converter to the valve core is the product of the amplification factors of the first-stage torque amplification mechanism and the second-stage torque amplification mechanism. The first-stage torque amplification mechanism includes a motor ball head and a crankshaft shift fork. The motor ball head and crankshaft shift fork are manufactured using a matching grinding method (precisely controlling the fitting accuracy and surface roughness of the motor ball head and crankshaft shift fork to ensure the performance and stability of the first-stage torque amplification mechanism). Therefore, if a component in the first-stage torque amplification mechanism malfunctions during the operation of this servo valve, the entire transmission mechanism must be replaced.

[0004] The crankshaft used in the aforementioned torque amplification mechanism employs a three-section structure, with the three sections connected by adhesive bonding or interference fit. This method has the following drawbacks: 1. Adhesive bonding limits the lifespan of the torque amplification mechanism, making it suitable only for experimental research and unsuitable for industrial production. 2. If an interference fit is used, the interference is typically achieved through techniques such as hard pressing, which can easily deform the crankshaft. This affects the accuracy of the entire torque amplification mechanism and makes it prone to jamming during operation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve. Compared to existing technologies, the transmission mechanism of the present invention eliminates complex machining steps such as grinding, making it easier to manufacture and applicable to industrial production.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] A π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve is characterized by: a connecting housing containing a parallel, independent wet operating chamber and a dry operating chamber; a primary torque amplification mechanism in the dry operating chamber and a secondary torque amplification mechanism in the wet operating chamber, the primary and secondary torque amplification mechanisms being connected; the secondary torque amplification mechanism includes a valve core lever and a π-axis, the valve core lever being movably connected to the π-axis at its lower end, and the π-axis being integrally formed.

[0008] Furthermore: the first-stage torque amplification mechanism includes a shift fork and a π-axis connecting lever. The lower part of the π-axis connecting lever is connected to the π-axis, and the top of the π-axis connecting lever is connected to a first ball head, which is placed in the shift fork groove on the upper part of the shift fork.

[0009] Furthermore: the π-axis has a fan-shaped swing section and connecting sections on both sides of the fan-shaped swing section. The bottom of the fan-shaped swing section is provided with a ball head through groove. The lower end of the valve core lever is connected to a second ball head, and the second ball head is slidably connected to the ball head through groove of the fan-shaped swing section.

[0010] Furthermore: the connecting housing has a window at the location of the dry operating chamber, and a detachable cover plate corresponding to the window is provided on the connecting housing.

[0011] Furthermore: one end of the π-axis extends into the dry operating chamber and is connected to the first-stage torque amplification mechanism, and two oppositely arranged wrench operating holes are opened on this end of the π-axis in the dry operating chamber.

[0012] Furthermore, the angle between the axis of the two wrench operating holes and the horizontal line is 12°.

[0013] Furthermore, a sealing and positioning structure is respectively fitted on the connecting parts on both sides of the fan-shaped swing part. The π-axis is rotatably connected to the sealing and positioning structure, and the sealing and positioning structure is fixedly connected to the connecting shell.

[0014] Furthermore: the sealing and positioning structure includes a plug ring and a bearing, both of which are sleeved on the connecting part, with the plug ring located outside the bearing and a sealing ring provided on the plug ring.

[0015] Furthermore, the length of the ball head through groove is matched with the design stroke spacing of the axial movement of the servo valve core.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. The π-axis used in this invention has an integrated structure, which has the advantage of being easier to process (such as wire cutting, turning, milling, etc.). At the same time, when a part is damaged, only the damaged part needs to be replaced, without replacing the entire transmission mechanism, which greatly reduces maintenance costs and time.

[0018] 2. This invention allows for precise initial zeroing of the valve core by using an Allen wrench to oscillate the π-axis. This method is not only reliable but also convenient and quick, significantly improving the accuracy and efficiency of the zeroing operation.

[0019] 3. Both the primary torque amplification mechanism and the secondary torque amplification mechanism of the present invention amplify the output torque of the motor by a factor, and the final torque output to the valve core is the product of the amplification factors of the primary torque amplification mechanism and the secondary torque amplification mechanism. Therefore, the output torque of the motor required for the valve core to rotate can be reduced, thereby allowing the use of a small motor, reducing the overall weight of the two-dimensional electro-hydraulic servo valve, reducing its size, and saving costs. Attached Figure Description

[0020] Figure 1 This is an overall external schematic diagram of the present invention with the shield removed;

[0021] Figure 2 This is a typical cross-sectional structural diagram of the present invention;

[0022] Figure 3 yes Figure 2 A magnified view of a section at point A in the middle;

[0023] Figure 4 This is a schematic diagram of the structure of the two-stage torque amplification mechanism of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the first-stage torque amplification mechanism of the present invention;

[0025] Figure 6 This is a left view of the π axis of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the present invention;

[0027] Figure 8 This is a cross-sectional view of the dry connecting sleeve of the present invention.

[0028] Reference numerals: 1-Connecting housing; 2-Electro-mechanical converter; 3-Valve body; 4-Wet operating chamber; 5-Dry operating chamber; 6-First-stage torque amplification mechanism; 7-Second-stage torque amplification mechanism; 8-Valve core lever; 9-π shaft; 10-Shift fork; 11-π shaft connecting lever; 12-First ball head; 13-Shift fork groove; 14-Fan-shaped swing part; 15-Connecting part; 16-Ball head through groove; 17-Window; 18-Shelter; 19-Wrench operating hole; 20-Plug ring; 21-Bearing; 22-Sealing ring; 23-Second ball head; 24-Valve core; 25-Internal hex wrench; 26-Anti-collision groove; 27-Wet connecting sleeve; 28-Dry connecting sleeve; 29-Intermediate connecting sleeve; 30-Opening groove. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of the present invention, preferred embodiments of the present invention are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting the present invention. For better illustration of this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present invention.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0031] like Figures 1 to 6 As shown, a π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve includes a connecting housing 1. An electro-mechanical converter 2 and a valve body 3 are respectively connected to both sides of the connecting housing 1. A wet operating chamber 4 and a dry operating chamber 5 are arranged side by side within the connecting housing 1. A first-stage torque amplification mechanism 6 is arranged in the dry operating chamber 5, and a second-stage torque amplification mechanism 7 is arranged in the wet operating chamber 4. The first-stage torque amplification mechanism 6 and the second-stage torque amplification mechanism 7 are connected to each other. The second-stage torque amplification mechanism 7 includes a valve core lever 8 and a π-axis 9. The lower end of the valve core lever 8 is movably connected to the π-axis 9, and the upper end of the valve core lever 8 is connected to the valve core 24 within the wet operating chamber 4. The π-axis 9 is integrally formed.

[0032] The primary torque amplification mechanism 6 includes a shift fork 10 and a π-axis connecting lever 11. The lower part of the π-axis connecting lever 11 is connected to the π-axis 9, and the top of the π-axis connecting lever 11 is connected to a first ball head 12. The first ball head 12 is placed in a shift fork groove 13 on the upper part of the shift fork 10, and the lower part of the shift fork 10 is connected to the electro-mechanical converter 2. The first ball head 12 makes point contact with the shift fork groove 13.

[0033] The π-axis 9 has a fan-shaped swing portion 14 and connecting portions 15 on both sides of the fan-shaped swing portion 14. The bottom of the fan-shaped swing portion 14 is provided with a ball-head through groove 16. The lower end of the valve core lever 8 is connected to a second ball head 23, which is slidably connected to the ball-head through groove 16 of the fan-shaped swing portion 14. The second ball head 23 makes point contact with the groove walls on both sides of the ball-head through groove 16. The centers of the fan-shaped swing portion 14 and the connecting portions 15 of the π-axis 9 of this invention are on the same axis, making the machining of the π-axis 9 more convenient.

[0034] In this invention, both the first ball head 12 and the second ball head 23 are standard parts. The π-shaft 9 does not require grinding with the second ball head 23 during machining, reducing machining steps. Furthermore, since the second ball head 23 and the π-shaft 9 do not require grinding, if one of the parts is damaged, only the damaged part needs to be replaced, without replacing the entire transmission mechanism.

[0035] The connecting housing 1 has a window 17 at the position of the dry operating chamber 5, and a cover plate 18 corresponding to the window 17 is provided on the connecting housing 1 for detachable connection.

[0036] The connecting housing 1 includes a wet connecting sleeve 27, a dry connecting sleeve 28, and an intermediate connecting sleeve 29. The intermediate connecting sleeve 29 is positioned between the wet connecting sleeve 27 and the dry connecting sleeve 28. The wet operating chamber 4 is located within the wet connecting sleeve 27, and the dry operating chamber 5 is located within the dry connecting sleeve 28. The wet connecting sleeve 27, the dry connecting sleeve 28, and the intermediate connecting sleeve 29 are detachably connected. A window 17 is provided on the dry connecting sleeve 28, and a corresponding cover plate 18 is provided on the window 17.

[0037] One end of the π shaft 9 extends into the dry operating chamber 5 and is connected to the first-stage torque amplification mechanism 6. Two wrench operation holes 19 are opened on this end of the π shaft 9 in the dry operating chamber 5. The angle between the axis of the two wrench operation holes 19 and the horizontal line is 12°, thereby ensuring that the π shaft 9 can rotate ±20°, so that the valve core 24 can also rotate ±4°.

[0038] During assembly, the valve core 24 of a two-dimensional electro-hydraulic servo valve often deviates from its rotational zero position. If this deviation exceeds 2.4° from the zero position, the entire valve will fail to operate. The deviation from the zero position of the valve core 24 is typically within single-digit or even minute-digit ranges. Directly adjusting the zero position of the valve core 24 requires adjustments to single-digit or minute-digit values, which is not only difficult to control in terms of precision but also cumbersome to operate. Therefore, this invention indirectly adjusts the zero position of the valve core 24 by adjusting the swing angle of the π-axis 9, ensuring precision while also being easier to operate. That is... Figure 7 As shown, both of the wrench operating holes 19 can be fitted with hex wrenches 25. The operator can directly adjust the zero position of the π shaft 9 by controlling the hex wrench 25, thereby adjusting the zero position of the valve core 24.

[0039] The two-stage torque amplification mechanism 7 of this invention achieves a five-fold torque amplification, i.e., a 5° rotation of the π-axis 9 corresponds to a 1° rotation of the valve core 24. Therefore, the method of indirectly adjusting the zero position of the valve core 24 by adjusting the swing angle of the π-axis 9 is more reliable. Furthermore, this invention provides two Allen wrenches 25 to eliminate gaps during the adjustment process and reduce dead zones.

[0040] Sealing and positioning structures are respectively fitted onto the connecting portions 15 on both sides of the fan-shaped swing portion 14. The π-axis 9 is rotatably connected to the sealing and positioning structure, and the sealing and positioning structure is fixedly connected to the connecting housing 1. Figure 8 As shown, an opening groove 30 is formed through the wet connecting sleeve 27, and the sealing and positioning structure is embedded in the wet connecting sleeve 27 through the opening groove 30. One end of the π shaft 9 extends into the dry operating chamber 5 through the opening groove 30 and connects to the π shaft connecting lever 11. The sealing and positioning structure can achieve a seal at the opening of the opening groove 30, preventing oil in the wet operating chamber 4 from entering the dry operating chamber 5.

[0041] The sealing and positioning structure includes a plug ring 20 and a bearing 21. Both the plug ring 20 and the bearing 21 are sleeved on the connecting part 15, with the plug ring 20 located outside the bearing 21. A sealing ring 22 is provided on the plug ring 20. An anti-collision groove 26 is provided on the valve body 3 to prevent the π shaft 9 from impacting the valve body 3. The secondary torque amplification mechanism 7 and the plug ring 20 seal the opening of the anti-collision groove 26. The internal pressure of the anti-collision groove 26 is balanced with the pressure of the dry operating chamber 5 on the secondary torque amplification mechanism 7, which can prevent the axial lateral force of the primary torque amplification mechanism 6 from acting on the crankshaft, causing it to undergo axial displacement and deformation.

[0042] The length of the ball head groove 16 matches the design stroke distance L of the axial movement of the servo valve core 24. When the valve core 24 moves axially, it drives the valve core lever 8 to move axially, thereby causing the second ball head 23 to move axially within the ball head groove 16.

[0043] Based on the description and accompanying drawings of this invention, those skilled in the art can easily manufacture or use the π-axis reduction transmission mechanism of a two-dimensional electro-hydraulic servo valve according to this invention, and can achieve the positive effects described in this invention.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve, characterized in that: The system includes a connecting housing (1), within which are arranged parallel, independent wet operating chambers (4) and dry operating chambers (5); a primary torque amplification mechanism (6) is provided in the dry operating chamber (5), and a secondary torque amplification mechanism (7) is provided in the wet operating chamber (4); the primary torque amplification mechanism (6) and the secondary torque amplification mechanism (7) are connected to each other; the secondary torque amplification mechanism (7) includes a valve core lever (8) and a π shaft (9), the valve core lever (8) is movably connected to the π shaft (9) at its lower end, and the π shaft (9) is integrally formed; The first-stage torque amplification mechanism (6) includes a shift fork (10) and a π-axis connecting lever (11). The lower part of the π-axis connecting lever (11) is connected to the π-axis (9), and the top of the π-axis connecting lever (11) is connected to a first ball head (12). The first ball head (12) is placed in the shift fork groove (13) on the upper part of the shift fork (10). The π axis (9) has a fan-shaped swing part (14) and connecting parts (15) on both sides of the fan-shaped swing part (14). The bottom of the fan-shaped swing part (14) is provided with a ball head through groove (16). The lower end of the valve core lever (8) is connected to a second ball head (23). The second ball head (23) is slidably connected to the ball head through groove (16) of the fan-shaped swing part (14). One end of the π shaft (9) extends into the dry operating chamber (5) and is connected to the first-stage torque amplification mechanism (6). The π shaft (9) has two oppositely arranged wrench operating holes (19) on this end of the dry operating chamber (5).

2. The π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The connecting housing (1) has a window (17) at the position of the dry operating chamber (5), and a detachable cover plate (18) corresponding to the window (17) is provided on the connecting housing (1).

3. The π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The angle between the axis of the two wrench operating holes (19) and the horizontal line is 12°.

4. The π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: Sealing and positioning structures are respectively fitted on the connecting parts (15) on both sides of the fan-shaped swing part (14). The π shaft (9) is rotatably connected to the sealing and positioning structure, and the sealing and positioning structure is fixedly connected to the connecting shell (1).

5. The π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve according to claim 4, characterized in that: The sealing and positioning structure includes a plug ring (20) and a bearing (21). Both the plug ring (20) and the bearing (21) are fitted onto the connecting part (15). The plug ring (20) is located outside the bearing (21), and a sealing ring (22) is provided on the plug ring (20).

6. The π-axis reduction transmission mechanism for a two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The length of the ball head through groove (16) matches the design stroke spacing of the axial movement of the servo valve core (24).

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