Jet pipe servo valve with low feedback pressure structure

Abstract

The invention relates to the field of electro-hydraulic servo valves, and discloses a jet pipe servo valve of a low feedback pressure structure, the jet pipe servo valve comprises a valve body, the valve body is provided with a jet space, a pilot valve core cavity and a main valve core cavity, a pilot valve core is slidably arranged in the pilot valve core cavity, and a main valve core is slidably arranged in the main valve core cavity; the jet flow amplifier comprises a jet flow pipe located in the jet flow space and a receiver used for receiving jet flow liquid, a first group of receiving holes and a second group of receiving holes are formed in the receiver, the first group of receiving holes are communicated with the pilot valve element cavity, and the second group of receiving holes are communicated with the main valve element cavity; in the jet flow direction of the jet flow pipe, the distance between the jet flow opening of the jet flow pipe and the first group of receiving holes is d1, and the distance between the jet flow opening of the jet flow pipe and the second group of receiving holes is d2, d1gt; and d2, the volume, occupied by the pilot valve element and the spring piece, of the valve body is reduced, so that the effect of reducing the volume size of the valve body is achieved, the technological difficulty and machining cost of the pilot spring are reduced, and the application scene of the servo valve is expanded.

Description

Technical Field

[0001] The present invention relates to the field of electro-hydraulic servo valves, in particular to a jet tube servo valve with a low feedback pressure structure. Background Art

[0002] An aircraft's braking system is a crucial component of its onboard equipment. Its function is to fully utilize the frictional resistance provided by the ground to the wheels, safely, reliably, and quickly enabling rotation and control during takeoff, landing, taxiing, and turning. The performance of the aircraft's braking system directly impacts the aircraft's rapid response, safe return, and sustained operational capability, ultimately impacting its overall performance. Electro-hydraulic servo valves are widely used in aircraft hydraulic brake systems to control wheel brake pressure. These valves connect the electrical and hydraulic components, receiving electrical command signals from the system and converting them into proportional signals with the appropriate polarity that can control load pressure. This results in the system outputting hydraulic power and a braking pressure proportional to the control current of the electrical signal.

[0003] The jet tube pressure servo valve is a common electro-hydraulic pressure servo valve. It utilizes a dry bridge-type permanent magnet torque motor. The jet tube is mounted on an armature supported by a thin-walled spring. Hydraulic oil enters the jet tube through a flexible pressure supply pipe. The torque motor drives the armature to deflect the jet tube. Hydraulic oil ejected from the jet tube nozzle enters two receiving holes connected to the cavities at both ends of the spool, pushing the spool to move. The displacement is proportional to the pressure difference across the main valve. A spring plate and feedback spring wire are installed on the side of the jet tube. The end of the feedback spring wire is inserted into a small groove in the center of the pilot valve spool. Movement of the spool pushes the feedback spring wire, providing force feedback to the torque motor.

[0004] Existing jet-tube pressure servo valves consist of a pilot spool and a main spool. A feedback spring is connected between the pilot spool and the jet tube. The main spool slides to control whether the load port is aligned with or blocked from the oil inlet or return port. For example, according to the Chinese invention patent entitled "A Pressure Servo Valve, Pressure Control Method, and Electro-Hydraulic Actuation System," with application number "CN202211712163.3," the cavities at both ends of the pilot spool communicate with the cavities at both ends of the main spool, while the two receiving holes communicate with the cavities at both ends of the pilot spool's spool. This ensures that the hydraulic oil ejected from the jet-tube nozzle exerts equal pressure on both the pilot and main spools. To ensure the pilot spool can function effectively as a pressure feedback mechanism, the spring attached to the pilot spool must possess sufficient stiffness. In existing technology, this requires increasing the spring diameter to meet this stiffness requirement. However, the increased size of the pilot spring increases the overall size of the servo valve, limiting its application scenarios. Summary of the Invention

[0005] In response to the above-mentioned deficiencies or defects in the prior art, the present invention provides a jet tube servo valve with a low feedback pressure structure, which can reduce the pressure borne by the pilot valve core. While meeting the pressure feedback function, it adopts a small-volume pilot valve core and a soft spring part, reducing the volume of the pilot valve core and the spring part occupied by the valve body, thereby achieving the effect of reducing the volume and weight of the valve body, meeting the aircraft weight reduction design requirements and expanding the application scenarios of the servo valve.

[0006] In order to achieve the above-mentioned object, the present invention provides a jet tube servo valve with a low feedback pressure structure, comprising:

[0007] A valve body is provided with a jet space, a pilot valve core cavity and a main valve core cavity. A pilot valve core is slidably provided in the pilot valve core cavity. A first elastic member is connected between the pilot valve core and the side wall of the pilot valve core cavity. A main valve core is slidably provided in the main valve core cavity. A second elastic member is connected between the main valve core and the side wall of the main valve core cavity.

[0008] a jet amplifier, the jet amplifier comprising a jet tube located in the jet space and a receiver for receiving the jet liquid, the receiver having a first group of receiving holes and a second group of receiving holes, the first group of receiving holes being in communication with the pilot valve core cavity, and the second group of receiving holes being in communication with the main valve core cavity;

[0009] Along the jet direction of the jet tube, the distance between the jet orifice of the jet tube and the first group of receiving holes is d1, and the distance between the jet orifice of the jet tube and the second group of receiving holes is d2, wherein: d1>d2.

[0010] In some embodiments, the pilot valve core divides the pilot valve core cavity into a first cavity and a second cavity that are not connected to each other, and the first elastic member is connected between the pilot valve core and the side wall of the first cavity and / or the second cavity; the main valve core divides the main valve core cavity into a third cavity and a fourth cavity that are not connected to each other, and the second elastic member is connected between the main valve core and the side wall of the third cavity and / or the fourth cavity;

[0011] The first group of receiving holes includes a first receiving hole and a second receiving hole distributed along the offset direction of the jet tube, the first receiving hole is connected to the first cavity, and the second receiving hole is connected to the second cavity; the second group of receiving holes includes a third receiving hole and a fourth receiving hole distributed along the offset direction of the jet tube, the third receiving hole is connected to the third cavity, and the fourth receiving hole is connected to the fourth cavity.

[0012] In some embodiments, when projected along the jet direction of the jet pipe, the area of the first receiving hole facing the jet port of the jet pipe is S1, the area of the second receiving hole facing the jet port of the jet pipe is S2, the area of the third receiving hole facing the jet port of the jet pipe is S3, and the area of the fourth receiving hole facing the jet port of the jet pipe is S4. At any moment during the offset process of the jet pipe, S1 ≤ S3 and S2 ≤ S4.

[0013] In some embodiments, at any moment during the offset process of the jet pipe, S1 < S3 and S2 < S4.

[0014] In some embodiments, the pilot valve core divides the pilot valve core cavity into a first cavity and a second cavity that are not connected to each other, and a first elastic member is connected between the pilot valve core and the side walls of the first cavity and / or the second cavity; the main valve core divides the main valve core cavity into a third cavity and a fourth cavity that are not connected to each other, and a second elastic member is connected between the main valve core and the side walls of the third cavity and / or the fourth cavity;

[0015] The first group of receiving holes includes a fifth receiving hole, and the fifth receiving hole is connected to the first cavity; the second group of receiving holes includes a sixth receiving hole, and the sixth receiving hole is connected to the third cavity;

[0016] The valve body has a return port, and both the second cavity and the fourth cavity are connected to the return port.

[0017] In some embodiments, when projected along the jet direction of the jet pipe, the area of the fifth receiving hole facing the jet port of the jet pipe is S5, and the area of the sixth receiving hole facing the jet port of the jet pipe is S6. At any moment during the offset process of the jet pipe, S5 ≤ S6.

[0018] In some embodiments, when projected along the jet direction of the jet pipe, during the offset process of the jet pipe, the fifth receiving hole and the sixth receiving hole start to overlap with the jet port of the jet pipe simultaneously.

[0019] In some embodiments, the valve body is further provided with a load port, a feedback channel is connected between the load port and the fourth cavity, and a part of the main valve core extends into the feedback channel and divides the fourth cavity and the feedback channel.

[0020] In some embodiments, when projected along the sliding direction of the main valve core, the cross-section of the feedback channel is smaller than the cross-section of the third cavity, so that the acting force exerted on the main valve core by the jet pressure is greater than the acting force exerted on the main valve core by the output pressure at the load port.

[0021] A jet tube servo valve with a low feedback pressure structure, utilizing the above-mentioned technical solution of the present invention, has the following effects: the receiving holes for receiving the jet liquid are distributed in a stepped manner along the jet direction, and the distance between the receiving holes connected to the pilot valve core cavity and the jet tube jet port is greater than the distance between the receiving holes connected to the main valve core cavity and the jet tube jet port. The jet pressure experienced by the pilot valve core is lower than that experienced by the main valve core. While still meeting the pressure feedback function, a smaller pilot valve core and a more flexible spring member can be used, thereby reducing the volume occupied by the pilot valve core and spring member in the valve body, thereby reducing the size and weight of the valve body, lowering the difficulty and cost of the pilot spring process, meeting aircraft weight reduction design requirements, and expanding the application scenarios of the servo valve.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the installation diagram of the valve body and jet amplifier and the internal structure diagram of the valve body;

[0024] Figure 2 Schematic diagram of the internal structure of the jet tube servo valve with low feedback pressure structure of the first embodiment and the second embodiment;

[0025] Figure 3 is a side view schematic diagram of the jet tube and the receiver of the first embodiment and the second embodiment;

[0026] Figure 4 yes Figure 3 Axonometric perspective diagram of

[0027] Figure 5 This is a schematic diagram of the change in the facing position between the jet port of the jet tube and the receiving hole during the use of the existing jet tube pressure servo valve;

[0028] Figure 6 1 is a schematic diagram showing the change in the facing position between the jet port of the jet tube and the receiving hole during use of the jet tube pressure servo valve of Example 1;

[0029] Figure 7 1 is a schematic diagram showing the change in the facing position between the jet port of the jet tube and the receiving hole during use of the jet tube pressure servo valve of Example 2;

[0030] Figure 8 Schematic diagram of the internal structure of the jet tube servo valve with low feedback pressure structure of the third and fourth embodiments;

[0031] Figure 9 is an axial perspective schematic diagram of the jet tube and receiver of the third and fourth embodiments;

[0032] Figure 101 is a schematic diagram showing the change in the facing position between the jet port of the jet tube and the receiving hole during use of the jet tube pressure servo valve of Example 3;

[0033] Figure 11 This is a schematic diagram of the change in the facing position between the jet port of the jet tube and the receiving hole during use of the jet tube pressure servo valve with a single receiving hole;

[0034] Figure 12 3. It is a schematic diagram showing the change in the facing position between the jet port of the jet tube and the receiving hole during use of the jet tube pressure servo valve of the fourth embodiment.

[0035] Description of Reference Numerals

[0036] 10. Valve body; 101. First oil supply port; 102. Second oil supply port; 103. Load port; 104. Return port; 105. Feedback channel; 11. Jet space; 12. Pilot valve core cavity; 121. First cavity; 122. Second cavity; 123. Pilot valve core; 124. First elastic member; 13. Main valve core cavity; 131. Third cavity; 132. Fourth cavity; 133. Main valve core; 134. Second elastic member; 14. Jet discharge 15. Fluidic tube; 16. Receiver; 16a. First set of receiving holes; 16b. Second set of receiving holes; 161. First receiving hole; 162. Second receiving hole; 163. Third receiving hole; 164. Fourth receiving hole; 165. Fifth receiving hole; 166. Sixth receiving hole; 17. Flexible tube; 18. Feedback spring wire assembly; 181. Spring plate; 182. Feedback spring wire; 19. Torque motor; 191. Permanent magnet; 192. Coil assembly; 193, armature; 194, upper magnetic conductor; 195, lower magnetic conductor; 196, mounting base; 30, left receiving hole; 40, right receiving hole; 50, single receiving hole; X, jet tube offset direction; Y, jet direction; S1, area of ​​the jet tube jet orifice facing the first receiving hole along the jet direction; S2, area of ​​the jet tube jet orifice facing the second receiving hole along the jet direction; S3, area of ​​the jet tube jet orifice facing the third receiving hole along the jet direction Area; S4, the area of ​​the jet outlet of the jet tube facing the fourth receiving hole along the jet direction; S5, the area of ​​the jet outlet of the jet tube facing the fifth receiving hole along the jet direction; S6, the area of ​​the jet outlet of the jet tube facing the sixth receiving hole along the jet direction; S7, the area of ​​the jet outlet of the jet tube facing the left receiving hole along the jet direction; S8, the area of ​​the jet outlet of the jet tube facing the right receiving hole along the jet direction; S9, the area of ​​the jet outlet of the jet tube facing the single receiving hole along the jet direction. DETAILED DESCRIPTION

[0037] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0038] In the present invention, unless otherwise specified, directional terms such as "upper" and "lower" generally refer to directions in the assembled state. "Inside" and "outside" refer to inside and outside relative to the outline of each component itself.

[0039] Combined with attachment Figure 1 , Attachment Figure 2 The present invention discloses a low-feedback-pressure jet tube servo valve, comprising a valve body 10, a torque motor 19, a flexible tube 17, and a jet amplifier 14. The valve body 10 defines a jet space 11, a pilot valve core cavity 12, a main valve core cavity 13, a first oil supply port 101, a second oil supply port 102, a load port 103, and a return port 104.

[0040] A pilot valve core 123 slides within the pilot valve core chamber 12. A first elastic member 124 is connected between the pilot valve core 123 and the sidewall of the pilot valve core chamber 12. A main valve core 133 slides within the main valve core chamber 13. A second elastic member 134 is connected between the main valve core 133 and the sidewall of the main valve core chamber 13. The main valve core 133 slides to adjust the degree of connectivity between the first oil supply port 101 and the load port 103, thereby adjusting the output pressure at the load port 103. The first elastic member 124 and the second elastic member 134 are spring members. The jet amplifier 14 includes a jet tube 15 located in the jet space 11 and a receiver 16 for receiving the jet liquid. A feedback spring wire assembly 18 is connected between the pilot valve core 123 and the jet tube 15. The feedback spring wire assembly 18 includes a spring plate 181 fixed on the jet tube 15 and a feedback spring wire connected between the spring plate 181 and the pilot valve core 123, which feeds back the sliding distance of the pilot valve core 123 to the offset degree of the jet tube 15.

[0041] The torque motor 19 includes a permanent magnet 191, a coil assembly 192, an armature 193, an upper magnetic conductor 194, a lower magnetic conductor 195, and a mounting base 196. The mounting base 196 is fixedly mounted on the valve body 10. One end of the flexible tube 17 is connected to the second oil supply port 102, and the other end is connected to the jet tube 15. The jet tube 15 and the flexible tube 17 are mounted on the armature 193. Oil is supplied to the flexible tube 17 and the jet tube 15 through the second oil supply port 102, and the jet tube 15 then sprays the jet liquid into the receiving hole. When the torque motor 19 receives an electrical signal, the armature 193 rotates, causing the flexible tube 17 and the jet tube 15 to deflect. The greater the input current received by the torque motor 19, the greater the degree of deflection of the jet tube 15.

[0042] Combined with attachment Figure 3Receiver 16 has a first set of receiving holes 16a and a second set of receiving holes 16b. The first set of receiving holes 16a communicates with the pilot valve core chamber 12, while the second set of receiving holes 16b communicates with the main valve core chamber 13. Specifically, the receiving holes and the pilot valve core chamber 12 and the main valve core chamber 13 can be connected by pipes, or passages can be defined within valve body 10 to connect the receiving holes with the pilot valve core chamber 12 and the main valve core chamber 13. Some of the passages or pipes are shown disconnected.

[0043] Along the jet direction of jet tube 15, the distance between the jet orifice of jet tube 15 and the first group of receiving holes 16a is d1, and the distance between the jet orifice of jet tube 15 and the second group of receiving holes 16b is d2, where d1>d2. Because the distance between the jet orifice of jet tube 15 and the first group of receiving holes 16a is greater than the distance between the jet orifice of jet tube 15 and the second group of receiving holes 16b, when the jet pressure ejected from the jet orifice of jet tube 15 is applied to the receiving holes, the jet pressure transmission path received by the first group of receiving holes 16a is greater than the jet pressure transmission path received by the second group of receiving holes 16b. In other words, the jet pressure loss received by the first group of receiving holes 16a is greater than the jet pressure loss received by the second group of receiving holes 16b. Therefore, the jet pressure received by the first group of receiving holes 16a is less than the jet pressure received by the second group of receiving holes 16b. The first set of receiving holes 16a communicates with the pilot valve core chamber 12, allowing the jet pressure received by the first set of receiving holes 16a to act on the pilot valve core 123. The second set of receiving holes 16b communicates with the main valve core chamber 13, allowing the jet pressure received by the second set of receiving holes 16b to act on the main valve core 133. In summary, the jet pressure received by the receiving holes is proportional to the distance between the jet orifice of the jet tube 15 and the receiving holes. Generally, the cross-section of the jet orifice of the jet tube 15 along the jet direction is smaller than the cross-section of the receiving hole, allowing the receiving hole to fully receive the jet fluid ejected from the jet orifice of the jet tube 15.

[0044] During the use of the existing jet tube pressure servo valve, the jet pressures borne by the main valve core 133 and the pilot valve core 123 are the same at any time. When the jet pressures borne by the main valve core 133 of the existing jet tube pressure servo valve and the jet tube pressure servo valve in the present application are equal, the jet pressure borne by the pilot valve core 123 in the jet tube pressure servo valve in the present application is smaller, and the structural strength requirements for the pilot valve core 123 and the first elastic member 124 are lower. Therefore, under the premise that the range of jet pressure values ​​during the sliding process of the main valve core 133 is the same, the jet tube pressure servo valve in the present application can adopt a smaller pilot valve core 123 and a more flexible first elastic member 124 than those in the existing servo valve. By reducing the size of the pilot valve core 123, the first elastic member 124 and the pilot valve core cavity 12, the purpose of reducing the volume of the valve body 10 is achieved, making the entire valve body 10 lighter and expanding the application scenarios.

[0045] Specifically, this application discloses the following two embodiments:

[0046] Example 1

[0047] As attached Figure 2 As shown, the pilot valve core 123 divides the pilot valve core chamber 12 into a first cavity 121 and a second cavity 122 that are not connected to each other. A first elastic member 124 is connected between the pilot valve core 123 and the sidewalls of the first cavity 121 and / or the second cavity 122. In this embodiment, the pilot valve core 123 slides left and right within the pilot valve core chamber 12, with the first cavity 121 located to the right of the pilot valve core 123 and the second cavity 122 located to the left of the pilot valve core 123. The first elastic member 124 is connected between the pilot valve core 123 and the sidewalls of both the first cavity 121 and the second cavity 122. The main valve core 133 divides the main valve core chamber 13 into a third cavity 131 and a fourth cavity 132 that are not connected to each other. A second elastic member 134 is connected between the main valve core 133 and the sidewalls of the third cavity 131 and / or the fourth cavity 132. In this embodiment, the main valve core 133 slides left and right in the main valve core cavity 13, the third cavity 131 is located on the right side of the main valve core 133, the fourth cavity 132 is located on the left side of the main valve core 133, and the second elastic member 134 is connected between the left end of the main valve core 133 and the left side wall of the fourth cavity 132.

[0048] Combined with attachment Figure 4 The first group of receiving holes 16a includes a first receiving hole 161 and a second receiving hole 162 distributed along the offset direction of the jet tube 15. The first receiving hole 161 is connected to the first cavity 121, and the second receiving hole 162 is connected to the second cavity 122. The second group of receiving holes 16b includes a third receiving hole 163 and a fourth receiving hole 164 distributed along the offset direction of the jet tube 15. The third receiving hole 163 is connected to the third cavity 131, and the fourth receiving hole 164 is connected to the fourth cavity 132. In this embodiment, the jet tube 15 deflects from left to right under the action of the torque motor 19. Therefore, the first receiving hole 161 and the second receiving hole 162 are distributed in the left-right direction, and the third receiving hole 163 and the fourth receiving hole 164 are also distributed in the left-right direction. Specifically, the first receiving hole 161 is located to the right of the second receiving hole 162, and the third receiving hole 163 is located to the right of the fourth receiving hole 164.

[0049] First of all, it should be noted that the sliding force relationship of the pilot valve core 123 is: P1=P2+P F1 P1 is the jet pressure received by the first receiving hole 161; P2 is the jet pressure received by the second receiving hole 162; P F1 is the pressure generated by the force exerted by the first elastic member 124 on the pilot valve core 123, where P F1 ≥0 and P1≥P2. The relationship between the sliding force of the main valve core 133 is: P3=P4+P F2. P3 is the jet pressure received by the third receiving hole 163; P4 is the jet pressure received by the fourth receiving hole 164; P F2 is the pressure generated by the acting force exerted by the second elastic member 134 on the main spool 133, where P F2 ≥0 and P3≥P4.

[0050] For the existing jet pipe pressure servo valve, in combination with the attached Figure 5 , it has two receiving holes and is distributed in the left - right direction. Additionally, in the existing jet pipe pressure servo valve, the first cavity 121 is connected to the third cavity 131, and the second cavity 122 is connected to the fourth cavity 132. For the sake of easy explanation, the two receiving holes are respectively called the left receiving hole 30 and the right receiving hole 40. The left receiving hole 30 is connected to the second cavity 122 and the fourth cavity 132, and the right receiving hole 40 is connected to the first cavity 121 and the third cavity 131. Without considering the zero - position offset, in the initial state, along the jet direction of the jet pipe 15, the jet port of the jet pipe 15 is located in the middle of the left receiving hole 30 and the right receiving hole 40. At this time: P1 = P2 = P3 = P4.

[0051] The zero - position offset refers to the offset of the relative position between the jet pipe 15 and the receiver 16 due to the influence of thermal expansion and contraction or mechanical acting forces of external conditions.

[0052] In the existing jet pipe pressure servo valve, under the action of the torque motor 19, the jet pipe 15 deflects from left to right. During the deflection process of the jet pipe 15, P1 and P3 remain equal and increase synchronously, and P2 and P4 remain equal and decrease synchronously. At any moment during the deflection process: P1 = P3 and P2 = P4. Assume that the value range of P1 and P3 is (P0’~P0”) and P0’ < P0”. Then, in the existing jet pipe pressure servo valve, the maximum jet pressure borne by the pilot spool 123 and the main spool 133 is P0”. That is to say, the stiffness and size of the first elastic member 124 need to ensure that the first elastic member 124 can at least withstand the pressure action of P0”.

[0053] In combination with the attached Figure 6In the jet tube pressure servo valve of this embodiment, projected along the jet direction of the jet tube 15, the first receiving hole 161, the second receiving hole 162, the third receiving hole 163, and the fourth receiving hole 164 are arranged in a rectangular array. Ignoring zero offset, in the initial state, the jet orifice of the jet tube 15 is located at the center of the array. The areas facing the jet orifice of the jet tube 15 and the first, second, third, and fourth receiving holes 161, 162, 163, and 164 are equal. Specifically, projected along the jet direction of the jet tube 15, the area facing the jet orifice of the jet tube 15 by the first receiving hole 161 is S1, the area facing the jet orifice of the jet tube 15 by the second receiving hole 162 is S2, the area facing the jet orifice of the jet tube 15 by the third receiving hole 163 is S3, and the area facing the jet orifice of the jet tube 15 by the fourth receiving hole 164 is S4. In the initial state, S1 = S2 = S3 = S4.

[0054] During the use process (i.e., during the process of the jet pipe 15 offsetting from left to right), the facing areas between the jet port of the jet pipe 15 and the first receiving hole 161 and the third receiving hole 163 are equal and increase synchronously, and the facing areas between the jet port of the jet pipe 15 and the second receiving hole 162 and the fourth receiving hole 164 are equal and decrease synchronously. Since the distances between the first receiving hole 161 and the second receiving hole 162 and the jet port of the jet pipe 15 are greater than the distances between the third receiving hole 163 and the fourth receiving hole 164 and the jet port of the jet pipe 15, under the premise of S1 = S3, P1 < P3. That is: during the offsetting process of the jet pipe 15, P1 and P3 increase, and P2 and P4 decrease. Therefore, at any moment during the offsetting process of the jet pipe 15, P1 is the maximum jet pressure borne by the pilot valve core 123 at that moment, and P3 is the maximum jet pressure borne by the main valve core 133 at that moment. Assume that the value range of P1 is (P1’~P1”), and the value range of P3 is (P3’~P3”), then P1’ < P1” and P3’ < P3” and P1” < P3”. In this embodiment, during the entire offsetting process of the jet pipe 15, the maximum jet pressure that the pilot valve core 123 needs to bear is P1”, and the maximum jet pressure that the main valve core 133 needs to bear is P3”. To sum up, when the jet pressures borne by the main valve core 133 in the existing servo valve and the servo valve of this embodiment are equal, that is: when the value range of P3 in the existing servo valve is equal to the value range of P3 in this embodiment, P0’ = P3’ and P0” = P3”. Since the maximum jet pressure borne by the pilot valve core 123 in the existing servo valve is equal to the maximum jet pressure borne by the main valve core 133, while the maximum jet pressure borne by the pilot valve core 123 in this embodiment is less than the maximum jet pressure borne by the main valve core 133. Therefore, on the premise that the value ranges of the jet pressures during the sliding process of the main valve core 133 are the same, the maximum jet pressure borne by the pilot valve core 123 in this embodiment is relatively smaller than the maximum jet pressure borne by the pilot valve core 123 in the prior art, that is, P1” < P3” = P0”. The strength requirements for the pilot valve core 123 and the first elastic member 124 are lower. Thus, in this embodiment, a smaller-sized pilot valve core 123 and a more flexible and thinner first elastic member 124 can be used, reducing the occupied space of the pilot valve core 123, the first elastic member 124, and the pilot valve core cavity 12, and ultimately reducing the volume of the entire servo valve and expanding the application scenarios of the servo valve.

[0055] Embodiment 2

[0056] Combined with the attached Figure 7, compared with the first embodiment, the difference in this embodiment is as follows: When projected along the jet direction of the jet pipe 15 in the initial state, the area S1 of the first receiving hole 161 facing the jet port of the jet pipe 15 is smaller than the area S3 of the third receiving hole 163 facing the jet port of the jet pipe 15; the area S2 of the second receiving hole 162 facing the jet port of the jet pipe 15 is smaller than the area S4 of the fourth receiving hole 164 facing the jet port of the jet pipe 15. That is: S1 < S3 and S2 < S4. And during the offset process of the jet pipe 15, the facing area between the jet port of the jet pipe 15 and the first receiving hole 161 and the third receiving hole 163 increases synchronously and maintains S1 < S3, and the facing area between the jet port of the jet pipe 15 and the second receiving hole 162 and the fourth receiving hole 164 decreases synchronously and maintains S2 < S4.

[0057] The jet pressure received by the receiving hole is proportional to the area of the jet port of the jet pipe 15 facing the receiving hole. That is, the larger the area of the receiving hole facing the jet port of the jet pipe 15, the greater the jet pressure received by the receiving hole. In this embodiment, the distances between the first receiving hole 161, the second receiving hole 162 and the jet port of the jet pipe 15 are greater than the distances between the third receiving hole 163, the fourth receiving hole 164 and the jet port of the jet pipe 15, and the areas of the first receiving hole 161, the second receiving hole 162 facing the jet port of the jet pipe 15 are smaller than the areas of the third receiving hole 163, the fourth receiving hole 164 facing the jet pipe 15. It is ensured that at any moment during the offset process of the jet pipe 15, the jet pressure received by the third receiving hole 163 is greater than the jet pressure received by the first receiving hole 161. That is: the maximum jet pressure borne by the pilot spool 123 is less than the maximum jet pressure borne by the main spool 133. On the premise that the range of the jet pressure values during the sliding process of the main spool 133 is the same, the maximum jet pressure borne by the pilot spool 123 in this embodiment is smaller than the maximum jet pressure borne by the pilot spool 123 in the prior art. In this embodiment, a pilot spool 123 with a smaller volume and a more flexible and thinner first elastic member 124 can be used, so that the space occupied by the pilot spool 123, the first elastic member 124 and the pilot spool cavity 12 is reduced, and finally the volume of the entire servo valve can be reduced, expanding the application scenarios of the servo valve.

[0058] Embodiment Three

[0059] Combined with attached Figure 8 , attached Figure 9 and attached Figure 10 , compared with the first embodiment, the difference in this embodiment is as follows: The first group of receiving holes 16a includes a fifth receiving hole 165, and the fifth receiving hole 165 is connected to the first cavity 121. The second group of receiving holes 16b includes a sixth receiving hole 166, and the sixth receiving hole 166 is connected to the third cavity 131. The second cavity 122 and the fourth cavity 132 are both connected to the return port 104. In this embodiment, both P2 and P4 are equal to the pressure at the return port 104 and remain constant.

[0060] In this embodiment, the area of the fifth receiving hole 165 facing the jet port of the jet tube 15 is S5, and the area of the sixth receiving hole 166 facing the jet port of the jet tube 15 is S6. Projecting along the jet direction of the jet tube 15, without considering the zero position offset, in the initial state, the jet port of the jet tube 15 is located on the left side of the fifth receiving hole 165 and the sixth receiving hole 166, and both S5 and S6 are zero. During the offset process of the jet tube 15, the fifth receiving hole 165 and the sixth receiving hole 166 simultaneously start to overlap with the jet port of the jet tube 15, and S5 = S6 at any moment during the offset process of the jet tube 15.

[0061] During use (that is, during the process of the jet tube 15 offsetting from left to right), the facing areas of the jet port of the jet tube 15 with the fifth receiving hole 165 and the sixth receiving hole 166 are equal and increase synchronously, thereby increasing P1 and P3 to drive the pilot spool 123 and the main spool 133 to slide to the left. Since the distance between the fifth receiving hole 165 and the jet port of the jet tube 15 is greater than the distance between the sixth receiving hole 166 and the jet port of the jet tube 15, under the premise of S5 = S6, P1 < P3. That is: during the offset process of the jet tube 15, P1 and P3 increase, and P2 and P4 remain constant. Therefore, at any moment during the offset process of the jet tube 15, P1 is the maximum jet pressure borne by the pilot spool 123 at that moment, and P3 is the maximum jet pressure borne by the main spool 133 at that moment.

[0062] Assume that the value range of P1 is (P1' to P1"), the value range of P3 is (P3' to P3"), and P1' < P1", P3' < P3", and P1" < P3". In this embodiment, during the entire offset process of the jet tube 15, the maximum jet pressure that the pilot spool 123 needs to bear is P1", and the maximum jet pressure that the main spool 133 needs to bear is P3".

[0063] On the premise that the value range of the jet pressure during the sliding process of the main spool 133 is the same, the maximum jet pressure borne by the pilot spool 123 in this embodiment is smaller than the maximum jet pressure borne by the pilot spool 123 in the prior art. In this embodiment, a pilot spool 123 with a smaller volume and a more flexible and thinner first elastic member 124 can be adopted, so that the space occupied by the pilot spool 123, the first elastic member 124, and the pilot spool cavity 12 is reduced, and finally the volume of the entire servo valve can be reduced, expanding the application scenarios of the servo valve.

[0064] In addition, in the present embodiment, the jet pressure is applied only to one side of the pilot valve core 123 and the main valve core 133, thereby eliminating the correlation between the back pressure of the valve core and the jet pressure, increasing the working stroke of the jet tube 15 offset and reducing the recovery pressure gain in the receiving hole, thereby reducing the sensitivity of the relative position change of the jet tube 15 and the receiver 16 to the change of the servo valve output pressure, and improving the output stability of the servo valve.

[0065] Specifically, in this embodiment, the right end surfaces of both the pilot valve core 123 and the main valve core 133 are subjected to the jet pressure, while the left end surfaces of the pilot valve core 123 and the main valve core 133 are subjected to back pressure, where back pressure refers to the force exerted on the valve core by the pressure that hinders the movement of the valve core. The back pressure of the pilot valve core 123 is the force exerted on the pilot valve core 123 by the pressure at the return port 104 and the force exerted on the pilot valve core 123 by the first elastic member 124. The back pressure of the main valve core 133 is the force exerted on the pilot valve core 123 by the pressure at the return port 104 and the force exerted on the main valve core 133 by the second elastic member 134.

[0066] To further illustrate, during the deflection of the jet tube 15 of the existing jet tube pressure servo valve, the area of ​​the right receiving hole 40 facing the jet orifice of the jet tube 15 increases, while the area of ​​the left receiving hole 30 facing the jet orifice of the jet tube 15 decreases. This creates a pressure differential between the right receiving hole 40 and the left receiving hole 30, resulting in a pressure gain greater than zero. When the jet tube 15 deflects until the jet liquid enters only the right receiving hole 40, if the jet tube 15 continues to deflect rightward (without moving out of the right side of the right receiving hole 40), the pressure differential between the right receiving hole 40 and the left receiving hole 30 remains unchanged. When the jet liquid enters only the right receiving hole 40, the pressure differential between the right receiving hole 40 and the left receiving hole 30 remains unchanged, i.e., the pressure gain is zero. During the deflection of the jet tube 15 from its initial state to the state where the receiving hole pressure gain is zero, the distance the jet tube 15 deflects represents its operating range, which is equal to the radius of the jet orifice of the jet tube 15.

[0067] In this embodiment, the jet pressure is applied only to the right end of the valve core. The jet pressure received by the fifth receiving hole 165 is entirely applied to the right end of the pilot valve core 123, and the jet pressure received by the sixth receiving hole 166 is entirely applied to the right end of the main valve core 133. For each of the fifth receiving hole 165 or the sixth receiving hole 166 to receive the jet pressure, the deflection stroke of the jet tube 15 is greater than the radius of the jet opening of the jet tube 15.

[0068] Specifically, in conjunction with Figure 11, the jet pressure of the jet outlet of the jet tube 15 is received by a single receiving hole as an example for explanation. For the convenience of explanation, the receiving hole is referred to as a single receiving hole 50 (in this embodiment, the single receiving hole 50 can be regarded as the fifth receiving hole 165 or the sixth receiving hole 166). In the initial state, the area facing the jet outlet of the jet tube 15 and the single receiving hole 50 along the jet direction is zero. After receiving the current signal, the torque motor 19 drives the jet tube 15 to deflect to the right, increasing the area facing the jet outlet of the jet tube 15 and the single receiving hole 50, thereby increasing the jet pressure received by the single receiving hole 50. At this time, the pressure gain of the single receiving hole 50 is greater than zero. When the area facing the jet outlet of the jet tube 15 and the single receiving hole 50 is the cross-section of the jet outlet, the jet pressure received by the single receiving hole 50 is the maximum. If the jet tube 15 continues to deflect to the right, the jet pressure received by the single receiving hole 50 no longer changes, and the pressure gain of the single receiving hole 50 is zero. During the process of jet tube 15 deflecting from its initial state to a state where the pressure gain of the receiving hole is zero, the distance jet tube 15 deflects is its operating range, which is equal to the diameter of the jet orifice of jet tube 15. Compared to the receiving hole arrangement in the prior art, the deflection operating range of jet tube 15 is larger. Taking zero offset into account, this reduces the sensitivity of the relative position of jet tube 15 and receiver 16 to changes in the servo valve output pressure, thereby improving the output stability of the servo valve.

[0069] For example, assuming the jet orifice and receiving hole of jet tube 15 are the same size, assume that in a conventional jet tube pressure servo valve with left and right receiving holes 30 and 40, the operating stroke of jet tube 15 is 0.1 mm. In a jet tube pressure servo valve with a single receiving hole 50, the operating stroke of jet tube 15 is 0.2 mm, and the zero offset of jet tube 15 is 0.01 mm. For the conventional jet tube pressure servo valve, the impact of the zero offset is 0.01 mm / 0.1 mm, or 0.1. For a jet tube pressure servo valve with a single receiving hole 50, the impact of the zero offset is 0.01 mm / 0.2 mm, or 0.05. The smaller the impact of the zero offset, the less sensitive the output pressure is to the zero offset, and the more stable the performance of the jet tube pressure servo valve.

[0070] In addition, the jet tube pressure servo valve with a single receiving hole 50 reduces the recovery pressure gain compared to the existing jet tube pressure servo valve.

[0071] For example: Assuming that the displacement of the jet tube 15 is Δε, during the operation of the existing jet tube pressure servo valve, the overlapping area S8 between the jet port of the jet tube 15 and the right receiving hole 40 changes from A1 to A1', and the overlapping area S7 between the jet port of the jet tube 15 and the left receiving hole 30 changes from A2 to A2'. Then, the recovery pressure gain of the existing jet tube pressure servo valve is: Δp1 = k p[(A′1-A1)-(A′2-A2)]. During the operation of the jet tube pressure servo valve with a single receiving hole 50, since only a single receiving hole is provided and it is equivalent to the right receiving hole 40 in the existing jet tube pressure servo valve, the recovery pressure gain of the jet tube pressure servo valve with a single receiving hole 50 is: Δp2=k p (A′1-A1). Where k p Is a constant.

[0072] Since A′2 is smaller than A2, that is, A′2-A2 is smaller than 0, Δp1 is larger than Δp2. Therefore, the recovery pressure gain of the conventional jet tube pressure servo valve is greater than that of the jet tube pressure servo valve with a single receiving hole 50.

[0073] The pressure gain of the jet tube pressure servo valve refers to the sensitivity of the output pressure to the relative position of the jet tube 15 and the receiving hole. Given the same relative position change between the jet tube 15 and the receiving hole, the greater the pressure gain, the more sensitive the servo valve is to external disturbances and the greater the output pressure change. Reducing the pressure gain can reduce the output pressure sensitivity and improve the output stability of the jet tube pressure servo valve.

[0074] In summary, the offset working distance of the jet tube 15 is greater than the offset working distance of the jet tube 15 in the existing jet tube pressure servo valve, which can achieve the effect of reducing sensitivity and improving output stability.

[0075] In this embodiment, in the initial state, the jet orifice of the jet tube 15, projected along the jet direction, is tangent to both the fifth receiving hole 165 and the sixth receiving hole 166. The jet tube 15 deflects from left to right, and the line connecting the centers of the fifth and sixth receiving holes 165, 166 is perpendicular to the direction of the jet tube 15's deflection. When the jet tube 15 deflects to the center between the fifth and sixth receiving holes 165, 166, the pressure gain of the receiving holes is zero. The deflection distance of the jet tube 15 is greater than the radius of the jet tube 15. Assuming the jet orifice and receiving holes of the jet tube 15 are the same size, the deflection working distance of the jet tube 15 in this embodiment is greater than that of existing jet tube pressure servo valves, thereby reducing sensitivity and improving output stability.

[0076] Example 4

[0077] Combined with attachment Figure 12 Compared with the third embodiment, the difference of this embodiment is that at any moment during the displacement of the jet tube 15, S5 <S6。

[0078] Specifically, initially, when projected along the jet direction, the areas facing the jet orifice of jet tube 15 and the fifth and sixth receiving holes 165, 166 are both zero. The jet orifices of jet tube 15 are both tangent to the left sides of the fifth and sixth receiving holes 165, 166, and the jet tube 15 is offset from left to right. In this embodiment, the positions of the fifth and sixth receiving holes 165, 166 are offset. During the offset process of jet tube 15, the jet orifice of jet tube 15 is moved closer to the sixth receiving hole 166, and the incremental area of ​​the sixth receiving hole 166 facing the jet orifice of jet tube 15 is greater than the incremental area of ​​the fifth receiving hole 165 facing the jet orifice of jet tube 15. This ensures that the area facing the jet orifice of jet tube 15 by the sixth receiving hole 166 is greater than the area facing the jet orifice of jet tube 15 by the fifth receiving hole 165. Specifically, the line connecting the centers of the fifth and sixth receiving holes 165, 166 is not perpendicular to the offset direction of jet tube 15.

[0079] In this embodiment, the radius of the jet orifice of the jet tube 15 is r, and the radii of the fifth receiving hole 165 and the sixth receiving hole 166 are both R, where R>r. The angle between the line connecting the center of the jet orifice of the jet tube 15 and the center of the sixth receiving hole 166 and the offset direction of the jet tube 15 is α, and the angle between the line connecting the center of the jet orifice of the jet tube 15 and the center of the fifth receiving hole 165 and the offset direction of the jet tube 15 is β, where β>α.

[0080] To ensure that the current received by the torque motor 19 remains proportional to the jet pressure received by the receiving hole, the area directly opposite the jet orifice of the jet tube 15, between the fifth and sixth receiving holes 165 and 166, must continue to increase as the jet tube 15 deflects from left to right. It should be noted that when the area directly opposite the receiving holes decreases during the deflection of the jet tube 15 from left to right, the current received by the torque motor 19 becomes inversely proportional to the jet pressure received by the receiving holes, thus exceeding the operating range of the jet tube 15's deflection.

[0081] Specifically, when the jet tube 15 is offset to the right by a distance of (R+r)cosα, the area of ​​the jet opening of the jet tube 15 facing the sixth receiving hole 166 is maximized. At this time, the effective offset stroke of the jet tube 15 for the sixth receiving hole 166 is (R+r)cosα. When the jet tube 15 is offset to the right by a distance of (R+r)cosβ, the area of ​​the jet opening of the jet tube 15 facing the fifth receiving hole 165 is maximized. At this time, the effective offset stroke of the jet tube 15 for the fifth receiving hole 165 is (R+r)cosβ. Since β>α, cosα>cosβ, and therefore the effective offset stroke of the jet tube 15 is (R+r)cosβ.

[0082] In summary, to reduce the sensitivity of the relative position change between the jet tube 15 and the receiver 16 to the change in the servo valve output pressure and improve the output stability and reliability of the servo valve, the effective displacement stroke of the jet tube 15 must be (R + r) cos α greater than r, that is, R cos α / (1 - cos α) > r.

[0083] Of course, the position and shape of the fifth receiving hole 165 and the sixth receiving hole 166 and the shape of the jet outlet of the jet tube 15 can be set in other ways to ensure that at any moment during the displacement of the jet tube 15, the area facing each other between the jet outlet of the jet tube 15 and the sixth receiving hole 166 is larger than the area facing each other between the jet outlet of the jet tube 15 and the fifth receiving hole 165, thereby ensuring that at any moment during the displacement of the jet tube 15, the jet pressure in the sixth receiving hole 166 is greater than the jet pressure in the fifth receiving hole 165.

[0084] In further settings, as shown in the attached Figure 2 , Attachment Figure 8 As shown, in any of the first to fourth embodiments, a feedback channel 105 is connected between the load port 103 and the fourth cavity 132. The main valve core 133 partially extends into the feedback channel 105, separating the fourth cavity 132 from the feedback channel 105. Furthermore, projected along the sliding direction of the main valve core 133, the cross-section of the feedback channel 105 is smaller than the cross-section of the third cavity 131, so that the force exerted on the main valve core 133 by the jet pressure is greater than the force exerted on the main valve core 133 by the output pressure at the load port 103.

[0085] When the current signal received by the torque motor 19 is larger, the jet tube 15 deflects more, and the jet pressure exerts a greater leftward force on the main valve core 133. At this time, the load port 103 is opened more widely, and the output pressure at the load port 103 increases. The output pressure at the load port 103 is fed back to the left end of the main valve core 133 via the feedback channel 105 as part of the back pressure of the main valve core 133.

[0086] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0087] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0088] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A jet tube servo valve with a low feedback pressure structure, characterized in that: include: A valve body (10), wherein the valve body (10) is provided with a jet space (11), a pilot valve core cavity (12) and a main valve core cavity (13); a pilot valve core (123) is slidably provided in the pilot valve core cavity (12); a first elastic member (124) is connected between the pilot valve core (123) and the side wall of the pilot valve core cavity (12); a main valve core (133) is slidably provided in the main valve core cavity (13); a second elastic member (134) is connected between the main valve core (133) and the side wall of the main valve core cavity (13); A jet amplifier (14), the jet amplifier (14) comprising a jet tube (15) located in the jet space (11) and a receiver (16) for receiving jet liquid, the receiver (16) having a first group of receiving holes (16a) and a second group of receiving holes (16b), the first group of receiving holes (16a) being in communication with the pilot valve core chamber (12), and the second group of receiving holes (16b) being in communication with the main valve core chamber (13); Along the jet direction of the jet tube (15), the distance between the jet outlet of the jet tube (15) and the first group of receiving holes (16a) is d1, and the distance between the jet outlet of the jet tube (15) and the second group of receiving holes (16b) is d2, wherein: d1>d2.

2. The jet tube servo valve with low feedback pressure structure according to claim 1, characterized in that: The pilot valve core (123) divides the pilot valve core cavity (12) into a first cavity (121) and a second cavity (122) which are not connected to each other, and the first elastic member (124) is connected between the pilot valve core (123) and the side wall of the first cavity (121) and / or the second cavity (122); the main valve core (133) divides the main valve core cavity (13) into a third cavity (131) and a fourth cavity (132) which are not connected to each other, and the second elastic member (134) is connected between the main valve core (133) and the side wall of the third cavity (131) and / or the fourth cavity (132); The first group of receiving holes (16a) comprises a first receiving hole (161) and a second receiving hole (162) distributed along the offset direction of the jet tube (15); the first receiving hole (161) is connected to the first cavity (121), and the second receiving hole (162) is connected to the second cavity (122); the second group of receiving holes (16b) comprises a third receiving hole (163) and a fourth receiving hole (164) distributed along the offset direction of the jet tube (15); the third receiving hole (163) is connected to the third cavity (131), and the fourth receiving hole (164) is connected to the fourth cavity (132).

3. The jet tube servo valve with low feedback pressure structure according to claim 2, characterized in that: Projected along the jet direction of the jet pipe (15), the area of the first receiving hole (161) facing the jet orifice of the jet pipe (15) is S1, the area of the second receiving hole (162) facing the jet orifice of the jet pipe (15) is S2, the area of the third receiving hole (163) facing the jet orifice of the jet pipe (15) is S3, and the area of the fourth receiving hole (164) facing the jet orifice of the jet pipe (15) is S4. At any moment during the offset process of the jet pipe (15), S1 ≤ S3 and S2 ≤ S4.

4. The jet tube servo valve with low feedback pressure structure according to claim 3, characterized in that: At any moment during the offset process of the jet pipe (15), S1 < S3 and S2 < S4.

5. The jet tube servo valve with low feedback pressure structure according to claim 1, characterized in that: The pilot spool (123) divides the pilot spool cavity (12) into a non-communicating first cavity (121) and second cavity (122). A first elastic member (124) is connected between the pilot spool (123) and the side walls of the first cavity (121) and / or the second cavity (122); the main spool (133) divides the main spool cavity (13) into a non-communicating third cavity (131) and fourth cavity (132). A second elastic member (134) is connected between the main spool (133) and the side walls of the third cavity (131) and / or the fourth cavity (132); The first group of receiving holes (16a) includes a fifth receiving hole (165), and the fifth receiving hole (165) communicates with the first cavity (121); the second group of receiving holes (16b) includes a sixth receiving hole (166), and the sixth receiving hole (166) communicates with the third cavity (131); The valve body (10) has a return port (104), and both the second cavity (122) and the fourth cavity (132) communicate with the return port (104).

6. The jet tube servo valve with low feedback pressure structure according to claim 5, characterized in that: Projected along the jet direction of the jet pipe (15), the area of the fifth receiving hole (165) facing the jet orifice of the jet pipe (15) is S5, and the area of the sixth receiving hole (166) facing the jet orifice of the jet pipe (15) is S6. At any moment during the offset process of the jet pipe (15), S5 ≤ S6.

7. The jet tube servo valve with low feedback pressure structure according to claim 6, characterized in that: Projected along the jet direction of the jet pipe (15), during the offset process of the jet pipe (15), the fifth receiving hole (165) and the sixth receiving hole (166) start to overlap with the jet orifice of the jet pipe (15) simultaneously.

8. The jet tube servo valve with low feedback pressure structure according to claim 2 or 5, characterized in that: The valve body (10) is also provided with a load port (103). A feedback channel (105) is connected between the load port (103) and the fourth cavity (132). The main spool (133) partially extends into the feedback channel (105) and divides the fourth cavity (132) from the feedback channel (105).

9. The jet tube servo valve with low feedback pressure structure according to claim 8, characterized in that: Projected along the sliding direction of the main valve core (133), the cross-section of the feedback channel (105) is smaller than the cross-section of the third cavity (131), so that the force exerted by the jet pressure on the main valve core (133) is greater than the force exerted by the output pressure at the load port (103) on the main valve core (133).

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