CN108561593A - Pneumatic relay - Google Patents

Abstract

The invention relates to a pneumatic relay, which includes a base pressure body and a back pressure body. The back pressure housing has built-in threads. The back pressure housing moves axially, and is fixed with a set screw after the movement is completed; the tail of the intake valve core of the relay grows to form a tail straight shank section, and the tail straight shank section is inserted into the assembly formed by the pressure ring and the guide sleeve, and then acts as A whole is installed in the intake valve seat; the center of the intake valve core and the exhaust valve core of the relay is provided with a through hole, which is connected with the central through hole of the diaphragm seat of the relay to form an exhaust channel. The air channel is provided with a conduction hole to communicate with the output cavity of the relay. In the present invention, the intake valve seat can be moved axially, the length of the valve core can be adjusted relatively, and the effective working area of the intake valve core is small, so that the output hysteresis is reduced and the sudden jump that occurs when the two working conditions transition The value decreases, the insensitive area narrows, and the leakage flow balance point is far away from the working range of the relay.

Description

pneumatic relay

technical field

The invention relates to the technical field, in particular to a pneumatic relay.

Background technique

Pneumatic relays provide high-precision controlled air sources for pneumatic instruments. The output accuracy of pneumatic relays determines the working accuracy of pneumatic instruments. The dynamic characteristics of pneumatic relays directly affect the stability of pneumatic instruments. The relay shown in Figure 1 is a commonly used relay in China. As shown in Figure 2, when the back pressure Pn increases, the output pressure P+ 0=f(Pn) increases accordingly, and when the back pressure Pn decreases, the output pressure P- 0= f(Pn) decreases accordingly. To ensure that P+ 0=P- 0 under the specified back pressure Pn (that is, △P ₀ ≈ 0), it must be strictly guaranteed that when the diaphragm seat 15 moves toward the diaphragm 14, The effective working area of 16 is equal to the effective working area of the diaphragms 14 and 16 after the movement. Due to several factors such as manufacturing and assembly, △P ₀ ≠ 0, △P ₀ is the hysteresis at this specified point. After assembly, the diaphragms 14, 16 are inside the housing, and their position and state cannot be detected. Manufacturing errors, assembly errors, and even the degree of clamping of the fastening screws will affect the position and state of the diaphragms 14, 16, that is, directly affect the diaphragm 14. , 16 effective working area, so the return difference is uncontrollable and large. The work of the pneumatic relay is a process of dynamic balance in which two working conditions alternate. The first working condition is that the intake valve is opened and the exhaust valve is closed. The second working condition is that the intake valve is closed and the exhaust valve is opened. The output equation subtraction of working conditions is:

△P ₀ ≈(△P ₀ *A _input +T _bullet )/(A _output -A _input ) …………(1)

△P ₀ —Sudden value of output pressure (also known as: rotation control error)

Ps—gas source pressure

A _into - the effective area of the intake spool

T _bomb - spring force

A _output - the effective area of the output cavity

△P ₀ is the mutation value of the output pressure in the transition between the two working conditions, which is extremely unfavorable to the output characteristics of the relay. From the above formula, it can be known that _reducing Ain will reduce △P ₀ , and the effective area _Ain of the input spool shown in Figure 1 may decrease very little, and its rotational control error is relatively large, and the output characteristics are poor. It can be seen from Figure 2 that there is an insensitive zone between the first working condition and the second working condition of the relay, and in this zone for a Pn value, the output pressure _P0 value is uncertain, which affects the relay characteristics are extremely unfavorable.

When the relay is in a balanced state, the output flow is zero, and the relay can also be in the first working state, the second working state or the alternate working state of the two working conditions due to the difference in the leakage of the intake valve and the exhaust valve. When the output pressure increases, the pressure difference at both ends of the intake spool decreases, and the leakage decreases, while the pressure at both ends of the exhaust spool increases, and the leakage increases. The curve of leakage Q and output pressure is shown in Figure 6. These two curves have a Intersection point E, the corresponding output pressure P _E , at this point the leakage Q of the intake valve and the exhaust valve are equal, and the vicinity of this point is the transition zone between the two working conditions, in which the output pressure change is insensitive and unresponsive, The return difference is large, and the output pressure may change suddenly. To solve this problem: one is to reduce the width of the insensitive zone, and the other is to control the P _E point not to appear within the working range of the relay. According to the above formula (1) and Figure 6, it can be seen that reducing the insensitive area requires reducing the effective area A of the intake spool, and controlling the P _{E position} requires controlling the leakage of the two spools. These two measures are shown in Figure 1 None of the structures shown can be realized. Gas source P _S is unstable and fluctuates △ _PS leading to output pressure Po change △P ₀ , and the fluctuation of gas source is substituted into the output equation of the first working condition to organize and compare:

△P ₀ /△P _S =—A input/(A output-A input) ………（2）

It can be seen from formula (2) that the output pressure is affected by the effective _area A of the intake valve core. The larger the A _is , the greater the impact of the air source fluctuation is, and the structure of the valve core shown in Figure 1 should reduce A _Advancement is very limited.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a pneumatic relay with small hysteresis and dead zone error and stable dynamic characteristics. It is used to solve the problem of output hysteresis caused by the difference between the effective area of the relay diaphragm seat moving to the left and the effective area after moving to the right, and the effective area of the intake valve core of the relay. The area is large, the jump value is large and the insensitive area is large when the two working conditions transition, and the impact of input gas source pressure fluctuations on the output pressure is reduced, and the leakage flow balance point is controlled when the output flow is zero. Relay operating range.

The purpose of the present invention is achieved through the following technical solutions:

A pneumatic relay, which includes two parts: a base pressure body and a back pressure body:

The back pressure housing of the back pressure body has a built-in thread, and the intake valve seat of the relay is screwed into the back pressure housing in a threaded manner, so that the intake valve seat can move axially in the back pressure housing. After the movement is completed Fix with end set screws;

The tail of the intake valve core of the relay grows to form a tail straight handle section, and the tail straight handle section is inserted into the assembly formed by the pressure ring and the guide sleeve, and then installed in the intake valve seat as a whole;

The center of the intake valve core and the exhaust valve core of the relay is provided with a through hole, which is connected with the central through hole of the diaphragm seat of the relay to form an exhaust passage, and the exhaust passage is provided with a conduction hole Conducted with the output cavity of the relay.

As a further improvement of this solution, the relay specifically includes an intake valve core, an exhaust valve core, a sealing seat, a diaphragm pressure plate, a diaphragm seat, an exhaust ring, a back pressure housing, a diaphragm A, a diaphragm Seat, base pressure housing, diaphragm B, intake valve seat; the back pressure housing and the base pressure housing are docked to form a cavity, and the other end of the base pressure housing is designed with an air source pressure input port;

The sealing seat is fixed in the back pressure housing, the front end of the diaphragm seat is installed in the sealing seat and extends into the back pressure housing, the end of the diaphragm seat is located in the cavity formed by the back pressure housing and the base pressure housing, The diaphragm pressing plate is installed at the end of the diaphragm seat, diaphragm A and diaphragm B are installed on the diaphragm pressing plate, a ring of partitions is arranged between the diaphragm A and diaphragm B, and the exhaust ring is sleeved on Diaphragm pressure plate between diaphragm A and diaphragm B;

A back pressure cavity is formed between the diaphragm A, the back pressure housing and the sealing seat;

An exhaust cavity is formed between the diaphragm A, the diaphragm B, the exhaust ring and the separator;

A base pressure cavity is formed between the diaphragm B, the diaphragm pressure plate and the base pressure housing;

An output cavity is formed between the intake valve seat, the exhaust valve core, the diaphragm seat and the sealing seat, and a through hole is set in the output cavity for outputting the output pressure of the amplifier;

An air intake cavity is formed between the intake valve seat, the intake valve core, the back pressure housing and the retaining ring, and the intake cavity is provided with a through hole for inputting the pressure of the air source.

As a further improvement of this solution, a return spring is also included, and the intake valve core, exhaust valve core, return spring, pressure ring, guide sleeve, and retaining ring are sequentially loaded into the intake valve seat.

As a further improvement of this solution, a sealing ring A is installed between the sealing seat and the back pressure housing, and a sealing ring B is installed between the sealing seat and the diaphragm seat;

A sealing ring C and a sealing ring D are respectively installed between the front and rear ends of the intake valve seat and the back pressure housing;

A seal ring E is installed between the guide sleeve and the intake valve seat, and a seal ring F is installed between the guide sleeve and the intake valve seat.

As a further improvement of this solution, the outer wall of the intake valve seat is provided with two outer circular grooves, and the sealing ring C and the sealing ring D are respectively located in the outer circular grooves.

The beneficial effects of the present invention are: by adjusting the intake valve seat, the exhaust valve core moves axially to change the relative length of the exhaust valve core, and the effective working area becomes a controllable parameter. According to the system balance relationship, the hysteresis It will also be restrained to a certain extent. In the design, the sealing specific pressure of the intake valve core is maintained, and the diameter of the straight shank section at the tail of the intake valve core is increased, which can greatly reduce the effective working area of the intake valve core, making the jump value, insensitive area and gas The influence of the source pressure fluctuation on the output pressure will be improved, and the improvement of the static characteristics, dynamic characteristics and leakage flow balance point only depends on the low-cost realization of the relative length of the spool and the reduction of the area of the intake spool. , reduces the processing accuracy of related parts, greatly reduces the assembly labor, so the industrial benefits brought by the present invention are relatively large.

Description of drawings

Fig. 1 is the structural schematic diagram of prior art relay;

Figure 2 is the theoretical operating characteristic curve of the relay;

Fig. 3 is the structural representation of embodiment 1;

Fig. 4 is the structural representation of embodiment 2;

Fig. 5 is a schematic diagram of the change law of the effective working area when the diaphragm moves;

Figure 6 is the leakage flow characteristic curve when the relay is balanced;

Fig. 7 is the single-acting structure schematic diagram of embodiment 3;

Fig. 8 is a schematic diagram of the double-acting mechanism of Embodiment 3.

In the picture:

Ps-air source pressure, Pn-control pressure, Po-amplifier output pressure;

P _E - the output pressure corresponding to the intersection of the intake valve leakage flow curve and the exhaust valve leakage flow curve;

△Po-the mutation value of the output pressure (also known as: the control error), △Pn-the width of the insensitive area;

A _inlet - the effective area of the intake spool, T _spring - the spring force, A _output - the effective area of the output cavity;

In Figure 1: 10-return spring, 11-intake valve core, 12-exhaust valve core, 13-exhaust hole, 14-diaphragm A, 15-diaphragm seat, 16-diaphragm B, 17-input Chamber, 18-output chamber, 19-exhaust chamber, 20-reference pressure chamber, 21-back pressure chamber.

In Fig. 3 and Fig. 4: 30-intake valve core, 31-exhaust valve core, 32-sealing seat, 33-diaphragm pressure plate, 34-exhaust ring, 35-back pressure housing, 36-diaphragm A , 37-partition, 38-diaphragm seat, 39-base pressure housing, 40-diaphragm B, 59-base pressure chamber, 60-exhaust chamber, 61-back pressure chamber, 62-sealing ring A, 63 -Sealing ring B, 64-Output chamber, 65-Sealing ring C, 66-Through hole, 67-Intake cavity, 68-Sealing ring D, 69-Exhaust channel, 0-Sealing ring E, 71-Sealing ring F, 72-set screw, 73-retaining ring, 74-pressure ring, 75-guiding sleeve, 76-intake valve seat, 77-return spring, L-tail straight handle section.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with specific examples, but the protection scope of the present invention is not limited to the following description.

Example 1

As shown in Figure 3, a pneumatic relay includes two parts: a base pressure body and a back pressure body: the back pressure housing 35 of the back pressure body has built-in threads, and the intake valve seat 76 of the relay is The threaded connection is screwed into the back pressure housing 35, so that the intake valve seat 76 can move axially in the back pressure housing 35. After the movement is completed, it is fixed with the set screw 72; the tail of the intake valve core 30 of the relay The straight shank section L at the tail is formed by growing, and the straight shank section L at the tail is inserted into the assembly formed by the pressure ring 74 and the guide sleeve 75, and then installed in the intake valve seat 76 as a whole; the row of the intake valve core 30 and the relay The center of the air valve core 31 is provided with a through hole, which is connected with the through hole in the center of the diaphragm seat 38 of the relay to form an exhaust channel 69, and the exhaust channel 69 is provided with a conduction hole 66 to lead to the output chamber 64 of the relay. Pass. Preferably, the intake valve core 30 and the exhaust valve core 31 are integrally formed as a whole, and the set screw 72 is arranged on the outer end surface of the back pressure housing 35 .

In order to make the description of this embodiment more detailed, this embodiment will make a specific description of the structure of the relay. In addition to the above-mentioned improvements, the rest of the relay used in this program can use the relay of the prior art. Structure.

As shown in Figure 3, the relay specifically includes an intake valve core 30, an exhaust valve core 31, a sealing seat 32, a diaphragm pressure plate 33, a diaphragm seat 38, an exhaust ring 34, a back pressure housing 35, a diaphragm A36, diaphragm seat 38, base pressure housing 39, diaphragm B40, intake valve seat 76; the back pressure housing 35 and the base pressure housing 39 are butted to form a cavity, and the other end of the base pressure housing 39 is designed with an air source pressure input port; the sealing seat 32 is fixed in the back pressure housing 35, the front end of the diaphragm seat 38 is installed in the sealing seat 32 and extends into the back pressure housing 35, and the end of the diaphragm seat 38 is located between the back pressure housing 35 and In the cavity formed by the base pressure housing 39, the diaphragm holding plate 33 is installed at the end of the diaphragm seat 38, the diaphragm A36 and the diaphragm B40 are installed on the diaphragm holding plate 33, and a ring spacer is arranged between the diaphragm A36 and the diaphragm B40. The plate 37 and the exhaust ring 34 are sleeved on the diaphragm pressure plate 33 between the diaphragm A36 and the diaphragm B40.

A back pressure cavity 61 is formed between the diaphragm A36, the back pressure housing 35 and the sealing seat 32;

An exhaust cavity 60 is formed between the diaphragm A36, the diaphragm B40, the exhaust ring 34, and the separator 37;

A base pressure cavity 59 is formed between the diaphragm B40, the diaphragm pressure plate 33 and the base pressure housing 39;

An output cavity 64 is formed between the intake valve seat 76, the exhaust valve core 31, the diaphragm seat 38 and the sealing seat 32, and the output cavity 64 has a through hole for outputting the output pressure of the amplifier;

An intake cavity 67 is formed between the intake valve seat 76 , the intake valve core 30 , the back pressure housing 35 and the retaining ring 73 , and the intake cavity 67 is provided with a through hole for inputting the pressure of the gas source.

As a further improvement of this embodiment, in order to realize the adjustment of the intake valve core 30 and the exhaust valve core 31, a return spring 77, the intake valve core 30, the exhaust valve core 31, the return spring 77, and the pressure ring 74 are also included. , guide sleeve 75, back-up ring 73 are packed into intake valve seat 76 successively. Finally, in order to enhance air tightness, a sealing ring A62 is installed between the sealing seat 32 and the back pressure housing 35, and a sealing ring B63 is installed between the sealing seat 32 and the diaphragm seat 38; A seal ring C65 and a seal ring D68 are respectively installed between the pressure housing 35; a seal ring E70 is installed between the guide sleeve 75 and the intake valve seat 76, and a seal ring F71 is installed between the guide sleeve 75 and the intake valve seat 76 As a further improvement of this solution, the outer wall of the intake valve seat 76 is provided with two outer circular grooves, and the sealing ring C65 and the sealing ring D68 are respectively located in the outer circular grooves.

Example 2

As shown in Figure 4, a pneumatic relay includes two parts: a base pressure body and a back pressure body: the back pressure housing 35 of the back pressure body has a built-in thread, and the intake valve seat 76 of the relay is The threaded connection is screwed into the back pressure housing 35, so that the intake valve seat 76 can move axially in the back pressure housing 35. After the movement is completed, it is fixed with the set screw 72; the tail of the intake valve core 30 of the relay The straight shank section L at the tail is formed by growing, and the straight shank section L at the tail is inserted into the assembly formed by the pressure ring 74 and the guide sleeve 75, and then installed in the intake valve seat 76 as a whole; the row of the intake valve core 30 and the relay The center of the air valve core 31 is provided with a through hole, which is connected with the through hole in the center of the diaphragm seat 38 of the relay to form an exhaust channel 69, and the exhaust channel 69 is provided with a conduction hole 66 to lead to the output chamber 64 of the relay. Pass. Preferably, the intake valve core 30 and the exhaust valve core 31 are integrally formed as a whole, and the set screw 72 is arranged on the outer end surface of the back pressure housing 35 .

Compared with embodiment 1, the difference of this embodiment lies in the design of the base pressure body, as shown in Figure 3, the output form of the relay in embodiment 1 is a single output relay, in this embodiment select It is a dual-output relay. It can be seen from FIG. 4 that the back pressure housing 35 and the base pressure housing 39 in this embodiment are identical, and their internal structures are also identical.

Example 3

As shown in Fig. 7 and Fig. 8, adjust the Ps gas path on the upper part of the base pressure shell, and the gas source directly enters the working chamber 60, so that the working chamber 60 is used as the base pressure chamber, and the working chamber 59 is used as the evacuation chamber. The involved structure does not change.

Description of working principle:

When the position of the diaphragm is manufactured and assembled, the results are not ideal. At the same time, it can be seen from Figure 5 that the diaphragm has different equivalent diameters, that is, different effective working areas, in different positions. By adjusting the intake valve seat 76, the exhaust valve core 31 moves axially to change the relative length of the exhaust valve core 31, and the effective working area becomes a controllable parameter. suppression. In the design, the sealing specific pressure of the intake valve core is maintained, and the diameter of the straight handle section at the tail of the intake valve core is increased, which can greatly reduce the effective working _area A of the intake valve core, so that the sudden jump value △Po, The influence of the sensitive area △Pn and the fluctuation of air source pressure on the output pressure will be improved.

When the output flow rate is zero, the leakage flow rate of the intake valve core and the exhaust valve core is shown in Figure 6. Adjust the intake valve seat 76 slightly to change the leakage amount, so that the working range of the relay is on the side or side of the P _E point , effectively away from the PE _point region.

For example, adjust the movement of the intake valve seat, the leakage of the intake valve core 30 increases, and the leakage of the exhaust valve core 31 decreases, the relay will work in the second working condition, and the working range is at the side _PD of _PE .

For example, adjust the movement of the intake valve seat, the leakage of the intake valve core 30 decreases, and the leakage of the exhaust valve core 31 increases, the relay will work in the first working condition, and the working range is at the side _PF of _PE .

A conduction hole 66 is set on the exhaust passage 69 to communicate with the output cavity, so that the relay has a constant leakage flow equivalent to the leakage of the exhaust valve core, and the relay will always work in the first working condition. The range is fixed at point P _F on the side of point _PE .

After using this scheme, the effective working area A _{is further} reduced, and the range of P _{and E} points is narrowed, which provides conditions for micro-adjustment of the intake valve seat.

The above descriptions are only preferred embodiments of the present invention, and it should be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and Modifications can be made within the scope of the ideas described herein, by virtue of the above teachings or skill or knowledge in the relevant art. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (5)

1. a kind of pneumatic relay, which includes base laminate and back pressure body two parts, it is characterised in that：

The back pressure shell of the back pressure body（35）Disposed thread, the inlet valve seat of relay（76）The mode of being threadedly coupled screws in the back of the body Pressure shell body（35）It is interior so that inlet valve seat（76）It can be in back pressure shell（35）Interior axial movement uses holding screw after the completion of mobile （72）It is fixed；

The air inlet spool of the relay（30）Tail portion increases to form tail portion straight handle section（L）, the tail portion straight handle section（L）Be inserted by Pressure ring（74）And guide sleeve（75）Then the component of formation is mounted on inlet valve seat as a whole（76）It is interior；

The air inlet spool（30）With the exhaust plug of relay（31）It is integrally formed as a whole, it is centrally disposed logical The diaphragm seat of hole, the through-hole and relay（38）Central through hole docks to form exhaust passage（69）, the exhaust passage（69）It opens If via hole（66）With the output cavity of relay（64）Conducting.

2. pneumatic relay according to claim 1, which is characterized in that the relay specifically includes air inlet spool （30）, exhaust plug（31）, seal receptacle（32）, diaphragm pressing plate（33）, diaphragm seat（38）, air exhaust loop（34）, back pressure shell（35）、 Diaphragm A（36）, diaphragm seat（38）, base pressure shell body（39）, diaphragm B（40）, inlet valve seat（76）；The back pressure shell（35）And base Pressure shell body（39）Dock and formed cavity, base pressure shell body（39）The other end is designed with bleed pressure input port；

The seal receptacle（32）It is fixed on back pressure shell（35）It is interior, the diaphragm seat（38）Front end is mounted on seal receptacle（32）Inside simultaneously Stretch into back pressure shell（35）It is interior, diaphragm seat（38）End is located at back pressure shell（35）With base pressure shell body（39）In the cavity of formation, The diaphragm pressing plate（33）Mounted on diaphragm seat（38）End, diaphragm pressing plate（33）Upper installation diaphragm A（36）With diaphragm B（40）, The diaphragm A（36）With diaphragm B（40）Between be provided with a circle partition board（37）, the air exhaust loop（34）It is socketed in diaphragm A（36） With diaphragm B（40）Between diaphragm pressing plate（33）On；

The diaphragm A（36）, back pressure shell（35）, seal receptacle（32）Between form back pressure cavity（61）；

The diaphragm A（36）, diaphragm B（40）, air exhaust loop（34）, partition board（37）Between form evacuation chamber（60）；

The diaphragm B（40）, diaphragm pressing plate（33）, base pressure shell body（39）Between formed base press chamber（59）；

The inlet valve seat（76）, exhaust plug（31）, diaphragm seat（38）, seal receptacle（32）Between form output cavity（64）, should Output cavity（64）Through-hole is opened up for output amplifier output pressure；

The inlet valve seat（76）, air inlet spool（30）, back pressure shell（35）, baffle ring（73）Between form inlet chamber（67）, should Inlet chamber（67）Offer the through-hole for inputting bleed pressure.

3. pneumatic relay according to claim 2, which is characterized in that further include resetting spring（77）, the intake valve Core（30）, exhaust plug（31）, resetting spring（77）, pressure ring（74）, guide sleeve（75）, baffle ring（73）It is sequentially loaded into inlet valve seat （76）.

4. pneumatic relay according to claim 3, which is characterized in that the seal receptacle（32）With back pressure shell（35）It Between sealing ring A is installed（62）, seal receptacle（32）With diaphragm seat（38）Between sealing ring B is installed（63）；

The inlet valve seat（76）Rear and front end and back pressure shell（35）Between be separately installed with sealing ring C（65）With sealing ring D （68）；

The guide sleeve（75）With inlet valve seat（76）Between sealing ring E is installed（70）, guide sleeve（75）With inlet valve seat （76）Between sealing ring F is installed（71）.

5. pneumatic relay according to claim 4, which is characterized in that the inlet valve seat（76）Outer wall is provided with twice Peripheral groove, the sealing ring C（65）With sealing ring D（68）It is located in peripheral groove.