pressure switch

Abstract

The application provides a pressure switch. The shell has a first radial step structure, a second radial step structure and a shell handle; the push sleeve is installed in the shell cavity and has a third radial step structure; the first elastic member is installed between the first radial step structure and the third radial step structure; the mounting seat is installed at the second opening end of the shell, a cavity is formed between the mounting seat and the push sleeve, and the second elastic member is installed in the cavity; the second elastic member is a pagoda type spring; the dead zone adjusting screw is installed in the bolt channel of the mounting seat, the dead zone adjusting screw is in contact with the second elastic member, and the compression amount of the second elastic member can be adjusted; the third elastic member is installed in the push sleeve cavity, and the compression amount of the third elastic member can be adjusted through the set value adjusting screw. Based on the characteristics of the variable stiffness elastic element, the second elastic element with adjustable stiffness is introduced, so that the dead zone of the pressure switch is adjustable, and the pressure switch has the advantages of high precision, long service life, high action frequency and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure system control elements, and relates to a pressure switch, in particular to a dead zone adjustable pressure switch. BACKGROUND

[0002] The pressure switch is a component for pressure monitoring, alarming or control, which is used for breaking or closing the circuit with the change of pressure, and is mainly composed of a gas pressure sensing element, an elastic element, an adjusting structure and a switch device. The dead zone is the pressure difference between the upper switching value and the lower switching value of the pressure switch, and can be divided into a dead zone fixed pressure switch and a dead zone adjustable pressure switch according to whether the dead zone is adjustable. Compared with the dead zone adjustable pressure switch, the dead zone of the dead zone fixed pressure switch is fixed, and the dead zone is relatively small and has large consistency difference, and usually only the upper switching value or the lower switching value can be used, and the upper switching value and the lower switching value cannot be used at the same time.

[0003] The influencing factors of the dead zone of the pressure switch include the effective action area of the pressure, the pressure sensing mode, the stiffness of the elastic element and the differential travel of the switch device. Since the effective action area of the pressure and the pressure sensing mode are difficult to change, if the dead zone of the pressure switch is to be adjusted arbitrarily, the general measure is to introduce other external force within the differential travel range of the switch device and change the size to obtain different equivalent stiffness of the elastic element. However, since the differential travel of the switch device is usually very small and cannot be directly used, the differential travel of the switch device needs to be amplified through the principle of the lever, and then the volume of the dead zone adjustable pressure switch is generally larger, which is 4 times the volume of the same performance dead zone fixed pressure switch. For example, most of the dead zone adjustable pressure switches manufactured in China and the main brands of pressure switches such as Condor and Eaton abroad. In addition, the switch device is made into an open type, and the gap between the contacts is adjusted by a screw to change the differential travel of the micro switch, which is also an important way to obtain the size adjustment of the dead zone of the pressure switch. However, the volume is generally more than 2 times the volume of the same performance dead zone fixed pressure switch, such as the Sanwa brand pressure switch used in the market.

[0004] In the field of rail transit, based on the requirements of the use scene, it is usually necessary to use the upper switching value and the lower switching value of the pressure switch at the same time. However, since the existing dead zone adjustable pressure switch has a large volume, a large installation space is required, and sometimes two dead zone fixed pressure switches have to be used instead of one dead zone adjustable pressure switch, which is inconvenient to install and use. SUMMARY

[0005] The present application aims at the current situation that the dead zone of the pressure switch is fixed, the dead zone is small and the precision consistency is poor in the prior art, and provides a new type of pressure switch to solve the problem that the dead zone of the pressure switch is not adjustable in the prior art.

[0006] To achieve the above object, the technical scheme adopted by the present application is:

[0007] A pressure switch, comprising:

[0008] The shell is an open structure at both ends, forming a shell cavity, a first radial step structure is formed along the first end opening of the shell cavity, and a second radial step structure is arranged away from the second end of the shell along the first radial step structure, both the first radial step structure and the second radial step structure extend from the inner wall of the first end of the shell to the direction close to the radial center of the shell; a shell handle is formed at the second radial step structure and extends away from the second end of the shell;

[0009] The push sleeve is closed at one end and open at the other end, forming a push sleeve cavity along the closed end to the open end; the closed end of the push sleeve is located on the second end side of the shell, and a third radial step structure is formed along the outer wall of the closed end of the push sleeve and extends away from the radial center of the push sleeve; the open end of the push sleeve extends from the opening of the first radial step structure to the outside of the shell;

[0010] The first elastic member is installed between the third radial step structure and the first radial step structure;

[0011] The mounting seat is installed at the second open end of the shell, and a cavity is formed between the end of the mounting seat facing the closed end of the push sleeve and the closed end of the push sleeve; the mounting seat has a bolt channel penetrating the cavity and the outer wall in the axial direction of the mounting seat; the mounting seat further has a medium passage penetrating the outer wall and the cavity;

[0012] The second elastic member is installed in the cavity formed between the mounting seat and the push sleeve, and the second elastic member is a pagoda-shaped spring;

[0013] The dead zone adjusting screw is installed in the bolt channel and abuts against the second elastic member;

[0014] The third elastic member is installed in the push sleeve cavity, and a spring seat is arranged on the side of the third elastic member facing the first end of the shell;

[0015] The set value adjusting screw is installed in the screw hole of the shell handle and abuts against the spring seat.

[0016] In some embodiments of the present application, one end of the second elastic member with a smaller radial width abuts against the dead zone adjusting screw.

[0017] In some embodiments of the present application, a clamping groove is formed on the side of the dead zone adjusting screw abutting against the second elastic member, and the end of the second elastic member is located in the clamping groove.

[0018] In some embodiments of the present application, a fine adjustment nut is further included, which is installed at the open end of the push sleeve and is threadedly connected with the push sleeve; the fine adjustment nut has an axial through hole, and the set value adjusting screw is threadedly connected with the through hole.

[0019] In some embodiments of the present application, a micro switch is further included, which is installed on the side wall of the handle of the shell;

[0020] An opening is formed between the second radial step structure and the first radial step structure, and the contact button of the micro switch is located in the opening and in contact with the fine adjustment nut.

[0021] In some embodiments of the present application, an annular opening is formed at one end of the mounting seat towards the push sleeve, and a fourth step structure is formed along the edge of the annular opening; a medium through groove or a medium through hole is formed along the edge of the fourth step structure.

[0022] In some embodiments of the present application, a locking sleeve is further included, which is installed in the cavity of the shell and located between the push sleeve and the shell; the first elastic member is located in the space formed by the locking sleeve and the push sleeve.

[0023] In some embodiments of the present application, the first elastic member is an elastic bellows.

[0024] In some embodiments of the present application, a fixing ring is further included, which is located in the gap between the push sleeve and the shell; one end of the first elastic member is connected with the third radial step structure, and the other end is installed with the fixing ring.

[0025] In some embodiments of the present application, the following sealing structures are further included:

[0026] A first sealing ring is arranged between the outer wall of the mounting seat and the inner wall of the shell;

[0027] A second sealing ring is arranged between the inner wall of the mounting seat and the outer wall of the push sleeve;

[0028] A sealing pad is arranged between the fixing ring and the first radial step structure.

[0029] The dead zone adjustable pressure switch provided by the present application has the following beneficial effects:

[0030] The present application provides a dead zone adjustable pressure switch different from the conventional lever amplification type or open differential stroke adjustable switch device, which is combined with the dead zone adjustment principle of the pressure switch and based on the characteristics of the variable stiffness elastic element. On the basis of maintaining the existing dead zone fixed pressure switch shape structure, a stiffness adjustable dead zone spring (second elastic element) is directly introduced to solve the problems of dead zone fixation, small dead zone and poor precision consistency of the same type of product. By changing the stiffness of the second elastic element, the purpose of adjusting the dead zone is achieved. The contradiction between the size of the pressure switch, the allowable action frequency and the adjustability of the dead zone size is solved. The pressure switch provided by the present application has the same size as the existing dead zone fixed pressure switch, has the advantages of high precision, long service life, high action frequency and the like, and has better comprehensive performance than the conventional dead zone adjustable pressure switch. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0032] Figure 1 It is a schematic diagram of pressure switch structure;

[0033] Figure 2a It is a schematic diagram of the first perspective structure of the shell;

[0034] Figure 2b It is a schematic diagram of the second perspective structure of the shell;

[0035] Figure 3 It is a schematic diagram of the gas pressure sensing element structure;

[0036] Figure 4a It is a schematic diagram of the mounting seat structure;

[0037] Figure 4b It is a schematic diagram of the mounting seat structure;

[0038] Figure 5 It is a whole force analysis diagram of the push sleeve-fine adjustment nut (upper switching state);

[0039] Figure 6 It is a whole force analysis diagram of the push sleeve-fine adjustment nut (lower switching state);

[0040] 1-shell, 101-first radial step structure, 102-second radial step structure, 103-shell handle, 104-opening, 105-cable groove;

[0041] 2-push sleeve, 201-push sleeve cavity, 202-third radial step structure, 203-shoulder structure;

[0042] 3-first elastic member;

[0043] 4-mounting seat, 401-medium passage, 402-bolt channel, 403-sealing ring, 404-fourth step structure, 405-medium slot;

[0044] 5-fixed ring;

[0045] 6-dead zone adjusting bolt;

[0046] 7-second elastic member;

[0047] 8-third elastic member;

[0048] 9-spring seat;

[0049] 10 - set value adjusting screw;

[0050] 11 - fine adjustment nut;

[0051] 12 - micro switch;

[0052] 13 - sealing washer;

[0053] 14 - first sealing ring;

[0054] 15 - second sealing ring;

[0055] 16 - locking sleeve;

[0056] 17 - connector;

[0057] 18 - protective cover;

[0058] 19 - third sealing ring;

[0059] 20 - cable. DETAILED DESCRIPTION

[0060] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0061] It should be noted that when an element is referred to as "being disposed on", "connected to" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0062] It should be understood that the terms "upper", "lower", "radial", "axial" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0063] It should be noted that the terms "first", "second", "third" are only for descriptive purposes and do not imply relative importance.

[0064] The present application provides a pressure switch, the cross-sectional structure of which is referred to as Figure 1 , comprising the following structural units.

[0065] Housing 1: the structure is referred to as Figure 2a and Figure 2b, the whole is asymmetric, and is an open structure at both ends. In the direction shown in the figure, the right side in the axial direction is defined as the first end of the shell, and the left side is defined as the second end of the shell. The first end and the second end of the shell form a shell cavity.

[0066] A first radial step structure 101 is formed along the opening of the first end of the shell cavity. A second radial step structure 102 is arranged away from the second end of the shell along the first radial step structure 101. The first radial step structure 101 and the second radial step structure 102 both extend from the inner wall of the first end of the shell towards the radial center of the shell. A shell handle 103 is formed at the second radial step structure 102 and extends away from the second end of the shell. In this embodiment, the shell handle extends along the axial direction of the shell.

[0067] The first radial step structure 101 is a symmetrical step structure formed along the inner circumferential wall of the shell cavity, and the second radial step structure 102 extends only along the axial outer wall of part of the first radial step structure 101 towards the axial direction of the shell 1. Based on this, an opening 104 is formed between the first radial step structure 101 and the second radial step structure 102.

[0068] The push sleeve 2 is arranged in the shell cavity, one end is closed, and one end is open. A push sleeve cavity 201 is formed along the closed end to the open end. The closed end is located on the second end side of the shell, and a third radial step structure 202 is formed along the outer wall of the closed end and extends away from the radial center of the push sleeve 2. The open end extends from the opening of the first radial step structure 101 to the outside of the shell. The push sleeve 2 and the shell 1 can move relative to each other. During the movement of the push sleeve 2 towards the second radial step structure 102, the push sleeve 2 can be in contact with the second radial step structure 102 and be stopped by the second step mechanism 102. The push sleeve 2 is also an axial asymmetric structure, and one side in contact with the second radial step structure 102 has a longer axial length than the other side.

[0069] The first elastic member 3 is installed between the third radial step structure 202 and the first radial step structure 101. A containing cavity is formed between the first radial step structure 101, the third radial step structure 202, the outer wall of the push sleeve 2 and the inner wall of the shell, and the first elastic member 3 is installed in the containing cavity. In this embodiment, the first elastic member 3 adopts a bellows, which is sleeved on the outer circumference of the push sleeve 3. The stiffness of the bellows is small, and the force generated by the deformation thereof can be ignored. In addition to the bellows, the first elastic member 3 can also adopt other gas pressure sensing modes such as piston type and diaphragm type.

[0070] In some embodiments of the present invention, a retaining ring 5 is further included, located within the gap between the push sleeve 2 and the housing 1; one end of the first elastic member 3 is connected to the third radial step structure 202, and the other end is fitted with the retaining ring 5. Specifically, the bellows is axially expandable and contractible, and its two ends are welded to the push sleeve 2 and the retaining ring 5, respectively. The retaining ring 5 seals the mounting cavity of the first elastic member 3, and also assists in fixing the first elastic member 3, while facilitating the compression of the first elastic member 3. To further improve the sealing effect, a sealing gasket 13 is provided between the retaining ring 5 and the first radial step structure 101.

[0071] Since the first elastic element 3, the pushing sleeve 2, and the fixing ring 5 function as a pneumatic pressure sensor in the entire pressure switch, they are defined as a pneumatic pressure sensing element as a whole. (See structural reference.) Figure 3 The second radial step structure 102 of the housing 1 limits the maximum displacement of the actuating ring of the pneumatic sensing element, preventing damage to the contact button of the micro switch 12 due to over-extrusion.

[0072] Mounting Base 4: Structural Reference Figure 4a and Figure 4b It is installed at the second open end of the housing 1, and a cavity is formed between the end of the push sleeve 2 facing the closed end of the push sleeve 2; along the axial direction of the mounting base 4, it has a bolt channel 402 that penetrates the cavity and the outer wall, and the bolt channel 402 penetrates the outer wall of the cavity and the mounting base 4 in the axial direction and has internal threads.

[0073] In some embodiments of the present invention, to improve sealing performance, a first sealing ring 14 is provided between the outer wall of the mounting base 4 and the inner wall of the housing 1. A second sealing ring 15 is provided between the inner wall of the mounting base 4 and the dead zone adjusting bolt 6.

[0074] The mounting base 4 further has a medium passage 401 that penetrates the outer wall and the cavity. The medium passage 401 is used to fill the pressure switch with a working medium. In this embodiment, the medium can be either a gas or a liquid. In this embodiment, the medium passage 401 is inclined towards the cavity along the radial direction of the outer wall of the mounting base 4. The opening of the medium passage 401 is located on the radial direction of the outer wall of the mounting base, and a sealing ring 403 is provided at the opening to facilitate connection with an external gas or liquid passage.

[0075] In some embodiments of the present invention, the mounting base 4 forms an annular opening at one end facing the push sleeve 2, and a fourth step structure 404 is formed along the edge of the annular opening; a medium through groove 405 or a medium through hole is formed along the edge of the fourth step structure 404.

[0076] Second elastic member 7: defined as dead zone spring, installed in the cavity formed between mounting seat 4 and push sleeve 2 (the cavity is defined as dead zone spring cavity), second elastic member 7 is a pagoda type spring. The pagoda type spring is a key component for dead zone adjustment, the axial section of the pagoda type spring is conical, compared with the standard diameter cylindrical spring, the stiffness of the pagoda type spring is not constant, and the stiffness of the cylindrical spring is constant. After the cylindrical spring is compressed, the length changes, the stress value changes, but the stiffness does not change. After the pagoda type spring is compressed, the stress value changes, the length changes, and the stiffness changes.

[0077] In some embodiments of the application, the end of the second elastic member 7 with smaller radial width abuts the dead zone adjusting screw.

[0078] In order to improve the fixation of the second elastic member 7, a boss structure 203 is formed on the end face of the closed end of the push sleeve 2, the dead zone adjusting screw 6 and the side of the second elastic member 7 abutting each other form a clamping groove 601, the end of the second elastic member 7 on one side is located in the clamping groove 601, and the end on the other side is sleeved on the boss structure 203 (as a spring seat).

[0079] By adjusting the screwing depth of the dead zone adjusting screw 6, the compression amount of the second elastic member 7 is changed to change its stiffness. In addition to changing the spring diameter, the stiffness of the second elastic member 7 can also be changed in many ways such as changing the intercept and changing the wire diameter.

[0080] Dead zone adjusting screw 6: installed in the screw channel 402, abutting the second elastic member 7. When the dead zone adjusting screw 6 is screwed into the cavity formed between the mounting seat 4 and the push sleeve 2, the initial length of the second elastic member 7 is compressed, and conversely, when the dead zone adjusting screw 6 is screwed out of the cavity formed between the mounting seat 4 and the push sleeve 2, the initial length of the second elastic member 7 is elongated.

[0081] Third elastic member 8: installed in the cavity of the push sleeve 2, provided with a spring seat 9 on the opening end of the first end side of the housing 1, the third elastic member 8 is installed between the cavity bottom of the push sleeve 2 and the spring seat 9. When the spring seat 9 is subjected to an external force to move towards the closed end of the push sleeve 2, the third elastic member 8 is compressed.

[0082] Set value adjusting screw 10: installed in the screw hole of the housing handle 103, abutting the spring seat 9. The end of the set value adjusting screw 10 towards the spring seat 9 is pointed, and the side of the spring seat 9 towards the set value adjusting screw 10 has a groove, and the set value adjusting screw 10 is clamped in the groove to better push the spring seat 9.

[0083] In the above structure, the set value adjusting screw 10 acts on the third elastic member 8 through the spring seat to adjust the height of the third elastic member 8 to obtain different action values; the dead zone adjusting screw 6 is screwed into the screw channel 402, and the depth of the screwing into the screw channel 402 can be controlled to control the compression amount of the second elastic member 7 and adjust the length of the second elastic member 7 to achieve different stiffnesses.

[0084] In some embodiments of the application, a fine adjustment nut 11 is further included, which is installed at the open end of the push sleeve 2 and is threadedly connected with the push sleeve 2; the fine adjustment nut 11 has an axial through hole through which the set value adjusting screw 10 passes. The diameter of the axial through hole is larger than the outer diameter of the set value adjusting screw 10 so that there is no motion interference between them. A plurality of radial through holes are further arranged on the fine adjustment nut 11 to assist in adjusting the relative position between the fine adjustment nut 11 and the push sleeve 2.

[0085] The micro switch 12 is screwed on the side wall of the shell handle 103, and the contact thereof is connected with the pin of the connector 17 through the cable 20 passing through the shell cable groove 105.

[0086] An opening is formed between the second radial step structure 102 and the first radial step structure 101, and the contact button of the micro switch 12 is located at the opening and contacts the fine adjustment nut 11.

[0087] On the side where the micro switch 12 is installed, a protective cover 18 is arranged, the protective cover 18 is installed with the shell 1, and the shell first end and the micro switch 12 are located in the protective cover 18. To improve the sealing performance, the protective cover 18 is provided with a third sealing ring 19 at the joint with the shell 1. The radial through hole of the fine adjustment nut 11 is exposed by disassembling the protective cover 18, and the position of the fine adjustment nut 11 can be adjusted by using an adjusting tool.

[0088] The micro switch 12 can output different signals due to the different depths of the contact button thereof. The contact button of the micro switch 12 contacts the fine adjustment nut 11, and the initial position of the contact button of the micro switch can be set by adjusting the screwing depth of the fine adjustment nut 11 in the thread of the push ring of the air pressure sensing element.

[0089] The pressure switch is filled with pressure air, the pressure rises, reaches the upper switching value, at this time the micro switch 12 contact feedback outputs the off or on signal, at this time the corresponding compressed air pressure is the upper switching value of the pressure switch; during the air exhaust process of the pressure switch, the pressure decreases, the output switches to another state, at this time the micro switch 12 contact feedback outputs the on or off signal (opposite to the upper switching value state), at this time the corresponding compressed air pressure is the lower switching value of the pressure switch.

[0090] To improve the fixation between the push sleeve 2 and the housing 1, some embodiments of the present invention further include a locking sleeve 16, which is installed in the housing cavity and located between the push sleeve 2 and the housing 1, and the first elastic member 3 is located in the space formed by the locking sleeve and the push sleeve 2.

[0091] The working principle of the pressure switch provided by this invention is as follows.

[0092] The bellows has low stiffness, and the force generated by its deformation can be ignored; the change in the action force of the micro switch 12 during the button action and reset process is very small, so the difference in force value between the action point and the reset point can be ignored; the weight of each part is much smaller than the spring force, so the influence of the weight of each part can be ignored; the frictional resistance between relatively moving parts is small and can be ignored.

[0093] Define the second elastic element 7 as a dead zone spring. When external compressed air acts on the pneumatic sensing element through the mounting surface, air inlet groove, dead zone spring cavity, and air guide groove, it will generate a force that pushes the sleeve 2 to the right (e.g., Figure 1 The thrust (in the direction shown) (assuming the effective area of ​​air pressure action is S) gradually increases with the external compressed air pressure, and the resulting thrust pushes the push sleeve 2 to the right (as shown). Figure 1 Move the microswitch 12 (in the indicated direction) to drive the fine-tuning nut 11 to push the microswitch contact button until the microswitch 12 contact button moves to the actuation point. The corresponding compressed air pressure at this time is the upper switching value P of the pressure switch. u A force analysis of the entire push sleeve 2-fine-tuning nut 11 is performed as follows: Figure 5 As shown.

[0094] Among them, Fs u The force of the dead zone spring, Fq u The force P of compressed air u *S,Ft u Fw is the force required to set the spring's action, and Fw is the force required to activate the microswitch contact button.

[0095] Based on the above force analysis, the equilibrium equations are as follows.

[0096] Fs u +P u *S=Ft u +Fw (Formula 1)

[0097] When the external compressed air pressure decreases, under the action of the set spring force, sleeve 2 is pushed to the left (e.g., Figure 1 When the compressed air pressure decreases to a certain value (as shown in the direction), the microswitch 12 contact button moves to the reset point. The compressed air pressure at this time is the lower switching value P of the pressure switch. d A force analysis of the entire push sleeve 2-fine-tuning nut 11 is performed as follows: Figure 6as shown.

[0098] Fs d is the force of the dead zone spring, Fq d is the force of the compressed air, Ft d is the force of the set spring, and Fw is the force of the micro switch 12 contact button.

[0099] According to the above force analysis, the following equilibrium equation is listed.

[0100] Fs d +Fq d =Ft d +Fw (Formula 2)

[0101] Since the displacement of the push sleeve 2 before and after the above two state switching of the pressure switch is very small, it can be considered that the stiffness of the dead zone spring does not change in this displacement range, denoted as k s , and the stiffness of the set spring is denoted as k t . It is assumed that the displacement of the push sleeve 2 before and after the above micro switch 12 switches from action to reset is t (t is the differential travel of the micro switch 12), so in the above equilibrium equation, Fs d = Fs u +k s *t, Fq d =P d *S, Ft d =Ft u -k t *t, and the above equilibrium equation can be transformed as follows.

[0102] Fs u +k s *t+P d *S=Ft u -k t *t+F w (Formula 3)

[0103] The difference between the upper switching value P u and the lower switching value P d of the pressure switch is the dead zone ΔP of the pressure switch, and from Formulas 1-3, we have:

[0104]

[0105] Since the stiffness k s of the dead zone spring is variable, from Formula 4, by setting different stiffness k s of the dead zone spring, different dead zones of the pressure switch can be obtained, that is, when different dead zones are needed or dead zone adjustment is needed, the height of the dead zone spring (corresponding to different stiffness) can be adjusted by the dead zone adjusting screw 6 to achieve the purpose of dead zone adjustment.

[0106] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A pressure switch characterized by, The application relates to a dead zone adjusting device, which comprises the following parts: a shell: the shell is a two-end opening structure, a shell cavity is formed, a first radial step structure is formed along the opening of the first end of the shell cavity, a second radial step structure is arranged along the first radial step structure to the side away from the second end of the shell, the first radial step structure and the second radial step structure are both extended from the inner wall of the first end of the shell to the direction close to the radial center of the shell, a shell handle is formed at the second radial step structure and extended to the direction away from the second end of the shell; a pushing sleeve: one end is closed and the other end is opened, a pushing sleeve cavity is formed along the closed end to the open end, the closed end of the pushing sleeve is located at the side of the second end of the shell, a third radial step structure is formed along the outer wall of the closed end of the pushing sleeve and extended to the direction away from the radial center of the pushing sleeve, the open end of the pushing sleeve extends to the outside of the shell from the opening of the first radial step structure; a first elastic member: installed between the third radial step structure and the first radial step structure; a mounting seat: installed at the second opening end of the shell, a cavity is formed between the end of the mounting seat facing the closed end of the pushing sleeve and the closed end of the pushing sleeve, the mounting seat has a bolt channel penetrating through the cavity and the outer wall in the axial direction of the mounting seat, the mounting seat further has a medium passage penetrating through the outer wall and the cavity; a second elastic member: installed in the cavity formed between the mounting seat and the pushing sleeve, the second elastic member is a pagoda-shaped spring; a dead zone adjusting bolt: installed in the bolt channel and abutting against the second elastic member; a third elastic member: installed in the pushing sleeve cavity and provided with a spring seat on the side facing the first end of the shell; a set value adjusting bolt: installed in the bolt hole of the shell handle and abutting against the spring seat; further comprising a fine adjustment nut: installed at the open end of the pushing sleeve and threadedly connected with the pushing sleeve, the fine adjustment nut has an axial through hole, the set value adjusting bolt is threadedly connected with the through hole; further comprising a micro switch: installed on the side wall of the shell handle; an opening is formed between the second radial step structure and the first radial step structure, the contact button of the micro switch is located at the opening and in contact with the fine adjustment nut; further comprising a fixing ring: located in the gap between the pushing sleeve and the shell, one end of the first elastic member is connected with the third radial step structure and the other end is installed with the fixing ring.

2. The pressure switch of claim 1, wherein One end of the second elastic member with a smaller radial width abuts against the dead zone adjusting bolt.

3. The pressure switch of claim 2, wherein The side of the dead zone adjusting bolt abutting against the second elastic member forms a clamping groove, and the end of the second elastic member is located in the clamping groove.

4. The pressure switch of claim 1 wherein, The end of the mounting seat facing the pushing sleeve forms an annular opening, a fourth step structure is formed along the edge of the annular opening, and a medium passage groove or a medium passage hole is formed along the edge of the fourth step structure.

5. The pressure switch of claim 1 wherein, further comprising a locking sleeve: installed in the shell cavity and located between the pushing sleeve and the shell, the first elastic member is located in the space formed between the locking sleeve and the pushing sleeve.

6. The pressure switch of claim 1 or 5, wherein The first elastic member is an elastic bellows.

7. The pressure switch of claim 6 wherein, further comprising one or a combination of the following sealing structures: a first sealing ring is arranged between the outer wall of the mounting seat and the inner wall of the shell; a second sealing ring is arranged between the inner wall of the mounting seat and the outer wall of the pushing sleeve; a sealing gasket is arranged between the fixing ring and the first radial step structure.

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