Signal transmitter and filter assembly

Abstract

The invention belongs to the technical field of oil filtration, and particularly relates to a signal transmitter and filter assembly, a first mounting cavity and a second mounting cavity are arranged in a shell in a separated mode, and a first oil hole and a second oil hole are formed in the shell; the valve core is arranged in the mounting cavity I; the elastic piece is arranged in the first installation cavity, the end, away from the elastic piece, of the valve element is concavely arranged to form a containing cavity, a notch communicated with the containing cavity is formed in the side face of the end of the valve element, and oil passing through the first oil hole can enter the containing cavity and the end, provided with the containing cavity, of the valve element along the notch. The to-be-sensed part is arranged on the valve core and moves along with the valve core; the inductor is arranged in the second mounting cavity and used for detecting the distance of the to-be-induced part so as to obtain a trigger signal, and the second mounting cavity is arranged in a sealed mode and filled with liquid. The device can be well applied to a deepwater environment, is higher in detection sensitivity, is large in applicable pressure detection range, is higher in detection precision, and can meet the detection demands of more scenes.

Description

Technical Field

[0001] The invention belongs to the technical field of oil filtering, and in particular relates to a signal transmitter and a filter assembly. Background Art

[0002] Hydraulic systems are generally equipped with filters, and filter elements are installed in the filters to filter the oil in the hydraulic system. When the filter is working, the oil to be filtered enters from the oil inlet of the filter, is filtered by the filter element, and finally flows out from the oil outlet of the filter. The impurity particles in the oil are trapped in the filter screen of the filter element. In this way, more and more impurity particles are trapped, and the resistance of the oil passing through the filter will become greater and greater. Therefore, the filter element needs to be replaced in time. In response to this situation, a transmitter is usually set on the filter. The transmitter can detect the pressure difference between the inlet and outlet of the filter. When it is detected that the pressure difference between the inlet and outlet of the filter exceeds the set value, the transmitter will send an electrical signal and a corresponding visual indication to prompt the system operator to clean or replace the filter element in time to ensure the normal operation of the hydraulic system.

[0003] The air tightness level of commonly used signal transmitters is not high. They can be used normally in general air environments, but in underwater environments, especially deep water environments below one thousand meters, even if they are sealed, they are easily damaged by water pressure. Since the principle of the signal transmitter is basically to drive the valve core to move for triggering through the oil pressure difference at both ends of the valve core, some current signal transmitters have set up a more complex matching structure in the valve core area in order to improve the movement accuracy of the valve core. However, the complex structure of the valve core area will increase the resistance when the valve core moves, resulting in the valve core being able to move only within a fixed pressure range, resulting in a small applicable pressure detection range. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a signal transmitter and a filter assembly which has a simple structure, high sensitivity, a large detection range and is suitable for deep water environments.

[0005] The present invention provides a signal transmitter, comprising: A housing, wherein a first installation cavity and a second installation cavity are separated and arranged in the housing, an oil hole 1 for connecting the oil inlet of the filter with the first installation cavity, and an oil hole 2 for connecting the oil outlet of the filter with the first installation cavity are arranged on the housing, and the oil hole 2 is located on a side of the first installation cavity away from the second installation cavity; A valve core, which is arranged in the first installation cavity and can move toward the second oil hole or the second installation cavity under the action of an external force; An elastic member, the elastic member is arranged in the first installation cavity and is located between the side of the first installation cavity provided with the second oil hole and the valve core. The end of the valve core facing away from the elastic member is concavely arranged to form an accommodating cavity, and a notch communicating with the accommodating cavity is arranged on the side surface of the end of the valve core. The oil passing through the first oil hole can enter the accommodating cavity and the outside of the end of the valve core provided with the accommodating cavity along the notch; A portion to be sensed, the portion to be sensed is arranged on the valve core and moves with the valve core; The sensor is arranged in the second installation cavity, and the sensor is used to detect the distance of the part to be sensed to obtain a trigger signal. The second installation cavity is sealed and filled with liquid for resisting the external pressure of the shell.

[0006] Furthermore, the valve core is arranged concentrically with the installation cavity, and the side surface of the valve core contacts the inner side of the installation cavity, and the side surface of the valve core is axially spaced with a plurality of grooves, and the plurality of grooves are circumferentially arranged on the side surface of the valve core.

[0007] Furthermore, the valve core is provided with a groove on the outer side of one end of the accommodating cavity, and the groove is circumferentially arranged around the outer side of the valve core. An oil inlet cavity 1 is formed between the valve core and the inner side of the installation cavity 1 at the position of the groove, and an oil hole 1 is connected to the oil inlet cavity 1, and the notch is arranged on the groove.

[0008] Furthermore, one side of the installation cavity one close to the installation cavity two is recessed in the direction of the installation cavity two, and the inner side wall of the recessed area is an inclined surface or an arc surface, and the end face of one end of the valve core having the accommodating cavity is in linear contact with the inner side wall of the recessed area, and an oil inlet cavity two is formed between the end of the valve core having the accommodating cavity and the recessed area.

[0009] Furthermore, it also includes a fixing block, the part to be sensed is arranged in the accommodating cavity and encapsulated by the fixing block, and the accommodating cavity is filled with liquid for resisting external pressure in the encapsulation area of ​​the part to be sensed.

[0010] Furthermore, it also includes a hollow plug, and an opening is provided on the shell body on the side of the installation cavity one away from the installation cavity two, and the valve core and the elastic member can be moved into or out of the installation cavity one along the opening, and the hollow plug is threadedly connected in the opening, and the inner hole of the hollow plug forms the oil hole two, and the elastic member is arranged between the hollow plug and the valve core.

[0011] Furthermore, the position of the sensor in the second installation cavity can be adjusted and fixed along the moving direction of the valve core.

[0012] Furthermore, the shell includes an outer shell and a flange cover, the two ends of the inner shell are separated, the installation cavity 1 is arranged at one end of the outer shell, one end of the flange cover is passed through the other end of the outer shell and fixed, the installation cavity 2 is formed between the end of the flange cover and the inner part of the outer shell, and a circle of positioning grooves is circumferentially arranged on the outer side wall of the end of the flange cover, a sealing ring 1 and an elastic retaining ring are arranged in the positioning groove, the sensor is threadedly connected to the outer shell or the flange cover, and a watertight connector is also fixedly arranged on the flange cover, and the sensor is connected to the watertight connector.

[0013] Furthermore, the sensor is a magnetic proximity switch, and the part to be sensed is a magnetic member.

[0014] The present invention also provides a filter assembly, comprising a filter and an indicator as described above, wherein a connecting piece is provided on the filter, a mounting blind hole is provided on the connecting piece, an oil passage channel 1 and an oil passage channel 2 are provided on the side of the connecting piece, both the oil passage channel 1 and the oil passage channel 2 are connected with the mounting blind hole, and the oil passage channel 1 is connected in parallel with the oil inlet of the filter, and the oil passage channel 2 is connected in parallel with the oil outlet of the filter, the indicator is provided with an installation cavity 1 at one end thereof arranged in the mounting blind hole, the oil passage channel 1 is connected with the oil hole 1, and the oil passage channel 2 is connected with the oil hole 2, a sealing ring 2 and a sealing gasket are provided on the outer side of the shell of the indicator, the sealing ring 2 is located between the outer side of the shell and the inner side of the mounting blind hole, and between the oil passage channel 1 and the oil passage channel 2, and the sealing gasket is pressed onto the end face of the mounting blind hole.

[0015] The beneficial effect of the present invention is that by setting the sensor in a sealed installation cavity 2 filled with liquid, the sensor can be protected against the pressure outside the shell, and damage due to water pressure when operating in a deep water environment can be avoided. Therefore, the sensor is well suitable for use in a deep water environment. The arrangement of the accommodating cavity and the groove on the valve core can ensure that the oil can flow to the end of the valve core away from the elastic member when the oil enters along the oil hole, and ensure that the end of the valve core has a larger area in contact with the oil. The structural design is simple, and without increasing the number and complexity of the structural parts in the valve core area, it can help to make the area of ​​the end of the valve core affected by the oil pressure of the filter inlet equal to the area of ​​the end affected by the oil pressure of the filter outlet. When the area of ​​the end of the valve core affected by the oil pressure of the filter inlet is equal to the area of ​​the end affected by the oil pressure of the filter outlet, the value obtained by multiplying the pressure difference between the filter inlet and the oil outlet by the area is greater than the elastic force of the elastic member, which can drive the valve core to move. The valve core has a higher sensitivity to movement, a larger applicable pressure detection range, and a higher detection accuracy, which can meet the detection needs of more scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the signal transmitter of the present invention.

[0017] Figure 2 It is a schematic diagram of the longitudinal structure of the signal transmitter of the present invention.

[0018] Figure 3 It is a structural schematic diagram of the valve core of the present invention.

[0019] Figure 4 It is a schematic diagram of the assembly structure of the signal transmitter and the connecting piece of the present invention.

[0020] In the figure: 1-shell; 11-housing; 111-sealing ring 2; 112-sealing gasket; 12-flange cover; 121-sealing ring 1; 122-elastic retaining ring; 101-installation chamber 1; 102-installation chamber 2; 103-oil hole 1; 104-oil hole 2; 105-oil inlet chamber 1; 106-oil inlet chamber 2; 2-valve core; 21-accommodating chamber; 22-notch; 23-groove; 24-groove; 3-elastic part; 4-hollow plug; 5-portion to be sensed; 6-sensor; 7-fixing block; 8-watertight connector; 9-connecting piece; 91-installation blind hole; 92-oil passage 1; 93-oil passage 2. DETAILED DESCRIPTION

[0021] like Figure 1-Figure 3 As shown, the present invention provides a signal transmitter, which includes a housing 1, a valve core 2, an elastic member 3, a sensing portion 5 and a sensor 6. The housing 1 is provided with a mounting cavity 101 and a mounting cavity 2 102, which are separated. The mounting cavity 101 and the mounting cavity 2 102 are not intercommunication. The housing 1 is provided with an oil hole 103 for connecting the oil inlet of the filter with the mounting cavity 101, and an oil hole 2 104 for connecting the oil outlet of the filter with the mounting cavity 101. The oil hole 2 104 is located on the side of the mounting cavity 101 away from the mounting cavity 2 102. The valve core 2 is arranged in the mounting cavity 101, and can move toward the direction of the oil hole 2 104 or the mounting cavity 2 102 under the action of external force. The elastic member 3 is arranged in the installation cavity 101 and is located between the side of the installation cavity 101 provided with the oil hole 2 104 and the valve core 2. The end of the valve core 2 facing away from the elastic member 3 is concavely arranged. The concavely arranged area forms a receiving cavity 21 at the end of the valve core 2, and the side of the end of the valve core 2 is provided with a notch 22 connected to the receiving cavity 21. The oil entering the installation cavity 101 along the oil hole 103 enters the receiving cavity 21 and the end of the valve core 2 with the receiving cavity 21 through the notch 22. When the valve core 2 moves toward the direction of the oil hole 2 104, the elastic member 3 is compressed. The elastic member 3 is specifically a spring. The sensing part 5 is arranged on the valve core 2 and moves with the valve core 2. The sensor 6 is arranged in the installation cavity 2 102, and is used to detect the distance of the sensing part 5 to obtain a trigger signal. The installation cavity 2 102 is sealed and filled with a liquid, such as oil, for resisting the external pressure of the housing 1.

[0022] The transmitter provided by the present invention forms a non-mechanical contact detection structure because the installation cavity 101 and the installation cavity 2 102 are separated. By setting the sensor 6 in the installation cavity 2 102 which is sealed and filled with liquid, the sensor 6 can be protected to resist the pressure outside the shell 1, and can avoid damage due to water pressure when operating in a deep-water environment. Therefore, it is well suitable for use in a deep-water environment. When the transmitter is in use, the end of the valve core 2 facing the elastic member 3 will be affected by the elastic force of the elastic member 3 and the oil pressure of the filter oil outlet, while the end of the valve core 2 away from the elastic member 3 is only affected by the oil pressure of the filter oil inlet. The arrangement of the accommodating cavity 21 and the notch 22 on the valve core 2 can ensure that the oil can flow to the end of the valve core 2 away from the elastic member 3 when the oil enters along the oil hole 103, and ensure that the end of the valve core 2 can have a larger area in contact with the oil. The structural design is simple, without increasing the number and complexity of the structural parts in the valve core 2 area. Under this circumstance, it can help to make the area of ​​the valve core 2 at the end affected by the oil pressure of the filter inlet equal to the area of ​​the end affected by the oil pressure of the filter outlet. When the area of ​​the valve core 2 at the end affected by the oil pressure of the filter inlet is equal to the area of ​​the end affected by the oil pressure of the filter outlet, the value obtained by multiplying the pressure difference between the filter inlet and the oil outlet by the area is greater than the elastic force of the elastic member 3, that is, the valve core 2 can be driven to move. The valve core 2 has a higher sensitivity to movement, a larger applicable pressure detection range, and a higher detection accuracy, which can meet the detection needs of more scenarios.

[0023] The valve core 2 is concentrically arranged with the installation cavity 101, and the side of the valve core 2 contacts the inner side of the installation cavity 101, that is, when the valve core 2 moves, the side of the valve core 2 moves close to the inner side of the installation cavity 101. Preferably, the side of the valve core 2 is axially spaced with a plurality of grooves 24, and the plurality of grooves 24 are circumferentially arranged on the side of the valve core 2. When the transmitter is working, the oil flowing in the installation cavity 101 is oil, and the oil has a certain viscosity. When the gap between the side of the valve core 2 and the installation cavity 101 is small, it is difficult for the oil to directly pass from one side of the valve core 2 along the outer side of the valve core 2 and the inner side of the installation cavity 101. Therefore, in the present invention, no sealing member is arranged between the side of the valve core 2 and the inner side of the installation cavity 101, and only the cooperation between the side of the valve core 2 and the inner side of the installation cavity 101 is used to form a dynamic seal. The provision of the groove 24 can reduce the contact area between the side surface of the valve core 2 and the inner side of the installation cavity 101, thereby reducing the resistance of the valve core 2 when moving, and further improving the sensitivity of the valve core 2 when moving.

[0024] The valve core 2 is provided with a groove 23 on the outer side of one end of the accommodating cavity 21, and the groove 23 is circumferentially arranged around the outer side of the valve core 2. Inside the installation cavity 101, an oil inlet cavity 105 is formed at the position of the groove 23 between the valve core 2 and the inner side of the installation cavity 101, and the oil hole 103 is connected to the oil inlet cavity 105. The notch 22 is arranged on the groove 23, and the notch 22 is connected to the oil hole 103 through the oil inlet cavity 105, so as to ensure that the notch 22 can always be connected to the oil hole 103 during the movement of the valve core 2.

[0025] The side of the installation cavity 101 close to the installation cavity 2 102 is recessed in the direction of the installation cavity 2 102, and the inner side wall of the recessed area is an inclined surface or an arc surface. The end face of the valve core 2 provided with the accommodating cavity 21 is in line contact with the inner side wall of the recessed area, and the oil inlet cavity 2 106 is formed between the end of the valve core 2 provided with the accommodating cavity 21 and the recessed area. This setting can reduce the contact area between the end face of the valve core 2 and the inner side of the installation cavity 1 101, ensuring that the end face of the valve core 2 can have a larger area in contact with the oil, and further facilitating the equal oil pressure area at both ends of the valve core 2. Among them, the inner side wall of the recessed area is an inclined surface, the edge of the valve core 2 is inclined, and the inclination of the inclined area of ​​the valve core 2 is different from the inclination of the side wall in the recessed area, so as to form a line contact when in contact.

[0026] In one embodiment of the present invention, the sensing portion 5 is embedded in the valve core 2. In another embodiment of the present invention, it also includes a fixed block 7, and the accommodating cavity 21 is deepened. The sensing portion 5 and the fixed block 7 are both arranged in the accommodating cavity 21, and the sensing portion 5 is encapsulated in the accommodating cavity 21 through the fixed block 7. The oil entering the accommodating cavity 21 along the groove 22 is blocked by the fixed block 7 and acts on the outside of the fixed block 7. At the same time, the encapsulation area of ​​the sensing portion 5 in the accommodating cavity 21 is filled with liquid, such as oil, to resist external pressure. At the same time, combined with the liquid filled in the second installation cavity 102 and the filter oil, the transmitter can form a solid when in use, better resist the water pressure in the deep water environment, and ensure its working reliability. Reference Figure 2 As shown, the sum of the thicknesses of the fixed block 7 and the portion to be sensed 5 is less than the depth of the accommodating cavity 21. When the fixed block 7 encapsulates the portion to be sensed 5 in the accommodating cavity 21, the fixed block 7 as a whole is still inside the accommodating cavity 21 to ensure that when the oil acts on this end of the valve core 2, there is still an oil pressure action area that meets the design requirements.

[0027] The present invention also includes a hollow plug 4. An opening is provided on the housing 1 on the side of the installation cavity 101 away from the installation cavity 2 102. The valve core 2 and the elastic member 3 can be moved into or out of the installation cavity 101 along the opening. The hollow plug 4 is threadedly connected in the opening. The inner hole of the hollow plug 4 forms the oil hole 2 104. The elastic member 3 is arranged between the hollow plug 4 and the valve core 2. The above arrangement can facilitate the installation and overall assembly of the valve core 2 and the elastic member 3, and also facilitate the replacement of the elastic member 3 with different elastic forces. According to the depth of the screwing of the hollow plug 4, the preload force of the elastic member 3 can be adjusted, thereby adjusting the specific movement stroke of the valve core 2 under different oil pressures, thereby adjusting the pressure setting range of the transmitter.

[0028] The position of the sensor 6 in the installation cavity 102 can be adjusted along the moving direction of the valve core 2, and the position of the sensor 6 can be fixed after the adjustment. When the elastic force of the elastic member 3 is fixed and the position of the hollow plug 4 is fixed, the pressure setting range can also be adjusted by adjusting the position of the sensor 6, thereby making the pressure setting range larger and meeting the detection requirements of more scenarios and pressure ranges.

[0029] In the present invention, the shell 1 includes an outer shell 11 and a flange cover 12, the two ends of the inner shell 11 are separated and not interconnected, the installation cavity 101 is arranged at one end of the outer shell 11, one end of the flange cover 12 is penetrated into the other end of the outer shell 11 and fixed by screws and gaskets, the installation cavity 2 102 is formed between the end of the flange cover 12 and the inner part of the end of the outer shell 11, and a circle of positioning grooves is circumferentially provided on the outer side wall of the end of the flange cover 12, a sealing ring 121 and an elastic retaining ring 122 are arranged in the positioning groove, the sensor 6 is threadedly connected to the outer shell 11 or the flange cover 12, and a watertight connector 8 is also fixedly arranged on the flange cover 12, the sensor 6 is connected to the watertight connector 8, while facilitating the connection between the sensor 6 and the external controller to transmit signals, because the watertight connector 8 itself has good underwater sealing performance, the possibility of the transmitter being damaged by water pressure or water flow is reduced. In this arrangement, the sensor 6 is threadedly assembled, the connection is stable and the adjustment is convenient, and the sealing ring 121 and the elastic retaining ring 122 are used to seal the housing 11 and the flange cover 12, which can withstand greater pressure and extend the life of the sealing ring 121.

[0030] In the present invention, the sensor 6 is specifically a magnetic proximity switch, and the part to be sensed 5 is specifically a magnetic part, such as a magnet. By moving the valve core 2, the distance between the magnet assembled in the valve core 2 and the magnetic proximity switch sensor is changed, thereby obtaining an electrical signal related to the blockage of the filter element.

[0031] The present invention also provides a filter assembly, including a filter (not shown) and an indicator as described above, wherein the filter is provided with a connector 9, which is specifically provided on the filter housing and is a part of the filter housing dedicated to installing the indicator. The connector 9 is provided with a mounting blind hole 91, and an oil passage 1 92 and an oil passage 2 93 are provided on the side of the connector 9, and the oil passage 1 92 and the oil passage 2 93 are both connected to the mounting blind hole 91, and the oil passage 1 92 is connected in parallel with the oil inlet of the filter, and the oil passage 2 93 is connected in parallel with the oil outlet of the filter. The indicator is provided with an installation cavity 101 at one end thereof, which is arranged in the mounting blind hole 91, and the oil passage 1 92 is connected to the oil hole 1 103. The oil passage 93 is connected to the oil hole 104. The outer side of the housing 1 of the transmitter is provided with a sealing ring 111 and a sealing gasket 112. The sealing ring 111 is located between the outer side of the housing 1 and the inner side of the mounting blind hole 91, and between the oil passage 92 and the oil passage 93, isolating the oil at the oil inlet and the oil outlet of the filter. The sealing gasket 112 is pressed on the end face of the mounting blind hole 91 to prevent the oil from leaking from the assembly of the transmitter and the connector 9. The filter assembly is better suited for underwater, especially deep water environments, due to the provision of the above-mentioned transmitter, and has higher trigger sensitivity and higher detection accuracy.

[0032] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0033] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A signal transmitter, characterized in that: include: A housing (1), wherein a first installation cavity (101) and a second installation cavity (102) are separately arranged in the housing (1), an oil hole (103) for connecting an oil inlet of a filter with the first installation cavity (101), and an oil hole (104) for connecting an oil outlet of the filter with the first installation cavity (101), the housing (1) being located on a side of the first installation cavity (101) away from the second installation cavity (102); A valve core (2), the valve core (2) being arranged in the first installation cavity (101) and being movable towards the second oil hole (104) or the direction of the second installation cavity (102) under the action of an external force; An elastic member (3), the elastic member (3) being arranged in the first installation cavity (101) and being located between a side of the first installation cavity (101) provided with the second oil hole (104) and the valve core (2); an end of the valve core (2) which is away from the elastic member (3) is arranged inwardly concavely to form a receiving cavity (21); and a notch (22) which communicates with the receiving cavity (21) is arranged on the side surface of the end of the valve core (2); oil passing through the first oil hole (103) can enter the receiving cavity (21) and the outside of the end of the valve core (2) provided with the receiving cavity (21) along the notch (22); A portion to be sensed (5), the portion to be sensed (5) being arranged on the valve core (2) and moving along with the valve core (2); A sensor (6), wherein the sensor (6) is arranged in the second installation cavity (102), and the sensor (6) is used to detect the distance of the part to be sensed (5) to obtain a trigger signal, and the second installation cavity (102) is sealed and filled with a liquid for resisting the external pressure of the housing (1).

2. The signal transmitter as claimed in claim 1, characterized in that: The valve core (2) is arranged concentrically with the installation cavity (101), and the side surface of the valve core (2) contacts the inner side of the installation cavity (101). The side surface of the valve core (2) is provided with a plurality of grooves (24) at axial intervals, and the plurality of grooves (24) are all arranged circumferentially on the side surface of the valve core (2).

3. The signal transmitter as claimed in claim 2, characterized in that: The valve core (2) is provided with a groove (23) on the outer side of one end of the accommodating cavity (21), the groove (23) being arranged circumferentially around the outer side of the valve core (2), an oil inlet cavity (105) is formed between the valve core (2) and the inner side of the mounting cavity (101) at the position of the groove (23), the oil hole (103) is in communication with the oil inlet cavity (105), and the notch (22) is arranged on the groove (23).

4. The signal transmitter as claimed in claim 3, characterized in that: The side of the installation cavity one (101) close to the installation cavity two (102) is recessed in the direction of the installation cavity two (102), and the inner side wall of the recessed area is an inclined surface or an arc surface. The end face of one end of the valve core (2) provided with the accommodating cavity (21) is in linear contact with the inner side wall of the recessed area, and the oil inlet cavity two (106) is formed between the end of the valve core (2) provided with the accommodating cavity (21) and the recessed area.

5. The signal transmitter according to any one of claims 1 to 4, characterized in that: It also comprises a fixing block (7), the portion to be sensed (5) is arranged in the accommodating cavity (21) and is encapsulated by the fixing block (7), and a liquid for resisting external pressure is filled in the encapsulation area of ​​the portion to be sensed (5) in the accommodating cavity (21).

6. The signal transmitter according to any one of claims 1 to 4, characterized in that: It also includes a hollow plug (4), an opening is provided on the housing (1) at a side of the first installation cavity (101) facing away from the second installation cavity (102), the valve core (2) and the elastic member (3) can both move into or out of the first installation cavity (101) along the opening, the hollow plug (4) is threadedly connected in the opening, the inner hole of the hollow plug (4) forms the second oil hole (104), and the elastic member (3) is arranged between the hollow plug (4) and the valve core (2).

7. The signal transmitter as claimed in claim 6, characterized in that: The position of the sensor (6) in the second installation cavity (102) can be adjusted and fixed along the moving direction of the valve core (2).

8. The signal transmitter as claimed in claim 7, characterized in that: The housing (1) comprises an outer shell (11) and a flange cover (12), the inner ends of the outer shell (11) are separated, the first installation cavity (101) is arranged at one end of the outer shell (11), one end of the flange cover (12) is inserted into the other end of the outer shell (11) and fixed, the second installation cavity (102) is formed between the end of the flange cover (12) and the inner end of the outer shell (11), and a circle of positioning grooves is circumferentially provided on the outer side wall of the end of the flange cover (12), a sealing ring (121) and an elastic retaining ring (122) are arranged in the positioning groove, the sensor (6) is threadedly connected to the outer shell (11) or the flange cover (12), a watertight connector (8) is also fixedly arranged on the flange cover (12), and the sensor (6) is connected to the watertight connector (8).

9. The signal transmitter according to any one of claims 1 to 4, 7 and 8, characterized in that: The sensor (6) is a magnetic proximity switch, and the portion to be sensed (5) is a magnetic member.

10. A filter assembly, characterized in that: The invention comprises a filter and an indicator as claimed in any one of claims 1 to 9, wherein the filter is provided with a connecting piece (9), the connecting piece (9) is provided with a mounting blind hole (91), a side of the connecting piece (9) is provided with an oil passage channel 1 (92) and an oil passage channel 2 (93), the oil passage channel 1 (92) and the oil passage channel 2 (93) are both connected to the mounting blind hole (91), and the oil passage channel 1 (92) is connected in parallel with the oil inlet of the filter, and the oil passage channel 2 (93) is connected in parallel with the oil outlet of the filter, and the indicator is provided with a mounting cavity 1 (10 One end of the transmitter (1) is arranged in the mounting blind hole (91), the oil passage channel (92) is connected to the oil hole (103), the oil passage channel (93) is connected to the oil hole (104), and the outer side of the housing (1) of the transmitter is provided with a sealing ring (111) and a sealing gasket (112), the sealing ring (111) is located between the outer side of the housing (1) and the inner side of the mounting blind hole (91), and between the oil passage channel (92) and the oil passage channel (93), and the sealing gasket (112) is press-fitted on the end surface of the mounting blind hole (91).

Images