CN217502737U

CN217502737U - Pressure reducing valve

Info

Publication number: CN217502737U
Application number: CN202221405693.9U
Authority: CN
Inventors: 许辉
Original assignee: Shanghai Likeng Technology Co ltd
Current assignee: Shanghai Likeng Technology Co ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2022-09-27
Anticipated expiration: 2032-06-07

Abstract

A pressure reducing valve comprises a valve block, wherein a valve cavity, an oil inlet channel and an oil outlet channel which are communicated with the valve cavity are arranged in the valve block, a supporting seat, a valve seat and a restrictor are arranged in the valve cavity, the valve seat is accommodated in the supporting seat and positioned at the lower end of the supporting seat, the supporting seat is provided with an oil inlet which is communicated with the oil inlet channel and the inside of the supporting seat in a penetrating manner, the valve seat is provided with an oil outlet which is communicated with the inside of the supporting seat in a penetrating manner, the restrictor is arranged below the valve seat, and the restrictor is provided with a throttling hole in a penetrating manner along the axial direction; the pressure reducing valve also comprises a movable iron arranged above the valve seat, and the movable iron can move up and down to open the oil outlet or seal the oil outlet; when the moving iron moves downwards, the oil outlet is sealed, so that the oil inlet channel is not communicated with the oil outlet channel; and when the moving iron moves upwards, the oil outlet is opened, so that the oil inlet channel is communicated with the oil outlet channel sequentially through the oil inlet, the oil outlet and the throttling hole.

Description

Pressure reducing valve

Technical Field

The utility model relates to the technical field of valves, especially, relate to a relief pressure valve.

Background

The hydraulic brake system of the passenger car is changing to the wire control direction comprehensively, and an electronic mechanical hydraulic system is the mainstream type. Currently, a brake-by-wire system mainly comprises a master cylinder, an electric cylinder, a wheel cylinder, an electromagnetic valve, a sensor and an ECU; after a driver steps on a brake pedal, an ECU of the brake-by-wire system detects a change value of a pedal displacement sensor connected with the pedal, and then determines how much brake pressure needs to be provided by an electric cylinder and requires a motor to work according to the change value, so that brake fluid is compressed, hydraulic pressure is built and is transmitted to the wheel cylinder, and the requirement of providing brake force for a vehicle is met.

Pressure reducing valves are widely used in hydraulic control systems, and are required in hydraulic brake systems of vehicles, mainly for reducing inlet pressure to a certain required outlet pressure. However, the overall structure of the conventional pressure reducing valve is still relatively complex, and the orifice is generally arranged in the support seat, so that the process difficulty of parts is relatively high, the cost is relatively high, and the application of the pressure reducing valve in the industrial field is limited, so that the conventional pressure reducing valve needs to be improved.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model aims at providing a pressure reducing valve that overall structure is fairly simple, the technology degree of difficulty and the cost of part are lower.

The utility model provides a pressure reducing valve, including the valve piece, be equipped with the valve pocket in the valve piece and with the oil feed passageway and the passageway that produces oil that the valve pocket communicates, be provided with supporting seat, disk seat and flow controller in the valve pocket, the disk seat is acceptd in the supporting seat and is located the lower extreme of supporting seat, the supporting seat runs through and is equipped with the oil inlet that communicates oil feed passageway and supporting seat inside, the disk seat runs through and is equipped with the oil-out that communicates oil feed passageway and supporting seat inside, the flow controller sets up in the below of disk seat, the flow controller runs through along the axial and is equipped with the orifice; the pressure reducing valve also comprises a moving iron arranged above the valve seat, and the moving iron can move up and down to open the oil outlet or seal the oil outlet; when the moving iron moves downwards, the oil outlet is sealed, so that the oil inlet channel is not communicated with the oil outlet channel; and when the moving iron moves upwards, the oil outlet is opened, so that the oil inlet channel is communicated with the oil outlet channel sequentially through the oil inlet, the oil outlet and the throttling hole.

In one embodiment, the supporting seat is a hollow ring shape and is in a funnel shape with a wide top and a narrow bottom, the oil inlet is arranged by penetrating through the side wall of the supporting seat, a first cavity is formed inside the supporting seat, and the lower end of the movable iron extends into the first cavity.

In an embodiment, the inner diameter of the upper end of the supporting seat is larger than the inner diameter of the lower end of the supporting seat, a step portion is formed between the upper end of the supporting seat and the lower end of the supporting seat, the oil inlet penetrates through the side wall of the upper end of the supporting seat and is arranged, and the oil inlet is located above the step portion.

In one embodiment, a sealing ring is arranged outside the supporting seat in the valve cavity, and the sealing ring is located below the step part and clamped between the inner wall of the valve cavity and the outer wall of the supporting seat.

In one embodiment, the valve seat is in an inverted cylindrical shape, the oil outlet penetrates through the center of the top plate of the valve seat, a second cavity is formed inside the valve seat, and the throttling device extends into the second cavity.

In one embodiment, the restrictor comprises an insertion part and a head part, wherein the diameter of the head part is larger than that of the insertion part, the insertion part is inserted into the second cavity from the bottom end of the valve seat and is fixedly connected with the valve seat, the head part is positioned outside the valve seat, the insertion part is provided with a communication hole in a penetrating mode along the axial direction, the throttling hole is arranged in the head part in a penetrating mode along the axial direction, and the aperture of the communication hole is larger than that of the throttling hole; when the moving iron moves upwards to open the oil outlet, the oil inlet channel is communicated with the oil outlet channel sequentially through the oil inlet, the first cavity, the oil outlet, the second cavity, the communicating hole and the throttling hole.

In one embodiment, the oil outlet port, the communication hole and the orifice are aligned up and down, and the oil outlet passage is located right below the orifice.

In one embodiment, the bottom of the support seat is provided with a flange surface protruding inwards, the bottom of the valve seat is supported on the flange surface, and the flange surface is located between the bottom and the head of the valve seat.

In one embodiment, the outer wall of the valve seat and the inner wall of the lower end of the support seat are in interference fit, and the outer wall of the insert portion and the inner wall of the valve seat are in interference fit.

In one embodiment, the restrictor is an injection molded part made of plastic.

In one embodiment, the pressure reducing valve is an electromagnetic valve, the pressure reducing valve further comprises a coil and a fixed iron, the fixed iron is arranged above the movable iron and is fixed, an elastic part is arranged between the fixed iron and the movable iron, the movable iron is driven to move upwards and compress the elastic part when the coil is powered on, and the elastic part pushes the movable iron to move downwards through elastic force when the coil is powered off.

In one embodiment, the pressure reducing valve further comprises a magnetism isolating pipe, the inside of the magnetism isolating pipe is a cavity, the fixed iron and the moving iron are contained in the magnetism isolating pipe, and the upper end of the supporting seat is fixedly connected with the lower end of the magnetism isolating pipe.

In one embodiment, the outer wall of the lower end of the magnetism isolating pipe and the inner wall of the upper end of the supporting seat are fixed through laser welding.

In one embodiment, the lower end of the moving iron is in a cone shape with the diameter decreasing from top to bottom, and a steel ball for sealing the oil outlet is fixedly connected to the bottom of the moving iron.

The embodiment of the utility model provides a pressure reducing valve is equipped with the valve pocket in the valve piece and with the oil feed passageway and the passageway of producing oil of valve pocket intercommunication, be provided with supporting seat, disk seat and flow controller in the valve pocket, the supporting seat runs through and is equipped with the inside oil inlet of intercommunication oil feed passageway and supporting seat, the disk seat runs through and is equipped with the intercommunication and goes out the oil-out of oil passageway and supporting seat inside, the flow controller sets up in the below of disk seat, the flow controller runs through along the axial and is equipped with the orifice. The pressure reducing valve can enable the oil inlet channel to be communicated with the oil outlet channel or to be blocked and not communicated through the up-and-down movement of the movable iron. The whole structure of the pressure reducing valve is simple, the pressure reducing valve is different from the conventional design of the throttling hole in the supporting seat, the supporting seat does not contain the throttling hole, the process difficulty is low, and the cost is low.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of the pressure reducing valve in the power-on state according to the embodiment of the present invention.

Fig. 2 is a partial structural schematic view of the pressure reducing valve in fig. 1.

Fig. 3 is a schematic structural diagram of the pressure reducing valve in the power-off state according to the embodiment of the present invention.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the description of the present invention, all other embodiments obtained by a person skilled in the art without making creative efforts belong to the protection scope of the present invention.

The terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", and the like, refer to an orientation or positional relationship based on that shown in the drawings, or that is conventionally placed during use of the invention, for convenience of description and simplicity of illustration, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the invention.

Moreover, the terms "first," "second," "third," and the like are used solely to distinguish between similar elements and not to indicate or imply relative importance or a particular order.

Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

An embodiment of the present invention provides a pressure reducing valve for reducing pressure, reducing inlet pressure to a certain required outlet pressure, and specifically, the pressure reducing valve can be applied to a hydraulic braking system of a passenger car, for example, an anti-lock brake system (ABS), an electronic stability control system (ESC) or a brake-by-wire system, but not limited thereto, and the pressure reducing valve can be applied to other hydraulic control systems besides the above.

Referring to fig. 1 and 2, the pressure reducing valve includes a valve block 10, and a valve cavity 11, and an oil inlet passage 13 and an oil outlet passage 14 communicated with the valve cavity 11 are disposed in the valve block 10. The valve cavity 11 is internally provided with a supporting seat 17, a valve seat 18 and a restrictor 41. The valve seat 18 is accommodated in the support seat 17 and is located at the lower end of the support seat 17. The supporting seat 17 is provided with an oil inlet 22 through which the oil inlet channel 13 is communicated with the inside of the supporting seat 17. The valve seat 18 is provided with an oil outlet 23 which communicates the oil outlet passage 14 with the inside of the support seat 17. The orifice 41 is provided below the valve seat 18, and an orifice 42 is provided to axially penetrate the orifice 41.

Specifically, the pressure reducing valve is an electromagnetic valve, and the pressure reducing valve further comprises a moving iron 19 arranged above the valve seat 18, wherein the moving iron 19 can move up and down to open the oil outlet 23 or seal the oil outlet 23. Fig. 1 shows the power-on state of the pressure reducing valve, please refer to fig. 1, in the power-on state, the moving iron 19 is driven to move upwards, and the oil outlet 23 is opened when the moving iron 19 moves upwards, so that the oil inlet channel 13 is communicated with the oil outlet channel 14 sequentially through the oil inlet 22, the oil outlet 23 and the throttle hole 42.

Fig. 3 shows a power-off state of the pressure reducing valve, please refer to fig. 3, in the power-off state, the moving iron 19 is driven to move downwards, and when the moving iron 19 moves downwards, the oil outlet 23 is sealed, so that the oil inlet channel 13 is not communicated with the oil outlet channel 14.

The supporting seat 17 is a hollow ring shape and is in a funnel shape with a wide upper part and a narrow lower part. The oil inlet 22 is arranged through the side wall of the support seat 17. The inside of the supporting seat 17 forms a first cavity 51, and the lower end of the moving iron 19 extends into the first cavity 51, so that the oil outlet 23 can be sealed by the moving iron 19. Specifically, the inner diameter of the upper end of the support seat 17 is larger than the inner diameter of the lower end of the support seat 17, and a stepped portion 25 is formed between the upper end of the support seat 17 and the lower end of the support seat 17. The oil inlet 22 is arranged through the side wall of the upper end of the supporting seat 17, and the oil inlet 22 is positioned above the step portion 25. A sealing ring 28 is arranged outside the supporting seat 17 in the valve cavity 11, and the sealing ring 28 is positioned below the step part 25 and is clamped between the inner wall of the valve cavity 11 and the outer wall of the supporting seat 17. By providing the sealing ring 28, the oil in the oil inlet passage 13 and the oil outlet passage 14 cannot leak through the outside of the support seat 17, and can only communicate through the oil inlet 22, the first cavity 51 inside the support seat 17, the oil outlet 23, and the orifice 42.

Specifically, the valve seat 18 is in the shape of an inverted cylinder, the valve seat 18 includes a ring-shaped side wall and a top plate located at the top end of the side wall, and the oil outlet 23 is arranged at the center of the top plate of the valve seat 18 in a penetrating manner. The interior of the valve seat 18 forms a second cavity 52 and the restrictor 41 extends into the second cavity 52. The valve seat 18 is fixedly connected with the lower end of the supporting seat 17, specifically, the valve seat 18 and the lower end of the supporting seat 17 are pressed in an interference fit manner, that is, the outer wall of the valve seat 18 and the inner wall of the lower end of the supporting seat 17 are in an interference fit manner.

The restrictor 41 comprises an insertion part 43 and a head part 44, the diameter of the head part 44 is larger than that of the insertion part 43, the insertion part 43 is inserted into the second cavity 52 from the bottom end of the valve seat 18 and is fixedly connected with the valve seat 18, the head part 44 is positioned outside the valve seat 18, the insertion part 43 is provided with a communication hole 45 in an axial direction in a penetrating mode, the orifice 42 is provided in the head part 44 in an axial direction in a penetrating mode, and the diameter of the communication hole 45 is larger than that of the orifice 42. When the oil outlet 23 is opened by moving the moving iron 19 upwards, the oil inlet channel 13 is communicated with the oil outlet channel 14 sequentially through the oil inlet 22, the first cavity 51, the oil outlet 23, the second cavity 52, the communication hole 45 and the throttling hole 42. Specifically, the oil outlet 23, the communication hole 45, and the orifice 42 are aligned up and down. The oil inlet passage 13 is provided in the horizontal direction, the oil outlet passage 14 is provided in the vertical direction, and the oil outlet passage 14 is located directly below the throttle hole 42.

Specifically, the restrictor 41 and the valve seat 18 are press-fitted with interference, that is, an interference fit is made between an outer wall of the insertion portion 43 of the restrictor 41 and an inner wall of the valve seat 18.

In the present embodiment, the orifice 42 has a hole diameter of 0.3mm to 0.6mm and a length of 0.3mm to 0.4 mm. If the diameter of the orifice 42 is too large, the throttling effect may be impaired, and if the length of the orifice 42 is too large, the flow rate may be too small.

The bottom of the support seat 17 is provided with a flange surface 31 protruding inward, the bottom of the valve seat 18 is supported on the flange surface 31, and the flange surface 31 is located between the bottom of the valve seat 18 and the head 44 of the restrictor 41 to prevent the valve seat 18 from being displaced relative to the support seat 17 by receiving hydraulic pressure for a long time.

Further, an annular filter screen 32 is arranged in the valve cavity 11, and the annular filter screen 32 is arranged between the oil inlet passage 13 and the oil inlet 22. The filter screen is arranged at the position of the oil inlet 22 in the valve cavity 11, so that impurities in the oil can be filtered, and the impurities are prevented from entering the valve cavity 11.

Specifically, the pressure reducing valve is an electromagnetic valve, the pressure reducing valve further comprises a coil 37 and a fixed iron 38, the fixed iron 38 is arranged above the movable iron 19, the fixed iron 38 is fixed, an elastic part 24 is arranged between the fixed iron 38 and the movable iron 19, one end of the elastic part 24 abuts against the fixed iron 38, and the other end of the elastic part 24 abuts against the movable iron 19. Specifically, the elastic member 24 may be a spring, but is not limited thereto. In the present embodiment, the movable iron 19 has a recess (not numbered) formed at an end facing the fixed iron 38, and the spring is accommodated in the recess. When the coil 37 is electrified, the moving iron 19 is driven to move upwards and compress the elastic piece 24, and when the coil 37 is powered off, the elastic piece 24 pushes the moving iron 19 to move downwards through elastic force.

Further, the pressure reducing valve further includes a magnetic isolation pipe 39, an upper end of the magnetic isolation pipe 39 is sealable, a lower end thereof is open, an interior of the magnetic isolation pipe 39 is a cavity, and the fixed iron 38 and the moving iron 19 are accommodated in the magnetic isolation pipe 39 through the opening at the lower end of the magnetic isolation pipe 39. The fixed iron 38 is fixed in the magnetism isolating pipe 39, and the moving iron 19 is movable up and down in the magnetism isolating pipe 39. The coil 37 is disposed outside the magnetism isolating pipe 39. The fixed iron 38 is fixedly connected with the upper end of the magnetism isolating pipe 39, and specifically, the outer wall of the fixed iron 38 and the inner wall of the upper end of the magnetism isolating pipe 39 are fixed through laser welding. The upper end of the supporting seat 17 is fixedly connected with the lower end of the magnetism isolating pipe 39, and specifically, the outer wall of the lower end of the magnetism isolating pipe 39 and the inner wall of the upper end of the supporting seat 17 are fixed through laser welding.

Furthermore, the lower end of the moving iron 19 is in a cone shape with the diameter decreasing from top to bottom, a steel ball 46 for sealing the oil outlet 23 is fixedly connected to the bottom of the moving iron 19, the oil outlet 23 is sealed through the steel ball 46, and the effect is better.

When the coil 37 is electrified, the fixed iron 38 and the moving iron 19 are magnetized to generate suction force, because the fixed iron 38 and the magnetism isolating pipe 39 are fixed by welding and cannot move, the moving iron 19 moves upwards towards the fixed iron 38 due to the attraction of electromagnetic force and overcomes the spring force to compress the spring, finally the moving iron 19 drives the steel ball 46 to move upwards to separate from the valve seat 18, the oil outlet 23 is opened, as shown in fig. 1, at the moment, the oil inlet channel 13 is communicated with the oil outlet channel 14 sequentially through the oil inlet 22, the first cavity 51, the oil outlet 23, the second cavity 52, the communication hole 45 and the throttle hole 42, and brake fluid flows downwards to realize the pressure reduction function.

When the coil 37 is powered off, the spring pushes the moving iron 19 downwards by using elastic force, and finally the moving iron 19 drives the steel ball 46 to move downwards to be attached to the top plate of the valve seat 18 and seal the oil outlet 23, as shown in fig. 3, at this time, the oil inlet channel 13 and the oil outlet channel 14 are blocked and not communicated.

In this embodiment, the valve block 10 may be made of aluminum, the moving iron 19 and the fixed iron 38 may be made of mild steel, and the support seat 17, the valve seat 18 and the magnetism isolating pipe 39 may be made of free-cutting stainless steel. The restrictor 41 may be an injection molded part made of plastic, which has low process difficulty and low cost.

The embodiment of the utility model provides a pressure reducing valve is equipped with valve pocket 11 in the valve piece 10 and with the oil feed passageway 13 and the passageway 14 that produces oil of 11 intercommunications of valve pocket, be provided with supporting seat 17, disk seat 18 and throttle 41 in the valve pocket 11, supporting seat 17 runs through and is equipped with intercommunication oil feed passageway 13 and the inside oil inlet 22 of supporting seat 17, disk seat 18 runs through and is equipped with the intercommunication and produces oil passageway 14 and the inside oil-out 23 of supporting seat 17, throttle 41 sets up in disk seat 18's below, throttle 41 runs through along the axial and is equipped with orifice 42. The pressure reducing valve can make the oil inlet channel 13 communicated with the oil outlet channel 14 or be blocked and not communicated through the up-and-down movement of the movable iron 19. The whole structure of the pressure reducing valve is simple, the pressure reducing valve is different from the conventional design of the throttling hole in the supporting seat, the supporting seat does not contain the throttling hole, the process difficulty is low, and the cost is low.

In the present embodiment, the pressure reducing valve is an electromagnetic valve, and the restrictor 41 may not be installed first when the stroke is set, so that the stroke setting of the electromagnetic valve is not hindered.

The above embodiments are only specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A pressure reducing valve comprises a valve block, wherein a valve cavity, an oil inlet channel and an oil outlet channel are arranged in the valve block, the oil inlet channel and the oil outlet channel are communicated with the valve cavity, and the pressure reducing valve is characterized in that a supporting seat, a valve seat and a throttler are arranged in the valve cavity; the pressure reducing valve also comprises a movable iron arranged above the valve seat, and the movable iron can move up and down to open the oil outlet or seal the oil outlet; when the moving iron moves downwards, the oil outlet is sealed, so that the oil inlet channel is not communicated with the oil outlet channel; and when the moving iron moves upwards, the oil outlet is opened, so that the oil inlet channel is communicated with the oil outlet channel sequentially through the oil inlet, the oil outlet and the throttling hole.

2. The pressure reducing valve according to claim 1, wherein the support seat is a hollow ring shape and has a funnel shape with a wide top and a narrow bottom, the oil inlet is disposed through a side wall of the support seat, a first cavity is formed inside the support seat, and a lower end of the movable iron extends into the first cavity.

3. The pressure reducing valve according to claim 2, wherein an inner diameter of an upper end of the support seat is larger than an inner diameter of a lower end of the support seat, a step portion is formed between the upper end of the support seat and the lower end of the support seat, the oil inlet is provided through a side wall of the upper end of the support seat, and the oil inlet is located above the step portion.

4. The pressure reducing valve according to claim 3, wherein a sealing ring is disposed in the valve chamber outside the support seat, and the sealing ring is located below the step portion and sandwiched between an inner wall of the valve chamber and an outer wall of the support seat.

5. The pressure reducing valve according to claim 2, wherein the valve seat is formed in an inverted cylindrical shape, the oil outlet port is disposed through a center portion of a top plate of the valve seat, a second cavity is formed inside the valve seat, and the restrictor extends into the second cavity.

6. The pressure reducing valve according to claim 5, wherein the restrictor comprises an insertion portion and a head portion, the diameter of the head portion is larger than that of the insertion portion, the insertion portion is inserted into the second cavity from the bottom end of the valve seat and is fixedly connected with the valve seat, the head portion is located outside the valve seat, a communication hole is axially and penetratingly formed in the insertion portion, the orifice is axially and penetratingly formed in the head portion, and the diameter of the communication hole is larger than that of the orifice; when the moving iron moves upwards to open the oil outlet, the oil inlet channel is communicated with the oil outlet channel sequentially through the oil inlet, the first cavity, the oil outlet, the second cavity, the communication hole and the throttling hole.

7. The pressure reducing valve according to claim 6, wherein said oil outlet port, said communication hole and said orifice are aligned up and down, and said oil outlet passage is located directly below said orifice.

8. The pressure relief valve as claimed in claim 6 wherein the bottom of the seat is inwardly convexly provided with a flange face against which the bottom of the seat rests, the flange face being located between the bottom of the seat and the head.

9. The pressure relief valve of claim 6, wherein the outer wall of the valve seat and the inner wall of the lower end of the support seat are in an interference fit, and the outer wall of the insert and the inner wall of the valve seat are in an interference fit.

10. The pressure relief valve of claim 6, wherein the restrictor is an injection molded piece made of plastic.

11. The pressure reducing valve according to any one of claims 1 to 10, wherein the pressure reducing valve is a solenoid valve, the pressure reducing valve further comprises a coil and a fixed iron, the fixed iron is disposed above the movable iron, the fixed iron is fixed, an elastic member is disposed between the fixed iron and the movable iron, the coil drives the movable iron to move upward and compress the elastic member when the coil is powered on, and the elastic member pushes the movable iron to move downward by an elastic force when the coil is powered off.

12. The pressure reducing valve according to claim 11, further comprising a magnetism isolating pipe, wherein the magnetism isolating pipe has a hollow interior, the fixed iron and the movable iron are accommodated in the magnetism isolating pipe, and an upper end of the support base is fixedly connected to a lower end of the magnetism isolating pipe.

13. The pressure reducing valve according to claim 12, wherein the outer wall of the lower end of the magnetism isolating pipe and the inner wall of the upper end of the support seat are fixed by laser welding.

14. The pressure reducing valve according to claim 11, wherein the lower end of the movable iron is in a cone shape with a diameter decreasing from top to bottom, and a steel ball for sealing the oil outlet is fixedly connected to the bottom of the movable iron.