阅读说明：本技术 一种活动式防冻压力开关及尿素泵 (Movable anti-freezing pressure switch and urea pump ) 是由 刘印 刘德文 曾伟 袁书华 臧志成 于 2020-05-29 设计创作，主要内容包括：本发明公开一种活动式防冻压力开关及尿素泵,该活动式防冻压力开关包括压力开关本体,压力开关本体包括基座、橡胶垫块、壳体及设置于壳体内的动触片、静触片、膜片、膜片挡板、顶杆、供电接头,基座的底部开设有底孔,橡胶垫块安装于底孔内,压力开关本体还包括有弹簧、弹簧座,基座包括座体、第一延伸座及第二延伸座,弹簧座的上端套设于壳体外,弹簧座的下端套设于座体外,弹簧设置于弹簧座的内壁与壳体的外壁之间,弹簧处于预紧状态,弹簧的上端抵靠在弹簧座顶端的内壁上,弹簧的下端抵靠在座体的上端面上。本发明通过设置弹簧,进而能够吸收因尿素泵内液体结冰膨胀而产生的作用力,避免了压力开关内膜片及挡板受力而永久变形。(The invention discloses a movable anti-freezing pressure switch and a urea pump, wherein the movable anti-freezing pressure switch comprises a pressure switch body, the pressure switch body comprises a base, a rubber cushion block, a shell, a movable contact piece, a static contact piece, a diaphragm baffle, an ejector rod and a power supply connector, the movable contact piece, the static contact piece, the diaphragm, the ejector rod and the power supply connector are arranged in the shell, a bottom hole is formed in the bottom of the base, the rubber cushion block is arranged in the bottom hole, the pressure switch body further comprises a spring and a spring seat, the base comprises a base body, a first extending seat and a second extending seat, the upper end of the spring seat is sleeved outside the shell, the lower end of the spring seat is sleeved outside the base body, the spring is arranged between the inner wall of the spring seat and the outer. The invention can absorb the acting force generated by the icing and expansion of the liquid in the urea pump by arranging the spring, thereby avoiding the permanent deformation of the diaphragm and the baffle in the pressure switch caused by the stress.)

1. The utility model provides a movable antifreeze pressure switch, includes the pressure switch body, the pressure switch body include base, rubber cushion, connect in the casing of base upper end and set up in movable contact spring, static contact, diaphragm baffle, ejector pin, power supply joint in the casing, the upper end that the power supply connects upwards stretches out outside the casing, the bottom outlet has been seted up to the bottom of base, rubber cushion install in the bottom outlet, just the through-hole has been seted up along upper and lower direction on the rubber cushion, the through-hole is linked together so that the inner chamber of pressure switch body with the inner chamber of urea pump forms intercommunication, its characterized in that: the pressure switch body still includes spring, spring holder, the base include the pedestal, connect in the first seat that extends of pedestal upper end and connect in the second of pedestal lower extreme extends the seat, the external diameter of pedestal is greater than the external diameter of casing, the upper end cover of spring holder is located outside the casing, just the lower pot head of spring holder is located outside the pedestal, the spring set up in the inner wall of spring holder with between the outer wall of casing, the spring is in pretension state, the upper end of spring support by on the inner wall on spring holder top, the lower extreme of spring support by on the up end of pedestal.

2. The movable antifreeze pressure switch of claim 1, wherein: when the urea pump is in a normal working state, the acting force generated when the liquid pressure in the urea pump is at the maximum value is smaller than the pretightening force of the spring.

3. The movable antifreeze pressure switch of claim 2, wherein: the spring has a compression margin when the urea pump is in an abnormal operating state.

4. The movable antifreeze pressure switch of claim 3, wherein: the center line of the through hole on the rubber cushion block is staggered with the center line of the circulation channel on the urea pump.

5. The movable antifreeze pressure switch of claim 1, wherein: a sealing groove is formed in the outer side face of the lower end of the base, and a sealing ring is installed in the sealing groove.

6. The movable antifreeze pressure switch of claim 1, wherein: the top end of the spring seat is provided with a sleeve hole, and the aperture of the sleeve hole is larger than the outer diameter of the shell.

7. The movable antifreeze pressure switch according to any one of claims 1 to 6, wherein: the rubber cushion block adopts a three-section reducing form to form a double-step structure, and comprises a first cylindrical section, a second cylindrical section and a third cylindrical section, wherein the radius of the first cylindrical section, the second cylindrical section and the third cylindrical section are sequentially reduced from bottom to top, the bottom hole is corresponding to two sections of reducing holes, the rubber cushion block is arranged at the bottom hole, the step surface of the first cylindrical section is tightly attached to and abutted against the bottom end of the base, and the step surface of the second cylindrical section is tightly attached to and abutted against the step in the bottom hole.

8. The movable antifreeze pressure switch of claim 7, wherein: the diameter of the third cylindrical section is d, d is more than 4mm and less than 6mm, and the axial length of the third cylindrical section is not less than 2 mm.

9. The movable antifreeze pressure switch of claim 8, wherein: the bottom end of the first cylindrical section is provided with a cross arc-shaped groove, the cross arc-shaped groove is positioned under the through hole, and the cross arc-shaped groove is communicated with the through hole.

10. A urea pump, characterized by: comprising a movable antifreeze pressure switch according to any of claims 1 to 9.

Technical Field

The invention relates to the technical field of selective catalytic conversion of diesel engines, in particular to a movable anti-freezing pressure switch and a urea pump.

Background

Nitrogen oxide (NOx) contained in the exhaust gas discharged from diesel engines causes serious pollution to the atmospheric environment, and directly affects the ecological environment and human health. At present, the tail gas treatment of the diesel engine is mainly realized by a Selective Catalytic Reduction (SCR) system, and the system needs to atomize and quantitatively spray a standard urea solution for vehicles into an exhaust pipe by a urea pump, and catalytically reduce NOx into harmless nitrogen and water by a catalyst to realize the purpose of tail gas treatment.

The existing urea pump is easy to break down in cold climate areas (lower than-11 ℃), because the urea pump does not work for a long time, the residual urea solution in the urea pump freezes and expands in a low temperature environment, while the pressure switch in the existing urea pump controls the contact and separation between the action contact piece and the static contact piece in the pressure switch by utilizing the positive and negative bounce of the membrane, and under the low temperature environment, the inner membrane and the baffle of the pressure switch are subjected to the freezing and expanding force of liquid, so that the pressure switch is easy to permanently deform, the action contact piece and the static contact piece of the pressure switch are permanently separated and lose efficacy, and the urea pump breaks down.

The above problems seriously affect the working stability of the urea pump and the normal running of the vehicle, and become a technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

The invention aims to solve the problems and provide a movable anti-freezing pressure switch and a urea pump to solve the problem that the urea pump in the prior art is easy to damage an internal pressure switch in a low-temperature environment.

The purpose of the invention is realized by the following technical scheme:

a movable anti-freezing pressure switch comprises a pressure switch body, wherein the pressure switch body comprises a base, a rubber cushion block, a shell connected to the upper end of the base, and a movable contact piece, a static contact piece, a membrane baffle, a push rod and a power supply connector which are arranged in the shell, the upper end of the power supply connector upwards extends out of the shell, the bottom of the base is provided with a bottom hole, the rubber cushion block is arranged in the bottom hole, a through hole is formed in the rubber cushion block along the vertical direction, the through hole is communicated with a circulation channel of a urea pump so that an inner cavity of the pressure switch body is communicated with the inner cavity of the urea pump, the pressure switch body further comprises a spring and a spring seat, the base comprises a seat body, a first extending seat connected to the upper end of the seat body and a second extending seat connected to the lower end of the seat body, and, the upper end cover of spring holder is located outside the casing, just the lower pot head of spring holder is located outside the pedestal, the spring set up in between the inner wall of spring holder and the outer wall of casing, the spring is in pretension state, the upper end of spring support to lean on the inner wall on spring holder top, the lower extreme of spring support to lean on the up end of pedestal.

In a preferred embodiment of the present invention, when the urea pump is in a normal operating state, an acting force generated when a liquid pressure in the urea pump is at a maximum value is smaller than a pre-tightening force of the spring.

In a preferred embodiment of the present invention, the spring has a compression margin when the urea pump is in an abnormal operation state.

In a preferred embodiment of the present invention, a center line of the through hole in the rubber mat is offset from a center line of the flow channel in the urea pump.

As a preferable scheme of the present invention, a sealing groove is formed on an outer side surface of a lower end of the base, and a sealing ring is installed in the sealing groove.

As a preferable scheme of the invention, a sleeving hole is formed at the top end of the spring seat, and the aperture of the sleeving hole is larger than the outer diameter of the shell.

As a preferred scheme of the invention, the rubber cushion block adopts a three-section reducing form to form a double-step structure, and comprises a first cylindrical section, a second cylindrical section and a third cylindrical section, wherein the radius of the first cylindrical section, the second cylindrical section and the third cylindrical section is sequentially reduced from bottom to top, two sections of reducing holes are arranged corresponding to the bottom hole, when the rubber cushion block is arranged in the bottom hole, the step surface of the first cylindrical section is tightly attached to and abutted against the bottom end of the base, and the step surface of the second cylindrical section is tightly attached to and abutted against the step in the bottom hole.

In a preferred embodiment of the present invention, the diameter of the third cylindrical section is d, 4mm < d < 6mm, and the axial length of the third cylindrical section is not less than 2 mm.

As a preferable scheme of the present invention, a cross arc-shaped groove is formed at a bottom end of the first cylindrical section, the cross arc-shaped groove is located right below the through hole, and the cross arc-shaped groove is communicated with the through hole.

A urea pump comprising a movable antifreeze pressure switch as described above.

The movable anti-freezing pressure switch has the advantages that the spring is arranged, so that acting force generated by freezing and expansion of liquid in the urea pump can be absorbed, permanent deformation of the diaphragm and the baffle in the pressure switch due to stress is avoided, in addition, the rubber cushion block is arranged, acting force generated by freezing and expansion of the liquid at the diaphragm in the pressure switch can be absorbed, and therefore the functionality of the pressure switch is effectively guaranteed. Not only the structure is simple, but also the design is ingenious; and the cost is low, and the safe and stable operation of the urea pump at low temperature is ensured.

Drawings

FIG. 1 is a schematic diagram of a movable antifreeze pressure switch;

fig. 2 is a schematic sectional view of a movable antifreeze pressure switch.

In the figure:

1. a base; 2. a rubber cushion block; 3. a housing; 4. a spring; 5. a spring seat; 6. a movable contact spring; 7. a static contact piece; 8. a membrane; 9. a diaphragm baffle; 10. a top rod; 11. a power supply connector 12 and a urea pump; 13. a flow-through channel; 14. a seal ring; 15. and a through hole.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings. It is to be understood that the embodiments described herein are illustrative only and are not limiting upon the present invention.

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of a movable anti-freezing pressure switch; fig. 2 is a schematic sectional view of a movable antifreeze pressure switch.

In this embodiment, a movable anti-freezing pressure switch comprises a pressure switch body, wherein the pressure switch body comprises a base 1, a rubber cushion block 2, a shell 3 connected to the upper end of the base 1, and a movable contact piece 6, a static contact piece 7, a membrane 8, a membrane baffle 9, a top rod 10 and a power supply connector 11 arranged in the shell 3, the upper end of the power supply connector 11 upwards extends out of the shell 3, the bottom of the base 1 is provided with a bottom hole, the rubber cushion block 2 is arranged in the bottom hole, the rubber cushion block 2 is provided with a through hole 15 along the up-down direction, the aperture of the through hole 15 is not more than 1.5mm, the through hole 15 is communicated with a circulation channel 13 of a urea pump 12 so that the inner cavity of the pressure switch body is communicated with the inner cavity of the urea pump 12, the pressure switch body further comprises a spring 4 and a spring seat 5, the base 1 comprises a base body, a first extension seat connected to the upper end of the base body and a second extension seat connected to the lower end of the base body, the outer diameter of the base body is larger than the outer diameter of the shell 3, the upper end of the spring seat 5 is sleeved outside the shell 3, the lower end of the spring seat 5 is sleeved outside the base body, the spring 4 is arranged between the inner wall of the spring seat 5 and the outer wall of the shell 3, the spring 4 is in a pre-tightening state, the upper end of the spring 4 is abutted against the inner wall of the top end of the spring seat 5, and the lower end of the spring 4 is abutted against the upper end face of the base body.

Specifically, in this embodiment, when the urea pump 12 is in a normal operating state, an acting force generated when the liquid pressure in the urea pump 12 is at a maximum value is smaller than the pre-tightening force of the spring 4.

Specifically, in the present embodiment, when the urea pump 12 is in an abnormal operation state, the spring 4 has a compression margin, and the compression margin of the spring 4 is 3 mm.

Specifically, the center line of the through hole 15 on the rubber cushion block 2 is staggered with the center line of the circulation channel 13 on the urea pump 12, in this embodiment, the center line of the through hole 15 on the rubber cushion block 2 is staggered with the center line of the circulation channel 13 on the urea pump 12 by 2.8mm, so that more acting force generated by the expansion of ice in the urea pump 12 acts on the base 1 of the pressure switch body.

In order to prevent liquid in the urea pump 12 from overflowing, a sealing groove is formed in the outer side face of the lower end of the base 1, a sealing ring 14 is installed in the sealing groove, and the distance between the sealing ring 14 and the installation combination surface of the urea pump 12 and the pressure switch body is larger than 8 mm.

In this embodiment, the top of spring holder 5 is opened and is cup jointed the hole, the aperture that cup joints the hole is greater than the external diameter of casing 3, not only is convenient for install, and when guaranteeing that pressure switch body bottom is frozen, this physical stamina of pressure switch rises upwards through cup jointing the hole.

In the embodiment, the rubber cushion block 2 adopts a three-section reducing form to form a double-step structure, and comprises a first cylindrical section, a second cylindrical section and a third cylindrical section, wherein the radius of the first cylindrical section, the second cylindrical section and the third cylindrical section is sequentially reduced from bottom to top, two sections of reducing holes are formed corresponding to the bottom hole, when the rubber cushion block 2 is arranged in the bottom hole, the step surface of the first cylindrical section is tightly attached to and abutted against the bottom end of the base 1, and the step surface of the second cylindrical section is tightly attached to and abutted against the step in the bottom hole; the double-step structure blocks the axial stress from being transmitted to the diaphragm 8 on the one hand, avoids the diaphragm 8 from being pressed, and on the other hand prevents the rubber cushion block 2 from being stressed to move towards the inside of the bottom hole and extruding the diaphragm 8, so that the pressure switch body is abnormal.

In this embodiment, the diameter of the third cylindrical section is d, d is greater than 4mm and less than 6mm, and the axial length of the third cylindrical section is not less than 2 mm; by adopting the structural design, the strength of the head part of the rubber cushion block 2 is weaker, and the rubber cushion block 2 is easily compressed and deformed to absorb the volume change of the frozen inner cavity when the liquid remained in the pressure switch body is frozen.

In this embodiment, a cross arc-shaped groove is formed at the bottom end of the first cylindrical section, the cross arc-shaped groove is located right below the through hole 15, and the cross arc-shaped groove is communicated with the through hole 15; thereby increasing the pressure-bearing area and realizing the circulation of liquid; and one side of the cross arc-shaped groove structure is directly attached to the urea pump 12, so that the rubber cushion block 2 is prevented from moving towards the direction of the flow channel 13 corresponding to the urea pump 12.

When the urea pump 12 works in a low-temperature environment (lower than-11 ℃), the liquid freezes and expands, the pressure switch body and the rubber cushion block 2 are integrally lifted, or the pressure switch body is lifted, the rubber cushion block 2 is not lifted, or the pressure switch body and the rubber cushion block 2 are separated in the process of lifting together, and the three conditions can play a role in protecting the pressure switch body diaphragm 8. Specifically, the acting force generated by the freezing and expansion of the liquid in the urea pump 12 is mainly absorbed by the compression of the spring 4; when liquid at the membrane 8 in the pressure switch body is frozen and expands, the head of the rubber cushion block 2 is compressed and deformed, so that the volume of the cavity at the membrane 8 is increased to reduce the frozen expansion force.

When the bottom of the pressure switch body is frozen, the pressure switch body and the rubber cushion block 2 are lifted together, or the pressure switch body is separated from the rubber cushion block 2; however, when the internal cavity of the pressure switch body is frozen, the pressure switch body and the rubber cushion block 2 are possibly separated relatively in the lifting process or after being lifted, and the two separation modes can reduce the stress of the diaphragm 8 of the pressure switch body, so that the pressure switch body is protected.

At normal temperature, because the pretightening force of the spring 4 is greater than the working starting pressure of the pressure switch body, when the urea pump 12 works normally, the rubber cushion block 2 and the pressure switch body are both kept in a static state, and the performance of the urea pump 12 is not affected.

The embodiment also discloses a urea pump which comprises the movable anti-freezing pressure switch.

The foregoing embodiments are merely illustrative of the principles and features of this invention, which is not limited to the above-described embodiments, but rather is susceptible to various changes and modifications without departing from the spirit and scope of the invention, which changes and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims.