CN214464721U - Oscillating disc type variable displacement pump - Google Patents

Abstract

A wobble plate type positive displacement pump comprises a shell, a liquid inlet, a liquid outlet and a wobble plate structure. The tray arranging mechanism comprises a rotating shaft, a cantilever and a pressing plate, the pressing plate comprises a flat plate and an elastic element, the shell comprises a guide groove and a boss, the boss is arranged between the liquid inlet and the liquid outlet, the elastic element is arranged in the guide groove, a seal is formed between the boss and the elastic element, and the guide groove is matched with the side wall of the elastic element to form a liquid flow channel. The purpose of this scheme is to provide a simple structure, operate steadily, with low costs, and have the wobble plate positive displacement pump of pumpback function.

Description

Oscillating disc type variable displacement pump

Technical Field

The invention belongs to the technical field of liquid metering injection, in particular relates to a liquid injection metering technology related to an engine, and particularly relates to a NOx Selective Catalytic Reduction (SCR) system for purifying tail gas of the engine.

Background

The liquid injection system has wide application in the fields of chemical engineering, medical treatment, power machinery and the like, and particularly relates to a plurality of core technologies of internal combustion power.

Today, internal combustion engine powered vehicles require better combustion control and exhaust after treatment systems are installed in an attempt to meet increasingly stringent emission requirements. For example, engines including spark ignition small engines also employ an electronic fuel injection technique and an exhaust gas three-way catalytic treatment technique like automobile engines; in order to reduce harmful pollutants in exhaust gas, a diesel engine or a lean-burn direct injection gasoline engine adopts a NOx Selective Catalytic Reduction (SCR = Selective Catalytic Reduction) technology capable of performing Catalytic Reduction treatment in an oxygen-rich environment for NOx pollutants.

All these technologies, which involve the problem of liquid supply and dosing, require the injection of a NOx selective reducing agent, such as a 32.5% by weight urea aqueous solution, upstream of the SCR catalyst (also called Diesel Exhaust Fluid DEF = Diesel Exhaust Fluid, or additive blue Fluid).

Due to the characteristics of the urea aqueous solution, after the injection is finished, the urea mixed solution remained in the closed urea system and the pipeline is likely to freeze below the freezing point (-11-12 ℃) of the urea solution, which not only can cause the urea injection to be interrupted, but also can cause the urea injection system to be damaged due to the expansion of the urea solution during the freezing. In the existing SCR technology, an auxiliary heating device is mostly considered to be additionally arranged to ensure the normal work of a system. However, the existing devices for providing a source of injection power are too bulky or otherwise difficult to integrate system components into the DEF reservoir, often requiring complex design of ice melting devices, which makes the system more bulky and difficult to deploy, and at the same time, the more complex the system, the higher the cost. Especially for the built-in injection system of urea pump, the urea pump is arranged and is often pressed close to the bottom of the box, and self does not have the ability of unfreezing, needs the system of thoroughly unfreezing just can begin to work, leads to the system all to receive the restriction on unfreezing time and arrangement space.

For example, US20090301067a1 discloses a metered spray device and method. The metering injection device is a solenoid-driven plunger pump nozzle arranged on an exhaust pipe, needs an additional low-pressure pump to provide working liquid for the metering injection device from a DEF (DEF) liquid storage tank, and cannot work normally without the assistance of a special ice melting and nozzle cooling device.

In addition, PCT entered chinese patent CN 106662102B discloses a rotary pump for delivering exhaust purification additives, which adopts a cam structure, and can evacuate residual urea solution in the pipeline by utilizing the pumping capacity of the pump itself, the pump has the advantages of compact structure, small volume, easy arrangement, stable operation, etc., but the pump structure adopts an annular rubber element as a liquid track, and achieves the delivery of liquid by a way of generating directional fluid through the movement of the cam, so that the requirements on the process and precision of the parts themselves are high, and the system cost is increased.

Disclosure of Invention

The present application is directed to the above-mentioned problem, and its object is to provide a wobble plate type positive displacement pump with simple structure, stable operation, low cost, and having the function of pumping back.

In order to achieve the purpose, the invention adopts the following technical scheme: a wobble plate type positive displacement pump comprises a shell, at least one liquid inlet, at least one liquid outlet and a wobble plate mechanism.

The liquid inlet and the liquid outlet are arranged on the shell. The wobble plate mechanism comprises a rotating shaft, a cantilever and a pressing plate. The pressing plate comprises a flat plate and an elastic element, wherein the flat plate and the elastic element are relatively fixed and can be designed into a whole through injection molding and the like.

The shell comprises a guide groove, a boss and a central shaft, the boss is arranged between the liquid inlet and the liquid outlet, the elastic element can be a sealing element, such as a rubber element, can be an annular structure with a rectangular cross section, and is matched with the guide groove structure. The elastic element is arranged in the guide groove and presses the boss, so that sealing is formed between the boss and the elastic element. Meanwhile, the guide groove is matched with the side wall of the elastic element to form a sealed space, a liquid flow channel is formed between the groove body of the guide groove and the bottom surface of the elastic element, and the boss prevents liquid from directly flowing out of the liquid outlet without passing through the liquid flow channel.

The top of the central shaft comprises a spherical surface, the center of the pressure plate comprises a spherical groove matched with the spherical surface, and the pressure plate is arranged on the central shaft, so that the spherical surface falls in the spherical groove to reduce the resistance and abrasion of the pressure plate during swinging.

The rotating shaft and the pressing plate are coaxially arranged, one end of the cantilever is fixed to the rotating shaft, a roller of the rotor is arranged at the other end of the cantilever, and the roller is tightly attached to the pressing plate and enables the pressing plate to be stressed to be attached to the upper end face of the guide groove.

When the rotating shaft moves, the cantilever performs synchronous circular motion around the rotating shaft and drives the roller to roll on the pressure plate, a certain movable gap is formed between the pressure plate and the shell, the gap between the pressure plate and the shell is not smaller than the section height of the liquid flow channel, the pressure plate is pressed downwards and inclined at the position where the roller is in contact with the pressure plate to drive the elastic element to move downwards, the bottom of the elastic element is tightly attached to the guide groove to divide the liquid flow channel into a liquid inlet cavity and a liquid outlet cavity, and the volumes of the liquid inlet cavity and the liquid outlet cavity are changed alternately along with the periodic change of the distance between the roller and the boss.

Further, for guaranteeing the stable operation and the durability, the guide groove and the roller are designed by adopting the motion characteristics of the attached flat plate. The top surface of the guide groove comprises a wedge-shaped surface with the same inclination angle as the pressure plate, so that the inner channel plane in contact with the flat plate is higher than the outer channel plane. The roller is a cone with the same inclination angle as the pressing plate, so that the roller is ensured to be in line contact with the plane of the pressing plate.

The wobble plate type positive displacement pump further comprises a driving motor, wherein the driving motor can be selectively arranged on the rotating shaft and can also be selectively packaged in the shell to reduce the overall dimension, and the rotating shaft is driven to move by the action of the driving motor.

The wobble plate type positive displacement pump can be applied to an SCR (selective Catalytic reduction) system. The SCR system comprises an exhaust aftertreatment device with an SCR catalyst, and the exhaust aftertreatment device supplies aftertreatment solution to the SCR catalyst by using the wobble plate positive displacement pump to perform exhaust treatment. After the post-treatment is finished, residual liquid in the pipeline can be pumped back in a mode of driving the motor to rotate reversely, so that the system is prevented from being damaged by freezing when the liquid is at low temperature.

The following technical solutions further define or optimize the present application.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a wobble plate type positive displacement pump provided in the present invention.

Fig. 2 is a schematic diagram of the structure of the liquid inlet and the liquid outlet of the wobble plate type positive displacement pump provided by the present invention.

Fig. 3 is a schematic diagram of a motion state of the wobble plate type positive displacement pump provided by the present invention.

Detailed Description

The invention is further described below with reference to the figures and examples.

The structure schematic diagram of the embodiment of the wobble plate type positive displacement pump and the structure schematic diagrams of the liquid inlet and the liquid outlet 13 thereof provided by the application are shown in fig. 1 and fig. 2, the wobble plate type positive displacement pump includes a housing 14, a liquid inlet 11, a liquid outlet 13 and a wobble plate mechanism 1, liquid enters from the liquid inlet 11, and the liquid is driven to be output from the liquid outlet 13 through the directional movement of the wobble plate mechanism 1.

The wobble plate mechanism 1 includes a rotating shaft 17, a suspension arm 19, and a pressure plate 16. The pressure plate 16 comprises a flat plate 20 and an elastic element 15, and the flat plate 20 and the elastic element 15 are designed as a whole.

The housing 14 includes a guiding groove 10 and a boss 12, the boss 12 is disposed between the liquid inlet 11 and the liquid outlet 13, and the elastic element 15 is a sealing member with a rectangular cross section and a ring structure, and the structure of the sealing member is matched with the guiding groove 10. The elastic member 15 is disposed in the guide groove 10 and presses the boss 12 so that a seal is formed between the boss 12 and the elastic member 15 (as shown in fig. 2).

The rotating shaft 17 is arranged coaxially with the pressure plate 16, and one end of the cantilever 19 is fixed to the rotating shaft 17 and the other end is provided with a roller 18 which can rotate relative to the cantilever 19. The rollers 18 abut the pressure plate 16 and force the pressure plate 16 against the upper end face of the guide groove 10.

As shown in fig. 3, for a schematic view of one of the motion states of the wobble plate type positive displacement pump provided by the present invention, the housing 14 includes a central shaft 52, the top of the central shaft 52 includes a spherical surface 52a, the center of the pressure plate 16 includes a spherical groove 20a matching with the spherical surface 52a, and the pressure plate 16 is mounted on the central shaft 52 such that the spherical surface 52a falls into the spherical groove 20a to reduce the resistance and wear of the pressure plate 16 during the wobble motion.

Meanwhile, the elastic element 15 is installed into the guide groove 10 along with the pressing plate 16, the guide groove 10 is matched with the side wall 10a of the elastic element 15 to form a sealed space, and the groove body of the guide groove 10 and the elastic element 15 form a liquid flow channel 50. The liquid inlet 11 and the liquid outlet 13 are disposed on the housing 14 and are communicated with the liquid flow passage 50, and the boss 12 is used to prevent the liquid from directly flowing out of the liquid outlet 13 without passing through the liquid flow passage 50.

The wobble plate type variable displacement pump further comprises a driving motor 2, wherein the driving motor 2 is packaged in the shell 14 and used for driving the rotating shaft 17 to move.

When the rotating shaft 17 moves, the cantilever 19 performs synchronous circular motion around the rotating shaft 17 and drives the roller 18 to roll on the pressure plate 16, a certain movable gap exists between the pressure plate 16 and the shell 14, the gap between the pressure plate 16 and the shell 14 is not smaller than the cross-sectional height of the liquid flow channel 50, the pressure plate 16 is pressed downwards and inclined at the position where the roller 18 contacts the pressure plate 16, the elastic element 15 is driven to move downwards, the bottom of the elastic element 15 is tightly attached to the guide groove 10 to divide the liquid flow channel 50 into a liquid inlet cavity and a liquid outlet cavity, and the volumes of the liquid inlet cavity and the liquid outlet cavity are changed alternately along with the periodic change of the distance between the roller 18 and the boss 12.

Further, in order to ensure smooth operation and durability, the guide groove 10 and the roller 18 are designed to fit the motion characteristics of the flat plate 20. The top surface of the guide channel 10 includes a wedge surface 51 inclined at the same angle as the platen 16 so that the inner track plane in contact with the plate 20 is higher than the outer track plane. The roller 18 is a cone with the same inclination angle as the pressure plate 16, so as to ensure that the roller 18 is in line contact with the plane of the pressure plate 16.

The above examples are only for illustrating the essence of the present invention, but not for limiting the present invention. Any modifications, simplifications, or other alternatives made without departing from the principles of the invention are intended to be included within the scope of the invention.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.

Claims (7)

1. A wobble plate type positive displacement pump comprises a shell, a liquid inlet and a liquid outlet, and is characterized by further comprising a wobble plate mechanism, wherein the wobble plate mechanism comprises a rotating shaft, a cantilever and a pressing plate, the pressing plate comprises a flat plate and an elastic element, the shell comprises a guide groove and a boss, the boss is arranged between the liquid inlet and the liquid outlet, the elastic element is arranged in the guide groove, a seal is formed between the boss and the elastic element, the guide groove is matched with the side wall of the elastic element to form a liquid flow channel,

the rotary shaft and the pressing plate are coaxially arranged, one end of the cantilever is fixed on the rotary shaft, the other end of the cantilever is provided with a roller of the rotor, the roller is tightly attached to the pressing plate, when the rotary shaft moves, the cantilever synchronously performs circular motion and drives the roller to roll on the pressing plate, a certain movable gap exists between the pressing plate and the shell, the gap between the pressing plate and the shell is not smaller than the section height of the liquid flow channel, the roller is in contact with the pressing plate, the pressing plate is pressed down to drive the elastic element to move downwards, the bottom of the elastic element is tightly attached to the guide groove to divide the liquid flow channel into a liquid inlet cavity and a liquid outlet cavity, and the volumes of the liquid inlet cavity and the liquid outlet cavity are alternatively changed along with the periodic change of the distance between the roller and the boss.

2. The wobble plate positive displacement pump of claim 1, wherein the housing includes a central shaft, the pressure plate being mounted on the central shaft.

3. The wobble plate positive displacement pump of claim 2, wherein the top of the central shaft includes a spherical surface and the center of the pressure plate includes a spherical groove that mates with the spherical surface, the spherical surface being seated within the spherical groove to reduce resistance and wear of the pressure plate during oscillation.

4. The wobble plate positive displacement pump of claim 1, wherein the resilient member is a seal member fixed to the pressure plate, fixed relative to the pressure plate, having a cross-sectional shape corresponding to a cross-sectional shape of the guide groove, and cooperating with the guide groove to form a sealed space.

5. The wobble plate positive displacement pump of claim 4, wherein the top surface of the guide groove includes a wedge surface inclined at the same angle as the pressure plate.

6. The wobble plate positive displacement pump of claim 1, wherein the roller is a cone having the same angle of inclination as the platen, ensuring that the roller is in line contact with the platen plane.

7. Wobble plate positive displacement pump according to any of claims 1 to 6, comprising a drive motor, which is mounted inside the housing, the force of the drive motor being used to drive the shaft in motion.

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