Compatible nominal voltage urea gear pump direct current brushless motor structure

Abstract

The application discloses a DC brushless motor structure compatible with a nominal voltage for a urea gear pump, which comprises a motor rotor, a stator coil, a coil framework and an isolation sheath, the stator coil is wound on the coil framework and annularly arranged on the outer ring of the motor rotor, the motor rotor is fixedly connected with a gear assembly, the isolation sheath is arranged in the air gap between the motor rotor and the stator coil, the stator coil is separated from the motor rotor, the urea solution leakage is prevented, and corrosion caused by the urea solution leakage is prevented, the side wall of the isolation sheath close to the motor rotor is provided with an anti-freezing block, and the anti-freezing block is an elastic body which is contracted under pressure and rebounds under reduced pressure. The DC brushless motor structure realizes the isolation between the motor rotor and the stator coil and the coil framework through the isolation sheath, the urea solution leakage and the corrosion caused by the urea solution leakage are prevented, and when the isolation sheath is filled with urea liquid and is in a low-temperature icing state, the anti-freezing block protects the related components from being damaged due to the urea icing expansion, the protection performance is good, and the compatibility is strong.

Description

TECHNICAL FIELD

[0001] The present application relates to a urea gear pump in an SCR system, in particular to a DC brushless motor structure compatible with nominal voltage for the urea gear pump. BACKGROUND

[0002] With the increasingly stringent regulations on diesel engine emissions, the stability, reliability, high integration and miniaturization of each component of the SCR system of the diesel engine are also increasingly demanding. Among them, the stability and reliability of the urea pump as the core component of the SCR system are also increasingly valued.

[0003] Currently, the urea pump without air assistance in the SCR system adopts the forms of urea gear pump, plunger pump and diaphragm pump. Since urea is corrosive, urea solution has a permeation and destructive effect on general sealing elements. The existing gear pump motor has insufficient protection. Once urea solution leaks into the stator and rotor, it will greatly affect the service life of the urea pump. In addition, there is a design of adding a protective sleeve to separate the urea solution. However, the volume of urea solution will increase by 10% after freezing at low temperature. When the protective sleeve is filled with urea solution and frozen at low temperature, the related components will be damaged under pressure, and the root problem has not been solved.

[0004] In addition, the existing motor is only suitable for one nominal voltage system, such as the conventional 12v nominal voltage (voltage range 9-16v) and 24v nominal voltage (voltage range 16-32v). It can only be used for one of them, and it is difficult to be compatible and has limited use. SUMMARY

[0005] Based on the above problems, the purpose of the present application is to provide a DC brushless motor structure compatible with nominal voltage for urea gear pump, improve the internal protection structure of the motor, and reduce the damage caused by the expansion of urea freezing, and improve the applicability of the motor.

[0006] To achieve the above purpose, the present application adopts the following technical scheme:

[0007] A DC brushless motor structure compatible with nominal voltage for urea gear pump is combined and assembled with a gear assembly to form a urea gear pump, which comprises a motor rotor, a stator coil, a coil skeleton and an isolation sleeve. The stator coil is wound on the coil skeleton and annularly arranged on the outer ring of the motor rotor. The motor rotor is fixedly connected with the gear assembly. The isolation sleeve is arranged in the air gap between the motor rotor and the stator coil to separate the stator coil from the motor rotor and prevent corrosion caused by urea solution leakage. The side wall of the isolation sleeve close to the motor rotor is provided with an anti-freezing block, which is an elastic body capable of being compressed and rebounded under pressure.

[0008] In particular, the elastic body is a silicon rubber with repeatable compressibility and acid-base stability.

[0009] Particularly, the line inductance, line resistance, counter electromotive force constant, pole number and square wave pulse width modulation mode of the stator coil are customized to be suitable for different nominal voltages.

[0010] Particularly, the isolation sheath is single-opening barrel-shaped and is inverted on the motor rotor, and the anti-freezing block is fixed on the barrel bottom of the isolation sheath by the fixing plate.

[0011] Particularly, the motor rotor is connected with the driving gear of the gear assembly, the driving gear is driven to rotate by the rotation of the motor rotor, the driving gear drives the driven gear of the gear assembly to rotate, and the variable-volume closed space is continuously formed in the gear assembly during the rotation process, so that the local negative pressure is formed, and the urea solution is absorbed or discharged under the action of the external atmospheric pressure.

[0012] Particularly, the motor rotor can be controlled to rotate forward or reversely, when the motor rotor rotates reversely, the urea solution is controlled to flow reversely, so that the urea gear pump is emptied.

[0013] Particularly, the structure of the direct-current brushless motor adopts a three-phase nine-winding six-pole inner rotor form.

[0014] In summary, the beneficial effects of the direct-current brushless motor structure for the urea gear pump compatible with nominal voltage are that the isolation between the motor rotor and the stator coil and the coil framework is realized by the isolation sheath, the leakage of the urea solution and the corrosion caused by the leakage are prevented, when the isolation sheath is filled with the urea liquid and is in a low-temperature ice state, the related components are protected from being damaged by the ice expansion of the urea, the protection performance is good, the installation is convenient, and in addition, the stator coil is customized with the line inductance, line resistance, counter electromotive force constant, pole number and square wave pulse width modulation mode, so that the direct-current brushless motor structure for the urea gear pump compatible with nominal voltage can be compatible with various different nominal voltage systems, and the applicability is strong. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is an assembly appearance view of the direct-current brushless motor structure for the urea gear pump compatible with nominal voltage and the gear assembly provided by the embodiment of the present application;

[0016] Figure 2 is a disassembly schematic view of the direct-current brushless motor structure for the urea gear pump compatible with nominal voltage and the gear assembly provided by the embodiment of the present application. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar parts or parts having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0018] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0019] In the description of the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first feature and the second feature are in direct contact, or that the first feature and the second feature are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0020] The technical scheme of the present application will be further illustrated by specific embodiments in combination with the drawings.

[0021] Please refer to Figure 1 and Figure 2 The preferred embodiment provides a DC brushless motor structure 100 compatible with nominal voltage for urea gear pump, which is combined and assembled with gear assembly 200 to form a urea gear pump, and includes motor rotor 110, stator coil 120, coil skeleton 130 and isolation sheath 140.

[0022] The stator coil 120 is wound on the coil skeleton 130 and annularly arranged on the outer ring of the motor rotor 110. The stator coil 120 here can adapt to two different nominal voltage systems of 12v (voltage range 9-16v) and 24v (voltage range 16-32v) through customizing parameters such as wire inductance, wire resistance, back electromotive force constant and pole number, and square wave pulse width modulation mode.

[0023] The motor rotor 110 is fixedly connected with the gear assembly 200, and the isolation sheath 140 is arranged in the air gap between the motor rotor 110 and the stator coil 120, so as to separate the stator coil 120 from the motor rotor 110 and prevent corrosion caused by urea solution leakage. The isolation sheath 140 is preferably arranged as a single-opening barrel shape and is invertedly buckled on the motor rotor 110.

[0024] In particular, the side wall of the isolation sheath 140 close to the motor rotor 110 is provided with an anti-freezing block 150, which is fixed to the barrel bottom of the isolation sheath 140 by a fixing plate 160. The anti-freezing block 150 is an elastic body that shrinks under pressure and rebounds when the pressure is reduced. The elastic body is preferably a silicon rubber that has repeatable compression and acid-base stability. The anti-freezing block 150 can effectively absorb the increased volume of the urea solution in the frozen state, thereby effectively preventing the destruction of the motor rotor 110, the stator coil 120, and the gear assembly 200 caused by the urea solution filling the inside of the isolation sheath 140 and freezing at low temperature.

[0025] The motor rotor 110 is connected to the driving gear 210 of the gear assembly 200. The driving gear 210 is driven to rotate by the motor rotor 110, and in turn drives the driven gear 220 of the gear assembly 200 to rotate. During the rotation process, a closed space with variable volume is continuously formed in the gear assembly 200, thereby forming a local negative pressure. Under the action of the external atmospheric pressure, the urea solution is sucked in or discharged. In addition, in cooperation with the overflow valve on the gear assembly 200, the pressure of the supplied urea solution is stabilized within a certain range.

[0026] The motor rotor 110 can be controlled to rotate forward or reverse. When the motor rotor 110 rotates reversely, the urea solution is controlled to flow reversely, so that the urea gear pump is emptied, thereby reducing the setting of the emptying valve. The DC brushless motor structure 100 adopts a three-phase nine-winding six-pole inner rotor form. The N-pole of the rotor has an alignment movement trend with the S-pole of the energized winding, and the S-pole of the rotor has an alignment movement trend with the N-pole of the energized winding, i.e., the S and N poles attract each other, realizing the continuous forward and reverse rotation of the rotor.

[0027] In summary, the above-mentioned DC brushless motor structure for urea gear pump compatible with nominal voltage realizes the isolation between the motor rotor and the stator coil and the coil skeleton through the isolation sheath, prevents the leakage of urea solution and the corrosion caused thereby, and protects the relevant components from being damaged by the expansion of urea freezing when the inside of the isolation sheath is filled with urea liquid and freezes at low temperature. The protection performance is good, the installation is convenient, and in addition, the stator coil can be compatible with multiple different nominal voltage systems through the customization of parameters such as wire inductance, wire resistance, counter electromotive force constant, and pole number, and the square wave pulse width modulation mode, thereby having strong applicability.

[0028] The above examples only illustrate the basic principles and characteristics of the present application. The present application is not limited by the above examples. Various changes and modifications can be made without departing from the spirit and scope of the present application. These changes and modifications fall within the scope of the present application claimed. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A DC brushless motor structure compatible with nominal voltage for a urea gear pump, which is assembled in combination with a gear assembly to form a urea gear pump, characterized by, The motor rotor, the stator coil, the coil skeleton and the isolation sheath, the stator coil is wound on the coil skeleton, and is arranged around the outer circle of the motor rotor, the motor rotor is fixed with the gear assembly, the isolation sheath is arranged in the air gap between the motor rotor and the stator coil, the stator coil is separated from the motor rotor, the corrosion caused by urea solution leakage is prevented, the side wall of the isolation sheath close to the motor rotor is provided with an anti-freezing block, the anti-freezing block is an elastic body which is compressed and shrunk, and rebounds when the pressure is reduced. The wire inductance, wire resistance, counter electromotive force constant, pole number and square wave pulse width modulation mode of the stator coil are customized to be suitable for different nominal voltages. The isolation sheath is single-opening barrel-shaped and is inverted on the motor rotor, the anti-freezing block is fixed on the bottom of the isolation sheath by the fixed plate, and the damage to the motor rotor, the stator coil and the gear assembly caused by the urea liquid filled in the isolation sheath and low-temperature icing is prevented.

2. The DC brushless motor structure for a urea gear pump compatible with a nominal voltage according to claim 1, characterized by: The elastic body is a silicon rubber with repeatable compression and acid-base stability.

3. The DC brushless motor structure for a urea gear pump compatible with a nominal voltage according to claim 1, characterized by: The motor rotor is connected with the driving gear of the gear assembly, the driving gear is driven to rotate by the rotation of the motor rotor, the driving gear drives the driven gear of the gear assembly to rotate, and the variable volume closed space is continuously formed in the gear assembly during the rotation process, so that the local negative pressure is formed, and the urea solution is absorbed or discharged under the action of the external atmospheric pressure.

4. The DC brushless motor structure for a urea gear pump compatible with a nominal voltage according to claim 1, characterized by: The motor rotor can be controlled to rotate forward or backward, when the motor rotor rotates reversely, the urea solution is controlled to flow reversely, so that the urea gear pump is emptied.

5. The DC brushless motor structure for a urea gear pump compatible with a nominal voltage according to claim 1, characterized by: The structure of the direct current brushless motor adopts a three-phase nine-winding six-pole inner rotor form.

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