High-speed low-pressure shaft-seal-free electric internal gear pump for aviation

Abstract

The invention discloses a high-speed low-voltage shaft-seal-free electric internal gear pump for aviation, which comprises a three-phase alternating-current motor and a cycloid internal gear pump matched with the three-phase alternating-current motor, and is characterized in that a rotating shaft of the three-phase alternating-current motor and a driving shaft of the cycloid internal gear pump are of a coaxial structure, and the coaxial structure is an inner shaft; the pump cavity and the motor cavity are communicated with each other, so that hydraulic oil in the pump cavity enters the inner cavity of the motor, returns to the pump cavity and is discharged through the pump. The weight of the device is reduced, the whole device has no oil leakage risk, and the motor is cooled at any time in the working process.

Description

Technical Field

[0001] The invention relates to a hydraulic pump technology for an aviation lubricating oil system, in particular to a high-speed, low-pressure, shaft-seal-free electric internal gear pump for aviation. Background Art

[0002] At present, electrification is an inevitable trend in aircraft hydraulic systems. It can not only reduce mechanical transmission mechanisms, but also has important significance for reducing aircraft pipelines. As a branch of aircraft pump sources, electric pumps provide a new option for the electrification of aircraft hydraulic systems. Electric pumps are energy components of aircraft hydraulic systems. They are devices that convert electrical energy into hydraulic energy. Their function is to provide the system with oil of a certain pressure and flow rate. In existing high-speed and low-pressure electric pumps for aviation, the pumps mainly use plunger pumps. The motor transmits torque to the plunger pump output flow through a transmission mechanism. There are large quality problems, and the pump shaft tail has a shaft tail seal structure with the risk of oil leakage. Therefore, there is a need for a new aviation-use shaft seal-free electric internal gear pump that has no oil leakage risk while ensuring the output flow pressure and can reduce the mass of the electric pump.

[0003] However, the disclosed internal gear pump structure cannot meet this requirement. For example, the patent publication number is CN107387406A, an internal gear pump, including a housing assembly, having an inner cavity; a permanent magnet DC motor is arranged in the inner cavity, and the shaft of the permanent magnet DC motor can rotate relative to the housing assembly; the inner rotor is fixed to one end of the shaft and can rotate with the shaft; the outer rotor is arranged in the inner cavity and sleeved on the outer periphery of the inner rotor; the motor wiring assembly is connected to the permanent magnet DC motor, and the motor wiring assembly can adjust the speed of the permanent magnet DC motor according to the load of the internal gear pump. This structure has relatively low application requirements. As the oil replenishment pump of the heart of commercial air conditioners, it is mainly to avoid the waste of the motor output itself and solve the problem of autonomously adjusting the oil pump displacement due to changes in oil flow with load. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and to provide a high-speed, low-pressure, sealless electric internal gear pump for aviation, which has the characteristics of reducing the weight of the electric pump and eliminating the risk of oil leakage.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions: a high-speed, low-pressure, seal-free electric internal gear pump for aviation, comprising a three-phase AC motor and a cycloid internal gear pump matched with the three-phase AC motor, characterized in that the rotating shaft of the three-phase AC motor and the driving shaft of the cycloid internal gear pump are coaxial structures, and the coaxial structure is an inner shaft.

[0006] The inner shaft is a hollow shaft, and the pump cavity and the motor cavity are connected to each other, so that the hydraulic oil in the pump cavity enters the inner cavity of the motor and returns to the pump cavity and is discharged through the pump.

[0007] In the aforementioned high-speed, low-pressure, shaft-seal-free electric internal gear pump for aviation, preferably, the pump housing of the cycloid internal gear pump and the motor housing of the three-phase AC motor form a radial sealing structure.

[0008] In the aforementioned high-speed, low-pressure, shaft-seal-free electric internal gear pump for aviation, preferably, the inner shaft is open at the shaft tail end of the cycloid internal gear pump without a seal structure.

[0009] In the aforementioned high-speed, low-pressure, sealless electric internal gear pump for aviation, preferably, an intermediate disk is provided between the three-phase AC motor and the cycloid internal gear pump, the intermediate disk and the motor casing constitute the internal component space of the three-phase AC motor, and the intermediate disk and the pump casing constitute the internal component space of the cycloid internal gear pump.

[0010] In the aforementioned high-speed, low-pressure, sealless electric internal gear pump for aviation, preferably, the inner shaft is supported and positioned by a graphite bearing in the three-phase AC motor, one end of the inner shaft is connected to the inner rotor in the cycloid internal gear pump, meshes with the inner rotor to form an outer rotor, and cooperates with the outer rotor to form an eccentric cylinder.

[0011] In the aforementioned high-speed, low-pressure, sealless electric internal gear pump for aviation, preferably, one end of the inner shaft is connected to the inner rotor of the cycloid internal gear pump, and a first pressure plate and a second pressure plate are respectively provided on both sides of the inner rotor, and both the first pressure plate and the second pressure plate are provided with through holes that cooperate with the inner shaft.

[0012] In the aforementioned high-speed, low-pressure, shaft-seal-less electric internal gear pump for aviation, preferably, the mating surfaces of the intermediate disk and the pump housing are provided with a plurality of sealing rings.

[0013] In the aforementioned high-speed, low-pressure, sealless electric internal gear pump for aviation, preferably, the power line of the three-phase AC motor is led out through a sintered terminal.

[0014] This technical solution is designed to address the problems of heavy electric pumps in aircraft hydraulic systems and the risk of oil leakage at the pump shaft tail due to the multi-component sealing structure. The entire pump body is mainly composed of a three-phase AC motor and a cycloid internal gear pump. The motor and hydraulic pump adopt a coaxial design, which reduces the intermediate transmission mechanism and has a positive significance for weight reduction. The traditional shaft tail mechanical seal between the motor and the hydraulic pump is eliminated, and a radial seal is designed between the motor and the hydraulic pump to achieve double sealing insurance and eliminate the risk of oil leakage.

[0015] Since the motor will generate power loss during operation and convert electrical energy into heat energy, the accumulation of heat energy will affect the working performance of the motor. In this solution, there is no physical isolation between the inner cavity of the motor and the pump cavity. The hydraulic oil in the pump cavity will enter the inner cavity of the motor and return to the pump cavity to be discharged through the pump. In this way, the heat generated by the motor will be conducted out through the hydraulic oil, thereby achieving a cooling effect.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The hydraulic pump adopts a cycloid internal gear pump, which has the advantage of reducing the weight of the device under the condition of low pressure and same flow.

[0018] 2. The intermediate transmission mechanism is eliminated, and the motor and hydraulic pump are designed to be coaxial, which further reduces the weight of the device.

[0019] 3. There is no shaft tail sealing device at the hydraulic pump shaft tail. The pump shaft tail seal is designed as a double-pass radial seal between the pump and the motor. The entire device has no risk of oil leakage and can reduce weight.

[0020] 4. The pump cavity is connected to the inner cavity of the motor. The heat generated by the power loss of the motor can be taken away by the oil, thereby cooling the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the appearance structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0023] Figure 3 The present invention is a schematic diagram of the radial cross-sectional structure of the cycloid internal meshing gear pump.

[0024] Figure 4 yes Figure 2 Schematic diagram of the partially enlarged structure of the cycloid internal gear pump.

[0025] In the figure: 1-three-phase AC motor; 2-countersunk screw; 3-hexagonal bolt; 4-cycloid internal gear pump; 5-first graphite bearing; 6-stator assembly; 7-rotor assembly; 8-sintered terminal; 9-second graphite bearing; 10-first pressure plate; 11-second pressure plate; 12-pump housing; 13-multi-pass sealing ring; 14-inner shaft; 15-motor housing; 16-eccentric cylinder; 17-pin; 18-outer rotor; 19-inner rotor; 20-intermediate disk. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0027] This embodiment is a high-speed, low-pressure, sealless electric internal gear pump for aviation, such as Figure 1 As shown, it includes a three-phase AC motor 1 and a cycloid internal gear pump 4 matched with the three-phase AC motor 1, wherein one end of the motor housing 15 of the three-phase AC motor 1 is connected to the pump housing 12 of the cycloid internal gear pump 4 through a flange connection by a countersunk screw 12.

[0028] In particular, the motor housing 15 and the pump housing 12 share the intermediate disk 20. That is, the intermediate disk is both a part of the motor housing 15 and a part of the pump housing 12. Generally, since the volume of the cycloid internal gear pump 4 is smaller than the motor 1, the pump housing 12 is first connected to the intermediate disk 20 by the hexagonal bolts 3 through the flange connection form, and then the intermediate disk 20 is connected to the motor housing 15 through the countersunk screws 12, so that the motor housing 15 and the pump housing 12 form a complete whole.

[0029] The complete integrated structure is further embodied by the fact that the rotating shaft of the three-phase AC motor 1 and the driving shaft of the cycloid internal meshing gear pump 4 are coaxial structures, and the coaxial structure is an inner shaft 14, such as Figure 2 shown.

[0030] Specifically, the inner shaft 14 is a hollow shaft, so that the pump cavity and the motor cavity are connected to each other. The motor cavity mentioned here refers to the internal area of ​​the motor 1 reached by the inner shaft 14, including the bearings and other parts, and is not the working space of the stator assembly 6 and the rotor assembly 7. As a result, the hydraulic oil in the pump cavity can enter the inner cavity of the motor 1 at any time during the working process, and return to the pump cavity to be discharged through the pump, thereby cooling the motor 1, especially cooling the bearings and other parts where heat is concentrated.

[0031] According to the above complete integrated structure, the inner shaft 14 is open at the shaft tail end of the cycloid internal gear pump 4 without a sealing structure, while the pump housing 12 of the cycloid internal gear pump 4 and the motor housing 15 of the three-phase AC motor 1 form a radial sealing structure. Furthermore, since an intermediate disk 20 is provided between the three-phase AC motor 1 and the cycloid internal gear pump 4, the intermediate disk 20 and the motor housing 15 constitute the internal component space of the three-phase AC motor 1, and the intermediate disk 20 and the pump housing 12 constitute the internal component space of the cycloid internal gear pump 4. The intermediate disk 20 is provided with a cylindrical mating surface on the side facing the cycloid internal gear pump 4, and the pump housing 12 has a housing inner hole that matches the cylindrical mating surface, and a double-pass sealing ring 13 is provided at the mating surface. Figure 4 As shown, the end surface of the intermediate disk 20 located in the pump housing 12 constitutes a part of the cycloid internal gear pump 4 .

[0032] Furthermore, the inner shaft 14 is supported and positioned by a graphite bearing in the three-phase AC motor 1, wherein one end of the inner shaft 14 is positioned on the motor housing 15 by a first graphite bearing 5, and the other end passes through the intermediate disk 20 to connect to the inner rotor 19 in the cycloid internal meshing gear pump 4, and a second graphite bearing 9 is arranged in the intermediate disk 20.

[0033] In the cycloid internal meshing gear pump 4, the outer rotor 18 meshes with the inner rotor 19, and the eccentric cylinder 16 is matched with the outer rotor 18. Specifically, the outer rotor 18 is installed in the eccentric cylinder 16. Figure 3 As shown, a pin 17 is provided on the positioning eccentric cylinder 16, and the eccentric cylinder 16 is installed in the pump housing 12. A first pressing plate 10 and a second pressing plate 11 are provided on both sides of the inner rotor 19, and both the first pressing plate 10 and the second pressing plate 10 are provided with through holes that match the inner shaft. The first pressing plate 10 and the intermediate disk 20 are matched with each other end face to end face.

[0034] In addition, the power line of the three-phase AC motor 1 is led out through the sintered terminal 8 .

[0035] Working principle:

[0036] The first graphite bearing 5 and the second graphite bearing 9 with self-lubricating characteristics are respectively installed at the two ends of the space of the motor housing 15 to support the rotation of the inner shaft 14; the power line of the three-phase AC motor 1 is led out through the sintered terminal 8, and the sintered terminal 8 has a sealing function; the intermediate transmission mechanism between the three-phase AC motor 1 and the cycloid internal gear pump 4 is eliminated, and the integration is achieved by an inner shaft 14, thereby obtaining the interconnection between the pump chamber and the motor chamber, that is, the hydraulic oil can flow between them; the pump housing 12 and the motor housing 15 form a radial sealing structure with high sealing reliability; the pin 17 in the cycloid internal gear pump 4 is used to position the circumferential rotation of the eccentric cylinder 16, the first pressure plate 10 and the second pressure plate 11, and its installation position is determined according to the pump inlet and outlet and the eccentric direction.

[0037] During operation, the inner rotor 19 rotates driven by the inner shaft 14, and the outer rotor 18 meshes and rotates around the inner rotor 19 to produce a change in cavity volume. The oil enters through the inlet port P1 and is discharged from the outlet port P2.

[0038] The coaxial design simplifies the intermediate transmission mechanism, which is of great significance for weight reduction. The motor 1 and the cycloid internal gear pump 4 also get rid of the traditional shaft tail mechanical seal method, achieving double sealing insurance without the risk of oil leakage. There is no physical isolation between the inner cavity of the motor 1 and the cycloid internal gear pump 4. The hydraulic oil in the pump cavity can enter the inner cavity of the motor 1 at any time, and return to the pump cavity and be discharged through the pump, so that the heat generated by the motor 1 is conducted out through the hydraulic oil, which has a cooling effect, thereby avoiding the accumulation of heat energy generated by the motor 1 during operation and affecting the working performance of the motor 1.

[0039] The above embodiments are explanations of the present invention, not limitations of the present invention. Although the present invention is described in conjunction with the preferred embodiments, it should be understood that the present invention is not limited to the preferred embodiments. Those skilled in the art can make various equivalent modifications and substitutions to the technical solutions of the present invention based on the teachings of the present invention. Therefore, the scope of the present invention should be limited by the claims, and all those equivalent modifications and substitutions belong to the protection scope of the technical solutions of the present invention.

Claims

1. A high-speed, low-pressure, sealless electric internal gear pump for aviation, comprising a three-phase AC motor (1), a cycloid internal gear pump (4) matched with the three-phase AC motor, characterized in that The rotating shaft of the three-phase AC motor and the driving shaft of the cycloid internal meshing gear pump are coaxial structures, and the coaxial structure is an inner shaft (14); The inner shaft (14) is a hollow shaft, and the pump cavity and the motor cavity are connected to each other, so that the hydraulic oil in the pump cavity enters the motor cavity and returns to the pump cavity to be discharged through the pump.

2. The high-speed, low-pressure, sealless electric internal gear pump for aviation according to claim 1, characterized in that: A pump housing (12) of a cycloid internal meshing gear pump (4) and a motor housing (15) of a three-phase AC motor (1) form a radial sealing structure.

3. The high-speed, low-pressure, sealless electric internal gear pump for aviation according to claim 1 or 2, characterized in that: The inner shaft (14) is open at the shaft tail end of the cycloid internal meshing gear pump (4) without a sealing structure.

4. The high-speed, low-pressure, sealless electric internal gear pump for aviation according to claim 1, characterized in that: An intermediate disk (20) is provided between the three-phase AC motor (1) and the cycloid internal gear pump (4); the intermediate disk and the motor housing (15) form an internal component space of the three-phase AC motor, and the intermediate disk and the pump housing (12) form an internal component space of the cycloid internal gear pump (4).

5. The high-speed, low-pressure, sealless electric internal gear pump for aviation according to claim 1 or 4, characterized in that: The inner shaft (14) is supported and positioned by a graphite bearing in a three-phase AC motor (1); one end of the inner shaft is connected to an inner rotor (19) in a cycloid internal meshing gear pump (4), meshes with the inner rotor to form an outer rotor (18), and cooperates with the outer rotor to form an eccentric cylinder (16).

6. The high-speed, low-pressure, sealless electric internal gear pump for aviation according to claim 1 or 4, characterized in that: One end of the inner shaft (14) is connected to the inner rotor (19) of the cycloid internal meshing gear pump (4), and a first pressing plate (10) and a second pressing plate (11) are respectively provided on both sides of the inner rotor, and both the first pressing plate and the second pressing plate are provided with through holes that match the inner shaft.

7. The high-speed, low-pressure, sealless electric internal gear pump for aviation use according to claim 4, characterized in that: The matching surfaces of the intermediate disk (20) and the pump housing (12) are provided with a plurality of sealing rings (13).

8. The high-speed, low-pressure, sealless electric internal gear pump for aviation use according to claim 1, 2, 3, 4, or 7, characterized in that: The power line of the three-phase AC motor (1) is led out through the sintered terminal (8).

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