Split type shielding electric gear pump and cooling method thereof

Abstract

The invention provides a split type shielding electric gear pump and a cooling method thereof, and can solve the problems that a motor and a gear pump of an existing integral type shielding electric gear pump cannot be independently assembled, the motor and the gear pump cannot be integrally decomposed, so that the gear pump is inconvenient to independently carry out a running-in test, and the gear pump leaks. The electric gear pump comprises a gear pump body and a motor, the gear pump body comprises a pump shell and a pump shaft, the motor comprises a machine shell, a stator and a rotor, one end of the pump shell is connected with one end of the machine shell through a sealing end face, air gaps are formed among the rotor, the stator and the machine shell, the input end of the pump shaft extends out of the pump shell and extends into the machine shell, and a leakage gap is formed between the input end of the pump shaft and the pump shell. The input end of the pump shaft is coaxially connected with one end of the rotor, the rotor is provided with an axially-through motor backflow channel, the pump shaft is provided with an axially-through gear pump backflow channel, and the space in the pump shell, the leakage gap, the air gap, the motor backflow channel and the gear pump backflow channel form a working medium cooling loop.

Description

Technical Field

[0001] The invention relates to a gear pump, in particular to a split-type shielded electric gear pump and a cooling method thereof. Background Art

[0002] The gear pump is a commonly used hydraulic pump, which is widely used in aerospace, mining equipment, metallurgical equipment, construction machinery, engineering machinery, agricultural and forestry machinery and other fields. In some fields, such as aerospace, in order to shorten the overall dimensions of the gear pump and improve the working reliability of the gear pump, a shielded electric gear pump is usually used. The existing shielded electric gear pump is an integral structure, including a motor and a gear pump, and the motor and the gear pump are coaxially connected. The problems with the shielded electric gear pump are: 1. The gear pump needs to be assembled after the motor is assembled, and the motor and the gear pump cannot be assembled separately; 2. The motor and the gear pump cannot be disassembled as a whole, which makes it inconvenient to carry out a running-in test on the gear pump separately; 3. The gear pump leaks. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problems of the existing integral shielded electric gear pump, that is, the motor and the gear pump cannot be assembled separately, the motor and the gear pump cannot be disassembled as a whole, which makes it inconvenient to carry out a running-in test on the gear pump separately, and the gear pump leaks, and to provide a split shielded electric gear pump and a cooling method thereof.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A split shielded electric gear pump comprises a gear pump and a motor; the gear pump comprises a pump housing and a pump shaft; the motor comprises a housing, a stator arranged in the housing, and a rotor installed in the stator; one end of the pump housing is connected to one end of the housing; the special feature is that:

[0006] The pump casing and the casing are connected by sealed end face connection;

[0007] An air gap is provided between the rotor, the stator and the casing;

[0008] The input end of the pump shaft extends out of the pump housing and into the machine housing; a leakage gap is provided between the input end of the pump shaft and the pump housing; the input end of the pump shaft is coaxially connected to one end of the rotor;

[0009] The rotor is provided with an axially penetrating motor return channel; the pump shaft is provided with an axially penetrating gear pump return channel;

[0010] The inner space of the pump housing, the leakage gap, the air gap, the motor return channel and the gear pump return channel constitute a working medium cooling circuit.

[0011] Furthermore, a spiral groove or a spiral ridge is provided on an outer wall at one end of the rotor.

[0012] Furthermore, the spiral rotation direction of the spiral groove or the spiral ridge is the same as the rotation direction of the rotor, which is used to increase the leakage rate of the working medium at the leakage gap; or, the spiral rotation direction of the spiral groove or the spiral ridge is opposite to the rotation direction of the rotor, which is used to reduce the leakage rate of the working medium at the leakage gap.

[0013] Furthermore, the input end of the pump shaft comprises a first cylindrical section, a second cylindrical section, a third cylindrical section and a fourth cylindrical section which are coaxially arranged in sequence in a direction away from the rotor;

[0014] The diameter of the first cylindrical segment is the same as the diameter of the third cylindrical segment and is smaller than the diameter of the second cylindrical segment, and the diameter of the second cylindrical segment is smaller than the diameter of the fourth cylindrical segment;

[0015] The first cylindrical section and the second cylindrical section extend out of the pump casing and into the machine casing;

[0016] A leakage gap is provided between the third cylindrical section, the fourth cylindrical section and the pump casing;

[0017] One end of the rotor is provided with a secondary step hole adapted to the first cylindrical section and the second cylindrical section; the secondary step hole is connected to the motor return channel; the first cylindrical section and the second cylindrical section are sealingly sleeved in the secondary step hole.

[0018] Furthermore, the first cylindrical section and the second cylindrical section are all spline-fitted or key-fitted with the secondary step hole;

[0019] At least one sealing ring is used for sealing connection between the first cylindrical section and the corresponding position of the secondary step hole.

[0020] Furthermore, the compression amount of the sealing ring is 10% to 15%, and there are two sealing rings.

[0021] Furthermore, the pump casing is sealed and connected to the machine casing via a flange.

[0022] At the same time, the present invention also provides a cooling method for the above-mentioned split-type shielded electric gear pump, which is special in that it includes the following steps:

[0023] Step 1: The motor is powered on, the rotor drives the pump shaft to rotate, the gear pump starts to work, and a pressurized working medium is formed in the high-pressure chamber in the pump housing;

[0024] Step 2: The pressurized working medium enters the air gap between the stator, rotor and casing from the leakage gap, enters the motor return channel and the gear pump return channel from the other end of the rotor, and then returns to the low-pressure cavity in the pump casing, thereby cooling the stator and rotor of the motor.

[0025] Furthermore, step 2 is specifically as follows:

[0026] Through the preset spiral groove or spiral ridge spiral rotation direction, the leakage rate of the working medium at the leakage gap is increased or reduced, and then enters the air gap between the stator and the rotor and the casing, enters the motor return channel and the gear pump return channel from the other end of the rotor, and then returns to the low-pressure chamber in the pump casing, thereby realizing the cooling of the stator and rotor of the motor.

[0027] Beneficial effects of the present invention:

[0028] 1. The present invention provides a split shielded electric gear pump, which has a small axial dimension. Since the motor and the gear pump are split structures, the motor and the gear pump are easy to disassemble and assemble, and the motor and the gear pump can be assembled separately and run-in test verification can be carried out. In addition, since the connection between the pump casing and the casing adopts a sealed end face connection, there will be no leakage problem.

[0029] 2. The present invention is provided with a spiral groove or a spiral ridge, and the spiral rotation direction of the spiral groove or the spiral ridge is determined according to different working conditions, which can achieve the effect of supercharging and reverse supercharging, thereby increasing or reducing the leakage speed in the leakage gap. When the spiral rotation direction of the spiral groove or the spiral ridge is the same as the direction of rotation of the rotor, even if the outlet pressure of the gear pump is relatively low and cannot overcome the flow resistance of the cooling circuit, the pressure requirement for overcoming the flow resistance of the cooling circuit can be met by the supercharging effect of the spiral groove or the spiral ridge.

[0030] 3. In the present invention, at least one sealing ring is used for sealing sleeve connection between the first cylindrical section and the corresponding position of the secondary step hole, which can prevent the working medium in the gear pump from flowing back to the low-pressure chamber in the pump housing through this point, and cannot achieve cooling of the motor stator and rotor. In addition, in order to prevent over-positioning, the compression amount of the sealing ring is 10% to 15%, and there are two sealing rings.

[0031] 4. The present invention provides a cooling method for a split-type shielded electric gear pump. The method is simple and reliable, has good cooling effect, and is suitable for different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of an embodiment of a split-type shielded electric gear pump of the present invention;

[0033] Figure 2 yes Figure 1 A partial enlarged view of .

[0034] Description of reference numerals:

[0035] 1-gear pump, 11-bearing, 12-cover plate, 13-driven gear unit, 14-pump shaft, 15-pump housing, 2-motor, 20-housing, 21-stator, 22-rotor, 3-motor return channel, 4-gear pump return channel, 5-spiral groove. DETAILED DESCRIPTION

[0036] like Figure 1-Figure 2As shown, a split shielded electric gear pump includes a gear pump 1 and a motor 2. The gear pump 1 includes a pump housing 15, a pump shaft 14 and a cover plate 12. The motor 2 includes a housing 20, a stator 21 disposed in the housing 20, and a rotor 22 installed in the stator 21. An air gap is provided between the rotor 22, the stator 21 and the housing 20. One end of the pump housing 15 is connected to one end of the housing 20, and the pump housing 15 and the housing 20 are connected by a flange seal. The other end of the pump housing 15 is connected to the cover plate 12 by bolts. The cover plate 12 and the pump housing 15 constitute a gear pump chamber. Two radially arranged groups of bearing units are arranged in the gear pump chamber. Each group of bearing units includes two oppositely arranged bearings 11. A driven gear unit 13 is arranged between the two bearings 11 of one group of bearing units. The input end of the pump shaft 14 includes a first cylindrical section, a second cylindrical section, a third cylindrical section and a fourth cylindrical section which are coaxially arranged in sequence in a direction away from the rotor 22. The diameter of the first cylindrical section is the same as the diameter of the third cylindrical section and is smaller than the diameter of the second cylindrical section. The diameter of the second cylindrical section is smaller than the diameter of the fourth cylindrical section. The first cylindrical section and the second cylindrical section extend out of the pump housing 15 and extend into the housing 20. A leakage gap is provided between the third cylindrical section and the fourth cylindrical section and the pump housing 15. The output end of the pump shaft 14 is provided between two bearings 11 of another group of bearing units. A driving gear located between the end faces of the two bearings 11 is provided on the outer wall of the output end of the pump shaft 14. The driving gear is meshed with the driven gear of the driven gear unit 13. The disengagement side of the driving gear and the driven gear of the driven gear unit 13 forms a low-pressure chamber, and the closing side of the driving gear and the driven gear of the driven gear unit 13 forms a high-pressure chamber. The driving gear and the pump shaft 14 in this embodiment are an integrated structure. One end of the rotor 22 is provided with a secondary step hole adapted to the first cylindrical section and the second cylindrical section. The first cylindrical section and the second cylindrical section are sealingly sleeved in the secondary step hole, and the first cylindrical section and the second cylindrical section are splined or keyed with the secondary step hole (splined in this embodiment). In order to prevent over-positioning, two sealing rings are used for sealing sleeve connection between the corresponding positions of the first cylindrical section and the secondary step hole. The compression amount of the two sealing rings is 10% to 15%. The sealing ring close to the pump housing 15 is the main seal, and the sealing ring away from the pump housing 15 is the auxiliary seal. A small amount of working medium is allowed to leak through the spline fit between the first cylindrical section and the secondary step hole.A spiral groove 5 is provided on the outer wall of one end of the rotor 22, and the spiral rotation direction of the spiral groove is determined according to different working conditions. When the spiral rotation direction of the spiral groove 5 is the same as the direction of rotation of the rotor 22, a boosting effect can be achieved, thereby increasing the leakage rate of the working medium at the leakage gap. When the spiral rotation direction of the spiral groove 5 is opposite to the direction of rotation of the rotor 22, a reverse boosting effect can be achieved, thereby reducing the leakage rate of the working medium at the leakage gap (in other embodiments, a spiral ridge is provided on the outer wall of one end of the rotor 22, and the spiral rotation direction of the spiral ridge is determined according to different working conditions. When the spiral rotation direction of the spiral ridge is the same as the direction of rotation of the rotor 22, a boosting effect can be achieved, thereby increasing the leakage rate of the working medium at the leakage gap. When the spiral rotation direction of the spiral ridge is opposite to the direction of rotation of the rotor 22, a reverse boosting effect can be achieved, thereby reducing the leakage rate of the working medium at the leakage gap). The rotor 22 is provided with an axially penetrating motor return channel 3, which is connected to the secondary step hole, and the pump shaft 14 is provided with an axially penetrating gear pump return channel 4. The inner space of the pump housing 15, the leakage gap, the air gap, the motor return channel 3 and the gear pump return channel 4 constitute a working medium cooling circuit. In this embodiment, the motor 2 is a shielded motor (in other embodiments, a non-shielded motor that allows the working medium to enter the inner cavity can be used), and the bearing 11 is a sliding bearing (in other embodiments, a needle bearing can be used).

[0037] The cooling method of this embodiment comprises the following steps:

[0038] Step 1: The motor 2 is powered on, the rotor 22 drives the pump shaft 14 to rotate, the gear pump 1 starts to work, and a pressurized working medium is formed in the high-pressure chamber in the pump housing 15;

[0039] Step 2: By means of the preset spiral rotation direction of the spiral groove 5, the leakage rate of the working medium at the leakage gap is increased or decreased, and then the working medium enters the air gap between the stator 21 and the rotor 22 and the casing 20, enters the motor return channel 3 and the gear pump return channel 4 from the other end of the rotor 22, and then returns to the low-pressure chamber in the pump casing 15, thereby realizing the cooling of the stator 21 and the rotor 22 of the motor 2.

[0040] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A split-type shielded electric gear pump, comprising a gear pump (1) and a motor (2); the gear pump (1) comprises a pump housing (15) and a pump shaft (14); the motor (2) comprises a housing (20), a stator (21) disposed in the housing (20), and a rotor (22) installed in the stator (21); one end of the pump housing (15) is connected to one end of the housing (20); Features: The pump housing (15) and the machine housing (20) are connected by sealed end surface connection; An air gap is provided between the rotor (22), the stator (21) and the casing (20); The input end of the pump shaft (14) extends out of the pump housing (15) and into the machine housing (20); a leakage gap is provided between the input end of the pump shaft (14) and the pump housing (15); the input end of the pump shaft (14) is coaxially connected to one end of the rotor (22); The rotor (22) is provided with an axially penetrating motor return channel (3); the pump shaft (14) is provided with an axially penetrating gear pump return channel (4); The inner space of the pump housing (15), the leakage gap, the air gap, the motor return channel (3) and the gear pump return channel (4) form a working medium cooling circuit.

2. The split-type shielded electric gear pump according to claim 1 is characterized in that: A spiral groove (5) or a spiral ridge is provided on the outer wall of one end of the rotor (22).

3. The split-type shielded electric gear pump according to claim 2 is characterized in that: The spiral rotation direction of the spiral groove (5) or the spiral ridge is the same as the rotation direction of the rotor (22), which is used to increase the leakage speed of the working medium at the leakage gap; or the spiral rotation direction of the spiral groove (5) or the spiral ridge is opposite to the rotation direction of the rotor (22), which is used to reduce the leakage speed of the working medium at the leakage gap.

4. The split-type shielded electric gear pump according to any one of claims 1 to 3, characterized in that: The input end of the pump shaft (14) comprises a first cylindrical section, a second cylindrical section, a third cylindrical section and a fourth cylindrical section which are coaxially arranged in sequence in a direction away from the rotor (22); The diameter of the first cylindrical segment is the same as the diameter of the third cylindrical segment and is smaller than the diameter of the second cylindrical segment, and the diameter of the second cylindrical segment is smaller than the diameter of the fourth cylindrical segment; The first cylindrical section and the second cylindrical section extend out of the pump casing (15) and into the machine casing (20); A leakage gap is provided between the third cylindrical section, the fourth cylindrical section and the pump housing (15); One end of the rotor (22) is provided with a secondary step hole adapted to the first cylindrical section and the second cylindrical section; the secondary step hole is connected to the motor return channel (3); the first cylindrical section and the second cylindrical section are sealingly sleeved in the secondary step hole.

5. The split-type shielded electric gear pump according to claim 4 is characterized in that: The first cylindrical section and the second cylindrical section are both spline-fitted or key-fitted with the secondary step hole; At least one sealing ring is used for sealing connection between the first cylindrical section and the corresponding position of the secondary step hole.

6. The split-type shielded electric gear pump according to claim 5 is characterized in that: The compression amount of the sealing ring is 10% to 15%, and there are two sealing rings.

7. The split-type shielded electric gear pump according to claim 1 is characterized in that: The pump casing (15) is sealed and connected to the machine casing (20) via a flange.

8. A cooling method for a split-type canned electric gear pump according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: The motor (2) is powered on, the rotor (22) drives the pump shaft (14) to rotate, and the gear pump (1) starts to work, forming a pressurized working medium in the high-pressure chamber in the pump housing (15); Step 2: The pressurized working medium enters the air gap between the stator (21) and the rotor (22) and the housing (20) from the leakage gap, enters the motor return channel (3) and the gear pump return channel (4) from the other end of the rotor (22), and then returns to the low-pressure chamber in the pump housing (15), thereby achieving cooling of the stator (21) and the rotor (22) of the motor (2).

9. The cooling method of the split-type canned electric gear pump according to claim 8, characterized in that: Step 2 is as follows: The spiral direction of the preset spiral groove (5) or spiral ridge increases or decreases the leakage speed of the working medium at the leakage gap, and then enters the air gap between the stator (21) and the rotor (22) and the housing (20), enters the motor return channel (3) and the gear pump return channel (4) from the other end of the rotor (22), and then returns to the low-pressure chamber in the pump housing (15), thereby achieving cooling of the stator (21) and the rotor (22) of the motor (2).

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