Motor direct drive pump

Abstract

The utility model discloses a motor direct drive pump, and relates to the technical field of drive pumps, a stator assembly, a rotor assembly, a main shaft assembly and a piston assembly are installed in a shell assembly, the stator assembly is fixed on the shell assembly, a rotor magnet is installed on a connecting disc of the rotor assembly in a positioning mode, and the rotor magnet is arranged on the periphery of the stator assembly in a surrounding mode. The main shaft assembly is rotationally assembled in an inner cavity of the shell assembly, circumferentially fixed to the connecting disc and used for achieving driving rotation, and due to the fact that the rotor assembly has the larger radial size, larger torque can be provided; the main shaft assembly is provided with an eccentric driving part, the piston assembly is slidably assembled in the piston cavity, and when the main shaft assembly rotates, the eccentric driving part drives the piston assembly to do reciprocating linear translation, so that pumping is achieved; a motor structure and a pump structure are integrated with each other, so that the structure of the pump body is simplified, higher integrity is achieved, the rotor assembly has larger radial size, and the size of the whole machine can be reduced under the condition that the same torque is output.

Description

Technical Field

[0001] This utility model relates to the field of drive pump technology, and more specifically to a direct-drive pump for electric motors. Background Technology

[0002] Agricultural sprayers typically use an electric motor to drive a piston (the power element of the pump in the sprayer) to reciprocate. Existing drive devices generally use an asynchronous motor to drive the piston, and such drive devices require a speed reducer to be installed between the asynchronous motor and the pump.

[0003] In traditional drive devices, the asynchronous motor is connected to the piston through a gearbox, resulting in low overall efficiency, around 70%, with the remaining energy being dissipated as heat. Furthermore, the device has a short lifespan, typically around 200 hours.

[0004] Due to the structural design of the piston, gearbox, stator, and rotor, the chamber where the piston is located and the chambers where the stator and rotor are located are structurally isolated from each other. When the drive unit malfunctions, it is necessary to disassemble both chambers for repair, which is a complicated operation.

[0005] For those skilled in the art, simplifying the structure of the pump body is a technical problem that needs to be solved. Utility Model Content

[0006] The core of this utility model lies in providing a direct-drive pump that integrates the pump and the drive motor into one unit for direct drive, thus simplifying the structure. The rotor assembly is located on the outer periphery of the stator assembly, which can reduce the overall size of the machine and further simplify the structure. The specific solution is as follows:

[0007] A direct-drive pump for electric motors, comprising:

[0008] A housing assembly having a piston chamber;

[0009] Stator assembly, fixed to the inner cavity of the housing assembly;

[0010] The rotor assembly includes a connecting disk and a rotor magnet, the connecting disk being used to position and support the rotor magnet, such that the rotor magnet is disposed around the outer periphery of the stator assembly;

[0011] A spindle assembly includes a spindle, which is rotatably mounted in the inner cavity of the housing assembly and circumferentially fixed to the connecting disc; the spindle is provided with an eccentric drive unit.

[0012] The piston assembly is slidably mounted in the piston chamber and is driven by the eccentric drive unit to perform reciprocating linear translation.

[0013] Optionally, the housing assembly is provided with a shaft sleeve, and the main shaft is rotatably mounted in the inner cavity of the shaft sleeve;

[0014] The stator assembly is fixedly assembled to the outer periphery of the shaft cylinder.

[0015] Optionally, a cap is provided at the end of the shaft cylinder, a first bearing is provided between the main shaft and the cap, and a second bearing and an oil seal are provided between the main shaft and the shaft cylinder, with the oil seal located between the first bearing and the second bearing in the axial direction.

[0016] Optionally, the housing assembly includes a pump housing and a machine housing that are spliced ​​and fixed together, and the piston chamber and the shaft cylinder are disposed in the pump housing;

[0017] The stator assembly and the rotor assembly are disposed in the cavity formed by the housing and the pump housing.

[0018] Optionally, one end of the spindle is fixed to the connecting disk, and the other end is provided with the eccentric drive unit for driving the piston assembly to perform reciprocating linear translation.

[0019] Optionally, the sidewall of the piston assembly is cylindrical, and the piston assembly is provided with a notch;

[0020] The eccentric drive unit provided at the end of the main shaft is used to insert into the notch and to drive the piston assembly to translate.

[0021] Alternatively, the piston assembly includes a piston head and a piston connecting rod, with one end of the piston connecting rod hinged to the eccentric drive unit and the other end hinged to the piston head.

[0022] Optionally, the main shaft is provided with an eccentric counterweight, the center of gravity of which is symmetrical with respect to the center of gravity of the eccentric drive unit about the axis of the main shaft.

[0023] Optionally, the housing assembly is provided with two piston chambers, and the piston assembly operates alternately in the two piston chambers.

[0024] Optionally, a third bearing is mounted on the eccentric drive unit.

[0025] Optionally, the connecting plate includes a central portion, a connecting portion, and a surrounding portion, wherein the connecting portion extends radially and its two ends are respectively fixed to the central portion and the surrounding portion;

[0026] The connecting portions are radially distributed around the central portion.

[0027] This invention provides a direct-drive pump for a motor. A stator assembly, a rotor assembly, a main shaft assembly, and a piston assembly are installed within a housing assembly. The stator assembly is fixed to the housing assembly. A rotor magnet is positioned and installed on a connecting plate of the rotor assembly, causing the rotor magnet to surround the outer periphery of the stator assembly. The main shaft assembly is rotatably assembled into the inner cavity of the housing assembly and circumferentially fixed to the connecting plate for driving rotation. Due to the larger radial dimension of the rotor assembly, it can provide greater torque. The main shaft assembly is provided with an eccentric drive unit, and the piston assembly is slidably assembled in the piston cavity. When the main shaft assembly rotates, the eccentric drive unit drives the piston assembly to perform reciprocating linear translation, thereby achieving pumping. This invention integrates the motor structure and the pump structure, thereby simplifying the pump body structure and achieving higher integration. Moreover, the larger radial dimension of the rotor assembly allows for a smaller overall size of the pump while maintaining the same output torque. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1A This is a first-view isometric view of a specific embodiment of the direct-drive pump of this utility model;

[0030] Figure 1B This is a second-view isometric view of a specific embodiment of the direct-drive pump of this utility model;

[0031] Figure 1C This is a cross-sectional view of a specific embodiment of the direct-drive pump of this utility model;

[0032] Figure 2 Axonometric drawing with the casing removed;

[0033] Figure 3A A first-view isometric view of a specific embodiment of the housing assembly;

[0034] Figure 3B A second-view isometric view of a specific embodiment of the housing assembly;

[0035] Figure 3C A cross-sectional view of one specific embodiment of the housing assembly;

[0036] Figure 4A A first-view isometric view of the stator assembly, rotor assembly, spindle assembly, and piston assembly in action;

[0037] Figure 4BA second-view isometric view of the stator assembly, rotor assembly, spindle assembly, and piston assembly in conjunction with each other;

[0038] Figure 5A A first-view isometric view of the stator and rotor assemblies in operation;

[0039] Figure 5B A second-view isometric view of the stator and rotor assemblies in conjunction.

[0040] Figure 6A A first-view isometric view of the rotor assembly;

[0041] Figure 6B A second-view isometric view of the rotor assembly;

[0042] Figure 7 This is an isometric view of the stator assembly.

[0043] Figure 8A An isometric view of the mating of the spindle assembly and piston assembly;

[0044] Figure 8B This is a cross-sectional view showing the assembly of the spindle and piston components.

[0045] The image includes:

[0046] 10 housing assembly; 101 piston chamber; 102 shaft cylinder; 1021 fixing screw hole; 103 cylinder cover; 1031 fixing screw; 110 pump housing; 120 machine housing;

[0047] Stator assembly 20;

[0048] Rotor assembly 30; connecting disk 301; center part 3011; connecting part 3012; surrounding part 3013; rotor magnet 302;

[0049] Spindle assembly 40; spindle 401; eccentric drive unit 4011; eccentric counterweight 4012; first bearing 402; second bearing 403; third bearing 404; oil seal 405;

[0050] Piston assembly 50; notch 501. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solution of this utility model, the direct-drive pump of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] The direct-drive pump of this utility model includes a housing assembly 10, a stator assembly 20, a rotor assembly 30, a main shaft assembly 40, a piston assembly 50, and other structures. The housing assembly 10 is the outer shell structure of the entire direct-drive pump, and the other components are installed inside the housing assembly 10. Figure 3A, Figure 3B , Figure 3C As shown, a cavity for the corresponding structure is provided inside the housing assembly 10, and the cavity provides limiting support for each structure installed on it.

[0053] Combination Figure 1A , Figure 1B , Figure 1C As shown, the housing assembly 10 is provided with a piston chamber 101, which is a cavity structure. At least a part of the structure of the piston assembly 50 is located between the piston chambers 101. When the piston assembly 50 reciprocates relative to the piston chamber 101, it changes the size of the piston chamber 101 and periodically realizes the pumping process.

[0054] The piston chamber 101 is connected to the air inlet and the air outlet. One-way valves are respectively provided at the air inlet and the air outlet. When the space inside the piston chamber 101 increases, gas or liquid is drawn in from the outside through the air inlet. When the space inside the piston chamber 101 decreases, gas or liquid is pumped out through the air outlet.

[0055] At least one piston chamber 101 is provided on the housing assembly 10, but two or more piston chambers 101 may also be provided. Each piston chamber 101 is fitted with a piston assembly 50, and the piston assembly 50 can periodically change the spatial size of each piston chamber 101.

[0056] The stator assembly 20 is fixed to the inner cavity of the outer casing assembly 10. The stator assembly 20 and the outer casing assembly 10 are circumferentially fixed, and there is no relative rotation between them. The stator assembly 20 remains in a fixed state. The stator assembly 20 is provided with a stator core and a stator coil, with the stator coil wound on the stator core; combined with Figure 7 As shown, the structure of the stator core is displayed, but the stator coils are not shown.

[0057] Combination Figure 6A , Figure 6B As shown, the rotor assembly 30 includes a connecting disk 301 and a rotor magnet 302. The center of the connecting disk 301 is circumferentially fixed to the main shaft assembly 40, and the main shaft assembly 40 and the rotor assembly 30 rotate synchronously. The connecting disk 301 is used to position and support the rotor magnet 302, as shown. Figure 6B As shown, the connecting disk 301 has a cylindrical shell structure, and a ring of rotor magnets 302 is fixedly arranged on the inner wall of the cylinder. Figure 5A , Figure 5B As shown, the cylindrical structure of the connecting disc 301 is coaxially mounted on the outer periphery of the stator assembly 20, so that the rotor magnet 302 is arranged around the outer periphery of the stator assembly 20. When the stator coil of the stator assembly 20 is energized, it generates a magnetic field, which generates a magnetic force with the rotor magnet 302 to drive the rotor assembly 30 to rotate.

[0058] The spindle assembly 40 includes a spindle 401, which is rotatably mounted in the inner cavity of the housing assembly 10. The spindle 401 is circumferentially fixed to the connecting disk 301. The spindle 401 and the connecting disk 301 can be connected by a flat key or spline. The spindle 401 and the rotor assembly 30 rotate synchronously. With the rotor assembly 30 and the stator assembly 20 acting in relation to each other, the rotor assembly 30 is the active rotating structure, and the spindle 401 is the passive rotating structure.

[0059] The spindle 401 is provided with an eccentric drive unit 4011, which is combined with Figure 8A , Figure 8B As shown, the central axis of the eccentric drive unit 4011 is offset from the central axis of the entire spindle, and the eccentric drive unit 4011 rotates around the axis of the entire spindle 401. Figure 8B As shown, the axis of the main shaft 401 is C1, the axis of the eccentric drive unit 4011 is C2, and the offset distance between the two axes C1 and C2 is O1.

[0060] The piston assembly 50 is slidably mounted on the piston cavity 101 and is driven by the eccentric drive unit 4011 to perform reciprocating linear translation. When the eccentric drive unit 4011 rotates in a circle, it can drive the piston assembly 50 to reciprocate along the piston cavity 101. During the reciprocating translation of the piston assembly 50, the space of the piston cavity 101 is periodically increased and decreased, thereby realizing gas or liquid pumping.

[0061] This invention's direct-drive pump integrates the motor and pump structures, eliminating the need for a connecting structure and simplifying the overall design for greater integration. The rotor assembly 30 has a larger radial dimension, enclosing the stator assembly 20. The radial dimension of the stator assembly 20 is smaller than that of the rotor assembly 30. This larger radial dimension of the rotor assembly 30 allows for a larger lever arm, enabling a smaller overall size while maintaining the same output torque.

[0062] Based on the above scheme, the outer shell assembly 10 of this utility model is provided with a shaft cylinder 102. The inner cavity of the shaft cylinder 102 is cylindrical, and the entire shaft cylinder 102 is a hollow cylindrical structure that runs through the axial direction. The shaft cylinder 102 divides the inner cavity of the outer shell assembly 10 into two chambers. The larger chamber outside the shaft cylinder 102 is used to install the stator assembly 20; the main shaft 401 is rotatably mounted in the smaller chamber inside the shaft cylinder 102, and the main shaft 401 rotates within the inner cavity of the shaft cylinder 102. The stator assembly 20 is fixedly mounted on the outer periphery of the shaft cylinder 102, and the stator core of the stator assembly 20 is sleeved outside the shaft cylinder 102, supported and positioned by the shaft cylinder 102. The shaft cylinder 102 isolates the main shaft 401 and the stator assembly 20 from each other.

[0063] A sleeve cap 103 is provided at the end of the shaft sleeve 102, combined with... Figure 3AAs shown, a fixing screw hole 1021 is provided on the end face of the shaft cylinder 102, such as... Figure 2 As shown, the cylinder cover 103 is screwed onto the fixing screw hole 1021 by fixing screws 1031, thereby fixing the cylinder cover 103. The cylinder cover 103 can be axially pressed onto the shaft cylinder 102 and restrict the position of the stator assembly 20. Figure 1C As shown, a stepped structure is provided on the cylinder cover 103, which presses against the end face and side wall of the stator assembly 20 respectively, thereby axially limiting the stator assembly 20 and radially limiting the stator assembly 20.

[0064] Combination Figure 1C As shown, a first bearing 402 is disposed between the main shaft 401 and the cylinder cover 103. The outer ring of the first bearing 402 is fixed to the inner cavity of the cylinder cover 103, and the inner ring is fixed to the main shaft 401. A second bearing 403 and an oil seal 405 are disposed between the main shaft 401 and the cylinder 102. The outer ring of the second bearing 403 is fixed to the inner cavity of the cylinder 102, and the inner ring is fixed to the main shaft 401. The first bearing 402 and the second bearing 403 provide support for the main shaft 401, allowing the main shaft 401 to rotate smoothly relative to the cylinder 102. The inner ring of the oil seal 405 is fitted onto the outer surface of the main shaft 401, and the outer ring contacts the cylinder 102. The oil seal 405 is located between the first bearing 402 and the second bearing 403 in the axial direction. The oil seal 405 can be a rubber gasket, used to prevent liquid in the pump from flowing into the stator assembly 20 and rotor assembly 30 areas of the motor.

[0065] like Figure 1A , Figure 1B , Figure 1C As shown, the outer casing assembly 10 of this utility model includes a pump casing 110 and a machine casing 120 that are spliced ​​and fixed together. The pump casing 110 and the machine casing 120 are relatively fixed and enclosed to form an internally hollow space. The stator assembly 20 and the rotor assembly 30 are arranged in the cavity formed by the machine casing 120 and the pump casing 110. The piston chamber 101 and the shaft cylinder 102 are arranged on the pump casing 110. The pump casing 110 is used to support and assemble other related structures, while the machine casing 120 mainly serves to provide shelter.

[0066] One end of the pump casing 110 is equipped with a shaft sleeve 102, which divides the space enclosed by the pump casing 110 and the housing 120 into two chambers, which can be referred to as the first chamber and the second chamber. The pump casing 110 and the housing 120 cooperate to close the second chamber. The second chamber is larger and is used to house the stator assembly 20 and the rotor assembly 30. The second chamber is progressive from the first chamber. The first chamber is the space for the main shaft assembly 40. Therefore, when there is a fault in the drive device, the housing 120 can be removed, and the motor part and the pump part can be inspected in sequence, which is convenient for maintenance.

[0067] One end of the main spindle 401 is fixed to the connecting plate 301, and the other end is equipped with an eccentric drive unit 4011 for driving the piston assembly 50 to perform reciprocating linear translation. Figure 1C As shown, the left end of the spindle 401 is provided with an eccentric drive unit 4011, and the right end is fixed to the center part of the connecting disk 301.

[0068] Combination Figure 4A , Figure 4B As shown, the outer periphery of the piston assembly 50 is cylindrical, which can be either a cylindrical or prismatic surface. A blind hole can be provided at the end of the piston assembly 50 to reduce weight and accommodate the pumped gas or liquid. A notch 501 is provided on the side wall of the piston assembly 50. An eccentric drive part 4011 at the end of the main shaft 401 is inserted into the notch 501 to drive the piston assembly 50 to translate. The vertical height of the notch 501 is slightly greater than the outer diameter of the eccentric drive part 4011, and the height of the notch 501 remains equal at all positions. When the eccentric drive part 4011 performs a circular motion, it slides laterally relative to the notch 501, driving the piston assembly 50 to translate axially along its axis. The direction of translation of the piston assembly 50 is perpendicular to the axis of the main shaft 401. The piston assembly 50 is a cylindrical structure, facilitating miniaturization.

[0069] In addition to adopting a straight rod structure, the piston assembly 50 can also adopt a piston structure. The piston assembly 50 includes a piston head and a piston connecting rod (not shown in the figure). One end of the piston connecting rod is hinged to the eccentric drive unit 4011 and the other end is hinged to the piston head. The eccentric drive unit 4011 drives one end of the piston connecting rod to perform a circular motion, and the piston head causes the other end of the piston connecting rod to perform a linear motion. The piston head can reciprocate within the piston cavity 101.

[0070] It should be noted that when the piston assembly 50 adopts a structure combining a piston head and a piston connecting rod, the eccentric drive unit 4011 may not be provided at the end of the main shaft 401, but may be provided in the non-end area of ​​the main shaft 401.

[0071] Two piston chambers 101 are provided on the housing assembly 10, and a piston assembly 50 is provided in each piston chamber. The piston assembly 50 works alternately in the two piston chambers 101. Figure 1C As shown, the piston assembly 50 is a cylindrical body with its two ends extending into two piston chambers 101 respectively. The two ends of the piston assembly 50 move synchronously. When the piston assembly 50 moves downward, the space of the upper piston chamber 101 increases and the space of the lower piston chamber 101 decreases. When the piston assembly 50 moves upward, the space of the upper piston chamber 101 decreases and the space of the lower piston chamber 101 increases.

[0072] When the piston assembly 50 has a cylindrical structure, one or two piston chambers 101 can be provided on the outer shell assembly 10, and the two piston chambers 101 need to be collinear. When the piston assembly 50 adopts a piston head and piston connecting rod combination structure, more than one, two, three or more piston chambers 101 can be provided, and the piston chambers 101 are radially distributed.

[0073] The eccentric drive unit 4011 causes eccentric vibration when the spindle 401 rotates. In order to reduce the vibration of the spindle 401, an eccentric counterweight 4012 is provided on the spindle 401. The center of gravity of the eccentric counterweight 4012 is symmetrical with the center of gravity of the eccentric drive unit 4011 about the axis of the spindle 401, thereby ensuring that the center of gravity of the spindle 401 is on the axis of the spindle 401, and the spindle 401 can rotate more smoothly.

[0074] Combination Figure 1C As shown, a third bearing 404 is mounted on the eccentric drive unit 4011. The inner ring of the third bearing 404 is fixed to the eccentric drive unit 4011, and the outer ring is inserted into the insertion notch 501 of the piston assembly 50 to avoid direct contact between the insertion notch 501 and the eccentric drive unit 4011, which would cause wear.

[0075] Combination Figure 6A , Figure 6B As shown, the connecting disc 301 includes a central portion 3011, a connecting portion 3012, and a surrounding portion 3013. The central portion 3011 is fixedly connected to the main shaft 401, and the connecting portions 3012 are radially distributed around the central portion 3011. The connecting portions 3012 extend radially along the main shaft 401, and their two ends are fixed to the central portion 3011 and the surrounding portion 3013, respectively. A rotor magnet 302 is fixedly installed in the inner cavity of the surrounding portion 3013, which generates torque when energized. The connecting portions 3012 transmit the torque of the surrounding portion 3013 to the central portion 3011, driving the main shaft 401 to rotate. There are gaps between the connecting portions 3012, which can reduce weight.

[0076] This utility model's direct-drive pump integrates the motor and pump into a single design and adopts an external rotor direct-drive method, effectively reducing the product's length along the main shaft axis. When installed on a sprayer, it is more convenient for users to carry.

[0077] The spindle assembly 40 is placed in the first chamber formed by the shaft cylinder 102, and the piston notch 501 is located in the first chamber, so that the drive units of the motor are located in the second chamber and the first chamber. During maintenance, maintenance can be carried out sequentially from the second chamber to the first chamber.

[0078] Direct motor drive results in higher mechanical transmission efficiency, reaching 90%, and a longer service life.

[0079] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electric motor direct drive pump characterized by, The application relates to a piston pump, which comprises the following components: a housing assembly (10) provided with a piston cavity (101); a stator assembly (20) fixed in the inner cavity of the housing assembly (10); a rotor assembly (30) comprising a connecting disc (301) and rotor magnets (302), wherein the connecting disc (301) is used for positioning and supporting the rotor magnets (302), and the rotor magnets (302) are arranged around the outer periphery of the stator assembly (20); a main shaft assembly (40) comprising a main shaft (401), wherein the main shaft (401) is rotatably arranged in the inner cavity of the housing assembly (10) and is fixed to the connecting disc (301) in the circumferential direction, and the main shaft (401) is provided with an eccentric driving part (4011); a piston assembly (50) slidably arranged in the piston cavity (101) and driven by the eccentric driving part (4011) to perform reciprocating linear translation.

2. The motor direct drive pump of claim 1, wherein, The housing assembly (10) is provided with a shaft cylinder (102), and the main shaft (401) is rotatably arranged in the inner cavity of the shaft cylinder (102); The stator assembly (20) is fixedly arranged on the outer periphery of the shaft cylinder (102).

3. The motor direct drive pump of claim 2, wherein, The end of the shaft cylinder (102) is provided with a cylinder cover (103), the first bearing (402) is arranged between the main shaft (401) and the cylinder cover (103), the second bearing (403) and an oil seal (405) are arranged between the main shaft (401) and the shaft cylinder (102), and the oil seal (405) is located between the first bearing (402) and the second bearing (403) in the axial direction.

4. The motor direct drive pump of claim 2, wherein, The housing assembly (10) comprises a pump shell (110) and a machine shell (120) which are fixedly connected to each other, and the piston cavity (101) and the shaft cylinder (102) are arranged in the pump shell (110); The stator assembly (20) and the rotor assembly (30) are arranged in the cavity formed by the pump shell (110) and the machine shell (120).

5. The motor direct drive pump of claim 2, wherein, One end of the main shaft (401) is fixed to the connecting disc (301), and the other end is provided with the eccentric driving part (4011) for driving the piston assembly (50) to perform reciprocating linear translation.

6. The motor direct drive pump of claim 5, wherein, The side wall of the piston assembly (50) is a cylindrical surface, and the piston assembly (50) is provided with a notch (501); The eccentric driving part (4011) arranged at the end of the main shaft (401) is used for inserting the notch (501) and driving the piston assembly (50) to translate; Alternatively, the piston assembly (50) comprises a piston head and a piston connecting rod, one end of the piston connecting rod is hingedly connected to the eccentric driving part (4011), and the other end is hingedly connected to the piston head.

7. The motor direct drive pump of claim 6, wherein, The main shaft (401) is provided with an eccentric weight (4012), and the center of gravity of the eccentric weight (4012) and the center of gravity of the eccentric driving part (4011) are symmetrical about the axis of the main shaft (401).

8. The motor direct drive pump of claim 6, wherein, The housing assembly (10) is provided with two piston cavities (101), and the piston assembly (50) alternately works in the two piston cavities (101).

9. The motor direct drive pump of claim 6, wherein, The eccentric driving part (4011) is sleeved with a third bearing (404).

10. The pump of claim 1, wherein, The connecting disc (301) comprises a center part (3011), a connecting part (3012) and a surrounding part (3013), the connecting part (3012) extends radially, and two ends of the connecting part (3012) are fixed to the center part (3011) and the surrounding part (3013) respectively. The connecting part (3012) is distributed radially around the center part (3011).

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