CN117345574A - Digital flow distribution and speed regulation type low-speed axial plunger pump - Google Patents

Abstract

The invention discloses a digital flow distribution and speed regulating low-speed axial piston pump, which relates to the technical field of hydraulic pumps and includes a pump body, an input shaft, a swash plate, an axial piston, a spring, a through shaft, an encoder and a controller. When the pump enters the working state, the input shaft drives the swash plate to rotate. The rotation of the swash plate causes the sliding shoe to swing and move axially, causing the axial plunger to move axially. When the axial plunger moves axially, it passes through the plunger cavity. The change in volume except the axial plunger cooperates with the opening and closing of the two-position two-way solenoid valve to complete oil suction and oil discharge: the controller measures and calculates the angle and angular velocity of the input shaft based on the signal fed back by the encoder, and determines whether to open or close the valve. The timing to close the 2-position 2-way solenoid valve. The digital flow distribution and speed regulating low-speed axial piston pump of the present invention can improve the volumetric efficiency and life of the axial piston pump, enhance the heat dissipation of the internal components of the pump, and make the pump body structure more compact.

Description

A digital flow distribution and speed regulating low-speed axial piston pump

Technical field

The invention relates to the technical field of hydraulic pumps, and in particular to a digital flow distribution and speed regulating low-speed axial piston pump.

Background technique

In recent years, hydraulic power generation technology has been used in new energy power generation fields such as wind energy and ocean energy. The traditional hydraulic power generation structure uses a "quantitative hydraulic pump-variable hydraulic motor" circuit to collect wind energy or ocean energy. Among them, the hydraulic pump generally adopts a quantitative hydraulic pump designed according to the constant high speed driving principle. When working under random low-speed input conditions such as wind power generation and ocean energy power generation, it is difficult for this type of high-speed quantitative hydraulic pump to maintain the characteristics of high performance, strong adaptability, long life, and convenient operation and maintenance.

The axial piston hydraulic pump has a compact structure and high volumetric efficiency at high speeds. It is one of the commonly used hydraulic pumps. When the input spindle rotates once, each plunger reciprocates once. In order to correctly complete the oil suction and oil discharge work, distribution plate flow distribution or valve flow distribution technology is usually used. In the plate distribution structure, the plunger group rotates with the input shaft, and the swash plate and valve plate are stationary. The inclination of the swash plate can be adjusted through the mechanism to achieve the purpose of variable displacement. In the valve distribution structure, the swash plate rotates with the input shaft, and the plunger group only performs reciprocating motion. The opening and closing of the solenoid valve is used to switch the oil suction and oil discharge areas. If closed-loop control of the pump displacement is required based on external input speed, both of the above methods require the addition of additional feedback devices.

In addition, whether it is plate flow distribution or valve flow distribution, hydrostatic support is mostly used for lubrication between the sliding shoe and the swash plate. That is, the plunger cavity is slotted to communicate with the inner cavity of the sliding shoe, and high-pressure leakage oil is used to rub the sliding shoe of the swash plate. The deputy performs lubrication and cooling. This form of slotting will lead to a reduction in volumetric efficiency, and a small amount of leaked oil will have a poor cooling effect on the internal components of the pump, which will lead to significant heating of each kinematic pair when the plunger pump continues to operate. In addition, when used in random low-speed input conditions of wind power generation and ocean energy power generation, opening a drain tank will further reduce the volumetric efficiency of the axial piston pump, which leads to a decrease in pump performance and energy conversion efficiency.

Patent CN110848126A discloses a plunger-type digital pump, which includes a flow distribution end cover, a housing, a low-pressure valve body, a high-pressure valve body, a cylinder, a roller plunger, a flow distribution bearing and an end cover. It controls 9 low-pressure valve bodies evenly spaced on the cylinder through electrical signals, which can realize the output flow adjustment function of the pump. Its flow distribution function is realized by the flow distribution slide fixed on the input shaft. It is essentially a mechanical flow distribution. Therefore, it does not have the detection function of the input shaft rotation angle and angular velocity. An external feedback device is required to realize the closed-loop speed regulation function, and the slide The shoe also adopts the traditional hydrostatic support form of the drain tank, which results in larger leakage at low speeds.

Patent CN106321393A discloses an axial piston pump with automatic displacement compensation and variable speed adjustment swash plate, which includes a cylinder, a plunger, a plunger sleeve and a conical spring arranged in the plunger pump. When the rotation speed is as low as a threshold, It can automatically increase the displacement, which broadens the low speed limit of the pump to a certain extent. However, since it is a mechanical displacement adjustment, it does not completely solve the problem of internal leakage of the pump. Moreover, the pump itself does not have a speed regulation function under low-speed conditions.

Patent CN113107800A discloses a forced self-cooling oblique-axis axial piston pump with oil inlet in the casing. The oil inlet is also on the casing. The cool oil sucked in directly cools the two pairs of friction pairs and many transmission pairs in the pump. To achieve the purpose of lowering the pump temperature and increasing the service life. However, this design only improves the heat dissipation performance of the pump and does not use this to further optimize the internal leakage problem of the sliding shoe swash plate. Therefore, the volumetric efficiency of the pump is low under low-speed conditions.

Patent CN105386953B discloses a digital flow distribution constant flow radial piston pump, which mainly includes a plunger chamber, a two-position three-way high-speed switching valve connecting the oil tank and the load, an absolute angle encoder connected to the crankshaft of the plunger chamber, Equipped with fluid and controller. It receives the input shaft angle signal and then realizes variable control of the pump through duty cycle control. However, its inlet and outlet oil passages are all on the distribution body, and the sliding shoes still use the traditional hydrostatic support form of the drain tank. Therefore, the problem of reduced volumetric efficiency caused by internal leakage under low-speed operation still exists.

In summary, there is still room for optimization design of axial piston pumps used in random low-speed input conditions.

Contents of the invention

The purpose of the present invention is to provide a low-speed axial piston pump with digital flow distribution and speed regulation to solve the problems existing in the above-mentioned prior art, improve the volumetric efficiency and life of the axial piston pump, and enhance the heat dissipation of the internal components of the pump. Make the pump body structure more compact.

In order to achieve the above objects, the present invention provides the following solutions:

The invention provides a digital flow distribution and speed regulating low-speed axial piston pump, which includes:

The pump body is provided with an oil storage cavity and an oil through hole. The pump body is also provided with an oil inlet and an oil outlet. One end of the oil through hole and the oil inlet are respectively connected with the oil inlet. The oil storage chambers are connected;

Input shaft, the input shaft rotates with the pump body, the input shaft is used to connect the driving device, and one end of the input shaft extends into the oil storage cavity;

A swash plate located in the oil storage cavity, the center of one side of the swash plate is fixedly connected to one end of the input shaft extending into the oil storage cavity;

a sliding shoe with a first side in contact with the other side of the swash plate;

A plurality of axial plungers are evenly distributed in the circumferential direction with the axial direction of the input shaft as the central axis. The axis of the axial plunger is parallel to the axis of the input shaft. The pump body corresponds to each of the shafts. Each plunger is provided with a plunger cavity, the axial plunger is in sliding fit with the corresponding plunger cavity, and the circumferential side wall of the axial plunger is sealed with the inner wall of the plunger cavity. , and one end of each axial plunger is rotationally matched with the second side of the sliding shoe;

A plurality of springs, the springs, the axial plunger and the plunger cavity correspond one to one, one end of the spring is in contact with the end of the axial plunger away from the sliding shoe, and the other end is in contact with the One end of the plunger cavity away from the sliding shoe abuts;

A flow channel corresponding to the plunger cavity. One end of the flow channel is connected to the corresponding plunger cavity, and the other end is connected to the oil outlet through a one-way valve. The middle part of the flow channel is connected through two The two-way solenoid valve is connected to the other end of the oil hole;

A through shaft that passes through the oil hole and is coaxial with the input shaft. The through shaft rotates with the pump body. One end of the oil hole extends into the oil storage cavity with the input shaft. The inner end is fixed;

An encoder, the encoder is connected to one end of the through shaft extending out of the pump body;

A controller, the encoder and each of the two-position two-way solenoid valves are electrically connected to the controller, and the controller is used to control any one of the two-position two-way solenoid valves according to the signal fed back by the encoder. Valve opening and closing.

Preferably, the swash plate rotates with the pump body through a first bearing, and the through shaft rotates with the pump body through two second bearings; the digital flow distribution and the speed-adjustable low-speed axial plunger When the pump is operating normally, one end of the input shaft extends into the pump body, one end of the axial plunger is close to the sliding shoe, the swash plate, the sliding shoe and the first bearing are all immersed in the In the oil in the oil storage cavity, the two second bearings are immersed in the oil in the oil passage hole.

Preferably, the first side of the sliding shoe is provided with a guide groove, and the guide groove penetrates the outer edge and the inner edge of the first side of the sliding shoe.

Preferably, the pump body is further provided with a maintenance oil drain port connected to the oil storage chamber.

Preferably, one end of the axial plunger close to the sliding shoe is provided with a ball head, and the second side of the sliding shoe is provided with a spherical concave surface corresponding to the ball head, and the ball head is in contact with the corresponding spherical concave surface. Turn to fit.

Preferably, the sliding shoe is provided with an oil guide hole corresponding to each of the spherical concave surfaces, and the spherical concave surfaces communicate with the oil storage cavity through the oil guide holes.

Preferably, the material of the sliding shoe is gradient structure cemented carbide.

Preferably, the pump body is provided with an observation window through which the oil storage chamber can be observed.

Compared with the prior art, the present invention achieves the following technical effects:

The digital flow distribution and speed regulating low-speed axial piston pump of the present invention can improve the volumetric efficiency and life of the axial piston pump, enhance the heat dissipation of the internal components of the pump, and make the pump body structure more compact.

Furthermore, the digital flow distribution and speed-regulating low-speed axial piston pump of the present invention transmits the angle and speed information of the input shaft to the tail-end controller in the form of a through-shaft, and then controls the valve group to form a closed loop in the pump. Flow distribution and speed regulation functions.

Furthermore, the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention stores hydraulic oil in the oil storage cavity of the pump body, eliminating the need for an external oil tank and making the hydraulic system more compact. Hydraulic oil stored in the pump can be used as lubricating oil and cooling oil. On the one hand, it increases the lubrication between the components in the pump, reduces the failure rate of components and increases the service life of the pump; on the other hand, it is beneficial to the maintenance of the pump body. Dissipate heat and cool down to avoid reduction in work efficiency, lubrication performance and service life of hydraulic oil caused by excessive temperature of hydraulic oil.

Furthermore, by changing the flow path, lubrication method and control method, the drain groove in the traditional plunger pump is eliminated. This increases the volumetric efficiency and work efficiency of the pump, and reduces the processing difficulty and accuracy of the axial plunger and sliding shoe. Therefore, materials with stronger mechanical properties but not easy to process can be used to manufacture the axial plunger and sliding shoe, thereby further increasing the life of the pump and enhancing its adaptability.

Furthermore, diversion grooves are used to enhance the stiffness of the oil film between the sliding shoe and the distribution plate, thereby enhancing the lubrication effect. The new ordered flow guide texture enables the sliding shoe to absorb hydraulic oil for lubrication under different motion states. At the same time, different guide groove width designs can also make the end face of the sliding shoe have more uniform oil film stiffness and lubrication performance.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention;

Figure 2 is a schematic structural diagram of the sliding shoe in the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention;

Figure 3 is a partial structural schematic diagram of the sliding shoe in the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention;

Figure 4 is a schematic diagram of the enhanced gradient distribution method of the sliding shoe in the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention;

Figure 5 is a control logic diagram of a single flow channel in the digital flow distribution and speed-adjustable low-speed axial piston pump of the present invention;

Among them, 1. Input shaft; 2. Swash plate; 3. Observation window; 4. Sliding shoe; 5. Oil inlet; 6. Axial plunger; 7. Two-position two-way solenoid valve; 8. One-way valve; 9. Oil outlet; 10. Oil storage chamber; 11. Maintenance oil drain; 12. Through shaft; 13. Controller; 14. Plunger chamber; 15. Oil hole; 16. Flow channel; 17. Guide Flow groove; 18. Spherical concave surface; 19. Oil guide hole; 20. First bearing; 21. Second bearing.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The purpose of the present invention is to provide a low-speed axial piston pump with digital flow distribution and speed regulation to solve the problems existing in the above-mentioned prior art, improve the volumetric efficiency and life of the axial piston pump, and enhance the heat dissipation of the internal components of the pump. Make the pump body structure more compact.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1 to 4, this embodiment provides a digital flow distribution and speed regulating low-speed axial piston pump, including a pump body, an input shaft 1, a swash plate 2, an axial plunger 6, a spring, and a through shaft. 12. Encoder and controller 13.

Among them, the pump body is provided with an oil storage chamber 10 and an oil through hole 15. The pump body is also provided with an oil inlet 5 and an oil outlet 9. One end of the oil through hole 15 and the oil inlet 5 are connected to the oil storage chamber respectively. 10 is connected, the hydraulic oil enters the oil storage chamber 10 from the oil inlet 5 and fills 70%-95% of the oil storage chamber 10. The hydraulic oil is stored in the oil storage chamber 10 rather than in an external oil tank. Therefore, when the hydraulic oil circulates, it does not need to pass through the external oil tank. It only needs to be filtered after the hydraulic oil leaves the external oil tank and before entering the oil storage chamber 10 in the pump body.

The input shaft 1 rotates with the pump body, and is used to connect the driving device. One end of the input shaft 1 extends into the oil storage chamber 10, and the input shaft 1 is driven to rotate by the driving device.

Both the swash plate 2 and the sliding shoe 4 are located in the oil storage cavity 10. The center of one side of the swash plate 2 is fixedly connected to the end of the input shaft 1 that extends into the oil storage cavity 10; the first side of the sliding shoe 4 (i.e., Figure The left side in 1) is in contact with the other side of the swash plate 2.

The first side of the sliding shoe 4 is also provided with a guide groove 17 , and the guide groove 17 penetrates the outer edge and the inner edge of the first side of the sliding shoe 4 . The function of the guide groove 17 is to guide the hydraulic oil in the oil storage chamber 10 to the contact surface between the sliding shoe 4 and the swash plate 2, thereby improving the friction coefficient between the sliding shoe 4 and the swash plate 2 and reducing friction loss. ; It is worth noting that the specific shape or pattern of the guide groove can be designed adaptively according to actual needs, as long as the hydraulic oil in the oil storage chamber 10 can be guided to the contact surface between the sliding shoe 4 and the swash plate 2 As shown in Figure 2, this embodiment provides a specific form of the guide groove 17. The guide groove 17 in Figure 2 is divided into two inner and outer circles, and the outer circle is composed of 12 pairs of clockwise and counterclockwise Aki. It is composed of Meade spirals. The starting angles of the two are the same. The inner ring is composed of two pairs of orthogonal straight lines. The width of the guide groove 17 of the outer ring is greater than the width of the inner ring to ensure that the inner ring and the outer ring have an approximate coverage ratio. The depth of groove 17 is 0.5-1mm.

There are multiple axial plungers 6 . In practical applications, the number of axial plungers 6 can be adjusted adaptively according to actual needs. In this embodiment, the number of axial plungers 6 is five. All the axial plungers 6 are evenly distributed in the circumferential direction with the axial direction of the input shaft 1 as the central axis. The axis of the axial plunger 6 is parallel to the axis of the input shaft 1. , a plunger chamber 14 is provided corresponding to each axial plunger 6 in the pump body. The axial plunger 6 slides with the corresponding plunger chamber 14. The circumferential side wall of the axial plunger 6 is in contact with the plunger chamber 14. There is a seal between the inner walls, and one end of each axial plunger 6 is rotationally matched with the second side of the sliding shoe 4 (ie, the right side in Figure 1). Specifically:

The axial plunger 6 is provided with a ball head at one end close to the sliding shoe 4. The second side of the sliding shoe 4 is provided with a spherical concave surface 18 corresponding to the ball head, and the ball head rotates with the corresponding spherical concave surface 18. Six oil guide holes 19 are provided on the sliding shoe 4 corresponding to each spherical concave surface 18. The spherical concave surface 18 communicates with the oil storage chamber 10 through the oil guide holes 19. The center line of the oil guide hole 19 passes through the center of the spherical concave surface 18, and the diameter of the oil guide hole 19 is no more than 5 mm; the design of the oil guide hole 19 reduces the friction between the spherical concave surface 18 and the ball head.

The spring, the axial plunger 6 and the plunger chamber 14 correspond one to one. The spring is located in the plunger chamber 14. One end of the spring is in contact with the end of the axial plunger 6 away from the sliding shoe 4, and the other end of the spring is away from the plunger chamber 14. One end of the shoe 4 is in contact; under the elastic force of the spring, a force is given to the axial plunger 6 so that the first side of the sliding shoe 4 is always in close contact with the swash plate 2 .

This embodiment of the digital flow distribution and speed-adjustable low-speed axial piston pump also includes a flow channel 16 corresponding to the plunger cavity 14. Based on the perspective of Figure 1, the left end of the flow channel 16 is connected to the corresponding plunger cavity 14. , the right end is connected to the oil outlet 9 through the one-way valve 8, and the middle part of the flow channel 16 is connected to the right end of the oil hole 15 through the two-position two-way solenoid valve 7.

The through shaft 12 passes through the oil through hole 15 and is coaxial with the input shaft 1. The through shaft 12 rotates with the pump body. One end of the oil through hole 15 is fixedly connected to the end of the input shaft 1 that extends into the oil storage chamber 10; the encoder It is connected to the end of the through shaft 12 extending out of the pump body; when the driving device drives the input shaft 1 to rotate, the input shaft 1 drives the coaxial axis to rotate together, and the encoder can convert the rotational displacement of the through shaft 12 into a series of digital pulse signals.

The swash plate 2 rotates with the pump body through the first bearing 20, and the through shaft rotates with the pump body through the two second bearings 21; when the digital flow distribution and speed regulating low-speed axial piston pump of this embodiment is working normally, the input The end of the shaft 1 extending into the pump body, the end of the axial plunger 6 close to the sliding shoe 4, the swash plate 2, the sliding shoe 4 and the first bearing 20 are all immersed in the oil in the oil storage chamber 10. The second bearing 21 is immersed in the oil in the oil hole 15 .

The pump body is provided with an observation window 3, through which the oil storage chamber 10 can be observed. When the pump is in working condition, the operator can observe the conditions inside the oil storage chamber 10 through the observation window 3. The pump body is also provided with a maintenance oil drain port 11 connected with the oil storage chamber 10. When disassembly or maintenance is required, the hydraulic oil can be released from the maintenance oil drain port 11.

In order to increase the surface hardness and wear resistance of the end surface of the sliding shoe 4, the material of the sliding shoe 4 is gradient structure cemented carbide, and its reinforcing phase can be tin, aluminum or manganese, etc. The distribution density of the reinforcing phase of the sliding shoe 4 is shown in Figure 4 As shown, the direction decreases along the surface of the vertical sliding shoe 4 toward the spherical concave surface 18 .

The encoder and each two-position two-way solenoid valve 7 are electrically connected to the controller 13. The controller 13 is used to control the opening and closing of any two-position two-way solenoid valve 7 according to the signal fed back by the encoder. The controller 13 measures and calculates the angle and angular velocity of the input shaft 1 based on the signal fed back by the encoder, and determines the timing of opening and closing the two-position two-way solenoid valve 7 .

The specific working principle of the digital flow distribution and speed-adjustable low-speed axial piston pump in this embodiment is as follows:

When the pump enters the working state, the input shaft 1 drives the swash plate 2 to rotate, and the rotation of the swash plate 2 causes the sliding shoe 4 to swing and move axially, causing the axial plunger 6 to move axially, and the axial plunger 6 moves axially. During movement, the oil suction and oil discharge are completed through the change of the volume in the plunger chamber 14 except the axial plunger 6 and the opening and closing of the two-position two-way solenoid valve 7.

Taking the working process of a single flow channel 16 as an example, as shown in Figure 1 and Figure 5, when the axial plunger 6 extends to the left, the two-position two-way solenoid valve 7 opens, and the plunger chamber 14 and the oil passage hole 15 is connected, at this time the one-way valve 8 automatically closes, blocking this flow path branch from being affected by the pressure changes of other flow path branches. The hydraulic oil in the oil storage chamber 10 enters the plunger chamber 14 through the oil passage hole 15, and the completion Oil sucking action. When the axial plunger 6 moves to the right, that is, when it is pushed into the plunger chamber 14, the pressure in the chamber on the right side of the axial plunger 6 increases. At this time, if the two-position two-way solenoid valve 7 is closed, the plunger The cavity 14 is disconnected from the oil hole 15, and the one-way valve 8 will automatically open under the action of high pressure, and the hydraulic oil will enter the external load through the oil outlet 9 to complete the oil discharge action; if the two-position two-way solenoid valve 7 is still open, then The plunger chamber 14 is connected with the oil hole 15, and since the pressure in the oil storage chamber 10 and the oil hole 15 is very low, and the oil pressure of the external load is high, the one-way valve 8 will be closed under the action of its own spring. Keeping it closed, the hydraulic oil in the plunger chamber 14 will be discharged back into the oil storage chamber 10 through the oil passage hole 15, completing the no-load action.

Specific examples are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, based on this The idea of the invention will be subject to change in the specific implementation and scope of application. In summary, the contents of this description should not be construed as limitations of the present invention.

Claims (8)

1. A digital flow distribution and speed regulating low-speed axial piston pump, which is characterized by including: The pump body is provided with an oil storage cavity and an oil through hole. The pump body is also provided with an oil inlet and an oil outlet. One end of the oil through hole and the oil inlet are respectively connected with the oil inlet. The oil storage chambers are connected; Input shaft, the input shaft rotates with the pump body, the input shaft is used to connect the driving device, and one end of the input shaft extends into the oil storage cavity; A swash plate located in the oil storage cavity, the center of one side of the swash plate is fixedly connected to one end of the input shaft extending into the oil storage cavity; a sliding shoe with a first side in contact with the other side of the swash plate; A plurality of axial plungers are evenly distributed in the circumferential direction with the axial direction of the input shaft as the central axis. The axis of the axial plunger is parallel to the axis of the input shaft. The pump body corresponds to each of the shafts. Each plunger is provided with a plunger cavity, the axial plunger is in sliding fit with the corresponding plunger cavity, and the circumferential side wall of the axial plunger is sealed with the inner wall of the plunger cavity. , and one end of each axial plunger is rotationally matched with the second side of the sliding shoe; A plurality of springs, the springs, the axial plunger and the plunger cavity correspond one to one, one end of the spring is in contact with the end of the axial plunger away from the sliding shoe, and the other end is in contact with the One end of the plunger cavity away from the sliding shoe abuts; A flow channel corresponding to the plunger cavity. One end of the flow channel is connected to the corresponding plunger cavity, and the other end is connected to the oil outlet through a one-way valve. The middle part of the flow channel is connected through two The two-way solenoid valve is connected to the other end of the oil hole; A through shaft that passes through the oil hole and is coaxial with the input shaft. The through shaft rotates with the pump body. One end of the oil hole extends into the oil storage cavity with the input shaft. The inner end is fixed; An encoder, the encoder is connected to one end of the through shaft extending out of the pump body; A controller, the encoder and each of the two-position two-way solenoid valves are electrically connected to the controller, and the controller is used to control any one of the two-position two-way solenoid valves according to the signal fed back by the encoder. Valve opening and closing. 2. The digital flow distribution and speed regulating low-speed axial piston pump according to claim 1, characterized in that: the swash plate rotates with the pump body through a first bearing, and the through shaft passes through two second bearings. The two bearings rotate with the pump body; when the digital flow distribution and speed-adjustable low-speed axial piston pump works normally, the input shaft extends into one end of the pump body, and the axial plunger is close to the One end of the sliding shoe, the swash plate, the sliding shoe and the first bearing are all immersed in the oil in the oil storage chamber, and the two second bearings are immersed in the oil holes. in the oil. 3. The digital flow distribution and speed-regulating low-speed axial piston pump according to claim 1, characterized in that: the first side of the sliding shoe is provided with a flow guide groove, and the flow guide groove penetrates the slide shoe. The outer and inner edges of the first side of the boot. 4. The low-speed axial piston pump with digital flow distribution and speed regulation according to claim 1, characterized in that: the pump body is further provided with a maintenance oil drain port connected to the oil storage chamber. 5. The low-speed axial piston pump with digital flow distribution and speed regulation according to claim 1, characterized in that: the axial plunger is provided with a ball head at one end close to the sliding shoe, and the third end of the sliding shoe is provided with a ball head. Two sides are provided with spherical concave surfaces corresponding to the ball heads, and the ball heads are rotationally matched with the corresponding spherical concave surfaces. 6. The digital flow distribution and speed regulating low-speed axial piston pump according to claim 5, characterized in that: the sliding shoe is provided with an oil guide hole corresponding to each of the spherical concave surfaces, and the spherical concave surfaces pass through The oil guide hole communicates with the oil storage cavity. 7. The digital flow distribution and speed regulating low-speed axial piston pump according to claim 1, characterized in that: the material of the sliding shoe is gradient structure cemented carbide. 8. The digital flow distribution and speed regulating low-speed axial piston pump according to claim 1, characterized in that: the pump body is provided with an observation window, and the oil storage chamber can be observed through the observation window. .