CN111946580B

CN111946580B - Digital variable hydraulic motor radial plunger pump

Info

Publication number: CN111946580B
Application number: CN202010862662.5A
Authority: CN
Inventors: 冀宏; 孙飞; 汤荣福; 刘耀卓; 白宇杰; 闵为; 邢晖晖
Original assignee: Lanzhou University of Technology
Current assignee: Lanzhou University of Technology
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2021-04-09
Anticipated expiration: 2040-08-25
Also published as: CN111946580A

Abstract

A motor rotor (15) is sleeved on a hollow composite shaft (8) in a hot mode and supported inside a shell (12) through bearings (19 and 27), and sealing rings (20), sealing rings (26) and lip-shaped sealing rings (25) are arranged on two sides of the bearings; the ball plunger (5) and the sliding shoe (6) are rolled into a whole and connected in a spherical hinge, the axis of the ball plunger (5) is vertical to the axis of the hollow composite shaft (8), the sliding shoe (6) is in contact fit with an eccentric disc (8 c) on the hollow composite shaft (8), and when the eccentric disc (8 c) rotates along with the hollow composite shaft (8), the ball plunger (5) and the sliding shoe (6) are driven to move in a corresponding plunger hole (10 c) formed in the pump body (10) and reset under the action of the reset spring (4); the axis of the digital switch oil suction one-way valve (1) is coincided with the axis of the plunger hole (10 c), and the oil discharge one-way valve (3) is arranged perpendicular to the electromagnetic switch oil suction one-way valve (1).

Description

Digital variable hydraulic motor radial plunger pump

Technical Field

The invention relates to an electro-hydraulic integrated hydraulic power unit technology, in particular to a digital variable hydraulic motor radial plunger pump.

Background

The electro-hydraulic integrated hydraulic power unit is a new development direction of current hydraulic power equipment, and is rapidly developed in international and domestic markets with the great advantages of low noise, high efficiency, compact structure, man-machine friendliness and the like. The prior art mainly focuses on the integration of a quantitative hydraulic pump and a motor, such as a hydraulic motor vane pump of Eton in America, an electro-hydraulic integrated skewed tooth pump of Leishile in Germany, an air gap non-oil-immersed hydraulic motor vane pump developed by the university of Ritudinners in Lanzhou, and the like. In the occasions with high working pressure, even ultrahigh pressure and strict requirement on axial dimension, the quantitative radial plunger pump is widely applied by the unique structural advantages, along with the development of hydraulic technology, in a hydraulic system with continuously changing flow demand, a variable radial plunger pump is produced, for example, a multi-row multi-action inner curve rotor driving digital variable radial plunger pump (CN 109236595A), an unloading type independent variable radial plunger pump (CN 106640576B), a radial plunger pump (CN 104929885A) and the like are patented, the invention related to the patents are all provided with an oil suction one-way valve, an oil discharge one-way valve and a high-speed digital switch valve/reversing valve so as to realize the oil suction and discharge functions of the pump, and the control and regulation of the pump from the maximum displacement to the zero displacement are realized by actively controlling the opening and closing states and the opening and closing sequence of a valve port of the high-speed digital switch valve.

To summarize the technical deficiencies: 1. the number of related parts/elements is large, and the structure is relatively complex; 2. the motor is cooled by air, so that the noise is high, or a water-cooling/oil-cooling motor is adopted, but an additional cooling system is needed, so that the system complexity is increased; 3. the problem of insufficient oil absorption, particularly low volumetric efficiency and total efficiency caused by high rotating speed exists. 4. The rotor and the plunger friction pair are not lubricated by oil liquid, and the friction and the abrasion are large; 5. the bearing can only be sealed by grease, and the service life is limited; 6. the shaft seal has external leakage and potential risk of environmental pollution; 7. the motor is still connected with a shaft coupler, the axial size is still large, and the whole volume and weight are large.

Disclosure of Invention

The invention aims to provide a radial plunger pump of a digital variable hydraulic motor.

The invention relates to a digital variable hydraulic motor radial plunger pump which comprises a digital switch oil suction one-way valve 1, a safety valve 2, an oil discharge one-way valve 3, a return spring 4, a ball plunger 5, a sliding shoe 6, a front end cover 7, a hollow composite shaft 8, a sliding bearing 9, a pump body 10, a positioning pin 11, a shell 12, an oil discharge plug 13, a motor stator 14, a motor rotor 15, an inner end cover 16, a rotating speed sensor 17, a first spring retainer ring 18, a first bearing 19, a first sealing ring 20, a position sensor 21, a rear end cover 22, a sealing gasket 23, a lifting lug 24, a lip-shaped sealing ring 25, a second sealing ring 26, a second bearing 27, an air discharge plug 28 and a second spring retainer ring 29. The motor rotor 15 is a permanent magnet rotor, is sleeved on the hollow composite shaft 8 in a hot manner, and is supported in the shell 12 by a first bearing 19 and a second bearing 27, and a first sealing ring 20, a second sealing ring 26 and a lip-shaped sealing ring 25 are arranged on two sides of the bearing; the hollow composite shaft 8 is an integrated body of a motor main shaft, a radial plunger pump main shaft and a liquid-filled centrifugal pump, the ball plunger 5 and the slipper 6 are rolled into a whole and connected in a spherical hinge, the axis of the ball plunger 5 is vertical to the axis of the hollow composite shaft 8, the slipper 6 is in contact fit with an eccentric disc 8d on the hollow composite shaft 8, and when the eccentric disc 8d rotates along with the hollow composite shaft 8, the ball plunger 5 and the slipper 6 are driven to move in a corresponding plunger hole 10c formed in the pump body 10 and reset under the action of the reset spring 4; the digital switch oil suction one-way valve 1 is an integrated body of the digital switch valve and the oil suction one-way valve, the axis of the digital switch oil suction one-way valve 1 is overlapped with the axis of the plunger hole 10c, and the oil discharge one-way valve 3 is arranged perpendicular to the digital switch oil suction one-way valve 1; the digital switch oil suction one-way valve 1 and the oil discharge one-way valve 3 are combined in a pair and periodically and asynchronously open and close along with pressure change to form a high-low pressure cavity of the pump; the rotating speed sensor 17 and the position sensor 21 are arranged on the inner end cover 16, and probe parts of the rotating speed sensor and the position sensor are opposite to the magnetic steel of the motor rotor 15; the safety valve 2 is arranged in a threaded hole 7d on the front end cover 7, the inlet of the safety valve is communicated with the oil drain port 7c, and the outlet of the safety valve is communicated with a safety valve oil return hole 1 (7 e); the pump body 10 and the front end cover 7 are positioned by a positioning pin 11, and the O-shaped sealing ring I, O, the O-shaped sealing ring II and the O-shaped sealing ring III are sealed and fixed on the shell 12 through screws.

The invention has the advantages that: the digital variable hydraulic motor radial plunger pump has the following advantages:

1. high efficiency: a) the liquid-filled centrifugal pump is a radial plunger pump for pressurizing and supplying liquid, and can ensure that the liquid is fully absorbed even at a high rotating speed;

b) the adjustable range of the displacement is large, the power adaptability is good, and the energy conversion efficiency is high;

c) the radial plunger pump rotor cavity is communicated with the oil suction way, so that lip-shaped sealing is omitted, a sliding bearing, a sliding shoe and eccentric disc friction pair and a ball plunger and sliding shoe friction pair are fully lubricated, and the friction loss is small;

d) the pump shaft of the radial plunger and the motor shaft are integrated, so that mechanical connection is omitted, and energy transmission loss is avoided;

e) the flowing hydraulic oil is cooled, the heat dissipation is sufficient, and the energy loss is small.

2. The adjustable range of the discharge capacity is large, and the adjusting precision is high: a) the variable rotating speed is adjusted, the position sensor and the rotating speed sensor are used for monitoring in real time, and the motor controller is used for accurately controlling the rotating speed. b) The oil suction one-way valve is controlled to be opened and closed through the electric control digital switch, the control precision is high, and the adjustable range is larger as the number of the plungers is larger; c) the two are combined for adjustment.

3. Low noise: a) hydraulic oil cooling replaces air cooling, and noise is greatly reduced; b) the pump can fully absorb oil, and the cavitation noise is low; c) the transmission shaft is not mechanically connected.

4. The volume is small: the permanent magnet motor, the radial plunger pump, the liquid-filled centrifugal pump, the digital switch valve and the safety valve are integrated, a cooling fan, a coupler and the like are omitted, and the rotating speed sensor and the position sensor are integrally installed on the inner end cover, so that the structure is extremely compact.

5. The working pressure is high: under the working condition of small displacement, the pressure can reach an ultrahigh pressure level.

6. A variety of media are suitable: except for the conventional hydraulic oil, the hydraulic oil can be suitable for low-viscosity media such as water and the like only by slightly changing the structure and the materials.

7. No external leakage: the hollow composite shaft has no outward extension, and the external leakage is completely avoided.

8. Is safe and reliable. The integrated relief valve ensures that the outlet pressure is constant when the pressure is abnormal, and avoids overload operation.

Drawings

Fig. 1 is a schematic structural view of the present invention, fig. 2 is a sectional view of a hollow composite shaft 8, fig. 3 is an enlarged view of B in fig. 1, fig. 4 is an enlarged view of a in fig. 1, fig. 5 is a distribution view of a ball plunger 5 and a slipper 6, fig. 6 is a sectional view of a pump body 10 and a front cover 7, and fig. 7 is a left side view of fig. 6; reference numerals and corresponding names: the oil-suction digital switch check valve comprises a digital switch oil-suction check valve 1, a valve body 1a, a digital switch valve guide rod 1b, a steel ball 1c, a combined sealing ring 1d, a spring 1e, a spring seat 1f, a combined sealing gasket 1g, a combined sealing gasket 1i, a digital switch valve body 1j, a safety valve 2, a combined sealing ring 2a, a combined sealing gasket 2b, an oil discharge check valve 3, a reset spring 4, a ball plunger 5, a sliding shoe 6, an oil hole 6a and an oil groove 6b, a front end cover 7, a high-pressure oil collecting tank 7a, a sliding bearing mounting hole 7b, an oil discharge port 7c, a safety valve mounting threaded hole 7d, a safety valve oil return hole 1 (7 e), a hollow composite shaft 8, an inner flow passage 8a, a long and thin micropore 8b, a centrifuge tube 8c, an eccentric disc 8d, a sliding bearing 9, a pump body 10, a pump oil-suction hole 10, The oil-gas separator comprises an annular cavity 10e, an oil discharge one-way valve mounting hole 10f, a safety valve oil return hole 2 (10 g), a through hole 10h, a positioning pin 11, a shell 12, an inlet 12a, a rectangular flow channel 12b, a heat dissipation rib 12c, a low-pressure oil collection cavity 12d, an oil drain plug 13, a motor stator 14, a motor rotor 15, an inner end cover 16, a rotating speed sensor 17, a first spring retainer ring 18, a first bearing 19, a first sealing ring 20, a position sensor 21, a rear end cover 22, a sealing gasket 23, a lifting lug 24, a lip-shaped sealing ring 25, a second sealing ring 26, a second bearing 27, an air discharge plug 28, a second spring retainer ring 29, an O-shaped sealing ring I, O type sealing ring II and an.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

As shown in fig. 1 to 7, the invention relates to a digital variable hydraulic motor radial plunger pump, which integrates a permanent magnet motor, a radial plunger pump, a liquid-filled centrifugal pump, a digital switch valve and a safety valve, and comprises a digital switch oil suction one-way valve 1, a safety valve 2, an oil discharge one-way valve 3, a return spring 4, a ball plunger 5, a sliding shoe 6, a front end cover 7, a hollow composite shaft 8, a sliding bearing 9, a pump body 10, a positioning pin 11, a shell 12, an oil discharge plug 13, a motor stator 14, a motor rotor 15, an inner end cover 16, a rotation speed sensor 17, a first spring retainer ring 18, a first bearing 19, a first seal ring 20, a position sensor 21, a rear end cover 22, a seal gasket 23, a lifting lug 24, a lip seal ring 25, a second seal ring 26, a second bearing 27, a gas discharge plug 28 and a second spring retainer. The motor rotor 15 is a permanent magnet rotor, is sleeved on the hollow composite shaft 8 in a hot mode, is supported inside the shell 12 through a first bearing 19 and a second bearing 27, and is provided with a first sealing ring 20, a second sealing ring 26 and a lip-shaped sealing ring 25 at two sides; the hollow composite shaft 8 is an integrated body of a motor main shaft, a radial plunger pump main shaft and a liquid-filled centrifugal pump, the ball plunger 5 and the slipper 6 are rolled into a whole and connected in a spherical hinge, the axis of the ball plunger 5 is vertical to the axis of the hollow composite shaft 8, the slipper 6 is in contact fit with an eccentric disc 8d on the hollow composite shaft 8, and when the eccentric disc 8d rotates along with the hollow composite shaft 8, the ball plunger 5 and the slipper 6 are driven to move in a corresponding plunger hole 10c formed in the pump body 10 and reset under the action of the reset spring 4; the digital switch oil suction one-way valve 1 is an integrated body of the digital switch valve and the oil suction one-way valve, the axis of the digital switch oil suction one-way valve 1 is overlapped with the axis of the plunger hole 10c, and the oil discharge one-way valve 3 is arranged perpendicular to the digital switch oil suction one-way valve 1; the digital switch oil suction one-way valve 1 and the oil discharge one-way valve 3 are combined in a pair and periodically and asynchronously open and close along with pressure change to form a high-low pressure cavity of the pump; the rotating speed sensor 17 and the position sensor 21 are arranged on the inner end cover 16, and probe parts of the rotating speed sensor and the position sensor are opposite to the magnetic steel of the motor rotor 15; the safety valve 2 is arranged in a threaded hole 7d on the front end cover 7, the inlet of the safety valve is communicated with the oil drain port 7c, and the outlet of the safety valve is communicated with a safety valve oil return hole 17 e; the pump body 10 and the front end cover 7 are positioned by a positioning pin 11, and the O-shaped sealing ring I, O, the O-shaped sealing ring II and the O-shaped sealing ring III are sealed and fixed on the shell 12 through screws.

As shown in fig. 1 to 3, the hollow composite shaft 8 is provided with an inner flow passage 8a, a thin and long micropore 8b, a centrifuge tube 8c, and an eccentric disc 8 d. The angles between the axes of the slender micropores 8b and the centrifugal tubes 8c and the axis of the hollow composite shaft 8 are 60 degrees and 45 degrees respectively, two slender micropores 8b are symmetrically arranged, and 6 centrifugal tubes 8c are uniformly distributed to form the liquid-filled centrifugal pump; the elongated micro-hole 8b is communicated with the inner flow passage 8a and a gap between the lip-shaped sealing ring 25 and a second sealing ring 26, wherein the second sealing ring 26 is a labyrinth gap seal. Under the action of centrifugal force, oil enters a gap between the lip-shaped sealing ring 25 and the second sealing ring 26 through the long and thin micropores 8b and flows to the lip of the lip-shaped sealing ring 25, the lip is fully lubricated and simultaneously plays a sealing role, the oil also enters the gap of the second sealing ring 26, the oil is always filled in the gap, and gas can be sealed even if the lip-shaped sealing ring fails.

As shown in fig. 1 and 4, the digital switch oil suction check valve 1 includes: the valve comprises a valve body 1a, a digital switch valve guide rod 1b, a steel ball 1c, a combined sealing ring 1d, a spring 1e, a spring seat 1f, a combined sealing ring 1g, a combined sealing gasket 1i and a digital switch valve body 1 j. The digital switch oil absorption one-way valve 1 is arranged in a threaded hole 10b on the pump body 10 through threads on the valve body 1a, and the spring seat 1f encapsulates a spring 1e and a steel ball 1c in the valve body 1a through threads; the valve body 1a is provided with 4 to 6 radial holes 1h which communicate with an annular cavity 10 e. Under the constant flow working condition, the rotating speed is constant, the digital switch valve oil suction one-way valve 1 is powered off, and the digital switch oil suction one-way valve 1 is changed into a conventional oil suction one-way valve to work. When the displacement is required to be changed, the number (1-5) of the oil suction one-way valves 1 of the digital switch valve is determined to be opened according to the actually required flow, at the moment, the guide rod 1b of the digital switch valve pushes away the steel ball, the plunger normally sucks oil, but a closed containing cavity cannot be formed during return stroke, the sucked oil returns to a low-pressure area, namely, the oil is discharged and is invalid corresponding to the plunger, the displacement is adjusted by combining the variable rotating speed, and the large-range displacement adjustment can be realized.

As shown in fig. 5, 6 ball plungers 5 are connected with sliding shoes 6 in a ball hinge manner, and are uniformly distributed on an eccentric disc 8d and correspond to the digital switch oil suction one-way valve 1 and the oil discharge one-way valve 3 one by one, wherein the sliding shoes 6 are in a bearing bush structure, oil holes 6a and oil grooves 6b are formed in the sliding shoes, and the ball heads of the ball plungers 5 are opposite to the oil holes 6 a. The ball plunger 5 is connected with the sliding shoe 6 in a ball hinge manner, so that the lateral force can be effectively reduced or eliminated; oil in the low-pressure area enters the oil hole 6a through the oil groove 6b to lubricate the ball plunger 5 and the sliding shoe 6 kinematic pair, and the oil in the oil groove 6b lubricates the sliding shoe 6 and the eccentric disc 8d kinematic pair.

As shown in fig. 1, 6 and 7, the pump body 10 is a regular hexagonal prism, and is provided with a pump oil suction hole 10a, a digital switch oil suction check valve installation threaded hole 10b, a plunger hole 10c, a rotor cavity 10d, an annular cavity 10e, an oil discharge check valve installation hole 10f, a safety valve oil return hole 210 g and a through hole 10h, wherein the pump oil suction hole 10a is 6 waist-shaped tapered holes and is communicated with the annular cavity 10e one by one; the rotor cavity 10d is of a regular hexagonal prism type, and 6 surfaces are respectively parallel to 6 surfaces of the pump body 10.

As shown in fig. 1 and 6, the front end cover 7 is provided with a high-pressure oil sump 7a, a sliding bearing mounting hole 7b, an oil drain 7c, a safety valve mounting threaded hole 7d and a safety valve oil return hole 7e, wherein the high-pressure oil sump 7a is communicated with the oil drain 7c and outlets of 6 discharge check valves 3; the relief valve oil return hole 17 e communicates with the pump oil pumping hole 10a through the relief valve oil return hole 210 g and the annular chamber 10 e. The oil returned by the safety valve is led to the oil absorption low-pressure area, and an oil return tank pipeline is omitted.

As shown in fig. 1, the housing 12 is provided with an oil inlet 12a, a rectangular flow passage 12b, a heat dissipation rib 12c and a low-pressure oil collection chamber 12d, wherein the rectangular flow passage 12b is axially and uniformly distributed in 4 to 6. The oil inlet 12a, the rectangular flow channel 12b, the low-pressure oil collecting cavity 12d, the inner flow channel 8a, the centrifuge tube 8c, the oil pumping hole 10a and the annular cavity 10e are communicated with each other to form a radial plunger pump oil pumping path of the digital variable hydraulic motor, and the radial plunger pump oil pumping path is communicated with the high-pressure oil collecting tank 7a and the oil discharge port 7c to form a radial plunger pump cooling oil path of the digital variable hydraulic motor.

The working process of the invention is as follows: before the radial plunger pump of the digital variable hydraulic motor is started, oil is filled inside the radial plunger pump, the air discharging plug 28 is opened for exhausting air, then the radial plunger pump is started through the external motor controller, the hollow composite shaft 8 rotates, the liquid filling centrifugal pump formed by 6 centrifuge tubes 8c drives the oil to flow forcibly, meanwhile, the eccentric disc 8d drives 6 ball plungers 5 to reciprocate in the plunger cavity 10c in a rotating mode, the digital switch oil suction one-way valve 1 and the oil discharge one-way valve 3 are matched with the ball plungers 5 to be opened and closed, a high-low pressure cavity is separated/opened, oil suction and discharge work is completed, in the process, the flowing oil brings heat generated inside the radial plunger pump of the digital variable hydraulic motor out of the flowing oil, and cooling is completed. And during variable displacement adjustment, a variable mode is selected according to the actual working condition, and optimal power matching is realized. Mode 1: the output flow is adjusted by changing the rotating speed; mode 2: the oil suction one-way valve 1 is opened and closed through the independent digital switch, the corresponding ball plunger 5 is effective in oil suction and discharge when the oil suction one-way valve 1 is closed, otherwise, the oil suction one-way valve is ineffective, and the output flow is increased or reduced; mode 3: mode 1 is adjusted in combination with mode 2. In the working process, the safety valve 2 plays a role in protection, and when the pressure is abnormal, the constant outlet pressure is ensured, and the overload operation is avoided.

Claims

1. A digital variable hydraulic motor radial plunger pump comprises a digital switch oil suction one-way valve (1), a safety valve (2), an oil discharge one-way valve (3), a reset spring (4), a ball plunger (5), a sliding shoe (6), a front end cover (7), a hollow composite shaft (8), a sliding bearing (9), a pump body (10), a positioning pin (11), a shell (12), an oil drain plug (13), a motor stator (14), a motor rotor (15), an inner end cover (16), a rotating speed sensor (17), a first spring retainer ring (18), a first bearing (19), a first sealing ring (20), a position sensor (21), a rear end cover (22), a sealing gasket (23), a lifting lug (24), a lip-shaped sealing ring (25), a second sealing ring (26), a second bearing (27), an air drain plug (28) and a second spring retainer ring (29), and is characterized in that the motor rotor (15) is a permanent magnet rotor, the heat sleeve is sleeved on the hollow composite shaft (8) and supported inside the shell (12) by a first bearing (19) and a second bearing (27), and a first sealing ring (20), a second sealing ring (26) and a lip-shaped sealing ring (25) are arranged on two sides of the bearing; the hollow composite shaft (8) is an integrated body of a motor main shaft, a radial plunger pump main shaft and a liquid-filled centrifugal pump, a ball plunger (5) and a sliding shoe (6) are rolled into a whole and are connected in a spherical hinge, the axis of the ball plunger (5) is vertical to the axis of the hollow composite shaft (8), the sliding shoe (6) is in contact fit with an eccentric disc (8 d) on the hollow composite shaft (8), and when the eccentric disc (8 d) rotates along with the hollow composite shaft (8), the ball plunger (5) and the sliding shoe (6) are driven to move in a corresponding plunger hole (10 c) formed in a pump body (10) and reset under the action of a reset spring (4); the digital switch oil absorption one-way valve (1) is an integrated body of the digital switch valve and the oil absorption one-way valve, the axis of the digital switch oil absorption one-way valve is overlapped with the axis of the plunger hole (10 c), and the oil discharge one-way valve (3) is arranged perpendicular to the digital switch oil absorption one-way valve (1); the digital switch oil suction one-way valve (1) and the oil discharge one-way valve (3) are combined in a pair and periodically and asynchronously open and close along with pressure change to form a high-low pressure cavity of the pump; the rotating speed sensor (17) and the position sensor (21) are arranged on the inner end cover (16), and probe parts of the rotating speed sensor and the position sensor are opposite to the magnetic steel of the motor rotor (15); the safety valve (2) is arranged in a threaded hole (7 d) on the front end cover (7), the inlet of the safety valve is communicated with the oil drain port (7 c), and the outlet of the safety valve is communicated with the safety valve oil return hole (1 (7 e); the pump body (10) and the front end cover (7) are positioned by a positioning pin (11), and a first O-shaped sealing ring (I), a second O-shaped sealing ring (II) and a third O-shaped sealing ring (III) are sealed and fixed on the shell (12) through screws.

2. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the hollow composite shaft (8) is provided with an inner flow passage (8 a), a slender micropore (8 b), a centrifugal tube (8 c) and an eccentric disc (8 d); the angles between the axes of the slender micropores (8 b) and the centrifuge tubes (8 c) and the axis of the hollow composite shaft (8) are respectively 60 degrees and 45 degrees, the slender micropores (8 b) are symmetrically arranged in two, and 6 centrifuge tubes (8 c) are uniformly distributed to form a liquid-filled centrifugal pump; the slender micropores (8 b) are communicated with the inner flow passage (8 a) and a gap between the lip-shaped sealing ring (25) and a second sealing ring (26), wherein the second sealing ring (26) is in labyrinth gap sealing.

3. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the digital switch oil absorption one-way valve (1) comprises: the valve comprises a valve body (1 a), a digital switch valve guide rod (1 b), a steel ball (1 c), a combined sealing ring (1 d), a spring (1 e), a spring seat (1 f), a combined sealing ring (1 g), a combined sealing gasket (1 i) and a digital switch valve body (1 j); the digital switch oil absorption one-way valve (1) is arranged in a threaded hole (10 b) on the pump body (10) through threads on the valve body (1 a), and the spring seat (1 f) encapsulates the spring (1 e) and the steel ball (1 c) in the valve body (1 a) through threads; the valve body (1 a) is provided with 4 to 6 radial holes (1 h) which are communicated with the annular cavity (10 e).

4. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the oil-suction ball-joint plunger piston is characterized in that 6 ball-joint plunger pistons (5) and 6 sliding shoes (6) are respectively uniformly distributed on an eccentric disc (8 d) and correspond to the digital switch oil-suction one-way valve (1) and the oil-discharge one-way valve (3) one by one, the sliding shoes (6) are of a bearing bush structure, oil holes (6 a) and oil grooves (6 b) are formed in the sliding shoes, and a ball head of the ball-joint plunger pistons (5) is opposite to the oil holes (6 a).

5. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the pump body (10) is a regular hexagonal prism, and is provided with a pumping oil hole (10 a), a digital switch oil suction one-way valve mounting threaded hole (10 b), a plunger hole (10 c), a rotor cavity (10 d), an annular cavity (10 e), an oil discharge one-way valve mounting hole (10 f), a safety valve oil return hole (2 g) and a through hole (10 h), wherein the pumping oil hole (10 a) is 6 waist-shaped gradually-contracted holes and is communicated with the annular cavity (10 e) one by one; the rotor cavity (10 d) is in a regular hexagonal prism shape, and 6 surfaces are respectively parallel to 6 surfaces of the pump body (10).

6. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the front end cover (7) is provided with a high-pressure oil collecting groove (7 a), a sliding bearing mounting hole (7 b), an oil discharge port (7 c), a safety valve mounting threaded hole (7 d) and a safety valve oil return hole (7 e), wherein the high-pressure oil collecting groove (7 a) is communicated with the oil discharge port (7 c) and outlets of 6 discharge one-way valves (3); the safety valve oil return hole 1 (7 e) is communicated with the pump oil pumping hole (10 a) through the safety valve oil return hole 2 (10 g) and the annular cavity (10 e).

7. The digital variable displacement hydraulic motor radial piston pump of claim 1, further comprising: the oil-cooled oil pump is characterized in that the shell (12) is provided with an oil inlet (12 a), rectangular flow channels (12 b), heat dissipation ribs (12 c) and a low-pressure oil collecting cavity (12 d), wherein the rectangular flow channels (12 b) are uniformly distributed in the axial direction from 4 to 6.