CN114876755B - Screw reciprocating single acting piston pump - Google Patents

Abstract

The spiral reciprocating type single-acting plunger pump comprises a pump body, wherein an end cover is arranged at the left end of the pump body, a cavity is formed between the end cover and the pump body, a main shaft capable of rotating around the axial line of the pump body and a plunger group capable of axially and reciprocally moving along the pump body are arranged in the cavity, and an oil inlet and an oil drain port are formed in the right side wall surface of the pump body; the cavity comprises a transmission cavity and a plurality of plunger cavities which are mutually communicated, the transmission cavity is positioned at the left part of the pump body, the plunger cavities are positioned at the right part of the pump body, and the plunger cavities are uniformly distributed along the circumferential direction of the pump body; the right end face of each plunger cavity is provided with an oil suction duct and an oil discharge duct; a main shaft is arranged in the transmission cavity, and a reciprocating thread groove is formed in the shaft section, which is positioned in the transmission cavity, on the main shaft; the plunger group comprises a claw-shaped frame and a plurality of plungers correspondingly arranged in plunger cavities, the plungers are arranged in the plunger cavities, and the plungers can do linear reciprocating motion along the axial direction of the pump body. The invention can obtain very high discharge pressure, has no relation with the flow rate and pressure, and has good suction performance and higher efficiency.

Description

Screw reciprocating single acting piston pump

Technical Field

The invention relates to the technical field of hydraulic pumps, in particular to a spiral reciprocating single-acting plunger pump.

Background technique

The hydraulic pump is the power element of the hydraulic system. It is driven by an engine or an electric motor, sucking oil from the hydraulic oil tank, forming a pressure oil discharge, and sending it to the actuator. Hydraulic pumps are divided into gear pumps, plunger pumps, vane pumps and screw pumps according to their structure. Their advantages and disadvantages are as follows:

Gear pump: small size, simple structure, no strict requirements on oil cleanliness, and cheap price; but the pump shaft is subject to unbalanced force, severe wear, and large leakage.

Vane pump: divided into double-acting vane pump and single-acting vane pump. This pump has uniform flow, stable operation, low noise, higher pressure and volume efficiency than gear pump, and more complex structure than gear pump.

Plunger pump: high volumetric efficiency, low leakage, can work under high pressure, mostly used in high-power hydraulic systems; but complex structure, high requirements for material and processing precision, expensive, and high requirements for oil cleanliness.

Screw pump: The speed is low, generally 20r/min~90r/min, with little mechanical wear and no cavitation. The flow channel is wide and can transport oil containing solids. The pump body structure is semi-open, so the operation inside the pump can be observed. However, it is large in size and occupies a large area. Due to the limitations of mechanical processing conditions, the pump shaft cannot be too long, so the head is low, generally not exceeding 10m.

A plunger pump is a type of pump in a hydraulic system that relies on the reciprocating motion of a plunger in the pump body to change the volume of a sealed working chamber to achieve oil suction and oil pressure. Traditional plunger pumps can be divided into three categories according to the arrangement of multiple plungers: axial piston pumps, radial piston pumps, and reciprocating piston pumps, all of which use the periodic change of volume in the working chamber to achieve the purpose of conveying the medium. After passing through the pump, the mechanical energy of the prime mover is directly converted into the pressure energy of the conveying medium. The flow rate of the pump depends only on the change value of the working chamber volume and the frequency of its changes per unit time, and in theory has nothing to do with the discharge pressure. Compared with other forms of hydraulic pumps, plunger pumps are easier to achieve high pressure and large flow on the basis of maintaining high volumetric efficiency, and are widely used in high-pressure and heavy-load occasions such as aerospace and engineering machinery.

However, the flow rate of the reciprocating piston pump is not very stable, and the flow rate is smaller than that of the axial piston pump of the same volume. At the same time, due to the large number of moving parts inside the traditional piston pump and the complex structure, the moment of inertia is large when moving at high speed, and due to the large number of sliding friction pairs in the pump body structure, the wear and heat of the parts will also increase, directly affecting the service life and durability. Due to the above shortcomings, the wider application of the piston pump is limited.

Summary of the invention

In order to overcome the above problems, the present invention provides a spiral reciprocating single-acting plunger pump.

The technical solution adopted by the present invention is: a spiral reciprocating single-acting plunger pump, comprising a pump body, an end cover is arranged at the left end of the pump body, a cavity is formed between the end cover and the pump body, a main shaft which can rotate around the axis of the pump body and a plunger group which can reciprocate along the axial direction of the pump body are arranged in the cavity, and an oil inlet and an oil outlet are opened on the right wall of the pump body;

The cavity body comprises a transmission cavity and a plurality of plunger cavities which are interconnected, wherein the transmission cavity is located at the left part of the pump body, the plurality of plunger cavities are located at the right part of the pump body, and the plurality of plunger cavities are evenly distributed along the circumference of the pump body; an oil suction passage and an oil discharge passage are arranged on the right end face of each plunger cavity, the plurality of oil suction passages are respectively connected with the annular oil suction passage arranged in the pump body, the annular oil suction passage is connected with the oil inlet, an oil inlet check valve is arranged in the oil inlet, and the oil inlet check valve only allows oil to enter the plunger cavity from outside the pump body; the plurality of oil discharge passages are respectively connected with the annular oil discharge passage arranged in the pump body, the annular oil discharge passage is connected with the oil discharge port, an oil discharge check valve is arranged in the oil discharge port, and the oil discharge check valve only allows oil to flow out of the pump body from the plunger cavity;

The transmission cavity is provided with a main shaft extending to the left side of the end cover along the axial centerline direction of the pump body, the left end of the main shaft is installed on the end cover through the first bearing, and the right end of the main shaft is installed on the right inner wall of the transmission cavity through the second bearing; the shaft section on the main shaft and located in the transmission cavity is provided with a reciprocating thread groove, the reciprocating thread groove includes two thread grooves with opposite rotation directions, the pitch and lead of the two thread grooves are the same, and the two thread grooves are butted end to end at both ends of the shaft section to form a closed reciprocating thread groove; the shaft section on the main shaft and located in the transmission cavity is sleeved with a plunger group;

The plunger group includes a claw-shaped frame and a plurality of plungers correspondingly arranged in the plunger cavity, the center of the claw-shaped frame is provided with a through hole for being sleeved on the main shaft, and a slider matching the reciprocating thread groove is provided in the through hole; a plurality of claw feet extending to the right along the axial direction of the pump body are provided on the outer side of the claw-shaped frame, and the right end of each claw foot is correspondingly connected to a plunger; the plunger is arranged in the plunger cavity, and the plunger can make a linear reciprocating motion along the axial direction of the pump body, and the right end surface of the plunger and the plunger cavity enclose a closed chamber; the volume of the chamber changes with the reciprocating motion of the plunger, and when the plunger moves from the leftmost end to the rightmost end, the volume of the chamber gradually decreases; on the contrary, when the plunger moves from the rightmost end to the leftmost end, the volume of the chamber gradually increases; when the main shaft rotates around the axis of the pump body, it drives the slider to make a linear reciprocating motion along the axial direction of the pump body, thereby driving the plunger to make a linear reciprocating motion along the axial direction of the pump body; the chamber with a gradually increasing volume absorbs oil, and the chamber with a gradually decreasing volume discharges oil.

Furthermore, the number of the plunger chambers and plungers is an odd number to reduce the pulsation of the output high-pressure oil.

Furthermore, the left end face of the pump body is provided with four pump body threaded holes evenly distributed along the circumferential direction, and the end cover is provided with four end cover threaded holes corresponding to the pump body threaded holes one by one. Screws are provided in the end cover threaded holes and the pump body threaded holes, and the screws fix the pump body and the end cover together.

The basic principle of the present invention is as follows: the reciprocating screw adopts a special thread groove design, which is two left-handed and right-handed thread grooves, the pitch and lead of the two thread grooves are the same, and the two threads are butted end to end at the two ends of the screw to form a closed thread groove. The stroke and size of the slider are matched with the thread groove, and the two ends of the spiral screw are rigidly connected to the end cover and the pump body through bearings. When the spiral screw is driven by a motor to rotate continuously, the slider moves from one end of the thread groove to the other end along the groove, and moves back through the thread groove with the closed end, so as to realize the continuous reciprocating motion of the slider without changing the rotation direction of the screw. A reciprocating thread groove with a length matching the plunger stroke is machined at a suitable position of the main shaft of the spiral reciprocating plunger pump. The slider is rigidly connected to the plunger group, and the plunger and the plunger cavity are matched to form a closed cavity. The main shaft and the motor output shaft are connected by a coupling, and the main shaft is driven to rotate continuously by the motor. Driven by the main shaft, the slider reciprocates from one end to the other along the reciprocating thread groove, and drives the rigidly connected plunger group to reciprocate together, thereby realizing the change of the volume of the pump chamber. When the volume of the pump chamber increases, the pressure in the chamber decreases, and under the action of atmospheric pressure, the hydraulic oil enters the pump chamber from the oil cylinder through the oil inlet check valve to achieve oil suction; when the volume of the pump chamber decreases, the pressure in the chamber increases, and the hydraulic oil is discharged from the pump chamber through the oil discharge check valve. The slider completes one suction and discharge of oil when it reciprocates in the reciprocating thread groove once.

The beneficial effects of the present invention are:

1. It can obtain very high exhaust pressure, and the flow rate is independent of pressure, with good suction performance and high efficiency;

2. In principle, any medium can be transported, almost without being restricted by the physical or chemical properties of the medium;

3. Reduce the friction pairs of the traditional axial piston pump's slipper and swash plate, and improve the service life and durability of the pump;

4. The reciprocating screw (reciprocating thread groove) has reliable reversing, long service life and low manufacturing cost;

5. Simple structure and low cost. Compared with other reciprocating piston pumps, the solution provided by the present invention has fewer parts and components, and is easier to process and assemble, with low manufacturing cost, which is conducive to practical industrial application and large-scale batch production.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is a schematic diagram of the assembly of the present invention;

FIG3 is a schematic structural diagram of a main shaft of the present invention;

FIG4 is a schematic structural diagram of a pump body of the present invention;

FIG5 is a schematic diagram of the structure of the oil discharge passage in the pump body of the present invention;

FIG6 is a schematic diagram of the structure of the plunger assembly of the present invention;

FIG7 is a schematic structural diagram of the left end cover of the present invention;

Explanation of the accompanying drawings: 1 is the main shaft, 2 is the end cover, 3 is the screw, 4 is the pump body, 5 is the plunger group, 6 is the bearing, 7 is the oil discharge check valve, 8 is the oil inlet check valve, 9 is the reciprocating thread groove, 10 is the pump body threaded hole, 11 is the pump body bearing hole, 12 is the plunger cavity, 13 is the oil discharge channel, 14 is the annular oil discharge channel, 15 is the oil discharge port, 16 is the slider, 17 is the end cover threaded hole, and 18 is the end cover bearing hole.

Detailed ways

The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Referring to the accompanying drawings, a spiral reciprocating single-acting plunger pump includes a pump body 4, the left end of the pump body 4 is provided with an end cover 2, the left end face of the pump body 4 is provided with four pump body threaded holes 10 evenly distributed along the circumferential direction, the end cover 2 is provided with four end cover threaded holes 17 corresponding to the pump body threaded holes 10 one by one, and screws 3 are provided in the end cover threaded holes 17 and the pump body threaded holes 10, and the screws 3 fix the pump body 4 and the end cover 2 together.

A cavity is formed between the end cover 2 and the pump body 4, in which a main shaft 1 that can rotate around the axis of the pump body 4 and a plunger group 5 that can reciprocate along the axial direction of the pump body 4 are arranged. The right wall of the pump body 4 is provided with an oil inlet and an oil outlet 15;

The cavity body includes a transmission cavity and a plurality of plunger cavities 12 that are interconnected, wherein the transmission cavity is located at the left part of the pump body 4, the plurality of plunger cavities 12 are located at the right part of the pump body 4, and the plurality of plunger cavities 12 are evenly distributed along the circumference of the pump body 4; an oil suction passage and an oil discharge passage are provided on the right end face of each plunger cavity, the plurality of oil suction passages are respectively communicated with the annular oil suction passages provided in the pump body 4, the annular oil suction passages are communicated with the oil inlet, an oil inlet check valve is provided in the oil inlet, and the oil inlet check valve only allows oil to enter the plunger cavity from outside the pump body 4; the plurality of oil discharge passages are respectively communicated with the annular oil discharge passages provided in the pump body 4, the annular oil discharge passages are communicated with the oil discharge port 15, an oil discharge check valve is provided in the oil discharge port 15, and the oil discharge check valve only allows oil to flow out of the plunger cavity from the pump body 4;

The transmission cavity is provided with a main shaft 1 extending along the axis direction of the pump body 4 to the left side of the end cover 2, the left end of the main shaft 1 is installed on the end cover 2 through the first bearing, and the right end of the main shaft 1 is installed on the right inner wall of the transmission cavity through the second bearing; the first bearing is installed on the end cover bearing hole 18 on the right side of the end cover 2, and the second bearing is installed on the pump body bearing hole 11 on the right wall of the transmission cavity; the shaft section on the main shaft 1 and located in the transmission cavity is provided with a reciprocating thread groove 9, the reciprocating thread groove 9 includes two thread grooves with opposite rotation directions, the pitch and lead of the two thread grooves are the same, and the two threads are butted end to end at both ends of the shaft section to form a closed reciprocating thread groove 9; the shaft section on the main shaft 1 and located in the transmission cavity is sleeved with a plunger group 5;

The plunger group 5 includes a claw-shaped frame and a plurality of plungers correspondingly arranged in the plunger cavity. The center of the claw-shaped frame is provided with a through hole for sleeved on the main shaft 1. The size of the through hole matches the diameter of the shaft section of the main shaft 1 with the reciprocating thread groove 9. A slider 16 that cooperates with the reciprocating thread groove 9 is rigidly connected in the hole; the outer side of the claw-shaped frame is provided with a plurality of claw feet extending to the right along the axial direction of the pump body 4, and the right end of each claw foot is correspondingly connected to a plunger; the plunger is arranged in the plunger cavity 12, and the plunger can make a linear reciprocating motion along the axial direction of the pump body 4 The right end face of the plunger and the plunger cavity 12 enclose a closed chamber; the volume of the chamber changes with the reciprocating motion of the plunger. When the plunger moves from the leftmost end to the rightmost end, the volume of the chamber gradually decreases; on the contrary, when the plunger moves from the rightmost end to the leftmost end, the volume of the chamber gradually increases; when the main shaft 1 rotates around the axis of the pump body 4, it drives the slider 16 to make a linear reciprocating motion along the axial direction of the pump body 4, thereby driving the plunger to make a linear reciprocating motion along the axial direction of the pump body 4; the chamber with a gradually increasing volume absorbs oil, and the chamber with a gradually decreasing volume discharges oil.

In some embodiments of the present invention, the number of plungers in the plunger cavity and the plunger group is an odd number, such as 7, 9, 11, etc., which can reduce the pulsation of the output high-pressure oil.

By increasing or decreasing the number of plunger cavities and plunger groups, thereby changing the volume of the pump cavity, the displacement of the plunger pump can be increased or decreased. Changing the size of the plunger can also change the displacement of the plunger pump.

By adjusting the length of the reciprocating thread groove on the spindle, the stroke of the slider along the axial direction of the spindle can be adjusted, and the stroke of the plunger group rigidly connected to the slider also changes accordingly. In this way, the displacement of the output oil can be adjusted.

When the length of the thread groove remains unchanged, that is, the stroke of the plunger group remains unchanged, changing the pitch of the reciprocating thread groove within an appropriate range can change the movement speed of the slider in the thread groove, that is, the reciprocating motion rate of the plunger group, while keeping the spindle speed unchanged, thereby changing the action speed and output flow rate of the reciprocating plunger pump.

The above plunger pump is a single-acting reciprocating thread groove plunger pump. In other embodiments of the present invention, it can be converted into a double-acting pump by machining two sections of reciprocating threads on the main shaft, installing two sets of plunger assemblies, and cooperating with two sets of pump chambers.

The working principle of this spiral reciprocating single-acting plunger pump is as follows:

When the main shaft 1 rotates continuously under the drive of the motor, the slider 16 fixed to the plunger group 5 reciprocates along the reciprocating thread groove 9 under the action of friction, thereby driving each plunger to reciprocate in the plunger cavity 12, forming a volume change. When the plunger moves out of the plunger cavity 12, the volume of the pump cavity increases, the pressure in the cavity decreases, and under the action of atmospheric pressure, the oil enters the plunger cavity 12 from the oil cylinder through the oil suction oil channel and the oil inlet check valve 8; when the plunger moves into the plunger cavity 12, the volume of the pump cavity decreases, the pressure in the cavity increases, and the oil flows out of the plunger cavity 12 through the oil discharge oil channel 13 and the oil discharge check valve 7. The slider 16 reciprocates once in the reciprocating thread groove 9 to complete one suction and discharge of oil.

The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims (1)

1. Spiral reciprocating type single-acting plunger pump, its characterized in that: the novel hydraulic pump comprises a pump body (4), wherein an end cover (2) is arranged at the left end of the pump body (4), a cavity is formed between the end cover (2) and the pump body (4), a main shaft (1) capable of rotating around the axial line of the pump body (4) and a plunger group (5) capable of axially and reciprocally moving along the pump body (4) are arranged in the cavity, and an oil inlet and an oil drain port (15) are formed in the right side wall surface of the pump body (4);

The cavity comprises a transmission cavity and a plurality of plunger cavities which are mutually communicated, wherein the transmission cavity is positioned at the left part of the pump body (4), the plunger cavities are positioned at the right part of the pump body (4), and the plunger cavities are uniformly distributed along the circumferential direction of the pump body (4); the right end face of each plunger cavity is provided with an oil suction channel and an oil discharge channel, the plurality of oil suction channels are respectively communicated with an annular oil suction channel arranged in the pump body (4), the annular oil suction channel is communicated with an oil inlet, an oil inlet one-way valve is arranged in the oil inlet, and the oil inlet one-way valve only allows oil to enter the plunger cavity from the outside of the pump body (4); the oil discharge channels are respectively communicated with an annular oil discharge channel arranged in the pump body (4), the annular oil discharge channel is communicated with an oil discharge port (15), an oil discharge one-way valve is arranged in the oil discharge port (15), and the oil discharge one-way valve only allows oil to flow out of the pump body (4) from the plunger cavity;

The transmission cavity is internally provided with a main shaft (1) extending to the left side of the end cover (2) along the axial line direction of the pump body (4), the left end of the main shaft (1) is installed on the end cover (2) in a penetrating way through a first bearing, and the right end of the main shaft (1) is installed on the inner wall of the right side of the transmission cavity through a second bearing; the spindle (1) is provided with a reciprocating thread groove (9) at the shaft section positioned in the transmission cavity, the reciprocating thread groove (9) comprises two thread grooves with opposite rotation directions, the pitch and the lead of the two thread grooves are the same, and the two thread grooves are in head-to-tail butt joint at the two ends of the shaft section to form a closed reciprocating thread groove (9); a plunger group (5) is sleeved on the spindle (1) and on the shaft section positioned in the transmission cavity;

The plunger group (5) comprises a claw-shaped frame and a plurality of plungers correspondingly arranged in plunger cavities, a through hole used for being sleeved on the main shaft (1) is arranged in the center of the claw-shaped frame, and a sliding block (16) matched with the reciprocating thread groove (9) is arranged in the through hole; the outer side of the claw-shaped frame is provided with a plurality of claw feet extending rightwards along the axial direction of the pump body (4), and the right end of each claw foot is correspondingly connected with a plunger; the plunger is arranged in the plunger cavity, and can do linear reciprocating motion along the axial direction of the pump body (4), and the right end surface of the plunger and the plunger cavity enclose a closed cavity; the volume of the cavity changes along with the reciprocating motion of the plunger, and when the plunger moves from the leftmost end to the rightmost end, the volume of the cavity gradually becomes smaller; conversely, as the plunger moves from the rightmost end to the leftmost end, the chamber volume becomes progressively larger; when the main shaft (1) rotates around the axial line of the pump body (4), the sliding block (16) is driven to do linear reciprocating motion along the axial direction of the pump body (4), so that the plunger is driven to do linear reciprocating motion along the axial direction of the pump body (4); the chamber with gradually increased volume absorbs oil, and the chamber with gradually reduced volume discharges oil;

the number of the plunger cavities and the plungers is odd number, so that the pulsatility of the output high-pressure oil is reduced;

The left end face of the pump body (4) is provided with four pump body threaded holes (10) uniformly distributed along the circumferential direction, the end cover (2) is provided with four end cover threaded holes (17) corresponding to the pump body threaded holes (10) one by one, the end cover threaded holes (17) and the pump body threaded holes (10) are internally provided with screws (3), and the screws (3) are used for fixedly connecting the pump body (4) with the end cover (2).