CN114439717A - Parallel double-plunger double-variable servo pump - Google Patents

Abstract

A parallel double-plunger double-variable servo pump comprises a front shell component and a rear shell component which are coaxially connected, wherein a pump variable component is arranged in the front shell component, and a transmission component and a pumping component are arranged in the rear shell component; the transmission assembly comprises an internal gear, a driving wheel and a driven wheel, wherein the driving wheel and the driven wheel are meshed with the internal gear, and the torque input by the driving motor is symmetrically output through the internal gear. The front end of a plunger of the pumping assembly penetrates through a driven wheel of the transmission assembly and extends into the parallel cylinder body of the pump variable assembly to form a closed cavity, the rear end of the plunger is connected with the space cam-cone roller mechanism, and the front cam and the rear cam rotate and are constrained by the cone roller to realize axial movement. The inertia moment is very small when the cylinder body swings and changes the variable, so the variable response is faster; meanwhile, the required driving force of the cylinder body swing variable is small, the cylinder body swing variable can be driven through a micro stepping motor and a speed reducer, and the variable mechanism is very small.

Description

Parallel double-plunger double-variable servo pump

Technical Field

The invention relates to the field of fluid transmission and control, in particular to a parallel double-plunger double-variable servo pump.

Background

In operation, the swash plate axial piston pump is rotated by the prime mover through the drive shaft to drive the cylinder block. The plunger installed in the cylinder body can realize reciprocating motion under the constraint of the swash plate, so that the closed volume at the bottom of the plunger is periodically changed. The plunger pump absorbs and discharges oil through an oil distribution window of the oil distribution disc. Meanwhile, the plunger pump can adjust the single reciprocating displacement of the plunger by changing the included angle between the swash plate and the main shaft, so that variable displacement output within a certain range is realized.

The traditional swash plate type axial plunger variable displacement pump has a complex internal structure, the swash plate structure of the traditional swash plate type axial plunger variable displacement pump has overturning force in the working process, and the stability of a pump body is poor when the pump body runs at high speed; three pairs of main sliding friction pairs exist in the pump body structure, parts are easy to wear in the operation process, the heat productivity is large, and the service life and the durability of the pump are influenced; meanwhile, because the volume of the plunger is periodically changed in the movement process, the instantaneous flow also periodically changes along with the rotation of the cylinder body, and the stable output of oil is not facilitated.

Patent document CN205895515U proposes a hydraulic pump with a novel structure, which uses the principle of plunger two-degree-of-freedom motion to realize the oil suction and discharge function, and is named as a two-dimensional (2D) plunger pump because it has two-dimensional motion during operation. The application of the two-degree-of-freedom motion principle enables the hydraulic pump to form a novel flow distribution mode, and has the advantages of novel and compact structure, small size, light weight, high discharge capacity and high volumetric efficiency.

Disclosure of Invention

In order to overcome the defects that the traditional swash plate type axial plunger variable displacement pump is slow in pressure building, has overturning moment, is difficult to realize servo control and the like, the invention provides a parallel double-plunger double-variable servo pump.

The technical scheme adopted by the invention is as follows: a parallel double-plunger double-variable servo pump comprises a front shell assembly and a rear shell assembly which are coaxially connected, wherein a pump variable assembly is arranged in the front shell assembly, and a transmission assembly and a pumping assembly are arranged in the rear shell assembly;

the rear shell assembly comprises a rear shell, a rear shell end cover and a driving motor, wherein the driving motor is arranged at the upper part of the rear side of the rear shell, two space cam-cone roller installation cavities which protrude backwards are arranged at the lower part of the rear side of the rear shell, and the two space cam-cone roller installation cavities are axially symmetrical; a rear shell end cover is arranged at the opening at the rear end of the space cam-cone roller mounting cavity, and a first mandrel is arranged at the center of the front end face of the rear shell end cover; a gear speed regulation disc is embedded in the front end face of the rear shell and comprises a copper ring, a front baffle and a rear baffle, wherein the front baffle and the rear baffle are arranged on the front side and the rear side of the copper ring;

the transmission assembly is arranged in the transmission assembly mounting cavity and comprises an annular internal gear, a driving wheel and driven wheels, the upper part of the inner side of the internal gear is internally meshed with the driving wheel, the two driven wheels are symmetrically arranged at the lower part of the inner side of the internal gear, and the two driven wheels are internally meshed with the internal gear; a motor shaft of the driving motor penetrates through the rear shell and the first piston framework oil seal to be connected with a driving wheel, and the driving wheel transmits power to two driven wheels which are symmetrically arranged below the driving wheel;

the pumping assembly comprises a space cam-cone roller mechanism and a plunger, and the space cam-cone roller mechanism is arranged in a space cam-cone roller mounting cavity; the space cam-cone roller mechanism comprises a rear cam, two groups of cone rollers, a front cam and a transmission sliding pin, wherein each group of cone rollers comprises a pair of mutually vertical cone rollers; two groups of conical rollers are fixed in the space cam-conical roller mounting cavity in a staggered manner, and the axes of the two groups of conical rollers are mutually vertical but do not intersect; the two groups of conical rollers are respectively in contact fit with the end surfaces of the front cam and the rear cam, the end surfaces of the front cam and the rear cam are deceleration curved surfaces with equal acceleration and the like, and the deceleration curved surfaces with equal acceleration and the like have axial fluctuation; the highest point of the front cam corresponds to the highest point of the rear cam, and the lowest point of the front cam corresponds to the lowest point of the rear cam;

the cam hub of the front cam is inserted into the gear hub hole of the driven wheel, the gear hub hole and the outer cylindrical surface of the front cam hub are respectively provided with a half pin hole, a transmission sliding pin arranged axially is inserted into the pin holes, and the transmission sliding pin connects the driven wheel and the front cam, so that the driven wheel and the front cam can rotate together and can move axially and relatively; the front cam is fixedly connected with the rear cam and the plunger through a long transmission pin and an end transmission pin in the radial direction, and the first mandrel is inserted into a central hole of the rear cam; the front end of the plunger penetrates through the driven wheel through a first linear bearing along the axial direction, and the first linear bearing is fixed in the driven wheel; the front cam and the rear cam are constrained by the cone roller to realize axial movement while rotating;

the front shell assembly comprises a front shell and a controller cover, the controller cover is arranged on the upper portion of the front end of the front shell, and the controller assembly is arranged in the controller cover; the lower part of the front end of the front shell is provided with two cylinder body installation cavities protruding forwards and a worm and gear installation cavity, and the worm and gear installation cavity is positioned below the cylinder body installation cavity; the cylinder body mounting cavity is provided with a high-pressure oil port, a low-pressure oil port and an oil unloading port, the inner wall of the cylinder body mounting cavity is provided with a circular high-pressure oil duct and a circular low-pressure oil duct, the high-pressure oil duct is communicated with the high-pressure oil port, and the low-pressure oil duct is communicated with the low-pressure oil port; a front shell end cover is arranged at an opening at the front end of the cylinder body mounting cavity, and a second mandrel is arranged in the center of the rear end of the front shell end cover;

the pump variable component comprises two parallel cylinder bodies and a worm gear transmission mechanism, the parallel cylinder bodies are arranged in the cylinder body mounting cavities, and the axes of the parallel cylinder bodies are superposed with the axes of the front mandrel of the front shell end cover, the plunger, the front cam, the rear cam and the rear mandrel of the rear shell end cover; a closed cavity is formed among the second mandrel, the parallel cylinder body and the plunger, the volume of the closed cavity changes along with the axial movement of the plunger, the volume is gradually increased when the plunger moves from the foremost end to the rearmost end, and conversely, the volume is gradually reduced when the plunger moves from the rearmost end to the foremost end;

two groups of flow distribution windows are axially arranged on the parallel cylinder body, and the positions of the two groups of flow distribution windows respectively correspond to the high-pressure oil duct and the low-pressure oil duct; each group of flow distribution windows comprises two flow distribution windows which are vertical to each other, and the two groups of oil distribution windows are arranged in a staggered manner; the left side, the middle and the right side of the two groups of flow distribution windows are respectively provided with a cylinder body sealing ring for keeping the inlet oil and the outlet oil isolated from each other; a plunger through groove is formed in the plunger, a plunger through groove communicated with the plunger through groove is formed in the left end face of the plunger, and the plunger is communicated with the two groups of flow distribution windows through the plunger through grooves; the closed cavity absorbs oil when the volume is increased and discharges oil when the volume is reduced;

the worm and gear transmission mechanism is arranged in the worm and gear installation cavity and comprises a stepping motor and a worm; a step motor and a worm end cover are respectively arranged at two ends of the worm and gear installation cavity, which are vertical to the parallel cylinder body, and a motor shaft of the step motor is vertical to the parallel cylinder body and is connected with the worm through a coupler; a worm gear and gear assembly matched with the worm is arranged on the stepped shaft, and the worm gear and gear assembly is sequentially provided with a worm gear end and a gear section along the axial direction; the stepped shaft is perpendicular to the worm, one end of the stepped shaft is fixed in a stepped hole of the front shell, and the other end of the stepped shaft penetrates through the transmission assembly and is fixed in a shaft hole in the front end face of the rear shell;

the rear ends of the two parallel cylinder bodies are respectively provided with a pump variable gear, the worm wheel section of the worm wheel gear combination body is meshed with the worm, and the gear section of the worm wheel gear combination body is meshed with the pump variable gear; the stepping motor drives the wheel worm to rotate, so that the parallel cylinder bodies are driven to rotate, and the displacement of the servo pump is adjustable.

Further, a front shell sealing ring is arranged between the front shell end cover and the front shell, and a front mandrel sealing ring is sleeved on the front mandrel so as to realize the sealing between the front shell and the parallel cylinder body.

Furthermore, a conical roller shaft hole is formed in the space cam-conical roller mounting cavity at a position corresponding to the conical roller; an intermediate shaft hole is communicated between two conical roller shaft holes which are close to each other on the two space cam-conical roller mounting cavities, an intermediate shaft is inserted into the intermediate shaft hole, and a long claw point slotted set screw is mounted in a set screw hole in the middle section of the intermediate shaft hole for setting; the conical roller shaft is inserted into the conical roller shaft holes at other positions from the outer side, the conical roller shaft sequentially penetrates through the conical roller retainer ring and the sealing ring to be fixed with the conical roller, and the top of the conical roller shaft is provided with an inner hexagonal flat end screw which fixes the conical roller shaft in the conical roller shaft hole.

Further, a thrust bearing is arranged at the front end of the parallel cylinder body, and the thrust bearing consists of a thrust needle roller, a retainer and a thrust washer; the outer edge of the rear end of the parallel cylinder body is provided with a rear sealing ring, and the inner edge of the rear end of the cylinder body is provided with a second piston framework oil seal; the rear end of the cylinder body is fixed with the pump variable gear through a gear transmission pin; the plunger penetrates through the second variable gear of the pump and the oil seal of the piston framework to extend into the parallel cylinder body.

The invention has the beneficial effects that:

(1) the driving motor drives the cam-cone roller mechanism to rotate through the transmission assembly, and two-dimensional movement of the plunger is achieved. And a driving wheel, an internal gear and a driven wheel in the transmission assembly realize the symmetrical output of driving power. The parallel cylinder body drives the gear fixed on the parallel cylinder body to rotate through the worm gear and worm transmission mechanism, so that the position of a window of the cylinder body is changed, and the variable is finished. When the plunger through groove is communicated with the cylinder body window, the variable displacement pump sucks and discharges oil.

(2) The separation of the transmission function and the pumping function of the pump body is realized. An elaborate parallel structure and a novel pump variable mechanism are adopted. The power is symmetrically output to the pumping mechanism through the transmission system formed by the internal gear and the external gear, and flow pulsation is reduced through the parallel cam-cone roller transmission mechanism of the pumping mechanism. The inertia moment is very small when the cylinder body swings to change the variable, so that the variable response is faster; meanwhile, the required driving force of the cylinder body swing variable is small, the cylinder body swing variable can be driven through a micro stepping motor and a speed reducer, and the variable mechanism is very small.

Drawings

Fig. 1 is an exploded view of the present invention.

Fig. 2 is an exploded view of the rear housing assembly of the present invention.

Figure 3 is an exploded view of the pumping assembly of the present invention.

Fig. 4 is an exploded view of the drive assembly of the present invention.

Fig. 5 is an exploded view of the pump variable assembly of the present invention.

Fig. 6 is an exploded view of the front housing assembly of the present invention.

Description of reference numerals: 1. a rear housing assembly; 101. a rear housing; 102. a rear housing end cap; 103. a pump motor; 2. a pumping assembly; 211. a rear cam; 212. a linear bearing; 221 a conical roller; 222. a conical roller retainer ring; 223. a cone roller shaft; 224. a seal ring; 225. a hexagon socket flat end screw; 231. a conical roller; 232. a conical roller retainer ring; 233. a conical roller intermediate shaft; 234. a long claw point is provided with a slot and a set screw; 241. a front cam; 242. a long drive pin; 243. a short drive pin; 251. a plunger; 252. a first linear bearing; 253. a drive slide pin; 3. a drive assembly; 31. a tailgate; 32. a piston framework oil seal; 33. a driven wheel; 34. an internal gear; 35. a driving wheel; 36. a copper ring; 37. a front baffle; 4. a pump variable component; 401. a thrust needle roller and a retainer; 402. a thrust washer; 403. the cylinders are connected in parallel; 404. a cylinder body sealing ring; 405. a seal ring; 406. a second piston skeleton oil seal; 407. a pump variable gear; 408. a gear drive pin; 409. a circlip for a hole; 410. a needle bearing; 411. a worm gear assembly; 412. a stepped shaft; 413. a needle bearing; 414. a needle bearing; 415. a stepping motor; 416. a coupling; 417. a circlip for a hole; 418. a seal ring; 419. a seal ring; 420. a needle bearing; 421. a seal ring; 422. a worm; 423. a thrust ball bearing; 424. a needle bearing; 425. a retainer ring; 426. a thrust ball bearing; 427. a worm end cap seal ring; 428. a worm gear end cover; 5. a front housing component; 501. a front housing; 502. a seal ring; 503. a controller cover; 504. a seal ring; 505. a seal ring; 506. a front housing end cap.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments, but not all embodiments, of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the orientations or positional relationships indicated as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., appear based on the orientations or positional relationships shown in the drawings only for the convenience of describing the present invention and simplifying the description, but not for indicating or implying that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the appearances of the terms "first," "second," and "third" are only used for descriptive purposes and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to the attached drawings, the parallel double-plunger double-variable servo pump comprises a front shell assembly 5 and a rear shell assembly 1 which are coaxially connected, wherein a pump variable assembly 4 is arranged in the front shell assembly 5, and a transmission assembly 3 and a pumping assembly 2 are arranged in the rear shell assembly 1;

the rear shell assembly 1 comprises a rear shell 101, a rear shell end cover 102 and a driving motor 103, wherein the driving motor 103 is arranged at the upper part of the rear side of the rear shell 101, two space cam-cone roller installation cavities which protrude backwards are arranged at the lower part of the rear side of the rear shell 101, and the two space cam-cone roller installation cavities are axisymmetric; a rear shell end cover 102 is arranged at an opening at the rear end of the space cam-cone roller mounting cavity, and a first mandrel is arranged in the center of the front end face of the rear shell end cover 102; a gear speed regulation disc is embedded on the front end face of the rear shell 101 and comprises a copper ring 36, a front baffle 37 and a rear baffle 31 which are arranged on the front side and the rear side of the copper ring 36, and the copper ring 36, the front baffle 37 and the rear baffle 31 enclose a transmission assembly installation cavity;

the transmission assembly 3 is arranged in the transmission assembly mounting cavity, the transmission assembly 3 comprises a circular ring-shaped internal gear 34, a driving wheel 35 and driven wheels 33, the upper part of the inner side of the internal gear 34 is internally meshed with the driving wheel 35, the two driven wheels 33 are symmetrically arranged at the lower part of the inner side of the internal gear 34, and the two driven wheels 33 are internally meshed with the internal gear 34; the motor shaft of the driving motor 103 passes through the rear shell 101 and the first piston framework oil seal 32 to be connected with the driving wheel 34, and the driving wheel 34 transmits power to the two driven wheels 33 which are symmetrically arranged below, so that the power is symmetrically output.

The pumping mechanisms are symmetrically arranged and therefore only one side mechanism will be characterized in the following description.

The pumping assembly 2 comprises a space cam-cone roller mechanism and a plunger fixed on the space cam-cone roller mechanism, and the space cam-cone roller mechanism is arranged in a space cam-cone roller mounting cavity; the space cam-cone roller mechanism comprises a rear cam 211, two groups of cone rollers 221, a front cam 241 and a transmission sliding pin 253, wherein each group of cone rollers 221 comprises a pair of mutually vertical cone rollers 221; the two groups of conical rollers 221 are fixed in the space cam-conical roller mounting cavity in a staggered manner, and the axes of the two groups of conical rollers 221 are mutually vertical but do not intersect;

a conical roller shaft hole is formed in the space cam-conical roller mounting cavity at a position corresponding to the conical roller 221; an intermediate shaft hole is communicated between two conical roller shaft holes which are close to each other on the two space cam-conical roller mounting cavities, an intermediate shaft 233 is inserted into the intermediate shaft hole, and a long claw tip slotted fastening screw 234 is mounted in a fastening screw hole at the middle section of the intermediate shaft hole for fastening; the cone roller shaft 233 is inserted into the cone roller shaft holes at other positions from the outer side, the cone roller shaft 233 sequentially penetrates through the cone roller retainer ring and the sealing ring to be fixed with the cone roller, the top of the cone roller shaft 223 is provided with an inner hexagonal flat end screw 225, and the cone roller shaft 223 is fixed in the cone roller shaft hole by the inner hexagonal flat end screw 225.

The two groups of conical rollers 221 are in line contact with the end surfaces of the front cam 241 and the rear cam 211 respectively, the end surfaces of the front cam 241 and the rear cam 211 are deceleration curved surfaces with equal acceleration and the like, the deceleration curved surfaces with equal acceleration and the like have axial fluctuation, and the deceleration curved surfaces with equal acceleration and the like comprise two highest points and two lowest points; the highest point of the front cam 241 corresponds to the highest point of the rear cam 211, and the lowest point of the front cam 241 corresponds to the lowest point of the rear cam 211;

the front cam 241, the driven wheel 33 in the transmission mechanism 3 and four transmission sliding pins 253 form a sliding pin coupling, a cam hub of the front cam 241 is inserted into a gear hub hole of the driven wheel 33, the gear hub hole and the outer cylindrical surface of the cam hub of the front cam 241 are respectively provided with a half pin hole, the transmission sliding pin 253 arranged axially is inserted into the pin hole, and the transmission sliding pin 253 connects the driven wheel 33 and the front cam 241, so that the driven wheel 33 and the front cam 241 can do axial relative movement while rotating together; the front cam 241 is fixedly connected with the rear cam 211 and the plunger 251 through a long driving pin 242 and an end driving pin 243 in the radial direction, and the first mandrel is inserted into a central hole of the rear cam 211; the front end of the plunger 251 penetrates through the driven wheel 33 along the axial direction through a first linear bearing 252, and the first linear bearing 252 is fixed in the driven wheel 33 and only moves relative to the plunger in the axial direction; the front cam 241 and the rear cam 211 are constrained by the cone roller 221 to realize axial movement while rotating;

when the cam-cone roller mechanism and the plunger rotate and reciprocate, a dynamic and static pressure sliding support structure is adopted, one end of the dynamic and static pressure sliding support structure is formed by the plunger and an inner hole of the parallel cylinder body, and the other end of the dynamic pressure sliding support structure is formed by a first mandrel of the end cover of the rear shell and a hub hole of the cam.

The front housing assembly 5 comprises a front housing 501 and a controller cover 503, wherein the controller cover 503 is arranged at the upper part of the front end of the front housing 501, and the controller cover 503 is used for placing the controller assembly; the lower part of the front end of the front shell 501 is provided with two cylinder body installation cavities protruding forwards and a worm and gear installation cavity, and the worm and gear installation cavity is positioned below the cylinder body installation cavity; the cylinder body installation cavity is provided with a high-pressure oil port, a low-pressure oil port and an oil unloading port, the two outer side surfaces of the left pump body 501 are provided with three holes, wherein the low-pressure oil port is closest to the left end surface, the high-pressure oil port is in the middle, the oil unloading port is closest to the right side, and the pressure relief function is realized; the inner wall of the cylinder body mounting cavity is provided with a circular high-pressure oil duct and a circular low-pressure oil duct, the high-pressure oil duct is communicated with a high-pressure oil port, and the low-pressure oil duct is communicated with a low-pressure oil port; a front shell end cover 506 is arranged at an opening at the front end of the cylinder body mounting cavity, and a second mandrel is arranged at the center of the rear end of the front shell end cover 506; a front housing end cover 506 is fixed with the rear housing assembly through bolts, a front housing sealing ring 505 is arranged between the front housing end cover 506 and the front housing 501, and a front spindle sealing ring 504 is sleeved on the front spindle to realize sealing between the front housing 501 and the parallel cylinder body 403.

The pump variable component 4 comprises two parallel cylinder bodies 403 and a worm gear transmission mechanism, wherein the parallel cylinder bodies 403 are arranged in cylinder body mounting cavities, and the axes of the parallel cylinder bodies 403 are superposed with the axes of a front spindle of the front shell end cover 506, a plunger 251, a front cam 211, a rear cam 241 and a rear spindle of the rear shell end cover 102; a closed cavity is formed among the second mandrel, the parallel cylinder body 403 and the plunger 251, the volume of the closed cavity changes along with the axial movement of the plunger 251, the volume is gradually increased when the plunger 251 moves from the foremost end to the rearmost end, and conversely, the volume is gradually reduced when the plunger 251 moves from the rearmost end to the foremost end;

two groups of flow distribution windows are axially arranged on the parallel cylinder body 403, and the positions of the two groups of flow distribution windows respectively correspond to the high-pressure oil duct and the low-pressure oil duct; each group of flow distribution windows comprises two flow distribution windows which are vertical to each other, and the two groups of oil distribution windows are arranged in a staggered manner; the left side, the middle side and the right side of the two groups of flow distribution windows are respectively provided with a cylinder body sealing ring 404 for keeping the inlet oil and the outlet oil isolated from each other; a plunger through groove is formed in a plunger rod of the plunger 251, a plunger through groove communicated with the plunger through groove is formed in the left end face of the plunger 251, and the plunger 251 is respectively communicated with the two groups of flow distribution windows through the plunger through groove; the closed cavity absorbs oil when the volume is increased and discharges oil when the volume is reduced;

the worm and gear transmission mechanism is arranged in the worm and gear installation cavity and comprises a stepping motor 415 and a worm 422; the two ends of the worm and worm wheel mounting cavity, which are perpendicular to the parallel cylinder body 403, are respectively provided with a stepping motor 415 and a worm end cover 428, and the worm end cover 428 is sealed by a worm end cover sealing ring 427; a motor shaft of the stepping motor 415 is vertical to the parallel cylinder 403, and the motor shaft of the stepping motor 415 is connected with the worm 422 through the coupler 416;

the worm 422 is supported by a needle bearing 424, and thrust ball bearings 423 and 426 positioned on shaft shoulders are respectively arranged at two ends of the needle bearing 424, wherein the thrust ball bearing 426 is nested with a retainer ring 425. A sealing ring 418 is arranged between the needle bearing 413 and the coupler and is sealed with a hole elastic retaining ring 417, and sealing rings 419 and 421 are arranged inside and outside the sealing ring 418.

A worm gear assembly 411 matched with the worm 422 is arranged on the stepped shaft 412, and needle bearings 410 and 413 and circlips 409 and 414 for holes are respectively sleeved at the front end and the rear end of the stepped shaft 412; the worm gear wheel assembly 411 is provided with a worm gear end and a gear section in sequence along the axial direction; the stepped shaft 412 is perpendicular to the worm 422, one end of the stepped shaft 412 is fixed in a stepped hole of the front shell 501, and the other end of the stepped shaft 412 passes through the transmission assembly 3 and is fixed in a shaft hole on the front end surface of the rear shell 101;

the front end of the parallel cylinder 403 is provided with a thrust bearing, and the thrust bearing is composed of a thrust needle roller, a retainer 401 and a thrust washer 402; a rear sealing ring 405 is arranged on the outer edge of the rear end of the parallel cylinder body 403, and a second piston framework oil seal 406 is arranged on the inner edge of the rear end of the cylinder body 403; the rear end of the cylinder 403 is fixed with the pump variable gear 407 through a gear transmission pin 408; the plunger 251 extends through the pump variable gear 407 and the second piston frame oil seal 409 into the parallel cylinder 403. The rear ends of the two parallel cylinder bodies 403 are respectively provided with a pump variable gear 407, the worm wheel section of the worm wheel gear combination 411 is meshed with the worm 422, and the gear section of the worm wheel gear combination 411 is meshed with the pump variable gear 407; the step motor 415 drives the worm gear 422 to rotate, so as to drive the parallel cylinder 403 to rotate, so that the displacement of the servo pump can be adjusted.

The pump variable component of the invention has two parallel cylinders and a pumping component to reduce flow pulsation. The double plungers move simultaneously through the gear structure of the transmission assembly and the pumping assembly connected in parallel. Meanwhile, the torque of the stepping motor is transmitted to a variable gear fixed with the parallel cylinder body through a worm gear transmission mechanism, and the cylinder body is driven to rotate to realize synchronous variable of the parallel cylinder body.

In the working process, a driving wheel in the transmission mechanism is driven by a pump motor to transmit to two driven wheels through inner engagement. The front cam is connected with the gear through a transmission pin to realize synchronous rotation and relative axial movement. The front cam and the rear cam are in line contact with the two contraposition cone idler wheels respectively, and end face tracks of the front cam and the rear cam are equal-acceleration equal-deceleration curved surfaces. Under the constraint of the cone roller set, the front cam and the rear cam drive the plunger to move axially while rotating circumferentially, so that the movement of the plunger is two-dimensional movement. However, the rotation speed of the plunger is the same as that of the driven wheel, so that only axial movement exists between the plunger and the linear bearing embedded in the driven wheel. When the plunger-double cam motion assembly rotates and reciprocates, a dynamic and static pressure sliding support structure is adopted, one end of the dynamic and static pressure sliding support structure is a dynamic pressure sliding support formed by the plunger and a cylinder body hole, and the other end of the dynamic pressure sliding support structure is a dynamic pressure sliding support formed by a right pump cover mandrel and a cam wheel hub hole. For the cylinder block, the cylinder block window is always communicated with the corresponding high-low pressure oil passage in the front shell. And the worm gear and the pump variable gear are driven to rotate through the stepping motor, so that the position of the window of the parallel cylinder body is changed.

Because the driven wheels driven by the two plungers are meshed with the same internal gear, the two plungers synchronously move in two dimensions under the condition that the initial cam phase is the same, and the pump displacement is changed by changing the rotating angle of the oil ports of the parallel cylinders. In the process of one rotation of the motor, the two-dimensional plunger pump realizes four times of oil suction and discharge, wherein each two times of oil suction and discharge are a period, and the period corresponds to a section of equal acceleration and equal deceleration trajectory curve of the front cam and the rear cam. And taking the state of the leftmost end of the plunger stroke as an initial working state, wherein the circumferential rotation angle of the corresponding cam is 0 degree. In the process of rotating from 0 degree to 90 degrees, the volume of the closed cavity is increased from minimum to maximum according to the law of equal acceleration and equal deceleration, and the oil absorption process is completed at the stage that the through groove of the plunger rod is communicated with the oil absorption window of the cylinder body. In the process of rotating from 90 degrees to 180 degrees, the volume of the closed cavity is reduced from maximum to minimum according to the law of equal acceleration and equal deceleration, and the oil discharge process is completed at the stage of communicating the oil discharge windows of the plunger rod groove cylinder body. If the pump displacement needs to be changed, a worm gear transmission mechanism is driven by a stepping motor to drive a pump variable gear and the parallel cylinder body to rotate around an axis, so that the position of an oil suction and discharge window of the parallel cylinder body is adjusted, and the oil displacement of the cylinder body in a rotation period is changed.

The embodiments described in this specification are merely illustrative of implementations of the inventive concept and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments but rather by the equivalents thereof as may occur to those skilled in the art upon consideration of the present inventive concept.

Claims (4)

1. The utility model provides a parallelly connected double piston bivariate servo pump which characterized in that: the pump comprises a front shell assembly (5) and a rear shell assembly (1) which are coaxially connected, wherein a pump variable assembly (4) is arranged in the front shell assembly (5), and a transmission assembly (3) and a pumping assembly (2) are arranged in the rear shell assembly (1);

the rear shell assembly (1) comprises a rear shell (101), a rear shell end cover (102) and a driving motor (103), wherein the driving motor (103) is arranged at the upper part of the rear side of the rear shell (101), two space cam-cone roller installation cavities which protrude backwards are arranged at the lower part of the rear side of the rear shell (101), and the two space cam-cone roller installation cavities are axisymmetric; a rear shell end cover (102) is arranged at the opening at the rear end of the space cam-cone roller mounting cavity, and a first mandrel is arranged at the center of the front end face of the rear shell end cover (102); a gear speed regulation disc is embedded on the front end face of the rear shell (101), the gear speed regulation disc comprises a copper ring (36), and a front baffle (37) and a rear baffle (31) which are arranged on the front side and the rear side of the copper ring (36), and the copper ring (36), the front baffle (37) and the rear baffle (31) enclose a transmission assembly installation cavity;

the transmission assembly (3) is arranged in the transmission assembly mounting cavity, the transmission assembly (3) comprises a circular ring-shaped internal gear (34), a driving wheel (35) and driven wheels (33), the upper part of the inner side of the internal gear (34) is internally meshed with the driving wheel (35), the two driven wheels (33) are symmetrically arranged at the lower part of the inner side of the internal gear (34), and the two driven wheels (33) are internally meshed with the internal gear (34); a motor shaft of the driving motor (103) penetrates through the rear shell (101) and the piston framework oil seal (32) to be connected with a driving wheel (34), and the driving wheel (34) transmits power to two driven wheels (33) which are symmetrically arranged below;

the pumping assembly (2) comprises a space cam-cone roller mechanism and a plunger, and the space cam-cone roller mechanism is arranged in a space cam-cone roller mounting cavity; the spatial cam-cone roller mechanism comprises a rear cam (211), two groups of cone rollers (221), a front cam (241) and a transmission sliding pin (253), wherein each group of cone rollers (221) comprises a pair of mutually vertical cone rollers (221); the two groups of conical rollers (221) are fixed in the space cam-conical roller mounting cavity in a staggered manner, and the axes of the two groups of conical rollers (221) are mutually vertical but do not intersect; the two groups of conical rollers (221) are respectively in contact fit with the end faces of the front cam (241) and the rear cam (211), the end faces of the front cam (241) and the rear cam (211) are deceleration curved surfaces with equal acceleration and the like, and the deceleration curved surfaces with equal acceleration and the like have axial fluctuation; the highest point of the front cam (241) corresponds to the highest point of the rear cam (211), and the lowest point of the front cam (241) corresponds to the lowest point of the rear cam (211);

the cam hub of the front cam (241) is inserted into the gear hub hole of the driven wheel (33), the gear hub hole and the outer cylindrical surface of the cam hub of the front cam (241) are respectively provided with a half pin hole, a transmission sliding pin (253) which is axially arranged is inserted into the pin holes, and the transmission sliding pin (253) connects the driven wheel (33) and the front cam (241), so that the driven wheel (33) and the front cam (241) can rotate together and can move axially and relatively; the front cam (241) is fixedly connected with the rear cam (211) and the plunger (251) through a long transmission pin (242) and an end transmission pin (243) in the radial direction, and the first mandrel is inserted into a central hole of the rear cam (211); the front end of the plunger (251) penetrates through the driven wheel (33) through a first linear bearing (252) along the axial direction, and the first linear bearing (252) is fixed in the driven wheel (33); the front cam (241) and the rear cam (211) rotate and are restrained by the cone roller (221) to realize axial movement;

the front shell assembly (5) comprises a front shell (501) and a controller cover (503), wherein the controller cover (503) is arranged at the upper part of the front end of the front shell (501), and a controller assembly is arranged in the controller cover (503); the lower part of the front end of the front shell (501) is provided with two cylinder body installation cavities protruding forwards and a worm and gear installation cavity, and the worm and gear installation cavity is positioned below the cylinder body installation cavity; the cylinder body mounting cavity is provided with a high-pressure oil port, a low-pressure oil port and an oil unloading port, the inner wall of the cylinder body mounting cavity is provided with a circular high-pressure oil duct and a circular low-pressure oil duct, the high-pressure oil duct is communicated with the high-pressure oil port, and the low-pressure oil duct is communicated with the low-pressure oil port; a front shell end cover (506) is arranged at an opening at the front end of the cylinder body mounting cavity, and a second spindle is arranged in the center of the rear end of the front shell end cover (506);

the pump variable component (4) comprises two parallel cylinder bodies (403) and a worm gear transmission mechanism, wherein the parallel cylinder bodies (403) are arranged in cylinder body mounting cavities, and the axes of the parallel cylinder bodies (403) are superposed with the axes of a front spindle of a front shell end cover (506), a plunger (251), a front cam (211), a rear cam (241) and a rear spindle of a rear shell end cover (102); a closed cavity is formed among the second mandrel, the parallel cylinder body (403) and the plunger (251), the volume of the closed cavity is changed along with the axial movement of the plunger (251), the volume is gradually increased when the plunger (251) moves from the foremost end to the rearmost end, and the volume is gradually reduced when the plunger (251) moves from the rearmost end to the foremost end;

two groups of flow distribution windows are axially arranged on the parallel cylinder body (403), and the positions of the two groups of flow distribution windows respectively correspond to the high-pressure oil duct and the low-pressure oil duct; each group of flow distribution windows comprises two flow distribution windows which are vertical to each other, and the two groups of oil distribution windows are arranged in a staggered manner; the left side, the middle and the right side of the two groups of flow distribution windows are respectively provided with a cylinder body sealing ring (404) for keeping the inlet oil and the outlet oil isolated from each other; a plunger through groove is formed in the plunger (251), a plunger through groove communicated with the plunger through groove is formed in the left end face of the plunger (251), and the plunger (251) is communicated with the two groups of flow distribution windows through the plunger through groove respectively; the closed cavity absorbs oil when the volume is increased and discharges oil when the volume is reduced;

the worm and gear transmission mechanism is arranged in the worm and gear installation cavity and comprises a stepping motor (415) and a worm (422); a worm and gear mounting cavity is perpendicular to two ends of the parallel cylinder body (403) and is respectively provided with a stepping motor (415) and a worm end cover (428), a motor shaft of the stepping motor (415) is perpendicular to the parallel cylinder body (403), and the motor shaft of the stepping motor (415) is connected with the worm (422) through a coupler (416); a worm gear and gear assembly (411) matched with the worm (422) is arranged on the stepped shaft (412), and a worm gear end and a gear section are sequentially arranged on the worm gear and gear assembly (411) along the axial direction; the stepped shaft (412) is perpendicular to the worm (422), one end of the stepped shaft (412) is fixed in a stepped hole of the front shell (501), and the other end of the stepped shaft (412) penetrates through the transmission assembly (3) and is fixed in a shaft hole in the front end face of the rear shell (101);

the rear ends of the two parallel cylinder bodies (403) are respectively provided with a pump variable gear (407), the worm wheel section of the worm wheel gear combination (411) is meshed with the worm (422), and the gear section of the worm wheel gear combination (411) is meshed with the pump variable gear (407); a stepping motor (415) drives the worm gear (422) to rotate, so that the parallel cylinder (403) is driven to rotate, and the displacement of the servo pump is adjustable.

2. A parallel double-plunger double-variable servo pump as claimed in claim 1, wherein: a front shell sealing ring (505) is arranged between the front shell end cover (506) and the front shell (501), and a front mandrel sealing ring (504) is sleeved on the front mandrel so as to realize the sealing between the front shell (501) and the parallel cylinder body (403).

3. A parallel double-plunger double-variable servo pump as claimed in claim 1, wherein: a conical roller shaft hole is formed in the space cam-conical roller mounting cavity at a position corresponding to the conical roller (221); an intermediate shaft hole is communicated between two conical roller shaft holes which are close to each other on the two space cam-conical roller mounting cavities, an intermediate shaft (233) is inserted into the intermediate shaft hole, and a long claw point slotted fastening screw (234) is mounted in a fastening screw hole at the middle section of the intermediate shaft hole for fastening; the cone roller shaft (233) is inserted into the cone roller shaft holes at other positions from the outer side, the cone roller shaft (233) sequentially penetrates through the cone roller retainer ring and the sealing ring to be fixed with the cone roller, the top of the cone roller shaft (223) is provided with an inner hexagonal flat end screw (225), and the cone roller shaft (223) is fixed in the cone roller shaft hole by the inner hexagonal flat end screw (225).

4. A parallel double-plunger double-variable servo pump as claimed in claim 1, wherein: the front end of the parallel cylinder body (403) is provided with a thrust bearing, and the thrust bearing consists of a thrust needle roller, a retainer (401) and a thrust washer (402); a rear sealing ring (405) is arranged on the outer edge of the rear end of the parallel cylinder body (403), and a second piston framework oil seal (406) is arranged on the inner edge of the rear end of the cylinder body (403); the rear end of the cylinder body (403) is fixed with the pump variable gear (407) through a gear transmission pin (408); the plunger (251) penetrates through a second pump variable gear (407) and a piston framework oil seal (409) and extends into the parallel cylinder body (403).

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