CN111502951B - Roller type force balance unit pump - Google Patents

Abstract

The roller type force balance unit pump has a rolling bearing installed between the right coupling and the right roller assembly; the left and right cams are symmetrically distributed on both sides of the pump core assembly with a phase difference of 90°; the roller assembly rolls on the cam surface, and four conical rollers are distributed on one side, and are fixed on the C-shaped roller bracket by a group of two pins. The copper sleeve of the pump core assembly and the cylinder body are provided with two pairs of rectangular high and low pressure oil holes evenly distributed in the circumferential direction, which are in contact with the first and second distribution grooves on the piston to absorb and discharge oil respectively; the cylinder body is provided with an annular oil groove connected with the high pressure oil hole, which gathers the oil flowing out of the two high pressure oil holes together; the mass of the rotor composed of the first roller bracket assembly, the third roller bracket assembly, the transmission shaft, and the left and right concentric rings should be equal to the sum of the mass of the rotor composed of the second roller group, the fourth roller bracket assembly, and the piston; the first high and low pressure chamber in the pump core is always in communication with the first distribution groove of the piston, and the second high and low pressure chamber is always in communication with the second distribution groove of the piston.

Description

Roller type force balance unit pump

Technical Field

The invention relates to a hydraulic plunger pump, belonging to a hydraulic pump and a hydraulic motor in the field of fluid transmission and control.

Background technique

As the power element of the hydraulic system, the hydraulic pump can transfer the mechanical energy of the prime mover or other external energy to the liquid to increase the liquid energy. It is widely used in engineering machinery and aerospace. However, due to the limitations of friction pairs and size, traditional plunger pumps have problems such as low efficiency, high vibration, high noise, and short life, making it difficult to achieve the goal of high speed and high pressure.

The most common traditional pump is the axial piston pump, which has many parts moving relative to each other, has high requirements for material quality and processing precision, is sensitive to oil contamination, has high requirements and costs for processing, use and maintenance, and is expensive; the cylinder body rotates with the transmission shaft, and has a large moment of inertia, resulting in slow response speeds for starting, stopping and speed regulation, which is not conducive to controlling the output flow of the pump through speed regulation; there are many friction pairs in the cylinder body, and the cylinder body temperature rises rapidly under high-speed rotation, and the wear of parts such as the distribution plate and plunger directly affects the service life and durability of the pump. In addition, due to the limitations of the working principle of the plunger pump itself, each plunger can only achieve one oil suction and one oil discharge for one rotation of the transmission shaft, and its displacement is limited.

Due to the various shortcomings of traditional plunger pumps, patent document CN205895515U proposes a new type of hydraulic pump, which uses the double-degree-of-freedom motion principle of the piston to rotate and move axially at the same time to achieve the oil suction and discharge functions. Because it has two-dimensional movement when working, it is named a two-dimensional 2D piston pump. The double-degree-of-freedom motion principle is applied to the piston design of the pump, forming a new flow distribution method.

Summary of the invention

In order to improve the shortcomings of the existing two-dimensional 2D piston pump, the present invention provides a roller-type force balance unit pump which utilizes the double degrees of freedom of the piston and can move axially while the plunger rotates to achieve continuous oil suction and discharge functions.

The technical implementation scheme of the present invention is as follows:

The roller type force balance unit pump is distributed along the axis in sequence: right end cover, right coupling assembly, right roller assembly, right cam, pump housing, pump core assembly, left cam, left roller assembly, left coupling assembly, and left end cover. The left end cover and right end cover are coaxially distributed with the left coupling and right coupling, and rolling bearing motion isolation is adopted. A rolling bearing is installed between the right coupling and the right roller assembly to prevent direct contact with the right roller assembly. The left and right cams are symmetrically distributed on both sides of the pump core assembly, with a phase difference of 90°. The roller assembly rolls on the cam surface, with four conical rollers distributed on one side. They are fixed to the C-shaped roller bracket in groups of two using pins. The group of rollers that contacts the right cam and whose C-shaped opening faces the cam surface is the first roller bracket assembly. The first roller bracket assembly includes a pair of conical rollers symmetrically distributed along the axis of the pump core, a C-shaped roller bracket, a rolling bearing, and a fixed pin. The group of rollers that contacts the right cam and whose C-shaped opening faces away from the cam surface is the second roller bracket assembly. The second roller bracket assembly includes a pair of conical rollers symmetrically distributed along the axis of the pump core, a roller bracket, a rolling bearing, and a fixed pin. The two groups of roller bracket assemblies are circumferentially fixed and axially relative to each other. The rollers are fixed to the roller bracket by pins. The group of rollers that contacts the left cam and whose C-shaped opening faces the cam surface is the third roller bracket assembly, and the group of rollers that contacts the left cam and whose C-shaped opening faces away from the cam surface is the fourth roller bracket assembly. The second roller bracket assembly and the fourth roller bracket assembly are fixed to the piston in a spline form, and the first roller bracket assembly and the third roller bracket assembly are fixed to the transmission shaft in a spline form. The installation method and movement method of the third roller bracket assembly are consistent with those of the first roller bracket assembly, and the fourth roller assembly is consistent with the second roller assembly. The installation phase angle of the first roller bracket assembly and the second roller bracket assembly differs by 90°, the first roller bracket assembly and the third roller bracket assembly have the same phase, and the second roller bracket assembly and the fourth roller bracket assembly have the same phase.

The pump core assembly includes a cylinder body, a piston, a copper sleeve, a transmission shaft, a left concentric ring, and a right concentric ring. The two ends of the piston are made into a spline shaft form to fix the second roller bracket assembly and the fourth roller bracket assembly. A pair of first distribution grooves and a pair of second distribution grooves are opened on the piston wall, and the first distribution grooves and the second distribution grooves are alternately evenly distributed. The first distribution groove and the second distribution groove are U-shaped distribution grooves with opposite axial openings, and the width of the U-shaped distribution groove is consistent with the width of the rectangular hole on the copper sleeve. The left concentric ring and the right concentric ring are respectively sleeved on the steps on both sides of the piston, and the installation directions are axially opposite. They are fixed to the first roller bracket assembly and the third roller bracket assembly using a fixed pin shaft. The outer circle of the transmission shaft is matched with the inner circle of the piston, and the transmission shaft and the piston move relative to each other in the axial direction. The two ends of the transmission shaft are made into a spline shaft form to fix the first roller bracket assembly and the third roller bracket assembly. The copper sleeve and the cylinder body are opened with two pairs of rectangular high and low pressure oil holes evenly distributed in the circumferential direction, which are in contact with the first and second distribution grooves on the piston to suck and discharge oil. The cylinder body is provided with an annular oil groove which is communicated with the high-pressure oil hole, and the oil flowing out of the two high-pressure oil holes is gathered together.

The mass of the rotor consisting of the first roller bracket assembly, the third roller bracket assembly, the transmission shaft, and the left and right concentric rings should be equal to the sum of the mass of the rotor consisting of the second roller group, the fourth roller bracket assembly, and the piston, because the inertial force generated by acceleration is balanced on the cam.

The left side of the right concentric ring in the pump core, the outer surface of the piston and the inner side of the copper sleeve form the first high and low pressure chamber, the right side of the left concentric ring, the outer surface of the piston and the inner side of the copper sleeve form the second high and low pressure chamber, the inner circle of the left and right concentric rings and the piston are in clearance, and the outer circle and the inner side of the copper sleeve are in clearance, forming a gap seal. The first high and low pressure chamber is always in communication with the first flow distribution groove of the piston, and the second high and low pressure chamber is always in communication with the second flow distribution groove of the piston.

When the first roller bracket assembly moves from the lowest point to the highest point of the right cam, it drives the concentric ring to rotate in the same direction and move to the right, while the second roller bracket assembly moves from the highest point to the lowest point of the right cam, driving the piston to move to the left. The first distribution groove on the piston is connected with the oil suction hole on the copper sleeve and the cylinder body, and the oil is sucked into the first high and low pressure chamber. When the first roller bracket assembly rotates, it drives the transmission shaft to rotate synchronously and move to the right through the spline, and transmits the motion to the third roller bracket assembly. The third roller bracket assembly moves from the highest point to the lowest point of the left cam, driving the left concentric ring to move to the right. The second roller bracket assembly transmits the motion to the fourth roller bracket assembly through the spline on the piston, driving the piston to move to the left, and the volume in the second high and low pressure chamber is reduced. The oil is discharged from the oil outlet through the second distribution groove on the piston. With the rotation of the roller assembly, the first distribution groove and the second distribution groove and the oil suction hole and the oil discharge hole on the concentric ring change periodically, realizing the roller-type inertial force balance unit pump suction and discharge oil.

Furthermore, the left end cover is fixed to the left side of the pump housing by bolts, and the right end cover is fixed to the right end of the pump housing by bolts. A sealing ring is used to seal the left and right end covers and the pump housing. The cylinder body is fixed to the right end of the pump housing by bolts, and a sealing ring is used to seal the cylinder body and the pump housing.

Furthermore, the oil suction and discharge holes on the copper sleeve are completely consistent in position with the oil suction and discharge holes on the cylinder body, and the outer circle of the copper sleeve and the inner circle of the cylinder body are fixed by interference fit.

The beneficial effects of the present invention are mainly manifested in:

1. The volume change is completed by the cooperation of the piston and the concentric ring, which doubles the volume change of a single piston and saves space. When the stroke and displacement remain unchanged, the cross-sectional area is reduced, the force on the guide rail and the tapered roller is reduced, and high load is easily achieved.

2. The roller rotation method is adopted, which is simpler in structure than the cam rotation force balance unit pump and greatly enhances the movement reliability.

3. By utilizing the inertial forces of different roller groups in opposite directions and balancing the masses of different rotors, the inertial forces on the cylinder body can be balanced, reducing the mechanical vibration during operation, making the motor output speed more stable, and reducing flow pulsation. At the same time, the motor output torque can be reduced to save energy.

4. Through the special coupling structure, the rotor is partially wrapped in a closed cavity, which greatly reduces the oil stirring loss generated when the rotor rotates and improves the mechanical efficiency of the pump.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the assembly of a roller-type force balance unit pump according to the present invention.

FIG. 2 is a schematic diagram of the internal assembly of the present invention.

Fig. 3a to Fig. 3b are schematic diagrams of the right coupling assembly of the present invention, wherein Fig. 3a is an inner side view of the right coupling assembly, and Fig. 3b is an outer side view of the right coupling assembly.

4a and 4b are schematic diagrams of a left coupling assembly of the present invention, wherein FIG. 4a is an inner view of the left coupling assembly, and FIG. 4b is an outer view of the left coupling assembly.

Fig. 5a to Fig. 5b are schematic diagrams of the left end cover structure of the present invention, wherein Fig. 5a is an outer side view of the left end cover, and Fig. 5b is an inner side view of the left end cover.

FIG. 6 is a schematic diagram of the structure of the right end cover of the present invention.

Figures 7a to 7d are schematic diagrams of the roller assembly of the present invention, wherein Figure 7a is a schematic diagram of the roller assembly, Figure 7b is a schematic diagram of the end face of the roller assembly, Figure 7c is a C-C sectional view of Figure 7b, and Figure 7d is a B-B sectional view of Figure 7b.

FIG. 8 is a schematic diagram of the concentric ring structure of the present invention.

FIG. 9 is a schematic diagram of the piston structure of the present invention.

FIG. 10 is a schematic diagram of the transmission shaft structure of the present invention.

FIG. 11 is a schematic diagram of the distribution of the roller assembly coupling of the present invention.

FIG. 12 is a schematic diagram of a pump core assembly of the present invention.

Figures 13a to 13c are schematic structural diagrams of the cylinder copper sleeve assembly of the present invention, Figure 13a is an end view of the cylinder copper sleeve assembly, Figure 13b is a side view of the cylinder copper sleeve assembly, and Figure 13c is an A-A sectional view of Figure 13b.

14a to 14c are schematic diagrams of the cam structure of the present invention, FIG. 14a is a front view of the cam, FIG. 14b is a side view of the cam, and FIG. 14c is a rear view of the cam.

Figures 15a and 15b are schematic diagrams of the pump casing structure of the present invention, Figure 15a is a front view of the pump casing structure, and Figure 15b is a cross-sectional view taken along the line A-A of Figure 15a.

Figures 16a to 16e are cross-sectional views of the flow channel at different angles of the present invention, wherein Figure 16a is a cross-sectional view of the flow channel when the rotation angle is 0°, Figure 16b is a cross-sectional view of the flow channel when the rotation angle is 45°, Figure 16c is a cross-sectional view of the flow channel when the rotation angle is 90°, Figure 16d is a cross-sectional view of the flow channel when the rotation angle is 135°, and Figure 16e is a cross-sectional view of the flow channel when the rotation angle is 180°.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

The roller force balancing unit pump of the present invention comprises: a right coupling assembly 1R, a right end cover 3, a left roller assembly 4L and a right roller assembly 4R, a pump core assembly 5, a pump housing 6, a left end cover 8, and a left coupling 1L. The right end cover 3 is connected to the right end face of the pump housing 6 by bolts, and the left end cover 8 is fastened to the left end face of the pump housing 6 by bolts. The sealing between the right end cover 3 and the pump housing 6 and the left end cover 8 and the pump housing 6 mainly relies on the sealing ring 7. The right coupling 1R is axially positioned with the right end cover 3 by a rolling ball bearing 10. The rolling ball bearing 10 realizes the motion isolation of the right coupling 1R and the right end cover 3, and the right coupling 1R can complete the rotational motion. The sealing between the right coupling 1R and the right end cover 3 mainly relies on the gap seal, and the trapezoidal groove 2 on the right end cover 3 is to prevent the escape of volatile harmful gases in the oil. The inner wall surface of the right coupling assembly 1R is evenly distributed with four rolling bearings 12, which are fixed to the coupling 11 through a pin 13. The right coupling assembly 1R and the right roller assembly 4R are in contact through the rolling bearings 12, ensuring that there is no relative sliding when the right roller assembly 4R and the right coupling assembly 1R make relative axial movement. The four rolling bearings 12 are embedded between the first roller bracket assembly 14 and the second roller bracket assembly 15.

The right roller assembly 4R includes a first roller bracket assembly 14, a second roller bracket assembly 15, and a right concentric ring 172. The first roller bracket assembly 14 includes a roller 144, a rolling bearing 1414, a first roller bracket 142, and a fixed pin 143. The roller 144 and the rolling bearing 141 are fixed to the first roller bracket 142 through the fixed pin 143. The first roller bracket assembly 14 is fixed to the transmission shaft 16 through the spline 16a, and the right concentric ring 172 is fixed to the first roller bracket 141 through the pin hole 172a and the fixed pin 143. The transmission shaft 16, the right concentric ring 172, and the first roller bracket assembly 14 are fixedly connected and move synchronously. The second roller bracket assembly 15 includes a rolling bearing 151, a second roller bracket 152, a fixed pin 153, and a roller 154. The rolling bearing 151 and the roller 154 are fixed to the second roller bracket 152 through the fixed pin. The second roller assembly 15 and the piston 18 are fixedly connected by the spline 18a and move synchronously. The first roller support assembly 14 and the second roller support assembly 15 rotate synchronously by the circumferential constraint of the rolling bearing 12, but there is no axial constraint, that is, the first roller support assembly 14 and the second roller support assembly 15 are allowed to have axial relative movement. The installation positioning and movement relationship of the right roller assembly 4R and the left roller assembly 4L are consistent, and the two pairs of rollers in the same direction are regarded as the same assembly.

The pump core assembly 5 includes a transmission shaft 16, a piston 18, a right concentric ring 172, a left concentric ring 171, a right cam 19R, a left cam 19L, a filter 20, a cylinder body 21, and a copper sleeve 22. The cylinder body 21 is fixed with bolts through a through hole 21a and a threaded hole 6a on the pump housing 6 to achieve the positioning of the pump core assembly. The right cam 19R has a positioning pin hole 19Ra, which is fixed in the positioning pin hole 21e on the cylinder body 21 using a positioning pin shaft. According to the shape of the cam surface of the right cam 19R, the cam stroke can be divided into two parts, from the lowest point to the highest point is the lift, from the highest point to the lowest point is the return stroke, the highest point is called the peak point, and the lowest point is called the valley point. Each cam has two peak points and two valley points, that is, each cam has two sections of lift and two sections of return, each section is 90°. The copper sleeve 22 is fixed in the inner ring of the cylinder body 21 by means of interference fit, and the high-pressure oil hole 22a and the low-pressure oil hole 22b in the copper sleeve 22 are respectively connected with the high-pressure oil hole 21b and the low-pressure oil hole 21c in the cylinder body 21. The annular groove 21d in the cylinder body 21 is connected with the oil discharge port 6b on the pump housing, and the oil can flow out from the two high-pressure oil holes 22a of the cylinder body 21, and converge through the annular groove 21d to flow out from the oil discharge port 6b on the pump housing.

The installation phases of the left cam 19L and the right cam 19R of the roller type force balance unit pump differ by 90°, that is, the peak point of the left cam 19L is opposite to the valley point of the right cam 19R, the lift of the left cam 19L is opposite to the return stroke of the right cam 19R, and the installation phase angles of the first roller bracket assembly 14 and the second roller bracket assembly 15 differ by 90°. When the first roller assembly 14 moves from the valley point to the peak point along the right cam 19R and moves from the peak point to the valley point along the left cam 19L, the second roller assembly 15 moves from the peak point to the valley point along the left cam 19L and moves from the valley point to the peak point along the right cam 19R. The left cam 19L and the right cam 19R are a pair of identical cams, and their installation phase angles differ by 90°, and the change rules of the cam curve surfaces are also completely consistent. The cam surface adopts the law of equal acceleration and equal deceleration. The first roller assembly 14 performs uniform rotation in the circumferential direction. In the process of moving from the valley point to the peak point along the right cam surface, the axial direction performs uniform acceleration with a fixed acceleration, the speed direction is to the right, and the acceleration distance is a rotation angle of 45°. Then, it starts to perform uniform deceleration, the speed direction is unchanged, the acceleration direction is to the left, and the deceleration distance is a rotation angle of 45°, until the first roller bracket assembly 14 reaches the peak point of the right cam 19R, the speed is exactly the same as the valley point, which is 0. The second roller bracket assembly 15 rotates synchronously with the first roller bracket assembly 14. In the process of moving from the valley point to the peak point along the left cam surface, the axial direction performs uniform acceleration with a fixed acceleration, the speed direction is to the left, and the acceleration distance is a rotation angle of 45°. Then, it starts to perform uniform deceleration, the speed direction is unchanged, the acceleration direction is to the right, and the deceleration distance is a rotation angle of 45°, until the second roller bracket assembly 15 reaches the peak point of the left cam 19L, the speed is exactly the same as the valley point, which is 0. During the movement, the first roller bracket assembly 14 and the second roller bracket assembly 15 are subjected to accelerations of the same magnitude and opposite directions. When the sum of the masses of the first roller bracket assembly 14, the transmission shaft 16, the left concentric ring 171, and the right concentric ring 172 is equal to the sum of the masses of the second roller bracket assembly 15 and the piston 18, the inertial force of the first roller bracket assembly 14 acting on the cam is the same in magnitude and opposite in direction as the inertial force of the second roller bracket assembly acting on the cam, and the inertial force indirectly acting on the cylinder body and the pump housing is offset, achieving inertial force balance.

The left end cover 8 of the roller type force balance unit pump is connected to the external oil circuit. The hydraulic oil enters the pump housing through the four waist-shaped holes 8a on the left end cover 8, fills the left chamber inside the left end cover 8, and enters the right chamber inside the right end cover 3 through the connecting hole 21f on the cylinder body 21. The oil in the two chambers can play a role in lubricating the friction pair. On the other hand, the oil passes through the connecting hole 21f, the low-pressure oil hole 21c of the cylinder body and the low-pressure oil hole 22b on the copper sleeve, and enters the first high-low pressure chamber B or the second high-low pressure chamber A through the first distribution groove 18c or the second distribution groove 18b on the piston 18 connected to the low-pressure oil hole 22b on the copper sleeve. The high-pressure oil enters the annular groove 21d of the cylinder body 21 from the second high-low pressure chamber A or the first high-low pressure chamber B through the second distribution groove 18b or the first distribution groove 18c on the piston 18 and the high-pressure oil hole 22a and the high-pressure oil hole 21b connected thereto, and is discharged from the unit pump through the oil discharge port 6b on the pump housing 6. The second high-low pressure chamber A is a closed chamber formed by the inner circular surface of the copper sleeve 22, the right end surface of the left concentric ring 161, and the piston 18. The first high-low pressure chamber B is a closed chamber formed by the inner circular surface of the copper sleeve 22, the left end surface of the right concentric ring 172, and the piston 18.

working principle

The roller type force balance unit pump drives the right coupling assembly 1R in the right end cover 3 to rotate through an external motor, thereby driving the first roller support assembly 14 and the second roller support assembly 15 to perform synchronous rotation. The first roller support assembly 14 moves to the right under the constraint of the right cam 19R, and drives the right concentric ring 172 to move to the right through the fixed constraint pin 143. At the same time, the second roller support assembly 15 moves to the left under the constraint of the left cam 19L, and drives the piston 18 to move to the left through the fixed connection 18a, so that the volume of the first high and low pressure chamber B increases and the volume of the second high and low pressure chamber A decreases. The external oil channel of the oil enters the left end cover 8, enters the inside of the left end cover through the waist-shaped hole 8a on the left end cover 8, and enters the low-pressure oil hole 22b on the copper sleeve 22 through the connecting holes 21f and 21c on the cylinder body 21. At this time, the first distribution groove 18c on the piston is connected to the low-pressure oil hole 22b on the copper sleeve, and the oil is sucked into the first high and low pressure chamber B through the first distribution groove 18c. The volume of the second high- and low-pressure chamber A is reduced, so that the oil pressure in the second high- and low-pressure chamber A increases, and the oil is pressed into the annular groove 22d through the second distribution groove 18b on the piston, the high-pressure oil hole 22a on the copper sleeve 22, and the high-pressure oil hole 21b on the cylinder body, and the oil is discharged through the oil discharge port on the pump housing 6.

When rotating 45°, the first roller support assembly 14 moves to the extreme position, i.e., the rightmost end of the stroke, under the constraint of the right cam 19R, and the second roller support assembly 15 moves to the leftmost end of the stroke under the constraint of the left cam 19L. At this time, the first high-low pressure chamber B is in the maximum volume state, the second high-low pressure chamber A is in the minimum volume state, and the connecting area between the second distribution groove 18b and the high-pressure oil hole 22a and the low-pressure oil hole 22b on the copper sleeve and the connecting area between the first distribution groove 18c and the high-pressure oil hole 22a and the low-pressure oil hole 22b on the copper sleeve are zero. Then the first roller support assembly 14 moves to the left under the constraint of the left cam 19L, and the second roller support assembly 15 moves to the left under the constraint of the right cam 19R, so that the volume of the second high-low pressure chamber A increases and the volume of the first high-low pressure chamber B decreases. The oil enters the left end cover 8 through the external oil passage, enters the inside of the left end cover through the waist-shaped hole 8a on the left end cover 8, and enters the low-pressure oil hole 22b on the copper sleeve 22 through the connecting holes 21f and 21c on the cylinder body 21. At this time, the second distribution groove 18b on the piston is connected to the low-pressure oil hole 22b on the copper sleeve, and the oil is sucked into the second high-low pressure chamber A through the second distribution groove 18b. The volume of the first high-low pressure chamber B is reduced, so that the oil pressure in the first high-low pressure chamber B increases, and the oil is pressed into the annular groove 22d through the first distribution groove 18c on the piston, the high-pressure oil hole 22a on the copper sleeve 22, and the high-pressure oil hole 21b on the cylinder body, and the oil is discharged through the oil discharge port on the pump housing 6.

When rotating 90°, the first roller support assembly 14 and the second roller support assembly 15 are at the middle position at the same time, at which time the second distribution groove 18b on the piston and the high-pressure oil hole 22a on the copper sleeve, and the first distribution groove 18c and the low-pressure oil hole 22b on the copper sleeve are in the maximum contact state. The first roller support assembly 14 still moves to the left under the constraint of the left cam 19L, and the second roller support assembly 15 still moves to the left under the constraint of the right cam 19R, so that the volume of the second high and low pressure chamber A continues to increase, and the volume of the first high and low pressure chamber B continues to decrease.

When rotating 135°, the first roller support assembly 14 moves to the leftmost end of the stroke under the constraint of the left cam 19L, and the second roller support assembly 15 moves to the rightmost end of the stroke under the constraint of the right cam 19R. At this time, the second high and low pressure chamber A is in the maximum volume state, and the first high and low pressure chamber B is in the minimum volume state. At this time, the connecting area between the second distribution groove 18b and the high pressure oil hole 22a and the low pressure oil hole 22b on the copper sleeve and the connecting area between the first distribution groove 18c and the high pressure oil hole 22a and the low pressure oil hole 22b on the copper sleeve are zero. The first roller support assembly 14 moves to the right under the constraint of the right cam 19R, and the second roller support assembly 15 moves to the left under the constraint of the left cam 19L, so that the volume of the first high and low pressure chamber B increases and the volume of the second high and low pressure chamber A decreases. The oil enters the left end cover 8 through the external oil passage, enters the inside of the left end cover through the waist-shaped hole 8a on the left end cover 8, and enters the low-pressure oil hole 22b on the copper sleeve 22 through the connecting holes 21f and 21c on the cylinder body 21. At this time, the first distribution groove 18c on the piston is connected to the low-pressure oil hole 22b on the copper sleeve, and the oil is sucked into the first high-low pressure chamber B through the first distribution groove 18c. The volume of the second high-low pressure chamber A is reduced, so that the oil pressure in the second high-low pressure chamber A increases, and the oil is pressed into the annular groove 22d through the second distribution groove 18b on the piston, the high-pressure oil hole 22a on the copper sleeve 22, and the high-pressure oil hole 21b on the cylinder body, and the oil is discharged through the oil discharge port on the pump housing 6.

Next, the roller type force balance unit pump is driven by the motor to perform the above-mentioned periodic motion. When the motor rotates one cycle, that is, 360°, the roller assembly of the roller type force balance unit pump completes two complete axial reciprocating motions, and the first high and low pressure chamber A and the second high and low pressure chamber B complete complete oil suction and discharge twice.

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 (2)

1. Roller formula force balance unit pump, its characterized in that: a right end cover, a right coupler assembly, a right roller assembly, a right cam, a pump shell, a pump core assembly, a left cam, a left roller assembly, a left coupler assembly and a left end cover are sequentially distributed along the axial direction; the left end cover and the right end cover are coaxially distributed with the left coupler assembly and the right coupler assembly, and are isolated by adopting rolling bearing movement; a rolling bearing is arranged between the right coupler component and the right roller component; the left cam and the right cam are symmetrically distributed on two sides of the pump core assembly, and the phase difference is 90 degrees; the roller assembly rolls on the cam surface, four cone rollers are distributed on one side, two groups of the cone rollers are fixed on a C-shaped roller support through pin shafts, one group of rollers which are contacted with the right cam and have C-shaped openings towards the cam surface are first roller support assemblies, each first roller support assembly comprises a pair of cone rollers, a C-shaped roller support, a rolling bearing and a fixed pin shaft which are symmetrically distributed along the axis of the pump mandrel, one group of rollers which are contacted with the right cam and have C-shaped openings opposite to the cam surface are second roller support assemblies, and each second roller support assembly comprises a pair of cone rollers, roller supports, rolling bearings and fixed pin shafts which are symmetrically distributed along the axis of the pump mandrel; the two groups of roller bracket components are fixed in the circumferential direction and move axially relatively; the idler wheel is fixed on the idler wheel frame in a pin shaft mode; the group of rollers which are contacted with the left cam and the C-shaped opening faces the cam surface is a third roller bracket component, and the group of rollers which are contacted with the left cam and the C-shaped opening faces away from the cam surface is a fourth roller bracket component; the second roller bracket component and the fourth roller bracket component are fixed on the piston in a spline mode, and the first roller bracket component and the third roller bracket component are fixed on the transmission shaft in a spline mode; the mounting mode and the movement mode of the third roller bracket component are consistent with those of the first roller bracket component, and the fourth roller bracket component is consistent with that of the second roller bracket component; the installation phase angles of the first roller bracket component and the second roller bracket component differ by 90 degrees, the phase positions of the first roller bracket component and the third roller bracket component are the same, and the phase positions of the second roller bracket component and the fourth roller bracket component are the same;

The pump core assembly comprises a cylinder body, a piston, a copper sleeve, a transmission shaft, a left concentric ring and a right concentric ring; the two ends of the piston are made into spline shafts, and the second roller bracket component and the fourth roller bracket component are fixed; the wall surface of the piston is provided with a pair of first distributing grooves and a pair of second distributing grooves, the first distributing grooves and the second distributing grooves are alternately and uniformly distributed, the first distributing grooves and the second distributing grooves are U-shaped distributing grooves with opposite axial openings, and the width of the U-shaped distributing grooves is consistent with the width of the rectangular holes on the copper sleeve; the left concentric ring and the right concentric ring are respectively sleeved on steps at two sides of the piston, the installation directions are axially opposite, and the left concentric ring and the right concentric ring are fixed on the first roller bracket component and the third roller bracket component by using fixed pin shafts; the outer circle of the transmission shaft is in clearance fit with the inner circle of the piston, and the transmission shaft and the piston axially move relatively; two ends of the transmission shaft are made into spline shafts, and the first roller bracket component and the third roller bracket component are fixed; two pairs of rectangular high-low pressure oil holes uniformly distributed in the circumferential direction are formed in the copper sleeve and the cylinder body and respectively contact with the first and second distributing grooves on the piston to suck and discharge oil; an annular oil groove communicated with the high-pressure oil holes is formed in the cylinder body, and oil flowing out of the two high-pressure oil holes is converged;

The mass of the rotor formed by the first roller bracket component, the third roller bracket component, the transmission shaft and the left and right concentric rings is equal to the sum of the mass of the rotor formed by the second roller bracket component, the fourth roller bracket component and the piston, and the inertial force generated by acceleration is balanced on the cam;

the left side surface of the right concentric ring, the outer surface of the piston and the inner side surface of the copper bush in the pump core form a first high-low pressure cavity, the right side surface of the left concentric ring, the outer surface of the piston and the inner side surface of the copper bush form a second high-low pressure cavity, the inner circles of the left concentric ring and the right concentric ring are in clearance fit with the piston, and the outer circles of the left concentric ring and the right concentric ring are in clearance fit with the inner side surface of the copper bush to form clearance seal; the first high-low pressure cavity is communicated with the first distributing groove of the piston all the time, and the second high-low pressure cavity is communicated with the second distributing groove of the piston all the time;

in the process that the first roller bracket component moves from the lowest point to the highest point of the right cam, the concentric rings are driven to rotate in the same direction and move rightwards, the second roller bracket component moves from the highest point to the lowest point of the right cam, the piston is driven to move leftwards, the first distributing groove on the piston is communicated with the copper sleeve and the oil suction hole on the cylinder body, and oil is sucked into the first high-low pressure cavity; the first roller support assembly rotates and drives the transmission shaft to synchronously rotate and move rightwards through the spline, the movement is transmitted to the third roller support assembly, and the third roller support assembly moves from the highest point of the left cam to the lowest point to drive the left concentric ring to move rightwards; the second roller bracket component transmits the motion to the fourth roller bracket component through a spline on the piston to drive the piston to move leftwards, the volume in the second high-low pressure cavity is reduced, and oil is discharged from the oil outlet through a second distributing groove on the piston; along with the rotary motion of the roller assembly, the first distributing groove and the second distributing groove are periodically changed with the oil suction holes and the oil discharge holes on the concentric rings, so that the pumping oil discharge of the roller type inertial force balancing unit is realized;

The left end cover is connected with an external oil way, and hydraulic oil enters the pump shell through four waist-shaped holes on the left end cover;

The left end cover is fixed on the left side surface of the pump shell through a bolt, and the right end cover is fixedly connected with the right end surface of the pump shell through a bolt; the left end cover, the right end cover and the pump shell are sealed by sealing rings; the cylinder body is fixedly connected to the right end face of the pump shell through bolts, and the cylinder body is sealed with the pump shell through a sealing ring.

2. The roller type force balance unit pump of claim 1, wherein: the positions of the oil suction and discharge holes on the copper bush are completely consistent with those of the oil suction and discharge holes on the cylinder body, and the outer circle of the copper bush is fixed with the inner circle of the cylinder body in an interference fit mode.