An aero-cylinder pump with a floating return mechanism

Abstract

The application discloses an aviation plunger pump with a floating return mechanism, a mounting seat is communicated with an internal cavity of a shell, an internal cylinder is arranged, a main shaft is coaxially and fixedly connected in the internal cylinder and is fixedly connected with an external power device; a swash plate is rotationally arranged on the mounting seat, a stepped counterbore is formed in an end face of the swash plate, a through hole is coaxially formed in the center of a bottom sink pad for the main shaft to pass through, and an annular platform between the two-stage counterbores is a step; a wear-resistant disc is arranged at the bottom of the sink pad; a flat end of a sliding shoe in a plunger assembly is located between a return disc and the wear-resistant disc, a concave end penetrates through a mounting hole of the return disc and is hingedly connected with a plunger head, and the plunger is arranged in parallel in the internal cylinder; a pressure plate is fixedly connected on the step, and an inner diameter of the pressure plate is smaller than an outer diameter of the return disc; an adjusting pad is fixedly connected between the pressure plate and the swash plate, and an inner diameter of the adjusting pad is larger than the outer diameter of the return disc; an oil guide groove is formed in a circumferential direction of one side of the pressure plate which faces the return disc.

Description

Technical Field

[0001] This invention relates to the field of aviation hydraulics, and more particularly to an aviation piston pump with a floating return mechanism. Background Technology

[0002] As the power component of an aircraft's hydraulic system, the aviation hydraulic pump plays a crucial role in flight control and safety. The return mechanism, as the variable control unit of the aviation hydraulic pump, is primarily used to adjust the pump's displacement to meet the hydraulic system's needs under different operating conditions. In practice, existing piston pumps often employ either a ball joint with internal support for the return disc or a threaded sleeve to clamp the return disc. However, using a ball joint support structure presents challenges due to the difficulty of spherical grinding. Under high-speed pump operation, intense friction between the return disc and the ball joint can lead to ball joint erosion over time, causing pump failure. Using a threaded sleeve to clamp the return disc can result in uneven wear between the sleeve and the disc due to the thread helix angle. Prolonged operation can cause the sleeve to loosen, posing a risk of the return disc breaking. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes an aviation plunger pump with a floating return mechanism.

[0004] The specific technical solution is as follows:

[0005] An aviation plunger pump with a floating return mechanism includes: a mounting base, a housing, a cylinder, a main shaft, a swashplate, a swashplate bearing, a plunger assembly, and wear-resistant discs, a return disc, an adjusting shim, and a pressure plate arranged coaxially from front to back; the rear end face of the mounting base is sealed to the front end face of the housing, and a communicating cavity is formed inside the mounting base and the housing; the cylinder is installed in the cavity inside the housing, and the main shaft passes through a through hole coaxially formed in the center of the cylinder and is fixedly connected to it; the main shaft is rotatably mounted on the mounting base and the housing through bearings and is fixedly connected to an external power unit;

[0006] The swash plate is a flat cylinder with two stepped countersunk holes coaxially formed on its front face. The first-stage countersunk hole starts from the front face, and the second-stage countersunk hole starts from the bottom face of the first-stage countersunk hole, with a smaller diameter than the first-stage countersunk hole. A through hole is coaxially formed in the center of the second-stage countersunk hole for the spindle to pass through. The recessed structure formed by the second-stage countersunk hole is called the countersunk platform, and the annular platform between the two countersunk holes is called the step. Shafts are fixed to both radial ends of the swash plate and are respectively interference-fitted onto the inner ring of the swash plate bearing, which is arranged on a mounting base. The wear-resistant disc is coaxially mounted on the bottom of the countersunk platform.

[0007] The plunger assembly includes a plunger and a slipper. One end of the slipper is flat and is located between and in contact with the return plate and the wear plate. The other end is concave and passes through the mounting hole of the return plate to receive and hinge the plunger head. The plunger is arranged parallel to the cavity inside the cylinder body.

[0008] The pressure plate is fixedly installed on the step and has a ring structure with an inner diameter smaller than the outer diameter of the return plate, which is used to axially constrain the return plate; the adjusting pad is arranged between the pressure plate and the swash plate and has a ring structure with an inner diameter larger than the outer diameter of the return plate; the side of the pressure plate that contacts the return plate has several oil guide grooves evenly opened in the circumference.

[0009] Furthermore, the wear-resistant disc is a disc structure with a through hole coaxially opened in the center. The size of the through hole is the same as the size of the through hole opened in the center of the swashplate. The wear-resistant disc is coaxially installed on the bottom of the swashplate by a positioning pin.

[0010] Furthermore, the return disk is a disc structure with a through hole coaxially formed at the center for the main shaft to pass through; multiple mounting holes are also uniformly formed around the outer periphery of the through hole of the return disk for mounting the plunger assembly.

[0011] Furthermore, the pressure plate and the adjusting pad are fixedly installed on the step of the swashplate by a threaded connection.

[0012] Furthermore, it also includes a front bearing and a rear bearing; the front bearing, the main shaft, and the rear bearing are arranged coaxially in sequence, the front bearing is fixed to the mounting base, and the rear bearing is fixed to the housing; one end of the main shaft is mounted on the inner ring of the front bearing, and the other end is mounted on the inner ring of the rear bearing.

[0013] Furthermore, the main shaft and the cylinder are fixedly connected by a spline pair, wherein the main shaft has an external spline and the cylinder has an internal spline that mates with the main shaft in the central through hole.

[0014] The beneficial effects of this invention are:

[0015] (1) The present invention adopts a structure without ball joint support for floating installation of return plate and pressure plate. The return plate and pressure plate are in intermittent floating contact during the movement. The floating gap can be adjusted by using shims of different thicknesses to reduce the impact between pressure plate and return plate during pump operation.

[0016] (2) The present invention provides an oil guide groove on the pressure plate to facilitate lubrication between the pressure plate and the return plate, reduce the friction during the movement of the return plate, and improve the working efficiency of the pump. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of an aviation plunger pump with a floating return mechanism in an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the swashplate in an embodiment of the present invention.

[0019] Figure 3 This is a partial cross-sectional view of the return mechanism assembly in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the wear-resistant disc in an embodiment of the present invention.

[0021] Figure 5 This is a schematic diagram of the return disk in an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of the structure of the adjustment pad in an embodiment of the present invention.

[0023] Figure 7 This is a schematic diagram of the pressure plate structure in an embodiment of the present invention.

[0024] In the diagram, 1 is the mounting base, 2 is the front bearing, 3 is the spindle, 4 is the swashplate, 5 is the wear-resistant disc, 6 is the plunger assembly, 7 is the housing, 8 is the rear bearing, 9 is the cylinder block, 10 is the swashplate bearing, 11 is the pressure plate, 12 is the adjusting shim, and 13 is the return plate. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The objectives and effects of the present invention will become clearer as a result. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] like Figure 1 As shown, an aviation plunger pump with a floating return mechanism includes: a mounting base 1, a front bearing 2, a main shaft 3, a swashplate 4, a wear-resistant disc 5, a plunger assembly 6, a housing 7, a rear bearing 8, a cylinder block 9, a swashplate bearing 10, a pressure plate 11, an adjusting shim 12, and a return disc 13.

[0027] The rear end face of the mounting base 1 is mounted opposite the front end face of the housing 7, and a sealing groove is formed on the outer periphery of the end face where the two meet, in which a sealing ring is arranged to achieve a seal between the mounting base 1 and the housing 7. A communicating cavity is formed inside the mounting base 1 and the housing 7. The cylinder 9 is installed in the cavity inside the housing 7. A through hole is coaxially formed inside the cylinder 9, and the main shaft 3 is coaxially arranged in this through hole. An external spline is formed on the main shaft 3, and an internal spline that mates with the main shaft 3 is formed in the through hole at the center of the cylinder 9. The connection between the cylinder 9 and the main shaft 3 is achieved through the spline pair, ensuring that the cylinder 9 rotates synchronously with the main shaft 3. The front bearing 2, the main shaft 3, and the rear bearing 8 are arranged coaxially in sequence. The front bearing 2 is fixed to the mounting base 1, and the rear bearing 8 is fixed to the housing 7. One end of the main shaft 3 is mounted on the inner ring of the front bearing 2, and the other end is mounted on the inner ring of the rear bearing 8, allowing the main shaft 3 to rotate freely around its axis and ensuring the stability and accuracy of the rotation of the main shaft 3. Based on the working conditions, determine the assembly relationship between the spindle 3 and the front bearing 2 and the rear bearing 8. Under light load conditions, the spindle 3 adopts a transition fit or clearance fit with the front bearing 2 and the rear bearing 8; under heavy load conditions, the spindle 3 adopts a transition fit or interference fit with the front bearing 2 and the rear bearing 8.

[0028] like Figure 2 As shown, the swashplate 4 is a flat cylinder with two stepped countersunk holes coaxially formed on one end face. These stepped countersunk holes are used to install the return mechanism; as... Figure 3 As shown, the return mechanism includes: a plunger assembly 6, and a wear-resistant disc 5, a return disc 13, an adjusting shim 12, and a pressure plate 11 arranged coaxially in sequence. The first-stage countersunk hole starts from the end face, and the second-stage countersunk hole starts from the bottom face of the first-stage countersunk hole, with a diameter smaller than that of the first-stage countersunk hole. A through hole is coaxially opened at the center of the second-stage countersunk hole for the spindle 3 to pass through. The sunken structure formed by the second-stage countersunk hole is called a countersunk platform, and the annular platform formed between the two countersunk holes due to the difference in diameter is called a step. Several threaded holes are opened on the step for installing the adjusting shim 12 and the pressure plate 11. A through hole is also coaxially opened at the center of the swashplate 4, through which the spindle 3 can pass, and after installation, the swashplate 4 has a certain tilt angle relative to the spindle 3. Shafts are fixed to both radial ends of the swashplate 4. The shafts at both ends of the swashplate 4 are mounted on the inner ring of the swashplate bearing 10 and are interference-fitted with it. The outer ring of the swashplate bearing 10 is mounted on the bearing housing. Unlike the existing swashplate mounting method, the bearing housing and the mounting base 1 of the present invention are integrated structures, eliminating the need to install the bearing housing on the mounting base 1 by mechanical connection, thus reducing the assembly error of the parts.

[0029] like Figure 4 As shown, the wear-resistant disc 5 is a disc structure with a through hole coaxially opened in the center. The size of the through hole is larger than the diameter of the main shaft. The wear-resistant disc 5 is coaxially installed on the bottom of the countersunk platform of the swashplate 4 through a positioning pin, providing a stable sliding surface for the plunger assembly 6.

[0030] like Figure 5As shown, the return disk 13 is a disc structure with a through hole coaxially formed at its center. The size of this through hole is the same as the size of the through hole formed on the wear-resistant disk 5. Multiple mounting holes are also evenly formed around the outer periphery of the through hole on the return disk for mounting the plunger assembly 6.

[0031] There are multiple plunger assemblies 6, the number of which matches the number of mounting holes on the return plate 13. Each plunger assembly 6 consists of a plunger and a slipper. One end of the slipper is flat, and the other end is concave to accommodate the plunger. The plunger and slipper are hinged together, allowing the plunger to rotate freely. The plunger is arranged parallel to the cavity inside the cylinder body (i.e., its axis is parallel to the cylinder body axis). The concave end of the slipper passes through the mounting hole of the return plate 13, and the flat end is located between the return plate 13 and the wear-resistant plate 5 and connects with both.

[0032] The pressure plate 11 is fixed to the step of the swash plate 4 with screws, and an adjusting shim 12 is installed between the pressure plate 11 and the swash plate 4, also fixed with screws. Figure 6 As shown, the adjusting pad 12 has a ring-shaped structure with through holes distributed along the ring. The number, size, and position of the through holes correspond one-to-one with the threaded holes on the swash plate 4. The inner diameter of the adjusting pad 12 is slightly larger than the outer diameter of the return plate 13 to prevent friction and interference between the return plate 13 and the adjusting pad 12 during the movement, and also to avoid wear on the adjusting pad 12.

[0033] like Figure 7 As shown, the pressure plate 11 has a ring-shaped structure, with through holes distributed along the ring. The number, size, and position of these through holes correspond one-to-one with the through holes on the adjusting shim 12. The inner diameter of the pressure plate 11 is smaller than the outer diameter of the return plate 13, thus providing axial constraint on the return plate 13. This embodiment also includes a lubrication design: the side of the pressure plate 11 that contacts the return plate 13 has several oil guide grooves evenly distributed along the circumference to store oil. During normal pump operation, the oil enters the gap between the return plate 13 and the pressure plate 11 through the oil guide grooves, forming an oil film that provides lubrication and reduces wear. Evenly distributed oil guide grooves ensure uniform lubrication, improve the load-bearing capacity of the oil film, and facilitate heat dissipation; uneven distribution can cause uneven load, uneven wear, and abnormal wear.

[0034] When the hydraulic pump is working, due to the adjusting shim 12 installed between the pressure plate 11 and the swash plate 4, there is a very small axial clearance between the return plate 13 and the pressure plate 11. When the pump draws oil, the main shaft 3 drives the cylinder 9 to rotate, and the plunger assembly 6 extends outward under the pulling force of the return plate 13. At this time, the return plate 13 and the pressure plate 11 are theoretically in contact on the pump's suction side. At the same time, because the pressure plate 11 has an oil guide groove, a discontinuous oil film can be formed between the rotating return plate 13 and the pressure plate 11. Due to the presence of the oil film, the return plate 13 and the pressure plate 11 are not in direct contact. They contact where the oil film is discontinuous, and interact with each other through the oil film where it is continuous. Therefore, the return plate 13 and the pressure plate 11 exhibit a floating state of intermittent contact, that is, the return plate 13 and the pressure plate 11 float in contact during movement. During assembly, adjusters of different thicknesses of shims 12 are selected based on actual measurements to control the axial clearance between the pressure plate 11 and the return plate 13.

[0035] This invention uses a floating limit return plate 13 of pressure plate 11 to constrain return plate 13. At the same time, an adjusting shim 12 is installed between pressure plate 11 and swash plate 4. The thickness of the adjusting shim 12 is selected according to the actual machining size of the part. Meanwhile, the side of pressure plate 11 that contacts return plate 13 has several oil guide grooves along the circumferential direction to store oil. Return plate 13 and pressure plate 11 float in contact. When the pump is working normally, an oil film can be formed between them.

[0036] The main shaft 3 is connected to the aircraft engine via a coupling sleeve. The main shaft 3 drives the cylinder block 9, the plunger assembly 6, and the return plate 13 to rotate together. Because the swashplate 4 has an angle relative to the main shaft 3, the plungers of the plunger assembly 6 reciprocate axially under the constraint of the return plate 13 as they rotate with the cylinder block 9. Specifically, when the plunger extends along the cylinder block 9, the pressure plate 11 contacts the return plate 13, causing the plunger to draw in oil; when the plunger retracts, the oil is discharged. Multiple plungers operate periodically, and the pump continuously achieves oil suction and discharge.

[0037] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. An aviation plunger pump with a floating return mechanism, characterized in that, include: The assembly includes a mounting base, housing, cylinder, spindle, swash plate, swash plate bearing, plunger assembly, and wear-resistant disc, return disc, adjusting shim, and pressure plate arranged coaxially from front to back. The rear end face of the mounting base is sealed to the front end face of the housing, and a communicating cavity is formed inside the mounting base and the housing. The cylinder is installed in the cavity inside the housing, and the spindle passes through a through hole coaxially formed in the center of the cylinder and is fixedly connected to it. The spindle is rotatably mounted on the mounting base and housing via bearings and is fixedly connected to an external power unit. The swash plate is a flat cylinder with two stepped countersunk holes coaxially formed on its front face. The first-stage countersunk hole starts from the front face, and the second-stage countersunk hole starts from the bottom face of the first-stage countersunk hole, with a smaller diameter than the first-stage countersunk hole. A through hole is coaxially formed in the center of the second-stage countersunk hole for the spindle to pass through. The recessed structure formed by the second-stage countersunk hole is called the countersunk platform, and the annular platform between the two countersunk holes is called the step. Shafts are fixed to both radial ends of the swash plate and are respectively interference-fitted onto the inner ring of the swash plate bearing, which is arranged on a mounting base. The wear-resistant disc is coaxially mounted on the bottom of the countersunk platform. The plunger assembly includes a plunger and a slipper. One end of the slipper is flat and is located between and in contact with the return plate and the wear plate. The other end is concave and passes through the mounting hole of the return plate to receive and hinge the plunger head. The plunger is arranged parallel to the cavity inside the cylinder body. The pressure plate is fixedly installed on the step and has a ring structure with an inner diameter smaller than the outer diameter of the return plate, which is used to axially constrain the return plate; the adjusting pad is arranged between the pressure plate and the swash plate and has a ring structure with an inner diameter larger than the outer diameter of the return plate; several oil guide grooves are evenly opened circumferentially on the side of the pressure plate that contacts the return plate.

2. The aviation plunger pump with a floating return mechanism according to claim 1, characterized in that, The wear-resistant disc is a disc structure with a through hole coaxially opened in the center. The size of the through hole is the same as the size of the through hole opened in the center of the swash plate. The wear-resistant disc is coaxially installed on the bottom of the swash plate's countersunk platform by a positioning pin.

3. The aviation plunger pump with a floating return mechanism according to claim 1, characterized in that, The return plate is a disc structure with a through hole coaxially formed at the center for the main shaft to pass through; multiple mounting holes are also uniformly formed around the outer periphery of the through hole of the return plate for mounting the plunger assembly.

4. The aviation plunger pump with a floating return mechanism according to claim 1, characterized in that, The pressure plate and adjusting pad are fixedly installed on the step of the swash plate by threaded connection.

5. The aviation plunger pump with a floating return mechanism according to claim 1, characterized in that, It also includes a front bearing and a rear bearing; the front bearing, the main shaft, and the rear bearing are arranged coaxially in sequence, the front bearing is fixed to the mounting base, and the rear bearing is fixed to the housing; one end of the main shaft is mounted on the inner ring of the front bearing, and the other end is mounted on the inner ring of the rear bearing.

6. The aviation plunger pump with a floating return mechanism according to claim 1, characterized in that, The main shaft and the cylinder are fixedly connected by a spline pair, wherein the main shaft has an external spline and the cylinder has an internal spline that mates with the main shaft in the central through hole.

Images