A sliding shoe plunger assembly gap setting return device

Abstract

The present application belongs to the technical field of aero-engine fuel / oil system, and relates to a sliding shoe plunger assembly fixed-gap return device. A swash plate is attached to one side end surface of a middle plate, a retainer is arranged outside the middle plate and is clamped to the middle plate, a sliding shoe plunger assembly is arranged in a mounting hole correspondingly, there is a gap Δs between the working end surface of the sliding shoe plunger assembly and the other side end surface of the middle plate, a middle small hole in the sliding shoe plunger assembly and an oil passage small hole on the middle plate are in one-to-one correspondence and are in communication, a check ring is arranged in the retainer and is located outside the middle plate, the outer surface of a supporting ball is a spherical surface, the supporting ball is arranged in the shaft hole in the middle plate and is in spherical hinge cooperation with the shaft hole in the middle plate, and can rotate in any direction of the shaft hole, one end of a rotating shaft passes through the shaft hole of the retainer, the shaft hole of the supporting ball, the shaft hole of the middle plate and the check ring in sequence, and is connected with the swash plate, the other end of the rotating shaft is connected with a shell, a central spring is sleeved on the shaft, one end of the central spring is in contact with the end surface of the supporting ball, and the other end of the central spring applies pressure through the shell.

Description

Technical Field

[0001] This invention belongs to the technical field of aero-engine fuel / lubricating oil systems and relates to a slipper plunger assembly with a fixed clearance return device, which is suitable for slipper plunger pumps, especially plunger pumps for aviation fuel or hydraulic oil media with high speed, high pressure and long service life requirements. Background Technology

[0002] The plunger pump is one of the most important accessories in the fuel / lubricating oil system of an aero-engine. It has the function of infinitely variable adjustment and has the most obvious advantages in systems with strict thermal management requirements. As the service life of the plunger pump in the engine system has been increased from 300 hours for straight plungers to 750 hours, and even reached 1000 hours, straight plungers can no longer meet the service life requirements. Therefore, the development direction of new products has gradually shifted to slipper-type plunger pumps.

[0003] The slipper assembly is one of the most important components of a slipper-type piston pump. The traditional design involves designing an oil sump on the slipper end face, and introducing high-pressure fuel into the piston chamber to form an oil film field with pressure distribution between the slipper and the swashplate. The slipper and the swashplate rotate at relatively high speeds, and the specific power PV is generally high. Therefore, the design requires high standards for the slipper and swashplate mating friction pair and the formation of a stable oil film.

[0004] Traditional slipper assemblies often experience failures during use, such as slipper end face wear, cavitation, and adhesive wear between the two friction surfaces. These issues prevent the slipper and swashplate from forming a stable oil film, leading to rapid failure. The solution is to replace the entire slipper plunger assembly or a slipper plunger assembly with a rotor. However, the manufacturing process for slipper plunger assemblies or rotor-equipped slipper plunger assemblies is extremely complex, resulting in long repair or overhaul cycles and high production costs for failed products.

[0005] Analysis shows that without changing the working method of the transmission slipper, the wear and replacement of the slipper will always be a problem. Therefore, in order to improve the service life of the slipper plunger assembly and reduce the maintenance or overhaul cost of the plunger pump, it is necessary to propose a slipper plunger assembly constant clearance return device for transferring the friction pair. Summary of the Invention

[0006] The purpose of this invention is to provide a constant clearance return device for a slipper plunger assembly, which can improve the service life of the slipper plunger assembly and reduce the maintenance or overhaul cost of the plunger pump.

[0007] Technical solution of the present invention

[0008] A constant clearance return device for a slipper plunger assembly includes a swashplate 1, a slipper plunger assembly 5, and a rotating shaft, as well as an intermediate plate 2, a retaining ring 3, a cage 4, a support ball 6, and a central spring 7;

[0009] Among them: the inclined plate 1 is attached to one end face of the middle plate 2. Several waist-shaped oil pools are provided on the side end face of the middle plate 2 that is attached to the inclined plate 1. The waist-shaped oil pools are provided with small oil passages that pass through the middle plate 2. Each pair of adjacent waist-shaped oil pools are connected by an oil groove between the pools. Several arc-shaped shoulders are evenly distributed on the outer cylindrical surface of the middle plate 2.

[0010] The retainer 4 is set outside the intermediate plate 2 and snapped into the intermediate plate 2. The retainer 4 is provided with a number of mounting holes evenly distributed along the axial hole at its center. The number of mounting holes is the same as the number of oil passage holes on the intermediate plate 2. The number of slipper plunger assemblies 5 matches the number of mounting holes and is respectively set in the mounting holes. The working end face of all slipper plunger assemblies 5 is located on the other side of the intermediate plate 2 and there is a gap △s between them and the other end face of the intermediate plate 2. The central hole inside the slipper plunger assembly 5 corresponds to the position of the oil passage hole on the intermediate plate 2 and is connected one by one.

[0011] The retaining ring 3 is disposed inside the retainer 4, and the retaining ring 3 is located outside the middle plate 2;

[0012] The outer surface of the support ball 6 is spherical. The support ball 6 is set in the shaft hole in the middle of the intermediate plate 2 and is ball-jointed with the shaft hole of the intermediate plate, so that it can rotate in any direction of the shaft hole.

[0013] One end of the rotating shaft passes through the shaft hole of the retainer 4, the shaft hole of the support ball 6, the shaft hole of the intermediate plate 2, and the retaining ring 3 in sequence and is connected to the swashplate. The other end of the rotating shaft is connected to the housing. The central spring 7 is sleeved on the shaft, with one end in contact with the end face of the support ball 6 and the other end applying pressure through the housing.

[0014] Furthermore, on the side end face where the intermediate plate 2 is attached to the inclined plate 1, there are Z waist-shaped oil pools evenly distributed along the axial holes at their centers. The depth of the waist-shaped oil pool is ΔL, the diameter of the small oil passage hole penetrating the intermediate plate 2 in the waist-shaped oil pool is d, and the depth of the oil groove between the pools is less than the depth ΔL of the waist-shaped oil pool.

[0015] Furthermore, a friction-reducing material layer or coating is inlaid on the side end face of the intermediate plate 2 that is in contact with the inclined plate 1.

[0016] Furthermore, the inlaid anti-friction material layer or coating is a tin-lead bronze layer.

[0017] Furthermore, the outer circumferential surface of the intermediate plate 2 is uniformly provided with arc-shaped shoulders or involute external splines, and the circumferential angle between the arc-shaped shoulders or involute external splines and the oil passage hole is 180° / Z.

[0018] Furthermore, the cage 4 is provided with Z evenly distributed sliding shoe assembly plunger mounting holes, the diameter of which is larger than the outer diameter of the sliding shoe plunger assembly 5.

[0019] Furthermore, the inner wall of the retainer 4 is provided with a retaining ring mounting groove, an inner groove, and an outer groove along its circumference. The inner groove and the outer groove are respectively located on both sides of the retaining ring mounting groove, and the inner groove is close to the plunger mounting hole of the slipper assembly of the retainer 4. Z outer arc or involute inner splines are evenly distributed on the circumference of the inner groove and the outer groove, and the outer arc or involute inner splines on the inner groove and the outer groove are staggered. The included angle between the outer arc or involute inner spline on the inner groove and the outer arc or involute inner spline on the adjacent outer groove is 180° / Z.

[0020] Furthermore, the intermediate plate 2 is disposed in the inner groove of the inner retainer 4, and is engaged with the outer arc or involute spline on the outer circumferential surface of the intermediate plate 2 through the arc-shaped shoulder or involute spline on the inner groove; the outer arc or involute spline on the outer groove also matches the arc-shaped shoulder or involute spline on the outer circumferential surface of the intermediate plate 2; the retaining ring 3 is installed in the retaining ring mounting groove of the retainer to prevent the intermediate plate 2 from coming out of the retainer 4.

[0021] Furthermore, the outer arc or involute spline position on the inner groove is located on the centerline of the plunger mounting holes of two adjacent slipper assemblies; the outer arc or involute spline position on the outer groove corresponds one-to-one with the position of the plunger mounting hole of the slipper assembly.

[0022] Furthermore, the retainer 4 has an overtravel groove on the inner side of the end face of the plunger mounting hole of the slipper assembly; the outer circumferential surface of the retainer 4 has a rectangular observation window, which is correspondingly set in the circumferential angle direction of the plunger mounting hole of the slipper assembly.

[0023] The beneficial effects of this invention are:

[0024] 1) The cage 4 is designed with the same number of slipper assembly plunger mounting holes as the plunger. The size of the slipper assembly plunger mounting holes is larger than the outer wall surface of the slipper plunger assembly 5. The end face of the slipper assembly with the plunger mounting holes on the cage 4 can be flat ground by special grinding equipment to keep the flatness ≤0.005.

[0025] 2) A rectangular observation window is set on the outer wall corresponding to the plunger mounting hole of the cage 4 slipper assembly. The gap between the intermediate plate and the slipper can be detected through the window. The length of the window is equal to the maximum outer diameter of the slipper sealing strip.

[0026] 3) The inner and outer grooves of the retainer 4 are provided with stepped misaligned outer arcs or involute inner splines. The outer arcs or involute inner splines on the inner grooves cooperate with the outer circumferential arc-shaped shoulder or involute outer splines of the intermediate plate 2 to prevent radial rotation of both. A retainer mounting groove is provided between the inner and outer grooves for installing retainer rings.

[0027] 4) The flatness and parallelism of both sides of the intermediate plate 2 are ≤0.005. The surface corresponding to the slipper plunger assembly is a complete plane. A waist-shaped or circular oil pool is provided on the surface in contact with the swashplate. There is a small oil passage hole at the bottom of the oil pool, and oil is directly supplied by the small hole in the middle of the slipper plunger assembly 5. An inter-pool oil groove is provided between the waist-shaped or circular oil pools. The depth of the oil groove is ≤ the depth of the oil pool, and the width is 0.5 mm to 1 mm.

[0028] 5) During assembly, the thickness S of the intermediate plate 2 is selected to ensure that the gap Δs between the working end face of the slipper plunger assembly 5 and the intermediate plate 2 is 0 to 0.005 mm; to ensure that the slipper plunger assembly 5 and the intermediate plate 2 can move freely and seal the working medium.

[0029] 6) The outer arc or involute spline on the inner groove of the retainer 4 maintains a specific relative angle with the plunger mounting hole of the slipper assembly, i.e., 180° / z. At the same time, the arc-shaped shoulder or involute spline on the outer circumference of the intermediate plate 2 maintains the same relative angle with the center of the waist-shaped oil sump; ensuring that the oil sump of the slipper assembly can pass through the corresponding small hole in the intermediate plate when any installation is performed.

[0030] 7) Wear-resistant materials or coatings are inlaid on the mating surfaces of the middle plate 2 and the inclined plate 1 to improve their service life. Attached Figure Description

[0031] Figure 1 This is an exploded view of the device assembly of the present invention;

[0032] Figure 2 This is a cross-sectional view of the device assembly of the present invention;

[0033] Figure 3 This is a schematic diagram of the device of the present invention assembled in the product;

[0034] Figure 4 This is a rear view of the intermediate plate of the device of the present invention;

[0035] Figure 5 This is a side view of the middle plate of the device of the present invention;

[0036] Figure 6 This is a front view of the intermediate plate of the device of the present invention;

[0037] Figure 7 This is a structural diagram of the retainer of the device of the present invention;

[0038] Figure 8 This is a schematic diagram of the internal groove of the holder of the device of the present invention;

[0039] Figure 9 This is a side view of the retainer of the device of the present invention;

[0040] Figure 10 yes Figure 9 A cross-sectional view along the AA direction.

[0041] In the picture:

[0042] 1-Swashplate, 2-Intermediate plate, 3-Retaining ring, 4-Cage, 5-Slipper plunger assembly, 6-Support ball, 7-Center spring. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0044] like Figure 1-10 The invention shown is a fixed-clearance return device for a slipper plunger assembly. Its assembly explosion relation on the product is shown in [reference needed]. Figure 1 and 3 As shown, the assembly section view Figure 2 As shown, the assembly mainly includes an intermediate plate 2, a retaining ring 3, a retainer 4, a support ball 6, and a central spring 7. It also includes Z slipper plunger assemblies 5, each suspended in a corresponding mounting hole in the retainer 4. The intermediate plate 2 is mounted from the left, abutting against the left working end face of the slipper plunger assembly 5. The retaining ring 3 is inserted into the retaining ring mounting groove of the retainer 4 to prevent the intermediate plate 2 from dislodging. During assembly, intermediate plates 2 of different thicknesses S must be selected to maintain a certain gap Δs between the intermediate plate 2 and the slipper plunger assembly 5, ensuring that the slipper can slide freely between the retainer 4 and the intermediate plate 2. The support ball 6 and the intermediate plate 2 are ball-jointed, allowing flexible rotation in any direction. Under the preload of the central spring, they remain abutting against each other. When the swashplate 1 and the right side of the central spring 7 are fixed in the direction of the plunger pump shaft center, the intermediate plate 2 is pressed tightly against the swashplate 1.

[0045] The structure of intermediate plate 2 is shown below. Figure 4-6 The plate has two flat surfaces with high flatness and parallelism on both sides. Between these surfaces are Z evenly distributed oil passage holes with a diameter of d. The end face that works in contact with the swashplate 1 has Z evenly distributed waist-shaped oil sumps with a depth of ΔL. Oil grooves with a depth ≤ΔL are provided between the oil sumps to allow for normal fuel flow. The oil passage holes are located in the center of the oil sumps. To ensure wear resistance on the sides of the oil sumps, anti-friction materials or coatings are usually inlaid on these surfaces. The outer circular shaft of the intermediate plate 2 has an arc-shaped shoulder or an involute external spline, with the shoulder or spline forming a circumferential angle of 180° / Z with the oil passage holes.

[0046] See cage 4 structure Figure 7-10The swashplate 4 has Z evenly distributed sliding plunger assembly mounting holes, the diameter of which is larger than the outer diameter of the sliding plunger assembly 5, ensuring no interference between them within the tilt angle range of the swashplate operation. The end face of the sliding plunger assembly mounting hole is a complete plane, and an overrun groove is provided on the inner side of this end face to ensure the flatness of the machined surface. A clearance observation window of a certain width and height is provided in the circumferential angle direction corresponding to the sliding plunger assembly mounting hole to observe and detect the assembly clearance △s between the sliding plunger assembly 5 and the intermediate plate 2. A retaining ring mounting groove is provided on the inner circumferential wall of the retaining ring 4. An inner groove and an outer groove are respectively provided on both sides of the retaining ring mounting groove. Z outer arcs or involute inner splines are provided on the circumference of the inner and outer grooves. The outer arcs or involute inner splines on the inner groove are located at the midpoint of the circumferential angle between two adjacent mounting holes, and the circumferential angle between the inner and outer grooves is 180° / Z.

[0047] See Figure 2 When the plunger pump is working, the rotor drives the slipper plunger assembly 5 to rotate, which in turn drives the cage 4 to rotate. Since the cage 4 and the intermediate plate 2 are circumferentially fixed by the arc-shaped shoulder groove / involute spline, the intermediate plate 2, retaining ring 3, cage 4, slipper plunger assembly 5, support ball 6 and central spring 7 rotate without slip. At this time, there is no obvious sliding between the slipper plunger assembly 5 and the intermediate plate 2. The rotational friction mainly occurs on the contact surface between the swashplate 1 and the intermediate plate 2. Through the small hole in the middle of the slipper plunger assembly 5 and the small oil passage in the intermediate plate 2, the high-pressure oil in the plunger cavity of the slipper plunger assembly 5 enters the oil sump of the intermediate plate 2, which plays the role of lubrication and counteracting the plunger oil pressure. As the angle of the swashplate 1 changes, the support ball 6 rotates at the corresponding angle in the shaft hole of the intermediate plate 2. The fixed clearance Δs return device, composed of the intermediate plate 2, retaining ring 3, retainer 4, support ball 6 and central spring 7, rotates at the same angle as the support ball 6, always keeping the friction surface of the intermediate plate 2 in contact with the swashplate 1. Under the support of this device, the slipper plunger assembly 5 realizes oil suction and oil pressure.

[0048] See Figure 2-3Compared to the traditional slipper plunger assembly structure, this device uses a central spring for concentrated force return instead of a single plunger and single spring return method. The working principle of this device is as follows: When the oil pump's oil supply needs adjustment, the swashplate 1 rotates under the action of the external structure, while the intermediate plate 2, carrying the retaining ring 3 and the cage 4, rotates simultaneously around the support ball 6. In the low-pressure area corresponding to the oil pump distributor plate, the slipper plunger assembly 5 is forcibly pulled out of the rotor plunger hole under the push of the cage. During the pulling process, the slipper plunger assembly 5 and the cage 4 remain pressed together, with a gap of Δs between it and the intermediate plate 2, ensuring strict control of leakage. In the high-pressure area corresponding to the oil pump distributor plate, the slipper plunger assembly 5 is pressed into the rotor plunger hole by the pushing force of the swashplate 1 and the intermediate plate 2. During the pressing process, the slipper plunger assembly 5 and the intermediate plate 2 remain pressed together, with a gap of Δs between it and the cage 4, ensuring strict control of the slipper's overturning amount between the intermediate plate 2 and the cage 4. In addition, in the high-pressure and low-pressure conversion area corresponding to the oil distributor, the gap Δs can ensure the flexibility of the slipper's rotation and impact.

[0049] Since the friction between the slipper plunger assembly 5 and the intermediate plate 2 in this invention is mainly slight sliding friction (caused by the change in the center trajectory due to the rotation of the slipper plunger assembly 5 and the change in the angle of the swashplate 1), the working surface of the slipper plunger assembly is well protected. The main function of the entire device is to transfer the friction between the slipper plunger assembly 5 and the swashplate 1 to the friction between the intermediate plate 2 and the swashplate 1. Since the contact area between the intermediate plate 2 and the swashplate 1 is relatively large compared to the original slipper oil sump seal, the specific work PV of the friction pair can be reduced to a large extent, thus improving the service life. When the plunger pump is overhauled or repaired, only the worn intermediate plate 2 needs to be replaced, which greatly shortens the maintenance cycle and reduces costs.

[0050] The main technical features of this invention are:

[0051] 1) The cage 4 is designed with the same number of slipper assembly plunger mounting holes as the plunger. The size of the slipper assembly plunger mounting holes is larger than the outer wall surface of the slipper plunger assembly 5. The end face of the slipper assembly with the plunger mounting holes on the cage 4 can be flat ground by special grinding equipment to keep the flatness ≤0.005.

[0052] 2) A rectangular observation window is set on the outer wall corresponding to the plunger mounting hole of the cage 4 slipper assembly. The gap between the intermediate plate and the slipper can be detected through the window. The length of the window is equal to the maximum outer diameter of the slipper sealing strip.

[0053] 3) The inner and outer grooves of the retainer 4 are provided with stepped misaligned outer arcs or involute inner splines. The outer arcs or involute inner splines on the inner grooves cooperate with the outer circumferential arc-shaped shoulder or involute outer splines of the intermediate plate 2 to prevent radial rotation of both. A retainer mounting groove is provided between the inner and outer grooves for installing retainer rings.

[0054] 4) The flatness and parallelism of both sides of the intermediate plate 2 are ≤0.005. The surface corresponding to the slipper plunger assembly is a complete plane. A waist-shaped or circular oil pool is provided on the surface in contact with the swashplate. There is a small oil passage hole at the bottom of the oil pool, and oil is directly supplied by the small hole in the middle of the slipper plunger assembly 5. An inter-pool oil groove is provided between the waist-shaped or circular oil pools. The depth of the oil groove is ≤ the depth of the oil pool, and the width is 0.5 mm to 1 mm.

[0055] 5) During assembly, the thickness S of the intermediate plate 2 is selected to ensure that the gap Δs between the working end face of the slipper plunger assembly 5 and the intermediate plate 2 is 0 to 0.005 mm; to ensure that the slipper plunger assembly 5 and the intermediate plate 2 can move freely and seal the working medium.

[0056] 6) The outer arc or involute spline on the inner groove of the retainer 4 maintains a specific relative angle with the plunger mounting hole of the slipper assembly, i.e., 180° / z. At the same time, the arc-shaped shoulder or involute spline on the outer circumference of the intermediate plate 2 maintains the same relative angle with the center of the waist-shaped oil sump; ensuring that the oil sump of the slipper assembly can pass through the corresponding small hole in the intermediate plate when any installation is performed.

[0057] 7) Wear-resistant materials or coatings are inlaid on the mating surfaces of the middle plate 2 and the inclined plate 1 to improve their service life.

[0058] One embodiment of the present invention is as follows:

[0059] Before assembly, according to Figure 4-6 The intermediate plate 2 is machined with a 40° included angle between the centers of the waist-shaped oil sumps. Nine arc-shaped shoulders are evenly distributed on the outer cylindrical surface of the intermediate plate 2. The arc height of the arc-shaped shoulders is not greater than the width of the retainer ring mounting groove of the cage 4. The included angle between the oil passage hole and the center of the arc-shaped shoulder is 20°. The waist-shaped oil sump is 1mm deep, and the oil groove between the sumps is 1mm wide and 0.5mm deep. The diameter of the oil passage hole is the same as that of the small hole in the middle of the slipper plunger assembly 5, which is 0.8mm. The parallelism of the two sides of the intermediate plate 2 is required to be 0.005mm. The intermediate plate 2 is made of structural steel, and tin-lead bronze with a thickness of 1-1.5mm is inlaid on the side of the waist-shaped oil sump as a grinding material. The thickness of the intermediate plate 2 is distinguished by a thickness difference of 0.005.

[0060] Before assembly, according to Figure 7-10 The cage 4 is machined such that the included angle between the centers of adjacent outer arcs on the inner groove circumference is 40°, and the included angle between the centers of adjacent outer arcs on the outer groove circumference is also 40°. The included angle between two adjacent outer arcs on the inner and outer groove circumferences is 20°. The size of the observation window is 24mm × 5mm. The size of the mounting hole for the slipper plunger assembly is 2mm larger than the outer diameter of the slipper plunger assembly 5. The flatness of the end face of the mounting hole for the slipper plunger assembly on the cage 4 is 0.005mm, and the roughness is Ra0.4. The fit between the outer diameter of the intermediate plate 2 and the inner hole of the cage 4 is H8 / f7.

[0061] Before assembly, the installation height difference of the nine optional slipper plunger assemblies 5 shall not exceed 0.005mm.

[0062] During assembly, the slipper plunger assemblies 5 are respectively installed into the slipper plunger assembly mounting holes of the retainer 4. The arc-shaped shoulder of the intermediate plate 2, corresponding to the outer arc on the outer groove of the retainer 4, is first installed into the retainer ring mounting groove. The intermediate plate 2 is then rotated 20° and installed into the inner groove of the retainer 4, with the arc-shaped shoulder on the intermediate plate engaging with the outer arc on the circumference of the inner groove. At this time, the thickness of the intermediate plate 2 should be one piece with the minimum thickness. The retainer ring 3 is installed on the outside of the intermediate plate 2, located in the retainer ring mounting groove. The gap Δs between the working end face of the nine slipper plunger assemblies 5 and the intermediate plate 2 is measured through the rectangular observation window using a feeler gauge. If the gap Δs exceeds 0.01mm, the intermediate plate 2 of the thicker group is replaced to ensure that Δs meets the requirement of 0~0.01mm.

[0063] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A sliding shoe plunger assembly lash return device comprising a swash plate (1), a sliding shoe plunger assembly (5) and a rotation axis, characterized in that, It also includes intermediate plate (2), baffle ring (3), cage (4), support ball (6) and center spring (7); Wherein: the swash plate (1) is attached to the one side end surface of the intermediate plate (2), the intermediate plate (2) is provided with a plurality of oil pools which are evenly distributed along the axial hole at the center of the intermediate plate (2) on the side end surface attached to the swash plate (1), the oil pools are provided with through oil holes which penetrate the intermediate plate (2), every two adjacent oil pools are connected by an inter-pool oil groove, a plurality of arc-shaped shoulders are evenly distributed on the outer cylindrical surface of the intermediate plate (2); The cage (4) is arranged outside the intermediate plate (2) and is clamped with the intermediate plate (2), a plurality of mounting holes which are evenly distributed along the axial hole at the center of the cage (4) are arranged on the cage (4), the number of the mounting holes is the same as the number of the through oil holes on the intermediate plate (2), the number of the shoe plunger assemblies (5) is matched with the number of the mounting holes, and the shoe plunger assemblies (5) are respectively arranged in the mounting holes, the working end surfaces of all the shoe plunger assemblies (5) are located on the other side of the intermediate plate (2) and have a gap Δs with the other side end surface of the intermediate plate (2), the intermediate holes in the shoe plunger assemblies (5) are one-to-one corresponding with the through oil holes on the intermediate plate (2); The baffle ring (3) is arranged in the cage (4) and is located outside the intermediate plate (2); The outer surface of the support ball (6) is spherical, the support ball (6) is arranged in the axial hole at the center of the intermediate plate (2) and is ball-hinged with the axial hole of the intermediate plate (2), so that the support ball (6) can rotate in any direction of the axial hole; One end of the rotating shaft is sequentially arranged through the axial hole of the cage (4), the axial hole of the support ball (6), the axial hole of the intermediate plate (2), the baffle ring (3) and the swash plate (1), the other end of the rotating shaft is connected with the shell, the center spring (7) is sleeved on the shaft, one end of the center spring (7) is in contact with the end surface of the support ball (6), and the other end of the center spring (7) applies pressure through the shell; Z mounting holes of the shoe assembly plunger are evenly distributed on the cage (4), the hole diameter of the mounting holes is larger than the outer diameter of the shoe plunger assembly (5); the inner wall of the cage (4) is provided with a baffle ring mounting groove and an inner groove and an outer groove in the circumferential direction of the cage (4), the inner groove and the outer groove are respectively arranged on the two sides of the baffle ring mounting groove, and the inner groove is close to the mounting hole of the shoe assembly plunger of the cage (4); Z outer circular arcs or involute inner splines are evenly distributed on the circumferences of the inner groove and the outer groove, the outer circular arcs or involute inner splines on the inner groove and the outer groove are arranged in a staggered manner, and the included angle between the outer circular arcs or involute inner splines on the inner groove and the outer circular arcs or involute inner splines on the adjacent outer groove is 180° / Z.

2. A sliding shoe plunger assembly constant clearance return device according to claim 1 wherein, Z waist-shaped oil pools or circular oil pools which are evenly distributed along the axial hole at the center of the intermediate plate (2) are arranged on the side end surface of the intermediate plate (2) attached to the swash plate (1), the depth of the waist-shaped oil pool or the circular oil pool is ΔL, the diameter of the through oil hole which penetrates the intermediate plate (2) in the waist-shaped oil pool or the circular oil pool is d, and the depth of the inter-pool oil groove is less than the depth ΔL of the waist-shaped oil pool.

3. A sliding shoe plunger assembly constant clearance return device according to claim 2, wherein, A layer of embedded wear-reducing material or a coating is inlaid on the side end surface of the intermediate plate (2) attached to the swash plate (1).

4. A sliding shoe plunger assembly constant clearance return device as claimed in claim 3, wherein, The layer of embedded wear-reducing material or the coating is a tin-lead bronze layer.

5. A sliding shoe plunger assembly constant clearance return device as claimed in claim 4, wherein, The intermediate plate (2) is uniformly provided with a circular-arc shoulder or an involute outer spline on the outer circumferential surface, and the circumferential included angle between the circular-arc shoulder or the involute outer spline and the oil passage hole is 180° / Z.

6. A sliding shoe plunger assembly constant clearance return device as claimed in claim 5, wherein, The intermediate plate (2) is arranged in the inner groove of the inner retainer (4) and is clamped and connected with the outer circular arc or the involute inner spline on the outer groove through the circular-arc shoulder or the involute outer spline on the outer circumferential surface of the intermediate plate (2); the outer circular arc or the involute inner spline on the outer groove is also matched with the circular-arc shoulder or the involute outer spline on the outer circumferential surface of the intermediate plate (2); the check ring (3) is arranged in the check ring mounting groove of the retainer, so as to prevent the intermediate plate (2) from being separated from the retainer (4).

7. A sliding shoe plunger assembly constant clearance return device as claimed in claim 6, wherein, The position of the outer circular arc or the involute inner spline on the inner groove is located on the center line of the two adjacent sliding shoe assembly plunger mounting holes; the position of the outer circular arc or the involute inner spline on the outer groove is one-to-one corresponding to the position of the sliding shoe assembly plunger mounting hole.

8. A sliding shoe plunger assembly constant clearance return device as claimed in claim 1, wherein, The end surface of the retainer (4) arranged with the sliding shoe assembly plunger mounting hole is provided with an overtravel groove; the outer circumferential surface of the retainer (4) is provided with a rectangular observation window, which is arranged in the circumferential angle direction corresponding to the sliding shoe assembly plunger mounting hole.

Images