Piston shoe assembly of hydraulic pump plunger of excavator

Abstract

The utility model relates to the technical field of plunger pumps, in particular to an excavator hydraulic pump plunger piston shoe assembly which comprises a plunger and a piston shoe, a one-way oil outlet pipe is arranged in an oil outlet hole and is of a circular tube structure with one open end and one closed end, the open end of the one-way oil outlet pipe faces an expansion groove, and the piston shoe is arranged in the expansion groove. The side wall, close to the closed end, of the sliding shoe is provided with a plurality of oil discharging parts which are evenly arranged in the circumferential direction. During oil pumping, under the action of pressure, the one-way oil outlet pipe is in an open state, and oil in the oil outlet pipe can be input into the inner oil storage tank through the oil discharge part; when the plunger is in an oil suction state, under the action of negative pressure, the one-way oil outlet pipe slides towards one side of the plunger, the oil discharge part is closed after moving into the oil outlet hole, the one-way oil outlet pipe is in a closed state, oil in the inner oil storage tank cannot be sucked back to the cylinder body by the negative pressure, and sufficient oil can be maintained in the inner oil storage tank for lubrication.

Description

Technical Field

[0001] The utility model relates to the technical field of plunger pumps, and more specifically to a plunger and slipper assembly of an excavator hydraulic pump. Background Art

[0002] Almost all the actions of an excavator are driven by a hydraulic system, and the core component of the hydraulic system is a hydraulic plunger pump, which provides sufficient oil pressure for the entire hydraulic system. The hydraulic motor that drives the excavator to move forward and the hydraulic cylinder that drives the excavating arm to move are all powered by the hydraulic plunger pump, and the hydraulic plunger pump is driven by the diesel engine of the excavator.

[0003] Axial plunger pumps are used in excavators, which have the advantages of simple structure, small size, low noise, high efficiency, long service life, and self-priming ability. The plunger is connected to a swash plate inclined at a certain angle through a slipper. As the cylinder block rotates, the plunger reciprocates to perform the functions of oil suction and pumping.

[0004] During the rotation of the cylinder block, the slipper will rub against the swash plate. To reduce wear, corresponding oil grooves are provided on the friction surface of the slipper, and pipelines for delivering oil to the oil grooves are provided on the plunger and the slipper. When the plunger is in the pumping state, under the action of pressure, the oil fluid enters the oil grooves on the friction surface of the slipper through the pipeline, and an oil film is generated between the slipper and the swash plate to play a lubricating role. However, during the oil suction process of the plunger, the pressure in the oil delivery pipeline decreases or even generates negative pressure, and the oil fluid in the oil grooves on the friction surface of the slipper will be sucked into the cylinder block, resulting in insufficient lubrication between the slipper and the swash plate and increased wear. Summary of the Utility Model

[0005] In view of the technical problems of the slipper in the prior art, the first aspect of the present utility model provides a plunger and slipper assembly of an excavator hydraulic pump, including:

[0006] A plunger, with a cavity inside the plunger, a ball head provided at the end of the plunger, and a central hole passing through the ball head and communicating with the cavity provided at the center of the plunger;

[0007] A slipper, with a spherical connection groove for connecting with the ball head, and an expansion groove provided inside the spherical connection groove at the center of the slipper for storing the oil fluid delivered by the central hole;

[0008] A sealing ring is provided on the friction surface of the slipper to form an internal oil storage groove on the friction surface of the slipper, and an oil outlet hole for communicating the internal oil storage groove and the expansion groove is provided at the center of the slipper;

[0009] Among them, a one-way oil outlet pipe is arranged in the oil outlet hole. The one-way oil outlet pipe is arranged in a circular tubular structure with one end open and one end closed, and the open end of the one-way oil outlet pipe faces the expansion slot. A plurality of oil discharge parts are arranged on the side wall of the slipper near the closed end in a circumferentially uniform arrangement. The one-way oil outlet pipe has an open state and a closed state;

[0010] When the plunger is in the oil pumping state, under the action of pressure, the one-way oil outlet pipe moves towards the friction surface of the slipper. After the oil discharge part moves to the outside of the oil outlet hole, the oil can be input into the internal oil storage tank through the oil discharge part, and the one-way oil outlet pipe is in the open state;

[0011] When the plunger is in the oil suction state, under the action of negative pressure, the one-way oil outlet pipe slides towards one side of the plunger. After the oil discharge part moves to the inside of the oil outlet hole, it is closed, and the one-way oil outlet pipe is in the closed state.

[0012] Preferably, a narrowing part is arranged on the side surface of the one-way oil outlet pipe near the closed end. The oil discharge parts are all arranged at the narrowing part. A channel for the oil to flow is formed between the narrowing part and the inner wall of the oil outlet hole, which can shorten the moving stroke when the state of the one-way oil outlet pipe is switched.

[0013] Preferably, the oil discharge part is composed of a plurality of holes distributed in an array.

[0014] Preferably, a limiting expansion part is arranged at one end of the one-way oil outlet pipe located in the expansion slot. The limiting expansion part is used to limit the moving distance of the one-way oil outlet pipe towards the friction surface of the slipper.

[0015] Preferably, a groove is arranged at one end of the oil outlet hole located on the friction surface of the slipper. When the limiting expansion part is in contact with and limited by the expansion slot, the closed end of the one-way oil outlet pipe is located in the groove.

[0016] Preferably, the groove is arranged in a funnel-shaped structure.

[0017] Preferably, the depth of the groove is 2.0 - 3.0 mm.

[0018] Preferably, an outer support ring is arranged at the outermost edge of the friction surface of the slipper. An outer oil storage tank is formed between the inner oil storage tank and the outer support ring. A plurality of oil inlet ports for the outer oil storage tank to transport oil are arranged on the outer support ring.

[0019] Preferably, the diameter of the inner oil storage tank is 2 / 3 of the diameter of the outermost edge of the friction surface of the slipper.

[0020] Preferably, the depth of the inner oil storage tank and the outer oil storage tank is 1.0 - 2.0 mm.

[0021] Compared with the prior art, the advantages of the present utility model are as follows:

[0022] A one-way oil outlet pipe that functions as a valve is provided in the oil outlet hole for delivering oil fluid to the sliding shoe friction surface. During oil pumping, under the action of pressure, the one-way oil outlet pipe is in an open state, and the oil fluid inside the oil outlet pipe can be input into the internal oil storage tank through the oil discharge part; when the plunger is in the oil suction state, under the action of negative pressure, the one-way oil outlet pipe slides towards one side of the plunger, and the oil discharge part moves to the inside of the oil outlet hole and is sealed, and the one-way oil outlet pipe is in a closed state, and the oil fluid in the internal oil storage tank will not be sucked back into the cylinder block by negative pressure, enabling the internal oil storage tank to maintain sufficient oil fluid for lubrication. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be denoted by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present utility model will be described by way of example and with reference to the drawings, wherein:

[0024] Figure 1 is a schematic structural view of the plunger and sliding shoe assembly of the hydraulic pump of an excavator shown in the present utility model;

[0025] Figure 2 is a cross-sectional view of the sliding shoe in the plunger and sliding shoe assembly of the hydraulic pump of an excavator shown in the present utility model;

[0026] Figure 3 is a schematic view of the installation position of the one-way oil outlet pipe in the plunger and sliding shoe assembly of the hydraulic pump of an excavator shown in the present utility model;

[0027] Figure 4 is a schematic structural view of the sliding shoe friction surface in the plunger and sliding shoe assembly of the hydraulic pump of an excavator shown in the present utility model.

[0028] In the figures, 1, plunger; 11, ball head; 101, cavity; 102, central hole; 2, sliding shoe; 21, sealing ring; 22, internal oil storage tank; 23, outer support ring; 231, oil inlet; 24, outer oil storage tank; 201, spherical connection groove; 202, oil outlet hole; 203, expansion groove; 204, groove; 3, one-way oil outlet pipe; 31, limit expansion part; 32, narrowing part; 301, oil discharge part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] In order to better understand the technical content of the present utility model, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0030] Combined with Figures 1-4 shown, the present utility model provides a plunger and sliding shoe assembly of a hydraulic pump for an excavator, including a plunger 1 and a sliding shoe 2.

[0031] The plunger 1 has a cavity 101 inside, a ball head 11 at the end of the plunger 1, and a ball-shaped connecting groove 201 in which the ball head 11 is connected, so that the plunger 1 and the sliding shoe 2 are movably connected to each other.

[0032] Combination Figure 1 and Figure 4 As shown, a center hole 102 is provided at the center of the plunger 1, which passes through the ball head 11 and is connected to the cavity 101. An expansion groove 203 is provided at the center of the sliding shoe 2, which is located inside the ball-type connecting groove 201. The diameter of the expansion groove 203 is larger than the diameter of the center hole 102, so that when the ball head 11 swings, the end of the center hole 102 is always within the range of the expansion groove 203.

[0033] Furthermore, a closed ring 21 is provided on the friction surface of the slipper 2, so that an inner oil storage tank 22 is formed on the friction surface of the slipper 2. An oil outlet hole 202 is opened at the center of the slipper 2 to connect the inner oil storage tank 22 and the expansion tank 203. When the plunger 1 is in the oil pumping state, the oil in the cavity 101 can be transported to the inside of the inner oil storage tank 22 along the center hole 102, the expansion tank 203 and the oil outlet hole 202 under the action of pressure, so that a layer of oil film is formed between the friction surface of the slipper 2 and the inclined plate, which plays a role in lubrication and reducing wear.

[0034] However, during the process of the plunger sucking oil, the pressure in the oil pipeline decreases, and even negative pressure is generated. The oil in the oil groove on the friction surface of the slipper will be sucked into the cylinder body, resulting in insufficient lubrication of the slipper and the swash plate, which intensifies wear.

[0035] Combination Figure 2 and Figure 4 As shown, a one-way oil outlet pipe 3 is provided in the oil outlet hole 202, and the one-way oil outlet pipe 3 is set as a circular tubular structure with one end open and the other end closed, and the open end of the one-way oil outlet pipe 3 faces the expansion groove 203, and the side wall of the sliding shoe 2 close to the closed end is provided with a plurality of circumferentially evenly arranged oil discharge portions 301;

[0036] It can be understood that the one-way oil outlet pipe 3 in the oil outlet hole 202 can act as a valve. When the oil discharge portion 301 on the one-way oil outlet pipe 3 is located outside the oil outlet hole 202, the one-way oil outlet pipe 3 is connected. When the oil discharge portion 301 on the one-way oil outlet pipe 3 is located inside the oil outlet hole 202, the one-way oil outlet pipe 3 is closed.

[0037] Thus, when the plunger 1 is in the oil pumping state, under the action of pressure, the one-way oil outlet pipe 3 moves toward the friction surface of the sliding shoe 2, and after the oil discharge portion 301 moves to the outside of the oil outlet hole 202, the one-way oil outlet pipe 3 is in the open state, and the oil inside the oil outlet pipe 3 can be input into the internal oil storage tank 22 through the oil discharge portion 301, and an oil film is formed between the friction surface of the sliding shoe 2 and the swash plate;

[0038] When the plunger 1 is in the oil suction state, under the action of negative pressure, the one-way oil outlet pipe 3 slides to one side of the plunger 1, and the oil discharge part 301 is moved into the oil outlet hole 202 and then sealed. The one-way oil outlet pipe 3 is in a closed state, and the oil in the internal oil storage tank 22 will not be sucked back into the cylinder block by negative pressure, so that the internal oil storage tank 22 maintains sufficient oil for lubrication.

[0039] In a preferred embodiment, the oil discharge part 301 is composed of a plurality of holes distributed in an array, making the oil discharge more uniform.

[0040] Combined Figure 3 As shown, a narrowing part 32 is provided on the side of the one-way oil outlet pipe 3 close to the closed end, and the oil discharge parts 301 are all arranged at the narrowing part 32. A channel for the oil to flow is formed between the narrowing part 32 and the inner wall of the oil outlet hole 202. When the one-way oil outlet pipe 3 moves and opens, only one end of the narrowing part 32 needs to move outside the oil outlet hole 202, and the entire section of the oil discharge part 301 can discharge oil, without the need to move the entire oil discharge part 301 outside the oil outlet hole 202, which can shorten the moving stroke when the state of the one-way oil outlet pipe 3 is switched.

[0041] Further, a limiting and expanding part 31 is provided at one end of the one-way oil outlet pipe 3 located in the expansion groove 203. The limiting and expanding part 31 is used to limit the distance that the one-way oil outlet pipe 3 moves towards the friction surface of the slipper 2. A groove 204 is provided at one end of the oil outlet hole 202 located at the friction surface of the slipper 2. When the limiting and expanding part 31 is in contact and limited with the expansion groove 203, the closed end of the one-way oil outlet pipe 3 is located in the groove 204, avoiding the contact and friction between the closed end of the one-way oil outlet pipe 3 and the slipper.

[0042] In an alternative embodiment, the depth of the groove 204 is 2.0 - 3.0 mm, preferably 3.0 mm. The deeper groove 204 enables the one-way oil outlet pipe 3 to extend a longer distance when moving and opening, increasing the area of the oil discharge channel and improving the oil discharge volume.

[0043] In an alternative embodiment, the groove 204 is arranged in a funnel-shaped structure, which can enable the oil to quickly diffuse into the internal oil storage tank 22.

[0044] Combined Figure 4 As shown, an outer support ring 23 is provided at the outermost edge of the friction surface of the slipper 2. An outer oil storage tank 24 is formed between the internal oil storage tank 22 and the outer support ring 23. A plurality of oil inlet ports 231 for supplying oil to the outer oil storage tank 24 are provided on the outer support ring 23, enabling the oil in the pump housing to enter the outer oil storage tank 24 through the oil inlet ports 231.

[0045] When the plunger pump is initially started, the pressure is small and the oil in the internal oil storage tank 22 is insufficient. At this time, the oil in the outer oil storage tank 24 can form an oil film between the friction surface of the slipper 2 and the swash plate, playing a lubricating role and avoiding wear caused by insufficient lubrication when the plunger pump starts.

[0046] Further, the diameter of the internal oil storage groove 22 is 2 / 3 of the diameter of the outermost edge of the friction surface of the slipper 2, so that the oil film formed by the internal oil storage groove 22 can cover the friction surface of the slipper 2 to the greatest extent and reduce wear.

[0047] In an alternative embodiment, the depths of the internal oil storage groove 22 and the external oil storage groove 24 are 1.0 - 2.0 mm, preferably 2.0 mm, so that they can store a sufficient amount of oil inside and form an oil film between the friction surface of the slipper 2 and the swash plate.

[0048] Combined with the above embodiments, a one-way oil outlet pipe 3 acting as a valve is arranged in the oil outlet hole 202 for delivering oil to the friction surface of the slipper 2. During oil pumping, under the action of pressure, the one-way oil outlet pipe 3 is in an open state, and the oil inside the oil outlet pipe 3 can be input into the internal oil storage groove 22 through the oil discharging part 301; when the plunger 1 is in the oil suction state, under the action of negative pressure, the one-way oil outlet pipe 3 slides towards one side of the plunger 1, and after the oil discharging part 301 moves into the oil outlet hole 202 and is closed, the one-way oil outlet pipe 3 is in a closed state, and the oil in the internal oil storage groove 22 will not be sucked back into the cylinder block by negative pressure, so that a sufficient amount of oil can be maintained inside the internal oil storage groove 22 for lubrication.

[0049] Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Those with ordinary knowledge in the technical field to which the present utility model pertains can make various changes and modifications without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to that defined by the claims.

Claims

1. Excavator hydraulic pump plunger shoe assembly, characterized in that: include: A plunger (1), wherein a cavity (101) is provided inside the plunger (1), a ball head (11) is provided at the end of the plunger (1), and a center hole (102) is provided at the center of the plunger (1) and passes through the ball head (11) and is connected to the cavity (101); A sliding shoe (2), wherein the sliding shoe (2) is provided with a ball-shaped connecting groove (201) for connecting with the ball head (11), and an expansion groove (203) is provided at the center of the sliding shoe (2) and located inside the ball-shaped connecting groove (201) for storing oil delivered by the center hole (102); The friction surface of the sliding shoe (2) is provided with a closed ring (21), so that the friction surface of the sliding shoe (2) forms an inner oil storage groove (22), and the center of the sliding shoe (2) is provided with an oil outlet hole (202) that connects the inner oil storage groove (22) and the expansion groove (203); A one-way oil outlet pipe (3) is provided in the oil outlet hole (202), and the one-way oil outlet pipe (3) is a circular tubular structure with one end open and the other end closed, and the open end of the one-way oil outlet pipe (3) faces the expansion groove (203), and a plurality of circumferentially evenly arranged oil discharge portions (301) are provided on the side wall of the sliding shoe (2) near the closed end, and the one-way oil outlet pipe (3) has an open state and a closed state; When the plunger (1) is in an oil pumping state, under the action of pressure, the one-way oil outlet pipe (3) moves toward the friction surface of the sliding shoe (2), and after the oil discharge portion (301) moves to the outside of the oil outlet hole (202), the oil can be input into the internal oil storage tank (22) through the oil discharge portion (301), and the one-way oil outlet pipe (3) is in an open state; When the plunger (1) is in the oil suction state, under the action of negative pressure, the one-way oil outlet pipe (3) slides toward one side of the plunger (1), and the oil discharge portion (301) moves to the inside of the oil outlet hole (202) and is then closed, and the one-way oil outlet pipe (3) is in a closed state.

2. The excavator hydraulic pump plunger shoe assembly according to claim 1, characterized in that: The side surface of the one-way oil outlet pipe (3) close to the closed end is provided with a narrowing portion (32), and the oil discharge portion (301) is arranged at the narrowing portion (32). A channel for the flow of oil is formed between the narrowing portion (32) and the inner wall of the oil outlet hole (202), which can shorten the movement stroke of the one-way oil outlet pipe (3) when switching states.

3. The excavator hydraulic pump plunger shoe assembly according to claim 1, characterized in that: The oil discharge portion (301) is composed of a plurality of holes distributed in an array.

4. The excavator hydraulic pump plunger shoe assembly according to claim 3, characterized in that: The one-way oil outlet pipe (3) is provided with a limit expansion portion (31) at one end of the expansion groove (203), and the limit expansion portion (31) is used to limit the distance that the one-way oil outlet pipe (3) moves toward the friction surface of the sliding shoe (2).

5. The excavator hydraulic pump plunger shoe assembly according to claim 4, characterized in that: The oil outlet hole (202) is located at one end of the friction surface of the sliding shoe (2) and is provided with a groove (204). When the limiting expansion portion (31) and the expansion groove (203) are in contact with each other for limiting, the closed end of the one-way oil outlet pipe (3) is located in the groove (204).

6. The excavator hydraulic pump plunger shoe assembly according to claim 5, characterized in that: The groove (204) is configured as a funnel-shaped structure.

7. The excavator hydraulic pump plunger shoe assembly according to claim 5, characterized in that: The depth of the groove (204) is 2.0-3.0 mm.

8. The excavator hydraulic pump plunger shoe assembly according to claim 1, characterized in that: An outer support ring (23) is provided at the outermost edge of the friction surface of the sliding shoe (2), an outer oil storage groove (24) is formed between the inner oil storage groove (22) and the outer support ring (23), and a plurality of oil inlets (231) for supplying oil to the outer oil storage groove (24) are provided on the outer support ring (23).

9. The excavator hydraulic pump plunger shoe assembly according to claim 1, characterized in that: The diameter of the inner oil storage tank (22) is 2 / 3 of the diameter of the outermost edge of the friction surface of the sliding shoe (2).

10. The excavator hydraulic pump plunger shoe assembly according to claim 8, characterized in that: The depths of the inner oil storage groove (22) and the outer oil storage groove (24) are 1.0-2.0 mm.

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