Self-lubricating mechanism of two-dimensional piston pump space cam and lubricating method thereof

Abstract

This invention discloses a self-lubricating mechanism for a two-dimensional piston pump spatial cam, comprising a pump body and a cam assembly. The pump body includes a piston shaft and a pump housing, with an end cap containing an oil chamber at one end of the pump housing. The piston shaft has a first flow channel communicating with the oil chamber of the end cap. The cam assembly includes a sleeve and a cam and a roller shaft disposed within the sleeve. The roller shaft has a second flow channel communicating with the first flow channel and a third flow channel communicating with the second flow channel. The third flow channel radially penetrates the annular end face of the roller shaft. The pump housing also has a fourth flow channel communicating with the inner cavity of the sleeve, and the other end of the fourth flow channel is connected to an outlet pipe connected to the end cap. Oil is input through the inlet pipe of the end cap, flows through the first, second, and third flow channels, and then enters the friction pair between the bearing and the cam for lubrication. The lubricated oil is discharged from the outlet pipe through the fourth flow channel, forming a complete self-lubricating mechanism. The self-lubricating process of this application does not require additional oil supply power to achieve the self-lubricating effect of the spatial cam.

Description

Technical Field

[0001] This invention belongs to the field of piston pump technology, specifically relating to a self-lubricating mechanism and lubrication method for a two-dimensional piston pump spatial cam. Background Technology

[0002] Compared to traditional piston pumps, the piston shaft of a two-dimensional piston hydraulic pump rotates and moves linearly under the action of a spatial cam, thus achieving the switching between suction and discharge of fluid in the working chamber. Two-dimensional piston hydraulic pumps have advantages such as simple structure, small size, and light weight.

[0003] A two-dimensional piston pump converts the circumferential rotation of the piston shaft driven by the motor into the axial reciprocating motion of the piston shaft through a spatial cam. Rollers and roller shafts are mounted on the piston shaft, with rolling bearings between the rollers and roller shafts to reduce friction. However, because the cam surface is a curved surface with a certain height difference, wear is still significant under the high speed of the motor and the hydraulic pressure generated by the pump body, necessitating lubrication of the spatial cam to further reduce friction. Existing lubrication methods (such as oil immersion lubrication) also generate significant oil churning losses during lubrication; therefore, targeted lubrication of the cam surface is more suitable. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a self-lubricating mechanism for a two-dimensional piston pump spatial cam, which satisfies the lubrication of the spatial cam during the high-speed operation of the piston pump, thereby solving the lubrication loss problem of the existing spatial cam mechanism.

[0005] A self-lubricating mechanism for a two-dimensional piston pump spatial cam includes a pump body and a cam assembly connected in a mating manner. The pump body includes a piston shaft and a pump housing sleeved outside the piston shaft. An end cap is provided at the end of the pump housing away from the cam assembly. The end cap has an oil chamber, with an outlet at its top communicating with the oil chamber and an inlet at its bottom communicating with the oil chamber. The piston shaft has a first flow channel along its length communicating with the oil chamber of the end cap. The cam assembly includes a sleeve and a cam and a roller shaft disposed within the sleeve. Bearings are provided at both ends of the roller shaft to roll in engagement with the cam. The roller shaft is inserted into the piston shaft, and... The roller shaft has a second flow channel communicating with the first flow channel, and the second flow channel axially passes through both ends of the roller shaft; the roller shaft has a third flow channel communicating with the second flow channel near the bearing, and the third flow channel radially passes through the annular end face of the roller shaft; in addition, the pump housing also has a fourth flow channel communicating with the inner cavity of the sleeve, and the other end of the fourth flow channel is connected to the liquid outlet pipe connected to the end cover; the oil is input through the liquid inlet pipe of the end cover, flows through the first flow channel, the second flow channel and the third flow channel and enters the friction pair between the bearing and the cam for lubrication, and the lubricated oil is discharged from the liquid outlet pipe through the fourth flow channel, forming a complete spatial cam self-lubricating mechanism.

[0006] Furthermore, the end cap is a cup-shaped cap with an oil chamber inside. Its annular wall has an outlet on the top wall and an inlet on the bottom wall. The inlet is connected to an inlet pipe, and the outlet is connected to an outlet pipe. A sealing ring groove is provided at the connection position between the end cap and the pump housing to accommodate a sealing ring and prevent oil leakage.

[0007] Furthermore, the cam includes a first cam and a second cam that are sleeved on opposite sides of the piston shaft. A base is provided on the opposite side of the first cam and the second cam. The outer diameter of the base is larger than the outer diameter of the first cam and the second cam. The two bases are connected by a sleeve. The sleeve contains the movable cavity between the cam and the roller shaft.

[0008] Furthermore, a first roller shaft that rolls with the first cam and a second roller shaft that rolls with the second cam are provided between the first cam and the second cam. Both the first roller shaft and the second roller shaft are inserted on the piston shaft and are perpendicular to each other. Both the first roller shaft and the second roller shaft are provided with a second flow channel that communicates with the first flow channel of the piston shaft. The second flow channel extends axially through both ends of the first roller shaft and the second roller shaft. Shafts are provided at both ends of the first roller shaft to roll against the first cam. Bearings are provided at both ends of the second roller shaft to roll against the second cam. A third flow channel is provided at both ends of the first roller shaft and the second roller shaft, which is perpendicular to and communicates with the second flow channel.

[0009] Furthermore, the roller shaft has an annular groove in the middle of its annular end face, and the connection between the second flow channel and the first flow channel is located in the annular groove. Oil can flow from the first flow channel of the piston shaft into the annular groove and then from the annular groove into the second flow channel. The third flow channel is located on the roller shaft between the piston shaft and the bearing and close to the bearing side. Oil flows through the third flow channel to the friction pair between the bearing and the cam to provide frictional lubrication for the bearing and the cam.

[0010] Furthermore, the base near the pump housing is connected to the pump housing, and the base is provided with two through holes, which are located relatively far from the piston shaft. The inner cavity of the sleeve is connected to the fourth flow channel through the two through holes.

[0011] Furthermore, the fourth flow channel includes a first pipe disposed in the inner cavity of the pump housing perpendicular to the piston shaft and a second pipe disposed on the inner wall of the pump housing parallel to the piston shaft. One end of the first pipe is connected to one of the through holes, and the other end is connected to the second pipe. One end of the second pipe is connected to another through hole, and the other end extends out of the pump housing and is connected to the liquid outlet pipe on the end cover. The first pipe and the second pipe are connected perpendicularly.

[0012] Another objective of this invention is to provide a lubrication method for a self-lubricating mechanism of a two-dimensional piston pump spatial cam, the specific steps of which include:

[0013] S1. Lubricating oil enters the end cap through an oil pipe connected to the inlet at the lower end of the end cap;

[0014] S2. The oil in the end cover enters the annular groove of the roller shaft through the first flow channel in the piston shaft, and the excess oil is discharged through the outlet on the end cover.

[0015] S3. The oil in the annular groove enters the second flow channel;

[0016] S4. The oil in the second flow channel enters the third flow channel through its connection with the third flow channel;

[0017] S5. The pressure difference generated by the piston pump during the operation of the oil in the third flow channel affects the flow to the friction pair between the bearing and the cam;

[0018] S6. After passing through the friction pair between the bearing and the cam, the oil enters the fourth flow channel through the through hole of the base and is discharged to the outlet pipe, completing the oil lubrication cycle.

[0019] Compared with the prior art, the present invention has the following advantages: The piston shaft is connected to the motor through a coupling. The motor drives the piston shaft to rotate, and the roller shaft rotates accordingly. When running at high speed, the third flow channel in the roller shaft forms a low-pressure zone, while the second flow channel in the roller shaft is connected to the first flow channel in the piston shaft. The oil in the low-pressure zone and the oil near the end cap of the piston shaft form a pressure difference. Under the action of suction, the oil entering from the lower port of the end cap flows through the first flow channel and the second flow channel in sequence and then flows through the radial third flow channel on the roller shaft to the contact point between the bearing and the cam to provide frictional lubrication for the bearing and the cam. After passing through the contact point between the bearing and the cam, the oil flows through pipe one and pipe two to the outlet, completing the lubrication cycle of the oil. This process can achieve the self-lubricating effect of the cam space without the need for additional oil supply power. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 For the present invention Figure 1 Sectional view at point AA;

[0022] Figure 3 This is a schematic diagram of the internal structure of the present invention after removing the sleeve, cylinder body and pump housing;

[0023] Figure 4 This is a connection structure diagram of the piston shaft and roller shaft of the present invention;

[0024] Figure 5 This is a schematic diagram of the piston shaft structure of the present invention;

[0025] Figure 6 This is a schematic diagram of the structure of the roller shaft of the present invention.

[0026] In the diagram: 1-Pump body, 11-Piston shaft, 12-Cylinder body, 13-Pump housing, 2-Cam assembly, 21-Cam, 211-First cam, 212-Second cam, 213-Base, 22-Roller shaft, 221-First roller shaft, 222-Second roller shaft, 23-Bearing 2, 24-Sleeve, 25-Annular groove, 3-End cap, 31-Inlet, 32-Outlet, 33-Inlet pipe, 34-Outlet pipe, 35-Sealing ring groove, 4-Coupling, 10-First flow channel, 20-Second flow channel, 30-Third flow channel, 40-Fourth flow channel, 41-Pipe 1, 42-Pipe 2. Detailed Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] like Figures 1-6 As shown, a self-lubricating mechanism for a two-dimensional piston pump spatial cam includes a pump body 1 and a cam assembly 2 connected in a mating manner. The pump body 1 includes a piston shaft 11 and a cylinder 12 sleeved on the piston shaft 11. A pump housing 13 is sleeved on the cylinder 12. An end cap 3 is provided at the end of the pump housing 13 away from the cam assembly 2. The end cap 3 has an oil chamber inside, with an inlet 31 at its bottom communicating with the oil chamber and an outlet 32 ​​at its top communicating with the oil chamber. The inlet 31 is connected to an inlet pipe 33, and the outlet 32 ​​is connected to an outlet pipe 34. The piston shaft 11 has a first flow channel 10 along its length that communicates with the oil chamber of the end cap 3. The other end of the piston shaft 11, which extends out of the pump housing 13, is connected in a mating manner to a coupling 4. A cam assembly 2 is provided at the end of the piston shaft 11 near the coupling 4. The cam assembly 2 includes a sleeve 24 and a cam 21 and a roller shaft 22 disposed within the sleeve 24. Bearings 23 are provided at both ends of the roller shaft 22 and the cam 21. In a rolling fit, cam 21 is sleeved on piston shaft 11, and piston shaft 11 passes through the central hole of cam 21 and can rotate along the central hole; roller shaft 22 is inserted on piston shaft 11 and rotates with piston shaft 11, and roller shaft 22 has a second flow channel 20 communicating with the first flow channel 10, and the second flow channel 20 axially passes through roller shaft 22; near bearing 23 on roller shaft 22, there is a third flow channel 30 perpendicular to the second flow channel 20, and the third flow channel 30 radially passes through roller shaft 22; and pump housing 13 has a fourth flow channel 40 communicating with the inner cavity of sleeve 24, and the other end of the fourth flow channel 40 passes through pump housing 13 and communicates with the liquid outlet pipe connected to end cover 3; oil is input through the liquid inlet pipe of end cover 3, flows through the first flow channel 10, the second flow channel 20 and the third flow channel 30 to lubricate the friction pair between bearing 23 and cam 21, and then is discharged through the fourth flow channel 40 and the liquid outlet pipe, forming a complete cam lubrication mechanism.

[0029] Specifically, the cam 21 includes a first cam 211 and a second cam 212 that are sleeved on the piston shaft 11. A base 213 is provided on the opposite side of the first cam 211 and the second cam 212. The outer diameter of the base 212 is larger than the outer diameter of the first cam 211 and the second cam 212. The two bases 213 are connected by a sleeve 24. The sleeve 24 provides a movable cavity for the cam 21 and the roller shaft 22. A first roller shaft 221 that rolls with the first cam 211 and a second roller shaft 222 that rolls with the second cam 212 are provided between the first cam 211 and the second cam 212. Both the first roller shaft 221 and the second roller shaft 222 are inserted on the piston shaft 11 and are perpendicular to each other. Both the first roller shaft 221 and the second roller shaft 222 are provided with a second flow channel 20 that communicates with the first flow channel 10 of the piston shaft 11. The second flow channel 20 passes through both ends of the first roller shaft 221 and the second roller shaft 222. Bearings 23 are provided at both ends of the first roller shaft 221 to roll against the first cam 211, and bearings 23 are provided at both ends of the second roller shaft 222 to roll against the second cam 212. Both ends of the first roller shaft 221 and the second roller shaft 222 are provided with a third flow channel 30 that is perpendicular to and communicates with the second flow channel. In order to ensure the discharge pressure of the oil in the third flow channel 30, the third flow channel 30 is preferably set on the roller shaft 22 between the piston shaft 11 and the bearing 23 and close to the bearing 23. The oil flows through the third flow channel 30 to the contact point between the bearing 23 and the cam 21 to provide frictional lubrication for the bearing 23 and the cam 21.

[0030] The end cap 3 is a cup-shaped cap with an oil chamber inside. The top wall of the annular wall is provided with an outlet 32 ​​and the bottom wall is provided with an inlet 31. The outlet 32 ​​is used to connect to the outlet pipe 34 and the inlet is used to connect to the inlet pipe 33. Both the outlet pipe 33 and the inlet pipe 34 are 5mm oil pipes, and both the outlet 32 ​​and the inlet 31 are 5mm diameter oil pipe openings. A sealing ring groove 35 is opened at the connection position between the end cap 3 and the pump housing 13 to place a sealing ring to prevent oil leakage.

[0031] A base 213, located near the pump housing 13, is connected to the pump housing 13. This base 212 has two through holes positioned relatively away from the piston shaft 11. The inner cavity of the sleeve 23 communicates with the fourth flow channel 40 through these two through holes. The fourth flow channel 40 includes a first pipe 41 located inside the pump housing 13 perpendicular to the piston shaft 11 and a second pipe 42 located on the inner wall of the pump housing 13 parallel to the piston shaft 11. One end of the first pipe 41 communicates with one of the through holes, and the other end communicates with the second pipe 42. One end of the second pipe 42 communicates with the other through hole, and the other end extends out of the pump housing 13 and communicates with the liquid outlet pipe of the end cap 3. The first pipe 41 and the second pipe 42 are vertically connected. In this application, the flow channel diameter of the first pipe 41 is 1 mm, and the diameter of the through hole is 2 mm. The first pipe 41 communicates with the inner cavity of the sleeve 23 through the 2 mm through hole. The diameter of pipe 2 42 is 2mm-3mm. A 5mm oil pipe port is provided at the connection between pipe 2 42 and pump casing 13 to connect oil pipe 33.

[0032] To ensure the flow between the first flow channel 10 and the second flow channel 20, an annular groove 25 with a depth of 0.5mm-1mm is cut into the middle section of the roller shaft 22. The connection between the second flow channel 20 and the first flow channel is located within the section of the annular groove 25. Oil can flow from the first flow channel 10 of the piston shaft 11 through the annular groove 25 into the second flow channel 20. A radially flowing third flow channel 30 is provided on the shaft section near the bearing 23 on the roller shaft 22. The diameter of the third flow channel 30 is 1mm. To allow oil to flow into the contact surface between the cam 21 and the bearing 23, both ends of the roller shaft 22 can be sealed. The diameter of the first flow channel 10 is 1mm.

[0033] It is understood that the piston shaft 11 is connected to the motor via coupling 4. The motor drives the piston shaft 11 to rotate, and the roller shaft 22 rotates accordingly. During high-speed operation, a low-pressure zone is formed in the third flow channel 30 port inside the roller shaft 22. The second flow channel 20 inside the roller shaft 22 is connected to the first flow channel 10 inside the piston shaft 11. A pressure difference is formed between the oil in the low-pressure zone and the oil near the end cap 3 of the piston shaft 11. Under the action of suction, the oil entering from the lower port of the end cap 3 flows through the first flow channel 10 and the second flow channel 20 in sequence, and then flows through the radial third flow channel 30 on the roller shaft 22 to the contact point between the bearing 23 and the cam, so as to provide frictional lubrication for the bearing 23 and the cam 22. After passing through the contact point between the bearing 23 and the cam, the oil flows through pipe 1 41 and pipe 2 42 to the outlet, completing the oil lubrication cycle. No additional oil supply is required, and a self-lubricating effect can be achieved.

[0034] In addition, the outlet pipe 34 connected to the end cover 3 can discharge excess oil entering the inlet pipe 33 without affecting the operation of the pump; and the leaked oil in the sleeve 23 can also be discharged through the through hole on the base 213 to pipe 41 and pipe 42, thus avoiding the accumulation of oil in the operating space of the cam 21.

[0035] The specific steps of the self-lubricating method for the two-dimensional piston pump of the present invention include:

[0036] Lubricating oil enters end cap 3 through oil pipe 33 connected to inlet 31 at the lower end of end cap 3;

[0037] The oil inside the end cover 3 enters the annular groove 25 of the roller shaft 22 through the first flow channel 10 inside the piston shaft 11, and the excess is discharged through the outlet 32 ​​on the end cover 3.

[0038] The oil in the annular groove 25 enters the second flow channel 20;

[0039] The oil in the second flow channel 20 enters the third flow channel 30 through its connection with the third flow channel 30;

[0040] The oil passage of the third flow channel 30 is discharged by the pressure difference generated when the piston pump is running, and flows to the friction pair between the bearing 23 and the cam 21.

[0041] The lubricating oil passing through the friction pair between bearing 23 and cam 21 enters the fourth flow channel 40 through the through hole of base 213 and is then discharged to outlet pipe 34, completing the lubrication cycle of the oil.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-lubricating mechanism for a two-dimensional piston pump spatial cam, comprising a pump body (1) and a cam assembly (2) connected in a mating manner, wherein the pump body (1) includes a piston shaft (11) and a pump housing (13) sleeved outside the piston shaft (11), and an end cap (3) is provided at the end of the pump housing (13) away from the cam assembly (2), characterized in that, The end cap (3) has an oil chamber inside, with an outlet (32) communicating with the oil chamber at the top and an inlet (31) communicating with the oil chamber at the bottom; the piston shaft (11) has a first flow channel (10) communicating with the oil chamber of the end cap (3) along its length; the cam assembly (2) includes a sleeve (24) and a cam (21) and a roller shaft (22) disposed in the sleeve (24), bearings (23) are provided at both ends of the roller shaft (22) to roll with the cam (21), the roller shaft (22) is inserted on the piston shaft (11), and a second flow channel (20) communicating with the first flow channel (10) is provided inside the roller shaft (22), the second flow channel (20) axially penetrating both ends of the roller shaft (22). The roller shaft (22) is provided with a third flow channel (30) connected to the second flow channel (20) near the bearing (23). The third flow channel (30) radially penetrates the annular end face of the roller shaft (22). In addition, the pump housing (13) is also provided with a fourth flow channel (40) connected to the inner cavity of the sleeve (24). The other end of the fourth flow channel (40) is connected to the outlet pipe (34) connected to the end cover (3). The oil is input through the inlet pipe (33) of the end cover (3), flows through the first flow channel (10), the second flow channel (20) and the third flow channel (30) and enters the friction pair between the bearing (23) and the cam (21) for lubrication. The lubricated oil is discharged from the outlet pipe through the fourth flow channel (40), forming a complete spatial cam self-lubricating mechanism. The roller shaft (22) has an annular groove (25) in the middle of its annular end face. The connection between the second flow channel (20) and the first flow channel (10) is located in the annular groove (25). Oil can flow into the annular groove (25) from the first flow channel (10) of the piston shaft (11) and then flow into the second flow channel (20) from the annular groove (25). The third flow channel (30) is located on the roller shaft (22) between the piston shaft (11) and the bearing (23) and close to the bearing (23). Oil flows through the third flow channel (30) to the friction pair between the bearing (23) and the cam (21) for frictional lubrication of the bearing (23) and the cam (21).

2. The self-lubricating mechanism of a two-dimensional piston pump spatial cam according to claim 1, characterized in that, The end cap (3) is a cup-shaped cap with an oil chamber inside. The top wall of its annular wall is provided with an outlet (32) and the bottom wall is provided with an inlet (31). The inlet (31) is connected to the inlet pipe (33) and the outlet (32) is connected to the outlet pipe (34). A sealing ring groove (35) is opened at the connection position between the end cap (3) and the pump housing (13) to place the sealing ring to prevent oil leakage.

3. The self-lubricating mechanism of a two-dimensional piston pump spatial cam according to claim 1, characterized in that, The cam (21) includes a first cam (211) and a second cam (212) that are sleeved on the piston shaft (11) facing each other. The first cam (211) and the second cam (212) are each provided with a base (213) on the opposite side. The outer diameter of the base (213) is larger than the outer diameter of the first cam (211) and the second cam (212). The two bases (213) are connected by a sleeve (24). The sleeve (24) contains the movable cavity of the cam (21) and the roller shaft (22).

4. The self-lubricating mechanism of a two-dimensional piston pump spatial cam according to claim 3, characterized in that, A first roller shaft (221) that rolls with the first cam (211) and a second roller shaft (222) that rolls with the second cam (212) are provided between the first cam (211) and the second cam (212). Both the first roller shaft (221) and the second roller shaft (222) are inserted on the piston shaft (11) and are perpendicular to each other. Both the first roller shaft (221) and the second roller shaft (222) are provided with a first flow channel (10) that passes through the piston shaft (11). The second flow channel (20) is axially connected to both ends of the first roller shaft (221) and the second roller shaft (222). The first roller shaft (221) is provided with bearings (23) at both ends to roll against the first cam (211); the second roller shaft (222) is provided with bearings (23) at both ends to roll against the second cam (212); and both ends of the first roller shaft (221) and the second roller shaft (222) are provided with a third flow channel (30) that is perpendicular to and connected to the second flow channel (20).

5. The self-lubricating mechanism of a two-dimensional piston pump spatial cam according to claim 3, characterized in that, The base (213) on the side near the pump housing (13) is connected to the pump housing (13), and the base (213) is provided with two through holes. The two through holes are located relatively away from the piston shaft (11). The inner cavity of the sleeve (24) is connected to the fourth flow channel (40) through the two through holes.

6. The self-lubricating mechanism of a two-dimensional piston pump spatial cam according to claim 5, characterized in that, The fourth flow channel (40) includes a first pipe (41) disposed in the inner cavity of the pump housing (13) perpendicular to the piston shaft (11) and a second pipe (42) disposed on the inner wall of the pump housing (13) parallel to the piston shaft (11). One end of the first pipe (41) is connected to one of the through holes, and the other end is connected to the second pipe (42). One end of the second pipe (42) is connected to another through hole, and the other end passes through the pump housing (13) and is connected to the liquid outlet pipe on the end cap (3). The first pipe (41) and the second pipe (42) are connected perpendicularly.

7. The lubrication method for the self-lubricating mechanism of a two-dimensional piston pump spatial cam as described in claim 6, characterized in that, The specific steps include: S1. Lubricating oil enters the end cap (3) through the oil pipe connected to the inlet (31) at the lower end of the end cap (3). S2. The oil in the end cap (3) enters the annular groove (25) of the roller shaft (22) through the first flow channel (10) in the piston shaft (11), and the excess oil is discharged through the outlet (32) on the end cap (3); S3. The oil in the annular groove (25) enters the second flow channel (20); S4. The oil in the second flow channel (20) enters the third flow channel (30) through its connection with the third flow channel (30). S5. The pressure difference generated by the piston pump when the oil in the third flow channel (30) is running affects the flow to the friction pair between the bearing (23) and the cam (21); S6. After passing through the friction pair of the bearing (23) and the cam (21), the oil enters the fourth flow channel (40) through the through hole of the base (213) and is discharged to the outlet pipe (34) to complete the lubrication cycle of the oil.

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