Axial piston pump one-way control valve and control method

Abstract

The present invention discloses a one-way control valve and a control method for an axial piston pump. The one-way control valve includes a valve sleeve (1), a spool (3) is slidably connected inside the valve sleeve (1), a spring (2) connected to the valve sleeve (1) is provided on one side of the spool (3), a plug (5) is provided on the other side of the spool (3), a guide hole (50) is axially provided in the plug (5), and a push rod (4) is provided in the guide hole (50); a liquid discharge hole passage (10) and a liquid replenishing hole passage (11) are provided on the side wall of the valve sleeve (1); a first oil passage (30) and a second oil passage (31) are provided on the spool (3), one end of the first oil passage (30) and one end of the second oil passage (31) are both communicated with the inner cavity of the valve sleeve (1), the other end of the first oil passage (30) is located between the liquid discharge hole passage (10) and the liquid replenishing hole passage (11), and the other end of the second oil passage (31) is communicated with the liquid replenishing hole passage (11). The present invention has the advantages of fast response speed and low failure rate.

Description

Technical Field

[0001] The present invention belongs to the field of axial piston pumps, and particularly relates to a one-way control valve and a control method for an axial piston pump. Background Art

[0002] The axial piston pump is a type of positive displacement hydraulic pump. Due to its compact structure, small radial dimension, and small moment of inertia, it has been widely used in agricultural machinery, construction machinery, metallurgy, aviation and other fields.

[0003] The axial piston pump generally has a high-pressure overflow one-way valve. The structure of the existing high-pressure overflow one-way valve is as Figure 3 shown. Its function is to limit the peak operating pressure of the piston pump and form a one-way valve with other parts to realize the oil filling of the low-pressure cavity of the piston pump. The existing high-pressure overflow one-way valve is a split structure, composed of a high-pressure overflow valve and a one-way valve. Among them, the high-pressure overflow valve is used as the valve core of the one-way valve. After being assembled with other parts of the one-way valve, the high-pressure overflow one-way valve is formed. When controlling the on-off of the oil filling of the axial piston pump, the high-pressure overflow valve, as the valve core of the one-way valve, needs to slide repeatedly in the orifice of the one-way valve. The high-pressure overflow one-way valve with the above structure is equipped with the LHPV-37-L-01C type axial piston pump.

[0004] However, as Figure 4 shown, due to the intersection of multiple oil channels on the wall of the orifice of the one-way valve, the high-pressure overflow valve is prone to sliding jamming due to the damage of the orifice wall, resulting in the inability to control the on-off of the oil filling circuit in time and a slow response speed. In addition, since the traditional high-pressure overflow valve controls the on-off of the overflow orifice by repeatedly compressing the spring with a pull rod, the pull rod has a problem of fatigue fracture and a high failure rate.

[0005] Therefore, the existing high-pressure overflow one-way valve has the defects of slow response speed and high failure rate. Summary of the Invention

[0006] The purpose of the present invention is to provide a one-way control valve and a control method for an axial piston pump. The present invention has the advantages of fast response speed and low failure rate.

[0007] The technical solution of the present invention: The one-way control valve for an axial piston pump includes a valve sleeve. A valve core is slidably connected inside the valve sleeve. A spring connected to the valve sleeve is provided on one side of the valve core. A plug is provided on the other side of the valve core. A guide hole is axially provided on the plug, and a push rod is provided inside the guide hole;

[0008] A liquid discharge hole and a liquid filling hole are provided on the side wall of the valve sleeve;

[0009] The valve core is provided with a first oil passage and a second oil passage. One end of the first oil passage and one end of the second oil passage are both communicated with the inner cavity of the valve sleeve. The other end of the first oil passage is located on the side wall of the valve core and between the liquid discharge hole passage and the liquid replenishment hole passage. The other end of the second oil passage is located on the side wall of the valve core and is communicated with the liquid replenishment hole passage.

[0010] In the axial piston pump one-way control valve described above, the guide hole includes a middle hole slidably connected to the ejector rod. A bottom hole is provided at one end of the middle hole close to the valve core, and a top hole is provided at one end of the middle hole far from the valve core. The diameters of the top hole, the middle hole, and the bottom hole increase in sequence.

[0011] In the axial piston pump one-way control valve described above, a balance hole is provided on the end face of the valve core close to the ejector rod. One end of the balance hole is communicated with the bottom hole, and the other end of the balance hole is communicated with the second oil passage.

[0012] In the axial piston pump one-way control valve described above, one end of the valve sleeve contracts inward to form a stepped surface. One end of the spring is elastically connected to the valve core, and the other end of the spring is elastically connected to the stepped surface.

[0013] In the axial piston pump one-way control valve described above, a blind hole into which the spring is inserted is provided at one end of the valve core; the first oil passage includes a first annular groove on the outer peripheral surface of the valve core, and a first through hole is provided on the bottom surface of the first annular groove. The first through hole is communicated with the blind hole; the second oil passage includes a second annular groove on the outer peripheral surface of the valve core, and a second through hole is provided on the bottom surface of the second annular groove. The second through hole is communicated with the bottom surface of the blind hole.

[0014] In the control method of the axial piston pump one-way control valve described above, by presetting the spring stiffness, the required overflow pressure of the one-way control valve is achieved.

[0015] Compared with the prior art, through structural optimization, the present invention uses the movement of the valve core in the valve sleeve to change the oil flow trajectory. It not only has the function of a one-way valve but also has the function of a high-pressure overflow valve. The structure is simpler, consisting of only five parts. The inner hole of the valve sleeve is regular, without intersecting oil passages, making the valve core move smoothly and the response speed fast. The improved valve core is a single part, replacing the existing high-pressure overflow valve. It has high structural strength, is not prone to fatigue fracture, and the failure rate is significantly reduced. Therefore, the present invention has the advantages of fast response speed and low failure rate. Brief Description of the Drawings

[0016] Figure 1 is the front view of the present invention.

[0017] Figure 2 is the structural schematic diagram of the valve core.

[0018] Figure 3 is the structural schematic diagram of the existing high-pressure overflow valve.

[0019] Figure 4 It is a schematic structural diagram of the passage of the existing one-way valve.

[0020] The reference signs in the accompanying drawings are: 1-valve sleeve, 2-spring, 3-valve core, 4-ejector rod, 5-plug, 10-drainage passage, 11-supplementary liquid passage, 12-step surface, 30-first oil passage, 31-second oil passage, 32-balancing hole, 33-blind hole, 34-first annular groove, 35-first through hole, 36-second annular groove, 37-second through hole, 50-guiding hole, 51-middle hole, 52-bottom hole, 53-top hole. Detailed implementation manners

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but it shall not be used as a basis for limiting the present invention.

[0022] Embodiment. An axial piston pump one-way control valve, as Figure 1 shown, includes a valve sleeve 1. A valve core 3 connected in a sliding manner is arranged inside the valve sleeve 1. A spring 2 connected to the valve sleeve 1 is arranged on one side of the valve core 3. A plug 5 connected by a thread is arranged on the other side of the valve core 3. A guiding hole 50 is axially arranged in the plug 5, and an ejector rod 4 is arranged in the guiding hole 50;

[0023] A drainage passage 10 and a supplementary liquid passage 11 are arranged on the side wall of the valve sleeve 1;

[0024] A first oil passage 30 and a second oil passage 31 are arranged on the valve core 3. One end of the first oil passage 30 and one end of the second oil passage 31 are both communicated with the inner cavity of the valve sleeve 1. The other end of the first oil passage 30 is located on the side wall of the valve core 3 and is between the drainage passage 10 and the supplementary liquid passage 11. The other end of the second oil passage 31 is located on the side wall of the valve core 3 and is communicated with the supplementary liquid passage 11.

[0025] The guiding hole 50 includes a middle hole 51 slidably connected with the ejector rod 4. A bottom hole 52 is arranged at one end of the middle hole 51 close to the valve core 3. A top hole 53 is arranged at one end of the middle hole 51 far from the valve core 3. The diameters of the top hole 53, the middle hole 51 and the bottom hole 52 increase in sequence.

[0026] A balancing hole 32 is arranged on the end face of the valve core 3 close to the ejector rod 4. One end of the balancing hole 32 is communicated with the bottom hole 52, and the other end of the balancing hole 32 is communicated with the second oil passage 31.

[0027] One end of the valve sleeve 1 contracts inwards to form a step surface 12. One end of the spring 2 is elastically connected to the valve core 3, and the other end of the spring 2 is elastically connected to the step surface 12.

[0028] One end of the spool 3 is provided with a blind hole 33 into which the spring 2 is inserted; the first oil passage 30 includes a first annular groove 34 on the outer peripheral surface of the spool 3, and a first through hole 35 is provided on the bottom surface of the first annular groove 34, and the first through hole 35 communicates with the blind hole 33; the second oil passage 31 includes a second annular groove 36 on the outer peripheral surface of the spool 3, and a second through hole 37 is provided on the bottom surface of the second annular groove 36, and the second through hole 37 communicates with the bottom surface of the blind hole 33.

[0029] The control method of the axial piston pump one-way control valve achieves the required overflow pressure of the one-way control valve by presetting the stiffness of the spring 2, that is, when the required high-pressure overflow pressure changes, the spring 2 with different stiffness can be replaced.

[0030] Working principle: When installed on an axial piston pump, the lower end of the valve sleeve 1 (i.e., the end where the spherical surface is located) is located outside the working cavity of the axial piston pump and forms an oil inlet, and other parts are inserted into the axial piston pump, including the first annular groove 34, the second annular groove 36, and the top hole 53 are all located in the working cavity of the axial piston pump.

[0031] In the initial state, under the elastic force of the spring 2, the spool 3 abuts against the lower end surface of the plug 5. At this time, the second annular groove 36 is located at the liquid replenishing hole passage 11. The working cavity is communicated with the valve sleeve 1 through the liquid replenishing hole passage 11, the second annular groove 36, the second through hole 37, and the blind hole 33 in sequence. And the first annular groove 34 is between the liquid replenishing hole passage 11 and the liquid discharge hole passage 10, and the first annular groove 34 is not communicated with the liquid replenishing hole passage 11. When the external oil enters from the lower end of the valve sleeve 1, the external oil smoothly enters the working cavity to replenish the working cavity. At this time, the one-way valve function of the one-way control valve is in the open state, and the oil flows unidirectionally into the working cavity.

[0032] As the axial piston pump works, when the oil pressure in the working cavity increases to a certain extent, the ejector rod 4 moves downward under the action of the oil pressure in the working cavity. The ejector rod 4 pushes the spool 3 to move downward against the spring force. When the spool 3 moves a certain distance, the second annular groove 36 is disconnected from the liquid replenishing hole passage 11, and the external oil cannot enter the working cavity. The one-way valve function of the one-way control valve is in the closed state, and the external oil cannot enter the working cavity. As the oil pressure in the working cavity continues to increase, the spring 2 is further compressed, and the spool 3 continues to move downward until the pressure in the working cavity reaches the set overflow pressure. The first annular groove 34 moves downward to communicate with the liquid discharge hole passage 10. The oil in the working cavity is discharged from the lower end of the valve sleeve 1 through the liquid discharge hole passage 10, the first annular groove 34, the first through hole 35, and the blind hole 33. The overflow valve function of the one-way control valve is opened, and the oil in the working cavity overflows to achieve pressure reduction.

[0033] In the initial state, the valve core 3 contacts the plug 5 under the action of the pressure F2 of the spring 2, and the plug 5 gives the valve core 3 a reaction force F1. The one-way control valve is in the position where the one-way valve function is opened. Then, the hydraulic pressure in the working chamber forms a force F3 on the push rod 4. The push rod 4 moves downward by a distance h under the force and acts on the valve core 3 with a pressure F4. The valve core 3 moves downward by a distance h under the pressure F4 of the push rod and acts on the spring with a pressure F5. The spring with a stiffness of K contracts by a length h under the action of the pressure F5. Under the action of F2 and F4, the valve core 3 is in the position where the overflow valve function is opened, and the high-pressure hydraulic oil is discharged from the working chamber. F1 = F2, F3 = F4 = F5.

[0034] Condition for closing the one-way valve function: the downward movement distance h of the valve core 3 ≥ the one-way valve orifice diameter D1 (i.e., the axial communication distance between the liquid replenishing hole passage 11 and the second annular groove 36);

[0035] Condition for opening the high-pressure overflow valve: the downward movement distance h of the valve core ≥ the distance L between the one-way valve orifice and the high-pressure overflow orifice (i.e., the distance between the first annular groove 34 and the liquid discharge hole passage 10).

Claims

1. Axial piston pump one-way control valve, characterized in that: It includes a valve sleeve (1), inside which there is a spool (3) connected in a sliding manner. On one side of the spool (3), there is a spring (2) connected to the valve sleeve (1). On the other side of the spool (3), there is a plug (5). The plug (5) is axially provided with a guide hole (50), and a push rod (4) is arranged in the guide hole (50). The side wall of the valve sleeve (1) is provided with a liquid discharge hole passage (10) and a liquid replenishment hole passage (11). The spool (3) is provided with an annular first oil passage (30) and an annular second oil passage (31). The radially inner sides of the first oil passage (30) and the second oil passage (31) are both communicated with the inner cavity of the valve sleeve (1). The radially outer side of the first oil passage (30) is located on the side wall of the spool (3) and is between the liquid discharge hole passage (10) and the liquid replenishment hole passage (11). The radially outer side of the second oil passage (31) is located on the side wall of the spool (3) and is communicated with the liquid replenishment hole passage (11). One end of the valve sleeve (1) contracts inward to form a step surface (12). One end of the spring (2) is elastically connected to the spool (3), and the other end of the spring (2) is elastically connected to the step surface (12). The guide hole (50) includes a middle hole (51) slidably connected to the push rod (4). One end of the middle hole (51) close to the spool (3) is provided with a bottom hole (52), and the end of the middle hole (51) far from the spool (3) is provided with a top hole (53). On the end surface of the spool (3) close to the push rod (4), there is a balance hole (32). One end of the balance hole (32) is communicated with the bottom hole (52), and the other end of the balance hole (32) is communicated with the second oil passage (31). One end of the spool (3) is provided with a blind hole (33) into which the spring (2) is inserted. The blind hole (33) is communicated with the inner cavity of the valve sleeve (1). The radially inner sides of the first oil passage (30) and the second oil passage (31) are both communicated with the blind hole (33).

2. The one-way control valve of the axial piston pump according to claim 1, characterized in that: The diameters of the top hole (53), the middle hole (51), and the bottom hole (52) increase in sequence.

3. The one-way control valve of the axial piston pump according to claim 1, characterized in that: The first oil passage (30) includes a first annular groove (34) located on the outer peripheral surface of the spool (3). A first through hole (35) is provided on the bottom surface of the first annular groove (34), and the first through hole (35) is communicated with the blind hole (33). The second oil passage (31) includes a second annular groove (36) located on the outer peripheral surface of the spool (3). A second through hole (37) is provided on the bottom surface of the second annular groove (36), and the second through hole (37) is communicated with the bottom surface of the blind hole (33).

4. The control method of the one-way control valve of the axial piston pump according to any one of claims 1 to 3, characterized in that: By presetting the stiffness of the spring (2), the overflow pressure of the required one-way control valve is achieved.

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