Flow regulation mechanism of variable piston pump

Abstract

The present invention discloses a flow regulating mechanism for a variable displacement plunger pump, belonging to the field of engineering machinery. The mechanism comprises a main valve body, a main pump regulator, a variable displacement piston, a minimum displacement limiter, and a maximum displacement limiter. The maximum displacement limiter comprises a secondary displacement adjustment screw, a locking nut A, a locking nut B, a return spring, a primary displacement adjustment valve body, and a limit valve core. The secondary displacement adjustment screw is connected to the inner cavity port of the primary displacement adjustment valve body, a limit valve core is disposed within the inner cavity of the primary displacement adjustment valve body, and a return spring is disposed between the secondary displacement adjustment screw and the limit valve core. The locking nut A is externally threadedly connected to the secondary displacement adjustment screw, and the locking nut B is externally threadedly connected to the primary displacement adjustment valve body. An oil inlet channel A is provided on the secondary displacement adjustment screw, and an oil inlet channel B is provided within the limit valve core. The present invention achieves two-stage maximum displacement adjustment of the variable displacement pump through a two-stage adjustable maximum displacement limiter.

Description

Technical Field

[0001] The present invention belongs to the field of engineering machinery, and in particular relates to a flow regulating mechanism of a variable plunger pump. Background Art

[0002] With the rapid growth of the social economy and the rapid development of science and technology, production efficiency is also continuously improving. In the field of engineering machinery applications, the market and the control capabilities of the main pump have put forward increasingly higher requirements. The main pump is developing in the direction of intelligence and electronic control. Under the regulation mode of constant power, constant pressure, constant flow, etc., the adjustment of displacement requires a faster control solution.

[0003] Figure 1 It is a commonly used flow regulation structure for variable piston pumps used in engineering machinery. The position of the variable piston is adjusted through the main pump regulator. The displacement of the variable piston drives the angle of the main pump's swash plate to adjust the main pump's displacement. The maximum displacement of the variable piston is limited by the two limit screws on the left and right, which determines the maximum and minimum displacement of the main pump. The limit screws can be adjusted manually to adjust the flow range of the main pump. Due to the characteristics of the existing variable mechanism of the variable piston pump, it is not convenient to make secondary adjustments to the maximum and minimum displacement of the main pump after the limit screws are set. However, when engineering machinery is working, it may require a larger displacement under different working conditions to improve operating efficiency. The existing main pump structure brings two significant problems: first, the maximum displacement is not convenient to adjust, and second, the main pump is not convenient to recover after adjustment. This problem urgently needs a new structure to improve. Summary of the Invention

[0004] The object of the present invention is to provide a flow regulating mechanism for a variable piston pump to overcome the defects in the prior art that the maximum displacement of the flow regulating mechanism of the variable piston pump is inconvenient to adjust and the main pump is inconvenient to recover after adjustment.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A flow regulating mechanism of a variable piston pump comprises a main valve body, a main pump regulator, a variable piston, a minimum displacement limiting mechanism and a maximum displacement limiting mechanism, the main pump regulator is connected to the variable piston, the variable piston is arranged in the main valve body cavity, the minimum displacement limiting mechanism and the maximum displacement limiting mechanism are respectively arranged at both ends of the main valve body, the maximum displacement limiting mechanism comprises a secondary displacement adjusting screw, a locking nut A, a locking nut B, a reset spring, a primary displacement adjusting valve body, and a limiting valve core, the secondary displacement adjusting screw is connected to the primary displacement adjusting valve body cavity port, the primary displacement adjusting valve body cavity is provided with a limiting valve core, the reset spring is arranged between the secondary displacement adjusting screw and the limiting valve core, the locking nut A is connected to the secondary displacement adjusting screw external thread, the locking nut B is connected to the primary displacement adjusting valve body external thread, the secondary displacement adjusting screw is provided with an oil inlet channel A, and the limiting valve core is provided with an oil inlet channel B.

[0007] Furthermore, a maximum displacement limit block is provided between the variable displacement piston in the inner cavity of the main valve body and the limit valve core.

[0008] Furthermore, the minimum displacement limiting mechanism includes a minimum displacement limiting block, a minimum displacement limiting screw, and a locking nut C. The minimum displacement limiting block is connected to the minimum displacement limiting screw, and the minimum displacement limiting screw is threadedly connected to the locking nut C.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a method for adjusting the two-stage maximum displacement of a variable pump through the application of a two-stage adjustable maximum displacement limit mechanism. When the left side of the variable mechanism is not supplied with pressure oil, the pump has a first-level maximum displacement; when the left side of the variable mechanism is supplied with pressure oil, a second-level maximum displacement is obtained. When the engineering machinery encounters a large flow and high working speed working condition, the oil supply of the limit mechanism is opened, and it can quickly switch to the second-level maximum displacement working mode; when the work is completed, the oil supply of the limit mechanism is cut off, and the working condition of the ordinary first-level maximum displacement is restored. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram of the flow regulating mechanism of a variable plunger pump in the prior art;

[0011] Figure 2 It is a structural schematic diagram of the present invention.

[0012] In the figure: 1. Main valve body; 2. Main pump regulator; 3. Secondary displacement adjustment screw; 4. Locking nut A; 5. Locking nut B; 6. Return spring; 7. Primary displacement adjustment valve body; 8. Limit valve core; 9. Maximum displacement limit block; 10. Variable piston; 11. Main pump; 12. Minimum displacement limit block; 13. Minimum displacement limit screw; 14. Locking nut C; 15. Oil inlet channel A; 16. Oil inlet channel B. DETAILED DESCRIPTION

[0013] The present invention will be further described below with reference to the accompanying drawings.

[0014] like Figure 2 As shown, the flow regulation mechanism of the variable displacement plunger pump described in the present invention includes a main valve body 1, a main pump regulator 2, a variable displacement piston 10, a minimum displacement limiter mechanism, and a maximum displacement limiter mechanism. The main pump regulator 2 is connected to the variable displacement piston 10, which is disposed within the inner cavity of the main valve body 1. The minimum displacement limiter mechanism and the maximum displacement limiter mechanism are respectively disposed at both ends of the main valve body 1. The position of the variable displacement piston 10 is adjusted by the main pump regulator 2. The displacement of the variable displacement piston 10 drives the swash plate of the main pump 11 to adjust its angle, thereby adjusting the displacement of the main pump 11. The maximum displacement of the variable displacement piston 10 is limited by the minimum displacement limiter mechanism and the maximum displacement limiter mechanism, determining the maximum and minimum displacements of the main pump 11.

[0015] Specifically, the maximum displacement limiting mechanism includes a secondary displacement adjusting screw 3, a locking nut A4, a locking nut B5, a reset spring 6, a primary displacement adjusting valve body 7, and a limit valve core 8. The secondary displacement adjusting screw 3 is connected to the inner cavity port of the primary displacement adjusting valve body 7, and a limit valve core 8 is set in the inner cavity of the primary displacement adjusting valve body 7. The reset spring 6 is set between the secondary displacement adjusting screw 3 and the limit valve core 8. The locking nut A4 is externally threadedly connected to the secondary displacement adjusting screw 3, and the locking nut B5 is externally threadedly connected to the primary displacement adjusting valve body 7. One end of the limit valve core 8 extends out of the outside of the primary displacement adjusting valve body 7 and extends into the inner cavity of the main valve body 1. The secondary displacement adjusting screw 3 is provided with an oil inlet channel A15, and the limit valve core 8 is provided with an oil inlet channel B16.

[0016] Furthermore, a maximum displacement limit block 9 is provided between the variable piston 10 in the main valve body 1 and the limit valve core 8. The maximum displacement limit block 9 is used to limit the left position of the variable piston 10 and seal the hydraulic oil in the main valve body 1 cavity.

[0017] The function of the secondary displacement adjustment screw 3 is to determine the displacement of the leftmost side of the limit valve core 8; the function of the locking nut A4 is to adjust the displacement of the secondary displacement adjustment screw 3; the function of the locking nut B5 is to adjust the displacement of the primary displacement adjustment valve body 7; the function of the return spring 6 is to provide a rightward elastic force acting on the limit valve core 8 to lock the position of the maximum displacement limit block 9 and the variable piston 10; the function of the primary displacement adjustment valve body 7 is to limit the position of the maximum displacement limit block 9 and the variable piston 10; the variable piston 10 determines the primary maximum displacement of the main pump 11; the function of the limit valve core 8 is to determine the leftmost position of the maximum displacement limit block 9 and the variable piston 10, which is a direct limiting structure.

[0018] When the oil inlet channel A15 and the oil inlet channel B16 on the left side of the flow regulating mechanism are not connected with pressurized oil, the limit valve core 8 has a fixed position under the action of the return spring 6, limiting the maximum displacement of the left side of the variable piston 10. At this time, the main pump 11 has a first-level maximum displacement; when the left side of the variable mechanism is supplied with pressurized oil, the limit valve core 8 moves to the left under the action of the spring force and the hydraulic oil pressure until it reaches the limit of the second-level displacement adjustment screw 3. At this time, the displacement of the main pump 11 increases, and a second-level maximum displacement is obtained.

[0019] Furthermore, the minimum displacement limiting mechanism includes a minimum displacement limiting block 12, a minimum displacement limiting screw 13, and a locking nut C14. The minimum displacement limiting block 12 is connected to the minimum displacement limiting screw 13, and the minimum displacement limiting screw 13 is threadedly connected to the locking nut C14.

[0020] The minimum displacement limit of the flow regulating mechanism uses a minimum displacement limit block 12, a minimum displacement limit screw 13, and a locking nut C14 to limit the position of the variable piston 10, thereby limiting the minimum displacement of the main pump 11. The function of the minimum displacement limit block 12 is to limit the right side position of the variable piston 10 and the sealing of the hydraulic oil in the inner cavity of the main valve body 1.

[0021] Two-stage displacement adjustment method for maximum displacement: For first-stage displacement adjustment, loosen the locking nut B5, adjust the first-stage displacement adjustment valve body 7, screw the locking nut B5 clockwise into the first-stage displacement adjustment valve body 7 to reduce the displacement, loosen the first-stage displacement adjustment valve body 7 counterclockwise to increase the displacement, after the adjustment is completed, tighten the locking nut B5 to complete the adjustment; for second-stage displacement adjustment, loosen the locking nut A4 to adjust the second-stage displacement adjustment screw 3, screw in the second-stage displacement adjustment screw 3 clockwise to reduce the displacement, loosen the second-stage displacement adjustment screw 3 counterclockwise to increase the displacement, after the adjustment is completed, tighten the locking nut A4 to complete the adjustment.

[0022] Manual adjustment method of minimum displacement: Loosen the locking nut C14 and adjust the minimum displacement limit screw 13. Screw in the minimum displacement limit screw 13 clockwise to increase the displacement. Loosen the minimum displacement limit screw 13 counterclockwise to reduce the displacement. After the adjustment is completed, tighten the locking nut C14 to complete the adjustment.

Claims

1. A flow regulating method for a variable piston pump, wherein the flow regulating mechanism of the variable piston pump comprises a main valve body (1), a main pump regulator (2), a variable piston (10), a minimum displacement limit mechanism and a maximum displacement limit mechanism, wherein the main pump regulator (2) is connected to the variable piston (10), the variable piston (10) is arranged in the inner cavity of the main valve body (1), and the minimum displacement limit mechanism and the maximum displacement limit mechanism are respectively arranged at both ends of the main valve body (1), characterized in that: The maximum displacement limiting mechanism comprises a secondary displacement adjusting screw (3), a locking nut A (4), a locking nut B (5), a reset spring (6), a primary displacement adjusting valve body (7), and a limit valve core (8); the secondary displacement adjusting screw (3) is connected to the inner cavity port of the primary displacement adjusting valve body (7); the limit valve core (8) is provided in the inner cavity of the primary displacement adjusting valve body (7); the reset spring (6) is provided between the secondary displacement adjusting screw (3) and the limit valve core (8); the locking nut A (4) is connected to the external thread of the secondary displacement adjusting screw (3); the locking nut B (5) is connected to the external thread of the primary displacement adjusting valve body (7); the secondary displacement adjusting screw (3) is provided with an oil inlet channel A (15); and the limit valve core (8) is provided with an oil inlet channel B (16); A maximum displacement limit block (9) is provided between the variable piston (10) in the inner cavity of the main valve body (1) and the limit valve core (8); The minimum displacement limiting mechanism comprises a minimum displacement limiting block (12), a minimum displacement limiting screw (13), and a locking nut C (14); the minimum displacement limiting block (12) is connected to the minimum displacement limiting screw (13), and the minimum displacement limiting screw (13) is threadedly connected to the locking nut C (14); The left side position of the variable piston (10) is limited by the maximum displacement limit block (9) and the hydraulic oil in the inner cavity of the main valve body (1) is sealed; The displacement of the limit valve core (8) to the leftmost side is determined by the secondary displacement adjustment screw (3), and the displacement of the secondary displacement adjustment screw (3) is adjusted by the locking nut A (4); the displacement of the primary displacement adjustment valve body (7) is adjusted by the locking nut B (5); a rightward elastic force is provided on the limit valve core (8) by the return spring (6), locking the position of the maximum displacement limit block (9) and the variable piston (10); the position of the maximum displacement limit block (9) and the variable piston (10) is limited by the primary displacement adjustment valve body (7); the primary maximum displacement of the main pump (11) is determined by the variable piston; the leftmost position of the maximum displacement limit block (9) and the variable piston (10) is directly determined by the limit valve core (8); When the oil inlet channel A (15) and the oil inlet channel B (16) on the left side of the flow regulating mechanism are not supplied with pressurized oil, the limit valve core (8) has a fixed position under the action of the return spring (6), limiting the maximum displacement of the left side of the variable piston (10). At this time, the main pump (11) has a first-stage maximum displacement. When the left side of the variable mechanism is supplied with pressurized oil, the limit valve core (8) moves leftward under the action of the spring force and the hydraulic oil pressure until it reaches the limit position of the second-stage displacement adjustment screw (3). At this time, the displacement of the main pump (11) increases, and a second-stage maximum displacement is obtained. The two-stage displacement adjustment method of the maximum displacement is as follows: for the first-stage displacement adjustment, loosen the locking nut B (5), adjust the first-stage displacement adjustment valve body (7), screw the locking nut B (5) clockwise into the first-stage displacement adjustment valve body (7), the displacement decreases, loosen the first-stage displacement adjustment valve body (7) counterclockwise, the displacement increases, after the adjustment is completed, tighten the locking nut B (5), and the adjustment is completed; for the second-stage displacement adjustment, loosen the locking nut A (4), adjust the second-stage displacement adjustment screw (3), screw the second-stage displacement adjustment screw (3) clockwise, the displacement decreases, loosen the second-stage displacement adjustment screw (3) counterclockwise, the displacement increases, after the adjustment is completed, tighten the locking nut A (4), and the adjustment is completed; Manual adjustment method of minimum displacement: Loosen the locking nut C (14) and adjust the minimum displacement limit screw (13). Screw in the minimum displacement limit screw (13) clockwise to increase the displacement. Loosen the minimum displacement limit screw (13) counterclockwise to reduce the displacement. After the adjustment is completed, tighten the locking nut C (14) to complete the adjustment.

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