Lever balance mechanism

Abstract

The utility model belongs to the field of hydraulic plunger pump control technology application, and discloses a lever balance mechanism which comprises a valve body with a mounting cavity, a sealing opening at the bottom of the mounting cavity, a valve element in clearance fit with the valve body and arranged in the mounting cavity, a reset spring arranged at the bottom of the valve element, an ejector pin connected with the bottom of the valve element in a matched mode, and an adjusting seat arranged at the upper end of the ejector pin in a matched mode. The adjusting seat is connected with a supporting valve externally connected with a plunger pump; an adjusting screw rod is arranged above the adjusting seat, an elastic component is connected to the adjusting screw rod, and the elastic component is connected with the adjusting seat; along with the change of the tilt angle of a swash plate of a plunger pump externally connected with the adjusting seat, the valve element is controlled to move axially under the combined action of the reset spring, the valve element and the adjusting screw rod, and constant-power control is achieved. The structure of the constant-power control module of the plunger pump is simplified, the types of control parts are reduced, the manufacturing cost of the constant-power control module is reduced, and the problems of strict machining precision requirements, multiple types of parts and high manufacturing cost caused by a traditional constant-power control displacement feedback and spring force feedback mode are solved.

Description

Technical Field

[0001] This utility model relates to a lever balancing mechanism, belonging to the field of hydraulic plunger pump control technology application. Background Technology

[0002] Hydraulic piston pumps typically employ a constant power control method to limit power, which is determined by the input power of the piston pump. In the formula, P represents the load, Q represents the flow rate, and η t Let represent the overall efficiency, and p be the input power of the plunger pump. As the calculation formula shows, to achieve a constant input power for the plunger pump, ensuring that the input power of the plunger pump is always lower than the output power of the engine or motor under all load conditions, when the overall efficiency remains constant, as the load on the plunger pump increases, the output flow rate of the plunger pump must decrease synchronously to ensure that the input power of the plunger pump remains constant.

[0003] To achieve the aforementioned constant power control, traditional piston pumps employ displacement feedback or spring force feedback. While both of these structures can effectively achieve constant power control, their complex structures, numerous parts, and high precision requirements result in high manufacturing costs, limiting the development of constant power control methods in piston pump applications. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a lever balance mechanism that simplifies the structure of the constant power control module of the plunger pump, reduces the types of control parts, lowers the manufacturing cost of the constant power control module, and solves the problems of strict processing accuracy requirements, many types of parts, and high manufacturing costs caused by traditional constant power control displacement feedback and spring force feedback methods.

[0005] To address the aforementioned problems, this utility model provides a lever balancing mechanism, comprising a valve body with a mounting cavity, the bottom of which is sealed. Inside the mounting cavity is a valve core that is clearance-fitted with the valve body. A return spring is located at the bottom of the valve core. A pin is connected to the bottom of the valve core, and an adjusting seat is spherically fitted to the upper end of the pin. The adjusting seat is connected to a support valve of an external plunger pump and rotates along its connection point with the support valve. An adjusting screw is located above the adjusting seat, and an elastic component is connected to the adjusting screw, which is fitted to the adjusting seat. The adjusting seat has a raceway for the movement of an external roller. As the swashplate angle of the external plunger pump changes, the axial movement of the valve core is controlled by the combined action of the return spring, the valve core, and the adjusting screw, thereby adjusting the displacement of the plunger pump, i.e., achieving constant power control.

[0006] According to this utility model, the bottom of the mounting cavity of the valve body is threaded with a screw plug, and the reset spring is fixed by a first spring seat and a second spring seat. The lower end of the first spring seat is limited by the screw plug, and the upper end of the second spring seat is limited by the valve core through a spherical fit.

[0007] According to this utility model, the top surface of the valve core has a conical inner hole, the lower end spherical surface of the ejector pin is tangent to the conical inner hole of the valve core, and the upper end spherical surface of the ejector pin cooperates with the adjusting seat.

[0008] According to this utility model, further, the mating parts of the adjusting seat, the ejector pin, and the elastic component are all provided with concave spherical surfaces. The upper spherical surface of the ejector pin mates with the upper concave spherical surface, and the bottom of the elastic component mates with the lower concave spherical surface of the adjusting seat.

[0009] According to this utility model, the elastic component further includes a fourth spring seat disposed at the lower end of the spring, the fourth spring seat cooperating with the concave spherical surface of the adjusting seat located below.

[0010] According to this utility model, it further includes a support pin that penetrates the adjusting seat, and the two are fitted with a clearance, allowing the adjusting seat to rotate flexibly around the support pin; the support pin has a groove for installing an O-ring, the support pin is installed in the valve body, and is limited by a snap ring through a hole, and sealed by an O-ring.

[0011] According to this utility model, a fourth spring is further provided at the upper end of the spring, and the fourth spring seat cooperates with the spherical surface of the adjusting screw.

[0012] According to this utility model, it further includes a nut, which is threadedly locked onto the valve body, and the adjusting screw is threadedly locked onto the nut, which can adjust the preload of the spring.

[0013] According to this utility model, it further includes a nut, a sealing cap, and an O-ring disposed on the top of the valve body, which work together to seal the hydraulic oil of the preload adjustment structure.

[0014] According to this utility model, it further includes a spacer sleeve, which is interference-fitted into the valve body to support the support pin.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. Simplify the structure of the constant power control module for the plunger pump, reduce the types of control components, and lower the manufacturing cost of the constant power control module to solve the problems of strict machining accuracy requirements, many types of parts, and high manufacturing costs caused by traditional constant power control displacement feedback and spring force feedback methods.

[0017] 2. The constant power control structure of this utility model is simple;

[0018] 3. The parts of this utility model have low precision requirements and controllable manufacturing costs. Attached Figure Description

[0019] Figure 1 A schematic diagram of a lever balancing mechanism provided by this utility model;

[0020] Figure 2 A schematic diagram of a power control and adjustment module for a lever balancing mechanism provided by this utility model;

[0021] Figure 3 This is a schematic diagram of the installation of the hole retaining ring and spacer of this utility model;

[0022] Figure 4 This is a schematic diagram of the force distribution on the adjusting seat of this utility model;

[0023] Figure 5 A schematic diagram illustrating the installation and function of a lever balancing mechanism in a plunger pump assembly, as provided by this utility model.

[0024] Figure 6 This is a schematic diagram of the support valve structure.

[0025] Among them, 1-screw plug, 2-first spring seat, 3-reset spring, 4-second spring seat, 5-valve core, 6-ejector pin, 7-adjusting seat, 8-support pin, 9-third spring seat, 10-spring, 11-fourth spring seat, 12-nut, 13-nut, 14-adjusting screw, 15-sealing cap, 16-valve body, 17-spacer, 18-through hole, 19-hole retaining ring, 100-servo small cavity, 200-support valve, 300-large reset spring, 400-servo large cavity. Detailed Implementation

[0026] To make this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0027] Example

[0028] like Figure 1-6 As shown, the lever balancing mechanism provided by this utility model is locked onto the plunger pump by screws and three through holes 18 on the valve body. The roller in the support valve assembly inside the plunger pump is in contact with the raceway in the adjusting seat 7.

[0029] This utility model provides a lever balancing mechanism, comprising a valve body 16 with a mounting cavity, a screw plug 1 threadedly locked to the lower end of the mounting cavity of the valve body 16, a return spring 3 disposed in the mounting cavity, a valve core 5 installed in the valve body 16 with a small clearance fit, a pin 6 tangent to the conical surface of the inner hole of the valve core 5, an adjusting seat 7 fitted with the spherical surface of the upper end of the pin 6, a support pin 8 passing through the pin hole of the adjusting seat 7 and allowing the adjusting seat 7 to rotate flexibly, an adjusting screw 14 located above the adjusting seat 7, and a spring 10 disposed at the bottom of the adjusting screw 14 and fixed by a third spring seat 9 and a fourth spring seat 11. As the swashplate angle of the plunger pump connected to the adjusting seat 7 changes, the axial movement of the valve core 5 is controlled by the return spring 3, the spring 10, and the adjusting screw 14, thereby adjusting the displacement of the plunger pump, that is, achieving constant power control.

[0030] The adjusting seat 7 has concave spherical surfaces at the mating points with the ejector pin 6 and the fourth spring seat 11. The upper spherical surface of the ejector pin 6 mates with the upper concave spherical surface, and the bottom of the fourth spring seat 11 mates with the lower concave spherical surface of the adjusting seat 7. The adjusting seat 7 also has a raceway for the movement of the rollers.

[0031] The reset spring 3 is fixed by a first spring seat 2 located below it and a second spring seat 4 located above it. The lower end of the first spring seat 2 is limited by a screw plug 1, and the upper end of the second spring seat 4 is limited by a spherical fit with the valve core 5 installed in the mounting cavity.

[0032] The support pin 8 has a groove for installing an O-ring. The support pin 8 is installed in the valve body 16, and is limited by a retaining spring 19 through a hole, with an O-ring for sealing.

[0033] The nut 12 is threaded onto the valve body 16, and the adjusting screw 14 is threaded onto the nut 12. The adjusting screw 14 can adjust the preload of the spring 10.

[0034] Nut 13, sealing cap 15, and O-ring are used to seal the hydraulic oil in the preload adjustment structure.

[0035] The spacer 17 is installed in the valve body 16 via an interference fit, supporting the support pin 8. The principle of the constant power control variable of the lever balance mechanism provided by this utility model is as follows:

[0036] The piston pump load oil pressure P is connected to port P1 of the support valve 200 through an internal oil passage in the servo chamber 100, and also to port P2 of the lever balance mechanism through an oil passage. Point A in the support pin 8 serves as the fulcrum of the lever balance mechanism. The load oil pressure exerts a force F3 on the adjusting seat 7 at the support valve 200, with a lever arm of L2. The return spring 3 exerts a force F1 on the adjusting seat 7, with a lever arm of L1. The spring 10 exerts a force F2 on the adjusting seat 7, with a lever arm of L1. Therefore, the following lever balance relationship exists for the adjusting seat 7:

[0037] F1×L1+P×ΔS×L2=F2×L1. Due to the unequal diameters of the two steps of the valve core inside the support valve 200, there is an area difference ΔS. The force F3 formed by the load oil pressure P on the regulating seat 7 is ΔS×P, and the direction is towards the regulating seat 7. When the load oil pressure P is low, the pressure F3 on the roller is generated on the valve core of the support valve 200. The torque generated on the regulating seat 7 under the L2 lever arm is insufficient to overcome the torque formed by the return spring 3 and the spring 10 under the L1 lever arm. The regulating seat 7 does not rotate clockwise around the fulcrum A of the support pin 8, and the valve core 5 cannot move upward. The load oil waiting at the P1 port is blocked by the shoulder of the valve core 5 and cannot be connected to the oil passage of the servo large chamber 400. At this time, under the action of the compression force of its own large return spring 500 and the hydraulic pressure formed by the load oil in the servo small chamber 100, the swashplate swing angle of the plunger pump is the maximum, and the plunger pump outputs at the maximum flow rate.

[0038] When the load oil pressure P continues to rise, the force F3 exerted by the roller of the support valve 200 on the adjusting seat 7 increases. Under the lever arm L2, the torque formed is greater than the torque formed by the return spring 3 and the spring 10 under the lever arm L1. The adjusting seat 7 rotates clockwise around point A, the spring 10 is compressed, the return spring 3 is relaxed, the valve core 5 moves upward, and the load oil pressure P waiting at the lever balance structure is connected to the oil passage of the servo large chamber 400. The load oil enters the servo large chamber. At this time, the servo large chamber 400 and the servo small chamber 100 are simultaneously filled with hydraulic oil. Due to the area difference, the swashplate angle begins to decrease, and the output flow of the piston pump decreases. At this time, the desired effect is achieved. Constant power control, meaning that the higher the load pressure, the lower the output flow, is the qualitative analysis of the constant power control by the lever balancing mechanism.

[0039] like Figure 4As shown, when the swashplate angle decreases, the roller of the support valve 200 moves upward along the raceway of the adjusting seat 7. Assuming that the force F3 acting on the adjusting seat 7 is a fixed value under the same load oil pressure P, the upward movement of the roller reduces the force arm L2. Therefore, when L2 shrinks to a certain length, the resulting torque is insufficient to overcome the torque formed by the return spring 3 and spring 10 under the force arm L1. The valve core 5 then moves downward, disconnecting the load oil pressure P waiting at the lever balance structure from the servo large chamber 400 oil passage. Under the action of the servo small chamber 100 and the large return spring 300, the swashplate angle increases again. With the increased swashplate angle, the support valve 200 moves downward again, and the force arm L2 of F3 becomes longer, while spring 10 is released. Therefore, the torque formed by F3 overcomes the torque formed by the return spring 3 and spring 10 under the force arm L1, causing the valve core 5 to move upward and the plunger pump displacement to decrease again. This cycle repeats continuously. Therefore, it can be seen that in this lever balance structure, the plunger pump corresponds to a fixed flow output under a fixed load. It should be noted that by adjusting the screw 14, the preload of the spring 10 can be adjusted, which means that the constant power value of the plunger pump can be adjusted. This is the quantitative analysis of the constant power control by the lever balance mechanism.

Claims

1. A lever balancing mechanism, characterized by, The application relates to a valve body with a mounting cavity, the bottom of the mounting cavity is sealed, a valve core is arranged in the mounting cavity in a clearance fit mode, a reset spring is arranged at the bottom of the valve core, a thimble is connected to the bottom of the valve core in a fit mode, a spherical surface of the upper end of the thimble is connected to an adjusting seat in a fit mode, the adjusting seat is connected to a supporting valve of an external connecting plunger pump in a mode of rotation along a connecting point of the adjusting seat and the supporting valve, an adjusting screw is arranged above the adjusting seat, an elastic component is connected to the adjusting screw in a fit mode, the adjusting seat is provided with a rolling way for the movement of an external connecting roller, and the axial movement of the valve core is controlled under the joint action of the reset spring, the valve core and the adjusting screw, so that the displacement of the plunger pump is adjusted, that is, constant power control is realized.

2. A lever balancing mechanism as claimed in claim 1, characterized in that The bottom of the mounting cavity of the valve body is locked by a screw plug, the reset spring is fixed by a first spring seat and a second spring seat, the lower end of the first spring seat is limited by the screw plug, and the upper end of the second spring seat is limited by the valve core in a spherical surface fit mode.

3. A lever balancing mechanism as claimed in claim 1, wherein, The top surface of the valve core is provided with a conical inner hole, the lower end of the thimble is tangent to the conical inner hole of the valve core, and the upper end of the thimble is connected to the adjusting seat in a fit mode.

4. A lever balancing mechanism as claimed in claim 3, wherein, The adjusting seat is provided with an inner concave spherical surface at the fit positions of the thimble and the elastic component, the upper end of the thimble is connected to the upper inner concave spherical surface, and the bottom of the elastic component is connected to the lower inner concave spherical surface of the adjusting seat.

5. A lever balancing mechanism as claimed in claim 4, wherein, The elastic component comprises a fourth spring seat arranged at the lower end of the spring, and the fourth spring seat is connected to the lower inner concave spherical surface of the adjusting seat.

6. A lever balancing mechanism as claimed in claim 1, wherein, The application further comprises a supporting pin penetrating the adjusting seat and connected to the adjusting seat in a clearance fit mode, and the adjusting seat can rotate around the supporting pin; a groove for mounting an O-shaped ring is arranged on the supporting pin, the supporting pin is arranged in the valve body and limited by a clamping spring through a hole, and the O-shaped ring is sealed.

7. A lever balancing mechanism as claimed in claim 5, wherein, The upper end of the spring is provided with a fourth spring, and the fourth spring seat is connected to the spherical surface of the adjusting screw.

8. A lever balancing mechanism as claimed in claim 1, wherein, The application further comprises a screw cap, the screw cap is locked on the valve body in a threaded mode, the adjusting screw is locked on the screw cap in a threaded mode, and the adjusting screw can adjust the pre-tightening force of the spring.

9. A lever balancing mechanism as claimed in claim 8, wherein, The application further comprises a nut, a sealing cap and an O-shaped ring arranged at the top of the valve body, and the nut, the sealing cap and the O-shaped ring jointly seal the hydraulic oil of the adjusting pre-tightening structure.

10. A lever balancing mechanism as claimed in claim 6, wherein, The application further comprises a spacer sleeve, the spacer sleeve is arranged in the valve body in an interference fit mode and supports the supporting pin.

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