Emergency centering system for swing frame of closed axial plunger pump

Abstract

The utility model relates to the technical field of plunger pumps, in particular to a closed type axial plunger pump swing frame emergency centering system which comprises a closed type plunger pump, and the closed type plunger pump comprises a swing frame. Comprising a variable piston assembly, the variable piston assembly comprises a variable piston, a cavity a is formed in the left side of the variable piston, a cavity b is formed in the right side of the variable piston, and a piston spring abutting against the front end of the variable piston is arranged in the cavity b and connected with a swing frame; the cavity a is connected with an emergency middle return valve through an oil way; during electrification, control oil enters the cavity a through the emergency return valve, the variable piston is pushed to compress the piston spring rightwards, and the swing frame is driven to rotate; when power is cut off, control oil does not pass through the emergency return valve, and the piston spring pushes the variable piston leftwards to drive the swing frame to return to the zero position. Emergency centering of the swing frame is achieved in a brand new mode, so that the stability and safety of a vehicle hydraulic system under the braking working condition are optimized, and the service life of the vehicle hydraulic system is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of plunger pump technology, specifically a closed axial plunger pump swing arm emergency return system. Background Technology

[0002] Closed-type axial piston pumps are a type of positive displacement hydraulic pump. Due to their compact structure, small radial dimensions, and low moment of inertia, they are widely used in agricultural machinery, engineering machinery, metallurgy, aviation and other fields.

[0003] Closed-loop axial piston pumps typically use high-pressure hydraulic fluid to control the rotation of a swing arm from zero degrees to a certain angle, thereby increasing the pump's displacement. When used in vehicle operation, the swing arm needs to be returned to zero during braking to reduce the pressure shock on the hydraulic system and shorten the braking distance.

[0004] Currently, the common emergency return mechanism for the swing arm in closed-loop axial piston pumps returns the swing arm to its zero position by depressurizing the control oil. However, this method can result in incomplete depressurization, leading to situations where the swing arm cannot fully return to zero or returns slowly under certain operating conditions. This ultimately causes excessive pressure surges in the vehicle's hydraulic system during braking, reducing the system's lifespan, increasing braking distance, and decreasing safety. Therefore, considering the stability and safety of the vehicle's hydraulic system, it is necessary to design a novel emergency return mechanism for the swing arm to overcome the shortcomings of the current technology. Summary of the Invention

[0005] This invention provides an emergency return-to-center system for a closed-loop axial piston pump swing arm, aiming to solve the technical problem mentioned in the background art: existing emergency return-to-center mechanisms for closed-loop axial piston pump swing arms, which rely on depressurizing control oil to return the swing arm to the zero position, often result in incomplete depressurization, leading to the swing arm failing to return to center under certain operating conditions. The emergency return-to-center system for a closed-loop axial piston pump swing arm proposed in this invention achieves emergency return-to-center of the swing arm through a novel method, thereby optimizing the stability and safety of the vehicle's hydraulic system under braking conditions and extending the service life of the vehicle's hydraulic system. Furthermore, this invention provides a new structural design concept for the displacement control of closed-loop piston pumps.

[0006] This utility model provides the following technical solution to achieve the above objectives:

[0007] An emergency return-to-center system for a closed-loop axial piston pump includes a closed-loop piston pump and a swing frame; it also includes a variable piston assembly, which includes a variable piston. The left side of the variable piston is chamber a, and the right side is chamber b. A piston spring is provided in chamber b, which abuts against the front end of the variable piston. The piston spring is connected to the swing frame. Chamber a is connected to an emergency return-to-center valve oil circuit. When energized, control oil enters chamber a through the emergency return-to-center valve, pushing the variable piston to the right to compress the piston spring and causing the swing frame to rotate. When de-energized, no control oil flows through the emergency return-to-center valve, and the piston spring pushes the variable piston to the left, causing the swing frame to return to the zero position.

[0008] In the aforementioned closed-type axial piston pump swing frame emergency return system, the emergency return valve includes a valve sleeve, in which a valve core is movably disposed in the left and right directions; the emergency return valve has an X2 port at the right end, and an X1 port and a T port radially disposed on the right side, with the T port located to the left of the X1 port; when energized, the valve core moves to the right, the X1 port and the X2 port are connected, and the control oil flows through the X1 port to the X2 port and then to chamber a; when de-energized, the valve core moves to the left, the X1 port and the X2 port are no longer connected, and the X1 port is connected to the T port.

[0009] In the aforementioned closed axial piston pump swing frame emergency return system, an electromagnet push rod is provided on the left side of the valve core, a spring retaining ring is provided on the outside of the valve core, and a spring seat is provided on the right side of the spring retaining ring, which is fitted onto the outside of the valve core. A spring fitted onto the valve core is installed on the spring seat.

[0010] In the aforementioned closed axial piston pump swing frame emergency return system, the valve core is provided with an oil circuit conversion groove around the X1 port and the T port; when the power is off, the X1 port and the T port are connected through the oil circuit conversion groove, and the end of the valve core blocks the X2 port; when the power is on, the valve core moves to the right, the valve core blocks the T port, and the X2 port is connected to the X1 port through the oil circuit conversion groove.

[0011] In the aforementioned closed-type axial piston pump swing arm emergency return system, the T-port oil circuit is connected to the oil tank.

[0012] In the aforementioned closed-loop axial piston pump swing arm emergency return system, the closed-loop piston pump is connected to the input motor shaft.

[0013] Compared with the prior art, the closed-loop axial piston pump swing arm emergency return system provided by this utility model has the following beneficial effects:

[0014] This invention achieves zero-flow output of the closed-loop piston pump by directly cutting off the pressure oil source controlling the rotation of the closed-loop pump swing arm, allowing the swing arm to return to the zero position. This process is less prone to problems such as the swing arm failing to return to the zero position completely or returning to the zero position slowly, thus optimizing the stability and safety of the vehicle hydraulic system under braking conditions and improving the service life of the vehicle hydraulic system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the hydraulic system of this utility model in the state of de-energization of the emergency return valve electromagnet;

[0016] Figure 2 This is a schematic diagram of the hydraulic system of this utility model in the state of energizing the electromagnet of the emergency return valve;

[0017] Figure 3 Schematic cross-section of the emergency return valve Figure 1 ;

[0018] Figure 4 Schematic cross-section of the emergency return valve Figure 2 ;

[0019] Reference numerals: 1-oil tank, 2-emergency return valve, 3-variable piston assembly, 4-closed plunger pump, 5-input motor shaft, 6-valve sleeve, 7-valve core, 8-spring, 9-spring seat, 10-spring retaining ring, 11-electromagnet push rod, 12-variable piston, 13-piston spring, 14-oil circuit conversion groove. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0021] Example. An emergency return-to-center system for a closed-loop axial piston pump swing arm, structural reference. Figure 1-4 As shown, the system includes a closed-loop piston pump 4, which includes a swing arm; a variable piston assembly 3, which includes a variable piston 12. The left side of the variable piston 12 is chamber a, and the right side is chamber b. Chamber b is provided with a piston spring 13 that abuts against the front end of the variable piston 12. The piston spring 13 is connected to the swing arm; chamber a is connected to the emergency return valve 2 oil circuit; when energized, control oil enters chamber a through the emergency return valve 2, pushing the variable piston 12 to the right to compress the piston spring 13, thereby rotating the swing arm; when de-energized, no control oil passes through the emergency return valve 2, and the piston spring 13 pushes the variable piston 12 to the left, causing the swing arm to return to the zero position.

[0022] The emergency return valve 2 includes a valve sleeve 6, in which a valve core 7 is movably disposed in the left and right directions; the emergency return valve 2 has an X2 port at the right end, and an X1 port and a T port radially disposed on the right side, with the T port located to the left of the X1 port; when energized, the valve core 7 moves to the right, and the X1 port and the X2 port are connected, and the control oil flows through the X1 port to the X2 port and then to the a chamber; when de-energized, the valve core 7 moves to the left, and the X1 port and the X2 port are no longer connected, and the X1 port is connected to the T port.

[0023] The aforementioned on / off state of the emergency return valve 2 is preferably achieved through the following structure: An electromagnet push rod 11 is provided on the left side of the valve core 7, a spring retaining ring 10 is provided on the outer side of the valve core 7, and a spring seat 9 is provided on the right side of the spring retaining ring 10, which is fitted onto the outer side of the valve core 7. A spring 8, fitted onto the valve core 7, is mounted on the spring seat 9. With this structure, in the initial state, the spring 8, via the spring seat 9 and the spring retaining ring 10, holds the valve core 7 against the leftmost position of the emergency return valve 2; when the emergency return valve 2 is energized, the electromagnet push rod 11 pushes the valve core 7 to the right; after de-energization, the spring 8 pushes the valve core 7 back to the left.

[0024] The oil circuit switching of the aforementioned emergency return valve 2 is preferably achieved through the following structure: an oil circuit switching groove 14 is arranged around the X1 port and the T port on the valve core 7; when the power is off, the X1 port and the T port are connected through the oil circuit switching groove 14, and the end of the valve core 7 blocks the X2 port; when the power is on, the valve core 7 moves to the right, the valve core 7 blocks the T port, and the X2 port is connected to the X1 port through the oil circuit switching groove 14.

[0025] Similar to the application of closed-loop axial piston pumps in vehicles in the background art, this system is also used for vehicle control. In application, the T-port oil circuit is connected to the oil tank 1; the closed-loop piston pump 4 is connected to the input motor shaft 5; with this arrangement...

[0026] When the electromagnet of the emergency return control valve is energized, the electromagnet's push rod pushes the valve core of the emergency return valve to the right, connecting ports X1 and X2. Control oil from port X flows through port X1 to port X2, and finally to chamber a of the variable piston, pushing the variable piston and compressing the spring. Simultaneously, the variable piston's movement to the right rotates the swing arm of the closed-loop piston pump to a certain angle. At this time, the closed-loop piston pump outputs pressurized oil to drive the motor, providing power for vehicle movement. When the vehicle needs to brake, the electromagnet of the emergency return valve is de-energized, the electromagnet's push rod retracts, and the valve core of the emergency return valve moves to the left under the spring force. Ports X1 and X2 are no longer connected, and port X1 connects to port T. The variable piston moves to the left under the spring force, depressurizing the control oil in chamber a of the variable piston. Simultaneously, the variable piston's leftward movement returns the swing arm of the closed-loop pump to the zero position, the closed-loop pump stops outputting pressurized oil, and the vehicle loses its power source and stops moving.

[0027] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and concept of this application, should be included within the scope of protection of this application.

Claims

1. A swing frame emergency return system for a closed axial piston pump, comprising a closed piston pump (4) comprising a swing frame, characterized in that: The variable piston assembly (3) comprises a variable piston (12), the left side of the variable piston (12) is an a cavity, the right side is a b cavity, the b cavity is provided with a piston spring (13) abutting against the front end of the variable piston (12), the piston spring (13) is connected with a swing frame; the a cavity is connected with an emergency centering valve (2) oil circuit; when powered, the control oil enters the a cavity through the emergency centering valve (2), pushes the variable piston (12) to compress the piston spring (13) to the right, and drives the swing frame to rotate; when powered off, the control oil does not pass through the emergency centering valve (2), the piston spring (13) pushes the variable piston (12) to the left to drive the swing frame to return to zero position.

2. The closed-type axial piston pump swing bracket emergency return system according to claim 1, characterized in that: The emergency centering valve (2) comprises a valve sleeve (6), and a valve core (7) is movably arranged in the valve sleeve (6); the right end of the emergency centering valve (2) is provided with an X2 port, the right part is radially provided with an X1 port and a T port, and the T port is located on the left side of the X1 port; when powered, the valve core (7) moves to the right, the X1 port and the X2 port are communicated, the control oil flows to the a cavity through the X1 port and the X2 port; when powered off, the valve core (7) moves to the left, the X1 port and the X2 port are no longer communicated, and the X1 port is communicated with the T port.

3. The closed-type axial piston pump swing frame emergency return system according to claim 2, characterized by: The left side of the valve core (7) is provided with an electromagnet top rod (11), the outer side of the valve core (7) is provided with a spring retainer ring (10), the right side of the spring retainer ring (10) is provided with a spring seat (9) sleeved on the outer side of the valve core (7), and the spring seat (9) is provided with a spring (8) sleeved on the valve core (7).

4. A closed axial piston pump swing frame emergency return system according to claim 2 or 3, characterized in that: The valve core (7) is provided with an oil circuit conversion groove (14) around the X1 port and the T port; when powered off, the X1 port and the T port are communicated through the oil circuit conversion groove (14), and the end of the valve core (7) blocks the X2 port; when powered, the valve core (7) moves to the right, the valve core (7) blocks the T port, and the X2 port is communicated with the X1 port through the oil circuit conversion groove (14).

5. The closed-type axial piston pump swing frame emergency return system according to claim 2, characterized by: The T port is connected with an oil tank (1).

6. The closed-type axial piston pump swing frame emergency return system according to claim 1, characterized by: The closed plunger pump (4) is connected with an input motor shaft (5).

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