A method for matching design of an additional angle of an aviation hydraulic pump swash plate and a oil distribution plate

Abstract

The application discloses a kind of aviation hydraulic pump swash plate additional angle and oil distribution plate matching design method, by changing the size of oil window of oil distribution plate and the size of unloading groove (6) on oil window, make oil distribution plate and swash plate additional angle match;Swash plate swing angle is recorded as α, swash plate additional angle is recorded as β, the waist-shaped hole of aviation hydraulic pump rotor is recorded as l, and the radius of waist-shaped hole distribution circle of rotor is recorded as R;According to the right-hand rule, establish basic coordinate system, define the plane through swash plate rotation axis (5) and parallel to swash plate plane as swash plate reference surface, with the main shaft axis of aviation hydraulic pump as x axis, the main shaft axis of aviation hydraulic pump extends from head to tail as the positive direction of x axis, with swash plate rotation axis as y axis, determine Z axis.The application has the advantages of improving the functional performance of hydraulic pump.

Description

Technical Field

[0001] This invention belongs to the field of aviation hydraulic pumps, and particularly relates to a design method for matching the swashplate additional angle and the distributor plate of an aviation hydraulic pump. Background Technology

[0002] Aviation hydraulic pumps generally employ constant-pressure variable displacement piston pumps. Due to their compact structure, high power density, low noise, and good dynamic characteristics, constant-pressure variable displacement piston pumps serve as the main pump in aviation hydraulic systems. To increase power density, reduce outlet pressure pulsation, and improve control characteristics, aviation hydraulic pumps have an additional angle on the swashplate plane. The size of this additional angle is matched with the design of the distributor plate. If the swashplate additional angle does not match the distributor plate structure, it will lead to several problems: first, the hydraulic pump will experience inlet discharge and outlet suction, reducing its volumetric efficiency; second, the pre-pressurization and pre-depressurization effects will be reduced when the piston chamber is in the distributor plate transition zone, increasing outlet pressure pulsation; and third, when the hydraulic pump piston chamber is at the bottom dead center of the distributor plate transition zone, a "pressure buildup" phenomenon will occur, causing the hydraulic pump components to be subjected to a periodic impact force, making the rotor prone to overturning and resulting in unstable pump operation. Simultaneously, it will alter the swashplate torque, leading to unstable variable displacement control and affecting the reliability and lifespan of the hydraulic pump. As aviation hydraulic pumps evolve towards high-speed, heavy-duty operation, the problems caused by the mismatch between the swashplate additional angle and the distributor plate structure are becoming increasingly prominent, severely impacting the pump's performance and consequently reducing the reliability of airborne hydraulic systems. Therefore, the design of the swashplate additional angle and distributor plate structure is crucial for improving the performance of aviation hydraulic pumps and enhancing the reliability of airborne hydraulic systems. Summary of the Invention

[0003] The purpose of this invention is to provide a design method for matching the swashplate additional angle with the distributor plate in an aviation hydraulic pump. This invention has the advantage of improving the functional performance of the hydraulic pump.

[0004] The technical solution of the present invention is a design method for matching the additional angle of the swashplate and the oil distribution plate of an aviation hydraulic pump. By changing the size of the oil window on the oil distribution plate and the size of the unloading groove on the oil window, the additional angle of the oil distribution plate and the swashplate are matched.

[0005] In the aforementioned design method for matching the swashplate additional angle and the distributor plate of the aviation hydraulic pump, the swashplate swing angle is denoted as α, the swashplate additional angle is denoted as β, the length of the rotor waist-shaped hole of the aviation hydraulic pump is denoted as l, and the radius of the rotor waist-shaped hole distribution circle is denoted as R.

[0006] A basic coordinate system is established based on the right-hand rule. The plane that passes through the axis of rotation of the swashplate and is parallel to the plane of the swashplate is defined as the swashplate reference plane. The axis of rotation of the main shaft of the aviation hydraulic pump is taken as the x-axis, and the direction from the extension end of the main shaft of the aviation hydraulic pump to the tail end is the positive x-axis. The axis of rotation of the swashplate is taken as the y-axis, and the Z-axis is determined.

[0007] The angle between the unloading groove of the oil window in the high-pressure zone and the z-axis is denoted as θ1, the angle between the unloading groove of the oil window in the low-pressure zone and the z-axis is denoted as θ2, the angle between the oil window in the low-pressure zone and the z-axis is denoted as φ1, and the angle between the oil window in the high-pressure zone and the z-axis is denoted as φ4.

[0008] The following conditions must be met simultaneously.

[0009]

[0010]

[0011] Compared with existing technologies, this invention establishes mathematical relationships between the swashplate angle, the radius of the oil distribution circle of the distributor plate, the length of the unloading groove, and the included angle of the transition zone, based on the actual working conditions of aviation hydraulic pumps and the motion law of the sliding shoe-plunger assembly. It proposes a matching design method for the swashplate additional angle and the distributor plate, thereby scientifically guiding the design of the swashplate additional angle and the distributor plate, ensuring that the hydraulic pump swashplate additional angle and the distributor plate match under corresponding working conditions, improving the functional performance of aviation hydraulic pumps and enhancing the reliability of airborne hydraulic systems. Attached Figure Description

[0012] Figure 1 This is a diagram showing the additional angle of the swashplate.

[0013] Figure 2 This is a schematic diagram showing the motion trajectory of the sliding track-plunger assembly and the corresponding structure of the oil distributor.

[0014] Figure 3 It is a graph showing the change in swashplate deflection angle;

[0015] Figure 4 These are two schematic diagrams illustrating situations where the swashplate additional angle does not match the oil separator plate.

[0016] Figure 5 This is a schematic diagram of the rotor structure.

[0017] Figure 6 This is a schematic diagram of the oil separator structure.

[0018] The markings in the attached diagram are: 1-swashplate; 2-slipper; 3-plunger; 4-deflection shaft; 5-swashplate rotation axis; 6-unloading groove. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0020] Example. A design method for matching the swashplate additional angle of an aviation hydraulic pump with the distributor plate, such as... Figure 1As shown, a basic coordinate system is established according to the right-hand rule. The plane passing through the swashplate rotation axis 5 and parallel to the swashplate plane is defined as the swashplate reference plane. The axis of the inner shaft (i.e., the main shaft of the aviation hydraulic pump) is the x-axis, the direction from the inner shaft extension end to the tail end is the positive x-axis, and the swashplate rotation axis is the y-axis. If the swashplate 1 has no additional angle, when the swashplate 1 swings, the upper and lower dead points of the sliding shoe-plunger assembly on the swashplate 1 coincide with the Z-axis. In order to increase the power density of the hydraulic pump, reduce the outlet pressure pulsation, and improve the control characteristics, there is an additional angle β around the Z-axis on the swashplate plane. This additional angle will cause the upper and lower dead points of the sliding shoe-plunger assembly to change to the deflection axis 4, thereby changing the flow field characteristics of the aviation hydraulic pump.

[0021] like Figure 2 As shown, according to the coordinate transformation principle, the basic coordinate system when the swashplate angle is zero is O-xyz. When the swashplate plane rotates α around the y-axis, the coordinate system transforms to O-x1y1z1. When the swashplate rotates β around the z-axis, the coordinate system transforms to O-x2y2z2. This is the actual working state of the hydraulic pump. Therefore, according to the coordinate transformation relationship, the deflection angle γ of the upper and lower dead centers can be obtained as follows:

[0022]

[0023] like Figure 3 As shown, the deflection angle γ varies with different swashplate additional angles β and swashplate angles α. The larger the swashplate angle α, the smaller the deflection angle γ at the top and bottom dead centers; the larger the additional angle β, the larger the deflection angle γ at the top and bottom dead centers for the same swashplate angle. When the swashplate angle α is zero, the deflection angle γ at the top and bottom dead centers is 90°, meaning the piston pump draws oil from the inlet and discharges oil from the outlet, and the piston pump does not output oil.

[0024] like Figure 4 As shown, the deflection of the upper and lower dead centers alters the connection between the plunger chamber and the inlet and outlet oil windows of the distributor plate. Taking a right-hand rotary pump as an example, if the additional angle β is too large, at the upper dead center of the deflection shaft, when the plunger moves downward in the transition zone of the distributor plate, the plunger chamber still communicates with the low-pressure zone oil window, resulting in inlet oil discharge from the hydraulic pump. Similarly, at the lower dead center of the deflection shaft, when the plunger moves upward from the high-pressure zone to the low-pressure zone, the plunger chamber still communicates with the high-pressure zone, resulting in outlet oil suction from the plunger pump, which in turn reduces the volumetric efficiency of the plunger pump.

[0025] If the additional angle β is too small, at the top dead center of the deflection shaft, when the plunger moves upward in the transition zone of the distributor plate and the plunger cavity is disconnected from the low-pressure zone oil window and not connected to the discharge zone, a closed expansion phenomenon occurs in the plunger cavity. This phenomenon will lead to increased pulsation of the hydraulic pump outlet pressure. Similarly, at the bottom dead center of the deflection shaft, when the plunger moves downward from the transition zone of the distributor plate and the plunger cavity is still connected to the low-pressure zone, a closed compression phenomenon occurs in the plunger cavity. This phenomenon will cause the relevant components of the hydraulic pump to be subjected to a periodic impact force, making the rotor prone to overturning and causing the hydraulic pump to operate unstablely. At the same time, it will cause changes in the swashplate torque, leading to unstable variable control of the hydraulic pump, affecting the reliability and lifespan of the hydraulic pump.

[0026] like Figure 5 As shown, the length of the rotor's oblong orifice is l, R is the radius of the rotor oblong orifice distribution circle / oil window distribution circle of the oil distribution plate, and θ0 is the included angle of the rotor oblong orifice. Then:

[0027]

[0028] like Figure 6 As shown, in order to match the swashplate additional angle with the oil distribution plate structure, the following boundary conditions must be met:

[0029]

[0030] Then we have:

[0031]

[0032]

[0033] In the formula, θ1 is the angle between the unloading groove 6 of the oil window in the high-pressure zone and the z-axis; φ1 is the angle between the oil window in the low-pressure zone and the z-axis.

[0034] Once the basic dimensions of the plunger pump are determined, the dimensions of the rotor's oblong bore length l and the radius R of the rotor oblong bore distribution circle / oil window distribution circle of the distributor plate are also determined. Therefore, the design dimension of the angle θ1 between the starting position of the unloading groove 6 of the high-pressure zone oil window and the z-axis can be obtained. Since the pre-pressurization effect of the unloading groove varies under different swashplate angles, different speeds, and different pressure levels, the structural dimension of the angle φ2 between the high-pressure zone oil window and the z-axis needs to be designed according to the actual working conditions.

[0035] Similarly, the design dimensions of the transition zone from the high-pressure zone to the low-pressure zone of the oil distributor are as follows:

[0036]

[0037]

[0038] In the formula, φ4 is the angle between the oil window in the high-pressure zone at the bottom dead center and the z-axis.

[0039] Because the dead space volume of the plunger cavity is small when it transitions from the high-pressure zone to the low-pressure zone, its pre-pressure relief effect is much higher than its pre-pressure increase effect. Therefore, the unloading groove 6 in the transition zone from the high-pressure zone to the low-pressure zone is shorter than the unloading groove in the transition zone from the low-pressure zone to the high-pressure zone.

[0040] In actual design, since the distributor plate is simpler to machine than the swashplate, the design of the distributor plate's oil window is modified to match the swashplate's additional angle. Taking the matching design of the swashplate's additional angle and the distributor plate for a certain type of aviation hydraulic pump as an example, its main technical parameters are as follows:

[0041] Table 1 Main Technical Parameters of a Certain Type of Variable Variable Piston Pump

[0042]

[0043] Based on the above design method, the design dimensions of the oil distribution plate φ1 and φ4 of a certain type of aviation hydraulic pump can be calculated to be approximately 20°, and the design dimensions of θ1 and θ2 can be approximately 5°.

Claims

1. A design method for matching the swashplate additional angle of an aviation hydraulic pump with the distributor plate, characterized in that: By changing the size of the oil window on the oil distributor and the size of the unloading groove (6) on the oil window, the oil distributor is matched with the additional angle of the swashplate; Let α denote the swashplate angle, β denote the additional swashplate angle, l denote the length of the rotor's oblong hole in the aviation hydraulic pump, and R denote the radius of the rotor's oblong hole distribution circle. A basic coordinate system is established according to the right-hand rule. The plane that passes through the swashplate rotation axis (5) and is parallel to the swashplate plane is defined as the swashplate reference plane. The main shaft axis of the aviation hydraulic pump is taken as the x-axis, the main shaft extension end to the tail end of the aviation hydraulic pump is taken as the positive x-axis, and the swashplate rotation axis is taken as the y-axis. The Z-axis is determined. The angle between the unloading groove (6) of the oil window in the high-pressure zone and the z-axis is denoted as θ1, the angle between the unloading groove (6) of the oil window in the low-pressure zone and the z-axis is denoted as θ2, the angle between the oil window in the low-pressure zone and the z-axis is denoted as φ1, and the angle between the oil window in the high-pressure zone and the z-axis is denoted as φ4. The following conditions must be met simultaneously. ， 。

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