Swash plate assembly, variable displacement piston pump and application of variable displacement piston pump

Abstract

The invention discloses a swash plate assembly, a variable displacement piston pump and application of the variable displacement piston pump. A protruding part facing a variable displacement piston is arranged on one side of the outer edge of the swash plate assembly, an arc face is arranged on the side, facing the variable displacement piston, of the protruding part, and when the inclination angle of a swash plate is zero, the axis of the arc face perpendicularly penetrates through the axis of the variable displacement piston; the swash plate assembly makes contact with the variable piston through an arc face. The method has the advantage that the large-range fluctuation of the outlet pressure of the variable pump can be avoided.

Description

Technical Field

[0001] The invention belongs to the field of hydraulic equipment, and in particular relates to a swash plate assembly, a variable piston pump and a use of the variable piston pump. Background Art

[0002] As one of the core components of the hydraulic system, the axial variable piston pump has the characteristics of high working pressure, high power density, low noise, high volumetric efficiency, convenient variable, etc., and is widely used in agricultural machinery, engineering machinery, aerospace and other fields. Among them, the action change of the actuator is mainly controlled by the output flow of the variable piston pump, and the output flow change of the variable piston pump is mainly achieved by the variable mechanism driving the swash plate assembly to rotate.

[0003] Existing variable mechanisms, such as a variable mechanism with application number 201920362735.7 that can extend the service life of the main pump, include a swash plate assembly, which is rotatably connected to the pump housing, and one side of the outer edge of the swash plate assembly is a variable piston that performs reciprocating linear motion in the variable cylinder. The variable piston is arranged in the variable cylinder, and the variable piston is ball-jointed to the swash plate assembly. The variable piston pushes the swash plate assembly to rotate around the corresponding swing axis, thereby changing the swing angle of the swash plate assembly and changing the output flow of the variable plunger pump.

[0004] In actual use, it was found that when the variable piston pump is in a high-pressure and small-displacement condition, its output flow is unstable and the variation amplitude is large, which leads to low-frequency pulsation of the outlet pressure and a large range of fluctuations in the outlet pressure of the variable pump. This will affect the control accuracy of the main engine, especially when used on an aircraft, and may even cause safety accidents. Summary of the invention

[0005] The purpose of the present invention is to provide a swash plate assembly, a variable displacement piston pump and a use of the variable displacement piston pump. The present invention has the advantage of being able to avoid large-scale fluctuations in the outlet pressure of the variable displacement pump.

[0006] The technical solution of the present invention is: a swash plate assembly, wherein one side of the outer edge of the swash plate assembly is provided with a protrusion facing the variable piston, and the side of the protrusion facing the variable piston is provided with an arc surface. When the inclination angle of the swash plate assembly is zero, the axis of the arc surface passes vertically through the axis of the variable piston, and the swash plate assembly contacts the variable piston through the arc surface.

[0007] A variable displacement piston pump comprises the aforementioned swash plate assembly.

[0008] The aforementioned variable piston pump is used in aircraft hydraulic control systems.

[0009] Compared with the prior art, the present invention provides a protrusion with an arc surface at a location corresponding to the variable piston on the basis of the existing swash plate assembly, and the axis of the arc surface is perpendicular to the axis of the variable piston.

[0010] After a long period of observation, experimentation and analysis, the applicant found that the reason why the outlet pressure of the existing variable piston pump fluctuates widely when it is in a high-pressure and small-displacement condition is that, on the one hand, the initial contact position between the swash plate assembly and the variable piston is not on the axis of the variable piston, resulting in a lateral component of the variable piston. When the pump is in a high-pressure and small-displacement condition, the swash plate swing angle is small and the variable piston extends. Due to the matching clearance between the variable piston and the variable cylinder, the variable piston is deflected. The friction between the variable piston and the variable cylinder at the bottom and the orifice is relatively large. In addition, the swash plate assembly is in a continuous swinging state. The superposition of the switching of the friction direction between the variable piston and the variable cylinder makes the entire variable mechanism unstable, resulting in an increase in the amplitude of the pump output flow change, which in turn causes a large range of low-frequency fluctuations in the outlet pressure.

[0011] The improved swash plate assembly of the present invention is designed such that when the swash plate assembly swings at a zero angle, the initial contact position between the swash plate assembly and the variable piston is on the axis of the variable piston, so as to ensure that during the variable process, the contact point with the variable piston is always near the axis of the variable piston (if the center of the circle is not on the axis, the contact point will be offset in a large range), thereby reducing the radial component of the swash plate assembly on the variable piston, thereby reducing the friction between the variable piston and the variable cylinder, and reducing the influence of the friction on the control stability, thereby avoiding large-scale fluctuations in the outlet pressure, improving the control accuracy of the plunger pump, and improving the reliability of the hydraulic system. When used on an aircraft, it can effectively avoid safety accidents. In summary, the present invention has the advantage of avoiding large-scale fluctuations in the outlet pressure of the variable pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of Example 1.

[0013] Figure 2 It is a structural schematic diagram of Example 2.

[0014] Figure 3 It is a schematic diagram of the dynamic characteristics of the variable piston pump of Example 2.

[0015] Figure 4 It is a schematic diagram of the dynamic characteristics of a variable piston pump using an existing swash plate assembly.

[0016] The markings in the attached drawings are: 1-transmission shaft; 2-mounting seat; 3-front end bearing; 4-main shaft; 5-swash plate assembly, 51-protrusion, 52-arc surface; 6-shoe; 7-chuck; 8-variable plunger; 9-rotor; 10-housing; 11-tail end bearing; 12-oil distributor cover; 13-variable piston; 14-variable cylinder. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0018] Example 1. Figure 1 As shown, a protrusion 51 facing the variable piston 13 is provided on one side of the outer edge of the swash plate assembly 5, and an arc surface 52 is provided on the side of the protrusion 51 facing the variable piston 13. When the inclination angle of the swash plate assembly 5 is zero, that is, when the plane where the swash plate assembly 5 is located is perpendicular to the axis of the variable piston 13, the axis of the arc surface 52 vertically passes through the axis of the variable piston 13, and the swash plate assembly 5 contacts the variable piston 13 through the arc surface 52. The center of the arc surface 52 is on the axis of the variable piston 13. Within the swing range of the swash plate assembly 5, the arc surface 52 always contacts the end surface of the variable piston 13.

[0019] Embodiment 2. A variable displacement piston pump, based on the existing variable displacement piston pump, adopts the swash plate assembly 5 in embodiment 1, and the other components remain unchanged, including the transmission shaft 1, mounting seat 2, front bearing 3, main shaft 4, slipper 6, chuck 7, plunger 8, rotor 9, housing 10, tail bearing 11, oil distributor 12, variable piston 13, variable cylinder 14 and other existing components. One end of the transmission shaft 1 is connected to the main engine, and the other end is connected to the main shaft 4 of the variable displacement piston pump. The main shaft 4 is supported by the front bearing 3 and the tail bearing 11. When the main engine drives the transmission shaft 1 to rotate, the transmission shaft 1 drives the main shaft 4 to rotate, and the main shaft 4 drives the rotor 9, plunger 8, slipper 6, chuck 7 and other rotating parts to rotate. Due to the deflection angle of the swash plate assembly 5, the plunger 8 performs linear reciprocating motion in the plunger hole of the rotor 9, thereby realizing the oil suction and discharge process of the plunger pump, and then supplying oil to the hydraulic system.

[0020] Compared with the existing variable piston pump, the variable piston pump of Example 2 is more stable when conducting a dynamic characteristic test (switching from a large flow rate to a small flow rate). Figure 3 and Figure 4 It can be seen from the comparison that the outlet pressure of the variable piston pump in Example 2 is more stable, the fluctuation range is small, and the low-frequency fluctuation phenomenon basically disappears.

[0021] Embodiment 3. Application of the variable displacement piston pump of Embodiment 2 in an aircraft hydraulic control system.

Claims

1. A swash plate assembly, characterized in that: A protrusion (51) facing the variable piston (13) is provided on one side of the outer edge of the swash plate assembly (5); an arc surface (52) is provided on the side of the protrusion (51) facing the variable piston (13); when the inclination angle of the swash plate assembly (5) is zero, the axis of the arc surface (52) vertically passes through the axis of the variable piston (13), and the swash plate assembly (5) contacts the variable piston (13) through the arc surface (52).

2. Variable displacement piston pump, characterized in that: The invention comprises the swash plate assembly as claimed in claim 1.

3. Application of the variable displacement piston pump according to claim 2 in an aircraft hydraulic control system.

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