Swash plate assembly for improving control stability of variable displacement piston pump

Abstract

The utility model discloses a swash plate assembly for improving the control stability of a 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 surface is arranged on one 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 surface 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 utility model has the advantage that the large-range fluctuation of the outlet pressure of the variable pump can be avoided.

Description

Technical Field

[0001] The utility model belongs to the field of hydraulic equipment, and in particular relates to a swash plate assembly for improving the control stability of a variable plunger pump. Background Art

[0002] As a core component of hydraulic systems, axial variable displacement piston pumps are widely used in agricultural machinery, construction machinery, aerospace, and other fields due to their high operating pressure, high power density, low noise, high volumetric efficiency, and convenient variable displacement. The actuator's movement is primarily controlled by the output flow of the variable displacement piston pump, which in turn is achieved by the variable displacement mechanism driving the swash plate assembly.

[0003] Existing variable mechanisms, such as application number 201920362735.7, are a variable mechanism that can extend the service life of the main pump, including a swash plate assembly, which is rotatably connected to the pump casing. 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-hinged with the swash plate assembly. The variable piston pushes the swash plate assembly to rotate around the corresponding swing axis, changing the swing angle of the swash plate assembly, thereby changing the output flow of the variable plunger pump.

[0004] During actual use, it was found that when the variable piston pump is in a high-pressure, small-displacement operating condition, its output flow is unstable and the amplitude of change is large, which in turn causes low-frequency pulsation in the outlet pressure, causing the variable pump outlet pressure to fluctuate over a large range, which will affect the control accuracy of the main engine, especially when used on an aircraft, and may even lead to safety accidents. Utility Model Content

[0005] The purpose of the utility model is to provide a swash plate assembly for improving the control stability of a variable displacement piston pump. The utility model has the advantage of preventing the variable displacement pump outlet pressure from fluctuating widely.

[0006] The technical solution of the present utility model is: a swash plate assembly for improving the control stability of a variable piston pump, 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 perpendicularly through the axis of the variable piston, and the swash plate assembly contacts the variable piston through the arc surface.

[0007] In the aforementioned swash plate assembly for improving the control stability of a variable displacement piston pump, the wrap angle of the arc surface is 60-140°.

[0008] Compared with the prior art, the present invention provides a protrusion with an arc surface at the 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.

[0009] 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 working 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 working 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 direction of the friction 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.

[0010] The improved swash plate assembly of the present invention is designed to have the initial contact position between the swash plate assembly and the variable piston on the axis of the variable piston when the swash plate assembly's swing angle is zero. This ensures that the contact point with the variable piston is always near the axis of the variable piston during the variable adjustment process (if the center of the circle is not on the axis, the contact point will be offset to a greater extent). This reduces the radial component of the swash plate assembly's force on the variable piston, thereby reducing the friction between the variable piston and the variable cylinder, and reducing the impact of friction on control stability. This prevents large fluctuations in the outlet pressure, improves the control accuracy of the plunger pump, and enhances the reliability of the hydraulic system. When used on aircraft, it can effectively prevent safety accidents. In summary, the present invention has the advantage of preventing large fluctuations in the outlet pressure of the variable pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural diagram of Example 1.

[0012] Figure 2 It is a structural diagram of Example 2.

[0013] Figure 3 It is a schematic diagram of the dynamic characteristics of the variable piston pump of Example 2.

[0014] Figure 4 It is a schematic diagram of the dynamic characteristics of a variable piston pump using an existing swash plate assembly.

[0015] The markings in the accompanying drawings are: 1-drive shaft; 2-mounting seat; 3-front end bearing; 4-main shaft; 5-swash plate assembly, 51-protrusion, 52-arc surface; 6-slipper; 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

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0017] Example 1. A swash plate assembly for improving the control stability of a variable displacement piston pump, such as Figure 1 As shown, the outer edge of the swash plate assembly 5 is provided with a protrusion 51 facing the variable piston 13. The protrusion 51 is provided with an arc surface 52 on the side facing the variable piston 13. When the inclination angle of the swash plate assembly 5 is zero, that is, when the plane of the swash plate assembly 5 is perpendicular to the axis of the variable piston 13, the axis of the arc surface 52 passes perpendicularly 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 face of the variable piston 13. The wrap angle of the arc surface 52 is preferably 60-140°.

[0018] Example 2. A variable displacement piston pump, based on an existing variable displacement piston pump, utilizes the swash plate assembly 5 of Example 1. The remaining components remain unchanged, including the drive shaft 1, mounting base 2, front bearing 3, main shaft 4, slipper 6, chuck 7, plunger 8, rotor 9, housing 10, tail bearing 11, oil distributor cap 12, variable displacement piston 13, variable displacement cylinder 14, and other existing components. One end of the drive shaft 1 is connected to the main engine, and the other end is connected to the variable displacement piston pump main shaft 4. The main shaft 4 is supported by the front bearing 3 and tail bearing 11. When the main engine drives the drive shaft 1 to rotate, the drive shaft 1 drives the main shaft 4, which in turn drives the rotor 9, plunger 8, slipper 6, chuck 7, and other rotating components. Due to the angular deviation of the swash plate assembly 5, the plunger 8 performs linear reciprocating motion within the plunger hole of the rotor 9, thereby achieving the oil suction and discharge process of the plunger pump, and thus supplying oil to the hydraulic system.

[0019] Compared with the existing variable piston pump, the variable piston pump of Example 2 is tested for dynamic characteristics (switching from large flow to small flow). Figure 3 and Figure 4 It can be seen from the comparison that the outlet pressure of the variable piston pump of Example 2 is more stable, the fluctuation range is small, and the low-frequency fluctuation phenomenon basically disappears.

[0020] Example 3. Application of the variable displacement piston pump of Example 2 in an aircraft hydraulic control system.

Claims

1. A swash plate assembly for improving the control stability of a variable displacement piston pump, characterized by: 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. The swash plate assembly for improving the control stability of a variable displacement piston pump according to claim 1, characterized in that: The arc surface (52) has an angle of 60-140°.

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