Anti-overturning high-rotating-speed axial plunger pump

Abstract

The utility model discloses an anti-overturning high-rotating-speed axial plunger pump which comprises a swash plate, a cylinder body, a rotating shaft and a plurality of plungers, the other ends of the plungers are connected with sliding shoes, the sliding shoes are in sliding contact fit with the slope of the swash plate, the other ends of the plungers comprise ball heads, the sliding shoes comprise ball sockets, the ball centers of the ball heads of the plungers are all located on the same plane, and the ball sockets are located on the cylinder body. An inner spline is arranged at an inner hole of the cylinder body, an outer spline is arranged on the rotating shaft, the outer spline comprises a plurality of convex parts and concave parts, the concave parts comprise bottom walls, the top walls and the side walls of the convex parts and the bottom walls of the concave parts are all provided with convex arc-shaped contours and are all provided with the most salient points, and the most salient points are located at the center positions of the radial contours of the most salient points. The top wall and the side wall of the convex part and the most convex point of the bottom wall of the concave part are located at the position corresponding to the intersection point between the plane and the axis of the rotating shaft in the axial direction. According to the utility model, the overturning moment borne by the cylinder body can be reduced, so that the anti-overturning, high-rotating-speed and high-efficiency operation of the pump is realized.

Description

Technical Field

[0001] The utility model relates to an anti-overturning high-speed axial piston pump. Background Art

[0002] The swash plate axial piston pump is the heart of the hydraulic system and is a device that converts mechanical energy into hydraulic energy. It is widely used in engineering machinery, agricultural machinery, mining machinery, industrial equipment and other fields because of its high power-to-weight ratio, stepless flow adjustment, high continuous pressure, excellent oil absorption performance, high allowable speed, high reliability, long life, high efficiency and energy saving, good sealing, low noise level and low flow pulsation. Some machines are very compact in size, and the installation space reserved for the pump they carry is very narrow, which puts forward requirements for the plunger pumps they carry at higher speeds and smaller sizes.

[0003] The basic structure of a swash plate axial piston pump is mainly composed of a rotating shaft, a cylinder body, a plunger, a swash plate, a distribution plate, a casing, etc. The rotating shaft and the cylinder body are usually connected by a spline. When the rotating shaft drives the cylinder body to rotate, the plungers evenly distributed along the circumference of the cylinder body rotate with the cylinder body. At the same time, the plunger head is acted upon by the inclined surface of the swash plate to make reciprocating motion in the cylinder body hole. The rotating shaft is supported by bearings to keep the axis stable. The cylinder body distribution surface fits the distribution plate, and oil suction and discharge are achieved through the oil suction and oil pressure windows on the distribution plate. The inclination angle of the swash plate can be adjusted to change the plunger stroke and thus adjust the displacement of the pump. The splines of the rotating shaft and the cylinder body cooperate to transmit torque, so that the cylinder body rotates synchronously with the shaft, driving the plunger to complete the oil suction and discharge process.

[0004] In the prior art, the rotating shaft and the cylinder of the swash plate axial piston pump are generally connected by straight teeth or ordinary involute splines, such as Figures 1 to 3 As shown, during the operation of the pump, the rotating shaft will be subjected to the radial force F of the cylinder body. The rotating shaft will be bent and deformed by the radial force F, and an upward force Fr will be generated on the cylinder body. Under the action of the force Fr, the cylinder body will generate an overturning moment Tt, which will cause a slight tilting of the cylinder body and the distribution surface of the distribution plate, which will lead to an increase in the internal leakage of the pump and a decrease in the volumetric efficiency. In addition, the internal leakage under high-speed and high-pressure conditions increases nonlinearly with the increase in pressure. When the speed is increased to meet the high-speed and small-volume requirements in engineering machinery and other fields, the torque problem limits the upper limit of the speed, and it is impossible to take into account both high speed and high efficiency. Some existing technologies reduce internal leakage by increasing the bearing support stiffness or optimizing the sealing surface of the distribution plate, but there are shortcomings such as structural complexity leading to an increase in the volume of the pump body, increased costs, and the failure to fundamentally solve the overturning moment generation mechanism, and a significant decrease in the internal leakage control effect under extreme conditions. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an anti-overturning high-speed axial piston pump, which can reduce the overturning moment exerted on the cylinder body, so as to achieve the anti-overturning, high-speed and high-efficiency operation of the pump.

[0006] The utility model is an anti-overturning high-speed axial piston pump, comprising a swash plate, a cylindrical cylinder, a rotating shaft passing through the inner hole of the cylinder body, and a plurality of plungers, one end of the plurality of plungers is connected to the plurality of piston holes of the cylinder body, the other end of the plurality of plungers is connected to a sliding shoe, the sliding shoe is in sliding contact with the inclined surface of the swash plate, the other end of the plunger comprises a ball head, the sliding shoe comprises a ball socket movably connected with the ball head, the centers of the ball heads of the plurality of plungers are all located on the same plane, an inner spline is provided at the inner hole of the cylinder body, the inner spline adopts a conventional inner spline structure, an outer spline is provided on the rotating shaft to cooperate with the inner spline of the cylinder body to transmit torque, the outer spline comprises a plurality of axially spaced and evenly spaced along the axis of the rotating shaft. The present invention relates to a pair of cylindrical outer shells, wherein the cylindrical outer shells are connected to the cylindrical outer shell of the second cylindrical shell and the cylindrical outer shell of the first cylindrical shell. The cylindrical outer shell of the second cylindrical shell is connected to the cylindrical outer shell of the second cylindrical shell. The cylindrical outer shell of the second cylindrical shell is connected to the cylindrical outer shell of the second cylindrical shell.

[0007] Based on the solution of the present invention, when the rotating shaft is flexed and deformed, a radial outward force will be applied to the cylinder body. This force is applied to the cylinder body by the most convex point of the external spline of the rotating shaft (that is, the most convex point of the top wall, side wall of the convex part and the bottom wall of the concave part). Since there is a self-compensating space between the cylinder body and the rotating shaft, the cylinder body has a certain self-positioning ability, which can offset the overturning moment, reduce internal leakage, and improve the volumetric efficiency and speed limit of the pump.

[0008] Furthermore, the radial profiles of the top wall, side wall and bottom wall of the convex portion and the concave portion are all arc-shaped, the axial profiles of the top wall, side wall and bottom wall of the convex portion and the concave portion are all arc-shaped, the most convex point of the top wall, side wall and bottom wall of the convex portion and the concave portion is X1, the relative low point located at the center position of the radial profiles of the top wall, side wall and bottom wall of the convex portion but different from the axial position of X1 is X2, the axial distance between X1 and X2 is d, the radial height difference between X1 and X2 is h, and the radius of the arc-shaped profile of the top wall of the convex portion in the axial direction is R, It can reduce the generation of overturning moment, enhance the self-compensation ability, realize the anti-overturning and high-efficiency operation of the pump at high speed, and is more conducive to the CNC cutting of external splines. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the force analysis diagram of the rotating shaft of the axial piston pump;

[0010] Figure 2 This is the force analysis diagram of the cylinder of the axial piston pump;

[0011] Figure 3 Schematic diagram of the cylinder of an axial piston pump affected by the overturning moment;

[0012] Figure 4 A cross-sectional view of an embodiment of the present utility model;

[0013] Figure 5 This is a schematic diagram of the most convex point of the top wall of the convex portion of the external spline according to an embodiment of the present utility model;

[0014] Figure 6 A perspective view of a rotating shaft according to an embodiment of the present invention;

[0015] Figure 7 for Figure 6 Enlarged view of part A;

[0016] Figure 8 A side view of the rotating shaft of an embodiment of the present utility model;

[0017] Figure 9 This is a schematic diagram of the cooperation between the cylinder body and the rotating shaft in an embodiment of the utility model;

[0018] Figure 10 This is a schematic diagram of the forces acting on the top wall of the outer spline protrusion of the rotating shaft and the bottom inner wall of the inner spline recess of the cylinder body according to an embodiment of the utility model;

[0019] Figure 11 The comparison chart of internal leakage of pumps designed with external splines and conventional splines at a pump speed of n=2700rpm is shown.

[0020] Figure 12 This is a comparison chart of the volumetric efficiency of a pump designed with an external spline and a conventional spline for a rotating shaft at a pump speed of n=2700rpm. DETAILED DESCRIPTION

[0021] The embodiment of the utility model anti-overturning high speed axial piston pump is as follows: Figures 4 to 12As shown, it includes a swash plate 1, a cylindrical cylinder body 2, a rotating shaft 3 passing through the inner hole of the cylinder body 2, and multiple plungers 4. One end of the multiple plungers 4 is connected to the multiple piston holes of the cylinder body 2, and the other end of the multiple plungers 4 is connected to a sliding shoe 5. The sliding shoe 5 is in sliding contact with the inclined surface 11 of the swash plate 1. The other end of the plunger 4 includes a ball head 41. The sliding shoe 5 includes a ball socket movably connected to the ball head 41. The centers of the ball heads 41 of the multiple plungers 4 are all located on the same plane a parallel to the inclined surface of the swash plate 1. Both ends of the rotating shaft 3 are supported by bearings 6. The rotating shaft 3 is used to be connected to the motor and can be driven to rotate by the motor. The cylinder body 2 is sleeved on the rotating shaft 3. The two are connected to each other through the external spline 31 on the rotating shaft 3 and the internal spline 21 on the inner side of the cylinder body 2 to form a transmission connection. In addition, it also includes a distribution plate 7 and a rear cover 8 that cooperate with the cylinder body 2.

[0022] Working principle: The rotating shaft 3 is driven by the motor to rotate the cylinder body 2 and multiple plungers 4. The plunger 4 reciprocates axially along the inclined surface 11 of the swash plate 1 in the piston hole, causing the volume of the piston hole to change. The waist-shaped channel on the distribution surface of the cylinder body 2 fits with the suction and pressure oil window of the distribution plate 7. The oil flows through the oil suction channel and oil outlet channel of the rear cover 8 and the crescent groove of the distribution plate 7 to achieve oil suction and discharge.

[0023] like Figure 9 As shown, an internal spline 21 is provided at the inner hole of the cylinder body 2. The internal spline 21 adopts a conventional structure, including a plurality of convex portions 211 and concave portions 212 distributed at intervals in the circumferential direction. The convex portion 211 includes a top wall and two side walls arranged on both sides of the top wall in the circumferential direction. The concave portion 212 includes a bottom wall connected to the side walls. The radial profiles of the top wall, side wall of the convex portion and the bottom wall of the concave portion of the internal spline 21 are all concave arc shapes, and the axial profile is straight.

[0024] The rotating shaft 3 is provided with an external spline 31 which is connected with the internal spline 21 of the inner hole of the cylinder body 2 to transmit torque. Figures 6 and 7As shown, the external spline 31 includes a plurality of convex portions 311 uniformly spaced along the circumferential axis b of the rotating shaft 3, and a plurality of concave portions 312 spaced between adjacent circumferential convex portions 311. The convex portion 311 includes a top wall 3111 radially outward relative to the axial center b of the rotating shaft 3 and two side walls in corresponding circumferential directions. The concave portion 312 includes a bottom wall connected to the side walls. The top wall, side walls of the convex portion 311 and the bottom wall of the concave portion 312 all have convex arcs. The top wall, side wall and bottom wall of the convex portion 311 and the concave portion 312 each have a most convex point. The most convex point of the top wall, side wall and bottom wall of the convex portion 311 and the concave portion 312 is located at the center of its radial profile. The most convex point of the top wall, side wall and bottom wall of the convex portion 311 and the concave portion 312 is located in the axial direction at a position corresponding to the intersection of the plane a and the axis b of the rotation axis 3, that is, the most convex point and the intersection are in the same axial position. Figure 5 shown.

[0025] Based on the solution of the present utility model, the rotating shaft 3 of the pump will be subjected to the radial force F of the cylinder body 2 during operation. The rotating shaft 3 will be flexurally deformed by the radial force F. When the rotating shaft 3 is flexurally deformed, a radially outward force will be applied to the cylinder body 2. The force is applied to the cylinder body 2 by the most convex point of the external spline of the rotating shaft 3 (i.e., the most convex point of the top wall, side wall of the convex portion 311 and the bottom wall of the concave portion 312). Since there is a self-compensating space between the cylinder body 2 and the convex portion 311 of the rotating shaft 3, the cylinder body 2 has a certain self-positioning ability, which can offset the overturning moment, reduce internal leakage, and improve the volumetric efficiency and speed limit of the pump.

[0026] The radial profiles of the top wall 3111 and the side walls of the convex portion 311 and the bottom wall of the concave portion 312 are all arc-shaped, and the axial profiles of the top wall 3111 and the side walls of the convex portion 311 and the bottom wall of the concave portion 312 are all arc-shaped.

[0027] Taking the top wall 3111 of the convex portion 311 as an example, assuming that its most convex point is X1, its force matching with the spline 21 in the cylinder body 2 in the microscopic state can be referred to Figure 10 When the rotating shaft 3 rotates, the cylinder body 2 applies a radial force F thereto. The radial force F acts on the most convex point X1 of the top wall 3111 of the convex portion 311 of the external spline 31 of the rotating shaft 3 .

[0028] The radial profiles of the top wall, side wall and bottom wall of the convex portion and the concave portion are all arc-shaped. The axial profiles of the top wall 3111 and side wall of the convex portion 311 and the bottom wall of the concave portion 312 are all arc-shaped. The most convex point of the top wall 3111 and side wall of the convex portion 311 and the bottom wall of the concave portion 312 is X1. The relatively low point located at the center position of the radial profiles of the top wall 3111 and side wall of the convex portion 311 and the bottom wall of the concave portion 312 but different from the axial position of X1 is X2. The axial distance between X1 and X2 is d. The radial height difference between X1 and X2 is h. The radius of the arc-shaped profile of the top wall 3111 of the convex portion 311 in the axial direction is R. , which facilitates the precise design and processing of splines, ensures uniform force, improves the smoothness of torque transmission, reduces wear caused by stress concentration, extends the service life of the pump, further improves self-positioning accuracy and anti-overturning ability, and facilitates CNC cutting of the top wall profile.

[0029] Figure 8 The relationship between the axial distance and the radial height difference between two relatively low points X2 located on both sides of the highest point X1 of the top wall 3111 is illustrated.

[0030] like Figures 11 to 12 As shown, a comparative test was conducted on the performance of a pump with an external spline structure for the rotating shaft employed in an embodiment of the present invention and a conventional spline structure at a pump speed of 2700 rpm. The test data showed that the pump with the external spline structure for the rotating shaft employed in the present invention had significantly lower internal leakage than a pump with a conventional spline structure, while also significantly improving its volumetric efficiency. This test result fully demonstrates that the present invention can effectively reduce internal leakage and improve volumetric efficiency, thereby achieving anti-overturning, high-speed, and high-efficiency operation of the pump.

[0031] The above embodiment is only one preferred embodiment of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are all included in the protection scope of the present invention.

Claims

1. The axial piston pump of claim 1, wherein the piston rod has a cam portion and a piston rod portion, the piston rod having a cam portion and a piston rod portion being affixed to the piston rod and the piston rod portion being affixed to the piston rod portion. The top wall, side wall and bottom wall of the convex portion all have a convex arc-shaped profile, and the top wall, side wall and bottom wall of the convex portion all have a most convex point. The most convex points of the top wall, side wall and bottom wall of the convex portion are located at the center position of their radial profiles, and the most convex points of the top wall, side wall and bottom wall of the convex portion are axially located at a position corresponding to the intersection between the plane and the axis of rotation.

2. The anti-overturning high-speed axial piston pump according to claim 1, characterized in that: The radial profiles of the top wall and the side wall of the convex portion and the bottom wall of the concave portion are all arc-shaped.

3. The anti-overturning high-speed axial piston pump according to claim 1 or 2, characterized in that: The axial profiles of the top wall, side wall, and bottom wall of the convex portion are all arc-shaped. The most convex point of the top wall, side wall, and bottom wall of the convex portion is X1. The relatively low point located at the center of the radial profiles of the top wall, side wall, and bottom wall of the convex portion but at a different axial position from X1 is X2. The axial distance between X1 and X2 is d. The radial height difference between X1 and X2 is h. The radius of the arc-shaped profile of the top wall of the convex portion in the axial direction is R. .

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