Plunger for hydraulic device and hydraulic device

Abstract

The present invention discloses a plunger for a hydraulic device and a hydraulic device. The invention solves the problem that the gap and leakage between the sliding shoe of the plunger for the hydraulic device and the swash plate cannot be correctly set in the hydraulic device, and the pressure regulating effect on the sliding surface of the swash plate and the sliding shoe cannot be fully exerted. In a hydraulic device in which a plurality of plungers 111 for the hydraulic device reciprocate with respect to the swash plate 103 and play the role of an oil pump, the end of the plunger 111 for the hydraulic device is provided with a swash plate 103 and a sliding sliding shoe 113, and a lightweight material 117 forming an oil guide groove 118 is fixed on the outer periphery in a plunger cavity 116 formed on the shaft, and lubricating oil is supplied between the sliding surface 115 at the end of the sliding shoe 113 and the swash plate 103 through an oil guide hole 125 formed between the oil guide groove 118 and the inner peripheral surface of the plunger cavity 117.

Description

Technical Field

[0001] The present invention relates to a plunger for a hydraulic device and a hydraulic device. Background Art

[0002] Hydraulic devices such as hydraulic pumps and hydraulic motors have the following characteristics: using Pascal's law, they can use relatively small equipment to exert huge power, making it easy to control the output and speed, and can also be remotely controlled. Hydraulic devices are widely used in factories as power for presses or pressurizing devices, freight elevators, or various small machines. In addition, as construction machinery or loading and unloading machinery, they are also used to operate the working mechanical parts of electric shovels or trailers, brakes of automobiles, control surfaces of aircraft, or sluice gates.

[0003] In order to operate the hydraulic device, the pressure of the hydraulic oil discharged from the hydraulic pump must be reduced to a specified level through the pressure control valve, and the flow rate must be controlled by the flow control valve and sent to the hydraulic motor or hydraulic cylinder to rotate the hydraulic motor or operate the hydraulic cylinder. In addition, the direction of rotation (forward or reverse) and the extension and retraction of the hydraulic cylinder are controlled by the direction control valve.

[0004] A hydraulic pump is a hydraulic device that applies pressure to hydraulic oil and delivers it to a hydraulic circuit. It uses an electric motor or engine as a power source and discharges the hydraulic oil to the hydraulic circuit through rotation. Hydraulic pumps are classified into different types, such as vane pumps, gear pumps, screw pumps, and plunger pumps, depending on their structure.

[0005] The plunger pump, also known as the "piston pump", is a hydraulic pump that generates hydraulic power by the reciprocating motion of a plunger arranged around the crankshaft. It is roughly divided into "axial piston pump" (the direction of movement of the plunger is parallel to the axis) and "radial piston pump" (the direction of movement is from the axis to the outside) according to the different directions of movement of the piston on the axis.

[0006] Axial piston pumps include "swash plate type" and "swash axis type" hydraulic pumps, and are divided into "fixed displacement type" hydraulic pumps and "variable displacement type" hydraulic pumps according to displacement. In addition, the swash plate type axial piston pump is a "fixed swash plate type" hydraulic pump in which the cylinder body connected to the drive shaft rotates, causing multiple plungers to reciprocate due to the fixed swash plate, and the swash plate connected to the drive shaft rotates, causing multiple plungers to reciprocate.

[0007] Fig.13 It is a schematic diagram of the swash plate type hydraulic pump 1. Fig.13 In the figure, 1-swash plate type piston pump, 3-swash plate, 4-port plate, 5-oil port, 6-drive shaft, 8-cylinder body, 9-cylinder hole, 11-plunger. If the cylinder body 8 connected with the drive shaft 6 is rotated relative to the fixed swash plate 3, the multiple slidable plungers 11 provided in the multiple cylinder holes 9 of the cylinder body 8 can perform axial reciprocating motion through the inclination of the swash plate 3.

[0008] The plunger 11 is pulled out of the cylinder 8 along the surface of the swash plate, and the hydraulic oil flows into the plunger 11 from the suction side oil port 5 of the distribution plate 4. The plunger 11 is pressed into the cylinder 8 along the surface of the swash plate 3, and the hydraulic oil in the plunger 11 is discharged from the discharge oil measuring port 5 of the distribution plate 4, thereby playing the role of an oil pump.

[0009] Fig.14 Indicates, for example: Patent document 1 Figure 1 A side cross-sectional view of a conventional swash plate type axial piston pump is shown. Fig.14 Among them, 201-slant plate type axial piston pump, 202a-pump housing, 202b-end cover, 203-slant plate, 204-distribution plate, 205-oil port, 206-drive shaft, 206a-spline, 207a-bearing, 207b-bearing, 208-cylinder body, 209-cylinder hole, 210-slipper type plunger, 211-plunger, 212-concave spherical surface, 213-slipper, 214-convex spherical surface, 215-sliding surface.

[0010] Fig.14 In the swash plate type hydraulic pump, a cylindrical pump housing 202a with one axial end closed is provided with an end cover 202b at the other end. A swash plate 203 is provided at one end of the pump housing 202a, and a drive shaft 206 passes through the swash plate 203 on the axis of the pump housing 202a and the end cover 202b, and can rotate freely through the support of bearings 207a and 207b.

[0011] The cylinder body 208 is mounted on the drive shaft 206 via a spline 206a, and a plurality of cylinder holes 209 are axially arranged on the circumference of the cylinder body 208, in which a freely sliding plunger 211 is embedded. By providing a concave spherical surface 212 at the end of the plunger 211, a convex spherical surface 214 at one end of a sliding shoe 213 is fitted on the concave spherical surface 212, and the end of the concave spherical surface 212 is reduced in diameter, so that the sliding shoe type plunger 210 can be formed so as to be freely swingably combined.

[0012] The sliding surface 215 provided at the other end of the sliding shoe 213 is slidably butted against the swash plate 203. The valve plate 204 is disposed on the opposite surface of the pump housing 202a to the swash plate 203, and the valve plate 204 is slidably butted against the cylinder block 208. The valve plate 204 is provided with an oil port 205 for supplying or discharging pressurized oil to or from the cylinder hole 209. The oil port 205 is connected to a pressurized oil supply and discharge passage (not illustrated) provided in the pump housing 202a.

[0013] Figures 15 to 19 It represents the plunger structure used in the conventional swash plate type hydraulic device. Fig.15 For example, FIG. 1 and FIG. 2 of Patent Document 2 are cross-sectional views of a plunger for a hollow hydraulic device, which is also described. Fig.15In the figure, 211- plunger, 212- concave spherical surface, 213- sliding shoe, 214- convex spherical surface, 215- sliding surface, 216- plunger cavity, the convex spherical surface 214 at the end of the plunger 211 is combined with the concave spherical surface of the sliding shoe 213 to swing freely, and the sliding surface 215 of the sliding shoe 213 slides on the inclined plate (not illustrated).

[0014] Fig.15 The hollow type plunger for hydraulic device shown refers to a plunger for hydraulic device of a commonly used structure, which has a low manufacturing cost. However, there are disadvantages that the plunger cavity 216 provided on the plunger 211 forms a dead volume, the compression amount increases, the efficiency decreases accordingly, the flow pulsation becomes larger, and a jet is formed when the low-pressure side is opened, which is easy to cause cavitation, unstable movement, and increased noise.

[0015] Figure 16 to Figure 19 The purpose of each plunger structure described is to reduce the above-mentioned dead volume. Fig.16 The solid type hydraulic plunger shown is a plunger in which an oil guide hole 218 is formed on the central axis of a solid portion 217 of a plunger 211 . Fig.16 The plunger 211 shown can reduce the dead volume, but on the other hand, it becomes heavier, the squeezing force on the cylinder wall increases, it is not suitable for high-speed operation, and there is a disadvantage that the processing time for long holes increases.

[0016] Fig.17 The illustrated filling type hydraulic device uses a plunger 211 , in which a soluble resin 219 is filled into a plunger cavity of the plunger 211 to form a solid, and an oil guide hole 218 is formed on the central axis of the soluble resin 211 . Fig.17 In the machine plunger 211, the dead volume is reduced and the weight is reduced, but a special process of filling with resin is required, and there is also a disadvantage that a thread groove needs to be provided at the inner diameter end of the plunger to prevent it from falling off.

[0017] Fig.18 The plunger 211 for a welded hydraulic device has a plunger cavity penetrating through the plunger 211 and an oil guide hole 218 formed on the central axis, and the end portion is welded 220 by friction pressure. Fig.19 In the following, the plunger 211 for the welded hydraulic device is described in more detail.

[0018] Fig.19 In the plunger 211 for the welded hydraulic device, a damping hole 221 is formed on the convex spherical surface 214 at the end of the plunger 211, and an oil guide hole 218 is formed on the central axis of the plunger 211. At the same time, a plunger cavity is formed on the plunger 211 by a perforation process 223 of "deep digging" or "drilling through" a deep hole, and a welding portion 220 is formed at the end through an anti-deformation plate 222.

[0019] Fig.19The welded plunger has the advantage of being lightweight, but since the slender oil guide holes and damping holes are processed on hard materials, there are disadvantages such as the need to repeatedly insert and pull the tool, especially the perforation process 223, which causes severe blade wear and short tool life, and the need for special machinery and proprietary technology of friction welding machines for peripheral finishing.

[0020] In addition, since the adjustment portion is short, it is difficult to design the hydraulic balance of the sliding surface 215 of the slipper 213 to the swash plate 203. In addition, in order to prevent the slipper 213 from floating on the swash plate 203, the slipper needs to be pressed against the swash plate, which makes the slipper 213 and the swash plate 203 contact and easily cause bite wear.

[0021] Non-Patent Document 1 provides a theoretical analysis of the hydraulic balance of the shoe with respect to the swash plate. Fig. 20 In the figure, the plunger for the hydraulic device described in Table 3-4 on page 148 of Non-Patent Document 1 is explained. Fig. 20 In the equation, a is the diameter of the damping hole, l is the length of the damping hole, d is the diameter of the plunger end, R1 and R2 are the inner and outer diameters of the sliding surface of the shoe, and the oil pressure of the hydraulic oil pressing the plunger is Pp and the oil pressure of the sliding surface is Pb. Then, the oil pressure of the sliding surface (concave surface pressure) Pb and the clearance h between the sliding surface of the shoe and the swash plate can be calculated using the following formulas (1) and (2).

[0022]

[0023]

[0024] In addition, referring to Non-Patent Document 1, for example, as shown in Table 1, when the equivalent area Ab of the shoe is larger than the equivalent area Ap of the plunger end, the balance ratio η of the squeeze force Fp and the breakaway force Fb is 1, and the clearance h between the sliding surface of the shoe and the swash plate and the leakage amount Q can be set and calculated. It can be seen that the effect of the adjustment process is very important, and the oil pressure (concave surface pressure) Pb on the sliding surface can be controlled.

[0025]

[0026] As mentioned above, when the equivalent area Ab of the sliding shoe is larger than the equivalent area Ap of the plunger end, the clearance h (oil film thickness) can be determined in the design, and the performance is stable. However, there is still a problem of difficulty in dimensional realization when designing the adjustment part of the plunger for hydraulic devices. As shown in the clearance h formula (2) of non-patent document 1, (a 4 / 1) is important. If the orifice length l is reduced, the orifice diameter a 4 The value will also become smaller; if the damping length 1 increases, the damping hole diameter a 4The value also needs to be increased, but in order to obtain the correct gap h value, it is not easy to correctly design and manufacture the diameter a and length 1 of the damping hole.

[0027] [Prior art literature]

[0028] [Patent Document]

[0029] [Patent Document 1] Japanese Patent Application Publication No. 2000-329054

[0030] [Patent Document 2] Japanese Patent Publication No. 2004-534171

[0031] [Non-patent literature]

[0032] [Non-patent document 1] Practical Hydraulics Pocket Handbook (2012 edition), page 148, Table 3-5, published by the Japan Fluid Power Industry Association Summary of the invention

[0033] The problem to be solved by the present invention is that the conventional hydraulic device cannot properly set the gap and leakage between the sliding shoe of the hydraulic device plunger and the swash plate, and therefore cannot fully exert the effect of controlling the pressure on the sliding surface of the swash plate and the sliding shoe.

[0034] The plunger for hydraulic device of the present invention is a plunger that performs an oil pump function by axially reciprocating relative to a swash plate in a hydraulic device using a plurality of plungers for hydraulic device. The plunger is characterized in that the end portion is provided with the swash plate and a shoe that slides on the swash plate surface, a lightweight material is embedded in the plunger cavity formed by the shaft portion of the plunger for hydraulic device, the outer periphery of the lightweight material has an oil guide groove, and lubricating oil is supplied between the sliding surface of the end portion of the shoe and the swash plate through an oil guide hole formed between the oil guide groove and the inner peripheral surface of the plunger cavity. In addition, the plunger for hydraulic device of the present invention is characterized in that the oil guide groove is a machined groove formed on the cylindrical outer peripheral surface of the lightweight material, and the oil guide hole supplies lubricating oil between the sliding surface of the end portion of the shoe and the swash plate according to the set oil film thickness and the control oil pressure, forming a predetermined flow path length and a predetermined flow path cross-sectional area.

[0035] In addition, the hydraulic device of the present invention is characterized in that, in a hydraulic device in which a plurality of hydraulic plungers reciprocate a swash plate to function as an oil pump, the end of the hydraulic plunger is provided with the swash plate and a shoe sliding on the swash plate surface, a lightweight material is embedded in a plunger cavity formed by the shaft of the hydraulic plunger, the lightweight material has an oil guide groove on the outer periphery, and lubricating oil is supplied between the sliding surface of the shoe end and the swash plate through an oil guide hole formed between the oil guide groove and the inner periphery of the plunger cavity. In addition, the hydraulic device of the present invention is characterized in that the oil guide groove is a machined groove formed on the cylindrical outer periphery of the lightweight material, and the oil guide hole supplies lubricating oil between the sliding surface of the shoe end and the swash plate according to the set oil film thickness and the control oil pressure, forming a predetermined flow path length and a predetermined flow path cross-sectional area.

[0036] The plunger for hydraulic device and the hydraulic device of the present invention can form the oil guide groove into a shape with a small cross-sectional area and a long length, so that the gap and leakage between the sliding shoe of the plunger for hydraulic device and the swash plate can be accurately set, and the pressure regulation effect on the sliding surface of the swash plate and the sliding shoe can be fully exerted, so that the plunger for hydraulic device and the hydraulic device can operate stably and at high speed. In addition, the plunger for hydraulic device and the hydraulic device of the present invention do not need to use new production equipment or complicated production processes, and can quickly and easily form a processing groove with excellent precision using existing equipment such as lathes for metal processing and resin molding.

[0037] The present invention provides a plunger for a hydraulic device, which is a plunger for a hydraulic device used in a hydraulic device in which a plurality of plungers for a hydraulic device perform axial reciprocating motion on a swash plate to play the role of an oil pump. The end portion has the swash plate and a sliding shoe. A lightweight material forming an oil guide groove is fixed to the outer periphery in a plunger cavity formed by the shaft portion of the plunger for the hydraulic device. Lubricating oil is supplied between the sliding surface of the end portion of the sliding shoe and the swash plate through an oil guide hole formed between the oil guide groove and the inner peripheral surface of the plunger cavity.

[0038] Optionally, the oil guide groove is a machined groove formed on the cylindrical outer peripheral surface of the lightweight material, and the oil guide hole supplies lubricating oil to the sliding surface of the end of the shoe and the swash plate according to a preset oil film thickness and controlled oil pressure, thereby forming a specified flow path length and a specified flow path cross-sectional area.

[0039] The present invention also provides a hydraulic device, which is a hydraulic device in which multiple hydraulic device plungers cause a swash plate to reciprocate and function as an oil pump. The hydraulic device plunger has the swash plate and a sliding shoe at its end. A lightweight material forming an oil guide groove is fixed on the outer periphery in a plunger cavity formed by a shaft. Lubricating oil is supplied between the sliding surface at the end of the shoe and the swash plate through an oil guide hole formed between the oil guide groove and the inner peripheral surface of the plunger cavity.

[0040] Optionally, the oil guide groove is a machined groove formed on the cylindrical outer circumferential surface of the lightweight material, and the oil guide hole supplies lubricating oil between the sliding surface of the shoe end and the swash plate according to a preset oil film thickness and controlled oil pressure, thereby forming a specified flow path length and a specified flow path cross-sectional area.

[0041] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0043] Figure 1 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 1);

[0044] Figure 2 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 2);

[0045] Figure 3 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 3);

[0046] Figure 4 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 4);

[0047] Figure 5 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 5);

[0048] Figure 6 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 6);

[0049] Figure 7 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 7);

[0050] Figure 8 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 8);

[0051] Fig. 9 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 9);

[0052] Fig.10 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 10);

[0053] Fig.11 It is an explanatory diagram showing application example 1 of the hydraulic device of the present invention (Example 11);

[0054] Fig.12 It is an explanatory diagram showing application example 2 of the hydraulic device of the present invention (Example 12);

[0055] Fig.13 This is an explanatory diagram showing the principle of the hydraulic device;

[0056] Fig.14 It is an explanatory diagram showing a conventional example of a hydraulic device;

[0057] Fig.15 It is an explanatory diagram showing a prior art example 1 of a plunger for a hydraulic device;

[0058] Fig.16 It is an explanatory diagram showing a prior art example 2 of a plunger for a hydraulic device;

[0059] Fig.17 It is an explanatory diagram showing a prior art example 3 of a plunger for a hydraulic device;

[0060] Fig.18 It is an explanatory diagram showing a prior art example 4 of a plunger for a hydraulic device;

[0061] Fig.19 A detailed description diagram showing a prior art example 4 of a plunger for a hydraulic device;

[0062] Fig. 20 This figure is an illustration of the calculation formula for the oil pressure balance of the hydraulic device.

[0063] Explanation of symbols

[0064] 1. Swash plate type piston pump; 3. Swash plate; 4. Port plate; 5. Oil port; 6. Drive shaft; 8. Cylinder block; 9. Cylinder bore; 11. Plunger; 101. Swash plate type axial piston pump; 102. Pump housing; 102a. Pump housing; 102b. End cover; 103. Swash plate; 104. Port plate; 105. Oil port; 106. Drive shaft; 106a. Spline; 107. Bearing; 107a. Bearing; 107b. Bearing; 108. Cylinder block; 109. Cylinder bore; 110. Slipper type plunger; 111. Plunger; 112. Concave spherical surface; 113. Slipper; 114. Convex spherical surface; 115. Sliding surface; 116. Plunger cavity; 117. Lightweight material; 118. Oil guide groove; 119. Anti-deformation part; 120. Welding part; 1 21. Damping hole; 122. Lubrication hole; 123. Retaining ring; 124. Clearance; 125. Oil guide hole; 201. Swash plate type axial piston pump; 202a. Pump housing; 202b. End cover; 203. Swash plate; 204. Distribution plate; 205. Oil port; 206. Drive shaft; 206a. Spline; 207a. Bearing; 207b. Bearing; 208. Cylinder block; 209. Cylinder hole; 210. Slipper plunger; 211. Plunger; 212. Concave spherical surface; 213. Slipper; 214. Convex spherical surface; 215. Sliding surface; 216. Plunger cavity; 217. Solid part; 218. Oil guide hole; 219. Dissolved resin; 220. Welding part; 221. Damping hole; 222. Anti-deformation part; 223. Perforation processing. DETAILED DESCRIPTION

[0065] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0066] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0067] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0068] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0069] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0070] The plunger for the hydraulic device and the hydraulic device of the present invention are characterized in that a lightweight material is embedded in the plunger cavity formed by the shaft portion of the plunger for the hydraulic device, and the lightweight material has an oil guide groove on the periphery, but the processing groove formed on the periphery of the lightweight material can be made into a spiral processing groove or multiple axial processing grooves.

[0071] Furthermore, the form of the plunger for a hydraulic device of the present invention can be applicable to a plunger for a hydraulic device of the type in which the convex spherical surface at the end of the plunger and the concave spherical surface of the shoe are freely combined to swing, and the sliding surface of the shoe slides on the slanted plate, and can also be applicable to a plunger for a hydraulic device of the type in which the concave spherical surface at the end of the plunger and the convex spherical surface of the shoe are freely combined to swing, and the sliding surface of the shoe slides on the slanted plate.

[0072] As the material of the lightweight material, various materials can be used, such as lightweight non-ferrous metal materials such as aluminum alloy, magnesium alloy, titanium alloy, lightweight ceramic materials such as porous ceramics and ceramic matrix composite materials, lightweight plastic materials such as carbon fiber reinforced plastic, glass fiber reinforced plastic, boron fiber reinforced plastic, aramid fiber reinforced plastic, etc. The processing groove formed on the outer peripheral surface of the lightweight material can also be formed by appropriate processing technology such as cutting and forming according to the properties of the material.

[0073] Lightweight materials, such as aluminum alloy and other lightweight non-ferrous metal materials. For example, the use of lathes for peripheral processing has the advantages of reducing man-hours and achieving precision. In addition, since processing grooves are formed on the peripheral surface of lightweight materials, deep holes can be drilled in a short time with strong tools, thus reducing man-hours. There is no need for special machines or proprietary technologies, heat setting in the plunger cavity, and no investment in new equipment.

[0074] Furthermore, peripheral machining can reduce man-hours and easily achieve precision, so the gap and leakage between the shoe and the swash plate can be accurately set, and the pressure regulating effect on the sliding surface of the swash plate and the shoe can be fully exerted, so that the plunger for the hydraulic device and the hydraulic device can be free of bite wear, the efficiency can be improved, the operation can be stable and high-speed, and the life of the machine can be extended.

[0075] Example 1

[0076] Figure 1 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 1). Figure 1In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 125-oil guide hole. The outer periphery of the lightweight material 117 is formed with a spiral processing groove, i.e., the oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0077] The cross section of the oil guide groove 118 is a square groove, and a spiral oil guide hole 125 is formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0078] Compared with the damping holes 121 at the end portions and the lubrication holes 122 of the sliding shoe 113 which are thin and short, the spiral oil guide holes 125 are longer and can form a very small square cross-section. Therefore, the clearance and leakage amount between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set through the adjustment effect of the spiral oil guide holes 125, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0079] Example 2

[0080] Figure 2 This is an explanatory diagram of a plunger for a hydraulic device according to the present invention (Example 2). Figure 2 In the embodiment, the cross section of the oil guide groove 118 is a square groove, and a plurality of axial oil guide holes 125 are formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The plurality of axial oil guide holes 125 are connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0081] Compared with the damping holes 121 at the end portions and the lubrication holes 122 of the sliding shoe 113 which are thin and short, the multiple axial oil guide holes 125 are longer and can form multiple very small square groove sections. Therefore, through the adjustment effect of the multiple axial oil guide holes 125, the gap and leakage between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0082] Example 3

[0083] Figure 3 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 3). Figure 3 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slip shoe, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 121-damping hole, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity of the plunger 111. The concave spherical surface 112 at the end of the plunger 111 is freely swingably combined with the convex spherical surface 114 of the slip shoe 113, and the sliding surface 115 of the slip shoe 113 slides on the slant plate 103. The spiral oil guide hole 125 is connected to the damping hole 121 of the slip shoe 113, and lubricating oil is supplied between the slant plate 103 and the sliding surface 115 of the slip shoe 113.

[0084] Compared with the damping hole 121 of the sliding shoe 113, which is a thin hole and shorter, the spiral oil guide hole 125 is longer and can form a very small square groove cross-section. Therefore, through the adjustment effect of the spiral oil guide hole 125, the gap and leakage between the sliding surface 115 of the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set, and the pressure between the sliding surface 115 of the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0085] Example 4

[0086] Figure 4 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 4). Figure 4 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slip shoe, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 121-damping hole, 125-oil guide hole. The outer periphery of the lightweight material 117 is formed with a plurality of axial oil guide grooves 118, which are fixed in the plunger cavity of the plunger 111. The concave spherical surface 112 at the end of the plunger 111 is combined with the convex spherical surface 114 of the slip shoe 113 to swing freely, and the sliding surface 115 of the slip shoe 113 slides on the slant plate 103.

[0087] The cross section of the oil guide groove 118 is a square groove, and a plurality of axial oil guide holes 125 are formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The plurality of axial oil guide holes 125 are connected to the damping hole 121 of the shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the shoe 113. Compared with the damping hole 121 of the shoe 113 being a thin hole and short, the plurality of axial oil guide holes 125 are long and can form a plurality of very small square groove cross sections. Therefore, the clearance and leakage between the swash plate 103 and the sliding surface 115 of the shoe 113 can be set through the adjustment effect of the plurality of axial oil guide holes 125, and the pressure between the swash plate 103 and the sliding surface 115 of the shoe 113 can be stably controlled.

[0088] Example 5

[0089] Figure 5 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 5). Figure 5 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0090] The cross section of the oil guide groove 118 is a triangular groove or a round bottom triangular groove, and the length of each side of the cross section can be the same. A spiral oil guide hole 125 is formed between the inner circumference of the plunger cavity 116 of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0091] Compared with the damping holes 121 at the end portions and the lubrication holes 122 of the sliding shoe 113, which are thin and short, the spiral oil guide holes 125 are longer and can easily form a very small triangular groove or a round-bottomed triangular groove cross section. Therefore, the clearance and leakage between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set through the adjustment effect of the spiral oil guide holes 125, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0092] Example 6

[0093] Figure 6 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 6). Figure 6 In the embodiment, the cross section of the oil guide groove 118 is a triangular groove or a round-bottomed triangular groove, and a plurality of axial oil guide holes 125 are formed between the oil guide groove 118 and the inner peripheral surface of the plunger cavity 116 of the plunger 111. The plurality of axial oil guide holes 125 are connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0094] Compared with the damping holes 121 at the end portions and the lubrication holes 122 of the sliding shoe 113 which are thin and short, the plurality of axial oil guide holes 125 are longer and can form a plurality of very small triangular grooves or round-bottomed triangular groove cross-sections. Therefore, through the adjustment effect of the plurality of axial oil guide holes 125, the gap and leakage amount between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0095] Example 7

[0096] Figure 7 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 7). Figure 7 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0097] The cross section of the oil guide groove 118 is a triangular groove with different inclinations, and the lengths of the sides of the cross section can be different. A spiral oil guide hole 125 is formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0098] Compared with the damping holes 121 at the end portions and the lubrication holes 122 of the sliding shoe 113, which are thin and short, the spiral oil guide holes 125 are longer and can easily form very small triangular cross-sections with different inclinations. Therefore, through the adjustment effect of the spiral oil guide holes 118, the gap and leakage between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0099] In addition, if the inclination angle of the triangular cross section is different, the length of each side of the cross section can be different. The pressing force Fp of the plunger 111 in the direction of the swash plate 103 and the breaking force Fb from the swash plate 103 will change, and the oil pressure balance of the sliding shoe 113 relative to the swash plate 103 will change. Therefore, not only the size and length of the oil guide hole 125 change, but also the different inclination angles of the oil guide groove 118 change, so that the gap and leakage between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be set more accurately, and the pressure between the swash plate 103 and the sliding surface 115 of the sliding shoe 113 can be stably controlled.

[0100] The present invention provides several different optional structural forms of the oil guide groove in the above embodiments, namely, a square groove, a triangular groove, a round-bottomed triangular groove, and a triangular groove with two sides of different inclinations on the cross section. The present invention does not limit the oil guide groove to the above structural forms. In other embodiments, an oil guide groove with a cross section of other structural shapes may also be used, such as a cross section of other polygons, rounded polygons, circles, and ellipses. These changes in the structural shapes of the oil guide grooves are all optional embodiments of the oil guide groove in the present invention.

[0101] Example 8

[0102] Figure 8 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 8). Figure 8 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 123-circuit ring, 124-gap, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0103] and Figure 1Compared with the first embodiment of the present invention, the difference is that in the invention of the eighth embodiment, the diameter of the lightweight material 117 is smaller than the inner diameter of the plunger cavity 116, and when it is fixed in the plunger cavity 116 by the snap ring 123, a gap 124 is formed, and lubricating oil is supplied into the gap. The gap 124 and the spiral groove 118 on the outer periphery of the lightweight material 117 are formed with very small cross-sectional areas, so that the regulating effect can be fully exerted compared with the damping hole 121 at the end of the plunger or the lubricating hole 122 of the sliding shoe 113. At the same time, by supplying lubricating oil into the gap 124, the vibration generated by the axis of the plunger 111 in the right angle direction can be suppressed, and stable operation can be achieved.

[0104] Example 9

[0105] Fig. 9 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 9). Fig. 9 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 123-circuit ring, 124-gap, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0106] The cross section of the oil guide groove 118 is a triangular groove or a round-bottomed triangular groove, and a spiral oil guide hole 125 is formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0107] and Figure 5 Compared with the fifth embodiment of the present invention, the difference is that in the invention of the ninth embodiment, the diameter of the light material 117 is smaller than the inner diameter of the plunger cavity 116, and when it is fixed in the plunger cavity 116 by the snap ring 123, a gap 124 is formed, and lubricating oil is supplied into the gap 124. The gap 124 and the spiral groove 118 on the outer periphery of the light material 117 are formed with very small cross-sectional areas, so that a more sufficient regulating effect is exerted than the damping hole 121 at the end of the plunger and the lubricating hole 122 of the shoe 113. At the same time, by supplying lubricating oil into the gap 124, the vibration generated by the axis of the plunger 111 in the right angle direction can be suppressed, and stable operation can be achieved.

[0108] Example 10

[0109] Fig.10 It is an explanatory diagram showing a plunger for a hydraulic device according to the present invention (Example 10). Fig.10 In the figure, 103-slant plate, 111-plunger, 112-concave spherical surface, 113-slipper, 114-convex spherical surface, 115-sliding surface, 116-plunger cavity, 117-lightweight material, 118-oil guide groove, 119-anti-deformation part, 120-welding part, 121-damping hole, 122-lubricating hole, 123-circuit ring, 124-gap, 125-oil guide hole. The outer periphery of the lightweight material 117 forms a spiral oil guide groove 118, which is fixed in the plunger cavity 116 of the plunger 111 and connected to the welding part 120 through the anti-deformation part 119. The convex spherical surface 114 at the end of the plunger 111 is combined with the concave spherical surface 112 of the slipper 113 to swing freely, and the sliding surface 115 of the slipper 113 slides on the slant plate 103.

[0110] The cross section of the oil guide groove 118 is a triangular groove with different inclinations, and a spiral oil guide hole 125 is formed between the inner peripheral surface of the plunger cavity 116 of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, and lubricating oil is supplied between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0111] and Figure 7 Compared with the embodiment 7 of the present invention, the difference is that in the invention of the embodiment 10, the diameter of the lightweight material 117 is smaller than the inner diameter of the plunger cavity 116, and when it is fixed in the plunger cavity 116 by the snap ring 123, a gap 124 is formed, and lubricating oil is supplied into the gap 124. The gap 124 and the oil guide groove 118 on the outer periphery of the lightweight material 117 are formed with very small cross-sectional areas, so that a more sufficient adjustment effect is exerted than the damping hole 121 at the end of the plunger and the lubricating hole 122 of the shoe 113. At the same time, by supplying lubricating oil into the gap 124, the vibration generated by the axis of the plunger 111 in the right angle direction can be suppressed, and stable operation can be achieved.

[0112] Embodiment 11

[0113] Fig.11 It is an explanatory diagram of Application Example 1 of the hydraulic device of the present invention. Fig.11 Application Example 1 is Example 11 in which the plunger for a hydraulic device of the present invention is applied to a hydraulic device. Fig.11 Among them, 101-swash plate axial piston pump, 102-pump housing, 103-swash plate, 104-port plate, 105-oil port, 106-drive shaft, 107-bearing, 108-cylinder block, 109-cylinder bore, 111-plunger, 112-concave spherical surface, 113-slip shoe, 114-convex spherical surface, 115-sliding surface, 117-lightweight material, 118-spiral oil guide groove.

[0114] exist Fig.11 In the swash plate type axial piston pump 101, a swash plate 103 is provided in one end of a pump housing 102, and a drive shaft 106 passes through the swash plate 103 on the axis of the pump housing 102 and is supported by a bearing 107 to rotate freely. A cylinder block 108 is mounted on the drive shaft 106, and a plurality of cylinder holes 109 arranged axially on the circumference of the cylinder block 108 are respectively embedded with plungers 111 that can slide freely. A convex spherical surface 114 is provided at the end of the plunger 111, and a concave spherical surface 112 arranged at one end of a sliding shoe 113 is embedded in the convex spherical surface 114, and the end of the concave spherical surface 112 is reduced in diameter, so that the plunger 111 can swing freely.

[0115] The sliding surface 115 provided at the other end of the sliding shoe 113 is slidably connected to the swash plate 103. The opposite surface of the swash plate 103 of the pump housing 102 is provided with a valve plate 104, which is slidably connected to the cylinder body 108. The valve plate 104 is provided with an oil port 105 for supplying or discharging pressurized oil to the cylinder hole 109.

[0116] Fig.11 The plunger 111 is used Figure 1 The plunger structure for the hydraulic device shown in Example 1 has a spiral oil guide hole 125 formed on the lightweight material 117 between the inner circumferential surface of the plunger cavity of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 at the end portion and the lubrication hole 122 of the sliding shoe 113, so as to supply lubricating oil between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0117] Fig.11 In the hydraulic device described, lubricating oil is supplied between the sliding shoe 113 of the plunger 111 and the swash plate 103 according to the set clearance and leakage amount to control the pressure on the lubrication surface, thereby ensuring continuous and stable operation. Fig.11 The hydraulic device described herein uses Figure 1 The hydraulic device of embodiment 1 uses a plunger, but it can also be used Figure 2 Embodiment 2, Figures 5 to 10 Plunger for hydraulic device of embodiments 5 to 10.

[0118] Example 12

[0119] Fig.12 It is an explanatory diagram of Application Example 2 of the hydraulic device of the present invention. Fig.12 Application Example 2 is Example 12 in which the plunger for a hydraulic device of the present invention is applied to a hydraulic device. Fig.12Among them, 101-swash plate type axial piston pump, 102a and 102b-pump housing, 103-swash plate, 104-distribution plate, 105-oil port, 106-drive shaft, 107a and 107b-bearings, 108-cylinder block, 109-cylinder bore, 111-plunger, 112-concave spherical surface, 113-slip shoe, 114-convex spherical surface, 115-sliding surface, 117-lightweight material, 118-spiral oil guide groove.

[0120] Fig.12 In the swash plate type axial piston pump 101, an end cover 102b is installed at the other end of a cylindrical pump housing 102a with one axial end closed. A swash plate 103 is arranged in one end of the pump housing 102a, and a drive shaft 106 passes through the swash plate 103 on the axis of the pump housing 102a and the end cover 102b, and can rotate freely through the support of bearings 107a and 107b.

[0121] A cylinder body 108 is mounted on the drive shaft 106. A plurality of cylinder holes 109 are axially arranged on the circumference of the cylinder body 108, and a plurality of freely slidable plungers 111 are respectively embedded in the cylinder holes 109. A concave spherical surface 112 is arranged at the end of the plunger 111, and a convex spherical surface 114 arranged at one end of a sliding shoe 113 is embedded in the concave spherical surface 112. The end of the concave spherical surface 112 is reduced in diameter, so that the plunger 110 is formed so that the plunger 110 can swing freely.

[0122] The sliding surface 115 provided at the other end of the sliding shoe 113 is slidably connected to the swash plate 103. The opposite surface of the swash plate 103 of the pump housing 102a is provided with a valve plate 104, which is slidably connected to the cylinder block 108. The valve plate 104 is provided with an oil port 105 for supplying or discharging pressurized oil to or from the cylinder hole 109.

[0123] Fig.12 The plunger 111 adopts Figure 3 The plunger structure for the hydraulic device shown in Example 3 has a spiral oil guide hole 125 formed on the lightweight material 117 between the inner circumferential surface of the plunger cavity of the plunger 111. The spiral oil guide hole 125 is connected to the damping hole 121 of the sliding shoe 113 to supply lubricating oil between the swash plate 103 and the sliding surface 115 of the sliding shoe 113.

[0124] exist Fig.12 In the hydraulic device described, lubricating oil is supplied between the sliding shoe 113 of the plunger 111 and the swash plate 103 according to the set clearance and leakage amount to control the pressure on the lubrication surface, thereby ensuring continuous and stable operation. Fig.12 The hydraulic device described in the present invention adopts Figure 3 The hydraulic device of embodiment 3 uses a plunger, but it can also be used Figure 4 The plunger for a hydraulic device of embodiment 4, furthermore, Figures 5 to 10The structure of the plunger for hydraulic device of embodiments 5 to 10 can also be applied to Figure 3 The plunger 111 and the sliding shoe 113 of the third embodiment are used as a plunger in a hydraulic device.

[0125] The invention of the plunger for a hydraulic device and the invention of the hydraulic device of the present invention can be applied to hydraulic devices such as hydraulic pumps and hydraulic motors, and can be used as a punching machine or a pressurizing device in a factory using a hydraulic device, a freight elevator, a lifting power for various small machines, construction machinery or loading and unloading machinery, such as the operation of the operating mechanical parts of an electric shovel or a trailer, automobile brakes, aircraft rudder operation, and sluice gate switches, and other fields.

[0126] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A plunger for a hydraulic device, configured to use a plurality of plungers for the hydraulic device to reciprocate in the axial direction relative to the swash plate to act as a pump, characterized in that: The end portion has the above-mentioned swash plate and a shoe sliding on the swash plate surface, a light material is embedded in the plunger cavity formed by the shaft portion of the plunger for the hydraulic device, and the outer periphery of the light material has an oil guide groove, and lubricating oil is supplied between the sliding surface of the end portion of the shoe and the above-mentioned swash plate through an oil guide hole formed between the above-mentioned oil guide groove and the inner peripheral surface of the above-mentioned plunger cavity, so that the pressure between the above-mentioned swash plate and the sliding surface of the shoe can be controlled by adjusting the parameters of the above-mentioned oil guide hole itself, and the gap and leakage amount between the above-mentioned swash plate and the sliding surface of the shoe can be adjusted; The oil guide groove is a machined groove formed on the cylindrical outer peripheral surface of the lightweight material. The oil guide hole supplies lubricating oil to the sliding surface of the end of the shoe and the swash plate according to a preset oil film thickness and controlled oil pressure, forming a specified flow path length and a specified flow path cross-sectional area, and the cross-section of the oil guide groove is a square groove, a rounded polygonal groove, a circular groove, an elliptical groove, a triangular groove or a round-bottomed triangular groove.

2. A hydraulic device, which is a hydraulic device in which a plurality of hydraulic devices use plungers to reciprocate a swash plate and play the role of an oil pump, characterized in that: The plunger for a hydraulic device as described in claim 1 has the above-mentioned swash plate and a sliding shoe at its end, and a lightweight material forming an oil guide groove is fixed to the outer periphery in the plunger cavity formed by the shaft portion, and lubricating oil is supplied between the sliding surface of the end of the sliding shoe and the above-mentioned swash plate through the oil guide hole formed between the above-mentioned oil guide groove and the inner peripheral surface of the above-mentioned plunger cavity.

3. The hydraulic device according to claim 2, characterized in that: The above-mentioned oil guide groove is a machined groove formed on the cylindrical outer peripheral surface of the above-mentioned lightweight material. The above-mentioned oil guide hole supplies lubricating oil to the sliding surface of the end of the above-mentioned shoe and the above-mentioned inclined plate according to the preset oil film thickness and controlled oil pressure, forming a specified flow path length and a specified flow path cross-sectional area.

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