Hydraulic oil cylinder and engineering machinery

Abstract

The utility model relates to a hydraulic oil cylinder, in particular to a hydraulic oil cylinder and engineering machinery, which comprises a cylinder barrel, a piston positioned in the cylinder barrel and a piston rod with a first end fixedly connected with the piston, and a second end of the piston rod extends out of an inner hole of a guide sleeve fixed at the end part of the cylinder barrel. The first end of the piston rod is sleeved with a buffering sleeve used for being matched with the guide sleeve for buffering. A plurality of flat positions are arranged on the outer circumferential face of the buffering sleeve in the circumferential direction at intervals, and each flat position is formed by connecting a plurality of flat position planes which are sequentially connected in an intersecting mode in the axial direction. In the utility model, the flat position consists of a plurality of flat position planes, so that the flat position has a multi-slope characteristic, the buffering is more stable, the buffering effect is more controllable, the oil cylinder runs more stably, and the problems of shaking and the like are solved.

Description

Technical Field

[0001] This utility model relates to a hydraulic cylinder, and more specifically, to a hydraulic cylinder and engineering machinery. Background Technology

[0002] Hydraulic cylinders are widely used in construction machinery, where they achieve the machine's functions through the reciprocating motion of a piston rod. To avoid strong impacts or vibrations at the end of the cylinder's stroke, ensure smooth operation of the hydraulic system, reduce overall machine noise, increase operator comfort, and extend the service life of the machine and the hydraulic system cylinders, it is necessary to buffer and slow down the piston rod before it reaches the end of its stroke, allowing the piston rod to move slowly to the end of its stroke.

[0003] Currently, most hydraulic cylinder buffer structures used in the industry employ a buffer sleeve mounted on the piston rod. A variable cross-section is set on the outer circumference of the buffer sleeve, decreasing in size from large to small, and evenly distributed around its outer circumference. Buffering is achieved through the gap between the outer circumference of the buffer sleeve and the inner hole of the cylinder head, allowing the cylinder speed to decrease to zero at the end of its stroke. If the gap between the buffer sleeve and the inner hole of the cylinder head is too small, it will lead to slow pressure release and excessively high pressure, resulting in cylinder expansion and oil leakage, reducing the cylinder's service life. If the gap is too large, it will lead to excessively rapid pressure release, resulting in insufficient buffering time or no buffering effect, causing impacts in the cylinder components, producing vibration and noise. This makes the cylinder buffering effect difficult to control, leading to defective cylinder heads and buffer sleeves, resulting in excessive costs; and even affecting the safety and service life of the hydraulic cylinder. Utility Model Content

[0004] The technical problem to be solved by this utility model is the disadvantage of the deceleration and buffering at the end of the piston rod stroke of the hydraulic cylinder, and a hydraulic cylinder and engineering machinery are provided.

[0005] The technical solution of this utility model to achieve its purpose is: a hydraulic cylinder, which includes a cylinder barrel, a piston located inside the cylinder barrel, a piston rod whose first end is fixedly connected to the piston, and a piston rod whose second end extends out from the inner hole of a guide sleeve fixed at the end of the cylinder barrel. The first end of the piston rod is fitted with a buffer sleeve for cooperating with the guide sleeve for buffering. The outer circumferential surface of the buffer sleeve is provided with a plurality of flat positions evenly distributed in the circumferential direction, and each flat position is composed of a plurality of flat position planes that are sequentially connected in the axial direction.

[0006] In the hydraulic cylinder of this invention, all the flat planes in the same flat position are arranged with a common mid-plane. Furthermore, there are three flat planes in the same flat position, wherein the angle between the middle flat plane and the axis of the guide sleeve is greater than the angle between the flat planes at both ends and the axis of the guide sleeve.

[0007] In the hydraulic cylinder of this invention, the buffer sleeve is floatingly mounted on the piston rod. Furthermore, the axial floating clearance of the buffer sleeve on the piston rod is 0.5 mm.

[0008] In the hydraulic cylinder of this utility model, the first end of the piston rod has a stepped structure, which has a piston mounting section for fixing the piston and a buffer sleeve mounting section for fitting the buffer sleeve with a diameter larger than the piston mounting section. The length of the buffer sleeve mounting section is equal to the sum of the length of the buffer sleeve and the axial floating clearance.

[0009] In the hydraulic cylinder of this utility model, the buffer sleeve has multiple radially penetrating oil passage grooves, and each oil passage groove is circumferentially evenly distributed on the end face of the buffer sleeve that abuts against the piston.

[0010] In the hydraulic cylinder of this utility model, a pressure relief oil passage is provided on the guide sleeve. One end of the pressure relief oil passage is located at the end of the guide sleeve and communicates with the small cavity of the cylinder, and the other end of the pressure relief oil passage is communicated with the interface of the small cavity of the cylinder.

[0011] In the hydraulic cylinder of this utility model, when the piston rod is at the end of its stroke, the inner end face of the guide sleeve abuts against the piston, and multiple radially penetrating starting grooves are provided on the inner end face of the guide sleeve, with each starting groove being evenly distributed circumferentially on the inner end face of the guide sleeve.

[0012] The technical solution of this utility model to achieve its purpose is: an engineering machine having the aforementioned hydraulic cylinder. This engineering machine can be, but is not limited to, loaders, excavators, graders, etc.

[0013] Compared with the prior art, in this utility model, the flat part on the buffer sleeve makes the gap between the buffer sleeve and the guide sleeve gradually decrease during the piston rod extension buffering process. The flat part is composed of multiple flat planes, which gives it a multi-slope characteristic, making the buffering more stable and the buffering effect more controllable. The cylinder runs more smoothly and will not have problems such as shaking. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the hydraulic cylinder of this utility model.

[0015] Figure 2 This is a schematic diagram of the buffer sleeve in the hydraulic cylinder of this utility model.

[0016] Figure 3 yes Figure 2 Cross-sectional view along line A.

[0017] Figure 4 This is a partially enlarged cross-sectional view of the buffer sleeve in the hydraulic cylinder of this utility model.

[0018] Figure 5 This is a schematic diagram of the guide sleeve in the hydraulic cylinder of this utility model.

[0019] Figure 6 This is a schematic diagram of the inner end structure of the guide sleeve in the hydraulic cylinder of this utility model.

[0020] Component names and serial numbers in the diagram:

[0021] Cylinder 1, Small cavity interface 11, Small cylinder cavity 12, Piston rod 2, Piston 3, Guide sleeve 4, Pressure relief oil passage 41, Starting groove 42, Oil passage hole 43, Buffer sleeve 5, Buffer starting end 51, Buffer ending end 52, Flat position 53, Front flat position plane 531, Middle flat position plane 532, Rear flat position plane 533, Oil passage groove 54. Detailed Implementation

[0022] The specific implementation plan is described below with reference to the attached diagram.

[0023] like Figure 1 As shown, the hydraulic cylinder includes a cylinder barrel 1, a piston 3 located inside the cylinder barrel 1, and a piston rod 2 whose first end is fixedly connected to the piston 3. The second end of the piston rod 2 extends out from the inner hole of the guide sleeve 4 fixed at the end of the cylinder barrel 1. The first end of the piston rod 2 is fitted with a buffer sleeve 5 for cooperating with the guide sleeve 4 for buffering.

[0024] The guide sleeve 4 is fixedly connected to the cylinder 1 and has multiple radial oil passage holes 43. The small cavity interface 11 on the cylinder 1 is connected to the inner hole of the guide sleeve 4 through the oil passage holes 43 on the guide sleeve 4, and then connected to the small cavity 12 of the oil cylinder.

[0025] The buffer sleeve 5 is installed on the piston rod 2. When the piston rod 2 extends outward through the guide sleeve 4 and approaches the end of the piston rod 4's stroke, the buffer sleeve 5 enters the inner hole of the guide sleeve 4. Because the buffer sleeve 5 enters the inner hole of the guide sleeve 4, the flow area of ​​the oil flowing out of the small cylinder chamber 12 through the inner hole of the guide sleeve 5 is reduced, the speed of the oil flowing out of the small cylinder chamber 12 decreases, and the extension speed of the piston rod 2 slows down, thus playing a buffering role at the end of the piston rod's extension stroke.

[0026] The buffer sleeve 5 is cylindrical and fits onto the piston rod 2. Its outer diameter is smaller than the inner diameter of the guide sleeve 4. When the buffer sleeve 5 enters the guide sleeve 4, there is a gap between the buffer sleeve 5 and the guide sleeve 4. This gap connects the small cavity 12 of the hydraulic cylinder and the oil passage hole 43 on the guide sleeve 4. The end of the buffer sleeve 5 opposite to the piston 3 is the buffer termination end 52, and the other end is the buffer initiation end 51. When the buffer initiation end 51 of the buffer sleeve enters the inner hole of the guide sleeve 4, the piston rod 2 extends and approaches the end of its stroke, and the buffering begins.

[0027] After the buffer sleeve 5 extends into the inner hole of the guide sleeve 4, the rate at which the oil flows out of the small cavity 12 of the hydraulic cylinder depends on the oil flow gap (area) between the inner wall of the buffer sleeve 5 and the guide sleeve 4. Generally, as the depth of the buffer sleeve 5 extending into the guide sleeve 4 increases, the oil flow area between the guide sleeve 4 and the buffer sleeve 5 gradually decreases. A flat section 53 is provided on the buffer sleeve 5 to facilitate the design and determination of the XA relationship curve between the length X of the buffer sleeve 5 extending into the guide sleeve 4 and the oil flow area A.

[0028] In this embodiment, the outer circumferential surface of the buffer sleeve 5 is provided with a plurality of flat sections 53 at circumferential intervals. Each flat section 53 is composed of a plurality of flat section planes that are sequentially connected in the axial direction. The flat sections are evenly distributed circumferentially on the circumferential surface of the buffer sleeve 5, or are arranged in a centrally symmetrical manner with the buffer sleeve axis as the center on the circumferential surface of the buffer sleeve 5.

[0029] All planes in the same flat section are arranged on a common mid-plane. Optionally, there are three planes in the same flat section, wherein the angle between the middle plane and the axis of the guide sleeve is greater than the angle between the two end planes and the axis of the guide sleeve.

[0030] like Figures 2 to 4 As shown, the three flat planes forming the flat section on the buffer sleeve 5 are, from the buffer start end to the buffer end, the front flat plane 531, the middle flat plane 532, and the rear flat plane 533. These three planes intersect and connect sequentially, and are arranged with a common mid-plane. The front flat plane 531 is approximately parallel to the guide sleeve axis, the angle between the middle flat plane 532 and the guide sleeve axis is greater than the angle between the front flat plane 531 and the guide sleeve axis, and the angle between the rear flat plane 533 and the guide sleeve axis is smaller than the angle between the middle flat plane 532 and the guide sleeve axis. Through these three flat planes, the fitted XA relationship curve approximates a parabola, making the buffering smoother and the buffering effect more controllable, resulting in smoother cylinder operation.

[0031] Optionally, in this embodiment of the hydraulic cylinder, the buffer sleeve 5 is floatingly mounted on the piston rod 2. Further, the axial floating clearance of the buffer sleeve 5 on the piston rod is 0.5 mm. The first end of the piston rod 2 has a stepped structure, comprising a piston mounting section for fixed connection to the piston 3 and a buffer sleeve mounting section for fitting the buffer sleeve 5. The buffer sleeve 5 is fitted onto the buffer sleeve mounting section on the piston rod. The piston is fixedly mounted on the piston mounting section of the piston rod by threaded engagement or nut locking, thus limiting the buffer sleeve. The length of the buffer sleeve mounting section is equal to the sum of the length of the buffer sleeve and the axial floating clearance. Due to the steps and bolts at both ends, the buffer sleeve achieves floating installation, allowing it to move freely 0.5 mm axially along the piston rod on the buffer sleeve mounting section. In practical applications, the buffer sleeve also has a certain amount of floating in the radial direction. Setting the buffer sleeve 5 to a floating installation allows it to self-adjust, preventing the buffer sleeve from scraping against the guide sleeve.

[0032] Optionally, the buffer sleeve 5 has multiple radially penetrating oil passages 54, each oil passage 54 being circumferentially spaced on the end face of the buffer sleeve 5 that abuts against the piston 3. The oil passages 54 can be evenly distributed circumferentially on the end face or centrally symmetrically arranged. The oil passages 54 can connect the inner hole of the buffer sleeve 5 with the small cavity 12 of the oil cylinder, facilitating the entry and exit of oil in the inner hole of the buffer sleeve 5 when it adaptively adjusts its posture.

[0033] Optionally, when the piston rod 2 is at the end of its stroke, the inner end face of the guide sleeve 4 abuts against the piston 3. Multiple radially penetrating starting grooves 42 are provided on the inner end face of the guide sleeve 4. These starting grooves 42 are circumferentially spaced on the inner end face of the guide sleeve 4. The starting grooves 42 can be evenly distributed circumferentially on the end face or centrally symmetrically arranged. When the piston rod 2 is at the end of its stroke and begins to retract, pressurized oil enters the small cavity interface 11. This pressurized oil flows through the gap between the guide sleeve 4 and the buffer sleeve 5 to the starting grooves 42. The starting grooves 42 increase the area of ​​the oil acting on the piston 3, allowing the piston rod 2 to retract quickly.

[0034] Optionally, such as Figure 1 Figure 5 As shown, the guide sleeve 4 is provided with a pressure relief oil passage 41. One end of the pressure relief oil passage 41 is located at the end of the guide sleeve 4 and communicates with the small cavity 12 of the oil cylinder. The other end of the pressure relief oil passage 41 is communicated with the small cavity interface 11 of the oil cylinder. The pressure relief oil passage 41 on the guide sleeve 4 is provided to reduce the buffering pressure of the small cavity 12 of the oil cylinder during buffering, so as to prevent the oil cylinder from expanding due to excessive buffering pressure.

[0035] This embodiment also provides an engineering machine having the aforementioned hydraulic cylinder. This engineering machine can be, but is not limited to, loaders, excavators, graders, etc.

Claims

1. A hydraulic cylinder, comprising a cylinder barrel, a piston located within the cylinder barrel, a piston rod with its first end fixedly connected to the piston, and a second end of the piston rod extending from the inner hole of a guide sleeve fixed to the end of the cylinder barrel, wherein the first end of the piston rod is fitted with a buffer sleeve for cooperating with the guide sleeve for cushioning; characterized in that, The outer circumferential surface of the buffer sleeve is provided with multiple flat sections evenly spaced in the circumferential direction. Each flat section is composed of multiple flat section planes that are connected in sequence in the axial direction.

2. The hydraulic cylinder according to claim 1, characterized in that, The planes of each of the flat positions in the same flat position are arranged with a common mid-plane.

3. The hydraulic cylinder according to claim 1, characterized in that, The same flat position has three flat position planes, wherein the angle between the flat position plane in the middle of the displacement and the axis of the guide sleeve is greater than the angle between the flat position planes at both ends and the axis of the guide sleeve.

4. The hydraulic cylinder according to any one of claims 1 to 3, characterized in that, The buffer sleeve is floatingly mounted on the piston rod.

5. The hydraulic cylinder according to claim 4, characterized in that, The axial floating clearance of the buffer sleeve on the piston rod is 0.5 mm.

6. The hydraulic cylinder according to claim 5, characterized in that, The first end of the piston rod has a stepped structure, which has a piston mounting section for fixed connection of the piston and a buffer sleeve mounting section for sleeved with the buffer sleeve and with a diameter larger than the piston mounting section. The length of the buffer sleeve mounting section is equal to the sum of the length of the buffer sleeve and the axial floating clearance.

7. The hydraulic cylinder according to claim 6, characterized in that, The buffer sleeve has multiple radially penetrating oil grooves, each of which is circumferentially spaced and evenly distributed on the end face of the buffer sleeve that abuts against the piston.

8. The hydraulic cylinder according to claim 1, characterized in that, The guide sleeve is provided with a pressure relief oil passage. One end of the pressure relief oil passage is located at the end of the guide sleeve and communicates with the small cavity of the oil cylinder. The other end of the pressure relief oil passage is communicated with the small cavity interface of the oil cylinder.

9. The hydraulic cylinder according to claim 8, characterized in that, When the piston rod is at the end of its stroke, the inner end face of the guide sleeve abuts against the piston, and multiple radially penetrating starting grooves are provided on the inner end face of the guide sleeve, with each starting groove being evenly distributed circumferentially on the inner end face of the guide sleeve.

10. An engineering machinery, characterized in that, It has a hydraulic cylinder as described in any one of claims 1 to 9.

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