Quick-change oil cylinder, quick-change device and engineering machinery

Abstract

The invention discloses a quick-change oil cylinder which comprises a cylinder barrel, a lining, a piston rod and a piston. The piston rod is of a stepped shaft structure. The outer side of the bushing is of a stepped shaft structure, and the inner side is of a stepped hole structure; the piston rod coaxially penetrates through the bushing and the piston to form an oil cylinder core body assembly, and the bushing and the piston rod can relatively move in the axial direction; the oil cylinder core assembly is coaxially arranged in the cylinder barrel in a penetrating mode, and the oil cylinder core assembly and the cylinder barrel can move relatively in the axial direction. Furthermore, the invention discloses a quick-change device using the quick-change oil cylinder. The engineering machinery uses the quick-change oil cylinder or the quick-change device. The quick-change oil cylinder is simple in process structure and convenient to produce and machine. The quick-change device is compact in structure and saves the installation and arrangement space, meanwhile, the piston rod of the quick-change oil cylinder is directly connected with the installation hole of the quick-change machine tool, the coaxiality is high, the centering performance is good, the clamping stagnation problem is avoided, and the quick-change machine tool is more convenient and faster to replace. And the problem that the joint of the quick-change oil cylinder piston rod and the quick-change pin shaft is broken and damaged is solved.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery, and more particularly to a quick-change hydraulic cylinder, a quick-change device, and engineering machinery. Background Technology

[0002] Loaders are a type of engineering machinery widely used in various working conditions. By changing different attachments, they can perform a variety of different tasks, such as earthmoving, loading and unloading, material clearing, timber grabbing, hay clamping, and snow removal. Currently, most loader manufacturers offer hydraulic quick-change devices for rapidly changing loader attachments. Using hydraulic quick-change devices can reduce manual labor intensity and save manpower. Most existing hydraulic quick-change devices employ a quick-change cylinder to accelerate the replacement of the pivot pin. However, this method typically has the following problems:

[0003] 1. The solution of using an external hydraulic cylinder to quickly change the pin requires a longer installation space, which is inconvenient for the layout of quick-change devices with compact structures and limited space.

[0004] 2. The solution of using an external quick-change pin on the hydraulic cylinder has low coaxiality between the hydraulic cylinder and the quick-change pin. When the piston rod of the quick-change hydraulic cylinder extends or retracts, the quick-change pin is not properly aligned with the mounting hole of the quick-change tool, which makes the quick-change pin prone to jamming and inconvenient to change tools.

[0005] 3. The solution of using an external quick-change pin on the hydraulic cylinder is prone to breakage and damage at the connection between the hydraulic cylinder piston rod and the quick-change pin.

[0006] 4. In the existing technology, quick-change hydraulic cylinders are usually bidirectional telescopic symmetrical structures. Because a bidirectional limiting device needs to be set in the middle of the cylinder barrel, the quick-change hydraulic cylinder has a complex structure and is difficult to process.

[0007] Therefore, it is necessary to develop new technologies specifically to overcome the above problems. Summary of the Invention

[0008] Purpose of the invention: To address the shortcomings and defects of existing technologies, this invention provides a quick-change cylinder, a quick-change device, and engineering machinery. The quick-change cylinder uses a limiting sleeve for positioning, which simplifies the process and makes it easier to manufacture. Simultaneously, the quick-change device eliminates the quick-change pin, using the quick-change cylinder piston rod to directly connect with the quick-change tool mounting hole. This saves installation space and solves the problems of inconvenient tool replacement due to low coaxiality and breakage at the connection between the cylinder piston rod and the quick-change pin.

[0009] Technical solution: The technical solution of this invention is as follows:

[0010] In one aspect, a quick-change hydraulic cylinder is provided, comprising: a cylinder barrel, a bushing, a piston rod, and a piston.

[0011] The piston rod has a stepped shaft structure.

[0012] The outer side of the bushing has a stepped shaft structure, and the inner side has a stepped hole structure.

[0013] The piston rod coaxially passes through the bushing and piston to form the cylinder core assembly. The bushing and piston rod can move relative to each other along the axial direction. The cylinder core assembly is coaxially placed inside the cylinder barrel. The cylinder core assembly and the cylinder barrel can move relative to each other along the axial direction.

[0014] The piston divides the cylinder into the large chamber and the small chamber.

[0015] Furthermore, the cylinder barrel of the quick-change hydraulic cylinder is provided with a large cavity oil port and a small cavity oil port, the large cavity oil port being connected to the large cavity of the hydraulic cylinder and the small cavity oil port being connected to the small cavity of the hydraulic cylinder.

[0016] The piston moves axially between the large chamber oil port and the small chamber oil port.

[0017] Furthermore, the piston rod of the quick-change hydraulic cylinder includes: a piston rod major diameter shaft, a piston rod minor diameter shaft, and a piston rod stepped shaft diameter-changing limiting surface.

[0018] Furthermore, the quick-change cylinder bushing includes: a bushing major diameter shaft, a bushing minor diameter shaft, a bushing major diameter hole, a bushing minor diameter hole, a bushing stepped hole diameter limiting surface, a bushing major diameter shaft end face, and a bushing minor diameter shaft end face; the bushing minor diameter shaft and the bushing minor diameter hole are located at the same end, and the bushing major diameter shaft and the bushing major diameter hole are located at the same end.

[0019] Furthermore, the radially inner circumferential surface of the small-diameter bore of the quick-change cylinder bushing contacts the radially outer circumferential surface of the small-diameter shaft of the piston rod, and the radially inner circumferential surface of the large-diameter bore of the bushing contacts the radially outer circumferential surface of the large-diameter shaft of the piston rod; the piston and piston rod are fixedly connected to form a piston rod assembly, with the piston located at the end of the small-diameter shaft of the piston rod; the radially outer circumferential surface of the piston contacts the radially inner circumferential surface of the cylinder, and the radially outer circumferential surface of the bushing's large-diameter shaft contacts the radially inner circumferential surface of the cylinder, forming a gap between the radially outer circumferential surface of the bushing's small-diameter shaft and the radially inner circumferential surface of the cylinder; the end face of the bushing's large-diameter shaft and the end face of the piston rod's large-diameter shaft are close to the end of the cylinder.

[0020] Furthermore, the quick-change cylinder bushing, the bushing stepped bore diameter changing limiting surface, and the piston rod stepped shaft diameter changing limiting surface work together to control the axial movement stroke of the piston rod assembly composed of the piston and piston rod.

[0021] When the piston rod assembly, consisting of the piston and piston rod, moves axially toward the bushing, once the end face of the piston's small cavity contacts the end face of the bushing's minor diameter shaft, the piston rod assembly cannot move any further toward the bushing in the axial direction.

[0022] When the piston rod assembly, consisting of the piston and piston rod, moves axially away from the bushing, and the piston rod stepped shaft diameter-changing limiting surface contacts the bushing stepped hole diameter-changing limiting surface, the piston rod assembly, consisting of the piston and piston rod, can no longer move axially away from the bushing.

[0023] Furthermore, the quick-change cylinder is characterized in that there is an area difference between the piston end face and the bushing minor diameter shaft end face, with the piston end face area being larger than the bushing minor diameter shaft end face area.

[0024] Furthermore, the quick-change hydraulic cylinder is characterized in that the piston rod can also be a split structure, with the minor diameter shaft and the major diameter shaft of the piston rod fixedly assembled and connected as a whole to form the piston rod, and the diameter of the major diameter shaft of the piston rod being larger than the diameter of the minor diameter shaft of the piston rod.

[0025] The piston rod is provided with a piston rod end face chamfer to facilitate the alignment and connection of the piston rod major diameter shaft with the quick-change tool. The piston rod end face chamfer is located at the end of the piston rod major diameter shaft near the end of the cylinder.

[0026] The piston rod is also equipped with a clamping structure for assembly and tightening.

[0027] Furthermore, the piston rod of the quick-change cylinder is provided with a middle diameter shaft on its major diameter shaft. The middle diameter shaft is located near the piston rod stepped shaft diameter-changing limiting surface. The diameter of the middle diameter shaft is larger than the diameter of the minor diameter shaft and smaller than the diameter of the major diameter shaft. The middle diameter shaft ensures that after the piston rod major diameter shaft and the piston rod minor diameter shaft are assembled as one unit, the piston rod major diameter shaft can still pass through the bushing's large inner hole axially.

[0028] The second aspect provides a quick-change device, which includes: the quick-change cylinder and limit sleeve, quick-change frame, and boom described in the first aspect.

[0029] The quick-change cylinder barrel is fixedly mounted on the quick-change frame; the outer side of the limiting sleeve coaxially passes through the boom and the quick-change cylinder in sequence, and the limiting sleeve and the quick-change cylinder barrel are fixedly connected together. The limiting sleeve and the boom can rotate circumferentially. The quick-change frame and the limiting sleeve work together to restrict the axial movement of the boom; the piston rod major diameter shaft coaxially passes through the inner side of the limiting sleeve, and the piston rod major diameter shaft and the limiting sleeve can move axially.

[0030] The quick-change cylinder is provided with a structure for connecting with the limit sleeve and the quick-change frame.

[0031] The limiting sleeve is provided with a structure for fixed connection with the quick-change oil cylinder.

[0032] The quick-change frame is provided with a structure for fixed connection with the quick-change hydraulic cylinder.

[0033] The boom is provided with a structure for connecting to the limiting sleeve.

[0034] Furthermore, the quick-change cylinder of the quick-change device has an internal thread on the radially inner side of its cylinder end that connects to the limiting sleeve, and an external thread on the radially outer side of its cylinder end that connects to the quick-change frame.

[0035] Furthermore, the quick-change device is characterized in that the quick-change frame includes: a quick-change frame mounting threaded hole and an outer surface of the quick-change frame.

[0036] Furthermore, the boom of the quick-change device includes: a boom mounting hole, an inner side of the boom mounting hole, and an outer side of the boom mounting hole.

[0037] Furthermore, the limiting sleeve of the quick-change device includes: a large-diameter shaft of the limiting sleeve, a small-diameter shaft of the limiting sleeve, an inner hole of the limiting sleeve, an inner end face of the large-diameter shaft of the limiting sleeve, an outer end face of the large-diameter shaft of the limiting sleeve, an end face of the small-diameter shaft of the limiting sleeve, and a connecting thread for the limiting sleeve.

[0038] The outer side of the limiting sleeve has a stepped shaft structure, the connecting thread of the limiting sleeve is close to the end face of the small diameter shaft of the limiting sleeve, and the large diameter shaft of the limiting sleeve is larger than the diameter of the boom mounting hole.

[0039] The minor diameter shaft of the limiting sleeve passes coaxially through the boom mounting hole and the quick-change cylinder barrel in sequence; the radially outer circumferential surface of the minor diameter shaft of the limiting sleeve contacts the radially inner circumferential surface of the boom mounting hole, and the minor diameter shaft of the limiting sleeve is coaxial with the boom mounting hole and can rotate circumferentially; the limiting sleeve is fixedly set on the quick-change cylinder barrel, and is fixedly connected to the internal thread of the cylinder barrel end through the thread at the end of the minor diameter shaft of the limiting sleeve; the radially inner circumferential surface of the inner hole of the limiting sleeve contacts the radially outer circumferential surface of the major diameter shaft of the piston rod, and the piston rod can move axially along the limiting sleeve.

[0040] Furthermore, the limiting sleeve of the quick-change device restricts the axial movement stroke of the piston rod assembly composed of the piston and piston rod at its small-diameter shaft end.

[0041] The depth to which the end face of the limiting sleeve extends into the cylinder barrel of the quick-change cylinder limits the outward movement of the quick-change cylinder bushing.

[0042] When the piston contacts the end face of the bushing's minor diameter shaft and the end face of the bushing's major diameter shaft contacts the end face of the limit sleeve's minor diameter shaft, the major diameter shaft of the bushing must not block the small cavity oil port and must ensure that the small cavity oil port can connect with the gap formed by the radial outer side of the bushing's minor diameter shaft and the radial inner side of the cylinder. In addition, the piston rod of the quick-change cylinder extends outward to its maximum length and ensures that the extension length of the piston rod's major diameter shaft's outer end face exceeds the outer end face of the quick-change tool's mounting connection plate, so that the piston rod can fully mesh with the quick-change tool.

[0043] When the end face of the bushing's large diameter shaft contacts the end face of the limiting sleeve's small diameter shaft and the piston rod's stepped shaft diameter-changing surface contacts the bushing's stepped hole diameter-changing limiting surface, the piston must not obstruct the large chamber oil port. The piston is positioned between the large chamber oil port and the small chamber oil port of the oil cylinder. The large chamber oil port and the small chamber oil port act on different sides of the piston, and the piston rod retracts inward to its shortest length, ensuring that the outer end face of the piston rod's large diameter shaft does not exceed the inner end face of the quick-change tool's mounting connection plate. The piston rod can be completely detached from the quick-change tool.

[0044] Furthermore, the large-diameter shaft end of the limiting sleeve of the quick-change device restricts the axial movement of the boom and the quick-change tool.

[0045] The distance between the inner end face of the large diameter shaft of the limiting sleeve and the outer side of the quick-change bracket is greater than the thickness of the boom mounting hole. The inner side of the boom mounting hole is close to the outer side of the quick-change bracket, and the outer side of the boom mounting hole is close to the inner end face of the large diameter shaft of the limiting sleeve. The outer side of the quick-change bracket and the inner end face of the large diameter shaft of the limiting sleeve work together to restrict the axial movement of the boom.

[0046] The outer end face of the locating sleeve shall not extend beyond the inner end face of the quick-change tool mounting plate, and the outer end face of the locating sleeve shall restrict the axial movement of the quick-change tool.

[0047] Furthermore, the quick-change device also includes a sealing ring.

[0048] Furthermore, the limiting sleeve of the quick-change device further includes: an outer oil groove, an inner oil groove, an oil passage hole, a lubrication channel, and a sealing ring mounting groove; the outer oil groove is disposed on the outer wall surface of the small diameter shaft of the limiting sleeve, the inner oil groove is disposed on the inner wall surface of the inner hole of the limiting sleeve, the limiting sleeve is radially provided with an oil passage hole, the oil passage hole connects the inner oil groove and the outer oil groove of the limiting sleeve, the lubrication channel is disposed on the inner wall surface of the inner hole of the limiting sleeve, and the lubrication channel is connected to the inner oil groove, and the sealing ring mounting groove is disposed at one end of the large diameter shaft of the limiting sleeve, coaxial with the inner hole of the limiting sleeve, and the diameter of the sealing ring mounting groove is larger than the diameter of the inner hole of the limiting sleeve.

[0049] Furthermore, the boom of the quick-change device is provided with a boom mounting hole lubrication channel, which is connected to the boom mounting hole.

[0050] Furthermore, the sealing ring of the quick-change device is coaxially fixed on the sealing ring mounting groove of the limiting sleeve. The radially outer circumferential surface of the sealing ring is connected to the radially inner circumferential surface of the sealing ring mounting groove of the limiting sleeve. The radially inner circumferential surface of the sealing ring is connected to the radially outer circumferential surface of the piston rod's major diameter shaft. When the piston rod retracts inward to its shortest length, the chamfer on the end face of the piston rod's major diameter shaft must not retract into the sealing ring.

[0051] The lubrication channel of the boom mounting hole is connected to the lubrication channel of the limit sleeve by passing through the boom mounting hole, the outer oil groove of the limit sleeve, the oil port of the limit sleeve, and the inner oil groove of the limit sleeve in sequence.

[0052] Furthermore, the quick-change cylinder has a symmetrical structure.

[0053] Thirdly, a loader is provided, the loader being equipped with the quick-change cylinder described in the first aspect and the quick-change device described in the second aspect.

[0054] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: The present invention adopts a method in which the piston rod of the quick-change cylinder is directly connected to the mounting hole of the quick-change tool, eliminating the quick-change pin commonly used in the prior art. The present invention does not require an external quick-change pin at the end of the piston rod of the quick-change cylinder, resulting in a compact quick-change device structure and convenient space arrangement. The direct connection between the piston rod of the quick-change cylinder and the mounting hole of the quick-change tool ensures high coaxiality and good alignment, preventing jamming and making quick-change tool replacement more convenient and faster. The present invention also solves the problem of easy damage and breakage of the piston rod and quick-change pin of the quick-change cylinder. The quick-change cylinder of the present invention uses a limiting sleeve for positioning, which is simple in process and easy to manufacture. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of the present invention;

[0056] Figure 2 This is a schematic diagram of the structure of the limiting sleeve of the present invention;

[0057] Figure 3 This is a schematic diagram of the boom mounting hole structure of the present invention;

[0058] Figure 4 This is a schematic diagram of the quick-change frame connection of the present invention;

[0059] In the diagram, 1 is the quick-change cylinder; 2 is the limit sleeve; 3 is the quick-change frame; 4 is the boom; 5 is the sealing ring; 6 is the quick-change tool mounting plate; 11 is the cylinder barrel; 12 is the bushing; 13 is the piston rod; 14 is the piston; 21 is the large diameter shaft of the limit sleeve; 22 is the small diameter shaft of the limit sleeve; 23 is the inner hole of the limit sleeve; 24 is the inner end face of the large diameter shaft of the limit sleeve; 25 is the outer end face of the large diameter shaft of the limit sleeve; 26 is the end face of the small diameter shaft of the limit sleeve; 27 is the connecting thread of the limit sleeve; 28 is the outer oil groove; 29 is the inner oil groove; 210 is the oil passage hole of the limit sleeve; 211 is the lubrication channel; 212 is the sealing ring mounting groove; 31 is the mounting threaded hole of the quick-change frame; 32 is the outer side of the quick-change frame; 41 is the boom mounting hole; 42 is the inner side of the boom mounting hole; 43 is the outer side of the boom mounting hole; 44 is the lubrication channel of the boom mounting hole; 111 is the large diameter shaft; 25 is the outer end face of the large diameter shaft of the limit sleeve; 26 is the end face of the small diameter shaft of the limit sleeve; 27 is the connecting thread of the limit sleeve; 28 is the outer oil groove; 29 is the inner oil groove; 210 is the oil passage hole of the limit sleeve; 211 is the lubrication channel of the large diameter shaft; 212 is the outer end face of the large diameter shaft of the limit sleeve; 213 is the outer end face of the large diameter shaft of the limit sleeve; 214 is the inner end face of the large diameter shaft of the limit sleeve; 215 is the outer end face of the large diameter shaft of the limit sleeve; 216 is the outer end face 112 is the small cavity oil port; 113 is the cylinder internal thread; 114 is the cylinder external thread; 121 is the bushing large diameter shaft; 122 is the bushing small diameter shaft; 123 is the bushing large diameter hole; 124 is the bushing small diameter hole; 125 is the bushing stepped hole diameter changing limiting surface; 126 is the bushing large diameter shaft end face; 127 is the bushing small diameter shaft end face; 131 is the piston rod large diameter shaft; 132 is the piston rod small diameter shaft; 133 is the piston rod stepped shaft diameter changing limiting surface; 134 is the end face chamfer; 135 is the clamping structure; 1311 is the intermediate diameter shaft; 101 is the large cavity of the oil cylinder; 102 is the small cavity of the oil cylinder. Detailed Implementation

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] Example 1:

[0062] like Figures 1-4 As shown, a quick-change hydraulic cylinder includes: cylinder barrel 11, bushing 12, piston rod 13, and piston 14.

[0063] The piston rod 13 has a stepped shaft structure.

[0064] The outer side of bushing 12 has a stepped shaft structure, and the inner side has a stepped hole structure.

[0065] The piston rod 13 coaxially passes through the bushing 12 and the piston 14 to form the cylinder core assembly. The bushing 12 and the piston rod 13 can move relative to each other in the axial direction. The cylinder core assembly is coaxially inserted into the cylinder barrel 11. The cylinder core assembly and the cylinder barrel 11 can move relative to each other in the axial direction.

[0066] The piston 14 divides the cylinder 11 into the large cylinder chamber 101 and the small cylinder chamber 102.

[0067] A quick-change hydraulic cylinder 1 has a cylinder barrel 11 with a large cavity oil port 111 and a small cavity oil port 112. The large cavity oil port 111 is connected to the large cavity 101 of the hydraulic cylinder, and the small cavity oil port 112 is connected to the small cavity 102 of the hydraulic cylinder.

[0068] The piston 14 moves axially between the large chamber oil port 111 and the small chamber oil port 112.

[0069] A piston rod 13 of a quick-change hydraulic cylinder 1 includes: a piston rod major diameter shaft 131, a piston rod minor diameter shaft 132, and a piston rod stepped shaft diameter-changing limiting surface 133.

[0070] A bushing 12 for a quick-change hydraulic cylinder 1 includes: a bushing major diameter shaft 121, a bushing minor diameter shaft 122, a bushing major diameter hole 123, a bushing minor diameter hole 124, a bushing stepped hole diameter limiting surface 125, a bushing major diameter shaft end face 126, and a bushing minor diameter shaft end face 127; the bushing minor diameter shaft 122 and the bushing minor diameter hole 124 are located at the same end, and the bushing major diameter shaft 121 and the bushing major diameter hole 123 are located at the same end.

[0071] A quick-change hydraulic cylinder 1 has a bushing with a small diameter bore 124 whose radially inner circumferential surface contacts the piston rod with a small diameter shaft 132 whose radially outer circumferential surface contacts the piston rod with a large diameter bore 123 whose radially inner circumferential surface contacts the piston rod with a large diameter shaft 131 whose radially outer circumferential surface contacts the piston rod with a large diameter shaft 131 whose radially outer circumferential surface contacts the piston rod with a large diameter shaft 132 whose radially outer circumferential surface contacts the cylinder 11 whose radially outer circumferential surface contacts the cylinder 11 whose radially outer circumferential surface contacts the cylinder 11 whose radially outer circumferential surface forms a gap with the cylinder 11 whose radially outer circumferential surface is close to the cylinder 11 whose large diameter shaft end face 126 and piston rod large diameter shaft 131 end face are close to the cylinder 11 end face.

[0072] A quick-change hydraulic cylinder 1 has a bushing 12, a bushing stepped bore diameter changing limiting surface 125, and a piston rod stepped shaft diameter changing limiting surface 133 working together to control the axial movement stroke of the piston rod assembly composed of piston 14 and piston rod 13.

[0073] When the piston rod assembly consisting of piston 14 and piston rod 13 moves axially toward bushing 12, when the end face of the small cavity of piston 14 contacts the end face 127 of the small diameter shaft of bushing, the piston rod assembly consisting of piston 14 and piston rod 13 can no longer move axially toward bushing 12.

[0074] When the piston rod assembly consisting of piston 14 and piston rod 13 moves axially away from bushing 12, when the piston rod stepped shaft diameter limiting surface 133 contacts the bushing stepped hole diameter limiting surface 125, the piston rod assembly consisting of piston 14 and piston rod 13 can no longer move axially away from bushing 12.

[0075] In a quick-change hydraulic cylinder 1, there is an area difference between the piston 14 end face and the bushing minor diameter shaft end face 127, with the piston 14 end face area being larger than the bushing minor diameter shaft end face 127 area.

[0076] The piston rod 13 of a quick-change cylinder 1 can also be a split structure, with the minor diameter shaft 132 of the piston rod and the major diameter shaft 131 of the piston rod fixedly assembled and connected as a whole to form the piston rod 13, and the diameter of the major diameter shaft 131 of the piston rod is larger than the diameter of the minor diameter shaft 132 of the piston rod.

[0077] The piston rod 13 is provided with a piston rod end face chamfer 134 to facilitate the alignment and connection of the piston rod major diameter shaft 131 with the quick change tool. The piston rod end face chamfer 134 is located at the end of the piston rod major diameter shaft 131 near the end of the cylinder 11.

[0078] The piston rod 13 is also provided with a clamping structure 135 for assembly and tightening.

[0079] A quick-change hydraulic cylinder 1 has a piston rod major diameter shaft 131 with a middle diameter shaft 1311. The middle diameter shaft 1311 is located near the piston rod stepped shaft diameter changing limiting surface 133. The diameter of the middle diameter shaft 1311 is larger than the diameter of the piston rod minor diameter shaft 132 and smaller than the diameter of the piston rod major diameter shaft 131. The middle diameter shaft 1311 ensures that after the piston rod major diameter shaft 131 and the piston rod minor diameter shaft 132 are assembled as one unit, the piston rod major diameter shaft 131 can still pass through the bushing large inner hole 123 axially.

[0080] The working principle of the quick-change hydraulic cylinder in this invention is as follows:

[0081] After the quick-change device is initially assembled, the position of the bushing 12 inside the quick-change cylinder 1 is uncertain. When the quick-change device is used for the first time, oil needs to be introduced through the large cavity oil port 111 to push the piston rod assembly consisting of piston 14 and piston rod 13 to move outward. Piston 14 contacts the bushing small diameter shaft end face 127 and pushes bushing 12 to move outward along the axial direction until the bushing large diameter shaft end face 126 contacts the limiting sleeve small diameter shaft end face 26. After that, bushing 12 is limited to this position and no longer moves.

[0082] When oil enters through the large chamber port 111 of the quick-change cylinder 1, the oil acts on one side of the large chamber of the piston 14, pushing the piston rod assembly composed of the piston 14 and the piston rod 13 to move outward. The small chamber port 112 of the piston 14 pushes the oil in the small chamber 102 of the cylinder to flow along the gap formed between the radial outer side of the bushing minor diameter shaft 122 and the radial inner side of the cylinder 11 and exit through the small chamber port 112. The piston rod 13 extends. When the piston 14 contacts the end face 127 of the bushing minor diameter shaft and the end face 126 of the bushing major diameter shaft contacts the end face 26 of the limiting sleeve minor diameter shaft, the piston rod 13 extends to its longest length.

[0083] When oil enters through the small cavity port 112 of the quick-change cylinder 1, the oil enters the gap formed between the radially outer side of the bushing minor diameter shaft 122 and the radially inner side of the cylinder 11. When one end face of the piston 14's small cavity is in contact with the end face 127 of the bushing minor diameter shaft, due to the area difference between the end face of the piston 14 and the end face 127 of the bushing minor diameter shaft, and because the area of ​​the piston 14's end face is larger than that of the bushing minor diameter shaft end face 127, the oil acts on the annular area difference formed between the end face of the piston 14 and the end face 127 of the bushing minor diameter shaft. After the oil pushes the one end face of the piston 14's small cavity apart from the end face 127 of the bushing minor diameter shaft to form a gap, the oil acts on the annular surface formed by the piston 14 and the piston rod 13, thereby pushing the piston rod assembly composed of the piston 14 and the piston rod 13. As the piston 14 moves inward, one side of the large chamber pushes the oil in the large chamber 101 of the cylinder to flow and exit through the large chamber oil port 111. When the piston rod stepped shaft diameter limiting surface 133 contacts the bushing stepped hole diameter limiting surface 125, the area of ​​the oil acting on the piston 14 is equal to the area acting on the bushing 12. Both are the area difference formed by the inner diameter of the cylinder barrel 11 and the large diameter shaft 131 of the piston rod. Since the pressure acting on the piston 14 and the bushing 12 is equal, the magnitude of the force acting on the piston 14 and the bushing 12 is equal and the direction is opposite. The cylinder core assembly is in force balance, and the piston rod assembly composed of the piston 14 and the piston rod 13 no longer moves. The piston rod 13 retracts to its shortest length.

[0084] Generally speaking, the part of the piston rod major diameter shaft 131 that mates with the quick-change tool mounting hole requires high hardness, while the requirements for other parts of the piston rod 13 are relatively low. Therefore, to facilitate production and processing, the piston rod 13 can be made into a split structure, with the piston rod 13 divided into the piston rod major diameter shaft 131 and the piston rod minor diameter shaft 132, which are processed independently. After the piston rod major diameter shaft 131 and the piston rod minor diameter shaft 132 are processed independently, they are then assembled into a whole to form the piston rod 13. To prevent deformation of the piston rod major diameter shaft 131 near the piston rod minor diameter shaft 132 due to assembly, which would prevent the piston rod major diameter shaft 131 from passing smoothly through the bushing major diameter hole 123, a middle diameter shaft 1311 is provided at the end of the piston rod major diameter shaft 131 near the piston rod minor diameter shaft 132. The middle diameter shaft 1311 can eliminate the influence of assembly deformation of the piston rod major diameter shaft 131, allowing the piston rod major diameter shaft 131 to still pass smoothly through the bushing major diameter shaft 123 and move freely in the axial direction without jamming.

[0085] The clamping structure 135 provided on the piston rod 13 of the hydraulic cylinder is used when the piston rod 13 is assembled and tightened.

[0086] The quick-change cylinder of the present invention uses a bushing for limiting, eliminating the need for a limiting device in the middle of the quick-change cylinder, resulting in a simple process structure and convenient manufacturing.

[0087] Example 2:

[0088] Based on the quick-change cylinder described in Embodiment 1, this embodiment provides a quick-change device, which is equipped with the quick-change cylinder described in Embodiment 1.

[0089] like Figures 1-4 As shown, a quick-change device includes: a quick-change cylinder 1, a limit sleeve 2, a quick-change frame 3, and a boom 4.

[0090] The quick-change cylinder barrel 11 is fixedly mounted on the quick-change frame 3; the outer side of the limiting sleeve 2 passes coaxially through the boom 4 and the quick-change cylinder 1 in sequence, and the limiting sleeve 2 is fixedly connected to the quick-change cylinder barrel 11. The limiting sleeve 2 and the boom 4 can rotate circumferentially. The quick-change frame 3 and the limiting sleeve 2 work together to restrict the axial movement of the boom 4; the piston rod major diameter shaft 131 passes coaxially through the inner side of the limiting sleeve 2, and the piston rod major diameter shaft 131 and the limiting sleeve 2 can move axially.

[0091] The quick-change cylinder 1 is provided with a structure for connecting with the limit sleeve 2 and the quick-change frame 3; the limit sleeve 2 is provided with a structure for fixedly connecting with the quick-change cylinder 1; the quick-change frame 3 is provided with a structure for fixedly connecting with the quick-change cylinder 1; and the boom 4 is provided with a structure for connecting with the limit sleeve 2.

[0092] The quick-change cylinder barrel 11 has an internal thread 113 on the radially inner side of its end, which is connected to the limiting sleeve 2, and an external thread 114 on the radially outer side of its end, which is connected to the quick-change frame 3.

[0093] The quick-change bracket 3 includes: quick-change bracket mounting threaded hole 31 and quick-change bracket outer surface 32.

[0094] The boom 4 includes: boom mounting hole 41, inner side of boom mounting hole 42, and outer side of boom mounting hole 43.

[0095] The limiting sleeve 2 includes: a limiting sleeve major diameter shaft 21, a limiting sleeve minor diameter shaft 22, a limiting sleeve inner hole 23, a limiting sleeve major diameter shaft inner end face 24, a limiting sleeve major diameter shaft outer end face 25, a limiting sleeve minor diameter shaft end face 26, and a limiting sleeve connecting thread 27.

[0096] The outer side of the limiting sleeve 2 has a stepped shaft structure. The connecting thread 27 of the limiting sleeve is close to the end face 26 of the small diameter shaft of the limiting sleeve. The shaft diameter of the large diameter shaft 21 of the limiting sleeve is larger than the diameter of the boom mounting hole 41.

[0097] The small-diameter shaft 22 of the limiting sleeve passes coaxially through the boom mounting hole 41 and the quick-change cylinder barrel 11 in sequence; the radially outer circumferential surface of the small-diameter shaft 22 of the limiting sleeve contacts the radially inner circumferential surface of the boom mounting hole 41, and the small-diameter shaft 22 of the limiting sleeve is coaxial with the boom mounting hole 41 and can rotate circumferentially; the limiting sleeve 2 is fixedly set on the quick-change cylinder barrel 11 and is fixedly connected to the internal thread 113 at the end of the cylinder barrel through the thread 27 at the end of the small-diameter shaft of the limiting sleeve; the radially inner circumferential surface of the inner hole 23 of the limiting sleeve contacts the radially outer circumferential surface of the major diameter shaft 131 of the piston rod, and the piston rod 13 can move along the shaft 2 of the limiting sleeve.

[0098] The small diameter shaft 22 of the limiting sleeve restricts the axial movement stroke of the piston rod assembly composed of piston 14 and piston rod 13.

[0099] The depth to which the end face 26 of the small diameter shaft of the limiting sleeve extends into the cylinder barrel 11 of the quick-change cylinder limits the outward movement of the quick-change cylinder bushing 12.

[0100] When the piston 14 contacts the bushing minor diameter shaft end face 127 and the bushing major diameter shaft end face 126 contacts the limiting sleeve minor diameter shaft end face 26, the bushing major diameter shaft 121 must not block the small cavity oil port 112 and ensure that the small cavity oil port 112 can form a gap with the outer radial side of the bushing minor diameter shaft 122 and the inner radial side of the cylinder 11, and the quick-change cylinder piston rod 13 extends outward to its maximum length and ensures that the extension length of the outer end face of the piston rod major diameter shaft 131 exceeds the outer end face of the quick-change tool mounting connection plate 6, so that the piston rod 13 can fully mesh with the quick-change tool.

[0101] When the bushing large diameter shaft end face 126 contacts the limiting sleeve small diameter shaft end face 26 and the piston rod stepped shaft diameter changing surface 133 contacts the bushing stepped hole diameter changing limiting surface 125, the piston 14 must not block the large cavity oil port 111. The piston 14 is placed between the large cavity oil port 111 and the small cavity oil port 112 of the oil cylinder. The large cavity oil port 111 and the small cavity oil port 112 act on different sides of the piston 14 respectively, and the piston rod 13 retracts inward to the shortest length and ensures that the outer end face of the piston rod large diameter shaft 131 does not exceed the inner end face of the quick change tool mounting connection plate 6. The piston rod 13 can be completely separated from the quick change tool.

[0102] The large diameter shaft 21 end of the limit sleeve restricts the axial movement of the boom 4 and the quick-change tool.

[0103] The distance between the inner end face 24 of the large diameter shaft of the limiting sleeve and the outer side 32 of the quick change frame is greater than the thickness of the boom mounting hole 41. The inner side 42 of the boom mounting hole is close to the outer side 32 of the quick change frame, and the outer side 43 of the boom mounting hole is close to the inner end face 24 of the large diameter shaft of the limiting sleeve. The outer side 32 of the quick change frame and the inner end face 24 of the large diameter shaft of the limiting sleeve work together to restrict the axial movement of the boom 4.

[0104] The outer end face 25 of the large diameter shaft of the limiting sleeve shall not extend beyond the inner end face of the quick-change tool mounting plate 6, and the outer end face 25 of the large diameter shaft of the limiting sleeve restricts the axial movement of the quick-change tool.

[0105] A quick-change device further includes: a sealing ring 5.

[0106] The limiting sleeve 2 also includes: an outer oil groove 28, an inner oil groove 29, a limiting sleeve oil passage hole 210, a lubrication channel 211, and a sealing ring mounting groove 212; the outer oil groove 28 is provided on the outer wall surface of the limiting sleeve small diameter shaft 22, the inner oil groove 29 is provided on the inner wall surface of the limiting sleeve inner hole 23, the limiting sleeve 2 is radially provided with a limiting sleeve oil passage hole 210, the limiting sleeve oil passage hole 210 connects the limiting sleeve inner oil groove 29 and the outer oil groove 28, the lubrication channel 211 is provided on the inner wall surface of the limiting sleeve inner hole 23, and the lubrication channel 211 is connected to the inner oil groove 29, the sealing ring mounting groove 212 is provided at one end of the limiting sleeve large diameter shaft 21, coaxial with the limiting sleeve inner hole 23, and the diameter of the sealing ring mounting groove 212 is larger than the diameter of the limiting sleeve inner hole 23.

[0107] The boom 4 is provided with a boom mounting hole lubrication channel 44, which is connected to the boom mounting hole 41.

[0108] The sealing ring 5 is coaxially fixed on the sealing ring mounting groove 212 of the limiting sleeve. The radial outer circumferential surface of the sealing ring 5 is connected to the radial inner circumferential surface of the sealing ring mounting groove 212 of the limiting sleeve. The radial inner circumferential surface of the sealing ring 5 is connected to the radial outer circumferential surface of the piston rod major diameter shaft 131. When the piston rod 13 is retracted inward to its shortest length, the end face chamfer 134 of the piston rod major diameter shaft 131 must not be retracted into the sealing ring 5.

[0109] The lubrication channel 44 of the boom mounting hole is connected to the lubrication channel 211 of the limit sleeve through the boom mounting hole 41, the outer oil groove 28 of the limit sleeve, the oil port 210 of the limit sleeve, and the inner oil groove 29 of the limit sleeve in sequence.

[0110] The quick-change hydraulic cylinder 1 can be a symmetrical structure.

[0111] The working principle of the quick-change device in this invention is as follows:

[0112] The engagement and disengagement of the quick-change device and the quick-change tool are achieved by extending and retracting the piston rod 13 of the quick-change cylinder 1.

[0113] When it is necessary to disconnect the quick-change tool connected to the quick-change device, as mentioned above, oil is introduced through the small cavity oil port 112 on the quick-change cylinder 1. When the piston rod assembly composed of piston 14 and piston rod 13 moves to the contact between the piston rod stepped shaft diameter limiting surface 133 and the bushing stepped hole diameter limiting surface 125, the piston rod 13 retracts to its shortest length. At this time, the outer end face of the piston rod large diameter shaft 131 must not exceed the inner end face of the quick-change tool mounting connection plate 6. The piston rod large diameter shaft 131 can be completely disengaged from the quick-change tool. At the same time, the piston rod end face chamfer 134 must not be retracted into the sealing ring 5 to ensure good sealing effect and prevent foreign objects from entering the inner hole 23 of the limiting sleeve.

[0114] When it is necessary to engage the quick-change device with the quick-change tool, as mentioned above, oil is introduced through the large cavity oil port 111 on the quick-change cylinder 1. When the piston rod assembly consisting of piston 14 and piston rod 13 moves to the point where one side of the small cavity of piston 14 contacts the small diameter shaft end face 127 of the bushing, and at the same time the large diameter shaft end face 126 of the bushing contacts the small diameter shaft end face 26 of the limiting sleeve, the piston rod 13 extends to its longest length. At this time, the extension length of the outer end face of the large diameter shaft 131 of the piston rod exceeds the outer end face of the quick-change tool mounting connection plate 6, and the large diameter shaft 131 of the piston rod can fully engage with the quick-change tool.

[0115] The quick-change device enables the quick-change tool to be retracted upwards and tilted downwards by rotating circumferentially between the boom mounting hole 41 and the small diameter shaft 22 of the limit sleeve.

[0116] The inner end face 24 of the large diameter shaft of the limiting sleeve and the outer side 32 of the quick change frame work together to restrict the axial movement of the boom 4, while the outer end face 25 of the large diameter shaft of the limiting sleeve restricts the axial movement of the quick change tool.

[0117] The circumferential rotation between the boom mounting hole 41 and the minor diameter shaft 22 of the limiting sleeve, and the axial movement between the inner hole 23 of the limiting sleeve and the major diameter shaft 131 of the piston rod, require lubrication. Grease is added through the lubrication channel 44 of the boom mounting hole. The grease passes sequentially through the boom mounting hole 41, the outer oil groove 28 of the limiting sleeve, the oil passage 210 of the limiting sleeve, the inner oil groove 29 of the limiting sleeve, and the lubrication channel 211, thus adding grease to the lubrication gaps between the minor diameter shaft 22 of the limiting sleeve and the boom mounting hole 41, and between the major diameter shaft 131 of the piston rod and the inner hole 23 of the limiting sleeve, achieving the lubrication function.

[0118] The quick-change device of this invention connects directly to the quick-change tool mounting hole via the large-diameter shaft of the quick-change cylinder piston rod, eliminating the need for an external quick-change pin at the end of the piston rod. This results in a compact structure and saves installation space. Furthermore, the piston rod and mounting hole of this invention offer good alignment, preventing jamming during tool replacement and making tool changes more convenient. This invention also solves the problem of breakage and damage at the connection between the piston rod and the quick-change pin, improving the reliability of the quick-change device.

[0119] Example 3:

[0120] Based on the quick-change cylinder described in Embodiment 1 and the quick-change device described in Embodiment 2, this embodiment provides an engineering machinery, which is equipped with the quick-change cylinder described in Embodiment 1 or the quick-change device described in Embodiment 2.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles and spirit of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A quick-change hydraulic cylinder, characterized in that: The quick-change cylinder (1) includes a cylinder barrel (11), a bushing (12), a piston rod (13), and a piston (14). The piston rod (13) has a stepped shaft structure; The bushing (12) has a stepped shaft structure on the outside and a stepped hole structure on the inside; The piston rod (13) passes coaxially through the bushing (12) and the piston (14) to form the cylinder core assembly. The bushing (12) and the piston rod (13) can move relative to each other in the axial direction. The cylinder core assembly is coaxially inserted into the cylinder (11). The cylinder core assembly and the cylinder (11) can move relative to each other in the axial direction. The piston (14) divides the cylinder (11) into the large cylinder chamber (101) and the small cylinder chamber (102).

2. The quick-change cylinder, quick-change device, and engineering machinery according to claim 1, characterized in that: The cylinder (11) is provided with a large cavity oil port (111) connected to the large cavity (101) of the oil cylinder and a small cavity oil port (112) connected to the small cavity (102) of the oil cylinder. The piston (14) moves axially between the large cavity oil port (111) and the small cavity oil port (112). The bushing (12) includes a bushing major diameter shaft (121), a bushing minor diameter shaft (122), a bushing major diameter hole (123), a bushing minor diameter hole (124), a bushing stepped hole diameter limiting surface (125), a bushing major diameter shaft end face (126), and a bushing minor diameter shaft end face (127); the bushing minor diameter shaft (122) and the bushing minor diameter hole (124) are located at the same end, and the bushing major diameter shaft (121) and the bushing major diameter hole (123) are located at the same end; The piston rod (13) includes a piston rod major diameter shaft (131), a piston rod minor diameter shaft (132), and a piston rod stepped shaft diameter limiting surface (133).

3. The quick-change cylinder, quick-change device, and engineering machinery according to claim 2, characterized in that: The inner radial surface of the bushing small diameter hole (124) contacts the outer radial surface of the piston rod small diameter shaft (132), and the inner radial surface of the bushing large diameter hole (123) contacts the outer radial surface of the piston rod large diameter shaft (131). The piston (14) and the piston rod (13) are fixedly connected to form a piston rod assembly. The piston (14) is located at the end of the piston rod small diameter shaft (132). The outer radial surface of the piston (14) contacts the inner radial surface of the cylinder (11), and the outer radial surface of the bushing large diameter shaft (121) contacts the inner radial surface of the cylinder (11). A gap is formed between the outer radial surface of the bushing small diameter shaft (122) and the inner radial surface of the cylinder (11). The end face (126) of the bushing large diameter shaft and the end face (131) of the piston rod are close to the end of the cylinder (11).

4. The quick-change hydraulic cylinder, quick-change device, and engineering machinery according to claim 2, characterized in that: The bushing (12), bushing stepped hole diameter limiting surface (125), and piston rod stepped shaft diameter limiting surface (133) work together to control the axial movement stroke of the piston rod assembly composed of piston (14) and piston rod (13). When the piston rod assembly consisting of the piston (14) and the piston rod (13) moves axially closer to the bushing (12), when the end face of the small cavity of the piston (14) contacts the end face (127) of the small diameter shaft of the bushing, the piston rod assembly cannot move closer to the bushing (12) in the axial direction. When the piston rod assembly consisting of the piston (14) and the piston rod (13) moves away from the bushing (12) in the axial direction, when the piston rod stepped shaft diameter limiting surface (133) contacts the bushing stepped hole diameter limiting surface (125), the piston rod assembly cannot move away from the bushing (12) in the axial direction. There is an area difference between the end face of the piston (14) and the end face (127) of the bushing minor diameter shaft, and the area of ​​the end face of the piston (14) is greater than the area of ​​the end face (127) of the bushing minor diameter shaft.

5. The quick-change cylinder, quick-change device, and engineering machinery according to claim 2, characterized in that: The piston rod (13) is a split structure. The piston rod major diameter shaft (131) and piston rod minor diameter shaft (132) are fixedly assembled and connected to form a piston rod (13). The diameter of the piston rod major diameter shaft (131) is larger than the diameter of the piston rod minor diameter shaft (132). The piston rod (13) is provided with an end face chamfer (134) to facilitate the alignment and connection of the piston rod major diameter shaft (131) with the quick change tool. The end face chamfer (134) is located at the end of the piston rod major diameter shaft (131) near the end of the cylinder (11). The piston rod (13) is provided with a clamping structure (135) for assembly and tightening. The piston rod major diameter shaft (131) is provided with a middle diameter shaft (1311). The middle diameter shaft (1311) is located near the piston rod stepped shaft diameter limiting surface (133). The diameter of the middle diameter shaft (1311) is larger than the diameter of the piston rod minor diameter shaft (132) and smaller than the diameter of the piston rod major diameter shaft (131). The middle diameter shaft (1311) ensures that after the piston rod major diameter shaft (131) and the piston rod minor diameter shaft (132) are assembled into one piece, the piston rod major diameter shaft (131) can still pass through the bushing major diameter hole (123) axially.

6. A quick-change device, characterized in that: The system includes a quick-change cylinder (1), a limiting sleeve (2), a quick-change frame (3), and a boom (4) as described in any one of claims 1-5; the cylinder barrel (11) of the quick-change cylinder (1) is fixedly mounted on the quick-change frame (3), and the outer side of the limiting sleeve (2) passes coaxially through the boom (4) and the quick-change cylinder (1) in sequence. The limiting sleeve (2) and the cylinder barrel (11) are fixedly connected together, and the limiting sleeve (2) and the boom (4) can rotate circumferentially. The quick-change frame (3) and the limiting sleeve (2) work together to restrict the axial movement of the boom (4); the piston rod major diameter shaft (131) passes coaxially through the inner side of the limiting sleeve (2), and the piston rod major diameter shafts (131) can move axially between each other. The quick-change cylinder (1) is provided with a structure for connecting with the limiting sleeve (2) and the quick-change frame (3); The limiting sleeve (2) is provided with a structure for fixed connection with the quick-change oil cylinder (1); The quick-change frame (3) is provided with a structure for fixed connection with the quick-change cylinder (1); The boom (4) is provided with a structure for connecting with the limiting sleeve (2).

7. The quick-change device according to claim 6, characterized in that: The cylinder (11) is provided with an internal thread (113) on the radially inner side of the end of the cylinder (11) for connection with the limiting sleeve (2), and an external thread (114) on the radially outer side of the end of the cylinder (11) for connection with the quick change frame (3). The quick-change bracket (3) is provided with a quick-change bracket mounting threaded hole (31) and a quick-change bracket outer side (32); The boom (4) is provided with a boom mounting hole (41), an inner side surface (42) of the boom mounting hole, and an outer side surface (43) of the boom mounting hole. The limiting sleeve (2) includes a limiting sleeve major diameter shaft (21), a limiting sleeve minor diameter shaft (22), a limiting sleeve inner hole (23), a limiting sleeve major diameter shaft inner end face (24), a limiting sleeve major diameter shaft outer end face (25), a limiting sleeve minor diameter shaft end face (26), and a limiting sleeve connecting thread (27). The outer side of the limiting sleeve (2) is a stepped shaft structure. The connecting thread (27) of the limiting sleeve is close to the end face (26) of the small diameter shaft of the limiting sleeve. The shaft diameter of the large diameter shaft (21) of the limiting sleeve is larger than the diameter of the boom mounting hole (41). The small diameter shaft (22) of the limiting sleeve passes coaxially through the boom mounting hole (41) and the cylinder (11) in sequence. The radial outer circumferential surface of the small diameter shaft (22) of the limiting sleeve contacts the radial inner circumferential surface of the boom mounting hole (41). The small diameter shaft (22) of the limiting sleeve is coaxial with the boom mounting hole (41) and can rotate circumferentially. The limiting sleeve (2) is fixedly set on the cylinder (11) and is fixedly connected to the cylinder internal thread (113) through the limiting sleeve connecting thread (27). The radial inner circumferential surface of the inner hole (23) of the limiting sleeve contacts the radial outer circumferential surface of the piston rod large diameter shaft (131). The piston rod (13) can move axially along the limiting sleeve (2).

8. The quick-change device according to claim 7, characterized in that: The limiting sleeve small diameter shaft (22) end restricts the axial movement stroke of the piston rod assembly composed of piston (14) and piston rod (13); the depth of the limiting sleeve small diameter shaft end face (26) extending into the cylinder (11) restricts the extreme position of the bushing (12) moving outward. When the piston (14) contacts the end face (127) of the bushing small diameter shaft and the end face (126) of the bushing large diameter shaft contacts the end face (26) of the limit sleeve small diameter shaft, the bushing large diameter shaft (121) shall not cover the small cavity oil port (112) and ensure that the small cavity oil port (112) can form a gap with the outer side of the bushing small diameter shaft (122) and the inner side of the cylinder (11) to form a connection, and the piston rod (13) extends outward to the longest length and ensures that the extension length of the outer end face of the piston rod large diameter shaft (131) exceeds the outer end face of the quick change tool mounting connection plate (6), and the piston rod (13) fully meshes with the quick change tool; When the bushing large diameter shaft end face (126) contacts the limiting sleeve small diameter shaft end face (26) and the piston rod stepped shaft diameter limiting surface (133) contacts the bushing stepped hole diameter limiting surface (125), the piston (14) must not cover the large cavity oil port (111). The piston (14) is placed between the large cavity oil port (111) and the small cavity oil port (112). The large cavity oil port (111) and the small cavity oil port (112) act on different sides of the piston (14) respectively. The piston rod (13) retracts inward to the shortest length and ensures that the outer end face of the piston rod large diameter shaft (131) does not exceed the inner end face of the quick change tool mounting connection plate (6). The piston rod (13) is completely separated from the quick change tool.

9. The quick-change device according to claim 7, characterized in that: The large diameter shaft (21) of the limiting sleeve restricts the axial movement of the boom (4) and the quick-change tool; the distance between the inner end face (24) of the large diameter shaft of the limiting sleeve and the outer side face (32) of the quick-change frame is greater than the thickness of the boom mounting hole (41), the inner side face (42) of the boom mounting hole is close to the outer side face (32) of the quick-change frame, the outer side face (43) of the boom mounting hole is close to the inner end face (24) of the large diameter shaft of the limiting sleeve, and the outer side face (32) of the quick-change frame and the inner end face (24) of the large diameter shaft of the limiting sleeve work together to restrict the axial movement of the boom (4); The outer end face (25) of the large diameter shaft of the limiting sleeve shall not extend beyond the inner end face of the quick-change tool mounting plate (6), and the outer end face (25) of the large diameter shaft of the limiting sleeve restricts the axial movement of the quick-change tool.

10. The quick-change device according to claim 6, characterized in that: It also includes a sealing ring (5), and the limiting sleeve (2) further includes an outer oil groove (28), an inner oil groove (29), a limiting sleeve oil passage hole (210), a lubrication channel (211), and a sealing ring mounting groove (212); the outer oil groove (28) is provided on the outer wall surface of the small diameter shaft (22) of the limiting sleeve, and the inner oil groove (29) is provided on the inner wall surface of the inner hole (23) of the limiting sleeve; the limiting sleeve (2) is radially provided with a limiting sleeve oil passage hole (210). The oil passage (210) of the limiting sleeve connects the outer oil groove (28) and the inner oil groove (29); the lubrication channel (211) is set on the inner wall of the inner hole (23) of the limiting sleeve, and the lubrication channel (211) is connected to the inner oil groove (29); the sealing ring mounting groove (212) is set at one end of the large diameter shaft (21) of the limiting sleeve, coaxial with the inner hole (23) of the limiting sleeve, and the diameter of the sealing ring mounting groove (212) is larger than the diameter of the inner hole (23) of the limiting sleeve; The boom (4) is provided with a boom mounting hole lubrication channel (44), which is connected to the boom mounting hole (41); the boom mounting hole lubrication channel (44) is connected to the lubrication channel (211) through the boom mounting hole (41), the outer oil groove (28), the oil passage hole of the limiting sleeve (210), and the inner oil groove (29) in sequence; The sealing ring (5) is coaxially fixed on the sealing ring mounting groove (212). The outer radial circumferential surface of the sealing ring (5) is connected to the inner radial circumferential surface of the sealing ring mounting groove (212). The inner radial circumferential surface of the sealing ring (5) is connected to the outer radial circumferential surface of the piston rod major diameter shaft (131). When the piston rod (13) is retracted inward to its shortest length, the end face chamfer (134) of the piston rod major diameter shaft (131) must not be retracted into the sealing ring (5).

11. An engineering machinery, characterized in that: Use the quick-change cylinder (1) according to any one of claims 1-5 or the quick-change device according to any one of claims 6-10.

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