An extreme position locking hydraulic cylinder and an engineering machine

Abstract

This invention discloses a hydraulic cylinder for locking at an extreme position and related engineering machinery, belonging to the field of engineering machinery technology. The locking hydraulic cylinder includes a cylinder barrel, a piston with a rod, and a tail cover; it also includes a first locking part, a second locking part, a third locking part, and a fourth locking part arranged coaxially and nested; it also includes a steel ball retainer disposed at the head of the third locking part and fixedly connected to the first locking part, the inner and outer walls of the steel ball retainer being flush with the inner and outer walls of the third locking part, and a plurality of first steel balls disposed on its periphery; the second locking part and the fourth locking part respectively have grooves corresponding to the first steel balls; it also includes a locking mechanism, the locking mechanism including a plurality of radial holes disposed on the periphery of the second locking part, and radial grooves disposed on the first and third locking parts opposite to the radial holes, with a plurality of second steel balls disposed in the radial holes. This invention, through the steel ball locking mechanism, can lock at the extreme position at the end and maintain it for a long time; at the same time, the overall structure is simple, with a long service life and low cost.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, and in particular to a limit position locking hydraulic cylinder and engineering machinery. Background Technology

[0002] Boom-type machinery (such as aerial work platforms, cranes, and concrete pump trucks) needs to maintain stability under complex working conditions such as high-altitude luffing, load support, and emergency response. National standards such as GB7965.12 "Aerial Fire Trucks" impose strict technical requirements on boom locking performance, retraction control, and fault protection. As the requirements for boom height, load-bearing capacity, and adaptability to working conditions continue to increase, the highly reliable locking function of hydraulic cylinders has become a key technical element in ensuring the safety of boom-type machinery.

[0003] Currently, locking of the hydraulic cylinder piston rod is achieved using an external hydraulic control unit. This method requires a set of matching hydraulic operating systems, making the mechanism relatively complex. Another type is the built-in locking mechanism, which locks the piston rod by sealing the oil port and maintaining the oil pressure inside the cylinder. This method still requires external operation to activate the locking mechanism, and a disengagement operation must be performed before operating the hydraulic cylinder. Furthermore, because oil pressure needs to be maintained, it is necessary to replenish the oil in a timely manner during prolonged locking to prevent malfunctions or even safety accidents. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a limit position locking hydraulic cylinder and engineering machinery, solving the technical problems of complex structure and poor locking stability of the prior art.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a limit position locking hydraulic cylinder, comprising a cylinder barrel, a rod piston movably disposed on the inner wall of the cylinder barrel, and a tail cap disposed at the tail end of the cylinder barrel; the locking hydraulic cylinder further comprises: The first locking part is fixed to the inner wall of the cylinder. The second locking part is movably disposed on the inner wall of the first locking part, and its tail is connected to the tail cap through the first elastic member. A guide groove is provided on the inner wall near the tail cap. The third locking part is movably disposed on the inner wall of the second locking part, and its tail is connected to the tail cap through the second elastic element. The outer wall is provided with a guide block that cooperates with the guide groove. The side wall of the third locking part is also provided with a guide hole in the axial direction. A radially arranged limiting rod is provided in the guide hole, and the end of the limiting rod is fixed to the second locking part. The fourth locking part is movably disposed on the inner wall of the third locking part, and its tail is fixed to the tail of the rod piston, and its head is chamfered. A steel ball retainer is disposed at the head of the third locking part and fixedly connected to the first locking part. The inner and outer walls of the steel ball retainer are flush with the inner and outer walls of the third locking part, respectively, and a plurality of first steel balls are disposed on its periphery. The second locking part and the fourth locking part are respectively provided with a first groove and a second groove corresponding to the first steel balls. The locking mechanism includes a plurality of radial holes opened around the second locking part, a first radial groove and a second radial groove opened on the first locking part and the third locking part opposite to the radial holes, a third elastic element being provided in the first radial groove, a chamfer being opened on the side of the second radial groove near the rod piston, and a plurality of second steel balls being provided in the radial holes.

[0006] Optionally, the piston with rod includes a piston body and a piston rod disposed on the axis of the piston body, and the fourth locking part is fixed to the tail of the piston body or the tail of the piston rod.

[0007] Optionally, the steel ball holder includes a cylindrical body with a plurality of cylindrical grooves evenly distributed around its periphery. The bottom of each cylindrical groove has an inwardly converging protrusion, and the first steel ball is placed in the cylindrical groove and supported by the protrusion.

[0008] Optionally, the guide holes are symmetrically arranged on the side wall of the third locking part, and the limiting rod passes through the two guide holes radially and is connected to the second locking part.

[0009] Optionally, the cylinder and the tail cover are connected by threads.

[0010] Optionally, in the unlocked state, the first groove is located directly above the first steel ball, hydraulic oil enters the rod chamber, the rod piston retracts, pushing the fourth locking part into the steel ball holder, and the chamfer at the head of the fourth locking part presses the first steel ball upward into the first groove; When the first steel ball is tangent to the outer wall of the fourth locking part, the head of the fourth locking part abuts against the limiting rod. As the fourth locking part advances, it pushes the second locking part to move through the limiting rod. After the first steel ball moves along the outer wall of the fourth locking part, it falls into the second groove. The inner wall of the second locking part moves above the first steel ball, preventing the first steel ball from leaving the second groove. Locking is completed when both the inner wall of the second locking part and the inner wall of the second groove abut against the first steel ball.

[0011] Optionally, in the locked state, the first radial groove, the radial hole, and the second radial groove are collinear, the third elastic member presses against the plurality of second steel balls, the center plane of the second steel ball closest to the third elastic member is flush with the outer wall of the second locking part, the second locking part is locked, and the locked state is maintained.

[0012] Optionally, in the locked state, hydraulic oil enters between the third locking part and the fourth locking part, the fourth locking part is locked and cannot extend, and the third locking part moves in the opposite direction to the fourth locking part under the action of oil pressure. The second steel ball farthest from the third elastic member climbs along the chamfer of the second radial groove. When it climbs to the point of being tangent to the outer wall of the third locking part, the second steel ball closest to the third elastic member is tangent to the outer wall of the second locking part, and the second locking part is unlocked.

[0013] Optionally, when the second locking part is unlocked, the third locking part continues to move, the guide block moves within the guide groove and ultimately pushes the second locking part to move, the inner wall of the second locking part disengages from the first steel ball, the fourth locking part is released from locking, and the first steel ball, under the action of the fourth locking part, climbs up from the second groove and descends along the chamfered corner of the head of the fourth locking part, hydraulic oil enters the rod chamber, the oil pressure between the third locking part and the fourth locking part decreases, and the second locking part and the third locking part are reset under the action of the first elastic member and the second elastic member.

[0014] Secondly, the present invention provides an engineering machine, including the limit position locking hydraulic cylinder as described above.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: This invention provides a hydraulic cylinder for extreme position locking and related engineering machinery. The hydraulic cylinder contains a steel ball locking mechanism, which can lock at the ultimate extreme position and maintain that position for an extended period. It adopts a modular layout, resulting in a compact and reliable overall structure. By removing the tail cap, each locking component and steel ball retainer can be individually removed, facilitating installation, production, use, and maintenance. The stiffness of each elastic element can be adjusted according to the hydraulic system conditions, thereby adjusting the locking opening pressure; the size and number of steel balls can also be adjusted to ensure locking force for different specifications and models. The overall structure is simple, with good operational stability, easy processing, long service life, and low cost, making it easy to promote and apply. Attached Figure Description

[0016] Figure 1 This is an overall structural diagram of the limit position locking hydraulic cylinder provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of each locking component provided in the embodiments of the present invention; Figure 3This is a schematic diagram of the steel ball cage provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the locking process provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the unlocking process provided in an embodiment of the present invention; The diagram is marked as follows: 1. Cylinder; 11. Tail cover; 2. Piston with rod; 21. Piston body; 22. Piston rod; 3. First locking part; 4. Second locking part; 41. First elastic element; 42. Guide groove; 43. First groove; 5. Third locking part; 51. Second elastic element; 52. Guide block; 53. Guide hole; 54. Limiting rod; 6. Fourth locking part; 61. Second groove; 7. Steel ball cage; 71. Cylinder; 72. Cylindrical groove; 73. Protrusion; 74. First steel ball; 8. Locking mechanism; 81. Radial hole; 82. First radial groove; 83. Second radial groove; 84. Third elastic element; 85. Second steel ball. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] Example 1

[0021] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a limit position locking hydraulic cylinder, including a cylinder barrel 1, a rod piston 2 movably disposed on the inner wall of the cylinder barrel 1, and a tail cover 11 disposed at the tail of the cylinder barrel 1. The cylinder barrel 1 and the tail cover 11 are connected by threads, which provides a stable connection and facilitates disassembly, maintenance and repair. The rod piston 2 includes a piston body 21 and a piston rod 22 disposed on the axis of the piston body 21.

[0022] Based on this, the locking hydraulic cylinder also includes a first locking part 3, a second locking part 4, a third locking part 5, a fourth locking part 6 and a steel ball retainer 7, which are coaxially arranged with the cylinder barrel 1. The first locking part 3 is fixed to the inner wall of the cylinder barrel 1. The inner wall of the first locking part 3 is stepped and can be divided into a first step, a second step and a third step from the inside to the outside in the radial direction.

[0023] The second locking part 4 is movably disposed on the inner wall of the first locking part 3, and its tail is connected to the tail cover 11 through the first elastic member 41. A guide groove 42 is provided on the inner wall near the tail cover 11. In order to facilitate the fixing of the first elastic member 41, the second locking part 4 can be configured as an L-shape, with the inner wall of the long side slidingly connected to the second step and the end of the short side slidingly connected to the third step. The first elastic member 41 is fixed to the outer wall of the short side by fasteners.

[0024] The third locking part 5 is movably disposed on the inner wall of the second locking part 4, and its tail is connected to the tail cap 11 through the second elastic member 51. A guide block 52 that mates with the guide groove 42 is provided on the outer wall. A guide hole 53 along the axial direction is also provided on the side wall of the third locking part 5. A radially arranged limiting rod 54 is disposed within the guide hole 53, and the end of the limiting rod 54 is fixed to the second locking part 4. In this embodiment, the guide holes 53 are symmetrically arranged on the side wall of the third locking part 5, and the limiting rod 54 passes radially through the two guide holes 53 and connects to the second locking part 4. This symmetrical structure ensures the stability of the movement of the limiting rod 54 within the guide holes 53.

[0025] The fourth locking part 6 is movably disposed on the inner wall of the third locking part 5, and its tail is fixed to the tail of the rod piston 2, while its head has a chamfer. The fourth locking part 6 can be fixed to the tail of the piston body 21 or to the tail of the piston rod 22. In this embodiment, the fourth locking part 6 is threaded onto the piston rod 22, and an anti-loosening screw is installed for axial limiting to ensure the stability of the connection.

[0026] like Figure 3 As shown, the steel ball retainer 7 includes a cylindrical body 71, with multiple cylindrical grooves 72 evenly distributed around its periphery. The bottom of each cylindrical groove 72 has an inwardly converging protrusion 73. The first steel ball 74 is placed within the cylindrical groove 72 and supported by the protrusion 73. The steel ball retainer 7 is located at the head of the third locking part 5 and is fixedly connected to the first locking part 3. The inner and outer walls of the steel ball retainer 7 are flush with the inner and outer walls of the third locking part 5, respectively. The second locking part 4 and the fourth locking part 6 have a first groove 43 and a second groove 61 corresponding to the first steel ball 74, respectively.

[0027] The locking mechanism 8 includes multiple radial holes 81 opened around the second locking part 4, a first radial groove 82 and a second radial groove 83 opened on the first locking part 3 and the third locking part 5 opposite to the radial holes 81. A third elastic element 84 is provided in the first radial groove 82, and a chamfer is opened on the side of the second radial groove 83 near the rod piston 2. Multiple second steel balls 85 are provided in the radial holes 81.

[0028] The present invention provides a working process for a limit position locking hydraulic cylinder as follows: like Figure 4 As shown, in the unlocked state, the first groove 43 is located directly above the first steel ball 74. Hydraulic oil enters the rod chamber, the rod piston 2 retracts, and pushes the fourth locking part 6 into the steel ball holder 7. The chamfer at the head of the fourth locking part 6 squeezes the first steel ball 74 upward into the first groove 43.

[0029] When the first steel ball 74 is tangent to the outer wall of the fourth locking part 6, the head of the fourth locking part 6 abuts against the limiting rod 54. While the fourth locking part 6 is advancing, it pushes the second locking part 4 to move through the limiting rod 54. After the first steel ball 74 moves along the outer wall of the fourth locking part 6, it falls into the second groove 61. The inner wall of the second locking part 4 moves above the first steel ball 74, preventing the first steel ball 74 from leaving the second groove 61. When the inner wall of the second locking part 4 and the inner wall of the second groove 61 both abut against the first steel ball 74, locking is completed.

[0030] In the locked state, the first radial groove 82, the radial hole 81, and the second radial groove 83 are collinear, the third elastic member 84 presses against the multiple second steel balls 85, and the center plane of the second steel ball 85 closest to the third elastic member 84 is flush with the outer wall of the second locking part 4, the second locking part 4 is locked, and the locked state is maintained.

[0031] like Figure 5 As shown, in the locked state, hydraulic oil enters between the third locking part 5 and the fourth locking part 6. The fourth locking part 6 is locked and cannot extend. Under the action of oil pressure, the third locking part 5 moves in the opposite direction to the fourth locking part 6. The second steel ball 85, which is farthest from the third elastic member 84, climbs along the chamfer of the second radial groove 83. When it climbs to the point where it is tangent to the outer wall of the third locking part 5, the second steel ball 85, which is closest to the third elastic member 84, is tangent to the outer wall of the second locking part 4, and the second locking part 4 is unlocked.

[0032] With the second locking part 4 unlocked, the third locking part 5 continues to move, the guide block 52 moves within the guide groove 42 and ultimately pushes the second locking part 4 to move, the inner wall of the second locking part 4 disengages from the first steel ball 74, the fourth locking part 6 is released from locking, and the first steel ball 74, under the action of the fourth locking part 6, climbs up from the second groove 61 and descends along the chamfered corner of the head of the fourth locking part 6, hydraulic oil enters the rod chamber, the oil pressure between the third locking part 5 and the fourth locking part 6 decreases, and the second locking part 4 and the third locking part 5 are reset under the action of the first elastic member 41 and the second elastic member 51.

[0033] Among them, the first elastic element 41, the second elastic element 51, and the third elastic element 84 are all reset springs.

[0034] Example 2

[0035] Based on the limit position locking hydraulic cylinder provided in Embodiment 1, this embodiment of the invention provides an engineering machine, including the limit position locking hydraulic cylinder as described above.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles 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 limit position locking hydraulic cylinder, comprising a cylinder barrel, a rod piston movably disposed on the inner wall of the cylinder barrel, and a tail cap disposed at the tail end of the cylinder barrel; characterized in that, The locking hydraulic cylinder also includes: The first locking part is fixed to the inner wall of the cylinder. The second locking part is movably disposed on the inner wall of the first locking part, and its tail is connected to the tail cap through the first elastic member. A guide groove is provided on the inner wall near the tail cap. The third locking part is movably disposed on the inner wall of the second locking part, and its tail is connected to the tail cap through the second elastic element. The outer wall is provided with a guide block that cooperates with the guide groove. The side wall of the third locking part is also provided with a guide hole in the axial direction. A radially arranged limiting rod is provided in the guide hole, and the end of the limiting rod is fixed to the second locking part. The fourth locking part is movably disposed on the inner wall of the third locking part, and its tail is fixed to the tail of the rod piston, and its head is chamfered. A steel ball retainer is disposed at the head of the third locking part and fixedly connected to the first locking part. The inner and outer walls of the steel ball retainer are flush with the inner and outer walls of the third locking part, respectively, and a plurality of first steel balls are disposed on its periphery. The second locking part and the fourth locking part are respectively provided with a first groove and a second groove corresponding to the first steel balls. The locking mechanism includes a plurality of radial holes opened around the second locking part, a first radial groove and a second radial groove opened on the first locking part and the third locking part opposite to the radial holes, a third elastic element being provided in the first radial groove, a chamfer being opened on the side of the second radial groove near the rod piston, and a plurality of second steel balls being provided in the radial holes.

2. The limit position locking hydraulic cylinder according to claim 1, characterized in that, The piston with rod includes a piston body and a piston rod disposed on the axis of the piston body, and the fourth locking part is fixed to the tail of the piston body or the tail of the piston rod.

3. The limit position locking hydraulic cylinder according to claim 1, characterized in that, The steel ball retainer includes a cylindrical body with multiple cylindrical grooves evenly distributed around its periphery. The bottom of each cylindrical groove has an inwardly converging protrusion. The first steel ball is placed in the cylindrical groove and supported by the protrusion.

4. The limit position locking hydraulic cylinder according to claim 1, characterized in that, The guide holes are symmetrically arranged on the side wall of the third locking part, and the limiting rod passes through the two guide holes radially and is connected to the second locking part.

5. The limit position locking hydraulic cylinder according to claim 1, characterized in that, The cylinder and the tail cover are connected by threads.

6. The limit position locking hydraulic cylinder according to claim 1, characterized in that, In the unlocked state, the first groove is located directly above the first steel ball. Hydraulic oil enters the rod chamber, the rod piston retracts, and pushes the fourth locking part into the steel ball holder. The chamfer at the head of the fourth locking part squeezes the first steel ball upward into the first groove. When the first steel ball is tangent to the outer wall of the fourth locking part, the head of the fourth locking part abuts against the limiting rod. As the fourth locking part advances, it pushes the second locking part to move through the limiting rod. After the first steel ball moves along the outer wall of the fourth locking part, it falls into the second groove. The inner wall of the second locking part moves above the first steel ball, preventing the first steel ball from leaving the second groove. Locking is completed when both the inner wall of the second locking part and the inner wall of the second groove abut against the first steel ball.

7. The limit position locking hydraulic cylinder according to claim 6, characterized in that, In the locked state, the first radial groove, the radial hole, and the second radial groove are collinear. The third elastic member presses against the plurality of second steel balls. The center plane of the second steel ball closest to the third elastic member is flush with the outer wall of the second locking part. The second locking part is locked, maintaining the locked state.

8. The limit position locking hydraulic cylinder according to claim 7, characterized in that, In the locked state, hydraulic oil enters between the third locking part and the fourth locking part, the fourth locking part is locked and cannot extend, and the third locking part moves in the opposite direction to the fourth locking part under the action of oil pressure. The second steel ball farthest from the third elastic member climbs up along the chamfer of the second radial groove. When it climbs to the point where it is tangent to the outer wall of the third locking part, the second steel ball closest to the third elastic member is tangent to the outer wall of the second locking part, and the second locking part is unlocked.

9. The limit position locking hydraulic cylinder according to claim 8, characterized in that, With the second locking part unlocked, the third locking part continues to move, the guide block moves within the guide groove and ultimately pushes the second locking part to move, the inner wall of the second locking part disengages from the first steel ball, the fourth locking part is released from locking, and the first steel ball, under the action of the fourth locking part, climbs up from the second groove and descends along the chamfered corner of the head of the fourth locking part, hydraulic oil enters the rod chamber, the oil pressure between the third locking part and the fourth locking part decreases, and the second locking part and the third locking part are reset under the action of the first elastic member and the second elastic member.

10. An engineering machinery, characterized in that, Includes the limit position locking hydraulic cylinder as described in any one of claims 1-9.

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