Hollow piston rod

Abstract

The utility model discloses a hollow piston rod which comprises an oil cylinder and a piston rod, the piston rod comprises a piston rod body and a piston rod head, and the piston rod head is connected to one end of the piston rod body. The piston rod body is provided with a connecting rod at the other end of the piston rod head, the piston rod body is hollow in the axial direction, and two oil pipes are arranged to be communicated with the piston rod head and the connecting rod. The piston rod is subjected to hollow treatment, a traditional oil way is replaced by welding of the two oil pipes at the hollow portion, and the novel piston rod formed by welding of the oil inlet structure, the oil passing structure and the oil outlet structure is formed. Meanwhile, due to the fact that the oil way is arranged in the piston rod, the design of an oil nozzle can be omitted when the oil cylinder is machined, the machining technology of the oil cylinder is simplified, and the space utilization rate is increased.

Description

Technical Field

[0001] This utility model relates to the field of engineering machinery, and in particular to a hollow piston rod. Background Technology

[0002] A piston rod is a device that enables the piston to perform work. It is generally used in the operation of hydraulic cylinders to drive the generation of power. The main function of the piston rod is to convert the reciprocating motion of the piston into linear motion or vice versa, thereby transmitting the force acting on the piston and driving the piston to move.

[0003] Chinese Patent Publication No. CN218670608U discloses a piston rod, a hydraulic cylinder, and a working machine, having a first end and a second end opposite to each other. The second end is used to fix the piston. A deep hole is drilled inside the piston rod to form a first oil delivery channel and a second oil delivery channel. The first oil inlet of the first oil delivery channel and the second oil inlet of the second oil delivery channel are both located at the first end, and the first oil outlet of the first oil delivery channel is located on the side of the piston away from the first end, while the second oil outlet of the second oil delivery channel is located on the side of the piston facing the first end. In this invention, the piston rod experiences significant inertial force during high-frequency movement, increasing the risk of component loosening and potentially causing structural cracks. Summary of the Invention

[0004] This utility model aims to overcome the complex welding and processing problems of hydraulic cylinder ports. It provides a hollow piston rod that not only meets normal production requirements but also simplifies the hydraulic cylinder welding process and overcomes the limitations of the hydraulic cylinder's installation position in the oil inlet space. It saves time and effort, has high performance and cost-effectiveness, and brings convenience to production operations.

[0005] A hollow piston rod includes a hydraulic cylinder and a piston rod. The piston rod includes a piston rod body and a piston rod head. The piston rod head is connected to one end of the piston rod body. The piston rod body has a connecting rod at the other end of the piston rod head. The piston rod body is hollow inside along the axial direction and has two oil pipes connecting the piston rod head and the connecting rod.

[0006] Furthermore, the two oil pipes are respectively labeled as the first oil pipe and the second oil pipe, and the first oil pipe and the second oil pipe are welded to the piston rod head on one side along the piston rod body axis and to the connecting rod on the other side, and the first oil pipe and the second oil pipe are connected by a connecting plate welded inside the piston rod body for auxiliary fixation.

[0007] Furthermore, the piston rod head is provided with a first oil inlet and a second oil inlet along the axial direction of the piston rod body, and the connection radius of the first oil inlet is smaller than that of the second oil inlet.

[0008] Preferably, the connecting rod has a second oil outlet along the axial direction of the piston rod body, and a first oil outlet is provided at a position perpendicular to the axial direction of the piston rod body.

[0009] Furthermore, the first oil inlet is concentrically connected to the first oil pipe, and the second oil inlet is eccentrically connected to the second oil pipe, meaning the second oil pipe is closer to the center line of the piston rod.

[0010] Furthermore, the first oil outlet is perpendicularly connected to the first oil pipe, and the second oil outlet is concentrically connected to the second oil pipe.

[0011] Furthermore, a retaining ring is welded to the piston rod body at the connection point with the connecting rod.

[0012] Preferably, the piston rod body has a connecting sleeve welded to the end near the connecting rod.

[0013] Furthermore, a piston is connected to the connecting rod port, dividing the external area connected to the oil outlet into a rod chamber and a rodless chamber. The rod chamber is the external area connected to the first oil outlet, and the rodless chamber is the external area connected to the second oil outlet.

[0014] Furthermore, the piston rod body is welded to the piston rod head and the connecting rod.

[0015] This utility model discloses a hollow piston rod. By hollowing out the piston rod, two oil pipes are welded into the hollow part to replace the traditional oil circuit, creating a new type of piston rod with a three-section structure of oil inlet, oil passage, and oil outlet. Compared with traditional hollow piston rods, this piston rod has higher strength and is lighter than solid piston rods, while still having sufficient strength to meet working requirements. At the same time, the oil circuit inside the piston rod eliminates the need for oil nozzle design during cylinder machining, thereby simplifying the cylinder machining process and improving space utilization. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a hollow piston rod according to the present invention.

[0017] Figure 2 This is a schematic diagram of the overall structure of the hollow piston rod of this utility model assembled in the oil cylinder.

[0018] The labels in the attached diagram are as follows: 1. Piston rod body, 2. Piston rod head, 3. Retaining ring, 4. Connecting sleeve, 5. First oil pipe, 6. Second oil pipe, 7. First oil outlet, 8. Second oil outlet, 9. First oil inlet, 10. Second oil inlet, 11. Connecting rod, 12. Connecting plate, 13. Piston, 14. Rodless chamber, 15. Rod chamber, 16. Oil cylinder. Detailed Implementation

[0019] To enable those skilled in the art to further understand the features and technical content of this utility model, please refer to the following detailed description and drawings of this utility model.

[0020] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0021] Example 1, please refer to Figure 1 or Figure 2 As shown in the accompanying drawings, the present invention will now be described in further detail. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show aspects relevant to this invention.

[0022] The composition related to the utility model.

[0023] Depend on Figure 1 The piston rod head 2 shown adopts a T-shaped cross-section structure. Its longitudinal flange and transverse web form a high-strength load-bearing frame, which significantly improves bending stiffness and torsional performance. The first oil inlet 9 and the second oil inlet 10 are formed by internal drilling.

[0024] exist Figure 1 The piston rod head 2 design shown adopts a T-section structure, in which the longitudinal flange and the transverse web rod are combined to form a high-strength load-bearing frame. The longitudinal flange is mainly responsible for bearing axial force and providing greater bending resistance, while the transverse web rod enhances structural stability and greatly improves the overall torsional performance. The synergistic effect of the two allows the piston rod head to effectively resist bending and torsional forces in complex working environments, thereby significantly improving bending stiffness and torsional performance and ensuring stable operation of the equipment.

[0025] Furthermore, by performing precision drilling inside the piston rod head, a first oil inlet 9 and a second oil inlet 10 are formed. The setting of these oil inlets can precisely control the entry and exit of hydraulic oil, providing necessary support for the power transmission and operation of the equipment, and optimizing the working efficiency and performance of the equipment.

[0026] In this embodiment, a precision drilling process is used inside the connecting rod 11 to form a dual oil outlet system, with a first oil outlet 7 and a second oil outlet 8 provided. Figure 2As shown, the piston 13 is fixed at the oil outlet end of the connecting rod 11. The piston 13 divides the space inside the cylinder 16 into two sides. The end from the piston 13 toward the piston rod head 2 is the rod chamber 15 region, and the opposite direction from the piston 13 toward the piston rod head 2 is the rodless chamber 14 region. The first oil outlet 7 is connected to the rod chamber 15 region, and the second oil outlet 8 is connected to the rodless chamber 14 region.

[0027] like Figure 1 As shown, the hydraulic system of the piston rod includes two parallel oil pipes, labeled as the first oil pipe 5 and the second oil pipe 6. The front end of the first oil pipe 5 is fully welded to the first oil inlet 9 of the piston rod head 2 via a circumferential weld, and its rear end is fully welded to the corresponding first oil outlet 7 of the connecting rod 11. During operation, the welder must strictly follow the welding specifications and adjust parameters such as welding current, voltage, and welding speed to ensure that the weld is uniform, continuous, and free of defects such as porosity and slag inclusions, thereby obtaining sufficient connection strength. The welding process of the second oil pipe 6 is consistent with that of the first oil pipe 5, using the same sufficiently strong welding process to rigidly connect it to the piston rod head 2 and the connecting rod 11.

[0028] 5 and the second oil pipe 6 are welded to the connecting plate 12 inside the piston rod body 1 for auxiliary fixation. The two oil pipes are firmly connected together by welding, which further enhances the stability of the two oil pipes inside the piston rod body 1 and prevents the system performance from being affected by the shaking of the oil pipes during system operation. After welding, the weld seam needs to be ground and, if necessary, post-weld heat treatment should be performed to eliminate residual stress.

[0029] like Figure 1 As shown, the connection between the first oil pipe 5 and the piston rod head 2 is connected to the first oil inlet 9 in the piston rod head 2, and the centerline of the first oil inlet 9 is coaxial with the first oil pipe 5. A precise connection structure is achieved at the joint through precision machining. The key feature of this connection structure is that this precision alignment design is achieved through a three-point positioning pin and an end face stop, effectively reducing the turbulence of hydraulic oil in the transition section, ensuring both connection strength and vibration resistance.

[0030] Reliable sealing under certain conditions.

[0031] The connection between the second oil pipe 6 and the piston rod head 2 is connected to the second oil inlet of the piston rod head 2. The overall structural design of the piston rod head 2 and the connecting rod 11 should be fully considered to avoid mutual interference between oil ports or oil passages, ensure that the oil ports are reasonably distributed, can work in coordination with surrounding components, and make full use of limited space resources. The center line of the second oil inlet 10 is eccentrically connected to the axis of the second oil pipe 6, and the axis of the second oil pipe 6 is close to the center line of the piston rod.

[0032] like Figure 1As shown, the connection between the first oil pipe 5 and the connecting rod 11 is connected to the first oil outlet 7 of the connecting rod 11. The first oil outlet 7 is vertically and smoothly connected to the first oil pipe 5. The vertical flow channel is emptied by gravity assistance, which can shorten the hydraulic oil return time when the machine stops.

[0033] The connection between the second oil pipe 6 and the connecting rod 11 is connected to the second oil outlet 8 of the connecting rod 11. The center line of the second oil outlet 8 is smoothly and concentrically connected to the axis of the second oil pipe 6. This smooth and concentric connection ensures that the oil flows through the connection with minimal frictional resistance and a stable flow rate throughout the entire process of flowing from the second oil pipe 6 into the second oil outlet 8 and flowing out of the second oil outlet 8.

[0034] This oil circuit design ensures easy cleaning of the oil pipe holes, guarantees the cleanliness of the hydraulic cylinder oil, prevents contamination of the hydraulic cylinder seals, effectively extends the service life of the hydraulic cylinder, and improves the working performance and reliability of the entire hydraulic system.

[0035] Thus, the hydraulic control process is as follows: the oil first enters the first oil pipe 5 through the first oil inlet 9, then enters the first oil outlet 7 through the first oil pipe 5, and finally flows through the first oil outlet 7 into the rod chamber 15 region, pushing the piston to move towards the rodless chamber 14 region. The oil enters the second oil pipe 6 through the second oil inlet 10, then enters the second oil outlet 8 through the second oil pipe 6, and finally flows through the second oil outlet 8 into the rodless chamber 14 region, pushing the piston to move towards the rod chamber 15 region.

[0036] In a hydraulic system, the presence of the piston rod is a key factor. Because the piston rod occupies part of the space in the rod chamber 15, the actual volume of the rod chamber 15 is smaller than that of the rodless chamber 14. According to the principle of flow continuity in fluid mechanics, the volume of fluid flowing into different volume regions in the same amount of time is proportional to the volume of that region. Therefore, when the hydraulic system is working, the amount of oil required to flow to the rod chamber 15 is necessarily less than the amount of oil required to flow to the rodless chamber 14.

[0037] Based on the aforementioned flow differences, in the system's oil circuit design, the first oil inlet 9, the first oil pipe 5, and the first oil outlet 7 serve as oil passages leading to the rod chamber 15, with their opening radii slightly lower than those of the second oil inlet 10, the second oil pipe 6, and the second oil outlet 8, respectively. This design can precisely match the flow requirements of different chambers, ensuring the reasonable distribution and smooth flow of oil within the system, thereby optimizing the working efficiency of the entire hydraulic system.

[0038] The hollow section of the piston rod is replaced by two welded oil pipes instead of the traditional oil passage, resulting in a hollow piston rod with a three-section structure of oil inlet, oil outlet, and oil outlet. This invention provides a higher efficiency compared to traditional hollow piston rods.

[0039] Compared to solid piston rods, it is lighter and has sufficient strength to meet working requirements. At the same time, the oil passage inside the piston rod eliminates the need for oil nozzle design during cylinder machining, thereby simplifying the cylinder machining process, overcoming the limitations of the oil inlet installation space, and improving space utilization.

[0040] A retaining ring 3 is welded to the piston rod body 1 at the connection point with the connecting rod 11. The retaining ring 3, through its rigid structure, effectively prevents excessive displacement of the piston rod under pressure, avoiding abnormal equipment operation due to excessive displacement. Under high-pressure conditions, if the piston rod is continuously subjected to high-intensity compression, it is very likely to exceed its elastic deformation limit and undergo plastic deformation, which will seriously affect the performance and service life of the piston rod. The presence of the retaining ring 3, by dispersing pressure and limiting the degree of compression, greatly reduces the risk of plastic deformation of the piston rod, effectively ensuring the structural integrity and mechanical performance stability of the piston rod under complex pressure environments.

[0041] The retaining ring 3 also has a contaminant blocking function. In actual working scenarios, contaminants such as dust and water vapor can corrode the piston rod structure once they enter the piston rod, accelerating the wear of parts and even causing corrosion of the internal structure, thus affecting the operational reliability of the entire equipment. With its unique position of being welded around the connection, the retaining ring 3 acts like a tight protective ring, effectively blocking the intrusion path of contaminants such as dust and water vapor. It isolates these potentially harmful substances from the outside of the piston rod, creating a relatively clean and stable working environment for the precision structure inside the piston rod. This significantly improves the operational stability and service life of the equipment, and reduces equipment failures and maintenance costs caused by contaminant intrusion.

[0042] The piston rod 1 is welded to the end near the connecting rod 11 with a connecting sleeve 4. The surface is smooth after welding, reducing the possibility of impurities getting stuck in the gap. This high-strength and high-reliability connection scheme is suitable for scenarios that need to withstand extreme loads, high-frequency vibrations, or harsh environments. For example, in the power transmission system of heavy machinery, the piston rod often has to withstand huge pressure and tension generated during the operation of the machinery. The welded structure of the connecting sleeve 4, with its high strength characteristics, can steadily withstand these extreme loads, ensuring the stability and reliability of power transmission.

[0043] In the manufacturing process of the hollow piston rod of this utility model, the piston rod head 2 and the connecting rod 11 are first precision drilled to create various oil ports. When determining the position and arrangement of the oil ports, the overall structural design of the piston rod head 2 and the connecting rod 11 must be fully considered to avoid interference between the oil ports or oil passages, ensure that the oil ports are reasonably distributed, and work in coordination with the surrounding components to make full use of the limited space resources. For example, the reason for the eccentric connection of the second oil inlet 10 and the second oil pipe 6 is due to the smaller size of the connecting rod 11.

[0044] Select appropriately sized oil pipes for welding, such as the two ends of the first oil pipe 5 and the second oil pipe 6, and weld them to the piston rod head 2 and the connecting rod 11 respectively. To enhance stability, a connecting plate 12 needs to be welded between the first oil pipe 5 and the second oil pipe 6 inside the piston rod body to achieve auxiliary fixation, thus forming the piston rod assembly. Before formal welding, it is essential to perform thorough surface treatment. For example, the welding area should be carefully cleaned with acetone to completely remove adhering grease and other impurities, creating favorable conditions for subsequent welding.

[0045] During the process, it is necessary to strictly follow the established welding process specifications and control key parameters such as welding current, voltage and welding speed to ensure that the weld is uniform and strong.

[0046] Figure 1 The piston rod 1 is hollowed out and lightweight, which reduces motion inertia and improves the response speed of the equipment. The retaining ring 3 is welded to the area where it will be connected to the port of the connecting rod 11. The connecting sleeve 4 is welded at the port of the piston rod 1. The components can be reliably fixed by means of threads, flanges or retaining rings to ensure efficient transmission of axial force. After welding, the piston rod assembly is formed.

[0047] Finally, the piston rod body assembly and the piston rod head assembly are welded together, thus forming a new type of piston rod with a three-section welded structure integrating oil inlet, oil outlet, and oil flow. For example... Figure 2 In the embodiment shown, oil can be supplied through the first oil inlet.

[0048] The oil enters the first oil pipe 5, then flows through the first oil pipe 5 into the first oil outlet 7, and finally flows through the first oil outlet 7 into the rod chamber 15 area, pushing the piston to move towards the rodless chamber 14 area. The oil enters the second oil pipe 6 from the second oil inlet 10, then flows through the second oil pipe 6 into the second oil outlet 8, and finally flows through the second oil outlet 8 into the rodless chamber 14 area, pushing the piston to move towards the rod chamber 15 area. The piston rod of this utility model has higher strength than the traditional hollow piston rod, is lighter than the solid piston rod, and has sufficient strength to meet the working requirements. At the same time, the oil passage set in the piston rod can eliminate the need for the oil nozzle design when machining the oil cylinder 16, thereby simplifying the machining process of the oil cylinder 16 and improving the space utilization rate.

[0049] The present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A hollow piston rod comprising a cylinder and a piston rod, characterized in that The piston rod includes a piston rod body (1) and a piston rod head (2). The piston rod head (2) is connected to one end of the piston rod body (1). The piston rod body (1) has a connecting rod (11) at the other end of the piston rod head (2). The piston rod body (1) is hollow inside along the axial direction and has two oil pipes connecting the piston rod head (2) and the connecting rod (11).

2. A hollow piston rod according to claim 1, characterized in that The two oil pipes are respectively labeled as first oil pipe (5) and second oil pipe (6). First oil pipe (5) and second oil pipe (6) are welded to piston rod head (2) on one side along the axial direction of piston rod body (1) and to connecting rod (11) on the other side. First oil pipe (5) and second oil pipe (6) are connected by a connecting plate (12) inside piston rod body (1) for auxiliary fixation.

3. A hollow piston rod according to claim 2, characterized in that The piston rod head (2) has a first oil inlet (9) and a second oil inlet (10) along the axial direction of the piston rod body (1), and the connecting radius of the first oil inlet (9) is smaller than that of the second oil inlet (10).

4. A hollow piston rod according to claim 2, characterized in that, The connecting rod (11) has a second oil outlet (8) inside along the axial direction of the piston rod body (1), and a first oil outlet (7) is provided at a position perpendicular to the axial direction of the piston rod body (1).

5. A hollow piston rod according to claim 3, characterized in that The first oil inlet (9) is concentrically connected to the first oil pipe (5), and the second oil inlet (10) is eccentrically connected to the second oil pipe (6), that is, the second oil pipe (6) is closer to the center line of the piston rod (1).

6. A hollow piston rod according to claim 4, characterized in that The first oil outlet (7) is vertically connected to the first oil pipe (5), and the second oil outlet (8) is concentrically connected to the second oil pipe (6).

7. A hollow piston rod according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that The piston rod (1) has a retaining ring (3) welded at the connection point with the connecting rod (11).

8. A hollow piston rod according to claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that The piston rod (1) is welded with a connecting sleeve (4) near the end of the connecting rod (11).

9. A hollow piston rod according to claim 4, characterized in that The piston (13) is connected at the port of the connecting rod (11), dividing the external area connected to the oil outlet into a rod chamber (15) and a rodless chamber (14). The rod chamber (15) is the external area connected to the first oil outlet (7), and the rodless chamber is the external area connected to the second oil outlet (8).

10. A hollow piston rod according to claim 1 or 2 or 3 or 4 or 5 or 6 or 9, characterized in that The piston rod body (1) is welded to the piston rod head (2) and the connecting rod (11).

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