A new piston and piston rod connection structure and hydraulic cylinder thereof

Abstract

A new type of piston and piston rod connecting structure and its hydraulic cylinder, including piston and piston rod, the threaded end of the piston rod outer circle is equipped with a semicircle arc ring groove, the piston is equipped with a threaded hole along the radial direction, the threaded hole and the semicircle arc ring groove correspond in the radial direction, the inner end of the threaded hole and the semicircle arc ring groove form an arc groove, the arc groove is equipped with a conductive ball, the threaded hole is equipped with a positioning stud, the inner end of the positioning stud is tightly pressed to the corresponding conductive ball, the threaded end of the piston rod outer circle is further equipped with a limiting ring groove, the limiting ring groove is located between the threaded end of the piston rod and the semicircle arc ring groove, the end of the piston is connected with a reinforcing limiting ring installed in the limiting ring groove, the structure is more reliable, the anti-loose performance is better, the effective rated working pressure of the hydraulic cylinder can be significantly increased, and the service life is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, specifically to a novel piston-piston rod connection structure and its hydraulic cylinder. Background Technology

[0002] Hydraulic cylinders are important hydraulic actuators, widely used in the hydraulic systems of various machines. The connection between the piston rod and piston in existing hydraulic cylinders is generally a triangular thread connection. To prevent the piston from loosening, the existing assembly method of piston rod and piston is as follows: first, the piston rod and piston are threaded together, then a drill is installed at the radial position of the connection, then the two are removed, the iron filings and burrs on the piston and piston rod are cleaned, and finally they are reassembled and fixed together with fastening screws. This assembly method has the following disadvantages: (1) When drilling, the piston rod is already equipped with a guide sleeve, which is not only inconvenient for hoisting, but also makes it easy for iron filings to cause secondary pollution to the already cleaned workpiece; (2) There are many installation steps, which affects the assembly efficiency; (3) The piston rod surface has an electroplated layer, and repeated disassembly and assembly can easily damage the plating layer, causing the product to be reworked or scrapped.

[0003] Chinese utility model patent CN202022463301.1 discloses a novel anti-loosening piston rod, comprising a piston and a piston rod. The piston has a threaded hole at its center, and the piston rod has a threaded end corresponding to the threaded hole. The piston has a radial through hole communicating with the threaded hole. An annular groove is formed on the outer circumference of the threaded end corresponding to the radial through hole. A positioning pin is disposed within the radial through hole, and the inner end of the positioning pin is engaged in the annular groove. It also provides a hydraulic cylinder with the aforementioned novel anti-loosening piston rod. This novel anti-loosening piston rod and the hydraulic cylinder with it overcome the shortcomings of existing piston rod and piston assembly methods, offering advantages such as one-time assembly, high assembly efficiency, no secondary pollution, and resistance to plating wear. However, for high-pressure hydraulic cylinders used in coal mine hydraulic supports supporting jacks, the working fluid pressure is generally above 35 MPa. Simply engaging the positioning pin in the annular groove still carries the risk of relative axial movement between the piston and piston rod. The positioning pin is subject to significant shear force and is prone to wear or deformation, potentially leading to failure. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a novel piston-piston rod connection structure and its hydraulic cylinder.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a novel piston and piston rod connection structure, comprising a piston and a piston rod, wherein the central hole of the piston is threadedly connected to the threaded end of the piston rod, the outer circumference of the threaded end of the piston rod is provided with a semi-circular arc groove, the piston is provided with a threaded through hole along the radial direction, the threaded through hole is radially corresponding to the semi-circular arc groove, the inner end of the threaded through hole and the semi-circular arc groove form an arc groove, a conductive ball is installed in each arc groove, the outer contour of the conductive ball is adapted to the inner circle of the arc groove, a positioning stud is threadedly installed in the threaded through hole, the inner end of the positioning stud is tightly pressed against the corresponding conductive ball; the outer circumference of the threaded end of the piston rod is also provided with a limiting ring groove, the limiting ring groove is located between the end of the threaded end of the piston rod and the semi-circular arc groove, and the end of the piston is connected to a reinforcing limiting ring installed in the limiting ring groove.

[0006] Based on the above, the reinforcing limiting ring consists of two half-rings, and the two half-rings are connected to the piston by a number of fixing screws.

[0007] Based on the above, the semi-ring is provided with a plurality of countersunk holes, and the end of the piston is provided with threaded blind holes corresponding to each of the countersunk holes. The fixing screw is installed in the countersunk hole, and the inner end of the fixing screw is threadedly connected to the corresponding threaded blind hole.

[0008] Based on the above, a guide ring groove is provided on the outer circle of the piston at the position of the threaded through hole, a guide ring is installed in the guide ring groove, and the guide ring is pressed against the outer end of the positioning stud.

[0009] Based on the above, two threaded through holes are arranged radially symmetrically.

[0010] This utility model also provides a hydraulic cylinder, including the novel piston and piston rod connection structure described above.

[0011] This invention has substantial features and advancements compared to existing technologies. Specifically, the piston and piston rod connection in this invention are fixed in axial position through the cooperation of conductive balls and an arc groove. The conductive balls are pressed and fixed by positioning studs, replacing the existing method of directly inserting positioning pins into an annular groove. This structure is more reliable, has better anti-loosening performance, reduces wear between the piston and piston rod, and increases the working life of the hydraulic cylinder. Furthermore, the addition of a reinforcing limit ring significantly increases the effective rated working pressure of the hydraulic cylinder, meeting the working fluid pressure requirements of the hydraulic support jack in coal mines, preventing failure of the piston-piston rod connection structure, and extending service life.

[0012] Furthermore, since the outer circumference of the threaded end of the piston rod is provided with a semi-circular annular groove, it is only necessary to open the threaded through hole on the piston within the plane of the semi-circular annular groove on the threaded end of the piston rod. This facilitates industrial processing and manufacturing. In this way, it can be ensured that when the piston and the piston rod are tightened and assembled, the threaded through hole and the semi-circular annular groove are radially aligned, ensuring the accurate installation of the conductive ball and the positioning stud, and simplifying the installation process.

[0013] Furthermore, a guide ring is installed on the outer circumference of the piston. The guide ring not only guides the piston but also presses against the positioning stud to prevent it from coming out. This ensures that the conductive balls are always stably confined in the arc groove, keeping the piston and the piston rod tightly connected at all times.

[0014] In summary, this utility model has a more reliable structure, better anti-loosening performance, and can significantly increase the effective rated working pressure of the hydraulic cylinder and extend its service life. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the assembly structure of a hydraulic cylinder using a novel piston and piston rod connection structure according to this utility model.

[0016] Figure 2 This is a schematic diagram of the piston rod of this utility model.

[0017] Figure 3 This is a schematic diagram of the piston structure of this utility model.

[0018] Figure 4 This is an assembly diagram of the piston and piston rod of this utility model.

[0019] In the diagram: 1. Piston; 2. Piston rod; 3. Semi-circular arc groove; 4. Threaded through hole; 5. Conductive ball; 6. Positioning stud; 7. Limiting ring groove; 8. Reinforcing limiting ring; 9. Fixing screw; 10. Threaded blind hole; 11. Guide ring groove; 12. Guide ring; 13. Cylinder block; 14. Cylinder bottom; 15. Guide sleeve. Detailed Implementation

[0020] The technical solution of this utility model will be further described in detail below through specific embodiments.

[0021] like Figures 1-4As shown, a novel piston and piston rod connection structure includes a piston 1 and a piston rod 2. The center hole of the piston 1 is threadedly connected to the threaded end of the piston rod 2. The outer circumference of the threaded end of the piston rod 2 is provided with a semi-circular annular groove 3. Two radially symmetrical threaded through holes 4 are opened on the piston along the radial direction. The threaded through holes 4 are radially corresponding to the semi-circular annular groove 3. The inner end of the threaded through hole 4 and the semi-circular annular groove 3 form an arc groove. Conductive balls 5 (steel balls) are installed in both arc grooves. The outer contour of the conductive balls 5 is parallel to the arc groove. The inner circles of the grooves are compatible, and positioning studs 6 are threadedly installed in both of the two threaded through holes 4. The inner ends of the positioning studs 6 are tightly pressed against the corresponding conductive balls 5. The outer circle of the threaded end of the piston rod 2 is also provided with a limiting ring groove 7. The limiting ring groove 7 is located between the threaded end of the piston rod 2 and the semi-circular arc groove 3. With the threaded end of the piston rod 2 facing backward, the front side of the groove opening of the limiting ring groove 7 is aligned with the rear end of the piston 1. The rear end of the piston 1 is connected to a reinforcing limiting ring 8 installed in the limiting ring groove 7.

[0022] The reinforcing limiting ring 8 consists of two half-rings, which are connected to the piston 1 by a number of fixing screws 9.

[0023] The semi-ring is provided with a plurality of countersunk holes, and the rear end of the piston 1 is provided with threaded blind holes 10 corresponding to each of the countersunk holes. The fixing screw 9 is installed in the countersunk hole, and the inner end of the fixing screw 9 is threadedly connected to the corresponding threaded blind hole 10.

[0024] The piston 1 has guide ring grooves 11 on its outer circumference at the positions of the two threaded through holes 4. Guide rings 12 are installed in the guide ring grooves 11 and press against the outer ends of the two positioning studs 6. The guide rings 12 provide guidance while also pressing the positioning studs 6 to prevent them from coming out, ensuring that the conductive balls 5 are always stably confined in the arc grooves, and keeping the piston 1 and piston rod 2 tightly connected at all times.

[0025] In this invention, the axial position of the piston 1 and piston rod 2 is fixed at the connection point through the cooperation of the conductive ball bearing 5 and the arc groove. The conductive ball bearing 5 is clamped and restricted by the positioning stud 6, replacing the existing method of directly inserting the positioning stud into the annular groove. This structure is more reliable, has better anti-loosening performance, and can also reduce the wear between the piston 1 and piston rod 2, increasing the working life of the hydraulic cylinder. At the same time, the addition of a reinforcing limiting ring 8 can significantly increase the effective rated working pressure of the hydraulic cylinder, which can meet the working fluid pressure requirements of the hydraulic support jack in coal mines, avoid failure of the connection structure between the piston 1 and piston rod 2, and extend the service life.

[0026] Since the outer circumference of the threaded end of the piston rod 2 is provided with a semi-circular annular groove 3, it is only necessary to open the threaded through hole 4 on the piston 1 in the plane where the semi-circular annular groove 3 is located on the threaded end of the piston rod 2. This facilitates industrial processing and manufacturing. In this way, it can be ensured that when the piston 1 and the piston rod 2 are tightened and assembled, the threaded through hole 4 and the semi-circular annular groove 3 are radially aligned, ensuring the accurate installation of the conductive ball 5 and the positioning stud 6. The installation is simple.

[0027] like Figure 1 As shown, this utility model also provides a hydraulic cylinder, including the novel piston and piston rod connection structure described above.

[0028] The hydraulic cylinder also includes a cylinder body 13, a cylinder bottom 14, and a guide sleeve 15. During the specific installation of the hydraulic cylinder:

[0029] (1) After cleaning the guide sleeve 15, install the relevant sealing components on the guide sleeve 15;

[0030] (2) After cleaning the piston rod 2, install the guide sleeve 15 on the piston rod 2 so that the guide sleeve 15 and the piston rod 2 are assembled into a component;

[0031] (3) Install the relevant seals on the piston rod 2 and the piston 1, and then tighten the piston 1 onto the threaded end of the piston rod 2, so that the piston 1 becomes part of the assembly;

[0032] (4) With one of the threaded through holes 4 facing upward, a conductive ball 5 is installed into the threaded through hole 4, and a positioning stud 6 is installed into the threaded through hole 4. The corresponding conductive ball 5 is pressed. Then, with another threaded through hole 4 facing upward, a conductive ball 5 and a positioning stud 6 are installed into another threaded through hole 4 respectively. Next, the guide ring 12 is installed into the guide ring groove 11 of the piston 1. Then, the two half rings are installed in the limiting ring groove 7 to form the reinforcing limiting ring 8. The two half rings are fixedly connected to the end of the piston 1 using the fixing screw 9.

[0033] (5) The assembly consisting of the piston 1, the piston rod 2 and the guide sleeve 15 is installed into the cylinder body 13, and then the guide sleeve 15 is tightened to complete the assembly of the hydraulic cylinder.

[0034] Compared to traditional hydraulic cylinders with a piston-piston rod connection, this assembly method eliminates the drilling process, preventing secondary contamination of the cleaned workpiece by drilling shavings after piston-piston rod assembly. It also avoids repeated disassembly and assembly, minimizing damage to the plating and reducing product rework or scrap. Furthermore, it reduces installation steps, improving assembly efficiency, and eliminates the need for re-disassembly and cleaning after drilling, facilitating automated assembly. Therefore, the assembly method using this new piston-piston rod connection structure also offers advantages such as one-time assembly, high assembly efficiency, no secondary contamination, and reduced plating wear.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A novel piston-piston rod connection structure, comprising a piston and a piston rod, wherein the central hole of the piston is threadedly connected to the threaded end of the piston rod, characterized in that: The piston rod has a semi-circular annular groove on its threaded end outer circumference. A threaded through hole is radially formed on the piston, corresponding radially to the semi-circular annular groove. The inner end of the threaded through hole and the semi-circular annular groove form an arc groove. Conductive balls are installed within the arc groove, their outer contours matching the inner circle of the arc groove. A positioning stud is threaded into the threaded through hole, its inner end pressing against the corresponding conductive ball. The piston rod also has a limiting annular groove on its threaded end outer circumference, located between the piston rod's threaded end and the semi-circular annular groove. A reinforcing limiting ring is connected to the piston's end, installed within the limiting annular groove.

2. The novel piston and piston rod connection structure according to claim 1, characterized in that: The reinforcing limiting ring consists of two half-rings, which are connected to the piston by a number of fixing screws.

3. The novel piston and piston rod connection structure according to claim 2, characterized in that: The semi-ring is provided with a number of countersunk holes, and the end of the piston is provided with threaded blind holes corresponding to each of the countersunk holes. The fixing screw is installed in the countersunk hole, and the inner end of the fixing screw is threadedly connected to the corresponding threaded blind hole.

4. The novel piston and piston rod connection structure according to claim 1, characterized in that: The piston has a guide ring groove on its outer circumference at the location of the threaded through hole, and a guide ring is installed in the guide ring groove. The guide ring is pressed against the outer end of the positioning stud.

5. The novel piston and piston rod connection structure according to claim 1, characterized in that: There are two threaded through holes arranged radially symmetrically.

6. A hydraulic cylinder, characterized in that: Including the novel piston and piston rod connection structure as described in any one of claims 1-5.

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