Double bore hydraulic cylinder

Abstract

To provide a double bore hydraulic cylinder which can obtain a stable hydraulic output, effectively improve the precision of an apparatus, and meet the needs for a large rolling force. [Solution] The double bore hydraulic cylinder comprises a cylinder body 1 and a first piston 2 sealed and attached to the cylinder body, a first oil chamber 7 is formed between the cylinder body and the first piston, a groove extending axially downward is provided at the tip of the first piston, a second piston 3 is further sealed and attached in the groove of the first piston, a second oil chamber 8 is formed between the groove of the first piston and the second piston, the upper surface of the second piston can be made flush with the upper surface of the first piston, the first oil chamber is an annular flow passage, and the second oil chamber is an expandable flow passage. A double piston structure consisting of a first piston and a second piston is adopted.

Description

[Technical field]

[0001] This invention relates to a hydraulic cylinder used in rolling magnetic pole pieces, and more particularly to a double bore hydraulic cylinder. [Background technology]

[0002] The rolling of the pole pieces is an important step in the manufacturing process of lithium-ion batteries, which can increase the adhesive strength between the active material and the foil pieces, prevent peeling when immersed in the electrolyte or when the battery is in use, and can also increase the energy density of the lithium battery. In order to make the thickness of the rolled pole pieces uniform, the stability of the rolling force must be maintained. However, the rolling force source of the roll rolling machine is the hydraulic cylinder, so the accuracy of the hydraulic cylinder is very important for rolling the pole pieces.

[0003] Conventionally, a single-bore hydraulic cylinder is adopted, and the control accuracy of the hydraulic pressure is determined by the hydraulic control valve. As is well known, pressure is equal to pressure multiplied by the working area, so when the hydraulic control valve is selected, the pressure fluctuation of the hydraulic cylinder is positively related to the piston area, so that the larger the diameter of the hydraulic cylinder, the larger the output variation of the hydraulic cylinder. Meanwhile, in order to meet the various rolling force requirements during rolling, the diameter of the hydraulic cylinder of the rolling mill is usually selected to be relatively large. As a result, when rolling with a small rolling force, the output fluctuation of the hydraulic cylinder is relatively significant. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve the above-mentioned shortcomings in the prior art, the present invention aims to provide a double bore hydraulic cylinder to achieve the purpose of improving the accuracy of the device when outputting small and medium pressure. [Means for solving the problem]

[0005] In order to achieve the above object, the technical solution adopted by this utility model is as follows: The double-bore hydraulic cylinder according to this utility model comprises a cylinder body and a first piston sealed and attached to the cylinder body, a first oil chamber is formed between the cylinder body and the first piston, a groove extending downward along the axial direction is provided at the tip of the first piston, a second piston is further provided sealed and attached in the groove of the first piston, a second oil chamber is formed between the groove of the first piston and the second piston, an upper surface of the second piston can be flush with an upper surface of the first piston, the first oil chamber is an annular flow passage, and the second oil chamber is an expandable flow passage.

[0006] As a limitation of this utility model, a guide post extending upward along the axial direction is provided on the bottom of the cylinder body, and a guide groove that fits into the guide post is provided on the bottom of the first piston.

[0007] As a further limitation of the present invention, the guide groove communicates with the groove, and the diameter of the guide groove is smaller than the diameter of the groove.

[0008] As another limitation of the present invention, the outer wall of the cylinder body is provided with a heat sink.

[0009] As a further limitation of the present invention, a contact surface between the first piston and the cylinder body is provided with a PTFE coating, and a contact surface between the second piston and the groove of the first piston is provided with a PTFE coating. Effect of the Invention

[0010] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art: (1) This utility model proposes a completely new double bore hydraulic cylinder that adopts a double piston structure consisting of a first piston and a second piston, unlike the single piston structure of conventional hydraulic cylinders. The double piston can be used alone or in combination. The second piston with a small diameter can be used when a small rolling force needs to be output, while the first piston and the second piston can be used in combination when a large rolling force needs to be output. In this way, by using the second piston when the rolling force is small, the pressure acting area is reduced (the cylinder diameter is reduced), and pressure fluctuations are further reduced, resulting in a more stable hydraulic output, which effectively improves the accuracy of the device and also meets the needs for large rolling forces.

[0011] (2) In this utility model, the first oil chamber is designed as an annular flow passage, which increases the contact area with the cylinder body and promotes heat dissipation, and the annular flow passage design provides a more uniform flow passage, reduces dead zones and vortexes, ensures uniform distribution of the liquid in the hydraulic cylinder, and has a relatively small resistance when the fluid flows, thereby reducing pressure loss. In this utility model, the second oil chamber is designed as an expanding flow passage, which effectively reduces the flow rate of the fluid, reduces the turbulence of the fluid, improves the stability of the work, and further improves the precision of the device.

[0012] (3) In this utility model, the structure of the guide post and guide groove provided between the cylinder body and the first piston ensures linear movement of the first piston within the cylinder body and reduces side friction and wear.

[0013] (4) In this utility model, a heat sink is provided on the outer wall of the cylinder body, which can effectively reduce the temperature of the hydraulic oil, prevent performance degradation due to overheating, maintain an appropriate operating temperature, improve the operating stability of the hydraulic system, reduce the probability of failure, and extend the service life of the hydraulic system and its components.

[0014] (5) In this utility model, a PTFE coating is applied to the contact surfaces of the first and second pistons, which is effective in reducing friction, reducing wear, extending service life, improving sealing performance, and reducing leakage. [Brief description of the drawings]

[0015] Hereinafter, the present invention will be described in more detail in conjunction with the accompanying drawings and specific embodiments. [Figure 1] FIG. 2 is a cross-sectional view showing the structural relationship of one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing the structural relationship of a first piston in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The preferred embodiment of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiment described in this specification is only used to explain and understand the present invention, and is not intended to limit the present invention.

[0017] This utility model discloses a double-bore hydraulic cylinder including a cylinder body 1, a first piston 2, and a second piston 3. As shown in FIG. 1, the cylinder body 1 has a cylindrical structure, a guide post 4 extending upward along the axial direction is provided at the center of the bottom of the cylinder body 1, and a heat sink (not shown) is provided on the outer wall of the cylinder body 1. In this embodiment, the heat sink is made of an aluminum alloy material. As shown in FIG. 2, the first piston 2 has a columnar structure, a guide groove 5 extending upward along the axial direction is provided at the bottom of the cylinder body 1. The guide groove 5 is fitted into the guide post 4. The top of the first piston 2 has a groove 6 extending downward along the axial direction. In this embodiment, the groove 6 is connected to the guide groove 5, and the diameter of the groove 6 is larger than the diameter of the guide groove 5. The second piston 3 has a columnar structure that fits into the groove 6.

[0018] Furthermore, the first piston 2 is sealed and attached to the cylinder body 1 via a conventional seal (such as a seal ring), and the guide groove 5 is fitted into the guide post 4 (a seal is also provided between the guide groove 5 and the guide post 4). When the cylinder body 1 is used as a cylinder for the first piston 2, a first oil chamber 7 is formed between them. As shown in FIG. 1, the first oil chamber 7 is provided around the guide post 4 to form an annular flow passage, a first oil inlet 9 and a first oil outlet communicating with the first oil chamber 7 are both opened in the cylinder body 1, and the first oil inlet 9, the first oil outlet, and the first oil chamber 7 are located on the same plane.

[0019] The second piston 3 is sealed and mounted in a groove 6 of the first piston 2 via a conventional seal (e.g., a seal ring). When the first piston 2 is used as a cylinder for the second piston 3, a second oil chamber 8 is formed between them. As shown in FIG. 1, the second oil chamber 8 is an expandable flow passage, and in this embodiment, it is an inverted cone shape. A second oil inlet 10 and a second oil outlet communicating with the second oil chamber 8 are also opened in the cylinder body 1, and the second oil inlet 10 and the second oil outlet communicate with the second oil chamber 8 via a passage arranged obliquely in the cylinder body 1.

[0020] When the second piston 3 is not pushed up, the upper surface of the second piston 3 is flush with the upper surface of the first piston 2.

[0021] In this embodiment, in order to reduce friction and improve sealing performance, the contact surfaces between the first piston 2 and the cylinder body 1 and the contact surfaces between the second piston 3 and the groove 6 of the first piston 2 are coated with PTFE.

[0022] When this embodiment is applied to a rolling mill, the hydraulic output is divided into three stages, large, medium, and small, and the corresponding pressure fluctuations are also divided into three stages, large, medium, and small. 1. Operating state where the rolling force is small (small level): Oil enters the second oil chamber 8, the second piston 3 is pushed up by the hydraulic force, and applies force to the rolling roll. 2. Medium rolling force operating state (intermediate level): Oil enters the first oil chamber 7, and the first piston 2 is pushed upward together with the second piston 3 by the oil force, applying force to the rolling roll. 3. Operating state with large rolling force (large level): Oil enters the first oil chamber 7 and the second oil chamber 8 at the same time, and the first piston 2 and the second piston 3 are simultaneously pushed upward by the hydraulic force, applying a force to the rolling roll that is the sum of the two forces.

[0023] Although only a double piston structure is disclosed in this embodiment, a multi-piston structure can also be designed based on this principle.

[0024] It should be noted that the above are merely preferred embodiments of the present utility model, and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the above embodiments, those skilled in the art may modify the technical solutions described in the above embodiments or equivalently replace some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model should be included in the protection scope of the present utility model. [Explanation of symbols]

[0025] 1 cylinder body, 2 first piston, 3 second piston, 4 guide post, 5 guide groove, 6 groove, 7 first oil chamber, 8 second oil cavity, 9 first oil inlet, 10 second oil outlet.

Claims

1. The cylinder body includes a first piston that is sealed and attached to the cylinder body, and a first oil chamber is formed between the cylinder body and the first piston. A groove is provided at the tip of the first piston and extends downward along the axial direction, The hydraulic oil pump further includes a second piston sealed in the groove of the first piston, and a second oil chamber is formed between the groove of the first piston and the second piston. An upper surface of the second piston may be flush with an upper surface of the first piston; The first oil chamber is an annular flow passage, and the second oil chamber is an expansion type flow passage. A double bore hydraulic cylinder.

2. A guide post extending upward along the axial direction is provided on the bottom of the cylinder body, and a guide groove that fits onto the guide post is provided on the bottom of the first piston.

2. The double bore hydraulic cylinder according to claim 1.

3. The guide groove is connected to the groove, and the diameter of the guide groove is smaller than the diameter of the groove; 3. The double bore hydraulic cylinder according to claim 2.

4. A heat sink is provided on the outer wall of the cylinder body.

4. The double bore hydraulic cylinder according to claim 1, wherein the first and second bores are arranged parallel to each other.

5. A PTFE coating is provided on a contact surface between the first piston and the cylinder body, and a PTFE coating is provided on a contact surface between the second piston and the groove of the first piston.

5. A double bore hydraulic cylinder as claimed in claim 4.

Images