A glue injection cylinder and its usage method

Abstract

This invention discloses a glue injection cylinder and its usage method. The glue injection cylinder includes a cylinder body, a glue injection piston, a piston rod, and a front extension rod. The glue injection piston is disposed within the cylinder body, dividing the internal space of the cylinder body into a first cavity and a second cavity. The first cavity has a first oil port, and the second cavity has a second oil port. One end of the piston rod extends into the first cavity and connects to the glue injection piston, while the other end of the piston rod extends out of the cylinder body. The connection between the piston rod and the cylinder body maintains a sliding seal. One end of the front extension rod extends into the second cavity and connects to the glue injection piston, while the other end of the front extension rod extends out of the cylinder body. The connection between the front extension rod and the cylinder body maintains a sliding seal. This invention adds a front extension rod within the rodless cavity, reducing the cavity volume and cross-sectional area, making it close to the area of ​​the oil port on the same side. During the glue injection process, the hydraulic oil is rapidly discharged, reducing or even eliminating back pressure and increasing the glue injection speed.

Description

Technical Field

[0001] This invention belongs to the field of injection molding technology, specifically relating to an injection cylinder and its usage method. Background Technology

[0002] An injection molding machine is a device that melts plastic granules, applies high pressure, and injects them to fill the mold cavity. The injection speed is greatly affected by the injection cylinder. Existing injection cylinders have structures such as... Figure 1 As shown, the injection process involves hydraulic oil entering the rod chamber to move the piston rod, while hydraulic oil in the rodless chamber is discharged. Conversely, the release process involves hydraulic oil entering the rodless chamber to move the piston rod, while hydraulic oil in the rod chamber is discharged. Currently, injection-produced products are relatively thin, requiring high and controllable injection speeds, while the release speed requirement is not high. However, in existing injection cylinders, during the injection action, the injection piston is on the right, and the left-side chamber has a larger volume, preventing the hydraulic oil in the left-side chamber from being discharged quickly, which significantly affects the injection speed. Therefore, it is necessary to propose a new injection cylinder structure to solve the above problems. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention aims to provide a glue injection cylinder and its usage method. By adding a front rod in the rodless cavity, the cavity volume and cross-sectional area are reduced, making it close to the area of ​​the oil port on the same side. During the glue injection process, the hydraulic oil is quickly discharged, reducing or even eliminating back pressure and increasing the glue injection speed.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a glue injection cylinder, comprising a cylinder body, a glue injection piston, a piston rod, and a front extension rod. The glue injection piston is disposed within the cylinder body, dividing the internal space of the cylinder body into a first cavity and a second cavity. The first cavity is provided with a first oil port, and the second cavity is provided with a second oil port. One end of the piston rod extends into the first cavity and is connected to the glue injection piston. The other end of the piston rod extends out from the end of the first cavity of the cylinder body away from the second cavity. The connection between the piston rod and the cylinder body maintains a sliding seal. One end of the front extension rod extends into the second cavity and is connected to the glue injection piston. The other end of the front extension rod extends out from the end of the second cavity of the cylinder body away from the first cavity. The connection between the front extension rod and the cylinder body maintains a sliding seal.

[0006] Preferably, the cross-sectional circumferential width of the second cavity is greater than or equal to the width of the second oil port.

[0007] Preferably, the injection cylinder also includes a dust cover, which is fitted over the front rod and fixedly connected to the cylinder body.

[0008] More preferably, the length of the dust cover is greater than or equal to the maximum length of the front rod extending from the second cavity, and a cover plate is provided at the end of the dust cover away from the cylinder body, and an exhaust hole is provided at the cover plate.

[0009] Preferably, the end of the piston rod passes through the injection piston and is connected to the front rod.

[0010] More preferably, the injection piston includes a movable piston and a fixed piston. The movable piston is located near the front rod, and the fixed piston is located on the side of the movable piston away from the front rod. The fixed piston is fixedly connected to the piston rod, and the movable piston is fixedly connected to the front rod. The movable piston has a sliding through hole for the piston rod to pass through. The end face of the front rod near the movable piston has a sliding guide groove aligned with the sliding through hole. One end of the piston rod passes through the sliding through hole and is embedded in the sliding guide groove. The end of the piston rod is slidably connected to the movable piston and the front rod. A limiting member is provided at the end of the piston rod embedded in the sliding guide groove to prevent the piston rod from coming out of the sliding guide groove of the front rod. A third cavity is formed between the movable piston and the fixed piston.

[0011] The cylinder body is provided with a third oil port and a fourth oil port on its side. The third oil port is located on the right side of the cylinder body. When the movable piston and the fixed piston move to the rightmost side of the cylinder body, the third oil port is connected to the third cavity. The fourth oil port is located on the left side of the cylinder body. When both the movable piston and the fixed piston move to the leftmost side of the cylinder body, the fourth oil port is connected to the third cavity.

[0012] More preferably, a magnet is provided on the side of the movable piston member facing the fixed piston member, and the fixed piston member is made of ferrous material.

[0013] More preferably, the first oil port, the second oil port, the third oil port and the fourth oil port are respectively connected to the oil pump and the oil tank through pipelines, and solenoid valves are respectively installed on the multiple pipelines.

[0014] In a second aspect, the present invention provides a method of using a glue injection cylinder, including a glue injection action and a release action, as follows:

[0015] Multiple injection cylinders are installed at the injection head plate, and the piston rods of the multiple injection cylinders are on the same side. All piston rods are connected to an external injection device.

[0016] Injection action: Hydraulic oil enters the first chamber from the first oil port, pushing the injection piston to move and compressing the second chamber. The front rod in the second chamber reduces the oil discharge cross-sectional area of ​​the second chamber. The oil discharge cross-sectional area of ​​the second chamber is greater than or equal to the cross-sectional area of ​​the second oil port, which reduces the back pressure in the second chamber during compression. The injection piston drives the piston rod to move to achieve injection.

[0017] Release action: Hydraulic oil enters the second chamber from the second oil port, pushing the injection piston and piston rod to move and reset.

[0018] When the injection piston includes a movable piston and a fixed piston, the usage method is as follows:

[0019] Injection action: Hydraulic oil first enters the third cavity between the movable piston and the fixed piston through the third oil port. The movable piston is pushed by the hydraulic oil. Since the movable piston and the piston rod are slidably connected, the piston rod and the fixed piston are in a stationary state. The movable piston first compresses the space of the second cavity, and discharges part of the hydraulic oil in the second cavity from the second oil port and the fourth oil port.

[0020] When the movable piston moves to its limit position, the limiting part contacts the side of the sliding guide groove closest to the movable piston, closing the third oil port. The hydraulic oil then enters the first cavity from the first oil port, pushing the fixed piston and piston rod to move. At this time, there is hydraulic oil between the fixed piston and the movable piston. Since the hydraulic oil in the second cavity is reduced and discharged through the second and fourth oil ports at the same time, the injection speed is increased.

[0021] When the second chamber is compressed to its minimum, the third chamber between the movable piston and the fixed piston is connected to the fourth oil port. The fixed piston continues to move, discharging the hydraulic oil in the third chamber through the fourth oil port, thus completing the final action of the injection. The movable piston and the fixed piston then re-engage and come into contact.

[0022] Release action: Keep the fourth oil port closed, and hydraulic oil enters the second chamber through the second oil port, pushing the movable piston, fixed piston and piston rod to move and reset.

[0023] Beneficial effects:

[0024] The present invention adds a front extension rod to one side of the second cavity, which reduces the maximum volume of the second cavity and also reduces the cross-sectional area of ​​the effective volume of the second cavity. The cross-sectional width of the effective volume of the second cavity is equal to the diameter of the second oil port. During the injection process, the hydraulic oil in the second cavity can be discharged quickly. The front extension rod extends out of the cylinder along with the movement of the injection piston, effectively reducing or even eliminating back pressure, thereby increasing the injection speed. Attached Figure Description

[0025] Figure 1 The diagram shown is an internal schematic of an existing injection cylinder.

[0026] Figure 2 The figure shown is an overall schematic diagram of Embodiment 1 of the present invention;

[0027] Figure 3The diagram shown is an internal schematic diagram of Embodiment 1 of the present invention;

[0028] Figure 4 The diagram shown is a schematic diagram of the pre-oil draining stage in Embodiment 2 of the present invention;

[0029] Figure 5 The diagram shown is a schematic diagram of the injection stage in Embodiment 2 of the present invention;

[0030] Figure 6 The diagram shown is a schematic diagram of the completed injection stage in Embodiment 2 of the present invention.

[0031] Attached reference numerals: 1-Injection head plate, 2-Injection cylinder;

[0032] 201-Cylinder body, 202-Injection piston, 203-Piston rod, 204-Front rod, 205-First chamber, 206-Second chamber, 207-Dust cover, 208-Exhaust port, 209-Moving piston, 210-Fixed piston, 211-First oil port, 212-Second oil port, 213-Third oil port, 214-Fourth oil port, 215-Sliding guide groove, 216-Limiting component, 217-Third chamber. Detailed Implementation

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0034] The technical solution of the present invention will be described in detail below with specific embodiments.

[0035] Example 1

[0036] In this embodiment, the present invention provides a glue injection cylinder 2, including a cylinder body 201, a glue injection piston 202, a piston rod 203, and a front ejector rod 204, as shown below. Figure 2-3As shown, the injection piston 202 is disposed inside the cylinder 201, dividing the inner cavity of the cylinder 201 into a first cavity 205 and a second cavity 206. The first cavity 205 is provided with a first oil port 211, and the second cavity 206 is provided with a second oil port 212. One end of the piston rod 203 extends into the first cavity 205 on the left side of the cylinder 201 and is connected to the injection piston 202. The other end of the piston rod 203 extends out from the end of the first cavity 205 of the cylinder 201 away from the second cavity 206. The connection between the piston rod 203 and the cylinder 201 maintains a sliding seal. One end of the front rod 204 extends into the second cavity 206 on the right side of the cylinder 201 and is disposed on the left side of the injection piston 202. The other end of the front rod 204 extends out from the end of the second cavity 206 of the cylinder 201 away from the first cavity 205. The connection between the front rod 204 and the cylinder 201 maintains a sliding seal.

[0037] The cylinder body 201, the injection piston 202, and the piston rod 203 form a structure similar to an existing hydraulic cylinder. Hydraulic oil enters the first chamber 205, pushing the injection piston 202 towards the second chamber 206, whereby the hydraulic oil in the second chamber 206 is discharged. Externally, this is manifested as the piston rod 203 retracting into the cylinder body 201, which is the injection action. Conversely, hydraulic oil entering the second chamber 206 pushes the injection piston 202 towards the first chamber 205, whereby the hydraulic oil in the first chamber 205 is discharged. Externally, this is manifested as the piston rod 203 extending out of the cylinder body 201, which is the release action. During the injection action, the hydraulic oil discharge rate in the second chamber 206 is related to the injection speed, and the hydraulic oil discharge rate in the second chamber 206 is related to the amount of oil in the chamber before the injection action. The existing injection cylinder 2 generates back pressure during the injection process. In this invention, a front extension rod 204 is added to one side of the second cavity 206, reducing the maximum volume of the second cavity 206 and also reducing the effective cross-sectional area of ​​the second cavity 206. The effective cross-sectional area of ​​the second cavity 206 is close to the cross-sectional area of ​​the second oil port 212. Specifically, after the front extension rod 204 is set, the cross-section of the second cavity 206 is annular, and its ring width is close to the width of the second oil port 212. For example, if the cross-section of the second oil port 212 is circular, the ring width of the cross-section of the second cavity 206 is equal to the diameter of the second oil port 212. During the injection process, the hydraulic oil in the second cavity 206 can be quickly discharged, and the front extension rod 204 extends out of the cylinder 201 following the movement of the injection piston 202, effectively reducing or even eliminating back pressure, thereby increasing the injection speed.

[0038] like Figure 3 As shown, two injection cylinders 2 are installed at both ends of the injection head plate 1, and the piston rods 203 of the two injection cylinders 2 are on the same side, that is... Figure 3 On the right side of the viewpoint, the front extension rods 204 of the two injection cylinders 2 are also on the same side, that is... Figure 3From the left side of the viewpoint, oil is simultaneously supplied to the first chamber 205 of both injection cylinders 2, pushing the injection piston 202 towards the second chamber 206, and both injection cylinders 2 simultaneously perform injection actions. Similarly, oil is simultaneously supplied to the second chamber 206 of both injection cylinders 2, pushing the injection piston 202 towards the first chamber 205, and both injection cylinders 2 simultaneously perform release actions.

[0039] It is easy to understand that the connection between the piston rod 203 and the cylinder 201 is designed to be sealed without affecting the movement of the piston rod 203. Dust seals, rod seals, and O-rings are installed at this connection. Similarly, the connection between the front extension rod 204 and the cylinder 201 is also designed to be sealed without affecting the movement of the front extension rod 204. Dust seals, rod seals, and O-rings are also installed at this connection.

[0040] In this invention, the length of the front extension rod 204 is greater than the length of the second cavity 206 when it reaches its maximum. The front extension rod 204 can be considered as a structure similar to the piston rod 203. The difference between the front extension rod 204 and the piston rod 203 is that the front extension rod 204 is not connected to other components of the injection machine, and it does not directly participate in the injection process during the injection or release action. The function of the front extension rod 204 is to change the volume of the second cavity 206 and the cross-sectional area of ​​the effective oil storage space within the second cavity 206, thereby reducing the back pressure.

[0041] like Figure 2-3 As shown, the injection cylinder 2 also includes a dust cover 207, which is fitted over the front extension rod 204 and fixedly connected to the cylinder body 201. To improve dust protection, a cover plate is provided at the end of the dust cover 207, i.e., the end furthest from the cylinder body 201. An exhaust port 208 is provided at the cover plate to reduce the possibility of external dust contacting the front extension rod 204. The length of the dust cover 207 is greater than or equal to the maximum extended length of the front extension rod 204. During the extension or retraction of the front extension rod 204, it remains within the dust cover 207, effectively preventing foreign objects from falling onto the front extension rod 204 and avoiding any impact on the connection between the front extension rod 204 and the cylinder body 201.

[0042] Preferred, such as Figure 3 As shown, the end of the piston rod 203 passes through the injection piston 202 and is connected to the front rod 204.

[0043] In this embodiment, the method of using the injection cylinder 2 includes injection and release actions, as detailed below.

[0044] Multiple injection cylinders 2 are installed at the injection head plate 1, and the piston rods 203 of the multiple injection cylinders 2 are on the same side. All piston rods 203 are connected to an external injection device.

[0045] Injection action: Hydraulic oil enters the first chamber 205 from the first oil port 211, pushing the injection piston 202 to move and compressing the second chamber 206. The front rod 204 in the second chamber 206 reduces the oil discharge cross-sectional area of ​​the second chamber 206 and brings it closer to the second oil port 212, thereby reducing the back pressure during the compression process of the second chamber 206. The injection piston 202 drives the piston rod 203 to move to achieve injection.

[0046] Release action: Hydraulic oil enters the second chamber 206 from the second oil port 212, pushing the injection piston 202 and piston rod 203 to move and reset.

[0047] Example 2

[0048] Example 1 solved the problem of back pressure during the injection process. Based on Example 1, this example makes overall improvements to the injection cylinder 2 in order to further increase the injection speed, as detailed below:

[0049] The injection piston 202 includes a movable piston 209 and a fixed piston 210. The movable piston 209 is located near the front rod 204, and the fixed piston 210 is located on the side of the movable piston 209 away from the front rod 204. The fixed piston 210 is fixedly connected to the piston rod 203, and the movable piston 209 is fixedly connected to the front rod 204. The movable piston 209 is provided with a sliding through hole to facilitate the passage of the piston rod 203. The end face of the front rod 204 near the movable piston 209 is provided with a sliding guide groove 215, which is aligned with the sliding through hole. One end of the piston rod 203 passes through the sliding through hole and is embedded in the sliding guide groove 215. That is, the end of the piston rod 203 is slidably connected to the movable piston 209 and the front rod 204. The end of the piston rod 203 embedded in the sliding guide groove 215 is provided with a limiting member 216 to prevent the piston rod 203 from coming out of the sliding guide groove 215 of the front rod 204.

[0050] It is easy to understand that the installation method of the limiting member 216 in the sliding guide groove 215 can be varied. The following is one feasible solution: The end of the front rod 204 includes a detachable mounting plate. The mounting plate has a through hole adapted to the piston rod 203. After the sliding guide groove 215 is opened at the end of the front rod 204, the limiting member 216 and the end of the piston rod 203 are first placed into the sliding guide groove 215. Then, the mounting plate is inserted from the other end of the piston 203, and the mounting plate is sealed and connected to the front rod 204.

[0051] In this embodiment, sealing rings, O-rings, and other sealing elements are provided at the opening of the sliding guide groove 215 of the front extension rod 204 (i.e., the inner wall of the through hole in the mounting plate mentioned above) to ensure a sliding seal between the front extension rod 204 and the piston rod 203. Similarly, sealing rings, O-rings, and other sealing elements are also provided on the side of the movable piston 209 that contacts the piston rod 203 to ensure a sliding seal between the movable piston 209 and the piston rod 203.

[0052] It is easy to understand that there is a gap between the movable piston 209 and the fixed piston 210, which serves as the third cavity 217. The size of this gap is related to the distance the end of the piston rod 203 moves within the sliding guide hole. Figure 4 As shown, a third oil port 213 and a fourth oil port 214 are respectively provided on the side of the cylinder body 201. The third oil port 213 is located on the right side of the cylinder body 201. When the movable piston 209 and the fixed piston 210 move to the rightmost side of the cylinder body 201, the volume of the second chamber 206 reaches its maximum, the volume of the first chamber 205 reaches its minimum, and the volume of the third chamber 217 also reaches its minimum. The third oil port 213 is connected to the third chamber 217. The fourth oil port 214 is located on the left side of the cylinder body 201. When both the movable piston 209 and the fixed piston 210 move to the leftmost side of the cylinder body 201, the volume of the first chamber 205 reaches its maximum, the volume of the second chamber 206 reaches its minimum, and the volume of the third chamber 217 also reaches its minimum. The fourth oil port 214 is connected to the third chamber 217.

[0053] In this embodiment, since the injection piston 202 is divided into a movable piston 209 and a fixed piston 210, the injection action is also improved accordingly. The usage method of this embodiment is as follows:

[0054] Injection action: Hydraulic oil first enters the third cavity 217 between the movable piston 209 and the fixed piston 210 through the third oil port 213. The movable piston 209 is pushed by the hydraulic oil. Since the movable piston 209 and the piston rod 203 are slidably connected, the piston rod 203 and the fixed piston 210 are in a stationary state. The movable piston 209 first compresses the space of the second cavity 206, and discharges part of the hydraulic oil in the second cavity 206 from the second oil port 212 and the fourth oil port 214.

[0055] When the movable piston 209 moves to its limit position, the third oil port 213 is closed, and the hydraulic oil enters the first cavity 205 from the first oil port 211, pushing the fixed piston 210 and piston rod 203 to move. At this time, there is hydraulic oil between the fixed piston 210 and the movable piston 209. Since the hydraulic oil in the second cavity 206 is reduced and discharged through the second oil port 212 and the fourth oil port 214 at the same time, the injection speed is increased.

[0056] When the second chamber 206 is compressed to its minimum, the third chamber 217 between the movable piston 209 and the fixed piston 210 is connected to the fourth oil port 214. The fixed piston 210 continues to move, and the hydraulic oil in the third chamber 217 is discharged through the fourth oil port 214 to realize the injection action. The movable piston 209 and the fixed piston 210 re-fit and contact each other.

[0057] Release action: Keep the fourth oil port 214 closed, and the hydraulic oil enters the second chamber 206 through the second oil port 212, pushing the movable piston 209, the fixed piston 210, and the piston rod 203 to move and reset.

[0058] Combined with appendix Figure 4-6 In this embodiment, the injection process is divided into a pre-oil discharge stage and an injection stage. For example... Figure 4 As shown, during the pre-drainage stage, only the movable piston 209 moves. Based on the usage method of this embodiment, when the hydraulic oil first enters the third chamber 217 through the third port 213, the hydraulic oil can only act on the movable piston 209, pushing it to the left. The fixed piston rod 203 is located on the far right of the cylinder 201, and the hydraulic oil cannot push it to move. Due to the leftward movement of the movable piston rod 203, some of the hydraulic oil in the second chamber 206 is discharged first, reducing the space within the second chamber 206 and decreasing the amount of hydraulic oil it contains.

[0059] During the process of the movable piston 209 moving independently to the left, the front rod 204 and the movable piston 209 actually undergo relative sliding displacement with the end of the piston rod 203. At this time, the piston is not subject to the resistance generated by the connection between the piston rod 203 and the external equipment, and can move quickly to the left. After the front rod 204 moves to the limit position along the end of the piston rod 203, the movable piston 209 can no longer move independently to the left and enters the injection stage.

[0060] like Figure 5As shown, during the injection stage, the third port 213 is closed, and no more oil enters. Hydraulic oil enters the first chamber 205 from the first port 211, pushing the fixed piston 210, the movable piston, and the hydraulic oil in the third chamber 217 to move synchronously to the left, driving the piston rod 203 to perform the injection action. The hydraulic oil in the second chamber 206 is discharged simultaneously through the second port 212 and the fourth port 214, thus increasing the injection speed. Since some of the hydraulic oil in the second chamber 206 is discharged first, the space inside the second chamber 206 is reduced, and the injection speed is further increased during the injection stage. When the movable piston 209 moves to the leftmost side of the cylinder 201, the third chamber 217 is connected to the fourth port 214, and the hydraulic oil therein is discharged through the fourth port 214. It is easy to understand that since the volume of the third chamber 217 is small, its oil discharge speed is also relatively fast, and no obvious back pressure is generated. After all the hydraulic oil in the third chamber 217 is discharged, the fixed piston 210 and the movable piston 209 come into contact again, thus completing the entire injection process. Figure 6 As shown.

[0061] In this embodiment, the first oil port 211, the second oil port 212, the third oil port 213, and the fourth oil port 214 are connected to the oil pump and the oil tank via pipelines, respectively. Solenoid valves are installed on each pipeline to control the opening and closing of each oil port. During the injection process, the time it takes for the third chamber 217 to be completely filled with oil is related to the oil pressure of the third oil port 213. Its oil inlet time is determinable and can be controlled by a PLC or other controller to ensure that oil enters first through the third oil port 213 during the injection process. After a certain period, the third oil port 213 is closed while the first oil port 211 is opened simultaneously.

[0062] Example 3

[0063] Based on Embodiment 2, in this embodiment, a magnet is provided on the side of the movable piston 209 facing the fixed piston 210, and the fixed piston 210 is made of ferrous material. When the movable piston 209 and the fixed piston 210 come into contact, they remain in contact under the action of the magnet. It is easy to understand that when oil is introduced into the third chamber 217, the movable piston 209 and the fixed piston 210 can be easily separated.

[0064] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas 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 principles 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 hydraulic ram, characterized in that The application relates to a hydraulic cylinder, which comprises a cylinder (201), a glue injection piston (202), a piston rod (203) and a front rod (204), the glue injection piston (202) is arranged in the cylinder (201) and divides the space in the cylinder (201) into a first cavity (205) and a second cavity (206), the first cavity (205) is provided with a first oil port (211), the second cavity (206) is provided with a second oil port (212), one end of the piston rod (203) extends into the first cavity (205) and is connected with the glue injection piston (202), the other end of the piston rod (203) extends out of the first cavity (205) of the cylinder (201) and away from the second cavity (206), the connection between the piston rod (203) and the cylinder (201) is kept in sliding sealing, one end of the front rod (204) extends into the second cavity (206) and is connected with the glue injection piston (202), the other end of the front rod (204) extends out of the second cavity (206) of the cylinder (201) and away from the first cavity (205), the connection between the front rod (204) and the cylinder (201) is kept in sliding sealing; The end of the piston rod (203) penetrates the glue injection piston (202) and is connected with the front rod (204); The glue injection piston (202) comprises a movable piston part (209) and a fixed piston part (210), the movable piston part (209) is arranged on the side close to the front rod (204), the fixed piston part (210) is arranged on the side away from the front rod (204) of the movable piston part (209), the fixed piston part (210) is fixedly connected with the piston rod (203), the movable piston part (209) is fixedly connected with the front rod (204), the movable piston part (209) is provided with a sliding through hole through which the piston rod (203) penetrates, the end face of the front rod (204) close to the movable piston part (209) is provided with a sliding guide groove (215), the sliding guide groove (215) is aligned with the sliding through hole, one end of the piston rod (203) penetrates the sliding through hole and is embedded in the sliding guide groove (215), the end of the piston rod (203) is in sliding connection with the movable piston part (209) and the front rod (204), the end of the piston rod (203) embedded in the sliding guide groove (215) is provided with a limiting part (216) to prevent the piston rod (203) from being pulled out of the sliding guide groove (215) of the front rod (204), and a third cavity (217) is formed between the movable piston part (209) and the fixed piston part (210). The side of the cylinder (201) is respectively provided with a third oil port (213) and a fourth oil port (214), the third oil port (213) is located at the right side of the cylinder (201), when the movable piston part (209) and the fixed piston part (210) move to the rightmost side in the cylinder (201), the third oil port (213) communicates with the third cavity (217); the fourth oil port (214) is located at the left side of the cylinder (201), when the movable piston part (209) and the fixed piston part (210) move to the leftmost side in the cylinder (201), the fourth oil port (214) communicates with the third cavity (217).

2. The hydrogel-injected cylinder according to claim 1, characterized in that The cross-sectional ring width of the second cavity (206) is greater than or equal to the width of the second oil port (212).

3. The hydrogel-injected cylinder according to claim 1, wherein The glue injection cylinder also comprises a dust cover (207), the dust cover (207) is sleeved outside the front rod (204), and the dust cover (207) is fixedly connected with the cylinder (201).

4. The hydrogel-injected cylinder according to claim 3, characterized in that The length of the dust cover (207) is greater than or equal to the maximum length of the front rod (204) extending from the second cavity (206), and the end of the dust cover (207) away from the cylinder (201) is provided with a cover plate, and the cover plate is provided with an exhaust hole (208).

5. The hydrogel-injected cylinder of claim 1, wherein, The movable piston part (209) is provided with a magnet on the side facing the fixed piston part (210), and the fixed piston part (210) is made of an iron material.

6. The hydrogel-injected cylinder of claim 1, wherein, The first oil port (211), the second oil port (212), the third oil port (213) and the fourth oil port (214) are respectively connected with an oil pump and an oil tank through pipelines, and an electromagnetic valve is arranged on each of the pipelines.

7. A method of using a hydraulic ram comprising: The glue injection cylinder is suitable for the glue injection cylinder according to any one of claims 1-4, comprising a glue injection action and a loose return action, as follows: The glue injection action: hydraulic oil enters the first cavity (205) from the first oil port (211), pushes the glue injection piston (202) to move, and compresses the second cavity (206), the front rod (204) in the second cavity (206) reduces the oil discharge cross-sectional area of the second cavity (206), the oil discharge cross-sectional area of the second cavity (206) is greater than or equal to the cross-sectional area of the second oil port (212), so that the back pressure in the compression process of the second cavity (206) is reduced, and the glue injection piston (202) drives the piston rod (203) to move to realize glue injection; The loose return action: hydraulic oil enters the second cavity (206) from the second oil port (212), pushes the glue injection piston (202) and the piston rod (203) to move and reset.

8. A method of using a hydraulic ram comprising: The glue injection cylinder is suitable for the glue injection cylinder according to any one of claims 1-6, comprising a glue injection action and a loose return action, as follows: Injection action: hydraulic oil enters the third cavity (217) between the movable piston part (209) and the fixed piston part (210) through the third oil port (213), the movable piston part (209) is first pushed by the hydraulic oil, since the movable piston part (209) is slidably connected with the piston rod (203), the piston rod (203) and the fixed piston part (210) are in a static state, the movable piston part (209) first compresses the space of the second cavity (206), and part of the hydraulic oil in the second cavity (206) is first discharged from the second oil port (212) and the fourth oil port (214); When the movable piston part (209) slides to the limit position, the limiting part (216) abuts against one side of the sliding guide groove (215) close to the movable piston part (209), the third oil port (213) is closed, the hydraulic oil enters the first cavity (205) from the first oil port (211), and the fixed piston part (210) and the piston rod (203) are moved, at this time, the hydraulic oil exists between the fixed piston part (210) and the movable piston part (209), since the hydraulic oil in the second cavity (206) is reduced and is discharged through the second oil port (212) and the fourth oil port (214) at the same time, the injection speed is improved; When the second cavity (206) is compressed to the minimum, the third cavity (217) between the movable piston part (209) and the fixed piston part (210) is communicated with the fourth oil port (214), the fixed piston part (210) continues to move, the hydraulic oil in the third cavity (217) is discharged through the fourth oil port (214), the last action of injection is realized, and the movable piston part (209) and the fixed piston part (210) are reattached in contact; Release action: the fourth oil port (214) is kept closed, the hydraulic oil enters the second cavity (206) through the second oil port (212), and the movable piston part (209), the fixed piston part (210) and the piston rod (203) are moved to reset.

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