Air cylinder

Abstract

The utility model relates to the field of pneumatics, in particular to an air cylinder capable of reducing damage of gas in a buffer cavity to a sealing part, the air cylinder comprises a first channel, the buffer cavity and an exhaust cavity are communicated through the first channel, and the minimum communication area of the first channel is larger than zero, so that the buffer cavity and the exhaust cavity are communicated through the first channel all the time; part of gas in the buffer cavity is exhausted out of the air cylinder through the first channel and the exhaust cavity all the time, the pressure in the buffer cavity is reduced, and therefore the acting force of the gas in the buffer cavity on the sealing part is reduced, and damage caused by the gas in the buffer cavity to the sealing part is reduced.

Description

Technical Field

[0001] The present invention relates to the pneumatic field, and particularly to a cylinder. Background Art

[0002] In the pneumatic field, the piston head of a cylinder is driven by gas to move, thereby driving the movement of an actuator. The piston head moves to abut against a corresponding limiting component, so as to realize the movement and stop of the piston head. High-pressure gas drives the piston head to move quickly. To reduce the damage to the cylinder caused by the impact between the piston head and the limiting component, during the process of the piston head moving from fast to stop, a buffering process is required.

[0003] In the prior art, referring to the patent document with the publication number of CN202545418U, the cooperation of a sealing ring and a first channel is adopted to realize the buffering effect on the piston head, and at the same time, the reliability of the cylinder is ensured. When the piston head cooperates with the sealing ring, the piston cavity and the outside of the cylinder are sealed at the sealing ring. During the buffering process, as the piston head moves, the air pressure in the piston cavity increases, and this pressure is opposite to the direction of the pressure pushing the piston head to move, playing a buffering role on the piston head; but at the same time, this pressure also acts on the sealing ring, and too large a pressure of the high-pressure gas will cause the sealing ring to deform and be damaged. Therefore, during the buffering process, one end of the first channel communicates with the piston cavity, the other end of the first channel communicates with the outside of the cylinder, and the throttling area of the first channel is small. While ensuring the buffering effect, the pressure in the piston cavity is gradually discharged to the outside of the cylinder through the first channel, avoiding damage to the sealing ring caused by the high-pressure gas.

[0004] The flow rate of the first channel is adjusted by screwing in or out a screw. However, during use, there will be a situation where the screw is accidentally screwed to the end to close the first channel, resulting in too high a pressure in the piston cavity during the buffering stage, and the pressure damages the sealing ring. Summary of the Invention

[0005] The present invention provides a cylinder to solve the above problems:

[0006] A cylinder, which includes a cylinder body, an end cover and a piston head. The cylinder body and the end cover are in a limiting or fixed connection. The cylinder includes a piston cavity, and the piston head is located in the piston cavity. The piston head is in sliding fit with the corresponding inner wall of the cylinder body. The piston cavity includes an exhaust cavity and a buffer cavity, and the exhaust cavity is in communication with the outside of the cylinder. It is defined that in the first position, when the piston head is in the first position, the exhaust cavity and the buffer cavity are in communication; the cylinder includes a sealing part. It is defined that in the second position, when the piston head is in the second position, at least part of the sealing part is located between the piston head and the corresponding wall part of the piston cavity; the cylinder includes a first channel, and the first channel communicates the buffer cavity and the exhaust cavity, and the minimum conduction area of the first channel is greater than zero.

[0007] Such a cylinder includes a first passage that connects a buffer chamber and an exhaust chamber. The minimum cross-sectional area of the first passage is greater than zero, enabling the buffer chamber and the exhaust chamber to be always connected through the first passage. Part of the gas in the buffer chamber always discharges from the cylinder through the first passage and the exhaust chamber, reducing the pressure in the buffer chamber. Consequently, the force exerted by the gas in the buffer chamber on the sealing portion is decreased, and the damage to the sealing portion caused by the gas in the buffer chamber is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic cross-sectional view of a cylinder with the piston head in the second position according to an embodiment of the present invention;

[0009] Figure 2 Schematic cross-sectional view of a cylinder with the piston head in the first position according to an embodiment of the present invention;

[0010] Figure 3 For Figure 1 Enlarged schematic view of area A when the plug body of the cylinder in

[0011] Figure 4 Schematic cross-sectional view of a cylinder with the piston head in the second position according to another embodiment of the present invention;

[0012] Figure 5 For Figure 4 Enlarged schematic view of area A when the plug body of the cylinder in

[0013] Figure 6 Schematic cross-sectional view of a cylinder with the piston head in the second position according to still another embodiment of the present invention;

[0014] Figure 7 For Figure 6 Enlarged schematic view of area A when the plug body of the cylinder in

[0015] Reference Signs:

[0016] Cylinder block 01, end cap 02, limit groove 021, piston head 03, piston body portion 031, buffer head 032, piston chamber 04, exhaust chamber 041, buffer chamber 042, sealing portion 05, first passage 06, first branch 061, second branch 062, third branch 063, first section 0641, second section 0642, mating portion 07, plug body 08, cap portion 081, cylindrical portion 082, first part 0821, cylindrical side wall 0822, throttling gap 09, first notch 010. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] The technical solutions of the specific embodiments will be described below with reference to the accompanying drawings:

[0019] Referring to Figures 1-7 , a cylinder, the cylinder includes a cylinder block 01, an end cover 02 and a piston head 03. The cylinder block 01 and the end cover 02 are limited or fixedly connected. The cylinder includes a piston chamber 04. The piston head 03 is located in the piston chamber 04. The piston head 03 and the corresponding inner wall of the cylinder block 01 are in sliding fit. The piston head 03 includes a piston body portion 031 and a buffer head 032. It is defined that the sliding direction of the piston head 03 close to the end cover 02 is the second direction; the buffer head 032 extends from the piston body portion 031 along the second direction; the piston chamber 04 includes a buffer chamber 042 and an exhaust chamber 041. The exhaust chamber 041 is in communication with the outside of the cylinder; referring to Figure 2 , it is defined that in the first position, when the piston head 03 is in the first position, the buffer chamber 042 and the exhaust chamber 041 are in communication; the cylinder includes a sealing portion 05, referring to Figure 1 , it is defined that in the second position, when the piston head 03 is in the second position, at least part of the sealing portion 05 is located between the piston head 03 and the corresponding wall portion of the piston chamber 04. Specifically, when the piston head 03 is in the second position, at least part of the sealing portion 05 is located between the buffer head 032 and the corresponding wall portion of the piston chamber 04; more specifically, the end cover 02 includes a limiting groove 021, and the sealing portion 05 is limited in the limiting groove 021; during the process of the piston head 03 moving along the second direction, at least part of the buffer head 032 penetrates through the sealing portion 05, and the sealing portion 05 abuts against the buffer head 032 and the end cover 02 respectively, so that the buffer chamber 042 and the exhaust chamber 041 are disconnected at the sealing portion 05; before the piston body portion 031 abuts against the end cover 02, the piston head 03 continues to move along the second direction, and the air pressure in the buffer chamber 042 increases.

[0020] The cylinder includes a first channel 06. The first channel 06 communicates the buffer chamber 042 and the exhaust chamber 041, and the minimum conduction area of the first channel 06 is greater than zero.

[0021] For such a cylinder, since the cylinder includes a first channel 06, the first channel 06 communicates the buffer chamber 042 and the exhaust chamber 041, and the minimum conduction area of the first channel 06 is greater than zero, it is realized that the buffer chamber 042 and the exhaust chamber 041 are always in communication through the first channel 06, and part of the gas in the buffer chamber 042 is always discharged from the cylinder through the first channel 06 and the exhaust chamber 041, reducing the pressure in the buffer chamber 042, thereby reducing the acting force of the gas in the buffer chamber 042 on the sealing portion 05 and reducing the damage caused by the gas in the buffer chamber 042 to the sealing portion 05.

[0022] It should be noted that: The outside of the cylinder is the relative concept of the piston chamber 04. The piston chamber 04 is inside the cylinder. For example, the outside of the cylinder can be a gas source, that is, the exhaust port is connected to the gas source through a pipe.

[0023] It should be noted that: When the piston head is in the second position, the buffer chamber 042 and the exhaust chamber 041 are disconnected at the sealing part 05.

[0024] In one embodiment, referring to Figures 1-3 , the cylinder includes a plug member 08, and the cylinder block 01 or the end cap 02 is in threaded fit with the plug member 08. Specifically, the end cap 02 is in threaded fit with the plug member 08, and the first channel 06 is located in the end cap 02; at least part of the plug member 08 is located in the chamber corresponding to the first channel 06. By rotating the plug member 08 in the screwing-in or screwing-out direction, the throttling area corresponding to the first channel 06 is adjusted. It is defined that the third position is the limit position during the screwing-in process of the plug member 08; when the plug member 08 is in the third position; there is a throttling gap 09 between the plug member 08 and the wall corresponding to the first channel 06, and the conduction area corresponding to the throttling gap 09 is the smallest conduction area of the first channel 06. Thus, when the plug member 08 is in the third position, the conduction area corresponding to the throttling gap 09 between the plug member 08 and the wall corresponding to the first channel 06 is the smallest, ensuring that even if the plug member 08 is screwed into the third position, the conduction area of the first channel 06 is still greater than zero, realizing that the buffer chamber 042 and the exhaust chamber 041 are always connected through the first channel 06, avoiding the situation in the background technology where due to human misoperation, the smallest conduction area of the first channel 06 is zero, and improving the reliability of the cylinder.

[0025] It should be noted that: The limit position is the position where the plug member 08 is located when it cannot be screwed in any further in the screwing-in direction during the screwing-in process of the plug member 08; it can be that during the screwing-in process of the plug member 08, the plug member is restricted from continuing to screw in along the screwing-in direction due to being limited.

[0026] In this embodiment, the plug member 08 can be limited to the third position during the screwing-in process by means of limiting. The plug member 08 includes a cylindrical portion 082 and a cap portion 081. It is defined that the first direction is the axial direction corresponding to the cylindrical portion 082; at least a part of the cylindrical portion 082 extends from the cap portion 081 along the first direction. The cylinder block 01 or the end cover 02 includes a mating portion 07, and the inner wall of the mating portion 07 is in threaded cooperation with the cylindrical portion 082. When the plug member 08 is in the third position, one end portion of the mating portion 07 along the first direction abuts against the cap portion 081, and at least a part of the cylindrical portion 082 is located in the cavity corresponding to the first channel 06. The throttling gap 09 is located between the cylindrical portion 082 and the wall portion corresponding to the first channel 06. Thus, during the screwing-in process of the plug member 08, by the abutment of one end portion of the mating portion 07 along the first direction against the cap portion 081, the one end portion of the mating portion 07 along the first direction limits the plug member 08. The throttling gap 09 is located between the cylindrical portion 082 and the wall portion corresponding to the first channel 06, that is, when the plug member 08 rotates in the screwing-in direction to the third position, there is still a gap between the cylindrical portion 082 and the first channel 06, that is, the throttling gap 09, so that the buffer chamber 042 and the exhaust chamber 041 are always communicated through the first channel 06. That is, during the screwing-in process, even if the plug member 08 is screwed into the third position, there is still a gap between the cylindrical portion 082 and the wall corresponding to the first channel 06, and the gap communicates the exhaust chamber 041 and the buffer chamber 042. Therefore, there is no need to consider the screwing-in stroke of the plug member 08, that is, the screwing-in stroke will not cause damage to the sealing portion 05 by the gas in the buffer chamber 042. In addition, the flow rate corresponding to the minimum conduction area of the first channel 06 can be designed as the appropriate buffer flow rate corresponding to the first channel 06. In the actual application process, the operator can directly screw the plug member 08 into the position where one end portion of the mating portion 07 along the first direction abuts against the cap portion 081, without having to try and error to debug the position of the plug member 08, and the operation is more convenient.

[0027] The first channel 06 includes a first branch 061 and a second branch 062. Specifically, the first branch 061 and the second branch 062 are holes. One port corresponding to the first branch 061 is located on the wall corresponding to the exhaust cavity 041, and one port corresponding to the second branch 062 is located on the wall corresponding to the buffer cavity 042. At least a part of the first branch 061 extends in the first direction. The columnar part 082 includes a first part 0821, and the radial dimension of the first part 0821 is smaller than the aperture dimension of the corresponding hole of the first branch 061. More specifically, the circumferential wall of the first part 0821 around the axis corresponding to the plug member 08 is a complete wall part. When the plug member 08 is in the third position, the first part 0821 is located in the cavity corresponding to the first branch 061. Thus, during the process of screwing in the plug member 08, the first part 0821 can extend into the cavity corresponding to the first branch 061. The throttling gap 09 is the gap between the first part 0821 and the wall part corresponding to the first branch 061. When the plug member 08 is in the third position, the throttling gap 09 conducts the first branch 061 and the second branch 062, that is, the first channel 06 always conducts the buffer cavity 042 and the exhaust cavity 041.

[0028] In one embodiment, referring to Figure 4 and Figure 5 , the cylinder includes a plug member 08, and the cylinder block 01 or the end cover 02 is in threaded fit with the plug member 08. Specifically, the end cover 02 is in threaded fit with the plug member 08, and the first channel 06 is located in the end cover 02; at least a part of the plug member 08 is located in the cavity corresponding to the first channel 06; by rotating the plug member 08 in the screwing-in or screwing-out direction, the throttling area corresponding to the first channel 06 is adjusted. It is defined that the third position is the limit position during the process of screwing in the plug member 08; when the plug member 08 is in the third position, there is a throttling gap 09 between the plug member 08 and the wall corresponding to the first channel 06, and the conduction area corresponding to the throttling gap 09 is the smallest conduction area of the first channel 06. Thus, when the plug member 08 is in the third position, the conduction area corresponding to the throttling gap 09 between the plug member 08 and the wall corresponding to the first channel 06 is the smallest, ensuring that even if the plug member 08 is screwed into the third position, the conduction area of the first channel 06 is still greater than zero, realizing that the buffer cavity 042 and the exhaust cavity 041 are always conducted through the first channel 06, avoiding the situation in the background art where due to manual misoperation, the smallest conduction area of the first channel 06 is zero, and improving the reliability of the cylinder.

[0029] In this embodiment, the plug member 08 can be limited to the third position during the process of screwing in the plug member 08 in a limiting manner. The plug member 08 includes a cylindrical portion 082, at least a part of the cylindrical portion 082 is located in the cavity corresponding to the first channel 06. The cylindrical portion 082 includes a cylindrical side wall 0822 located on the circumferential side of the axis of the cylinder. When the plug member 08 is in the third position, the cylindrical side wall 0822 abuts against the wall portion corresponding to the first channel 06. One of the wall portion corresponding to the first channel 06 and the cylindrical side wall 0822 has a first notch 010, and there is a throttling gap 09 between the other of the wall portion corresponding to the first channel 06 and the wall corresponding to the first notch 010. Thus, during the process of screwing in the plug member 08, the wall portion corresponding to the first channel 06 limits the plug member 08 by abutting against the cylindrical side wall 0822, and there is a throttling gap 09 between the other of the wall portion corresponding to the first channel 06 and the wall corresponding to the first notch 010. That is, when the plug member 08 rotates in the screwing-in direction to the third position, the buffer cavity 042 and the exhaust cavity 041 are conducted through the first notch 010, so that the buffer cavity 042 and the exhaust cavity 041 are always conducted through the first channel 06. That is, during the screwing-in process, even if the plug member 08 is screwed into the third position, the buffer cavity 042 and the exhaust cavity 041 can still be conducted through the channel corresponding to the first notch 010. Therefore, there is no need to consider the screwing-in stroke of the plug member 08, that is, the screwing-in stroke will not cause damage to the sealing portion 05 by the gas in the buffer cavity 042. In addition, the flow rate corresponding to the minimum conduction area of the first channel 06 can be designed as the appropriate buffer flow rate corresponding to the first channel 06. In the actual application process, the operator can directly screw the plug member 08 into the position where the cylindrical side wall 0822 abuts against the wall portion corresponding to the first channel 06, without having to try and error to debug the position of the plug member 08, and the operation is more convenient.

[0030] More specifically, the first notch 010 is located on the cylindrical side wall 0822. Compared with setting the first notch 010 on the inner wall corresponding to the adjustment channel, the space inside the channel is small, the volume of the processing tool is large, and the processing is inconvenient; setting the first notch 010 on the cylindrical side wall 0822, the external space is large and the processing is more convenient. Of course, the number of the first notches 010 can be two or more to ensure the flow rate between the buffer cavity 042 and the exhaust cavity 041, and to avoid the gas in the buffer cavity 042 being discharged too slowly, which affects the pressure relief.

[0031] In one embodiment, referring to Figure 6 and Figure 7The first channel 06 includes a first branch 061 and a third branch 063. Specifically, the first branch 061 and the third branch 063 are holes respectively. A port corresponding to the first branch 061 is located on the wall corresponding to the exhaust chamber 041, and a port corresponding to the third branch 063 is located on the wall corresponding to the buffer chamber 042. The first branch 061 and the third branch 063 are connected, and the conduction area corresponding to at least a part of the first branch 061 or at least a part of the third branch 063 is the minimum conduction area of the first channel 06.

[0032] Such a cylinder is located on the wall corresponding to the buffer chamber 042 through a port corresponding to the third branch 063, the first branch 061 and the third branch 063 are connected, and the conduction area corresponding to at least a part of the first branch 061 or at least a part of the third branch 063 is the minimum conduction area of the first channel 06, and the minimum conduction area is greater than zero, so that the buffer chamber 042 and the exhaust chamber 041 are always connected through the first channel 06, avoiding the background technology that the minimum conduction area of the first channel 06 is zero due to manual misoperation, thereby improving the reliability of the cylinder.

[0033] The first branch 061 or the third branch 063 is a diameter-reducing section, which includes a first section 0641 and a second section 0642. The conduction area of the first section 0641 is smaller than the conduction area of the second section 0642, and the length of the first section 0641 is smaller than the length of the second section 0642. The conduction area corresponding to the first section 0641 is the minimum conduction area of the first channel 06. Specifically, the minimum conduction area is greater than zero, but the area is small. If the branch is made into an equal-diameter section, the machining accuracy is high and the machining is difficult. By making the channel with the minimum conduction area into a diameter-reducing section, the conduction area of the first section 0641 is smaller than the conduction area of the second section 0642, and the length of the first section 0641 is smaller than the length of the second section 0642. The conduction area corresponding to the first section 0641 is the minimum conduction area of the first channel 06, that is, the length of the first section 0641 is small, and the machining is simple.

[0034] The third branch 063 is a variable diameter section. The first channel 06 includes a second branch 062. One port of the second branch 062 is located on the corresponding wall of the buffer chamber 042. The second branch 062 can be conducted or disconnected from the first branch 061. Thus, when the first branch 061 is disconnected from the second branch 062, the flow rate of the first channel 06 is controlled by the conduction area of the first section 0641. The conduction area of the first section 0641 is greater than zero, and the corresponding conduction area of the first section 0641 is the minimum conduction area of the first channel 06, ensuring that the pressure in the buffer chamber 042 is discharged outside the cylinder through the first channel 06 and the exhaust chamber 041. When the first branch 061 is connected to the second branch 062, the flow rate of the first channel 06 is the sum of the flow rate corresponding to the first section 0641 and the flow rate of the second branch 062. The flow rate of the first channel 06 increases, and the pressure relief speed of the buffer chamber 042 can be accelerated. Thus, while ensuring the minimum pressure relief speed of the buffer chamber 042, the flow rate adjustment of the first channel 06 is also achieved.

[0035] The way that the second branch 062 is conducted and disconnected from the first branch 061 can be controlled by a plug member 08. The cylinder includes a plug member 08. The plug member 08 includes a cylindrical portion 082. The cylinder block 01 or the end cap 02 is in threaded cooperation with the cylindrical portion 082. It is defined that the first direction is the axial direction corresponding to the cylindrical portion 082. It is defined that the third position is the limit position during the screwing-in process of the plug member 08. When the plug member 08 is located at the third position, the cylindrical portion 082 abuts against the corresponding wall portion of the first channel 06, and the first branch 061 and the second branch 062 are disconnected. During the process of the plug member 08 being screwed out from the third position, the first branch 061 and the second branch 062 are conducted. Thus, by rotating the plug member 08 in the screwing-in or screwing-out direction, the flow rate adjustment between the second branch 062 and the first branch 061 is achieved.

[0036] It should be noted that: Although this specification has described the present invention in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the art can still modify, combine or equivalently replace the present invention. All technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A cylinder, the cylinder comprising a cylinder block (01), an end cover (02) and a piston head (03), the cylinder block (01) and the end cover (02) being limited or fixedly connected, the cylinder comprising a piston chamber (04), the piston head (03) being located in the piston chamber (04), the piston head (03) being slidably engaged with the corresponding inner wall of the cylinder block (01), characterized in that, The piston chamber (04) includes an exhaust chamber (041) and a buffer chamber (042). The exhaust chamber (041) is in communication with the outside of the cylinder. It is defined that in a first position, when the piston head (03) is in the first position, the exhaust chamber (041) is in communication with the buffer chamber (042); the cylinder includes a sealing portion (05). It is defined that in a second position, when the piston head (03) is in the second position, at least a part of the sealing portion (05) is located between the piston head (03) and the corresponding wall portion of the piston chamber (04); the cylinder includes a first passage (06), and the first passage (06) is in communication with the buffer chamber (042) and the exhaust chamber (041), and the minimum conduction area of the first passage (06) is greater than zero.

2. The cylinder according to claim 1, characterized in that, The cylinder includes a plug member (08), and the cylinder block (01) or the end cap (02) is in threaded cooperation with the plug member (08). It is defined that a third position is the limit position during the screwing-in process of the plug member (08); when the plug member (08) is in the third position, the first passage (06) includes a throttling gap (09), and the throttling gap (09) is located between the plug member (08) and the corresponding wall of the first passage (06), and the conduction area corresponding to the throttling gap (09) is the minimum conduction area of the first passage (06).

3. The cylinder according to claim 2, wherein, The first passage (06) includes a first branch (061) and a second branch (062). One port corresponding to the first branch (061) is located on the wall corresponding to the exhaust chamber (041), and one port corresponding to the second branch (062) is located on the wall corresponding to the buffer chamber (042). The plug member (08) includes a cylindrical portion (082). It is defined that a first direction is the axial direction of the cylindrical portion (082). The first branch (061) extends along the first direction. The cylindrical portion (082) includes a first part (0821), and the maximum radial dimension of the first part (0821) is smaller than the aperture size of the corresponding hole of the first branch (061). When the plug member (08) is in the third position, at least a part of the first part (0821) is located in the chamber corresponding to the first branch (061).

4. The cylinder according to claim 3, wherein, The plug member (08) includes a cap portion (081), and at least a part of the cylindrical portion (082) extends from the cap portion (081) along the first direction. The cylinder block (01) or the end cap (02) includes a mating portion (07), and the inner wall of the mating portion (07) is in threaded cooperation with the cylindrical portion (082). In the first direction, when the plug member (08) is in the third position, the end of the mating portion (07) abuts against the cap portion (081).

5. The cylinder according to claim 2, characterized in that, The plug member (08) includes a cylindrical portion (082), at least a part of the cylindrical portion (082) is located in the cavity corresponding to the first channel (06), the cylindrical portion (082) includes a cylindrical side wall (0822) on the circumferential side of the axis corresponding to the cylindrical portion (082). When the plug member (08) is in the third position, the cylindrical side wall (0822) abuts against the wall portion corresponding to the first channel (06). One of the wall portion corresponding to the first channel (06) and the cylindrical side wall (0822) has a first notch (010), and there is a throttling gap (09) between the other of the wall portion corresponding to the first channel (06) and the wall corresponding to the first notch (010).

6. The cylinder according to claim 5, characterized in that, The first notch (010) is located on the cylindrical side wall (0822), and / or the number of the first notches (010) is at least two.

7. The cylinder according to claim 1, characterized in that, The first channel (06) includes a first branch (061) and a third branch (063). One port corresponding to the first branch (061) is located on the wall corresponding to the exhaust cavity (041), one port corresponding to the third branch (063) is located on the wall corresponding to the buffer cavity (042), the first branch (061) and the third branch (063) are in communication, and the conduction area corresponding to at least a part of the first branch (061) or at least a part of the third branch (063) is the minimum conduction area of the first channel (06).

8. The cylinder according to claim 7, characterized in that, The first branch (061) or the third branch (063) is a variable diameter section. The variable diameter section includes a first section (0641) and a second section (0642). The conduction area of the first section (0641) is smaller than that of the second section (0642), the length of the first section (0641) is shorter than that of the second section (0642), and the conduction area corresponding to the first section (0641) is the minimum conduction area of the first channel (06).

9. The cylinder according to claim 8, characterized in that, The third branch (063) is a variable diameter section. The first channel (06) includes a second branch (062). One port of the second branch (062) is located on the wall corresponding to the buffer cavity (042), and the second branch (062) can be in communication with or disconnected from the first branch (061).

10. The cylinder according to claim 9, characterized in that, The cylinder includes a plug member (08). The plug member (08) includes a cylindrical portion (082). The cylinder block (01) or the end cover (02) is in threaded cooperation with the cylindrical portion (082). It is defined that the first direction is the axial direction corresponding to the cylindrical portion (082); it is defined that the third position is the limit position during the screwing-in process of the plug member (08). When the plug member (08) is in the third position, the cylindrical portion (082) abuts against the wall portion corresponding to the first channel (06), and the first branch (061) and the second branch (062) are disconnected. During the process of the plug member (08) being screwed out from the third position, the first branch (061) and the second branch (062) are in communication.

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