Rotary air cylinder

Abstract

The rotary air cylinder comprises a cylinder barrel, a front cover and a rear cover, the front cover and the rear cover are arranged at the two ends of the cylinder barrel respectively, a piston and a piston rod are arranged in the cylinder barrel, the piston and the piston rod are matched to form a limiting structure, and the limiting structure is used for limiting the rotation angle of the piston rod relative to the cylinder barrel. The limiting structure further limits the axial stroke of the piston moving towards the front cover in the cylinder barrel into a first stroke and a second stroke, the limiting structure comprises a stroke adjusting piece arranged on the piston and / or the piston rod, and the stroke adjusting piece is used for adjusting the length of the first stroke. The length of the first stroke of the piston can be adjusted through the stroke adjusting piece, and then the rotation angle of the piston rod can be adjusted. In the actual production process, air cylinders with different rotation angles can be conveniently produced without changing the spiral angle of the spiral groove of the piston rod, the production cost is saved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cylinders, and in particular to a rotary cylinder. Background Art

[0002] The cylinder is a pneumatic actuator that converts the pressure energy of compressed gas into mechanical energy in pneumatic transmission. The piston rod of a traditional cylinder can generally only move in the same direction, but cannot rotate. In order to meet user needs, a rotary cylinder has appeared on the market, whose piston rod can not only achieve axial extension and retraction movement, but also circumferential rotation movement to meet the needs of special working conditions.

[0003] For example, a mechanical double-head rotary cylinder disclosed in a Chinese utility model patent (Announcement No.: CN206360958U) has a transmission shaft in the cylinder body, a spiral groove in the middle of the transmission shaft, a fixed sleeve on the outside of the spiral groove, a steel ball on the fixed sleeve, the steel ball is located in the spiral groove, a guide seat is fixed on the outside of the fixed sleeve, a slide groove is provided on the guide seat, a guide pin is provided on the cylinder body, and the guide pin is clamped in the slide groove. When the cylinder body is filled with air pressure, the air pressure drives the sealing ring seat to move. Since the guide seat is provided with a slide groove, under the limiting action of the guide pin, the guide seat can only move left and right along the slide groove in a straight line. When the guide seat moves, the fixed sleeve moves accordingly, and the steel ball rolls along the spiral groove, prompting the transmission shaft to rotate.

[0004] However, in the mechanical double-head rotary cylinder disclosed in the above prior art, the rotation angle of the transmission shaft is subject to the rotation angle of the spiral groove. This means that if cylinders with different rotation angles are to be manufactured, different spiral grooves must be machined for the transmission shaft. In addition, the machining accuracy of the spiral groove is quite high, which undoubtedly greatly increases the production cost.

[0005] Therefore, it is necessary to improve the existing technology. Summary of the invention

[0006] The object of the present invention is to provide a rotary cylinder in view of the defects and shortcomings of the prior art, which can adjust the length of the first stroke of the piston through a stroke adjusting member, thereby conveniently producing cylinders with different rotation angles.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A rotary cylinder comprises a cylinder barrel, a front cover and a rear cover respectively arranged at two ends of the cylinder barrel, a piston and a piston rod are arranged in the cylinder barrel, the piston is fixedly matched with the cylinder barrel, the piston rod movably penetrates the piston, a spiral groove is arranged on the peripheral wall of the piston rod, the spiral groove extends in an axial spiral manner along the piston rod, the piston is provided with a guide corresponding to the spiral groove, a limiting structure is formed between the piston and the piston rod, the limiting structure is used to limit the rotation angle of the piston rod relative to the cylinder barrel, and the limiting structure also limits the axial stroke of the piston running in the cylinder barrel toward the front cover to a first stroke and a second stroke; when the piston moves in the first stroke, the guide moves along the spiral groove with the piston, so that the piston rod rotates relative to the cylinder barrel; when the piston moves to the action position of the limiting structure, the piston enters the second stroke from the first stroke, and the piston drives the piston rod to move axially synchronously at this time; wherein the limiting structure comprises a stroke adjusting member arranged on the piston and / or the piston rod, and the stroke adjusting member is used to adjust the length of the first stroke.

[0008] Furthermore, the stroke adjusting member includes a retaining spring clamped on the peripheral wall of the piston rod, and the piston rod is provided with an annular groove for installing the retaining spring.

[0009] Furthermore, the stroke adjustment member also includes a limiting sleeve arranged at the front end of the piston. When the piston drives the limiting sleeve to move to abut against the retaining spring, the piston enters the second stroke.

[0010] Furthermore, the limiting sleeve has a limiting portion, and the limiting sleeve is abutted against the clamping spring through the limiting portion.

[0011] Furthermore, an annular sealing ring and a fixing sleeve for fixing the annular sealing ring are arranged between the piston and the piston rod; and a first O-ring is arranged between the fixing sleeve and the piston.

[0012] Furthermore, a limiting ring is provided at the rear end of the piston rod, and a rear anti-collision pad for limiting cooperation with the limiting ring is embedded in the rear cover.

[0013] Furthermore, a step portion is provided in the middle of the piston rod, and a front anti-collision pad for limiting cooperation with the step portion is embedded in the front cover.

[0014] Furthermore, one end of the spiral groove extends to the rear end of the piston rod, and the other end of the spiral groove extends to the middle of the piston rod.

[0015] Furthermore, the guide member is a cylindrical pin integrally provided with the piston.

[0016] Furthermore, a guide rod is provided in the cylinder, and both ends of the guide rod are fixedly connected to the front cover and the rear cover respectively, and the guide rod passes through the piston to achieve anti-rotation cooperation between the piston and the cylinder.

[0017] After adopting the above structure, the beneficial effects of the present invention are as follows: a rotary cylinder described in the present invention comprises a cylinder barrel, a front cover and a rear cover respectively arranged at the two ends of the cylinder barrel, a piston and a piston rod are arranged in the cylinder barrel, and the piston and the piston rod cooperate to form a limiting structure, the limiting structure is used to limit the rotation angle of the piston rod relative to the cylinder barrel, and the limiting structure also limits the axial stroke of the piston running in the cylinder barrel toward the front cover to a first stroke and a second stroke, the limiting structure includes a stroke adjusting member arranged on the piston and / or the piston rod, and the stroke adjusting member is used to adjust the length of the first stroke. The length of the first stroke of the piston can be adjusted by the stroke adjusting member, thereby realizing the adjustment of the rotation angle of the piston rod. In the actual production process, there is no need to change the spiral angle of the spiral groove of the piston rod, so that cylinders with different rotation angles can be easily produced, saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the specific embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a sectional view of the overall structure of the present invention; Figure 2 The present invention Figure 1 A schematic diagram of the structure at A; Figure 3 It is a cross-sectional view of the limit sleeve of the present invention. Figure 1 (The length of the limiter is L3); Figure 4 It is a cross-sectional view of the limit sleeve of the present invention. Figure 2 (The length of the limiter is L4); Figure 5 is a cross-sectional view of a first cylinder of the present invention; Figure 6 is a cross-sectional view of a second cylinder of the present invention; Figure 7 It is a side view of the piston rod of the present invention Figure 1 (The distance between the annular groove and the rear end of the piston rod is L5); Figure 8 It is a side view of the piston rod of the present invention Figure 2 (The distance between the annular groove and the rear end of the piston rod is L6); Fig. 9 is a cross-sectional view of a third cylinder of the present invention; Fig.10It is a cross-sectional view of a fourth cylinder of the present invention.

[0020] Figures 1 to 10 The bid number is: 1. Cylinder barrel; 11. Front cover; 111. First air hole; 12. Rear cover; 121. Second air hole; 13. Rear bumper pad; 14. Front bumper pad; 15. First chamber; 16. Second chamber; 2. Piston; 21. Guide; 3. Piston rod; 31. Spiral groove; 32. Annular groove; 33. Limiting ring; 34. Step portion; 4. Limiting structure; 41. Retaining spring; 42. Limiting sleeve; 421. Limiting portion; 5. Annular sealing ring; 51. Fixing sleeve; 52. First O-ring; 53. Snap ring; 6. Guide rod; 61. Guide sleeve; 62. Second O-ring; 7. Wear-resistant ring; 8. C-ring. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0022] In the description of the present invention, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0023] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, if the term "plurality" appears, the term "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly defined and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or the like, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If present, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the present invention are for illustrative purposes only and do not represent the only implementation method.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] Embodiment 1 like Figures 1 to 10As shown, a rotary cylinder comprises a cylinder barrel 1, a front cover 11 and a rear cover 12 respectively arranged at both ends of the cylinder barrel 1, a piston 2 and a piston rod 3 are arranged in the cylinder barrel 1, the piston 2 is matched with the cylinder barrel 1 to prevent rotation, the piston rod 3 movably penetrates the piston 2, the peripheral wall of the piston rod 3 is provided with a spiral groove 31, the spiral groove 31 extends spirally along the axial direction of the piston rod 3, the piston 2 is provided with a guide 21 corresponding to the spiral groove 31, the piston 2 and the piston rod 3 cooperate to form a limiting structure 4, the limiting structure 4 is used to limit the rotation angle of the piston rod 3 relative to the cylinder barrel 1, and the limiting structure The structure 4 also defines the axial stroke of the piston 2 in the cylinder 1 toward the front cover 11 as the first stroke and the second stroke; when the piston 2 moves in the first stroke, the guide 21 moves along the spiral groove 31 following the piston 2, so that the piston rod 3 rotates relative to the cylinder 1; when the piston 2 moves to the action position of the limiting structure 4, the piston 2 enters the second stroke from the first stroke, and at this time, the piston 2 drives the piston rod 3 to move axially synchronously; wherein, the limiting structure 4 includes a stroke adjustment member arranged on the piston 2 and / or the piston rod 3, and the stroke adjustment member is used to adjust the length of the first stroke. The stroke adjustment member includes a retaining spring 41 clamped on the peripheral wall of the piston rod 3. The stroke adjustment member also includes a retaining sleeve 42 arranged at the front end of the piston 2, and when the piston 2 drives the retaining sleeve 42 to move to abut against the retaining spring 41, the piston 2 enters the second stroke. The retaining sleeve 42 has a retaining portion 421, and the retaining sleeve 42 abuts against the retaining spring 41 through the retaining portion 421. A limit ring 33 is provided at the rear end of the piston rod 3, and a rear anti-collision pad 13 for limiting the limit ring 33 is embedded in the rear cover 12. A step portion 34 is provided in the middle of the piston rod 3, and a front anti-collision pad 14 for limiting the step portion 34 is embedded in the front cover 11. One end of the spiral groove 31 extends to the rear end of the piston rod 3, and the other end of the spiral groove 31 extends to the middle of the piston rod 3. The piston 2 divides the inner cavity of the cylinder 1 into a first chamber 15 and a second chamber 16. The front cover 11 is provided with a first air hole 111 communicating with the first chamber 15, and the rear cover 12 is provided with a second air hole 121 communicating with the second chamber 16.

[0029] Based on the above embodiments, the present invention aims to provide a rotary cylinder, comprising a cylinder barrel 1, a front cover 11 and a rear cover 12 respectively arranged at the two ends of the cylinder barrel 1, a piston 2 and a piston rod 3 are arranged in the cylinder barrel 1, and a limiting structure 4 is formed between the piston 2 and the piston rod 3, and the limiting structure 4 is used to limit the rotation angle of the piston rod 3 relative to the cylinder barrel 1, and the limiting structure 4 also limits the axial stroke of the piston 2 running in the cylinder barrel 1 toward the front cover 11 to a first stroke and a second stroke, and the limiting structure 4 includes a stroke adjustment member arranged on the piston 2 and / or the piston rod 3, and the stroke adjustment member is used to adjust the length of the first stroke. The length of the first stroke of the piston can be adjusted by the stroke adjustment member, thereby realizing the adjustment of the rotation angle of the piston rod 3. In the actual production process, there is no need to change the spiral angle of the spiral groove 31 of the piston rod 3, so that cylinders with different rotation angles can be produced conveniently, saving production costs.

[0030] Specifically, for ease of expression, the distance between the front end face of the rear cover 12 and the rear end face of the retaining spring 41 is defined as L, and L is a fixed value. The first stroke of the piston 2 in the cylinder 1 toward the front cover 11 is defined as L1. The first stroke L1 is specifically the displacement of the piston 2 from the state where the rear end face of the piston 2 abuts against the rear cover 12 to the state where the limit sleeve 42 abuts against the retaining spring 41. When the piston 2 is in the first stroke L1, the piston rod 3 rotates under the drive of the piston 2. The second stroke of the piston 2 in the cylinder 1 toward the front cover 11 is defined as L2. When the piston 2 is in the second stroke L2, the piston rod 3 moves axially under the drive of the piston 2, that is, the second stroke L2 of the piston 2 is equivalent to the axial stroke of the piston rod 3, specifically the displacement of the piston rod 3 from the state where the limit ring 33 abuts against the rear bumper pad 13 to the state where the step portion 34 abuts against the front bumper pad 14, and L2 is a fixed value. Figure 3 and Figure 4 As shown in the figure, the limiting sleeve 42 has a limiting portion 421 of different lengths. For the convenience of description, the following will be selected: Figure 3 The cylinder of the limiting sleeve 42 (the length of the limiting portion 421 is L3) is named as the first cylinder. Figure 5 As shown, the first stroke of the piston 2 of the first cylinder is L11; Figure 4 The cylinder of the limiting sleeve 42 (the length of the limiting portion 421 is L4) is named as the second cylinder. Figure 6 As shown, the first stroke of the piston 2 of the second cylinder is L21. For the convenience of description, the length of the piston 2 is defined as L7, and L7 is a fixed value. It can be understood that L3+L7+L11=L4+L7+L21=L. Figures 3 to 6 It can be seen that L3<L4, L11>L21, and further, the rotation angle of the piston rod 3 of the first cylinder>the rotation angle of the piston rod 3 of the second cylinder.

[0031] Working process of the cylinder: Take the cylinder used as a door pump cylinder of a bus as an example to explain. When air is taken in from the second air hole 121, the piston 2 can only move forward under the action of the guide rod 6, and the gas in the first chamber 15 is discharged from the first air hole 111. At this time, since the free end of the piston rod 3 is applied with the load force of the door, the piston rod 3 can only rotate with the cooperation of the guide 21 and the spiral groove 31. When the piston 2 moves to the point where the limit sleeve 42 abuts against the retaining spring 41, the piston 2 enters the second stroke, and the piston rod 3 overcomes the load force of the door and moves forward under the drive of the piston 2. Move until the step portion 34 of the piston rod 3 abuts against the front anti-collision pad 14, so that the external output of the piston rod 3 is to rotate first and then extend forward; when the first air hole 111 takes in air, the gas in the second chamber 16 is discharged from the second air hole 121, and the piston rod 3 moves backward under the load force of the car door until the limit ring 33 abuts against the rear anti-collision pad 13. At this time, the piston 2 moves backward under the action of the gas pressure, and the piston rod 3 rotates with the cooperation of the guide 21 and the spiral groove 31 until the piston 2 abuts against the rear cover 12, and the piston rod 3 stops rotating.

[0032] In the present embodiment, the guide member 21 is a cylindrical pin integrally provided with the piston 2. The cylindrical pin shaft is integrally processed with the piston 2, so that the rigidity of the cylindrical pin is relatively strong, and the service life of the piston 2 and the cylindrical pin is improved. In other preferred embodiments, the guide 21 may also be a steel ball. In the present embodiment, the hardness of the material of the limit sleeve 42 is greater than the hardness of the material of the piston 2, and the setting of the limit sleeve 42 is conducive to improving the service life of the piston 2. In the present embodiment, the piston rod 3 is provided with two spiral grooves 31, and they are symmetrically distributed on the peripheral wall of the piston rod 3. Correspondingly, the piston 2 is provided with two cylindrical pins. This structural design makes the driving force of the piston 2 on the piston rod 3 more uniform, and the movement of the piston rod 3 is more stable.

[0033] As another preferred embodiment of the present invention, an annular sealing ring 5 and a fixing sleeve 51 for fixing the annular sealing ring 5 are provided between the piston 2 and the piston rod 3; a first O-ring 52 is provided between the fixing sleeve 51 and the piston 2. The fixing sleeve 51 is limitedly matched with the piston 2 through a retaining ring 53. In this embodiment, Figure 1 and Figure 2 As shown, the annular seal ring 5 and the first O-ring 52 are provided to improve the airtightness between the piston 2 and the piston rod 3. The provision of the fixing sleeve 51 makes the installation of the annular seal ring 5 and the first O-ring 52 more reliable, and prevents the annular seal ring 5 and the first O-ring 52 from moving during the movement. The provision of the retaining ring 53 is used to prevent the fixing sleeve 51 from detaching from the rear end of the piston 2.

[0034] As another preferred embodiment of the present invention, a guide rod 6 is provided in the cylinder 1, and the two ends of the guide rod 6 are fixedly connected to the front cover 11 and the rear cover 12 respectively, and the guide rod 6 passes through the piston 2 to achieve the anti-rotation fit between the piston 2 and the cylinder 1. A guide sleeve 61 and a second O-ring 62 are provided between the guide rod 6 and the piston 2. A wear-resistant ring 7 and a C-ring 8 are provided between the piston 2 and the inner wall of the cylinder 1. In this embodiment, Figure 1 and Figure 2 As shown, the piston 2 is locked with the cylinder 1 by the guide rod 6. In this embodiment, two guide rods 6 are arranged between the front cover 11 and the rear cover 12, and the two guide rods 6 are symmetrically arranged, so that the piston 2 is subjected to uniform guiding force during the movement. The arrangement of the guide sleeve 61 makes the sliding of the piston 2 relative to the guide rod 6 more stable. The arrangement of the second O-ring 62 and the C-ring 8 increases the air tightness between the first chamber 15 and the second chamber 16. The arrangement of the wear-resistant ring 7 reduces the friction loss of the piston 2, which is conducive to improving the service life of the piston 2.

[0035] Embodiment 2 This embodiment provides a rotary cylinder, whose main structure and related principles are the same as those of the first embodiment, except that the stroke adjustment member includes a retaining spring 41 clamped on the peripheral wall of the piston rod 3, and the piston rod 3 is provided with an annular groove 32 for installing the retaining spring 41.

[0036] In this embodiment, if Figures 7 to 10 As shown, by adjusting the position of the annular groove 32, that is, adjusting the installation position of the retaining spring 41, the length of the first stroke of the piston 2 can be adjusted, thereby adjusting the rotation angle of the piston rod 3. Specifically, for the convenience of description, the total length of the piston 2 and the limiting sleeve 42 is positioned as L7', and the distance from the rear end of the piston rod 3 to the front end of the rear cover 12 is defined as L8 (at this time, the limiting ring 33 and the rear anti-collision pad 13 are in contact); the first stroke of the piston 2 running in the cylinder 1 toward the front cover 11 is defined as L1. The first stroke L1 is specifically the displacement of the piston 2 from the state where the rear end face of the piston 2 is in contact with the rear cover 12 to the state where the limiting sleeve 42 and the retaining spring 41 are in contact. When the piston 2 is in the first stroke, the piston 2 moves from the state where the rear end face of the piston 2 is in contact with the rear cover 12 to the state where the limiting sleeve 42 and the retaining spring 41 are in contact. In the stroke L1, the piston rod 3 rotates under the drive of the piston 2; the second stroke of the piston 2 running in the cylinder 1 toward the front cover 11 is defined as L2. When the piston 2 is in the second stroke L2, the piston rod 3 moves axially under the drive of the piston 2, that is, the second stroke L2 of the piston 2 is equivalent to the axial stroke of the piston rod 3, specifically, the displacement of the piston rod 3 from the state where the limit ring 33 abuts against the rear bumper pad 13 to the state where the step portion 34 abuts against the front bumper pad 14, and L2 is a fixed value. Figure 7 and Figure 8As shown in the figure, the piston rod 3 is provided with annular grooves 32 at different positions. For the convenience of description, the following will be selected: Figure 7 The cylinder of the piston rod 3 (the distance between the annular groove 32 and the rear end of the piston rod 3 is L5) is named as the third cylinder. Fig. 9 As shown, the first stroke of the piston 2 of the third cylinder is L31. It can be understood that L31=L5-L7'-L8. Figure 8 The cylinder of the piston rod 3 (the distance between the annular groove 32 and the rear end of the piston rod 3 is L6) is named as the fourth cylinder. Fig.10 As shown, the first stroke of the piston 2 of the fourth cylinder is L41. It can be understood that L41 = L6-L7'-L8. Figures 7 to 10 It can be seen that, if L5>L6, then L31>L41, and further, the rotation angle of the piston rod 3 of the third cylinder>the rotation angle of the piston rod 3 of the fourth cylinder.

[0037] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the present invention.

Claims

1. A rotary cylinder, comprising a cylinder barrel (1), a front cover (11) and a rear cover (12) respectively arranged at both ends of the cylinder barrel (1), a piston (2) and a piston rod (3) being arranged in the cylinder barrel (1), the piston (2) being engaged with the cylinder barrel (1) to prevent rotation, the piston rod (3) movably passing through the piston (2), a spiral groove (31) being arranged on a peripheral wall of the piston rod (3), the spiral groove (31) extending spirally along the axial direction of the piston rod (3), the piston (2) being arranged with a guide member (21) corresponding to the spiral groove (31), characterized in that: The piston (2) and the piston rod (3) cooperate to form a limiting structure (4), the limiting structure (4) being used to limit the rotation angle of the piston rod (3) relative to the cylinder barrel (1), and the limiting structure (4) also limits the axial stroke of the piston (2) running in the cylinder barrel (1) towards the front cover (11) to a first stroke and a second stroke; When the piston (2) moves in the first stroke, the guide (21) follows the piston (2) and moves along the spiral groove (31), so that the piston rod (3) rotates relative to the cylinder barrel (1); When the piston (2) moves to the action position of the limiting structure (4), the piston (2) enters the second stroke from the first stroke, and at this time the piston (2) drives the piston rod (3) to move axially synchronously; Wherein, the limiting structure (4) comprises a stroke adjusting member arranged on the piston (2) and / or the piston rod (3), and the stroke adjusting member is used to adjust the length of the first stroke.

2. A rotary cylinder according to claim 1, characterized in that: The stroke adjustment member comprises a retaining spring (41) clamped on the peripheral wall of the piston rod (3), and the piston rod (3) is provided with an annular groove (32) for mounting the retaining spring (41).

3. A rotary cylinder according to claim 2, characterized in that: The stroke adjustment member further comprises a limiting sleeve (42) arranged at the front end of the piston (2); when the piston (2) drives the limiting sleeve (42) to move until it abuts against the retaining spring (41), the piston (2) enters the second stroke.

4. A rotary cylinder according to claim 3, characterized in that: The limiting sleeve (42) has a limiting portion (421), and the limiting sleeve (42) is abutted against the clamping spring (41) via the limiting portion (421).

5. A rotary cylinder according to claim 1, characterized in that: An annular sealing ring (5) and a fixing sleeve (51) for fixing the annular sealing ring (5) are arranged between the piston (2) and the piston rod (3); and a first O-ring (52) is arranged between the fixing sleeve (51) and the piston (2).

6. A rotary cylinder according to claim 1, characterized in that: A limiting ring (33) is provided at the rear end of the piston rod (3), and a rear anti-collision pad (13) for limiting cooperation with the limiting ring (33) is embedded in the rear cover (12).

7. A rotary cylinder according to claim 1, characterized in that: A step portion (34) is provided in the middle of the piston rod (3), and a front anti-collision pad (14) for limiting cooperation with the step portion (34) is embedded in the front cover (11).

8. The rotary cylinder according to claim 1, characterized in that: One end of the spiral groove (31) extends to the rear end of the piston rod (3), and the other end of the spiral groove (31) extends to the middle of the piston rod (3).

9. A rotary cylinder according to claim 1, characterized in that: The guide member (21) is a cylindrical pin provided integrally with the piston (2).

10. A rotary cylinder according to claim 1, characterized in that: A guide rod (6) is arranged in the cylinder (1), and two ends of the guide rod (6) are respectively fixedly connected to the front cover (11) and the rear cover (12), and the guide rod (6) passes through the piston (2) to achieve anti-rotation cooperation between the piston (2) and the cylinder (1).

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