Double-acting multistage cylinder

Abstract

The utility model discloses a double-acting multi-stage cylinder, and belongs to the field of hydraulic oil cylinders. The hydraulic cylinder comprises a cylinder barrel, a sleeve and a first-stage piston which are matched with each other are arranged in the cylinder barrel, a piston rod and a second-stage piston which are matched with each other are arranged in the sleeve, the inner wall of the cylinder barrel, the outer wall of the sleeve and the first-stage piston jointly define a first-stage rod cavity, and the inner wall of the sleeve, the outer wall of the piston rod and the second-stage piston jointly define a second-stage rod cavity. The transverse deep hole is formed in the sleeve, one side of the transverse deep hole is connected with the oil groove, the other side of the transverse deep hole is connected with the hole, meanwhile, the step and the oil hole are formed in the position, close to the hole, of the first-stage piston, a first-stage rod cavity and a second-stage rod cavity are communicated, and communication of an oil way is achieved. The sleeve adopts a front end punching mode, so that the sleeve and the first-stage piston are made into a split type, and the machining difficulty and the manufacturing cost of the sleeve are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of hydraulic oil cylinder, concretely relates to a double-acting multistage cylinder. BACKGROUND

[0002] Hydraulic oil cylinder is the commonly used executing element in engineering machinery, in order to make the equipment parts obtain larger stroke in limited installation position, usually need to use multistage cylinder. Double-acting multistage cylinder refers to the hydraulic executing element for realizing bidirectional telescopic motion through hydraulic drive. Double-acting multistage cylinder oil circuit is complex, in order to make oil enter from one level rod cavity into two level rod cavity, usually a sandwich is designed to pass oil.

[0003] The Chinese patent document with publication date of September 16, 2015 and publication number of CN204646856U discloses a double-acting multistage oil cylinder internal sandwich oil circuit structure, comprising a cylinder body, the cylinder body is provided with a first oil passing hole and a second oil passing hole, which are respectively connected with a first oil inlet and a second oil inlet to communicate with external oil pipes, the cylinder body is internally provided with a piston rod assembly, the piston rod assembly comprises a piston and a piston rod which are fixedly connected and integrally actuated, a multistage sleeve assembly with sandwich structure is arranged between the cylinder body and the piston rod assembly, each sleeve assembly with sandwich structure comprises a cylinder bottom, a cylinder cover and an intermediate piston, a sleeve one and a sleeve two which are fixedly connected and integrally actuated, the piston and the intermediate piston are respectively sealed with the sleeve two and the cylinder body to seal the oil circuit at both ends. The utility model has the defects of complex structure, large processing and assembling difficulty. UTILITY MODEL CONTENT

[0004] The utility model aims at solving the problems of complex sandwich structure oil passing design and large processing and assembling difficulty of the prior art, and provides a double-acting multistage cylinder, which can realize the oil cylinder function while reducing the processing and assembling difficulty of the multistage cylinder and reducing the manufacturing cost of the multistage cylinder through the internal oil circuit design of the utility model.

[0005] The utility model provides a double-acting multistage cylinder, which can realize the oil cylinder function while reducing the processing and assembling difficulty of the multistage cylinder and reducing the manufacturing cost of the multistage cylinder through the internal oil circuit design of the utility model.

[0006] In the scheme, the cylinder barrel, the sleeve and the first-stage piston jointly enclose a first-stage rod cavity, and the sleeve, the piston rod and the second-stage piston jointly enclose a second-stage rod cavity. The through connection of the first-stage rod cavity and the second-stage rod cavity is realized through the transverse deep hole and the oil groove on the sleeve, the hole close to the tail end side and the step and the oil hole on the first-stage piston.

[0007] As a preferred, the cylinder barrel is provided with a first oil port and a second oil port above, the first oil port is connected with the cylinder through a first oil pipe, the second oil port is connected with the cylinder through a second oil pipe, and the first oil port and the second oil port are connected with the first-stage rod cavity and the second-stage rod cavity through the transverse deep hole and the oil groove on the sleeve, the hole close to the tail end side and the step and the oil hole on the first-stage piston.

[0008] The second oil port is connected with the cylinder through a second oil pipe.

[0009] As a preferred, the front end of the cylinder is matched with a first guide sleeve, and the front end of the sleeve is matched with a second guide sleeve.

[0010] As a preferred, the transverse deep hole extends from the front end of the sleeve to the front end of the first piston.

[0011] As a preferred, the front end of the transverse deep hole is sealed by plug welding.

[0012] As a preferred, the oil groove is arranged on the side near the front end of the inner hole of the sleeve and is connected with the transverse deep hole.

[0013] As a preferred, the hole is arranged on the side near the tail end of the sleeve, and the axis of the hole is parallel to but not coincident with the axis of the oil hole arranged on the front end of the first piston.

[0014] As a preferred, the hole arranged on the side near the tail end of the sleeve is arranged uniformly in the circumferential direction of the sleeve, and the axis of the hole is perpendicular to the axis of the transverse deep hole.

[0015] As a preferred, the second piston is positioned by a steel wire retainer ring.

[0016] As a preferred, the second piston is provided with a first sealing element.

[0017] Compared with the prior art, the beneficial effects of the utility model are as follows: the double-acting multi-stage cylinder of the utility model realizes the penetration of the oil passage by machining a transverse deep hole and an oil groove on the sleeve, arranging a hole on the side near the tail end of the sleeve, arranging a step on the hole and an oil hole to connect the first rod cavity and the second rod cavity, and adopting the mode of punching the hole on the front end of the sleeve, so that the sleeve and the first piston can be made into a split structure, and the machining difficulty and manufacturing cost of the sleeve are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the overall structure schematic diagram of the double-acting multi-stage cylinder of the utility model.

[0019] Figure 2 is Figure 1 is the local enlarged view of A in figure.

[0020] Figure 3 is the structure schematic diagram of the double-acting multi-stage cylinder when the piston rod of the utility model is stretched out.

[0021] Figure 4 is the structure schematic diagram of the double-acting multi-stage cylinder when the piston rod of the utility model is retracted.

[0022] In the diagram, 1-cylinder barrel, 11-first oil port, 12-second oil port, 13-first oil pipe, 14-second oil pipe, 15-first stage rod chamber, 16-second stage rod chamber, 2-sleeve, 21-hole, 22-lateral deep hole, 23-oil groove, 3-first stage guide sleeve, 4-first stage piston, 41-oil hole, 42-first sealing ring, 5-piston rod, 43-second sealing ring, 6-second stage guide sleeve, 7-second stage piston, 71-first seal, 72-third sealing ring, 8-wire retaining ring. Detailed Implementation

[0023] Specific embodiments of the present invention will be described below. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the present invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention.

[0024] Example 1:

[0025] This embodiment 1 discloses a double-acting multi-stage cylinder mechanism, such as Figures 1 to 4 As shown.

[0026] exist Figures 1 to 4 In the illustrated embodiment 1, this utility model provides a technical solution: a double-acting multi-stage cylinder, including a cylinder barrel 1, inside which there are mutually cooperating sleeves 2 and a first-stage piston 4, inside which there are mutually cooperating piston rods 5 and second-stage pistons 7, the inner wall of the cylinder barrel 1 and the outer wall of the sleeve 2 and the first-stage piston together form a first-stage rod chamber 15, the inner wall of the sleeve 2 and the outer wall of the piston rod 5 and the second-stage piston 7 together form a second-stage rod chamber 16, the cylinder barrel 1, the sleeve 2 and the first-stage piston 4 together form a first-stage hydraulic cylinder, the sleeve 2, the second-stage piston 7 and the piston rod 5 together form a second-stage hydraulic cylinder, the sleeve 2 is provided with a transverse deep hole 22 and an oil groove 23, the sleeve 2 has a hole 21 on the side near the tail end, the first-stage piston 4 is provided with a step and an oil hole 41 near the hole 21, the extension and retraction of the hydraulic cylinder can be completed by relying on the oil and the internal structure.

[0027] In this embodiment, Figure 1 This is a schematic diagram of the overall structure of a double-acting multi-stage cylinder according to this utility model. Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle. Figure 3 This is a schematic diagram of the structure of a double-acting multi-stage cylinder piston rod during retraction according to this utility model. Figure 4 This is a schematic diagram of the structure of a double-acting multi-stage cylinder with the piston rod extended, according to this utility model. The four figures together illustrate the specific structure and working principle of the double-acting multi-stage cylinder in this embodiment.

[0028] like Figure 1As shown, the hydraulic cylinder is structured from outside to inside as follows: the cylinder barrel 1, the sleeve 2 and the first-stage piston 4 inside the cylinder barrel 1, the second-stage piston 7 and the piston rod 5 inside the sleeve 2. The cylinder barrel 1 inner wall, the sleeve 2 outer wall and the first-stage piston 4 together form a first-stage rod cavity 15, and the sleeve 2 inner wall and the piston rod 5 outer wall together form a second-stage rod cavity 16. The sleeve 2 and the first-stage piston 4 form a first-stage cylinder, and the sleeve 2, the second-stage piston 7 and the piston rod 5 form a second-stage cylinder.

[0029] As shown, the cylinder barrel 1 front end is connected with the first-stage guide sleeve 3, and the two are matched with each other. The first-stage guide sleeve 3 can facilitate the movement of the sleeve 2. The sleeve 2 front end is connected with the second-stage guide sleeve 6, and the two are matched with each other. The second-stage guide sleeve 6 can facilitate the movement of the piston rod 5. Figure 1 Further analysis of the structure, as shown, the cylinder barrel 1 upper end is provided with a first oil port and a second oil port and a cylinder barrel upper cover. The first oil port 11 is connected with the first oil pipe 13, and the second oil port 12 is connected with the second oil pipe 14. Both the oil ports can be used as oil inlet and outlet ports. When the piston rod 5 is extended, the second oil port 12 is used for oil inlet, and the oil is finally returned by the first oil port 11 through the first-stage cylinder and the second-stage cylinder. When the piston rod 5 is retracted, the first oil port 11 is used for oil inlet, and the oil is finally returned by the second oil port 12 through the first-stage cylinder and the second-stage cylinder.

[0030] Figure 1 As shown, the sleeve 2 inside the cylinder barrel 1 is provided with two transverse deep holes 22. The transverse deep holes 22 extend from the sleeve 2 front end face to the rear end, and extend to the first-stage piston 4 front end. The transverse deep holes 22 are located between the first-stage rod cavity 15 and the second-stage rod cavity 16.

[0031] As shown, the sleeve 2 inside the cylinder barrel 1 is provided with two transverse deep holes 22. The transverse deep holes 22 extend from the sleeve 2 front end face to the rear end, and extend to the first-stage piston 4 front end. The transverse deep holes 22 are located between the first-stage rod cavity 15 and the second-stage rod cavity 16. Figure 1 The following will be described in detail the internal through structure of the transverse deep hole 22, the first-stage rod cavity 15 and the second-stage rod cavity 16. As shown, the sleeve 2 inside the cylinder barrel 1 is further provided with an oil groove 23. The oil groove 23 is located at the sleeve 2 inner hole near the front end, so as to connect the transverse deep hole 22 and the second-stage rod cavity 16 formed by the sleeve 2 inner wall, the piston rod 5 outer wall and the second-stage piston 7. When the piston rod 5 is retracted, the oil is fed from the first oil port 11, and returned by the second oil port 12. The oil will enter the second-stage rod cavity 16 from the transverse deep hole 22 through the oil groove 23. When the piston rod 5 is extended, the oil is fed from the second oil port 12, and returned by the first oil port 11. The oil will enter the transverse deep hole 22 from the second-stage rod cavity 16 through the oil groove 23.

[0032] Figure 1 As shown, the sleeve 2 inside the cylinder barrel 1 is provided with two transverse deep holes 22. The transverse deep holes 22 extend from the sleeve 2 front end face to the rear end, and extend to the first-stage piston 4 front end. The transverse deep holes 22 are located between the first-stage rod cavity 15 and the second-stage rod cavity 16.

[0033] As shown, the sleeve 2 inside the cylinder barrel 1 is provided with two transverse deep holes 22. The transverse deep holes 22 extend from the sleeve 2 front end face to the rear end, and extend to the first-stage piston 4 front end. The transverse deep holes 22 are located between the first-stage rod cavity 15 and the second-stage rod cavity 16. Figure 1 ​​As shown, the sleeve 2 inside the cylinder barrel 1 is provided with a hole 21 on the side close to the tail end to communicate the transverse deep hole 22 and the first cavity rod 15 formed by the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first piston 4. When the piston rod 5 is retracted, the oil enters from the first oil port 11 and returns from the second oil port 12, and the oil will enter the transverse deep hole 22 from the first cavity rod 15 through the hole 21. When the piston rod 5 is extended, the oil enters from the first oil port 12 and returns from the second oil port 11, and the oil enters the first rod cavity 15 from the transverse deep hole 22 through the hole 21.

[0034] As shown in the drawings, Figure 1 The front end of the transverse deep hole 22 on the sleeve 2 is sealed by welding.

[0035] The sealing performance is improved to prevent oil leakage. Compared with the threaded seal, the efficiency and reliability of the seal are improved.

[0036] As shown in the drawings, Figure 1 The first piston 4 is provided with a step and four oil holes 41 close to the hole 21 on the sleeve 2 to continuously communicate the transverse deep hole 22 and the first cavity rod 15 formed by the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first piston 4 when the first guide sleeve 3 and the first piston 4 are pressed.

[0037] As shown in the drawings, Figure 1 The axis of the hole 21 on the side close to the tail end of the sleeve 2 is parallel to but not coincident with the axis of the oil hole 41 on the first piston 4.

[0038] As shown in the drawings, Figure 1 The hole 21 on the side close to the tail end of the sleeve 2 is evenly distributed along the circumference of the sleeve 2, and its axis is perpendicular to the axis of the transverse deep hole 22.

[0039] As shown in the drawings, Figure 1 The second piston 7 and the sleeve 2 are positioned by a steel wire retainer to achieve precise positioning and high reliability, and assembly and disassembly are convenient.

[0040] As shown in the drawings, Figure 2 The first piston 4 is provided with a first sealing ring 42 and a second sealing ring 43, and the second piston 7 is provided with a third sealing ring 72 and a first sealing member 71. For the higher working pressure of the second piston 7, a sealing member is used, which has stronger high-pressure adaptability and ensures the sealing performance of the entire double-acting multi-stage cylinder.

[0041] The overall structure is summarized as follows, Figure 1As shown, a double-acting multi-stage cylinder, the cylinder barrel 1, the front end of the cylinder barrel is connected with the first guide sleeve 3, and the two are matched with each other, the cylinder body 1 has a sleeve 2 and a first piston 4 matched with each other in the inside, the sleeve 2 can be conveniently moved through the first guide sleeve, the front end of the sleeve 2 is connected with the second guide sleeve 7, and the two are matched with each other, the sleeve 2 has a piston rod 5 and a second piston 7 matched with each other in the inside, the piston rod 2 can be conveniently moved through the second guide sleeve, the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first piston 4 jointly form a first rod cavity 15, the inner wall of the sleeve 2, the outer wall of the piston rod 5 and the second piston 7 jointly form a second rod cavity 16, the through hole between the first rod cavity 15 and the second rod cavity 16 is completed by the following oil way structure: a transverse deep hole 22 is arranged between the first rod cavity 15 and the second rod cavity 16, extends from the front end of the sleeve 2 to the front end of the first piston 4, an oil groove 23 is arranged in the inner hole of the sleeve 2 near the front end, so as to connect the transverse deep hole 22 with the second rod cavity 16, a hole 21 is arranged on one side of the sleeve 2 near the tail end, so as to connect the transverse deep hole 22 with the first rod cavity 15, and the step at the hole 21 and the oil hole 41 are used for continuously connecting the transverse deep hole 22 with the first rod cavity 15 when the first guide sleeve 3 and the first piston 4 are pressed. In detail, the front end of the transverse deep hole 22 arranged on the sleeve 2 adopts a sealing plug welding structure, the second piston 7 and the sleeve 2 are positioned through a steel wire retaining ring 8, the axis of the hole 21 arranged on one side of the sleeve 2 near the tail end is parallel to but not coincident with the axis of the oil hole 41 arranged on the first piston 4, the holes 21 arranged on one side of the sleeve 2 near the tail end are evenly distributed along the circumference of the sleeve 2, and the axis thereof is perpendicular to the axis of the transverse deep hole 22, the first piston 4 is provided with a first sealing ring 42 and a second sealing ring 43, and the second piston 7 is provided with a third sealing ring 72 and a first sealing member 71.

[0042] Embodiment two:

[0043] The multi-stage cylinder structure of the embodiment is the same as that of embodiment one, and the working mode of the multi-stage cylinder of the utility model in the extension process is additionally introduced in detail.

[0044] In Figures 1 to 4 As shown in the embodiment, the utility model provides a technical scheme: a double-acting multi-stage cylinder, including a cylinder barrel 1, the inside of the cylinder barrel 1 has a sleeve 2 and a first piston 4 matched with each other, the inside of the sleeve 2 has a piston rod 5 and a second piston 7 matched with each other, the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first piston jointly form a first rod cavity 15, the inner wall of the sleeve 2, the outer wall of the piston rod 5 and the second piston 7 jointly form a second rod cavity 16, the cylinder barrel 1, the sleeve 2 and the first piston 4 jointly form a first oil cylinder, the sleeve 2, the second piston 7 and the piston rod 5 jointly form a second oil cylinder, the sleeve 2 is provided with a transverse deep hole 22 and an oil groove 23, and one side of the sleeve 2 near the tail end has a hole 21, the first piston 4 is provided with a step and an oil hole 41 near the hole 21, and the extension and retraction movement of the oil cylinder can be completed by relying on oil and internal structure.

[0045] In this embodiment, Figure 1 is a schematic diagram of the overall structure of a double-acting multi-stage cylinder, Figure 2 is Figure 1 a local enlarged view of A in the figure, Figure 3 is a schematic diagram of the structure of the double-acting multi-stage cylinder when the piston rod is retracted, Figure 4 is a schematic diagram of the structure of the double-acting multi-stage cylinder when the piston rod is extended. The four figures illustrate the specific structure and working principle of the double-acting multi-stage cylinder in this embodiment.

[0046] As shown in Figure 1 , the hydraulic oil cylinder has the following structure from outside to inside: the cylinder barrel 1, the sleeve 2 and the first-stage piston 4 inside the cylinder barrel 1, the second-stage piston 7 and the piston rod 5 inside the sleeve 2. The inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first-stage piston 4 together form a first-stage rod cavity 15, and the inner wall of the sleeve 2 and the outer wall of the piston rod 5 together form a second-stage rod cavity 16. This is a two-stage oil cylinder structure, in which the first-stage oil cylinder is composed of the cylinder body 1, the sleeve 2 and the first-stage piston 4, and the second-stage oil cylinder is composed of the sleeve 2, the second-stage piston 7 and the piston rod 5.

[0047] As shown in Figure 1 , the front end of the cylinder barrel 1 is connected to the first-stage guide sleeve 3, and the two are mutually matched. The sleeve 2 can be moved conveniently through the first-stage guide sleeve 3. The front end of the sleeve 2 is connected to the second-stage guide sleeve 6, and the two are mutually matched. The piston rod 5 can be moved conveniently through the second-stage guide sleeve 6.

[0048] Further analysis of the structure shows that Figure 1 , the cylinder barrel 1 is provided with a first oil port, a second oil port and a cylinder upper cover. The first oil port 11 is connected to the first oil pipe 13, and the second oil port 12 is connected to the second oil pipe 14. Both oil ports can be used as oil inlet and outlet ports. When the piston rod 5 is extended, oil is fed into the second oil port 12, passes through the first-stage oil cylinder and the second-stage oil cylinder, and is finally returned to the first oil port 11. When the piston rod 5 is retracted, oil is fed into the first oil port 11, passes through the first-stage oil cylinder and the second-stage oil cylinder, and is finally returned to the second oil port 12.

[0049] As shown in Figure 1 , the sleeve 2 inside the cylinder barrel 1 is provided with two transverse deep holes 22. The transverse deep holes 22 extend from the front end of the sleeve 2 to the front end of the first-stage piston 4. The transverse deep holes 22 are located between the first-stage rod cavity 15 and the second-stage rod cavity 16.

[0050] The internal through structure of the transverse deep holes 22 and the first-stage rod cavity 15 and the second-stage rod cavity 16 will be described in detail below, as shown in Figure 1As shown, the sleeve 2 inside the cylinder barrel 1 is also provided with an oil groove 23, which is located at the front end of the inner hole of the sleeve 2, so as to communicate the transverse deep hole 22 and the secondary rod cavity 16 formed by the inner wall of the sleeve 2, the outer wall of the piston rod 5 and the secondary piston 7. When the piston rod 5 is retracted, the oil enters from the first oil port 11 and returns from the second oil port 12, and the oil will enter the secondary rod cavity 16 from the transverse deep hole 22 through the oil groove 23. When the piston rod 5 is extended, the oil enters from the second oil port 12 and returns from the first oil port 11, and the oil will enter the transverse deep hole 22 from the secondary rod cavity 16 through the oil groove 23.

[0051] As shown in the drawings, Figure 1 As shown, the sleeve 2 inside the cylinder barrel 1 is provided with a hole 21 located at the side close to the tail end of the sleeve 2, so as to communicate the transverse deep hole 22 and the primary rod cavity 15 formed by the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the primary piston 4. When the piston rod 5 is retracted, the oil enters from the first oil port 11 and returns from the second oil port 12, and the oil will enter the transverse deep hole 22 from the primary rod cavity 15 through the hole 21. When the piston rod 5 is extended, the oil enters from the first oil port 12 and returns from the second oil port 11, and the oil will enter the primary rod cavity 15 from the transverse deep hole 22 through the hole 21.

[0052] As shown in the drawings, Figure 1 As shown, the front end of the transverse deep hole 22 provided on the sleeve 2 adopts a sealing plug welding structure.

[0053] The sealing performance is improved, and the oil leakage is prevented. Compared with the threaded sealing, the efficiency and the sealing reliability are improved.

[0054] As shown in the drawings, Figure 1 As shown, the front end of the primary piston 4 close to the hole 21 provided on the sleeve 2 is provided with a step and four oil holes 41, which are used to continuously communicate the transverse deep hole 22 and the primary rod cavity 15 formed by the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the primary piston 4 when the primary guide sleeve 3 and the primary piston 4 are pressed.

[0055] As shown in the drawings, Figure 1 As shown, the axis of the hole 21 provided on the side close to the tail end of the sleeve 2 is parallel to but not coincident with the axis of the oil hole 41 provided on the primary piston 4.

[0056] As shown in the drawings, Figure 1 As shown, the holes 21 provided on the side close to the tail end of the sleeve 2 are uniformly distributed along the circumference of the sleeve 2, and the axes thereof are perpendicular to the axis of the transverse deep hole 22.

[0057] As shown in the drawings, Figure 1 As shown, the secondary piston 7 and the sleeve 2 are positioned by a steel wire retainer, so as to realize accurate positioning, high reliability, and convenient assembly and disassembly.

[0058] As shown in the drawings, Figure 2As shown, the primary piston 4 is provided with a first sealing ring 42 and a second sealing ring 43, and the secondary piston 7 is provided with a third sealing ring 72 and a first sealing member 71. For the higher working pressure of the secondary piston 7, the sealing member is adopted, which has stronger high-pressure adaptability and ensures the sealing of the entire double-acting multi-stage cylinder.

[0059] The overall structure is summarized as follows: Figure 1 As shown, a double-acting multi-stage cylinder comprises a cylinder barrel 1, a primary guide sleeve 3 connected to the front end of the cylinder barrel, and the two are matched with each other, the cylinder barrel 1 has a sleeve 2 and a primary piston 4 matched with each other inside, the sleeve 2 can be conveniently moved through the primary guide sleeve, the sleeve 2 is connected to a secondary guide sleeve 7 at the front end, and the two are matched with each other, the sleeve 2 has a piston rod 5 and a secondary piston 7 matched with each other inside, the piston rod 2 can be conveniently moved through the secondary guide sleeve, the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2, and the primary piston 4 together form a primary rod cavity 15, the inner wall of the sleeve 2, the outer wall of the piston rod 5, and the secondary piston 7 together form a secondary rod cavity 16, and the through connection between the primary rod cavity 15 and the secondary rod cavity 16 is completed by the following oil passage structure: a transverse deep hole 22 arranged between the primary rod cavity 15 and the secondary rod cavity 16, extending from the front end of the sleeve 2 to the front end of the primary piston 4, an oil groove 23 arranged in the inner hole of the sleeve 2 near the front end to connect the transverse deep hole 22 and the secondary rod cavity 16, a hole 21 arranged on the side of the sleeve 2 near the tail end to connect the transverse deep hole 22 and the primary rod cavity 15, and a step at the hole 21 and an oil hole 41 for continuously connecting the transverse deep hole 22 and the primary rod cavity 15 when the primary guide sleeve 3 and the primary piston 4 are pressed. In detail, the front end of the transverse deep hole 22 arranged on the sleeve 2 adopts a sealing plug welding structure, the secondary piston 7 and the sleeve 2 are positioned by a steel wire retaining ring 8, the axis of the hole 21 arranged on the side of the sleeve 2 near the tail end is parallel to but not coincident with the axis of the oil hole 41 arranged on the primary piston 4, the holes 21 arranged on the side of the sleeve 2 near the tail end are evenly distributed along the circumference of the sleeve 2, and the axes thereof are perpendicular to the axis of the transverse deep hole 22, the primary piston 4 is provided with a first sealing ring 42 and a second sealing ring 43, and the secondary piston 7 is provided with a third sealing ring 72 and a first sealing member 71.

[0060] When the piston rod 5 is extended, as shown in Figure 3As shown, the hydraulic system injects hydraulic oil into the large cavity of the oil cylinder through the second oil port 12, and as the hydraulic oil enters, the oil pressure in the large cavity continuously rises, and the oil continuously pushes the sleeve 2 and the primary piston 4 to move forward, while driving the piston rod 5 and the secondary piston 7 to extend together, realizing hydraulic transmission. In the process of moving the sleeve 2 and the primary piston 4, the hydraulic oil in the primary rod cavity 15 formed by the inner wall of the cylinder 1, the outer wall of the sleeve 2 and the primary piston 4 at this time is returned through the first oil port 11, and after the primary piston 4 and the sleeve 2 move to the end, that is, after the primary stroke is completed, the piston rod 5 and the secondary piston 7 continue to extend, and in this process, the hydraulic oil in the secondary rod cavity 16 formed by the inner wall of the sleeve 2, the piston rod 5 and the secondary piston is returned through the oil groove 23 arranged at the front end of the inner hole of the sleeve 2, the transverse deep hole 22 extending from the front end face of the sleeve 2 to the front end of the primary piston 4, and the hole 21 arranged on the side close to the tail end of the sleeve 2 and the oil hole 41 arranged on the primary piston. Finally, it is returned by the first oil port 11. The oil return process is one of the keys of the hydraulic system, which ensures the circulation of the oil in the system, maintains the necessary pressure and power source. The hydraulic oil after returning is re-stored by the pump or recycled, which ensures the improvement of efficiency.

[0061] Example three:

[0062] The multi-stage cylinder structure of the embodiment is the same as that of the first and second embodiments, and the working mode of the multi-stage cylinder of the utility model in the retraction process is specifically introduced.

[0063] In Figures 1 to 4 In the embodiment shown, the utility model provides a technical scheme: a double-acting multi-stage cylinder, comprising a cylinder 1, the cylinder 1 has a sleeve 2 and a primary piston 4 matched with each other inside, the sleeve 2 has a piston rod 5 and a secondary piston 7 matched with each other inside, the inner wall of the cylinder 1, the outer wall of the sleeve 2 and the primary piston together form a primary rod cavity 15, the inner wall of the sleeve 2, the outer wall of the piston rod 5 and the secondary piston 7 together form a secondary rod cavity 16, the cylinder 1, the sleeve 2 and the primary piston 4 together form a primary oil cylinder, the sleeve 2, the secondary piston 7 and the piston rod 5 together form a secondary oil cylinder, the sleeve 2 is provided with a transverse deep hole 22 and an oil groove 23, the side close to the tail end of the sleeve 2 has a hole 21, the primary piston 4 is provided with a step and an oil hole 41 near the hole 21, and the extension and retraction movement of the oil cylinder can be completed by relying on the oil and the internal structure.

[0064] In this embodiment, Figure 1 is a schematic diagram of the overall structure of the double-acting multi-stage cylinder of the utility model, Figure 2 is Figure 1 is a local enlarged view of A in Figure 3 is a schematic diagram of the structure of the double-acting multi-stage cylinder when the piston rod is retracted, Figure 4This is a schematic diagram of the structure of a double-acting multi-stage cylinder with the piston rod extended, according to this utility model. The four figures together illustrate the specific structure and working principle of the double-acting multi-stage cylinder in this embodiment.

[0065] like Figure 1 As shown, the hydraulic cylinder has the following structure from the outside in: Cylinder 1 contains a sleeve 2 and a first-stage piston 4, which work together. Sleeve 2 contains a second-stage piston 7 and a piston rod 5, which also work together. The inner wall of cylinder 1, the outer wall of sleeve 2, and the first-stage piston 4 together form a first-stage rod chamber 15. The inner wall of sleeve 2 and the outer wall of piston rod 5 together form a second-stage rod chamber 16. This is a two-stage hydraulic cylinder structure. The first-stage cylinder consists of cylinder 1, sleeve 2, and first-stage piston 4. The second-stage cylinder consists of sleeve 2, second-stage piston 7, and piston rod 5.

[0066] like Figure 1 As shown, the front end of cylinder 1 is connected to the first-stage guide sleeve 3, and the two cooperate with each other. The first guide sleeve 3 facilitates the movement of sleeve 2. The front end of sleeve 2 is connected to the second-stage guide sleeve 6, and the two cooperate with each other. The second-stage guide sleeve 6 facilitates the movement of piston rod 5.

[0067] Further analysis of the structure, such as Figure 1 As shown, the cylinder 1 has a first oil port, a second oil port, and a cylinder cover. The first oil port 11 is connected to the first oil pipe 13, and the second oil port 12 is connected to the second oil pipe 14. Both oil ports can be used as oil inlets and outlets. When the piston rod 5 extends, oil enters through the second oil port 12, passes through the first-stage oil cylinder and the second-stage oil cylinder, and finally returns through the first oil port 11. When the piston rod 5 retracts, oil enters through the first oil port 11, passes through the first-stage oil cylinder and the second-stage oil cylinder, and finally returns through the second oil port 12.

[0068] like Figure 1 As shown, the sleeve 2 inside the cylinder 1 has two transverse deep holes 22. The transverse deep holes 22 extend from the front end of the sleeve 2 to the front end of the first-stage piston 4. The transverse deep holes 22 are located between the first-stage rod chamber 15 and the second-stage rod chamber 16.

[0069] The following details the internal interconnection structure between the transverse deep hole 22 and the primary rod cavity 15 and the secondary rod cavity 16, as follows: Figure 1 As shown, the sleeve 2 inside the cylinder 1 is also provided with an oil groove 23. The oil groove 23 is located near the front end of the inner hole of the sleeve 2 to connect the transverse deep hole 22 and the secondary rod cavity 16 formed by the inner wall of the sleeve 2, the outer wall of the piston rod 5, and the secondary piston 7. When the piston rod 5 retracts, oil enters from the first oil port 11 and returns from the second oil port 12. The oil will enter the secondary rod cavity 16 from the transverse deep hole 22 through the oil groove 23. When the piston rod 5 extends, oil enters from the second oil port 12 and returns from the first oil port 11. The oil will then enter the transverse deep hole 22 from the secondary rod cavity 16 through the oil groove 23.

[0070] As Figure 1 shown, the sleeve 2 inside the cylinder 1 is provided with a hole 21 on the side close to the tail end to communicate the transverse deep hole 22 and the first cavity rod 15 formed by the inner wall of the cylinder 1, the outer wall of the sleeve 2 and the first piston 4. When the piston rod 5 is retracted, the oil enters from the first oil port 11 and returns from the second oil port 12. The oil will enter the transverse deep hole 22 from the first cavity rod 15 through the hole 21. When the piston rod 5 is extended, the oil enters from the first oil port 12 and returns from the second oil port 11. The oil enters the first rod cavity 15 from the transverse deep hole 22 through the hole 21.

[0071] As Figure 1 shown, the front end of the transverse deep hole 22 on the sleeve 2 is sealed by welding.

[0072] The sealing performance is improved to prevent oil leakage. Compared with the threaded seal, the efficiency and reliability of the seal are improved.

[0073] As Figure 1 shown, the first piston 4 is provided with a step and four oil holes 41 at the front end close to the hole 21 on the sleeve 2 to continuously communicate the transverse deep hole 22 and the first cavity rod 15 formed by the inner wall of the cylinder 1, the outer wall of the sleeve 2 and the first piston 4 when the first guide sleeve 3 and the first piston 4 are pressed.

[0074] As Figure 1 shown, the axis of the hole 21 on the side close to the tail end of the sleeve 2 is parallel to but not coincident with the axis of the oil hole 41 on the first piston 4.

[0075] As Figure 1 shown, the holes 21 on the side close to the tail end of the sleeve 2 are evenly distributed along the circumference of the sleeve 2, and their axes are perpendicular to the axis of the transverse deep hole 22.

[0076] As Figure 1 shown, the second piston 7 and the sleeve 2 are positioned by a steel wire retainer to achieve precise positioning and high reliability, and assembly and disassembly are convenient.

[0077] As Figure 2 shown, the first piston 4 is provided with a first sealing ring 42 and a second sealing ring 43, and the second piston 7 is provided with a third sealing ring 72 and a first sealing member 71. For the higher working pressure of the second piston 7, a sealing member is used, which has stronger high-pressure adaptability and ensures the sealing performance of the entire double-acting multi-stage cylinder.

[0078] The overall structure is summarized as follows: Figure 1As shown, a double-acting multi-stage cylinder, the cylinder barrel 1, the front end of the cylinder barrel is connected with the first guide sleeve 3, both cooperate with each other, the cylinder body 1 has the sleeve 2 and the first piston 4 which cooperate with each other inside, the sleeve 2 can be moved conveniently through the first guide sleeve, the front end of the sleeve 2 is connected with the second guide sleeve 7, both cooperate with each other, the sleeve 2 has the piston rod 5 and the second piston 7 which cooperate with each other inside, the piston rod 2 can be moved conveniently through the second guide sleeve, the inner wall of the cylinder barrel 1, the outer wall of the sleeve 2 and the first piston 4 jointly form the first rod cavity 15, the inner wall of the sleeve 2, the outer wall of the piston rod 5 and the second piston 7 jointly form the second rod cavity 16, the through hole between the first rod cavity 15 and the second rod cavity 16 is completed by the following oil way structure: the transverse deep hole 22 is arranged between the first rod cavity 15 and the second rod cavity 16, extends from the front end of the sleeve 2 to the front end of the first piston 4, the oil groove 23 is arranged in the inner hole of the sleeve 2 near the front end, is used for connecting the transverse deep hole 22 and the second rod cavity 16, the hole 21 is arranged on the side of the sleeve 2 near the tail end, is used for connecting the transverse deep hole 22 and the first rod cavity 15, the step at the hole 21 and the oil hole 41 are used for continuously connecting the transverse deep hole 22 and the first rod cavity 15 when the first guide sleeve 3 and the first piston 4 are pressed tightly. In detail, the front end of the transverse deep hole 22 arranged on the sleeve 2 adopts a sealing plug welding structure, the second piston 7 is positioned with the sleeve 2 through the steel wire retaining ring 8, the axis of the hole 21 arranged on the side of the sleeve 2 near the tail end is parallel to but not coincident with the axis of the oil hole 41 arranged on the first piston 4, the holes 21 arranged on the side of the sleeve 2 near the tail end are evenly distributed along the circumference of the sleeve 2, the axis of which is perpendicular to the axis of the transverse deep hole 22, the first piston 4 is provided with the first sealing ring 42 and the second sealing ring 43, and the second piston 7 is provided with the third sealing ring 72 and the first sealing member 71.

[0079] As shown, when the piston rod 5 is retracted, Figure 4 As shown, the hydraulic system injects oil through the first oil port 11, the oil sequentially passes through the oil hole 41 arranged on the first piston 4, the hole 21 arranged on the side of the sleeve 2 near the tail end, the transverse deep hole 22 extending from the front end of the sleeve 2 to the front end of the first piston 4 and the oil groove 23 arranged in the inner hole of the sleeve 2 near the front end and finally reaches the second rod cavity, the hydraulic oil drives the second piston 7 to retract, the second piston 7 drives the piston rod 5 to retract together, after the second piston 7 reaches the steel wire retaining ring 8, the second stroke retraction is completed, and the hydraulic oil in the large cavity of the oil cylinder is returned through the second oil port 12. The oil port 11 continues to inject oil, the hydraulic oil drives the first piston 4 and the second piston 7, drives the sleeve 2 and the piston rod 5 to retract together, the hydraulic oil in the large cavity of the oil cylinder is returned through the second oil port 12, and the retraction process of the entire oil cylinder is completed after the sleeve 2 reaches the bottom position of the cylinder barrel 1.

[0080] The double-acting multi-stage cylinder in the above embodiment is characterized by the internal oil passage structure design, the sleeve 2 is provided with a transverse deep hole 22 and an oil groove 23, the sleeve 2 is provided with a hole 21 near the tail end, and the first-stage piston 4 is provided with a step and an oil hole 41 near the hole 21. It is these designs that realize the through connection between the oil passages, and the machining process is simple, the assembly is simple, and the machining difficulty and manufacturing cost are reduced.

[0081] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A double acting multi-stage cylinder characterized by, The cylinder (1) has a sleeve (2) and a first piston (4) inside, the sleeve (2) has a piston rod (5) and a second piston (7) inside; The sleeve (2) is provided with a transverse deep hole (22), one side of the transverse deep hole (22) is connected with an oil groove (23), and the other side is connected with a hole (21); The first piston (4) is provided with a step and an oil hole (41) near the hole (21). The cylinder (1) is provided with a first oil port (11) and a second oil port (12) above, the first oil port (11) is connected with the cylinder (1) through a first oil pipe (13), and the second oil port (12) is connected with the cylinder (1) through a second oil pipe (14).

2. A double acting multi-stage cylinder according to claim 1, characterized in that The cylinder (1) is provided with a first guide sleeve (3) at the front end, and the sleeve (2) is provided with a second guide sleeve (6) at the front end.

3. A double acting multi-stage cylinder according to claim 1, characterized in that The transverse deep hole (22) extends from the front end of the sleeve (2) to the front end of the first piston (4).

4. A double acting multi-stage cylinder according to claim 1, characterized in that The front end of the transverse deep hole (22) adopts a plug welding sealing structure. The oil groove (23) is arranged on one side near the front end of the inner hole of the sleeve (2) and is connected with the transverse deep hole (22).

5. A double acting multi-stage cylinder according to claim 1 or 4, characterized in that The hole (21) is arranged on one side near the tail end of the sleeve, and the axis is parallel to but not coincident with the axis of the oil hole (41) arranged on the front end of the first piston (4).

6. A double acting multi-stage cylinder according to claim 1, characterized in that The hole (21) is arranged in a circumferential distribution manner along the sleeve (2), and the axis is perpendicular to the axis of the transverse deep hole (22).

7. A double acting multi-stage cylinder as claimed in claim 1, wherein, The second piston (7) is positioned by a steel wire retainer (8) and the sleeve (2).

8. A double acting multi-stage cylinder according to claim 1 or 7, characterized in that The second piston (7) is provided with a first sealing element (71).

9. A double acting multi-stage cylinder as claimed in claim 1, wherein, ​ 10. A double acting multi-stage cylinder according to claim 1 or 9, characterized in that ​

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