Compact shuttle plunger cylinder

Abstract

The utility model relates to a plunger cylinder technical field, especially a compact plunger cylinder of back and forth action, including cylinder body, plunger rod and guide sleeve, the head end of cylinder body is covered in guide sleeve, plunger rod is located in the cylinder body, and plunger rod stretches out from the guide hole of guide sleeve, its characterized by: still including piston rod, the tail end of plunger rod in cylinder body has piston hole, and the piston end of piston rod inserts piston hole, and the inner chamber of piston hole is divided into rod cavity and rodless cavity by the piston of piston end, and the opening of piston hole is covered with cylinder cover, and one piston oil cylinder is formed on plunger rod, and the rod end of piston rod is connected with the bottom end of cylinder body. The utility model has the beneficial effects that: through inlaying piston oil cylinder in plunger cylinder, the self-limiting and back and forth action of plunger cylinder are realized while not increasing the volume of plunger rod, and moreover, plunger cylinder and piston oil cylinder can work simultaneously, and plunger cylinder will not cause the decrease of thrust because of inner chamber piston oil cylinder.

Description

Technical Field

[0001] This utility model relates to the field of piston cylinder technology, and in particular to a compact piston cylinder capable of reciprocating motion. Background Technology

[0002] In many devices, such as large compact hydraulic presses, a large thrust is required by a piston cylinder with a large diameter to achieve the pressing action (e.g., rod diameter exceeding 1000mm). However, the piston cylinder can only move in one direction. Therefore, it needs to be retracted by external force or other auxiliary cylinders. If auxiliary cylinders are added, the equipment frame structure needs to be enlarged, which increases the cost.

[0003] Meanwhile, there are many forms of stroke control for piston cylinders. If an external stroke completion detection control method is used, this method may lead to equipment failure due to the failure of detection or control components. If the mechanical step structure on the cylinder body and piston rod is used to meet the automatic limit of the piston rod during the upward stroke, such as Chinese utility model patent application CN210106291U, this structure is not very suitable for cylinders with ultra-large diameters. Because a step limit is required at the tail end, the size increases and the cost increases. At the same time, the cylinder diameter and piston rod diameter of a typical piston cylinder are not much different. If a step is added to the piston rod, the cylinder body must leave space for the step movement, which will weaken the strength of the cylinder body. If the cylinder diameter is increased to meet the strength requirement, the equipment structure will be larger, which cannot be achieved for equipment with compact requirements. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the existing self-limiting and reciprocating plunger rod is not compact enough.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a compact plunger cylinder with reciprocating motion, including a cylinder body, a plunger rod and a guide sleeve. The guide sleeve covers the head end of the cylinder body, the plunger rod is located in the cylinder body, and the plunger rod extends out from the guide hole of the guide sleeve. The feature is that it also includes a piston rod. The tail end of the plunger rod located in the cylinder body has a piston hole. The piston end of the piston rod is inserted into the piston hole. The piston at the piston end divides the inner cavity of the piston hole into a rod chamber and a rodless chamber. The opening of the piston hole is covered with a cylinder cover, forming a piston cylinder on the plunger rod. The rod end of the piston rod is connected to the bottom end of the cylinder body.

[0006] In some embodiments, optionally, the specific structure for connecting the piston rod end to the bottom end of the cylinder is as follows: the tail end of the cylinder has a rod hole, the piston rod end extends out of the cylinder through the rod hole, the piston rod has a limiting step, and a tensioning assembly is fitted on the protruding part of the piston rod extending out of the cylinder. The limiting step rests against the inner side of the cylinder, and the tensioning assembly rests against the outer side of the cylinder, thereby connecting the piston rod end to the bottom end of the cylinder. The tensioning assembly includes a washer, a main nut, a pressure pin, and a pressure bolt. The washer is located between the main nut and the cylinder. The main nut is threadedly engaged with the piston rod. The main nut has a ring of evenly arranged threaded holes around its perimeter. The pressure pin is inserted into the threaded holes and the pressure bolt is screwed in. The pressure pin rests against the washer, and the pressure bolt applies an axial preload to the cylinder through the pressure pin and the washer.

[0007] In some embodiments, optionally, the cylinder has a first oil passage for oil to flow into the inner cavity of the cylinder, and the piston rod has a second oil passage and a third oil passage for oil to flow into the rod chamber and the rodless chamber, respectively.

[0008] In some embodiments, optionally, the first oil port of the first oil passage is located at the tail end of the cylinder, and the second oil port of the second oil passage and the third oil port of the third oil passage are located at the protruding part of the piston rod end.

[0009] The beneficial effects of this utility model are: by embedding a piston cylinder inside the plunger cylinder, the plunger cylinder can achieve self-limiting and reciprocating motion without increasing the volume of the plunger rod; moreover, the plunger cylinder and the piston cylinder can work simultaneously, and the plunger cylinder will not experience a decrease in thrust due to the embedding of the piston cylinder.

[0010] Meanwhile, due to the large size of the plunger rod, the piston rod also needs to withstand a large pulling force when the plunger rod is driven to retract. If only a large main nut fitted on the piston rod is used for locking, the main nut needs to be tightened with a large torque. The torque on the main nut requires special tools such as electric, hydraulic or pneumatic tools, and it is very difficult to install and remove. Without torque, it will not be able to prevent loosening. In this utility model, the preload force applied to the main nut needs to be distributed to multiple smaller pressure bolts. Since the pressure bolts are small, there is no need for electric, hydraulic or pneumatic tools, only a torque wrench is needed, which maximizes the use of available space and achieves the maximum preload force, thereby locking the piston rod in place.

[0011] Several pressure bolts and corresponding pressure pins are evenly arranged around the main thread inside the main nut body. When the pressure bolts are tightened, they apply an axial preload to the cylinder body through the pressure pins. The preload generated in this way is purely axial, so no harmful torsion or bending occurs, while the hardened washers protect the cylinder body from the high-pressure load caused by the pressure pins. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0013] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0014] Figure 2 for Figure 1 Enlarged view of point A;

[0015] In the diagram, 1. Cylinder block, 2. Piston rod, 3. Guide sleeve, 4. Piston rod, 5. Cylinder head, 6. Main nut, 7. Washer, 8. Pressure pin, 9. Pressure bolt, 10. First oil port, 11. Second oil port, 12. Third oil port, 13. Rod chamber, 14. Rodless chamber. Detailed Implementation

[0016] like Figure 1 As shown, a compact reciprocating plunger cylinder with an extra-large diameter is disclosed. The cylinder includes a cylinder body 1, a plunger rod 2, a guide sleeve 3, and a piston rod 4. The guide sleeve 3 covers the head end of the cylinder body 1. The plunger rod 2 is located inside the cylinder body 1 and extends out of the guide hole of the guide sleeve 3. The tail end of the plunger rod 2 inside the cylinder body 1 has a piston hole. The piston end of the piston rod 4 is inserted into the piston hole. The piston at the piston end divides the inner cavity of the piston hole into a rod chamber 13 and a rodless chamber 14. A cylinder cover 5 covers the opening of the piston hole, forming a piston cylinder on the plunger rod 2. The rod end of the piston rod 4 is connected to the bottom end of the cylinder body 1.

[0017] like Figure 1 and 2 As shown, the specific structure for connecting the piston rod 4 to the bottom end of the cylinder 1 is as follows: the tail end of the cylinder 1 has a rod hole, the piston rod 4 extends out of the cylinder 1 through the rod hole, the piston rod 4 has a limiting step, and a tensioning assembly is fitted on the protruding part of the piston rod 4 extending out of the cylinder 1. The limiting step rests on the inner side of the cylinder 1, and the tensioning assembly rests on the outer side of the cylinder 1, thereby connecting the piston rod 4 to the bottom end of the cylinder 1. The tensioning assembly includes a washer 7, a main nut 6, a pressure pin 8, and a pressure bolt 9. The washer 7 is located between the main nut 6 and the cylinder 1. The main nut 6 is threadedly engaged with the piston rod 4. The main nut 6 has a ring of evenly arranged threaded holes around its perimeter. The pressure pin 8 is inserted into the threaded holes and the pressure bolt 9 is screwed in. The pressure pin 8 rests on the washer 7, and the pressure bolt 9 applies an axial preload to the cylinder 1 through the pressure pin 8 and the washer 7.

[0018] The cylinder 1 has a first oil passage that supplies oil to the inner cavity of the cylinder 1, and the piston rod 4 has a second oil passage and a third oil passage that supply oil to the rod chamber 13 and the rodless chamber 14, respectively.

[0019] The first oil port 10 of the first oil circuit is located at the tail end of the cylinder 1, and the second oil port 11 of the second oil circuit and the third oil port 12 of the third oil circuit are located at the tail end of the protruding part of the piston rod 4.

[0020] The cylinder head 5 is connected to the plunger rod 2 by bolts.

[0021] When oil enters through the first oil port 10, the oil chamber of the piston cylinder body 1 is filled with oil, pushing the piston rod 2 to move to the left along the guide sleeve 3 of the piston cylinder. The piston rod 2 is a smooth rod with no protrusions on its outer circumference for limiting movement. If the first oil port 10 continues to supply oil after reaching its stroke, causing the piston rod 2 to move, the piston rod 2 will disengage from the cylinder body 1, potentially damaging the equipment and posing a significant safety hazard. At this point, the piston cylinder embedded in the piston rod 2 acts as a limiting element. When the piston rod 2 reaches its leftward stroke, the cylinder head 5 contacts the piston of the piston rod 4, at which point the piston rod 2 stops, thus limiting its movement and providing safety protection.

[0022] When the first oil port 10 and the third oil port 12 are simultaneously supplied with oil, the oil enters the oil chamber of the cylinder body 1 and the rodless chamber 14 of the piston cylinder simultaneously, pushing the plunger rod 2 to move to the left. The force-bearing cross section is the diameter cross section of the entire plunger rod 2. The thrust generated by the plunger cylinder is not reduced due to the embedded piston cylinder. Therefore, this scheme can meet the actual use requirements of the plunger cylinder for high thrust.

[0023] When the plunger rod 2 reaches the leftward stroke, oil is introduced through the second oil port 11, and the oil enters the rod chamber 13 of the piston cylinder. Since the piston rod 44 is connected to the cylinder body 1 and is fixed, the oil will push the cylinder head 5 to drive the plunger rod 2 connected to it to retract. The plunger rod 2 retracts without the need for external force or other external auxiliary cylinders, thereby realizing the reciprocating motion of the plunger cylinder.

[0024] During installation, the main nut 6 is screwed onto the piston rod 4 like a traditional nut, but without the need for torque. When the pressure bolts 9 are tightened, they push the pressure pin 8 against the washer 7, thereby locking the piston rod 4 and the cylinder body 1 of the plunger cylinder in place.

Claims

1. A compact reciprocating piston cylinder, comprising a cylinder body (1), a piston rod (2), and a guide sleeve (3), wherein the guide sleeve (3) covers the head end of the cylinder body (1), the piston rod (2) is located inside the cylinder body (1), and the piston rod (2) extends from a guide hole in the guide sleeve (3), characterized in that: It also includes a piston rod (4), the tail end of the plunger rod (2) located inside the cylinder (1) has a piston hole, the piston end of the piston rod (4) is inserted into the piston hole, the piston at the piston end divides the inner cavity of the piston hole into a rod chamber (13) and a rodless chamber (14), the opening of the piston hole is covered with a cylinder cover (5), a piston cylinder is formed on the plunger rod (2), and the rod end of the piston rod (4) is connected to the bottom end of the cylinder (1).

2. The compact reciprocating piston cylinder according to claim 1, characterized in that: The specific structure for connecting the rod end of the piston rod (4) to the bottom end of the cylinder (1) is as follows: the tail end of the cylinder (1) has a rod hole, the rod end of the piston rod (4) extends out of the cylinder (1) through the rod hole, the piston rod (4) has a limiting step, and a tensioning assembly is fitted on the protruding part of the piston rod (4) extending out of the cylinder (1). The limiting step rests on the inner side of the cylinder (1), and the tensioning assembly rests on the outer side of the cylinder (1), thereby connecting the rod end of the piston rod (4) to the bottom end of the cylinder (1). The tensioning assembly includes... Washer (7), main nut (6), pressure pin (8) and pressure bolt (9). Washer (7) is located between main nut (6) and cylinder (1). Main nut (6) is threaded to piston rod (4). Main nut (6) has a ring of evenly arranged threaded holes around its perimeter. Pressure pin (8) is inserted into the threaded holes and pressure bolt (9) is screwed in. Pressure pin (8) rests on washer (7). Pressure bolt (9) applies axial preload to cylinder (1) through pressure pin (8) and washer (7).

3. The compact reciprocating piston cylinder according to claim 1, characterized in that: The cylinder (1) has a first oil passage that supplies oil to the inner cavity of the cylinder (1), and the piston rod (4) has a second oil passage and a third oil passage that supply oil to the rod chamber (13) and the rodless chamber (14) respectively.

4. The compact reciprocating piston cylinder according to claim 3, characterized in that: The first oil port (10) of the first oil circuit is located at the tail end of the cylinder (1), and the second oil port (11) of the second oil circuit and the third oil port (12) of the third oil circuit are located at the protruding part of the piston rod (4) rod end.

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