A hydraulic cylinder with easy stroke adjustment

Abstract

This invention relates to the field of hydraulic cylinder technology, specifically to a hydraulic cylinder with easily adjustable stroke. It includes a cylinder barrel with a rear cylinder head and a front cylinder head, and a piston slidably disposed inside the cylinder barrel. One end of the piston is fixedly connected to a piston rod, and the piston rod has a through groove penetrating the piston. It also includes a telescopic limiting mechanism and a one-way pressure relief valve disposed on the telescopic limiting mechanism. In this hydraulic cylinder with easily adjustable stroke, by setting a telescopic limiting mechanism inside the cylinder barrel, the stroke of the piston is limited by the change in the length of the telescopic limiting mechanism, thereby avoiding the problem of occupying external space. The telescopic limiting mechanism adjusts its own length by the change in the oil pressure inside the cylinder barrel, and during the adjustment process, only the movement of the piston rod needs to be limited, thus solving the problem that adjusting the limiting stroke of a built-in limiting mechanism is difficult.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and more specifically, to a hydraulic cylinder that is easy to adjust in terms of stroke. Background Technology

[0002] Currently, hydraulic cylinders are widely used as hydraulic actuators. The working stroke of a hydraulic cylinder piston rod is determined by the effective working length of the cylinder barrel and the piston length. Typically, the working stroke of the piston rod is the difference between the effective working length of the cylinder barrel and the piston length. Traditional hydraulic cylinders have a constant effective working length and piston length, therefore their working stroke cannot be changed.

[0003] However, in special scenarios where the piston rod does not need to extend fully (e.g., the piston rod only needs to extend two-thirds of its stroke), hydraulic cylinders are typically equipped with a limiting mechanism to restrict the piston rod's stroke and prevent it from extending completely. Current mechanical limiting mechanisms generally fall into two categories:

[0004] One type is an external limiting mechanism, which uses a double-rod hydraulic cylinder and an adjustable nut on the rear rod to adjust the forward position of the working part. Although this mechanism is more flexible in adjustment, on the one hand, the piston rod has to be very long (usually more than 3 times the length of the single rod piston); on the other hand, the rear rod usually passes through the rear cylinder head and extends into the external environment, which will occupy a certain amount of external space.

[0005] Another type is the built-in limiting mechanism, which forms a hard limit by fixing the limiting ring between the front cylinder head and the piston to limit the extension length of the piston rod. Since this hard limit is sleeved on the piston rod, when adjusting the stroke, the entire hydraulic cylinder must be disassembled and replaced with a limiting ring of a new length before the new stroke can be adjusted. Summary of the Invention

[0006] The purpose of this invention is to provide a hydraulic cylinder that facilitates stroke adjustment. By setting a telescopic limiting mechanism inside the cylinder barrel and using the oil pressure inside the cylinder barrel to adjust the piston's limiting stroke, the invention solves the problems mentioned in the background art, namely, the problem that external limiting mechanisms occupy external space and internal limiting mechanisms are difficult to adjust the limiting stroke.

[0007] To achieve the above objectives, a hydraulic cylinder with adjustable stroke includes a cylinder barrel having a rear cylinder head and a front cylinder head, and a piston slidably disposed inside the cylinder barrel. One end of the piston is fixedly connected to a piston rod, and a through groove is provided inside the piston rod.

[0008] It also includes a telescopic limiting mechanism and a one-way pressure relief valve installed on the telescopic limiting mechanism; one end of the telescopic limiting mechanism is fixedly connected to the rear cylinder head, and the movable end extends into the through groove;

[0009] When the oil pressure in the cylinder drives the one-way pressure relief valve to open, some of the oil in the cylinder enters the telescopic limit mechanism to adjust the overall length of the telescopic limit mechanism.

[0010] The telescopic limiting mechanism is used to limit the piston's stroke by its own length.

[0011] In the above technical solution, the telescopic limiting mechanism is located inside the cylinder to reduce the space occupied by the external components. Simultaneously, when the oil pressure inside the cylinder increases, the telescopic limiting mechanism can automatically move to the piston under the action of the oil pressure, thereby limiting the piston's movement.

[0012] Based on this, the movable end of the telescopic limiting mechanism is connected to a locking block, and a protrusion is provided on the inner wall of the through groove. The locking block and the protrusion are on the same movement path, and the distance between the two protrusions is less than the width of the locking block. In this way, when the locking block and the protrusion approach each other, they cannot pass each other, thus they abut against each other to limit the piston.

[0013] Furthermore, the telescopic limiting mechanism includes a piston cylinder with one end open and the other end closed. The open end of the piston cylinder is fixedly connected to the rear cylinder head, and the closed end extends into the through groove. The side wall of the rear cylinder head is provided with a through opening corresponding to the opening of the piston cylinder.

[0014] It also includes a limiting piston rod with one end slidingly disposed inside the piston cylinder and the other end penetrating through the closed end of the piston cylinder;

[0015] One end of the limiting piston rod is fixedly connected to a locking block;

[0016] The inner wall surface of the through groove near the piston end is symmetrically provided with protruding bumps that bulge inward.

[0017] The one-way pressure relief valve includes an oil delivery chamber located inside the left end of the piston cylinder and a valve ball located inside the oil delivery chamber;

[0018] The oil delivery chamber is connected to the inside of the telescopic limiting mechanism through a top opening and to the inside of the piston cylinder on one side.

[0019] The outer diameter of the valve ball is larger than the outer diameter of the top opening of the oil delivery chamber, and an elastic element is provided between the bottom of the valve ball and the bottom of the oil delivery chamber.

[0020] A driven rod is fixedly installed on the top of the valve ball. The top end of the driven rod passes through the opening at the top of the oil delivery chamber and extends to the inner wall of the through groove. A protrusion is provided on the inner wall of the through groove.

[0021] The rear cylinder head has an adjusting bolt threaded through the side wall of the rear cylinder head.

[0022] The above describes the structure of the telescopic limiting mechanism and the one-way pressure relief valve. When the one-way pressure relief valve is opened, the oil enters the piston cylinder to push the limiting piston rod to move, causing the limiting piston rod to drive the locking block to abut against the protrusion. Then, due to the one-way action of the one-way pressure relief valve, the limiting piston rod cannot be reset, and the oil is difficult to compress. Therefore, in this state, the telescopic limiting mechanism completes the limiting of the piston.

[0023] In another technical solution, a one-way valve for venting gas from the piston cylinder is provided inside the opening of the rear cylinder head.

[0024] This technical solution allows the one-way valve to prevent the limit piston rod from being pushed by the piston, thus preventing the object from being blocked during the movement of the object and causing the piston rod to continue to apply a large thrust to the object.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. In this hydraulic cylinder with easily adjustable stroke, a telescopic limiting mechanism is installed inside the cylinder barrel. The piston stroke is limited by the change in the length of the telescopic limiting mechanism, thus avoiding the problem of occupying external space. At the same time, the telescopic limiting mechanism adjusts its own length by the change in the oil pressure inside the cylinder barrel, and only the movement of the piston rod needs to be restricted during the adjustment process, thus solving the problem that it is difficult to adjust the limit stroke of the built-in limiting mechanism.

[0027] 2. In this hydraulic cylinder with easy stroke adjustment, the telescopic limit mechanism can not only limit the position of the piston, but also automatically limit the movement of the piston when the piston rod encounters resistance, reducing the distance the piston rod continues to move, thereby reducing the deformation of the item when it is squeezed and improving the integrity of the item. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a cross-sectional structural diagram of the telescopic limiting mechanism of the present invention;

[0030] Figure 3 For the present invention Figure 2 A magnified schematic diagram of the A-type reservoir structure;

[0031] Figure 4 This is a schematic diagram of the card block structure of the present invention;

[0032] Figure 5 This is a schematic diagram of one working state of the telescopic limiting mechanism of the present invention;

[0033] Figure 6This is a schematic diagram of the driven rod of the present invention;

[0034] Figure 7 This is a schematic diagram of another working state of the telescopic limiting mechanism of the present invention.

[0035] The meanings of the labels in the diagram are as follows:

[0036] 100. Cylinder barrel; 101. Rear cylinder head; 102. Front cylinder head; 103. Rear oil inlet; 104. Front oil inlet; 105. Piston; 106. Piston rod; 107. Through groove; 108. End cap; 109. Protrusion; 110. Telescopic limiting mechanism; 111. Piston barrel; 112. Limiting piston rod; 113. Locking block; 114. Oil supply chamber; 115. Valve ball; 116. Support spring; 117. Driven rod; 118. Protrusion; 120. Adjusting bolt; 130. Check valve; 200. Limiting part. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] To address the problems of external limiting mechanisms occupying external space and internal limiting mechanisms being difficult to adjust in terms of stroke, this invention provides a hydraulic cylinder with easily adjustable stroke, such as... Figure 1 As shown, the hydraulic cylinder includes a cylinder barrel 100 and cylinder heads disposed at both ends of the cylinder barrel 100. A piston 105 is slidably disposed inside the cylinder barrel 100. For ease of understanding, it is referred to as... Figure 1 Taking the cylinder barrel 100 as a reference, the rear cylinder head 101 is located at the right end of the cylinder barrel 100. A rear oil inlet 103 is provided on the top of the rear cylinder head 101, through which oil enters the right side of the piston 105, pushing the piston 105 to the left. The front cylinder head 102 is located at the left end of the cylinder barrel 100, with a front oil inlet 104 on the top. Oil enters the left side of the piston 105 through the rear oil inlet 103, pushing the piston 105 to the left. A piston rod 106 is fixedly connected to the left end of the piston 105. The left end of the piston rod 106 slides through the front cylinder head 102. The penetration area needs to be sealed (usually with a sealing assembly) to prevent oil from seeping out between the inner wall of the front oil inlet 104 and the outer circumference of the through groove 107.

[0039] The piston rod 106 has a through groove 107 inside, with the right end of the through groove 107 extending through the entire piston 105. This can also be understood as: both the piston rod 106 and the piston 105 have through grooves 107 inside, and the two through grooves 107 are interconnected. The hydraulic cylinder also includes a telescopic limiting mechanism 110 and a one-way pressure relief valve mounted on the telescopic limiting mechanism 110. The telescopic limiting mechanism 110 is fixedly connected to the side wall of the rear cylinder head 101, and the movable end of the telescopic limiting mechanism 110 extends into the through groove 107, so that the movable end of the telescopic limiting mechanism 110 is located on the movement path of the piston 105. When the oil pressure between the piston 105 and the rear cylinder head 101 drives the one-way pressure relief valve to open, some oil between the piston 105 and the rear cylinder head 101 enters the telescopic limiting mechanism 110 to adjust the overall length of the telescopic limiting mechanism 110. The telescopic limiting mechanism 110 is used to limit the stroke of the piston 105 by its own length.

[0040] Specifically, such as Figure 2 As shown, the telescopic limiting mechanism 110 includes a piston cylinder 111 that is open at the right end and closed at the left end. In some embodiments, the right end of the piston cylinder 111 is fixed to the left side of the rear cylinder head 101, and the left end extends into the through groove 107. Furthermore, the telescopic limiting mechanism 110 also includes a limiting piston rod 112 whose left end (which is a piston structure to achieve a sealed connection with the inner wall of the piston cylinder 111) is slidably disposed inside the piston cylinder 111, and whose right end penetrates through the closed end of the piston cylinder 111. Simultaneously, a locking block 113 is fixedly disposed at the left end of the limiting piston rod 112, and then... Figure 4 As shown, the inner wall surface of the through groove 107 near the piston 105 is symmetrically provided with protrusions 109 protruding inward, and the distance a1 between the two protrusions 109 is less than the width a2 of the locking block 113.

[0041] The rear cylinder head 101 has a through-hole on the side wall corresponding to the opening of the piston cylinder 111.

[0042] In practice, an end cap 108 is fixedly installed on the side wall of the piston 105 facing the rear cylinder head 101. The end cap 108 has an annular structure, and its inner diameter is the same as the inner diameter of the through groove 107. Then, the protrusion 109 is placed on the inner ring of the end cap 108. With this arrangement, the protrusion 109 can be quickly replaced by replacing the end cap 108 after it wears out.

[0043] In this way, combined Figure 2The direction of the piston 105 and the positions of the locking block 113 and the end cap 108 are such that when the piston 105 moves the end cap 108 to the left to the locking block 113, the locking block 113 will block the end cap 108 through the protrusion 109. Therefore, the piston 105 connected to the end cap 108 will also be affected. At this time, the piston 105 cannot continue to move to the left, thus limiting the piston 105.

[0044] Due to different usage scenarios, the position of the piston 105 limit needs to be adjusted accordingly. Therefore, the overall length of the telescopic limit mechanism 110 cannot be fixed, which is why the piston cylinder 111 needs to extend and retract. The above describes control via a one-way pressure relief valve; for the specific control structure and method, please refer to [reference needed]. Figure 3 .

[0045] like Figure 3 As shown, in some embodiments, the one-way pressure relief valve includes an oil delivery chamber 114 disposed inside the left end of the piston cylinder 111 and a valve ball 115 located inside the oil delivery chamber 114. The oil delivery chamber 114 communicates with the inside of the telescopic limiting mechanism 110 through a top opening and with the inside of the piston cylinder 111 on the right side. The valve ball 115 is connected to the bottom of the oil delivery chamber 114 through a support spring 116 disposed at the bottom, so that the support spring 116 presses the valve ball 115 against the top of the oil delivery chamber 114. At the same time, the outer diameter of the valve ball 115 is larger than the outer diameter of the top opening of the oil delivery chamber 114, thereby sealing the top opening of the oil delivery chamber 114.

[0046] Furthermore, a driven rod 117 is fixedly mounted on the top of the valve ball 115. The top end of the driven rod 117 passes through the opening at the top of the oil delivery chamber 114 and extends to the inner wall of the through groove 107. Simultaneously, a protrusion 118 is provided on the inner wall of the through groove 107. The protrusion 118 and the driven rod 117 are on the same axis, meaning that when the protrusion 118 and the driven rod 117 approach each other, the protrusion 118 can push the driven rod 117 downwards. Correspondingly, an adjusting bolt 120 is threadedly connected to the side wall of the rear cylinder head 101. The adjusting bolt 120 penetrates the side wall of the rear cylinder head 101 to restrict the piston 105 from moving to the side wall of the rear cylinder head 101.

[0047] In other words, by setting a telescopic limiting mechanism 110 inside the cylinder 100, the stroke of the piston 105 is limited by the change in the length of the telescopic limiting mechanism 110, thereby avoiding the problem of occupying external space. At the same time, the telescopic limiting mechanism 110 adjusts its own length by the change in the oil pressure inside the cylinder 100, and only the movement of the piston rod 106 needs to be limited during the adjustment process, thus solving the problem that it is difficult to adjust the limiting stroke of the built-in limiting mechanism.

[0048] The working principle of hydraulic cylinders will be explained in more detail below:

[0049] like Figure 5 As shown, when limiting the stroke of piston 105, oil is first introduced into region c through the rear oil inlet 103. The oil in region c pushes piston 105 to move. When piston 105 moves to the position that needs to be limited (e.g., ...), ... Figure 5 At the position of piston 105, resistance is applied at the end of piston rod 106 (i.e., position b) to limit piston 105 from moving further to the left. At this time, the oil pressure in region c begins to increase, thereby overcoming the elasticity of support spring 116 and causing valve ball 115 to move down and open the opening at the top of oil delivery chamber 114. Then, some of the oil in region c flows into piston cylinder 111 through oil delivery chamber 114 (see reference). Figure 5 (In the direction of the black arrow in the image), the hydraulically driven limit piston rod 112 moves to the right (refer to...). Figure 5 (In the direction of the white arrow in the image), the limiting piston rod 112 drives the locking block 113 to abut against the side wall of the protrusion 109. When the pressure in region c is balanced with the pressure in the piston cylinder 111, the valve ball 115 at the top of the support spring 116 resets. At this time, the inner wall of the piston cylinder 111 is not connected to region c. In this way, since the oil in the piston cylinder 111 cannot be discharged, the overall length between the limiting piston rod 112 and the piston cylinder 111 is fixed.

[0050] After adjustment, whenever piston 105 moves to Figure 5 When the piston is in the middle position, the piston 105 will be blocked by the stop block 113, thus preventing the piston 105 from moving further.

[0051] When piston 105 does not need to be limited, refer to Figure 6 As shown, by turning the adjusting bolt 120, the adjusting bolt 120 is moved to the right, at which point it engages with... Figure 2 As shown, after the front cylinder head 102 is turned, the distance d between the end cap 108 and the rear cylinder head 101 becomes smaller. This means that the piston 105 can move further to the left. During the leftward movement, the protrusion 118 moves to the bottom of the driven rod 117. At this time, the driven rod 117 drives the valve ball 115 to move down and open the oil supply chamber 114. Then, the limiting piston rod 112 is pushed to the left by an external tool (such as a push rod), and the limiting piston rod 112 can be reset.

[0052] Furthermore, in order to improve the efficiency of reset, a reset spring can be provided at position e. One end of the reset spring is connected to the limiting piston rod 112, and the other end is connected to the inside of the piston cylinder 111, which is used to push the limiting piston rod 112 to move to the left.

[0053] When you need to exit Figure 6In the indicated state, the limiting piston rod 112 can be pushed to the left using an external tool to prevent it from displacing to the left. When the oil enters the cylinder 100 through the rear oil inlet 103, since the limiting piston rod 112 cannot move, the oil in the telescopic limiting mechanism 110 will only push the piston 105 to the left. At this time, the protrusion 118 disengages from the driven rod 117, and the valve ball 115 at the top of the support spring 116 resets. Alternatively, the limiting piston rod 112 can be left unobstructed, and the piston 105 can be moved to the left directly using the oil.

[0054] Moreover, the hydraulic cylinder of the present invention not only has a stroke adjustment function, but also a protection function.

[0055] like Figure 7 As shown, when the piston rod 106 is used to push an object, assuming the square object at the top is in a normal state, the piston rod 106 will push the normal object a distance d1 to the side wall of the limiting part 200; the square object at the bottom is in an abnormal state, and the abnormal object will be pushed a distance d2 to the side wall of the limiting part 200. It can be observed that the distance d2 does not reach the set distance of the piston rod 106, at which point the piston rod 106 will continue to extend, thereby crushing the abnormal object.

[0056] When the hydraulic cylinder of this invention faces this scenario, the abnormal object provides resistance to the movement of the piston rod 106, thereby increasing the oil pressure in region c. At this time, some of the oil in region c flows into the piston cylinder 111 through the oil delivery chamber 114, which is a pressure relief operation, reducing the pressure on the object. Then, the oil drives the limiting piston rod 112 to move to the right. The limiting piston rod 112 drives the locking block 113 to abut against the side wall of the protrusion 109, thereby limiting the piston 105 and preventing the piston 105 from moving further to the left. During this process, the abnormal object will only experience slight compression deformation, not large compression deformation.

[0057] To improve the limiting effect, in some embodiments, a one-way valve 130 can be installed inside the port of the rear cylinder head 101. This way, the gas inside the piston cylinder 111 can only be discharged through the one-way valve 130. Therefore, after the limiting piston rod 112 moves to the right, it cannot move to the left, thereby further improving the stability of the locking block 113 in limiting the piston 105. Furthermore, the one-way valve 130 is threadedly connected to the port to facilitate disassembly of the one-way valve 130.

[0058] In summary, the telescopic limiting mechanism 110 can not only limit the position of the piston 105, but also automatically restrict the movement of the piston 105 when the piston rod 106 encounters resistance, reducing the distance that the piston rod 106 continues to move, thereby reducing the deformation of the item when it is squeezed and improving the integrity of the item.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic cylinder with adjustable stroke, comprising a cylinder barrel (100) having a rear cylinder head (101) and a front cylinder head (102) and a piston (105) slidably disposed inside the cylinder barrel (100), wherein one end of the piston (105) is fixedly connected to a piston rod (106), characterized in that: The piston rod (106) has a through groove (107) that penetrates the piston (105). It also includes a telescopic limiting mechanism (110) and a one-way pressure relief valve disposed on the telescopic limiting mechanism (110); one end of the telescopic limiting mechanism (110) is fixedly connected to the rear cylinder head (101), and the movable end extends into the through groove (107); When the oil pressure in the cylinder (100) drives the one-way pressure relief valve to open, part of the oil in the cylinder (100) enters the telescopic limit mechanism (110) to adjust the overall length of the telescopic limit mechanism (110). The telescopic limiting mechanism (110) is used to limit the stroke of the piston (105) by its own length; The telescopic limiting mechanism (110) includes a piston cylinder (111) with one end open and the other end closed. The open end of the piston cylinder (111) is fixedly connected to the rear cylinder head, and the closed end extends into the through groove (107). The side wall of the rear cylinder head (101) is provided with a through opening corresponding to the opening of the piston cylinder (111). It also includes a limiting piston rod (112) with one end slidably disposed inside the piston cylinder (111) and the other end passing through the closed end of the piston cylinder (111). The one-way pressure relief valve includes an oil delivery chamber (114) located inside the left end of the piston cylinder (111) and a valve ball (115) located inside the oil delivery chamber (114). The oil delivery chamber (114) is connected to the inside of the telescopic limiting mechanism (110) through the top opening and to the inside of the piston cylinder (111) on one side; The outer diameter of the valve ball (115) is larger than the outer diameter of the top opening of the oil delivery chamber (114), and an elastic element is provided between the bottom of the valve ball (115) and the bottom of the oil delivery chamber (114). A driven rod (117) is fixedly provided on the top of the valve ball (115). The top end of the driven rod (117) passes through the opening at the top of the oil delivery chamber (114) and extends to the inner wall of the through groove (107). A protrusion (118) is provided on the inner wall of the through groove (107). The rear cylinder head (101) has an adjusting bolt (120) threaded through the side wall of the rear cylinder head (101).

2. The hydraulic cylinder with easily adjustable stroke according to claim 1, characterized in that: The movable end of the telescopic limiting mechanism (110) is connected to a locking block (113), and a protrusion (109) is provided on the inner wall of the through groove (107). The locking block (113) and the protrusion (109) are on the same movement path. When the locking block (113) and the protrusion (109) approach each other, they abut against each other.

3. The hydraulic cylinder with easily adjustable stroke according to claim 2, characterized in that: One end of the limiting piston rod (112) is fixedly connected to the locking block (113); The through groove (107) has symmetrically arranged protruding protrusions (109) on the inner wall surface near the piston (105).

4. The hydraulic cylinder with easily adjustable stroke according to claim 3, characterized in that: The distance between the two protrusions (109) is less than the width of the card block (113).

5. The hydraulic cylinder with easily adjustable stroke according to claim 1, characterized in that: The elastic element is a support spring (116).

6. The hydraulic cylinder with easily adjustable stroke according to claim 1, characterized in that: The protrusion (118) and the driven rod (117) are on the same axis.

7. The hydraulic cylinder with easily adjustable stroke according to claim 3, characterized in that: The rear cylinder head (101) is provided with a one-way valve (130) inside the opening for venting gas from the piston cylinder (111).

8. The hydraulic cylinder with easily adjustable stroke according to claim 7, characterized in that: The one-way valve (130) is threadedly connected to the port.

Images