Two-stage cylinder

Abstract

To provide a two-stage cylinder having a configuration which is less likely to damage even after a long use, the two-stage cylinder (which is an energy-saving type air cylinder) suppressing an air consumption in the midway of a stroke by outputting a full power only at the end of the stroke during caulking processing, press-in processing or the like.SOLUTION: A two-stage cylinder 10 composed of a first cylinder 20 which is a cylinder with a smaller cylinder diameter and a second cylinder 30 with a larger cylinder diameter, includes: a piston rod 35 installed in a slidable manner inside the first cylinder 20; a promotion connector 40 connected to a rod of the piston rod 35 installed in the first cylinder 20 and installed in a slidable manner inside the second cylinder 30; a pressure increasing piston 50 in which the promotion connector 40 is fixed at an upper recess part (first cylinder 20 side) and installed in a slidable manner inside the second cylinder 30; and a pressure increasing rod 60.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a two-stage air cylinder that outputs full power only at the end of the stroke to increase pressure when performing crimping, press-fitting, etc., thereby reducing air consumption during the stroke. [Background technology]

[0002] In processes such as crimping, press-fitting, clamping, stamping, and welding guns, a two-stage cylinder with a two-stage structure consisting of a large diameter side and a small diameter side is used, which operates with low thrust during the stroke and maximum thrust only at the end of the stroke, thereby reducing air consumption.

[0003] In a two-stage cylinder, when the piston rod on the smaller cylinder diameter side slides, the piston rod pushes the fastening parts (which fasten the smaller cylinder diameter side and the larger cylinder diameter side), and the fastening parts pushed by the piston rod on the smaller cylinder diameter side move toward the piston rod on the larger cylinder diameter side, and then the piston rod on the larger cylinder diameter side and the fastening parts are joined together (for example, by a structure in which a steel ball fits into an R groove due to the elasticity of the steel ball receiver).This structure had the disadvantage of being prone to breakage after repeated use over many years (due to deterioration and wear of the fastening parts over many years of use).

[0004] Patent Document 1 discloses a two-stage cylinder (Patent Document 1: Claims) characterized in that "a piston is slidably inserted into a first cylinder having a lid fixed to one end of a tube and a guide fixed to the other end, a second cylinder is fixed to the piston and inserted into a hole in the guide, a second piston with a piston rod fixed thereto is slidably inserted into the second cylinder, supply and discharge pipes communicating with each chamber divided by the piston in the first cylinder are connected from the outer periphery, and a supply and discharge pipe is connected to one of the chambers divided by the piston of the second cylinder from the outer periphery, and a supply and discharge pipe aligned with the operating direction of the first cylinder and inserted into the lid is connected to the other chamber." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 48-42248 Summary of the Invention [Problem to be solved by the invention]

[0006] The two-stage cylinder in Patent Document 1 (Patent Document 1: Title of the Invention) relates to a two-stage cylinder, and whereas previously each stage simply moved in sequence, this allows each stage to operate independently. It is true that each stage can move independently. However, only pressure corresponding to the pressure-receiving area of ​​the second cylinder can be transmitted to the piston rod. Therefore, it seems that full power cannot be output only at the end of the stroke.

[0007] The object of the present invention is to provide a two-stage cylinder (an energy-saving air cylinder) that outputs full power only at the end of the stroke when performing crimping, press-fitting, etc., and reduces air consumption midway through the stroke, and that has a structure that is resistant to breakage even after years of use. [Means for solving the problem]

[0008] In order to solve the above problems, the invention described in claim 1 is a two-stage cylinder having a two-stage structure with a cylinder with a smaller cylinder diameter and a cylinder with a larger cylinder diameter, comprising a first cylinder that is the cylinder with the smaller cylinder diameter and a second cylinder that is the cylinder with the larger cylinder diameter, a piston rod installed slidably inside the first cylinder, a thrust connector connected to the rod side of the piston rod installed in the first cylinder and installed slidably inside the second cylinder, a booster piston installed slidably inside the second cylinder with the thrust connector fixed to an upper (first cylinder side) recess, and a booster rod. Note that the driving force during operation of the two-stage cylinder is two types of driving force: the sliding of the thrust connector and thrust piston due to operation of the first cylinder (hydraulic cylinder) (during fast forward), and the sliding of the booster piston due to injection or discharge of air from an air adjustment port installed in the second cylinder (due to air pressure: when pressurized).

[0009] The invention described in claim 2 is a two-stage cylinder having a two-stage structure with a side with a larger cylinder diameter and a side with a smaller cylinder diameter, comprising a first cylinder which is the cylinder with the smaller cylinder diameter and a second cylinder which is the cylinder with the larger cylinder diameter, characterized in that the two-stage cylinder comprises a piston rod installed slidably inside the first cylinder, a propulsion piston connected to the rod side of the piston rod installed in the first cylinder and installed slidably inside the second cylinder, and a booster piston and booster rod installed slidably inside the second cylinder at a position facing the propulsion piston.

[0010] The invention described in claim 3 is the two-stage cylinder according to claim 2, characterized in that an insertion hole is provided on the upper surface of the second cylinder, the propulsion piston passes through the insertion hole from the upper surface of the propulsion piston, and an air adjustment pipe is installed that reaches the underside of the propulsion piston. Note that the air adjustment pipe is installed in place of the air adjustment port installed at the top of the second cylinder when the propulsion piston installed in the second cylinder slides (inside the second cylinder) (when pressurized). Note that in this specification, a cylinder is defined as a cylindrical part, a piston is defined as a part that slides (moves by sliding) inside the cylinder, a rod is defined as a rod-shaped member (integrated with the piston) that is perpendicular to the cylinder diameter direction, and a piston rod is defined as a member combining a piston and a rod. [Effects of the Invention]

[0011] The present invention is a two-stage cylinder with a two-stage structure, one with a larger cylinder diameter and one with a smaller cylinder diameter, to obtain a mechanism for outputting full power at the end of the stroke. It is equipped with a piston rod slidably installed inside the first cylinder, a thrust connector connected to the rod side of the piston rod installed in the first cylinder and slidably installed inside the second cylinder, a booster piston and booster rod slidably installed inside the second cylinder, with the thrust connector fixed to the upper (first cylinder side) recess (fastened type).

[0012] A distinctive feature is that the thrust connector is fastened (fixed) to a recess on the upper side (first cylinder side) of the booster piston, i.e., a fastening structure that uses a method of attaching and detaching fastening parts is eliminated. In short, there is no fastening mechanism for fastening the thrust connector, which is installed slidably inside the second cylinder, to the booster piston, i.e., there is no attachment and detachment mechanism, and the booster piston is installed slidably inside the second cylinder while the thrust connector remains fastened (fixed), thereby increasing the pressure-receiving area (first cylinder diameter < second cylinder diameter), and providing a mechanism that outputs full power at the end of the stroke (fastened type).

[0013] On the other hand, it is equipped with a propulsion piston connected to the rod side of the piston rod installed in the first cylinder and slidably installed inside the second cylinder, and a booster piston and booster rod installed slidably inside the second cylinder at a position facing the propulsion piston (non-fastening type).

[0014] Characteristically, there is no fastening mechanism for fastening the propulsion piston, which is installed slidably inside the second cylinder, to the booster piston (installed in a position opposite the propulsion piston), and the booster piston is installed in a so-called non-fastened state, with only surface contact, thereby increasing the pressure-receiving area (first cylinder diameter < second cylinder diameter), and providing a mechanism for outputting full power at the end of the stroke (non-fastening type).

[0015] Furthermore, instead of an air adjustment port installed at the top of the second cylinder, an insertion hole is provided on the upper surface of the second cylinder, the propulsion piston is passed through the insertion hole from its upper surface, and an air adjustment pipe is installed that reaches the underside of the propulsion piston (non-fastening type).

[0016] The present invention (with the above configuration) provides a two-stage cylinder, an energy-saving air cylinder that outputs full power only at the end of the stroke and reduces air consumption mid-stroke. Because it lacks a propulsion connector or a mechanism for connecting and disconnecting the propulsion piston and booster piston (a mechanism for switching from a fastened state to a non-fastened state and vice versa), it is possible to provide a two-stage cylinder with a structure that is not easily damaged (by wear or deterioration), i.e., a structure that is not easily damaged (by wear or deterioration). Furthermore, by installing an air adjustment tube instead of the air adjustment port installed at the top of the second cylinder, damage caused by friction with the air adjustment port when the propulsion piston reciprocates along the cylinder inner wall can be prevented, thereby reducing damage caused by wear and other factors. Another advantage of the present invention is that it achieves a two-stage cylinder that does not leak oil at all. This will be described in more detail later. [Brief explanation of the drawings]

[0017] [Figure 1] 1A and 1B are an overall view and a partially enlarged view of a two-stage cylinder (fastening type) according to the present invention; [Figure 2] FIG. 2 is an enlarged view of the fastening portion of a two-stage cylinder (fastening type). [Figure 3] FIG. 1 is a diagram for explaining the operating cycle of a two-stage cylinder (fastening type). [Figure 4] This is an overall view of a two-stage cylinder (non-fastening type). [Figure 5] This is an overall view of an improved version (with air adjustment pipe) of a two-stage cylinder (non-fastening type). [Figure 6] FIG. 1 is a diagram for explaining the operating cycle of a two-stage cylinder (non-fastening type). DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of a non-fastening two-stage cylinder according to the present invention will be described in detail with reference to Figs. 1 to 6. The two-stage cylinder 10 (fastening type) and the two-stage cylinder 11 (non-fastening type) are inventions that overcome the weakness of conventional two-stage cylinders, which were developed to obtain a mechanism for outputting full power at the end of the stroke and increasing pressure, due to the complex internal fastening structure, making them prone to breakage due to repeated use. One concept of the present invention is a "fastening type system that eliminates the internal fastening structure," and another concept is a "non-fastening system." Fig. 1(a) is an overall view of the two-stage cylinder 10 (fastening type) according to the present invention. Fig. 1(b) is an enlarged view of the α portion. Fig. 2 is an enlarged view of the fastening portion of the two-stage cylinder (fastening type).

[0019] <Two-stage cylinder structure (fastening type)> The present invention provides a two-stage cylinder 10 having a two-stage structure with a cylinder with a smaller cylinder diameter and a cylinder with a larger cylinder diameter. As shown in FIG. 1, the cylinder is composed of a first cylinder 20, which is the cylinder with the smaller cylinder diameter, and a second cylinder 30, which is the cylinder with the larger cylinder diameter. The cylinder includes a piston rod 35 slidably installed inside the first cylinder 20, a thrust connector 40 connected to the rod side of the piston rod 35 installed inside the first cylinder 20 and slidably installed inside the second cylinder 30, a booster piston 50 to which the thrust connector 40 is fixed in an upper (first cylinder 20 side) recess and which is slidably installed inside the second cylinder 30, and a booster rod 60 (output shaft) (see FIG. 1). A structural feature of the two-stage cylinder 10 (fastened type) is that the thrust connector 40 is housed in an upper (first cylinder 20 side) recess of the booster piston 50 and is fixed by bolting a thrust connector fixing member 44 (see FIG. 2).

[0020] Furthermore, a slide member 62 is provided between the outer circumferential surface of the intensifier rod 60 (on the second cylinder 30 side) and the inner surface of the end cap of the second cylinder 30, where friction occurs (with the intensifier rod 60) when the intensifier rod 60 slides (see FIGS. 1(b) and 2). It is sufficient for the slide member 62 to be provided within a range whose width (sliding direction: height) is 60% to 80% of the height of the outer circumferential surface of the intensifier rod 60 (on the second cylinder 30 side). As shown in FIG. 2, the slide member 62 may not be provided at the upper and lower ends of the outer circumferential surface of the intensifier rod 60, and the slide member 62 may be provided so that its center coincides with the center of the outer circumferential surface of the intensifier rod 60.

[0021] The slide member 62, a metal material used to reduce friction and wear during cylinder operation, is made of a copper alloy or aluminum alloy. The surface of the slide member 62 may be polished to have an uneven pattern (which absorbs lubricating oil and reduces friction). In addition to the slide member 62, a dust seal member 64 may be installed on the bottom side of the end cap (of the second cylinder 30) below the slide member 62 (as a sliding reference for crimping, press-fitting, etc.) (see FIG. 1(b)). The dust seal member 64 is a member (made of rubber or plastic) that protects the sliding parts inside the cylinder, such as the piston rod, from external dust and foreign matter. Since the intensifier rod 60 may operate in water, acidic liquids, alkaline liquids, etc., it may be made of a corrosion-resistant, chemical-resistant, acid-resistant, or alkali-resistant material, or may be subjected to a surface treatment such as plating or coating to provide corrosion-resistant, chemical-resistant, acid-resistant, or alkali-resistant properties.

[0022] <Operation cycle of two-stage cylinder (fastening type)> FIG. 3 is a diagram illustrating the operating cycle of the two-stage cylinder 10 (fastening type). As shown in FIG. 3, the operating cycle of the two-stage cylinder 10 (fastening type) is a repeated cycle of the original position stage (a) → fast-forward stage (b) → pressure stage (c) → pressure return stage (d) → original position stage (e) ((a) and (e), and (b) and (d) have the same positional relationship). The two-stage cylinder 10 (fastening type) is positioned (start positioning for crimping work, etc.) at the original position stage (a) → fast-forward stage (b), and crimping work, press-fitting work, etc. on an actual production line, etc., is performed at the pressure stage (c) → pressure return stage (d) stage (the sequence is repeated multiple times, such as pressure stage (c) → pressure return stage (d) → pressure stage (c) → pressure return stage (d)...). The operating cycle then ends at the pressure return stage (d) → original position stage (e).

[0023] <Original position stage (a)(e)> The home position stage is the starting point and the end point of the operating cycle of the two-stage cylinder 10. The positions of the piston rod 35 slidably installed inside the first cylinder 20 (the cylinder with the smaller cylinder diameter), the second cylinder 30 (the cylinder with the larger cylinder diameter), the thrust connector 40 connected to the rod side of the piston rod 35 installed inside the first cylinder 20 and slidably installed inside the second cylinder 30, the thrust connector 40 fixed to the recess on the upper side (first cylinder 20 side) and the booster piston 50 and booster rod 60 (output shaft) installed slidably inside the second cylinder 30 are as shown in Figure 3(a).

[0024] <Fast-forward stage (b)> The fast-forward stage is a stage in which the tip position of the intensifier rod 60 is fast-forwarded from its original position to a start position where crimping work, press-fitting work, etc. are actually performed on a production line, etc. (see FIG. 3(b)). The fast-forward stage causes the piston rod 35, which slides inside the first cylinder 20 (hydraulic), to slide downward. In conjunction with this movement, the intensifier piston 50 (including the thrust connector 40) and the intensifier rod 60 slide downward inside the second cylinder 30. This lowers the intensifier rod 60 from its original position to a start position where crimping work, press-fitting work, etc. are actually performed on a production line, etc. The moment the intensifier rod 60 reaches the start position, a shut-off valve linked to the first cylinder 20 is activated, and the sliding of the piston rod 35 sliding inside the first cylinder 20 stops (see FIG. 3(b)).

[0025] <Pressure stage (c) and pressure return stage (d)> The pressurizing stage and the pressurizing return stage are stages where crimping work, press-fitting work, etc. are actually performed in a production line, etc. The crimping work and press-fitting work begin with the workpiece being set so that the tip of the booster rod 60 is in contact with the workpiece (or so that the tip of the booster piston rod 70 is at a position just before contacting the workpiece) (see FIG. 3(b)).

[0026] In the pressurizing stage and the pressurized return stage, the piston rod 35 sliding inside the first cylinder 20 is stopped by operating a shutoff valve linked to the first cylinder 20. Therefore, in the pressurizing stage and the pressurized return stage, the booster rod 60 of the two-stage cylinder 10 is operated only by the air pressure supplied from the air adjustment port 80.

[0027] In the pressurizing stage, air is injected from an air adjustment port 80 (on the upper side of the second cylinder 30) to generate air pressure, which lowers the intensifier piston 50 slidably installed inside the second cylinder 30. This causes the intensifier rod 60 slidably installed inside the second cylinder 30 to lower, allowing crimping work, press-fitting work, etc. to be performed (see FIG. 3(c)).

[0028] On the other hand, in the pressurization return stage, the intensifier piston 50, which is slidably installed inside the second cylinder 30, is raised by the air pressure generated by injecting air from the air adjustment port 80 (below the second cylinder 30). As a result, the intensifier rod 60, which is slidably installed inside the second cylinder 30, rises and returns to the pressurization start position (see FIG. 3(d)).

[0029] After the pressurized return stage is completed, the shutoff valve linked to the first cylinder 20 is returned from the stopped state to the operating state, and the first cylinder 20 (hydraulic) equipped with the piston rod 35 is actuated to return to its original position, thus completing the operating cycle of the two-stage cylinder 10 (see Fig. 3(e)).

[0030] <Two-stage cylinder structure (non-fastening type)> The two-stage cylinder 11 (non-fastening type) is a two-stage cylinder 11 having a two-stage cylinder structure with a side having a larger cylinder diameter and a side having a smaller cylinder diameter (characterized by being non-fastened). As shown in Fig. 4, it is equipped with a first cylinder 20 (the cylinder with the smaller cylinder diameter) equipped with a slidably installed piston rod 35, a second cylinder 30 which is the cylinder with the larger cylinder diameter, a propulsion piston 40 connected to the rod side of the piston rod 35 installed in the first cylinder 20 and installed slidably inside the second cylinder 30, and a booster piston 50 and booster rod 60 (output shaft) installed slidably inside the second cylinder 30 at a position facing the propulsion piston 40.

[0031] Furthermore, air adjustment ports 80 (three locations in total) are provided at (near) the upper end of the second cylinder 30, at (near) the lower end of the second cylinder 30, and at the fast-forward end position below the second cylinder 30 (the stop position of the propulsion piston 40, the boundary position between the propulsion piston 40 and the booster piston 50) for injecting air into the second cylinder 30 or for discharging (vacuuming) air from the second cylinder 30.

[0032] A feature of the two-stage cylinder 11 is that it is equipped with a propulsion piston 41, which is a component not found in conventional two-stage cylinders (the propulsion piston 41 and the booster piston 50 have the same opposing surface shapes and pressure-receiving areas). To explain further, the propulsion piston 41 and the booster piston 50 (which are in surface contact) are not fastened together by fastening members or the like, and are in a so-called unclamped state.

[0033] The two-stage cylinder 11 operates as follows: the piston rod 35 and the propulsion piston 41, which slide within the hydraulically operated first cylinder 20, descend to the starting position for crimping, press-fitting, or other operations (on a production line) (during fast forward). Air is then injected through the air adjustment port 80 (located at the bottom of the second cylinder 30, at the end of the fast forward movement) (and simultaneously exhausted from the air adjustment port 80 at the bottom of the second cylinder 30). This generates air pressure (filling the space between the propulsion piston 41 and the propulsion piston 50), which then causes the propulsion piston 50 and the propulsion rod 60, which slide freely within the second cylinder 30, to descend (during pressurization). The reason for using a hydraulic cylinder for the first cylinder 20 is that if the pressure medium is a compressible medium such as air, the piston position may fluctuate during operation (even with a shutoff valve). In other words, if the pressure medium is an incompressible medium such as oil, the piston position does not fluctuate during operation.

[0034] FIG. 5 is a diagram illustrating an improved version of the two-stage cylinder 10 (installation of an air adjustment pipe 90). The difference from the two-stage cylinder 10 is that, as shown in FIG. 5, an air adjustment pipe 90 is installed on the top surface of the second cylinder 30, which is the cylinder with the larger cylinder diameter, instead of the air adjustment port 80 that was installed near the top end of the second cylinder 30. The air adjustment pipe 90 (for vacuuming or air injection) has an insertion hole (on the top surface of the second cylinder 30) and passes through the insertion hole from the top surface of the propulsion piston 40 to the bottom surface of the propulsion piston 40 (through the propulsion piston 40). In the improved version of the two-stage cylinder 11, the air adjustment port 80 is installed near the bottom end of the second cylinder 30, and a breathing hole 100 is installed near the top end of the second cylinder 30.

[0035] To ensure that the air supplied from the air adjustment pipe 90 efficiently presses down on the booster piston 50, a thrust adjustment space 110 (a recess in the thrust piston 40) is formed on the underside of the propulsion piston 40 (the side facing the booster piston 50) where it abuts against the air adjustment pipe 90. The vertical dimension (height) of the thrust adjustment space 110 is preferably 10% to 20% of the vertical dimension (height) of the propulsion piston 40, and the cross-sectional area of ​​the thrust adjustment space 110 is preferably 10% to 30% of the cross-sectional area of ​​the booster piston 50. The shape of the thrust adjustment space 110 (the recess in the propulsion piston 40) is preferably a (thin) cylindrical shape, but may be any other three-dimensional shape.

[0036] <Operation cycle of two-stage cylinder (non-fastening type)> FIG. 6 is a diagram illustrating the operating cycle of the two-stage cylinder 11. In this specification, the improved version (FIG. 5) will be mainly described. As shown in FIG. 6, the operating cycle of the two-stage cylinder 11 is repeated in the following order: original position stage (a) → fast-forward stage (b) → pressure stage (c) → pressure return stage (d) → original position stage (e) ((a) and (e), and (b) and (d) have the same positional relationship). The two-stage cylinder 11 is positioned (start positioning for crimping work, etc.) in the original position stage (a) → fast-forward stage (b). In actual production lines, crimping work, press-fitting work, etc. are performed in the pressure stage (c) → pressure return stage (d) (the sequence is repeated multiple times, such as pressure stage (c) → pressure return stage (d) → pressure stage (c) → pressure return stage (d)...). The operating cycle then ends in the pressure return stage (d) → original position stage (e).

[0037] <Original position stage (a)(e)> The original position stage is the starting point and the end point of the operating cycle of the two-stage cylinder 11. The positions of the piston rod 35 slidably installed inside the first cylinder 20 (the cylinder with the smaller cylinder diameter), the second cylinder 30 (the cylinder with the larger cylinder diameter), the propulsion piston 41 slidably installed inside the second cylinder 30 and connected to the rod side of the piston rod 35 installed inside the first cylinder 20, and the booster piston 50 and booster rod 60 (output shaft) slidably installed inside the second cylinder 30 at a position facing the propulsion piston 41 are as shown in Figure 6(a).

[0038] <Fast-forward stage (b)> The fast-forward stage is a stage in which the tip position of the intensifier rod 60 is fast-forwarded from its original position to a start position where crimping, press-fitting, and other processes are actually performed on a production line, etc. (see FIG. 6(b)). In the fast-forward stage, a vacuum is drawn through the air adjustment pipe 90 to prevent a gap from forming between the propulsion piston 40 and the intensifier piston 50, and the piston rod 35 sliding downward inside the first cylinder 20 (hydraulic) is slid downward while adjusting the air adjustment port 80 so that air accumulates at the bottom of the second cylinder 30 from the air adjustment port 80 (to ensure a stroke in the pressurization stage). In conjunction with this movement, the intensifier piston 50 and the intensifier rod 60 slide downward inside the second cylinder 30. This lowers the intensifier rod 60 from its original position to a start position where crimping, press-fitting, and other processes are actually performed on a production line, etc. The moment it reaches the start position, a shutoff valve linked to the first cylinder 20 is activated, and the piston rod 35 that slides inside the first cylinder 20 stops (see FIG. 6(b)).

[0039] <Pressure stage (c) and pressure return stage (d)> The pressurizing stage and the pressurizing return stage are stages where crimping work, press-fitting work, etc. are actually performed in a production line, etc. The crimping work and press-fitting work begin with the workpiece being set so that the tip of the intensifier rod 60 is in contact with the workpiece (or so that the tip of the intensifier rod 60 is at a position just before contacting the workpiece) (see FIG. 6(b)).

[0040] In the pressurizing stage and the pressurized return stage, the piston rod 35 sliding inside the first cylinder 20 is stopped by operating a shutoff valve linked to the first cylinder 20. Therefore, in the pressurizing stage and the pressurized return stage, the booster piston 50 and the booster rod 60 of the two-stage cylinder 11 are operated only by the air pressure supplied from the air adjustment pipe 90 or the air adjustment port 80.

[0041] In the pressurizing stage, the booster piston 50, which is slidably installed inside the second cylinder 30, is lowered by air pressure generated by injecting air from the air adjustment pipe 90 (the propulsion piston 40 does not move). At the same time, air accumulated at the bottom of the second cylinder 30 is discharged from the air adjustment port 80. This causes the booster rod 60 (together with the booster piston 50), which is slidably installed inside the second cylinder 30 and is installed in a position opposite the propulsion piston 40, to lower, thereby allowing crimping work, press-fitting work, etc. to be performed (see FIG. 6(c)).

[0042] Meanwhile, in the pressurization return stage, the booster piston 50, which is slidably installed inside the second cylinder 30, is raised by air pressure generated by injecting air from the air adjustment port 80. At the same time, a vacuum is drawn from the air adjustment pipe 90 to the space between the propulsion cylinder 40 and the booster cylinder 50 inside the second cylinder 30. This causes the booster rod 60 (together with the booster piston 50), which is slidably installed inside the second cylinder 30, to rise to a position facing the propulsion piston 40, and returns to the pressurization start position (see FIG. 6(d)).

[0043] After the pressurized return stage is completed, the shutoff valve linked to the first cylinder 20 is returned from the stopped state to the operating state, and the first cylinder 20 (hydraulic) equipped with the piston rod 35 is actuated to return to its original position, thus completing the operating cycle of the two-stage cylinder 11 (see Fig. 6(e)).

[0044] <Effect of two-stage cylinder> According to the present invention, even in a two-stage cylinder that is an energy-saving air cylinder that outputs full power only at the end of the stroke and reduces air consumption midway through the stroke, by eliminating the attachment / detachment mechanism for fastening the booster piston 50 to the propulsion connector 40, which is installed slidably inside the second cylinder 30, and by installing the booster piston 50 slidably inside the second cylinder 30 while leaving the propulsion connector 40 fixed, and by installing the booster piston 50 slidably inside the second cylinder 30 without fastening the propulsion piston 41 and the booster piston 50 (installed in a position opposite the propulsion piston 41), it is possible to provide two-stage cylinders 10, 11 with a structure that is not easily damaged (due to wear and deterioration), by eliminating mechanisms that are easily damaged (due to wear and deterioration).

[0045] Furthermore, by installing the air adjustment pipe 90 instead of the air adjustment port 80 installed at the top of the second cylinder (holes in the sliding surface would lead to wear of the propulsion piston 40), it has become possible to withstand long-term use. In other words, when the propulsion piston 40 reciprocates on the inner wall of the second cylinder 30, it is no longer damaged by friction with the air adjustment port 80 (installed at the top of the second cylinder), and damage due to wear and the like can be reduced.

[0046] The two-stage cylinders 10, 11 of the present invention are so-called oil-air cylinders, which use hydraulic pressure to move the piston to a certain position, then turn off the hydraulic pressure and supply air to complete the final work using pneumatic pressure. This method allows for the use of pneumatic pressure, which is less expensive and more environmentally friendly than hydraulic pressure. However, conventional two-stage cylinders have a problem with oil leakage. The two-stage cylinders 10, 11 are designed so that oil is injected only into the first cylinder 20, but not into the second cylinder. Therefore, the area where oil leakage would occur from the first cylinder 20 (around the inner surface of the end cap of the first cylinder 20, which is prone to wear due to the sliding of the piston rod 35 as the propulsion connector 40 moves up and down) is surrounded by the second cylinder 30 (because it is inside the second cylinder 30), eliminating the risk of oil leakage.

[0047] Furthermore, a slide member 62 is installed between the outer circumferential surface of the intensifier rod 60 (on the second cylinder 30 side) and the inner surface of the end cap of the second cylinder 30, where friction (with the intensifier rod 60) occurs when the intensifier rod 60 slides. In addition to the slide member 62, a dust seal member 64 is installed on the bottom surface of the end cap, below the slide member 62. By installing these members, the intensifier piston 50 (the output shaft) and the intensifier rod 60 are supported from both sides, creating a so-called "double-supported" state, which stabilizes operation and prevents oil leakage. As a result, the seal portion (the area around the inner surface of the end cap of the first cylinder 20, which is prone to wear due to the rising and falling of the propulsion connector 40 caused by the sliding of the piston rod 35) is protected from friction and vibration generated when the two-stage cylinders 10, 11 operate, thereby extending the life of the cylinders.

[0048] <Example of a two-stage cylinder change> The two-stage cylinder according to the present invention is not limited to the aspects of the above-described embodiments, and the configurations of the first cylinder, second cylinder, propulsion connector, propulsion piston, propulsion connector fixing member, booster piston, booster rod, slide member, dust seal member, air adjustment port, air adjustment pipe, breathing hole, thrust adjustment space, etc. can be appropriately changed as needed without departing from the spirit of the present invention. Furthermore, although the two-stage cylinder according to the present invention has a hydraulic cylinder as the first cylinder and an air cylinder as the second cylinder, it will still function even if the fluids in the first and second cylinders are swapped. [Industrial Applicability]

[0049] The two-stage cylinder of the present invention has the excellent effects described above, and can therefore be suitably used as an air cylinder that outputs full power only at the end of the stroke to increase pressure when performing crimping, press-fitting, etc., thereby reducing air consumption during the stroke. [Explanation of symbols]

[0050] 10. Two-stage cylinder (fastening type) 11. Two-stage cylinder (non-fastening type) 20 First cylinder 30··Second cylinder 35 Piston rod (first cylinder side) 40··Propulsion Connector 41. Propulsion piston 44 Propulsion connector fixing member 50··Boosting piston 60··Booster rod 62 Slide member 64 Dust seal member 80··Air adjustment port 90··Air adjustment pipe 100...breathing hole 110... Thrust adjustment space

Claims

1. A two-stage cylinder has a two-stage structure with a cylinder on the side with a smaller cylinder diameter and a cylinder on the side with a larger cylinder diameter, and is composed of a first cylinder which is the cylinder on the side with a smaller cylinder diameter and a second cylinder which is the cylinder on the side with a larger cylinder diameter, a piston rod slidably installed inside the first cylinder; and a propulsion connector connected to a rod side of the piston rod installed inside the first cylinder and slidably installed inside the second cylinder; A two-stage cylinder characterized in that the propulsion connector is fixed to an upper (first cylinder side) recess, and the second cylinder is provided with a booster piston and a booster rod that are slidably installed inside the second cylinder.

2. A two-stage cylinder has a two-stage structure with a side with a larger cylinder diameter and a side with a smaller cylinder diameter, and is composed of a first cylinder which is the cylinder on the side with a smaller cylinder diameter and a second cylinder which is the cylinder on the side with a larger cylinder diameter, a piston rod slidably installed inside the first cylinder; and a propulsion piston connected to a rod side of the piston rod installed in the first cylinder and slidably installed inside the second cylinder; A two-stage cylinder comprising a booster piston and a booster rod slidably installed inside the second cylinder at a position facing the propulsion piston.

3. 3. The two-stage cylinder according to claim 2, wherein an insertion hole is provided on the upper surface of the second cylinder, the thrust piston passes through the insertion hole from the upper surface of the thrust piston, and an air adjustment pipe is further provided that reaches the lower surface of the thrust piston.

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