Hydraulic cylinder device

Abstract

To provide a hydraulic cylinder device for enabling a further reduction in the load applied to the rod cover side even when a hydraulic pressure generated in the hydraulic cylinder device is higher.SOLUTION: The hydraulic cylinder device has a piston 8 for reciprocating in a cylindrical chamber formed by a cylinder 1. The cylinder 1 includes a cylinder body 2 using a bottom face 2B opposed to a top face 8A of the piston 8 and a cylindrical face 2A to form a cylinder chamber S, a rod cover 6 connected to the cylinder body 2 for closing the cylinder chamber S, and a cylindrical member mounted to the cylindrical chamber for guiding the piston 8, the cylindrical member having an annular inward flange 3B, and an annular groove part 3Ba on the outer face opposed to the bottom face 2B of the inward flange 3B. By an annular seal member 5 mounted to the groove part 3Ba, a space between the bottom face 2B and the inward flange 3B is sealed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hydraulic cylinder device. The present invention is a technology suitable for a hydraulic cylinder device for generating high hydraulic pressure, such as a hydraulic cylinder device for generating a rolling force of a rolling mill.

Background Art

[0002] As a device that utilizes the high load generated by a hydraulic cylinder device, for example, there is a rolling mill. Here, conventionally, in a rolling mill and a rolling method, a technique has been disclosed in which rolling accuracy is improved by appropriately applying a rolling force to a rolling roll to perform stable rolling. As an example, in thick plate rolling, a hydraulic cylinder device having a bender cylinder and a balance cylinder functions during rolling to produce a steel material with excellent accuracy. This applies forces in the vertical and longitudinal directions to the roll shaft portions (also referred to as clutches) provided at both ends of the roll body to give the roll body deflections in the vertical and longitudinal directions. As a result, the hydraulic cylinder device improves the sheet thickness accuracy and the like.

[0003] Such a technique is described in a plurality of patent documents, such as Patent Document 1. Patent Document 1 describes, as a hydraulic cylinder device, for example, left and right rolling cylinders that constitute a rolling device. Each rolling cylinder has a configuration in which a cylindrical member is coaxially fitted into a cylindrical cylinder chamber formed by a cylinder case, and the piston can smoothly advance and retreat by the cylindrical member.

[0004] Here, conventionally, a hydraulic cylinder device for high pressure used for pressing or the like has a cylinder case made of a large block. And, a plating process for improving slidability was performed on the inner surface of the cylinder chamber. However, since the cylinder case is a large block, it is difficult to ensure the uniformity of the plating thickness during plating construction. Also, over time, the plating on the cylinder sliding part may get scratched, unevenly worn, or peeled off. Such things have an adverse effect on the seal on the piston side, such as chipping or scratching, and have been the cause of oil leakage. Furthermore, even during plating repair, there are concerns about prolonging the removal and attachment of the shift block and unevenness in re-plating, which may also become a factor of trouble.

[0005] Therefore, as described in Patent Document 1, a cylindrical member pre-plated on its inner diameter surface is fitted into the cylinder chamber of the cylinder case. By mounting this cylindrical member, it becomes possible to provide a sliding surface with uniform plating in a simple and easy-to-maintain form.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, according to the inventors' investigation, it has been found that in thick plate rolling or the like, when the above-mentioned cylindrical member is mounted, there is a possibility that the following problems may occur compared to the case where the cylindrical member is not mounted. The problem is that as the material to be rolled becomes a high-load material, the bolts for fixing the rod cover to the cylinder case may be damaged, and bolt breakage causes oil leakage. Note that the rod cover is a component that closes the cylinder chamber formed by the cylinder case with a hole through which the piston rod passes opened. This rod cover is fixed to the cylinder case by bolt connection.

[0008] The present invention has been made paying attention to the above points, and an object thereof is to make it possible to further reduce the load applied to the rod cover side even when the hydraulic pressure generated in the hydraulic cylinder device becomes high pressure.

Means for Solving the Problems

[0009] The inventor repeatedly conducted various studies on the above problems and obtained the following findings. When a cylindrical member is attached to the cylinder chamber, the pressure in the hydraulic pressure chamber that generates hydraulic pressure is applied to the end face on the side opposite to the rod cover in the cylindrical member, and that load is applied to the rod cover via the cylindrical member. In addition, due to the increase in high-load materials in recent years, the surge pressure acting on the cylinder has become higher. For this reason, the inventor obtained the finding that the load applied to the rod cover also increases, and the load applied to the bolts fixing the rod cover also increases, which has been the cause of bolt breakage. Then, the inventor considered reviewing the pressure balance in the cylinder by changing the shape of the cylindrical member and suppressing bolt breakage troubles. And the present invention was completed.

[0010] That is, in order to solve the problems, one aspect of the present invention is a hydraulic cylinder device in which a piston reciprocates in a cylinder chamber formed by a cylinder, the cylinder includes a cylinder body that forms the cylinder chamber with a bottom surface facing the top surface of the piston and a cylindrical surface whose axis faces in the advancing and retreating direction of the piston and is continuous with the outer periphery of the bottom surface, a rod cover that is connected to the cylinder body, has an opposing surface facing the bottom surface of the cylinder body, and closes the cylinder chamber, and a cylindrical member that is attached to the cylindrical surface and guides the piston. The cylindrical member has an annular inward flange that extends in the circumferential direction and the inner diameter direction and abuts on the bottom surface. On the outer surface of the inward flange facing the bottom surface, there is an annular groove portion that extends along the extending direction of the inward flange, and the hydraulic cylinder device includes an annular seal member that is attached to the groove portion and seals between the bottom surface and the inward flange.

Effects of the Invention

[0011] According to an aspect of the present invention, by devising the shape of the cylindrical member attached to the cylinder chamber, even when the hydraulic pressure generated in the hydraulic cylinder device becomes high pressure, the load applied to the rod cover side can be further reduced. As a result, according to an aspect of the present invention, while achieving the above-described effects by attaching the cylindrical member, it is possible to improve the durability of the device.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Next, embodiments of the present invention will be described with reference to the drawings. (Configuration) As shown in FIG. 1, the hydraulic cylinder device of the present embodiment includes a cylinder 1 and a piston 8 that reciprocates within a cylinder chamber S formed by the cylinder 1. The cylinder 1 of the present embodiment includes a cylinder body 2, a rod cover 6, and a cylindrical sleeve 3 that constitutes a cylindrical member (liner).

[0014] The cylinder body 2 corresponds to a cylinder tube. The cylinder body 2 is formed with a bottom surface 2B and a cylindrical surface 2A continuous with the outer periphery of the bottom surface 2B, and the space formed by the bottom surface 2B and the cylindrical surface 2A constitutes the cylinder chamber S. The cylinder body 2 of the present embodiment is configured as a thick-walled integral body so as to withstand the generated high pressure. The piston 8 is disposed in the cylinder chamber S so as to be able to move forward and backward, and the bottom surface 2B faces the top surface 8A (crown surface) of the piston 8. And, in the cylinder chamber S, the space between the bottom surface 2B and the top surface 8A constitutes a hydraulic chamber SA (pressure generating chamber).

[0015] The rod cover 6 has a facing surface facing the bottom surface 2B of the cylinder main body 2, and closes the space (cylinder chamber S) formed by the bottom surface 2B and the cylindrical surface 2A. A hole through which the piston rod 9 penetrates is opened at the center of the rod cover 6. And the rod cover 6 is fixed to and connected to the cylinder main body 2 by a plurality of bolts 7. The sleeve 3 is a liner part that is mounted so as to be fitted into the cylindrical surface 2A, and smoothly guides the piston 8 while ensuring liquid tightness with the piston 8. The sleeve 3 is made of iron. In the present embodiment, the axial length of the sleeve 3 is set to be equal to the facing distance between the bottom surface 2B and the facing surface.

[0016] As shown in FIG. 1, the sleeve 3 of the present embodiment has an annular inward flange 3B that extends in the circumferential direction and the inner diameter direction with respect to the end on the bottom surface 2B side and abuts against the bottom surface 2B. That is, the sleeve 3 of the present embodiment includes a cylindrical main body 3A having a cylindrical shape and an inward flange 3B formed at the end on the bottom surface 2B side of the cylindrical main body 3A. The end face on the bottom surface side of the cylindrical main body 3A and the outer surface 3BA of the inward flange 3B are flush with each other.

[0017] As shown in FIG. 2 which is a plan view seen from the axial direction, the inward flange 3B has an annular shape. An annular groove portion 3Ba extending along the extending direction of the inward flange 3B is formed on the outer surface 3BA (the surface on the bottom surface 2B side) of the inward flange 3B. This groove portion 3Ba constitutes a seal member mounting portion. And, an O-ring or other annular seal member 5 extending along the groove portion 3Ba is attached to the annular groove portion 3Ba. By this annular seal member 5, the space between the bottom surface 2B and the inward flange 3B is sealed so as to block the outer peripheral side from the hydraulic oil than the installation position of the seal member 5.

[0018] Further, a sliding property improvement layer 4 for improving the sliding with the piston 8 is formed on the inner diameter surface of the cylindrical portion main body 3A. The sliding property improvement layer 4 is constituted by, for example, hard chromium plating. The sliding property improvement layer 4 is not limited to hard chromium plating as long as the sliding property with the piston 8 can be improved. The annular groove portion 3Ba for attaching the seal member 5 is located radially inward of the cylindrical portion main body 3A. It is preferable that the position is close to the inner diameter side of the inward flange 3B. Note that two or more sets of the annular groove portion 3Ba and the seal member 5 attached to the groove portion 3Ba may be provided concentrically.

[0019] (Operation and others) Fig. 4 shows a schematic diagram of the structure of a hydraulic cylinder device in a comparative example. In this comparative example, it is an example in which the inward flange 3B is not provided on the sleeve 3 (cylindrical member) disposed in the cylinder chamber S. In this comparative example, even when the end surface of the sleeve 3 abuts on the bottom surface 2B, the pressure generated in the hydraulic chamber SA is loaded on the end surface on the bottom surface 2B side of the sleeve 3 as indicated by the arrow. The pressure applied to this sleeve 3 acts in a direction to separate the rod cover 6 from the cylinder main body 2 via the sleeve 3, and the greater the hydraulic pressure (pressure) generated by the hydraulic cylinder device, the greater the load on the bolt 7. Then, every time a surge pressure is generated, an excessive load is applied to the rod cover 6, and there is a risk that the bolt 7 fixing the rod cover 6 may be damaged due to the load.

[0020] Here, since the chamber on the rod cover 6 side in the cylinder chamber S is not a pressure generating chamber, this trouble is a trouble peculiar to when the sleeve 3 is mounted. On the other hand, in the present embodiment, a simple configuration is adopted in which an inward flange 3B is provided on the sleeve 3 and the seal member 5 is attached to the inward flange 3B, thereby preventing the above-mentioned trouble. Also in the present embodiment, the pressure generated in the pressure generating chamber is applied to the outer surface 3BA of the sleeve 3 facing the bottom surface 2B. However, as shown in FIG. 3, the surface on which the pressure is applied is a region on the inner diameter side of the outer surface 3BA of the inward flange 3B (the surface facing upward in FIG. 3) that is closer to the inner diameter than the position where the seal member 5 is disposed.

[0021] Furthermore, in the present embodiment, as shown in FIG. 3, the same pressure also acts on the entire inner surface 3BB of the inward flange 3B (the surface facing downward in FIG. 3). As can be seen from FIG. 3, since the upward pushing force acting on the inner surface 3BB of the inward flange 3B is greater than the downward pressing force acting on the outer surface 3BA of the inward flange 3B, even if an excessive hydraulic pressure is generated in the hydraulic chamber SA (pressure generating chamber) due to the surge pressure, the generation of a load applied to the rod cover 6 via the sleeve 3 can be prevented. As a result, there is no risk of the bolt 7 fixing the rod cover 6 being damaged due to the surge pressure.

[0022] Also, the upward pushing force increases as the hydraulic pressure increases. Therefore, as the hydraulic pressure increases, the inward flange 3B is pressed against the bottom surface 2B by the upward pushing force, and the sealing performance of the seal member 5 is surely exerted. This means that even if the length of the sleeve 3 is shorter than the cylinder chamber S, the inward flange 3B is pressed against the bottom surface 2B by the hydraulic pressure, and the seal by the seal member 5 works.

[0023] As described above, in the present embodiment, even when the sleeve 3 is attached to the cylinder chamber S to improve the maintainability of the hydraulic cylinder device and the like, the bolt 7 that fixes the rod cover 6 is prevented from being damaged by the pressure in the hydraulic chamber SA. As a result, troubles such as oil leakage can be suppressed.

[0024] (Other) The present disclosure can also adopt the following configuration. (1) A hydraulic cylinder device in which a piston reciprocates in a cylinder chamber formed by a cylinder, The cylinder is, A cylinder body that forms the cylinder chamber with a bottom surface facing the top surface of the piston and a cylindrical surface whose axis is directed in the advancing and retreating direction of the piston and that is continuous with the outer periphery of the bottom surface, Connected to the cylinder body, having a facing surface facing the bottom surface of the cylinder body, and a rod cover that closes the cylinder chamber, A cylindrical member mounted on the cylindrical surface to guide the piston, Comprising, The cylindrical member has an annular inward flange that extends in the circumferential direction and the inner diameter direction and abuts against the bottom surface, The outer surface of the inward flange facing the bottom surface has an annular groove portion that extends along the extending direction of the inward flange, An annular seal member that is attached to the groove portion and seals between the bottom surface and the inward flange is provided. A hydraulic cylinder device characterized by this. (2) A sliding property improvement layer for improving sliding with the piston is formed on the inner diameter surface of the cylindrical member. (3) The axial length of the cylindrical member is equal to the facing distance between the bottom surface and the facing surface. (4) The cylindrical member includes a cylindrical member body and the inward flange formed at the bottom surface side end portion of the cylindrical member body, The annular groove portion is located radially inside the cylindrical member body.

Explanation of Signs

[0025] 1 Cylinder 2 Cylinder body 2A Cylindrical surface 2B Bottom surface 3 Sleeve 3A Cylindrical member body 3B Inward flange 3Ba Groove portion 4 Sliding property improvement layer 5 Seal member 6 Rod cover 7 bolts 8 pistons 8A top surface 9 piston rods S cylinder chamber SA hydraulic chamber

Claims

1. A hydraulic cylinder device in which a piston reciprocates in a cylinder chamber formed by a cylinder, wherein the cylinder includes a cylinder body that forms the cylinder chamber with a bottom surface facing the top surface of the piston and a cylindrical surface whose axis is oriented in the advancing and retreating direction of the piston and that is continuous with the outer periphery of the bottom surface, a rod cover that is connected to the cylinder body, has a facing surface facing the bottom surface of the cylinder body, and closes the cylinder chamber, and a cylindrical member that is fitted and attached to the cylindrical surface and guides the piston, and is provided with the cylindrical member has a cylindrical portion body that contacts the cylindrical surface and an annular inward flange that is formed at the bottom surface side end of the cylindrical portion body and extends in the circumferential direction and the inner diameter direction to contact the bottom surface, an outer surface of the inward flange facing the bottom surface has an annular groove portion that extends along the extending direction of the inward flange, and is provided with an annular seal member that is attached to the groove portion and seals between the bottom surface and the inward flange, the annular groove portion is located radially inward of the inner diameter surface of the cylindrical portion body, characterized in that it is a hydraulic cylinder device.

2. a slidability improvement layer for improving sliding with the piston is formed on the inner diameter surface of the cylindrical portion body, the annular groove portion is located radially inward of the slidability improvement layer, characterized in that it is the hydraulic cylinder device according to claim 1.

3. the axial length of the cylindrical member is equal to the facing distance between the bottom surface and the facing surface, characterized in that it is the hydraulic cylinder device according to claim 1.

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