Hydraulic system for fork lift truck, fork device, fork lift truck, and leakage judgment method

Abstract

The application specifically relates to a hydraulic system for a forklift, a fork device, a forklift and a leakage judgment method, which comprises the following steps: an oil return assembly is arranged on the outer wall of a cylinder assembly, and when the oil seal of the cylinder assembly leaks, hydraulic oil in the cylinder assembly enters the oil return assembly; the oil return assembly comprises a joint and an oil return pipe; the joint is connected with the side wall of the cylinder assembly; the bottom of the joint is sleeved with the oil return pipe; a plurality of clamping holes are arranged in the side wall of the joint; the inner wall of the oil return pipe is provided with clamping blocks corresponding to the clamping holes; when the clamping blocks are inserted into the corresponding clamping holes, an observation hole exists between the top surface of the clamping blocks and the inner top surface of the clamping holes; when it is necessary to judge whether the oil seal leaks, the folding part connected with the end of the oil return pipe is folded downward, so that the observation hole is exposed, whether the hydraulic oil exists in the oil return pipe is judged through the observation hole, and whether the hydraulic oil exists in the oil return pipe can be judged without completely pulling the oil return pipe out of the joint, so that whether the oil seal leaks can be judged.

Description

Forklift hydraulic systems, fork attachments, forklifts and leakage detection methods Technical Field

[0001] This invention belongs to the technical field of fluid pressure actuators, specifically relating to fluid pressure actuators, and more particularly to a hydraulic system for forklifts, a fork assembly, a forklift, and a method for leak detection. Background Technology

[0002] When the hydraulic cylinder of a forklift reaches its highest position, it may drop. This is because there is a problem with the oil seal in the cylinder. In this case, the problem is usually solved by separating the return oil pipe from the connector on the cylinder. If hydraulic oil flows out of the connector, it indicates that there is a problem with the oil seal. However, the relevant technology requires that the return oil pipe be completely disconnected from the connector in order to observe whether there is hydraulic oil flowing out of the connector. The length of the return oil pipe and the connector is relatively long, making it difficult to disassemble the return oil pipe. In addition, due to the harsh working environment of forklifts, when the return oil pipe is disassembled, a large amount of dust from the environment will enter the return oil pipe and cause it to be contaminated.

[0003] Therefore, due to the difficulty in disassembling the return oil pipe to check for hydraulic oil after disconnecting it from the connector, and the fact that a large amount of dust from the environment can enter the return oil pipe and cause contamination due to the poor operating environment of forklifts, it is necessary to design a hydraulic system for forklifts, fork assembly, forklift, and leakage detection method.

[0004] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0005] This disclosure provides at least one hydraulic system for forklifts, a fork assembly, a forklift, and a method for determining leakage.

[0006] In a first aspect, embodiments of this disclosure provide a hydraulic system for a forklift, comprising:

[0007] A hydraulic cylinder assembly is provided with a return oil assembly on its outer wall. When the oil seal of the hydraulic cylinder assembly leaks, the hydraulic oil in the hydraulic cylinder assembly enters the return oil assembly, and the presence of hydraulic oil in the return oil assembly indicates that the oil seal is leaking.

[0008] The oil return assembly includes: a connector and an oil return pipe;

[0009] The connector is connected to the side wall of the cylinder assembly;

[0010] The return oil pipe is sleeved at the bottom of the joint, and the side wall of the joint is provided with several snap-fit ​​holes. The inner wall of the return oil pipe is provided with snap-fit ​​blocks corresponding to the snap-fit ​​holes. When the snap-fit ​​block is inserted into the corresponding snap-fit ​​hole, there is an observation hole between the top surface of the snap-fit ​​block and the inner top surface of the snap-fit ​​hole.

[0011] When it is necessary to determine whether the oil seal is leaking, fold down the folded part connected to the end of the return oil pipe to expose the observation hole. Use the observation hole to determine whether there is hydraulic oil in the return oil pipe. If there is hydraulic oil in the return oil pipe, it is determined that the oil seal is leaking.

[0012] In one optional embodiment, a folding clearance groove is provided on the outer wall of the folding part near the end of the return oil pipe;

[0013] The connection position between the folded part and the end of the return oil pipe corresponds to the observation hole;

[0014] When the return oil pipe is fitted at the bottom of the joint, the folded part is fitted outside the joint to cover the observation hole.

[0015] In one optional embodiment, the return oil pipe is provided with a flexible section;

[0016] When the folded part folds down and comes into contact with the flexible part, a clamp is set outside the folded part to squeeze the folded part and the flexible part, causing the flexible part to contract inward until it contacts the inner wall, thereby reducing the inner diameter of the return oil pipe. If there is hydraulic oil in the return oil pipe at this time, the reduced inner diameter of the return oil pipe will hinder the flow of hydraulic oil.

[0017] In one alternative embodiment, when the folded part is fitted over the joint, the folded part is tightened by a clamp.

[0018] The inner bottom surface of the snap-fit ​​hole is an inclined surface, and the bottom surface of the snap-fit ​​block is also an inclined surface. When the snap-fit ​​block is inserted into the snap-fit ​​hole, the bottom surface of the snap-fit ​​block contacts the inner bottom surface of the snap-fit ​​hole.

[0019] The card block is made of a flexible material.

[0020] In one alternative embodiment, when it is necessary to remove the return oil pipe from the connector, the folded part is in a downward folded state. A clamp is set outside the folded part to squeeze the folded part and the flexible part, so that the flexible part contracts inward to reduce the inner diameter of the return oil pipe. Then the return oil pipe is removed from the connector.

[0021] In one alternative embodiment, the cylinder assembly includes: a cylinder body and a telescopic shaft;

[0022] The telescopic shaft is slidably disposed within the cylinder body, and the top end of the telescopic shaft extends from the top end of the cylinder body;

[0023] An oil seal is provided between the outer wall of the telescopic shaft and the inner wall of the cylinder.

[0024] The connector is connected to the outer wall of the cylinder and communicates with the inside of the cylinder, with the communication position close to the top of the cylinder.

[0025] In one optional embodiment, a hydraulic oil pipe is provided on the side wall of the cylinder near the bottom of the cylinder. When the telescopic shaft needs to rise, hydraulic oil is introduced through the hydraulic oil pipe between the bottom surface of the cylinder and the bottom of the telescopic shaft to drive the telescopic shaft to move upward.

[0026] Secondly, this disclosure also provides a fork device employing the above-described hydraulic system for forklifts, comprising:

[0027] The mast body and the movable frame slidably connected to the mast body, the cylinder assembly in the hydraulic system of the forklift is connected to the mast body, and the telescopic shaft in the cylinder assembly is connected to the movable frame to drive the movable frame to move up and down along the mast body;

[0028] The mobile frame is equipped with forklift assembly.

[0029] Thirdly, embodiments of this disclosure also provide a forklift, comprising:

[0030] The aforementioned forklift assembly.

[0031] Fourthly, this disclosure also provides a method for determining leakage of hydraulic oil in the above-described hydraulic system for forklifts, comprising:

[0032] When the oil seal of the cylinder assembly leaks, the hydraulic oil in the cylinder assembly enters the return oil assembly, and the presence of hydraulic oil in the return oil assembly indicates that the oil seal is leaking.

[0033] When it is necessary to determine whether the oil seal is leaking, fold down the folded part connected to the end of the return oil pipe to expose the observation hole. Use the observation hole to determine whether there is hydraulic oil in the return oil pipe. If there is hydraulic oil in the return oil pipe, it is determined that the oil seal is leaking.

[0034] The beneficial effects of this invention are as follows: The hydraulic system for forklifts includes a cylinder assembly, on the outer wall of which a return oil assembly is provided. When the oil seal of the cylinder assembly leaks, the hydraulic oil in the cylinder assembly enters the return oil assembly, and the presence of hydraulic oil in the return oil assembly indicates oil seal leakage. The return oil assembly includes a connector and a return oil pipe. The connector is connected to the side wall of the cylinder assembly. The return oil pipe is sleeved on the bottom of the connector. The side wall of the connector has several snap-fit ​​holes. The inner wall of the return oil pipe has snap-fit ​​blocks corresponding to the snap-fit ​​holes. When the snap-fit ​​blocks are inserted into the corresponding snap-fit ​​holes, there is an observation hole between the top surface of the snap-fit ​​block and the inner top surface of the snap-fit ​​hole. When it is necessary to determine whether the oil seal is leaking, the folded part connected to the end of the return oil pipe is folded downward to expose the observation hole. The presence of hydraulic oil in the return oil pipe is determined through the observation hole. The presence of hydraulic oil in the return oil pipe indicates oil seal leakage. This allows for the determination of whether there is hydraulic oil in the return oil pipe without completely disconnecting the return oil pipe from the connector, facilitating the determination of whether the oil seal is leaking.

[0035] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 is a schematic diagram of a hydraulic system for a forklift provided in an embodiment of this disclosure;

[0039] Figure 2 is an exploded schematic diagram of a connector and return oil pipe provided in an embodiment of this disclosure;

[0040] Figure 3 is a cross-sectional view of an oil return assembly provided in an embodiment of this disclosure;

[0041] Figure 4 is a structural schematic diagram of a forklift device provided in an embodiment of this disclosure;

[0042] Figure 5 is a schematic diagram of the folded state of a folded part provided in an embodiment of this disclosure.

[0043] In the picture:

[0044] 1. Cylinder assembly, 11. Cylinder body, 12. Telescopic shaft, 13. Hydraulic oil pipe;

[0045] 2. Oil return assembly, 21. Connector, 211. Snap-fit ​​hole, 22. Oil return pipe, 221. Snap block, 222. Folding part, 223. Clearance groove, 224. Flexible part, 225. Observation hole, 23. Clamp;

[0046] 3 mast body, 31 moving frame, 32 fork assembly. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions 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, 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.

[0048] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0049] When the hydraulic cylinder of a forklift reaches its highest position, it may drop. This is because there is a problem with the oil seal in the cylinder. In this case, the problem is usually solved by separating the return oil pipe from the connector on the cylinder. If hydraulic oil flows out of the connector, it indicates that there is a problem with the oil seal. However, the relevant technology requires that the return oil pipe be completely disconnected from the connector in order to observe whether there is hydraulic oil flowing out of the connector. The length of the return oil pipe and the connector is relatively long, making it difficult to disassemble the return oil pipe. In addition, due to the harsh working environment of forklifts, when the return oil pipe is disassembled, a large amount of dust from the environment will enter the return oil pipe and cause it to be contaminated.

[0050] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0052] As shown in Figures 1, 2, and 3, at least one disclosed embodiment provides a hydraulic system for a forklift, including: a cylinder assembly 1, with a return oil assembly 2 disposed on the outer wall of the cylinder assembly 1. When the oil seal of the cylinder assembly 1 leaks, the hydraulic oil in the cylinder assembly 1 enters the return oil assembly 2. The presence of hydraulic oil in the return oil assembly 2 is used to determine whether the oil seal is leaking. The presence of hydraulic oil in the return oil assembly 2 indicates that the oil seal is leaking. The return oil assembly 2 includes: a connector 21 and a return oil pipe 22. The connector 21 is connected to the side wall of the cylinder assembly 1. The return oil pipe 22 is sleeved on the bottom of the connector 21, and the side wall of the connector 21 has a plurality of snap-fit ​​holes 21. 1. The inner wall of the return oil pipe 22 is provided with a locking block 221 corresponding to the locking hole 211. When the locking block 221 is inserted into the corresponding locking hole 211, there is an observation hole 225 between the top surface of the locking block 221 and the inner top surface of the locking hole 211. When it is necessary to determine whether the oil seal is leaking, the folded part 222 connected to the end of the return oil pipe 22 is folded down to expose the observation hole 225. The presence of hydraulic oil in the return oil pipe 22 is determined through the observation hole 225. When hydraulic oil is present in the return oil pipe 22, the oil seal is determined to be leaking. This allows it to be determined whether there is hydraulic oil in the return oil pipe 22 without completely disconnecting the return oil pipe 22 from the connector 21, which is convenient for determining whether the oil seal is leaking.

[0053] In this embodiment, by providing a folding part 222 at the end of the return oil pipe 22, the folding part 222 is sleeved on the outside of the connector 21 during the operation of the forklift hydraulic system, thus blocking the observation hole 225 between the locking block 221 and the locking hole 211, preventing dust from the environment from entering the return oil pipe 22. When it is necessary to determine whether there is hydraulic oil in the return oil pipe 22, the folding part 222 can be folded downwards, exposing the observation hole 225 between the locking block 221 and the locking hole 211. At this time, the presence of hydraulic oil in the return oil pipe 22 can be observed through the observation hole 225 by means of manual means. Compared with the traditional method of pulling the entire return oil pipe 22 off the connector 21, the operation of folding the folding part 222 is less difficult and makes it easier to observe the inside of the return oil pipe 22.

[0054] In this embodiment, if there is hydraulic oil in the return oil pipe 22, and it is necessary to completely remove the return oil pipe 22 from the connector 21, since the folding part 222 is already in a downward folded state, only a small part of the return oil pipe 22 is fitted onto the connector 21. At this time, removing the return oil pipe 22 only requires overcoming a small amount of friction. When the traditional return oil pipe 22 is fitted onto the connector 21, it is necessary to overcome a large amount of friction when removing the return oil pipe 22, since a long part of the return oil pipe 22 is fitted onto the connector 21. Therefore, by setting the folding part 222, it is more convenient to remove the return oil pipe 22.

[0055] In this embodiment, since the traditional return oil pipe 22 has a long section that is sleeved on the connector 21, when the return oil pipe 22 is pulled out, dust and other impurities on a long section of the outer wall of the connector 21 will be scraped into the return oil pipe 22. However, in this embodiment, by setting the folding part 222, the length of the outer wall of the connector 21 scraped off when the return oil pipe 22 is pulled out is reduced, thus reducing the entry of dust and other impurities into the return oil pipe 22.

[0056] As shown in Figure 3, in one optional embodiment, a folding clearance groove 223 is provided on the outer wall of the folding part 222 near the end of the return oil pipe 22; the connection position between the folding part 222 and the end of the return oil pipe 22 corresponds to the observation hole 225; when the return oil pipe 22 is sleeved on the bottom of the connector 21, the folding part 222 is sleeved on the outside of the connector 21 to cover the observation hole 225.

[0057] In this embodiment, a clearance groove 223 is provided near the connection position between the folding part 222 and the return oil pipe 22 to facilitate the downward folding of the folding part 222.

[0058] As shown in Figures 3 and 5, in one optional embodiment, the return oil pipe 22 is provided with a flexible part 224. When the folded part 222 folds down and contacts the flexible part 224, a clamp 23 is provided outside the folded part 222 to squeeze the folded part 222 and the flexible part 224, so that the flexible part 224 contracts inward to contact the inner wall, thereby reducing the inner diameter of the return oil pipe 22. If there is hydraulic oil in the return oil pipe 22, the reduced inner diameter of the return oil pipe 22 will hinder the flow of hydraulic oil.

[0059] In this embodiment, both the return oil pipe 22 and the flexible part 224 can be made of rubber. The flexible part 224 can be made of rubber with a smaller thickness than the outer wall of the return oil pipe 22, so that after the folded part 222 is folded and fitted with the clamp 23, the flexible part 224 can be squeezed better, reducing the inner diameter of the flexible part 224. If there is hydraulic oil flowing through the inside of the return oil pipe 22, the hydraulic oil will accumulate because the flexible part 224 is squeezed to the inner wall and obstructs the flow of hydraulic oil. At this time, the presence of hydraulic oil can be better and more accurately determined through the observation hole 225 of the locking block 221 and the locking hole 211.

[0060] In this embodiment, if the oil seal is in a leaking state, hydraulic oil flows inside the connector 21, and the flow direction is shown as F in Figure 3.

[0061] In one optional embodiment, when the folded part 222 is fitted over the connector 21, the folded part 222 is clamped by the clamp 23; the inner bottom surface of the snap-fit ​​hole 211 is inclined, and the bottom surface of the snap-fit ​​block 221 is also inclined, so that when the snap-fit ​​block 221 extends into the snap-fit ​​hole 211, the bottom surface of the snap-fit ​​block 221 contacts the inner bottom surface of the snap-fit ​​hole 211; the snap-fit ​​block 221 is made of flexible material.

[0062] In this embodiment, when the folded part 222 is not folded, a clamp 23 is provided on its outside, which can make the folded part 222 better connected with the connector 21 and prevent the return oil pipe 22 from detaching from the connector 21.

[0063] In this embodiment, the bottom surface of the locking block 221 and the bottom surface of the locking hole 211 are both inclined, which makes it easier to remove the return oil pipe 22.

[0064] In this embodiment, when the return oil pipe 22 is sleeved on the connector 21, the flexible part 224 is not sleeved outside the connector 21. After the folded part 222 is folded down and the clamp 23 is sleeved, the flexible part 224 can be squeezed more conveniently.

[0065] In one alternative embodiment, when it is necessary to remove the return oil pipe 22 from the connector 21, the folding part 222 is in a downward folded state. A clamp 23 is provided outside the folding part 222 to squeeze the folding part 222 and the flexible part 224, so that the flexible part 224 contracts inward to reduce the inner diameter of the return oil pipe 22. Then the return oil pipe 22 is removed from the connector 21.

[0066] In this embodiment, when the return oil pipe 22 needs to be disconnected, the folded part 222 is in a downward folded state, and at this time the clamp 23 squeezes the flexible part 224, so that the inner wall of the flexible part 224 is in contact when the return oil pipe 22 is disconnected, thereby reducing the possibility of dust and impurities in the environment entering the return oil pipe 22.

[0067] As shown in Figure 1, in one optional embodiment, the hydraulic cylinder assembly 1 includes: a cylinder body 11 and a telescopic shaft 12; the telescopic shaft 12 is slidably disposed within the cylinder body 11, and the top end of the telescopic shaft 12 extends from the top end of the cylinder body 11; an oil seal is provided between the outer wall of the telescopic shaft 12 and the inner wall of the cylinder body 11; the connector 21 is connected to the outer wall of the cylinder body 11 and communicates with the interior of the cylinder body 11, and the communication position is close to the top of the cylinder body 11.

[0068] As shown in Figure 1, in one optional embodiment, a hydraulic oil pipe 13 is provided on the side wall of the cylinder 11 near the bottom of the cylinder 11. When the telescopic shaft 12 needs to rise, hydraulic oil is introduced through the hydraulic oil pipe 13 between the inner bottom surface of the cylinder 11 and the bottom of the telescopic shaft 12 to drive the telescopic shaft 12 to move upward.

[0069] In this embodiment, the other end of the hydraulic oil pipe 13 can be connected to an oil pump or the like.

[0070] In this embodiment, there is a space between the inner bottom surface of the cylinder 11 and the telescopic shaft 12. The hydraulic oil pipe 13 is connected to this space, allowing hydraulic oil to enter the space. When the telescopic shaft 12 needs to move downward, the oil pump connected to the hydraulic oil pipe 13 stops pumping hydraulic oil. At this time, the gravity provided by the other devices or mechanisms on the forklift connected to the telescopic shaft 12 causes the telescopic shaft 12 to move downward.

[0071] As shown in Figure 4, at least one other disclosed embodiment also provides a fork device using the above-described hydraulic system for forklifts, including: a mast body 3 and a movable frame 31 slidably connected to the mast body 3. The cylinder assembly 1 in the hydraulic system for forklifts is connected to the mast body 3, and the telescopic shaft 12 in the cylinder assembly 1 is connected to the movable frame 31 to drive the movable frame 31 to move up and down along the mast body 3. A fork assembly 32 is provided on the movable frame 31.

[0072] At least one other disclosed embodiment also provides a forklift including the above-described fork assembly.

[0073] At least one other disclosed embodiment also provides a method for judging the leakage of hydraulic oil in the above-described hydraulic system for forklifts, comprising: when the oil seal of the cylinder assembly 1 leaks, the hydraulic oil in the cylinder assembly 1 enters the return oil assembly 2, and the oil seal is judged to be leaking when there is hydraulic oil in the return oil assembly 2; when it is necessary to judge whether the oil seal is leaking, the folded part 222 connected to the end of the return oil pipe 22 is folded downward to expose the observation hole 225, and the presence of hydraulic oil in the return oil pipe 22 is judged through the observation hole 225.

[0074] In summary, the hydraulic system for this forklift includes: a cylinder assembly 1, with a return oil assembly 2 installed on the outer wall of the cylinder assembly 1. When the oil seal of the cylinder assembly 1 leaks, the hydraulic oil inside the cylinder assembly 1 enters the return oil assembly 2, thus determining the oil seal leak when hydraulic oil is present in the return oil assembly 2. The return oil assembly 2 includes: a connector 21 and a return oil pipe 22. The connector 21 is connected to the side wall of the cylinder assembly 1. The return oil pipe 22 is sleeved on the bottom of the connector 21. The side wall of the connector 21 has several snap-fit ​​holes 211, and the inner wall of the return oil pipe 22 is provided with a fitting that aligns with the snap-fit ​​holes 211. The corresponding locking block 221, when inserted into the corresponding locking hole 211, has an observation hole 225 between its top surface and the inner top surface of the locking hole 211; when it is necessary to determine whether the oil seal is leaking, the folded part 222 connected to the end of the return oil pipe 22 is folded downwards to expose the observation hole 225. The presence of hydraulic oil in the return oil pipe 22 is determined through the observation hole 225. When hydraulic oil is present in the return oil pipe 22, the oil seal is determined to be leaking. This allows it to be determined whether there is hydraulic oil in the return oil pipe 22 without completely disconnecting it from the connector 21, which is convenient for determining whether the oil seal is leaking.

[0075] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0076] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence unless expressly indicated herein. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed above may be referred to as a second element, component, region, layer, or segment.

[0077] Spatially relative terms, such as “inside,” “outside,” “below,” “below,” “down,” “above,” “up,” etc., may be used herein to describe the relationship between one element or feature illustrated in the figures and another element or feature. In addition to the orientations depicted in the figures, spatially relative terms may be intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, an element described as “below” or “below” other elements or features would be oriented as “above” other elements or features. Thus, the example term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly.

[0078] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A hydraulic system for forklifts, characterized in that, include: A hydraulic cylinder assembly (1) has a return oil assembly (2) on its outer wall. When the oil seal of the hydraulic cylinder assembly (1) leaks, the hydraulic oil in the hydraulic cylinder assembly (1) enters the return oil assembly (2), and the presence of hydraulic oil in the return oil assembly (2) indicates that the oil seal is leaking. The return oil assembly (2) includes a connector (21) and a return oil pipe (22). The connector (21) is connected to the side wall of the hydraulic cylinder assembly (1). The return oil pipe (22) is sleeved on the bottom of the connector (21), and the side wall of the connector (21) has several snap-fit ​​holes (211). The inner wall of the return oil pipe (22) is provided with a locking block (221) corresponding to the locking hole (211). When the locking block (221) is inserted into the corresponding locking hole (211), there is an observation hole (225) between the top surface of the locking block (221) and the inner top surface of the locking hole (211). When it is necessary to determine whether the oil seal is leaking, the folded part (222) connected to the end of the return oil pipe (22) is folded down so that the observation hole (225) is exposed. The presence of hydraulic oil in the return oil pipe (22) is determined by the observation hole (225). When hydraulic oil is present in the return oil pipe (22), the oil seal is determined to be leaking.

2. The hydraulic system for forklifts as described in claim 1, characterized in that, The outer wall of the folding part (222) is provided with a folding clearance groove (223) near the end of the return oil pipe (22); the connection position of the folding part (222) and the end of the return oil pipe (22) corresponds to the observation hole (225); when the return oil pipe (22) is sleeved on the bottom of the connector (21), the folding part (222) is sleeved on the outside of the connector (21) to cover the observation hole (225).

3. The hydraulic system for forklifts as described in claim 2, characterized in that, The return oil pipe (22) is provided with a flexible part (224); when the folded part (222) folds down and comes into contact with the flexible part (224), a clamp (23) is provided outside the folded part (222) to squeeze the folded part (222) and the flexible part (224), so that the flexible part (224) shrinks inward to contact the inner wall, thereby reducing the inner diameter of the return oil pipe (22). If there is hydraulic oil in the return oil pipe (22), the inner diameter of the return oil pipe (22) will decrease and hinder the flow of hydraulic oil.

4. The hydraulic system for forklifts as described in claim 2, characterized in that, When the folded part (222) is fitted outside the joint (21), the folded part (222) is tightened by the clamp (23); the inner bottom surface of the snap-fit ​​hole (211) is inclined, and the bottom surface of the snap-fit ​​block (221) is also inclined. When the snap-fit ​​block (221) extends into the snap-fit ​​hole (211), the bottom surface of the snap-fit ​​block (221) contacts the inner bottom surface of the snap-fit ​​hole (211); the snap-fit ​​block (221) is made of flexible material.

5. The hydraulic system for forklifts as described in claim 3, characterized in that, When it is necessary to remove the return oil pipe (22) from the connector (21), the folding part (222) is in a downward folding state. A clamp (23) is set outside the folding part (222) to squeeze the folding part (222) and the flexible part (224), so that the flexible part (224) shrinks inward to reduce the inner diameter of the return oil pipe (22). Then the return oil pipe (22) is removed from the connector (21).

6. The hydraulic system for forklifts as described in claim 2, characterized in that, The hydraulic cylinder assembly (1) includes: a cylinder body (11) and a telescopic shaft (12); the telescopic shaft (12) is slidably disposed inside the cylinder body (11), and the top end of the telescopic shaft (12) extends from the top end of the cylinder body (11); an oil seal is provided between the outer wall of the telescopic shaft (12) and the inner wall of the cylinder body (11); the connector (21) is connected to the outer wall of the cylinder body (11) and communicates with the inside of the cylinder body (11), and the communication position is close to the top of the cylinder body (11).

7. The hydraulic system for forklifts as described in claim 6, characterized in that, A hydraulic oil pipe (13) is provided on the side wall of the cylinder (11) near the bottom of the cylinder (11). When the telescopic shaft (12) needs to rise, hydraulic oil is introduced through the hydraulic oil pipe (13) between the bottom surface of the cylinder (11) and the bottom of the telescopic shaft (12) to drive the telescopic shaft (12) to move upward.

8. A fork assembly employing the hydraulic system for forklifts as described in claim 1, characterized in that, include: The mast body (3) and the movable frame (31) slidably connected to the mast body (3) are provided. The cylinder assembly (1) in the hydraulic system of the forklift is connected to the mast body (3). The telescopic shaft (12) in the cylinder assembly (1) is connected to the movable frame (31) to drive the movable frame (31) to move up and down along the mast body (3). The movable frame (31) is provided with a fork assembly (32).

9. A forklift, characterized in that, include: The forklift device as described in claim 8.

10. A method for determining hydraulic oil leakage in a forklift hydraulic system as described in claim 1, characterized in that, include: When the oil seal of the cylinder assembly (1) leaks, the hydraulic oil in the cylinder assembly (1) enters the return oil assembly (2), and the oil seal is judged to be leaking when there is hydraulic oil in the return oil assembly (2). When it is necessary to judge whether the oil seal is leaking, the folding part (222) connected to the end of the return oil pipe (22) is folded down to expose the observation hole (225), and the presence of hydraulic oil in the return oil pipe (22) is judged through the observation hole (225).

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