Unloading mechanism with stroke limit and engineering machinery
Patent Information
- Application Number
- CN202522289726.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-29
- Publication Date
- 2026-10-13
- Estimated Expiration
- 2035-10-29
AI Technical Summary
[0003]目前现有的行程限位卸荷阀普遍存在以下缺点：采用电子传感器实现开关卸荷，成本和技术复杂度显著增加，传感器本身和电路系统需要定期检查维护甚至更换，长期使用成本高；电子传感器受电磁干扰、灰尘、油污或极端温度影响可能会导致误触发或失效，可靠性低；安装调试复杂，对于技术人员、安装人员以及售后人员的要求都比较高，执行难度较大
[0035]本实用新型不采用电磁阀控制或者液控的方式，加工成本低廉，只要执行机构达到行程就可推动推杆，油路即可打开实现卸荷，该结构紧凑也可以有效的减少安装空间；整阀采用纯机械的控制方式，通过控制推杆即可实现主阀芯换向实现主级启闭功能，在潮湿、高温或者粉尘等恶劣的工况下仍能快速响应，安全可靠；零部件维修处理仅需拆卸螺钉和堵头即可，维修方便大大降低了维护成本；通过控制推杆即可实现主阀芯换向实现主级启闭功能，在油缸超出预设行程时可以立即卸荷，有效的保护执行机构和系统。
Smart Images
Figure CN224850037U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of excavators, specifically relating to an unloading mechanism with a travel limit and engineering machinery. Background Technology
[0002] In construction machinery, stroke limit unloading mechanisms are widely used in lifting equipment, excavators, loaders, aerial work platforms, concrete pump trucks and other fields. They are key components in hydraulic systems, effectively protecting the hydraulic system, preventing equipment damage or safety accidents caused by overtravel, and extending the life of the actuator and the main unit.
[0003] Currently available travel limit unloading valves generally have the following drawbacks: using electronic sensors to achieve switching and unloading significantly increases cost and technical complexity; the sensors themselves and the circuit system require regular inspection, maintenance, and even replacement, resulting in high long-term operating costs; electronic sensors are susceptible to electromagnetic interference, dust, oil, or extreme temperatures, which may lead to false triggering or failure, resulting in low reliability; installation and commissioning are complex, requiring highly skilled technicians, installers, and after-sales personnel, making execution difficult.
[0004] To address the aforementioned issues, this invention provides an unloading mechanism with a stroke limit switch. When the actuator reaches the set or maximum stroke, causing abnormal system pressure, the hydraulic pump output oil is directly returned to the oil tank or other oil circuits via the unloading oil circuit, thereby reducing energy loss and extending the service life of the pump and system. Utility Model Content
[0005] To address the aforementioned problems, this utility model proposes an unloading mechanism and engineering machinery with a stroke limit, which can reduce the manufacturing cost and technical complexity of the unloading mechanism, extend its service life, and improve its reliability.
[0006] To achieve the above-mentioned technical objectives and effects, this utility model is implemented through the following technical solution:
[0007] In a first aspect, this application provides an unloading mechanism with a travel limit switch, comprising:
[0008] The valve body has a first inner hole along its axial direction and a second end with an assembly hole that communicates with the first inner hole.
[0009] The valve core is disposed in the first inner hole, and a second inner hole is provided inside it along its axial direction.
[0010] Oil return port B is connected to the first inner hole through the first oil passage;
[0011] A plug is provided inside the assembly hole;
[0012] One end of the spring is installed in the second inner hole, and the other end is connected to the plug;
[0013] The valve sleeve is connected to the first end of the valve core and communicates with the first inner hole;
[0014] The push rod is slidably disposed inside the valve sleeve and is used to move the valve core within the first inner hole. A second oil passage is provided inside the push rod along its axial direction.
[0015] Oil inlet A is connected to the second oil passage.
[0016] The above technical solution uses only springs, push rods, and plugs to disconnect the oil circuit between the valve core and the valve body, thereby achieving unloading. It has low processing costs and a compact structure. The entire valve body adopts a purely mechanical control method, which facilitates disassembly and maintenance and enhances the reliability and service life of the entire mechanism.
[0017] Optionally, the valve core and the first oil passage are in conical contact.
[0018] The above technical solution uses a conical surface contact between the valve core and the first oil passage to make the gap between the valve core and the first oil passage variable. As the valve core moves, the size of the gap changes synchronously, thereby achieving on / off control of the oil circuit. Furthermore, the use of conical surface contact can better achieve a sealing effect and reduce internal leakage.
[0019] Optionally, when the valve core does not reverse direction, the push rod does not move, the cross-sectional area of the right cavity of the valve core is larger than the cross-sectional area of the left cavity, the conical contact point between the valve core and the first oil passage is always unable to open, and the passage between the valve core and the return oil port is cut off.
[0020] In the above technical solution, under the initial state of spring force, the end of the valve core away from the second inner hole contacts the push rod, and the passage between the valve core and the oil return port B is cut off by the conical surface, so that the oil circuit cannot be unloaded.
[0021] Optionally, the main system oil passes through inlet A, then through the push rod and valve core to the left and right chambers of the valve core. At this time, the oil circuit between inlet A and return port B is not connected, and the oil circuit cannot be unloaded.
[0022] In the above technical solution, because the oil passage is blocked, the oil passing through the oil inlet A is not unloaded. At the same time, the spring cavity area of the valve core is larger than the push rod drive cavity area. Under the action of the spring, the conical contact point between the valve core and the oil port B cannot be opened, and the oil in the main system cannot be unloaded.
[0023] Optionally, when the valve core reverses direction, the push rod pushes the valve core to move towards the end closer to the plug, the conical contact point between the valve core and the first oil passage is opened, and the valve core is connected to the return port B.
[0024] In the above technical solution, when the actuator pushes the push rod, the push rod pushes the valve core to move to the right. As long as the actuator reaches its stroke, it can push the push rod to open the oil circuit and achieve unloading. The operation is convenient and quick, improving the response speed. The compact structure can also effectively reduce the installation space.
[0025] Optionally, the main system oil passes through inlet A, then through the push rod mechanism and valve core to reach the left and right chambers of the valve core. At this time, the oil circuit of inlet A and return port B is connected, and the oil circuit is in an unloaded state.
[0026] The above technical solution allows the oil to flow smoothly to the return port B when the oil passages of port A and return port B are connected, thus achieving unloading. The entire structure is simple and efficient, reducing costs and maintenance difficulty.
[0027] Optionally, the unloading mechanism with stroke limit further includes a screw plug, wherein the valve body surface is provided with a spare oil port, and the screw plug is used to seal the spare oil port.
[0028] The above technical solution has a spare oil port reserved on the side of the valve body, which is normally sealed with a screw plug. When the main system needs to change the connection oil circuit of the return oil port B, the screw plug can be removed to achieve the oil priming function.
[0029] Optionally, the unloading mechanism with stroke limit further includes: a first O-ring, which is installed on the mating surface of the first inner hole that contacts the valve core.
[0030] In the above technical solution, the first O-ring is used for sealing to prevent oil leakage.
[0031] Optionally, the unloading mechanism with stroke limit further includes a second O-ring, which is disposed between the valve body and the connector.
[0032] In the above technical solution, the second O-ring is placed between the valve body and the connector to prevent oil leakage at the connection.
[0033] Secondly, this application also provides an engineering machinery, including the unloading mechanism with travel limit as described in any of the above claims.
[0034] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0035] This invention does not employ solenoid valve control or hydraulic control, resulting in low processing costs. The actuator only needs to reach its stroke to push the push rod, opening the oil circuit and achieving unloading. Its compact structure also effectively reduces installation space. The entire valve uses a purely mechanical control method; controlling the push rod allows for the main valve core to switch direction, achieving the main stage opening and closing function. It maintains rapid response and reliability even in harsh conditions such as humidity, high temperature, or dust. Component maintenance only requires disassembling screws and plugs, greatly reducing maintenance costs. Controlling the push rod allows for the main valve core to switch direction, achieving the main stage opening and closing function. When the cylinder exceeds its preset stroke, it can immediately unload, effectively protecting the actuator and the system.
[0036] Meanwhile, this utility model can be applied to fields such as lifting equipment, excavators, loaders, aerial work platforms, and concrete pump trucks that require setting specific strokes to prevent danger; by changing the connection oil circuit of return oil port B, the oil priming function can also be realized, making it more ingenious to work in coordination with the main system. Attached Figure Description
[0037] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:
[0038] Figure 1 This is a schematic diagram of the overall structure of an unloading mechanism with a stroke limit according to the present invention;
[0039] Figure 2 This is a schematic diagram of the unloading mechanism of this utility model in the state where the push rod is not pushed to change direction according to an embodiment of the present utility model;
[0040] Figure 3 This is a schematic diagram of the unloading mechanism pushing the push rod to change direction according to an embodiment of the present invention;
[0041] Wherein: 1-valve body, 2-valve core, 3-first O-ring, 4-spring, 5-push rod, 6-valve sleeve, 7-second O-ring, 8-screw plug, 9-plug. Detailed Implementation
[0042] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the scope of protection of this utility model.
[0043] In the description of this utility model patent, it should be noted that the terms "upper", "lower", "left", "right", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model patent 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. Therefore, they should not be construed as limitations on this utility model patent.
[0044] In the description of this utility model patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 this utility model based on the specific circumstances.
[0045] The application principle of this utility model will be described in detail below with reference to the accompanying drawings.
[0046] Example 1
[0047] like Figure 1 As shown, this embodiment provides an unloading mechanism with a stroke limit, including:
[0048] The valve body 1 has a first inner hole along its axial direction and a second end of it has an assembly hole that communicates with the first inner hole.
[0049] Valve core 2 is disposed in the first inner hole, and a second inner hole is provided inside it along its axial direction;
[0050] Oil return port B is connected to the first inner hole through the first oil passage;
[0051] A plug is provided inside the assembly hole;
[0052] Spring 4, one end is installed in the second inner hole, and the other end is connected to the plug 9;
[0053] Valve sleeve 6 is connected to the first end of valve core 2 and communicates with the first inner hole;
[0054] Push rod 5 is slidably disposed in valve sleeve 6 and is used to move the valve core 2 in the first inner hole. A second oil passage is provided inside the push rod along its axial direction.
[0055] Oil inlet A is connected to the second oil passage.
[0056] In the initial state of the above technical solution, under the action of spring force, the end of the valve core 2 away from the second inner hole is in contact with the push rod 5 and is separated from the plug 9. When the valve core 2 reverses direction, the end closer to the second inner hole contacts the plug 9, which can act as a limit stop. The plug 9 is installed at the threaded hole of the valve body 1 and can also be used for sealing. The oil return port B is always connected back to the oil tank or the oil circuit that needs to be replenished. This solution does not use solenoid valve control or hydraulic control, resulting in low processing costs. As long as the actuator reaches its stroke, it can push the push rod 5, opening the oil circuit to achieve unloading. This compact structure can also effectively reduce installation space and can still respond quickly and reliably under harsh working conditions such as humidity, high temperature, or dust.
[0057] In one specific implementation of this embodiment, such as Figure 1 As shown, the valve core 2 and the first oil passage are in conical contact.
[0058] In one specific implementation of this embodiment, such as Figure 2 As shown, when the valve core 2 does not reverse, the push rod 5 does not move, the cross-sectional area of the right cavity of the valve core 2 is larger than the cross-sectional area of the left cavity, the conical contact point between the valve core 2 and the first oil passage can never be opened, and the passage between the valve core 2 and the return oil port is cut off.
[0059] In the above technical solution, when the unloading mechanism is in the initial state, the actuator does not push the push rod 5, and the valve core 2 does not change direction. At this time, the spring cavity area of the valve core 2 is larger than the push rod drive cavity area. Under the action of the spring 4, the passage between the valve core 2 and the return oil port B is cut off by the conical surface, and the oil passage between the oil inlet A and the return oil port B is not connected.
[0060] In one specific implementation of this embodiment, such as Figure 2 As shown, the main system oil passes through the oil inlet A, and then through the push rod 5 and the valve core 2 to reach the left and right chambers of the valve core 2. At this time, the oil circuit between the oil inlet A and the oil return port B is not connected, and the oil circuit cannot be unloaded.
[0061] In the above technical solution, when the actuator does not push the push rod 5 and the valve core 2 does not reverse, the valve core 2 is placed at the leftmost end of the first inner hole in the valve body 1. The passage between the valve core 2 and the return port B is cut off by the conical surface. At this time, the oil circuit is blocked. Since the working position has not been reached, the unloading oil circuit does not unload. The main system oil circuit passes through the inlet A, through the push rod 5 and the valve core 2 to reach the spring cavity and push rod drive cavity of the valve core 2. Because the oil circuit is blocked, the oil passing through the inlet A is not unloaded. At the same time, the area of the spring cavity of the valve core 2 is larger than the area of the push rod drive cavity. Under the action of the spring 4, the contact point between the valve core 2 and the conical surface of the oil port B cannot be opened. The main system oil cannot be unloaded. At this time, the system is in the normal working position.
[0062] In one specific implementation of this embodiment, such as Figure 3As shown, when the valve core 2 reverses direction, the push rod 5 pushes the valve core 2 to move towards the end closer to the plug 9, the conical contact point between the valve core and the first oil passage is opened, and the valve core 2 is connected to the return port B.
[0063] In the above technical solution, when the valve core 2 reverses direction, the actuator pushes the push rod 5, and the push rod 5 pushes the valve core 2 to move towards the end closer to the plug 9. At this time, the spring cavity area of the valve core 2 is smaller than the push rod drive cavity area, the conical connection between the valve core 2 and the return oil port B is opened, and the oil passage between the oil inlet A and the return oil port B is connected. Unloading is achieved only through displacement, that is, stroke limit, which is simple to operate and highly reliable.
[0064] In one specific implementation of this embodiment, such as Figure 3 As shown, the main system oil passes through the oil inlet A, and then through the push rod mechanism 5 and the valve core 2 to reach the left and right chambers of the valve core 2. At this time, the oil inlet A and the oil return port B are connected, and the oil circuit is in an unloaded state.
[0065] In the above technical solution, when the actuator pushes the push rod 5 and the valve core 2 reverses direction, the valve core 2 moves to the right in the first inner hole. The system oil passes through the oil inlet A, through the push rod 5 and the valve core 2 to reach the spring cavity and push rod drive cavity of the valve core. Because the actuator has already pushed the push rod 5 at this time, the conical connection between the valve core 2 and the return oil port B is opened, and the oil circuit between the oil inlet A and the return oil port B is connected. At this time, the oil circuit is in an unloaded state. The pure mechanical unloading method has a very simple structure, reduces costs and maintenance difficulty, and has strong environmental adaptability, and can withstand harsh working conditions. This utility model can effectively control the extension length of the actuator. When unloading occurs, both the actuator and the main system are protected.
[0066] In one specific embodiment of this example, the unloading mechanism with travel limit further includes:
[0067] The first O-ring 3 is installed on the mating surface of the first inner hole that contacts the valve core 2.
[0068] In the above technical solution, the first O-ring is located between the valve body 1 and the valve core 3 to seal and prevent oil leakage.
[0069] In one specific embodiment of this example, the unloading mechanism with travel limit further includes:
[0070] The second O-ring 7 is disposed between the valve body 1 and the connector.
[0071] In the above technical solution, the second O-ring is placed between the valve body 1 and the connector to prevent oil leakage at the connection, and provides a certain shock absorption effect while ensuring a seal.
[0072] Example 2
[0073] Based on Embodiment 1, the difference between this embodiment and Embodiment 1 is that this embodiment also includes a screw plug 8, and the valve body 1 has a spare oil port on its surface. The screw plug 8 is used to seal the spare oil port. In specific implementation, if the return oil port is connected to other bypasses, it can also serve as a diversion function during unloading.
[0074] Example 3
[0075] This invention provides an engineering machinery, including the unloading mechanism with stroke limit as described in embodiment 1 or 2.
[0076] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A loading unloading mechanism with stroke limit, characterized in that, include: The valve body (1) has a first inner hole along its axial direction and an assembly hole connected to the first inner hole at its second end. Valve core (2) is located in the first inner hole, and a second inner hole is provided inside it along its axial direction; Oil return port B is connected to the first inner hole through the first oil passage; A plug is provided inside the assembly hole; One end of the spring (4) is installed in the second inner hole, and the other end is connected to the plug (9); The valve sleeve (6) is connected to the first end of the valve core (2) and communicates with the first inner hole; The push rod (5) is slidably disposed in the valve sleeve (6) and is used to act on the valve core (2) to move in the first inner hole. A second oil passage is provided inside the push rod along its axial direction. Oil inlet A is connected to the second oil passage.
2. The unloading mechanism with stroke limit according to claim 1, characterized in that, The valve core (2) and the first oil passage are in conical contact.
3. The unloading mechanism with stroke limit according to claim 2, characterized in that, When the valve core (2) does not change direction, the push rod (5) does not move, the cross-sectional area of the right cavity of the valve core (2) is greater than the cross-sectional area of the left cavity, the conical contact point between the valve core (2) and the first oil passage is always unable to open, and the passage between the valve core (2) and the return oil port is cut off.
4. The unloading mechanism with stroke limit according to claim 3, characterized in that, The main system oil passes through the oil inlet A, and then through the push rod (5) and the valve core (2) to reach the left and right chambers of the valve core (2). At this time, the oil circuit between the oil inlet A and the return oil port B is not connected, and the oil circuit cannot be unloaded.
5. The unloading mechanism with stroke limit according to claim 2, characterized in that, When the valve core (2) reverses direction, the push rod (5) pushes the valve core (2) to move towards the end closer to the plug (9), the conical contact point between the valve core and the first oil passage is opened, and the valve core (2) is connected to the return port B.
6. The unloading mechanism with stroke limit according to claim 5, characterized in that, The main system oil passes through the oil inlet A, and then through the push rod (5) and the valve core (2) to reach the left and right chambers of the valve core (2). At this time, the oil inlet A and the oil return port B are connected, and the oil circuit is in an unloaded state.
7. The unloading mechanism with stroke limit according to claim 1, characterized in that, The unloading mechanism with stroke limit also includes a screw plug (8), and the valve body (1) has a spare oil port on its surface. The screw plug (8) is used to seal the spare oil port.
8. The unloading mechanism with stroke limit according to claim 1, characterized in that, The unloading mechanism with travel limit also includes: The first O-ring (3) is installed on the mating surface of the first inner hole that contacts the valve core (2).
9. The unloading mechanism with stroke limit according to claim 1, characterized in that, The unloading mechanism with travel limit also includes: The second O-ring (7) is located between the valve body (1) and the valve sleeve (6).
10. An engineering machinery, characterized in that... The unloading mechanism with travel limit as described in any one of claims 1-9.