Counterweight oil cylinder with displacement detection function, hydraulic system and crane

Abstract

The invention discloses a counterweight oil cylinder with a displacement detection function, a hydraulic system and a crane. The counterweight oil cylinder with the displacement detection function comprises a piston rod; the piston is mounted at one end of the piston rod and is in sliding connection with the cylinder body; the detection rod is kept static relative to the cylinder body; the detection magnetic ring synchronously moves along with the piston rod; the detection rod is sleeved with the detection magnetic ring, and the detection magnetic ring is connected with the detection rod in a sliding mode, so that a displacement sensor used for detecting the relative position relation of the piston rod and the cylinder body is formed. Displacement of the counterweight oil cylinder can be mastered in real time, impact vibration caused in the ascending and descending process of the counterweight can be relieved, meanwhile, when the counterweight oil cylinder abnormally descends, an alarm signal can be received in time, and therefore safety accidents can be avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of cranes, and in particular relates to a counterweight oil cylinder with displacement detection, a hydraulic system and a crane. Background Art

[0002] With the rapid development of economic construction, construction machinery, especially cranes, are increasingly used in various fields of economic construction. In order to achieve a higher lifting capacity of the crane, it is usually necessary to add a counterweight block to the tail of the crane to achieve torque balance.

[0003] Large-tonnage cranes often have a large counterweight, which is typically removed from the crane during transfers and transported separately. Once at the worksite, it's attached to the crane's turntable based on the tonnage of the cargo being hoisted. Due to limited visibility in the operator's cab, the counterweight's movement must be controlled remotely via a remote control.

[0004] During the counterweight raising and lowering process, the hydraulic power comes from a gear pump connected to the engine's power take-off port, with the output flow rate dependent on engine speed. Currently, for fuel economy, counterweight raising and lowering operations are performed at engine idle speed. Frequent changes in engine speed can cause fluctuations in hydraulic system flow, leading to unstable operation of the counterweight cylinder and potentially causing shock and vibration to the vehicle.

[0005] When the counterweight is hung at the highest position for a long time, the cylinder piston rod may extend due to leakage in the counterweight cylinder or other factors, causing the counterweight to drop. Since there is no displacement detection function for the counterweight and no alarm can be issued to the operator, the vehicle may easily roll over. Summary of the Invention

[0006] To address the deficiencies in the prior art, the present invention provides a counterweight cylinder, a hydraulic system, and a crane with displacement detection, which can monitor the displacement of the counterweight cylinder in real time and reduce the impact and vibration caused by the rising and falling of the counterweight. At the same time, when the counterweight cylinder falls abnormally, an alarm signal can be received in time to avoid the occurrence of safety accidents.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: In the first aspect, a counterweight cylinder with displacement detection is provided, comprising: a piston rod; a piston installed at one end of the piston rod, the piston being slidably connected to the cylinder body; a detection rod that remains relatively stationary with the cylinder body; a detection magnetic ring that moves synchronously with the piston rod; the detection magnetic ring is sleeved on the detection rod and slidably connected to the detection rod to form a displacement sensor for detecting the relative position relationship between the piston rod and the cylinder body.

[0008] Furthermore, the cylinder body includes a cylinder barrel and a cylinder bottom arranged at one end of the cylinder barrel.

[0009] Furthermore, one end of the detection rod is installed on the cover plate, and the other end passes through the cylinder bottom and is inserted into the reserved hole on the piston rod. The cover plate is installed on the cylinder bottom; the detection magnetic ring is sleeved on the detection rod and embedded in the reserved hole on the piston rod.

[0010] Furthermore, one end of the detection rod is mounted on the outer wall of the cylinder, one end of the piston rod located outside the cylinder is provided with a flange, and the other end of the detection rod is slidably connected to the detection magnetic ring on the piston rod.

[0011] In a second aspect, a hydraulic system is provided, wherein the hydraulic system is equipped with the counterweight cylinder with displacement detection as described in the first aspect.

[0012] Furthermore, the large chamber of the counterweight cylinder is connected to outlet one of the balancing valve, the small chamber of the counterweight cylinder is connected to outlet two of the balancing valve, inlet one of the balancing valve is connected to outlet one of the proportional solenoid valve, inlet two of the balancing valve is connected to outlet two of the proportional solenoid valve, the inlet of the proportional solenoid valve is connected to the oil source, and the oil return port of the proportional solenoid valve is connected to the oil tank; the controller is electrically connected to the displacement sensor of the counterweight cylinder and the control end of the proportional solenoid valve respectively.

[0013] Furthermore, when the counterweight cylinder is controlled to lift, the proportional solenoid valve is switched to the left position, and the hydraulic oil enters the small chamber of the counterweight cylinder through the inlet of the proportional solenoid valve, the outlet 1 of the proportional solenoid valve, the inlet 1 of the balancing valve, and the outlet 2 of the balancing valve; the hydraulic oil in the large chamber of the counterweight cylinder flows into the oil tank through the outlet 1 of the balancing valve, the inlet 2 of the balancing valve, the outlet 2 of the proportional solenoid valve, and the return oil port of the proportional solenoid valve; the controller collects the displacement of the piston rod through the displacement sensor and adjusts the current value of the proportional solenoid valve control end according to the set control logic, so as to reduce the impact vibration generated by the upper surface of the counterweight block and the lower surface of the turntable when the counterweight cylinder is lifted to the limit position.

[0014] Furthermore, when the counterweight cylinder is controlled to fall, the proportional solenoid valve is switched to the right position, and the hydraulic oil enters the large chamber of the counterweight cylinder through the inlet of the proportional solenoid valve, the second outlet of the proportional solenoid valve, the second inlet of the balancing valve, and the first outlet of the balancing valve; the hydraulic oil in the small chamber of the counterweight cylinder flows into the oil tank through the second outlet of the balancing valve, the first inlet of the balancing valve, the first outlet of the proportional solenoid valve, and the return oil port of the proportional solenoid valve; the controller collects the displacement of the piston rod through the displacement sensor and adjusts the current value of the proportional solenoid valve control end according to the set control logic, so as to reduce the impact vibration generated by the counterweight block and the frame when the counterweight cylinder falls to the extreme position.

[0015] Furthermore, when the counterweight cylinder extends abnormally, causing the counterweight block to fall, the displacement sensor transmits the collected piston rod displacement to the controller. When the displacement exceeds the set value, the controller issues an alarm and prompts the operator to lift the counterweight block to the set position again.

[0016] According to a third aspect, a crane is provided, wherein the crane is equipped with the hydraulic system according to the second aspect.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses a counterweight cylinder with displacement detection. The detection rod and the cylinder body remain relatively stationary. The detection magnetic ring moves synchronously with the piston rod. The detection magnetic ring is sleeved on the detection rod and slidably connected to the detection rod to form a displacement sensor for detecting the relative position relationship between the piston rod and the cylinder body. The position of the counterweight block is monitored in real time. When the counterweight block is approaching the highest and lowest positions, the input current of the proportional solenoid valve is reduced by the controller, thereby reducing the flow of the hydraulic system, slowing down the movement speed of the counterweight cylinder, and reducing the impact vibration of the vehicle. (2) In the present invention, when the counterweight block is hung for a long time, if the piston rod of the counterweight cylinder extends abnormally, the displacement sensor can detect the downward movement of the counterweight block. When the downward movement exceeds the set value, the controller will issue an alarm warning to the operator to avoid the occurrence of safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a cross-sectional schematic diagram of a counterweight cylinder with displacement detection provided by an embodiment of the present invention; Figure 2 This is a schematic diagram of the principle of a hydraulic system provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of a counterweight cylinder with displacement detection lifting a counterweight block provided by an embodiment of the present invention; In the figure: 11, bolt 12, cover plate; 13, detection rod; 14, detection magnetic ring; 15, piston rod; 16, cylinder bottom; 17, piston; 18, cylinder barrel; 19, flange; 21, controller; 22, displacement sensor; 23, counterweight cylinder; 24, balancing valve; 25, proportional solenoid valve; 32, upper surface of counterweight block; 33, lower surface of turntable. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] Example 1 like Figures 1 to 3 As shown, a counterweight cylinder with displacement detection includes: a piston rod 15; a piston 17 installed at one end of the piston rod 15, and the piston 17 is slidably connected to the cylinder body; a detection rod 13 that remains relatively stationary with the cylinder body; a detection magnetic ring 14 that moves synchronously with the piston rod 15; the detection magnetic ring 14 is sleeved on the detection rod 13 and slidably connected to the detection rod 13, forming a displacement sensor 22 for detecting the relative position relationship between the piston rod 15 and the cylinder body.

[0021] The cylinder body includes a cylinder barrel 18 and a cylinder bottom 16 disposed at one end of the cylinder barrel 18 .

[0022] One end of the detection rod 13 is installed on the cover plate 12, and the other end passes through the cylinder bottom 16 and is inserted into the reserved hole on the piston rod 15. The cover plate 12 is installed on the cylinder bottom 16 by the bolt 11; the detection magnetic ring 14 is sleeved on the detection rod 13 and embedded in the reserved hole on the piston rod 15.

[0023] During the movement of the counterweight cylinder, the piston rod 15 and the detection rod 13 have relative displacement, so the detection magnetic ring 14 can detect the displacement of the piston rod 15 and convert the displacement into an electrical signal to transmit to the controller 21.

[0024] Example 2 The difference between this embodiment and the first embodiment is that the displacement sensor in the first embodiment is installed inside the counterweight cylinder, while the displacement sensor in this embodiment is installed outside the counterweight cylinder.

[0025] One end of the detection rod 13 is mounted on the outer wall of the cylinder 18 , and a flange 19 is provided on the end of the piston rod 15 outside the cylinder 18 . The other end of the detection rod 13 is slidably connected to the detection magnetic ring 14 on the piston rod 15 .

[0026] Example 3 Based on the counterweight cylinder with displacement detection described in the first and second embodiments, this embodiment provides a hydraulic system, which is equipped with the counterweight cylinder 23 with displacement detection described in the first or second embodiment.

[0027] Inlet P of the proportional solenoid valve 25 is connected to the power source, while the oil return port T is connected to the oil tank. Outlet A of the proportional solenoid valve 25 is connected to inlet A of the balancing valve 24, while outlet B of the proportional solenoid valve 25 is connected to inlet B of the balancing valve 24. Outlet D of the balancing valve 24 is connected to the small chamber of the counterweight cylinder 23, while outlet C of the balancing valve 24 is connected to the large chamber of the counterweight cylinder 23. After the counterweight is attached, the balancing valve 24 locks the hydraulic oil in the small chamber of the counterweight cylinder 23 to prevent it from falling.

[0028] To control the lifting of the counterweight cylinder 23, oil enters inlet P of the proportional solenoid valve 25. The hydraulic power source comes from the gear pump connected to the engine's power take-off port. When the proportional solenoid valve 25 is shifted to the left position, oil flows through outlet A of the proportional solenoid valve 25 and into the small chamber of the counterweight cylinder 23 through the balancing valve 24. The oil in the large chamber of the counterweight cylinder 23 then flows back to the tank through the oil return port T of the proportional solenoid valve 23. During the lifting process of the counterweight cylinder 23, the displacement sensor 22 transmits the displacement of the counterweight cylinder 23 to the controller 21. When the counterweight is approaching its highest position, the controller 21 reduces the current value of the left position of the proportional solenoid valve 25. This reduces the flow rate of the hydraulic system, slowing the movement of the counterweight cylinder 23 and alleviating the impact vibration generated when the upper surface 32 of the counterweight contacts the lower surface 33 of the turntable.

[0029] As counterweight cylinder 23 descends, oil enters inlet P of proportional solenoid valve 25. The hydraulic power source comes from a gear pump connected to the engine's power take-off port. Proportional solenoid valve 25 shifts to the right position, and oil enters the large chamber of counterweight cylinder 23 through outlet 2B of proportional solenoid valve 25. Oil in the small chamber of counterweight cylinder 23 then flows through balancing valve 24 to the oil return port T of proportional solenoid valve 25 and back to the fuel tank. As counterweight cylinder 23 descends, displacement sensor 22 transmits the displacement of counterweight cylinder 23 to controller 21. As the counterweight approaches its lowest position, controller 21 reduces the current flowing to the right of proportional solenoid valve 25. This reduces the flow rate in the hydraulic system, slowing the movement of counterweight cylinder 23 and mitigating the impact vibrations caused by contact between the counterweight and the vehicle frame.

[0030] If the counterweight cylinder 23 leaks or other factors cause the counterweight piston rod to extend, the counterweight will drop accordingly. The displacement sensor 23 transmits the detected counterweight displacement to the controller 21. If the downward displacement exceeds the set value, the controller 21 issues an alarm and prompts the operator to raise the counterweight to the set position again to avoid safety accidents.

[0031] The present invention uses a displacement sensor to monitor the counterweight's position in real time. When the counterweight approaches its highest or lowest position, a controller reduces the input current to the proportional solenoid valve, thereby lowering the hydraulic system flow rate, slowing the counterweight cylinder's movement speed and reducing vehicle impact vibration. When the counterweight is attached for a long time, the counterweight cylinder's piston rod extends. The displacement sensor detects the amount of downward movement of the counterweight. If the downward movement exceeds a set value, the controller issues an alarm to the operator, preventing safety accidents.

[0032] Example 4 Based on the counterweight cylinder with displacement detection described in Example 1 and Example 2, and the hydraulic system described in Example 3, this embodiment provides a crane, which is equipped with the counterweight cylinder with displacement detection described in Example 1 or Example 2, or is equipped with the hydraulic system described in Example 3.

[0033] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A counterweight cylinder with displacement detection, characterized in that: include: Piston rod (15); a piston (17) mounted on one end of the piston rod (15), wherein the piston (17) is slidably connected to the cylinder body; A detection rod (13) that remains relatively stationary with the cylinder body; A detection magnetic ring (14) that moves synchronously with the piston rod (15); The detection magnetic ring (14) is sleeved on the detection rod (13) and is slidably connected to the detection rod (13), forming a displacement sensor (22) for detecting the relative position relationship between the piston rod (15) and the cylinder body.

2. The counterweight cylinder with displacement detection according to claim 1, characterized in that: The cylinder body comprises a cylinder barrel (18) and a cylinder bottom (16) arranged at one end of the cylinder barrel (18).

3. The counterweight cylinder with displacement detection according to claim 2, characterized in that: One end of the detection rod (13) is mounted on the cover plate (12), and the other end passes through the cylinder bottom (16) and is inserted into the reserved hole on the piston rod (15). The cover plate (12) is mounted on the cylinder bottom (16). The detection magnetic ring (14) is sleeved on the detection rod (13) and embedded in the reserved hole on the piston rod (15).

4. The counterweight cylinder with displacement detection according to claim 2, characterized in that: One end of the detection rod (13) is mounted on the outer wall of the cylinder (18); one end of the piston rod (15) located outside the cylinder (18) is provided with a flange (19); the other end of the detection rod (13) is slidably connected to the detection magnetic ring (14) on the piston rod (15).

5. A hydraulic system, characterized in that: The hydraulic system is equipped with a counterweight cylinder (23) with displacement detection according to any one of claims 1 to 4.

6. The hydraulic system according to claim 5, characterized in that The large chamber of the counterweight oil cylinder (23) is connected to the outlet 1 of the balance valve (24), the small chamber of the counterweight oil cylinder (23) is connected to the outlet 2 of the balance valve (24), the inlet 1 of the balance valve (24) is connected to the outlet 1 of the proportional solenoid valve (25), the inlet 2 of the balance valve (24) is connected to the outlet 2 of the proportional solenoid valve (25), the inlet of the proportional solenoid valve (25) is connected to the oil source, and the oil return port of the proportional solenoid valve (25) is connected to the oil tank; the controller (21) is electrically connected to the displacement sensor (22) of the counterweight oil cylinder (23) and the control end of the proportional solenoid valve (25), respectively.

7. The hydraulic system according to claim 6, characterized in that When the counterweight oil cylinder (23) is controlled to be lifted, the proportional solenoid valve (25) is switched to the left position, and the hydraulic oil enters the small chamber of the counterweight oil cylinder (23) through the inlet of the proportional solenoid valve (25), the outlet 1 of the proportional solenoid valve (25), the inlet 1 of the balancing valve (24), and the outlet 2 of the balancing valve (24); the hydraulic oil in the large chamber of the counterweight oil cylinder (23) flows into the oil tank through the outlet 1 of the balancing valve (24), the inlet 2 of the balancing valve (24), the outlet 2 of the proportional solenoid valve (25), and the oil return port of the proportional solenoid valve (25); the controller (21) collects the displacement of the piston rod through the displacement sensor (22) and adjusts the current value of the control end of the proportional solenoid valve (25) according to the set control logic, so as to reduce the impact vibration generated by the upper surface of the counterweight block and the lower surface of the turntable when the counterweight oil cylinder (23) is lifted to the limit position.

8. The hydraulic system according to claim 6, characterized in that When the counterweight oil cylinder (23) is controlled to fall, the proportional solenoid valve (25) is switched to the right position, and the hydraulic oil enters the large chamber of the counterweight oil cylinder (23) through the inlet of the proportional solenoid valve (25), the second outlet of the proportional solenoid valve (25), the second inlet of the balancing valve (24), and the first outlet of the balancing valve (24); the hydraulic oil in the small chamber of the counterweight oil cylinder (23) flows into the oil tank through the second outlet of the balancing valve (24), the first inlet of the balancing valve (24), the first outlet of the proportional solenoid valve (25), and the oil return port of the proportional solenoid valve (25); the controller (21) collects the displacement of the piston rod through the displacement sensor (22) and adjusts the current value of the control end of the proportional solenoid valve (25) according to the set control logic, so as to reduce the impact vibration generated by the counterweight block and the frame when the counterweight oil cylinder (23) falls to the extreme position.

9. The hydraulic system according to claim 6, characterized in that When the counterweight cylinder (23) extends abnormally, causing the counterweight to fall, the displacement sensor (22) transmits the collected piston rod displacement to the controller (21). When the displacement exceeds the set value, the controller (21) issues an alarm and prompts the operator to lift the counterweight to the set position again.

10. A crane, characterized in that: The crane is equipped with the hydraulic system according to any one of claims 5 to 9.

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