Pressure protection oil way of hydraulic device

Abstract

The invention provides a pressure protection oil way of a hydraulic device, relates to the technical field of oil ways, and aims to solve the technical problem that an oil cylinder of the hydraulic device in the prior art is damaged due to expansion when an electromagnetic valve is damaged. A pressure protection oil way of a hydraulic device comprises an oil cylinder, an upper oil tank, a working oil way and a first control oil way, the oil cylinder is connected with the upper oil tank and the working oil way, and the first control oil way comprises a first cartridge valve, a first oil tank, a first electromagnetic valve, a first overflow valve, a first pipeline, a second pipeline and a third pipeline. One end of the second pipeline is connected with a first pressure cavity of the first cartridge valve, the other end of the second pipeline is connected with the second pipeline through a third pipeline, and the first overflow valve is connected with the second pipeline through a third pipeline; the first overflow valve is connected with the first oil tank.

Description

Technical Field

[0001] The invention relates to the technical field of oil circuits, in particular to a pressure protection oil circuit for a hydraulic device. Background Art

[0002] Hydraulic devices are mainly used in press forming. Taking wheel hub processing as an example, the raw materials are placed on the lower die, and the upper die presses the raw materials downward, and the raw materials are pressed into the shape of the wheel hub according to the shapes of the upper and lower dies. The pressure of the hydraulic device comes from the oil cylinder. The working oil circuit of the oil cylinder is connected to a cartridge valve, and the pressure chamber of the cartridge valve is connected to a solenoid valve. The cartridge valve is also connected to a direct-acting relief valve. Under normal working conditions, when the oil in the oil cylinder flows back through the working oil circuit, the solenoid valve switches so that the oil in the pressure chamber flows back to the oil tank of the solenoid valve through the solenoid valve. At this time, the valve core in the cartridge valve retreats, and the oil in the oil cylinder flows back to the return oil tank through the working oil circuit and the cartridge valve. However, when the solenoid valve fails, the oil in the pressure chamber cannot flow back to the oil tank of the solenoid valve, so the valve core of the cartridge valve cannot retreat, and the oil in the oil cylinder cannot flow back to the return oil tank through the cartridge valve, and can only be discharged by the direct-acting relief valve. However, the flow and pressure of the hydraulic device used for wheel hub processing are often very large. Relying solely on the direct-acting relief valve to discharge oil will result in untimely oil return and expansion of the cylinder, causing damage. Summary of the invention

[0003] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a pressure protection oil circuit for a hydraulic device to solve the technical problem in the prior art that when the solenoid valve of the hydraulic device is damaged, the oil cylinder will swell and be damaged.

[0004] To solve the above technical problems, the present invention provides a pressure protection oil circuit of a hydraulic device, comprising an oil cylinder, an upper oil tank, a working oil circuit and a first control oil circuit, wherein the upper end of the oil cylinder is connected to the upper oil tank, and the lower part of the oil cylinder is connected to the working oil circuit, the first control oil circuit comprises a first cartridge valve, a first oil tank, a first solenoid valve, a first overflow valve, a first pipeline, a second pipeline and a third pipeline, one end of the first pipeline is connected to the working oil circuit, the other end of the first pipeline is connected to the first interface of the first cartridge valve, the second interface of the first cartridge valve is connected to the first oil tank, a first valve core for controlling the on and off of the first interface and the second interface is movably connected in the first cartridge valve, one end of the second pipeline is connected to the first pressure chamber of the first cartridge valve, the oil in the first pressure chamber drives the first valve core to disconnect the first interface and the second interface, the other end of the second pipeline is connected to the first solenoid valve, the first solenoid valve is connected to the first oil tank, the first overflow valve is connected to the middle part of the second pipeline through the third pipeline, and the first overflow valve is connected to the first oil tank.

[0005] After adopting the above structure, a pressure protection oil circuit of a hydraulic device of the present invention has the following advantages: during normal operation, the first solenoid valve connects the first pressure chamber with the first oil tank, the oil in the first pressure chamber flows into the first oil tank, the first valve core retreats, the first interface and the second interface are connected, and the oil in the oil cylinder flows into the first oil tank through the working oil circuit, the first pipeline and the first cartridge valve; when the first solenoid valve fails, the first overflow valve can connect the first pressure chamber with the first oil tank, the oil in the first pressure chamber can flow into the first oil tank, and the first interface and the second interface can also be connected, so that the oil in the oil cylinder can flow back to the first oil tank normally, thereby preventing the oil in the oil cylinder from swelling and being damaged due to untimely reflux. Moreover, compared with the overflow valve in the prior art, since the first overflow valve does not need to drain the oil from the oil cylinder, a smaller overflow valve can be selected, thereby reducing the cost.

[0006] As an improvement, the first valve core is movably connected in the first cartridge valve along the left-right direction, the first interface and the second interface are both arranged on the right part of the first cartridge valve, and the first pressure chamber is arranged on the left side of the first valve core. The oil in the first pressure chamber drives the first valve core to move to the right so that the first interface and the second interface are disconnected.

[0007] As an improvement, the first control oil circuit also includes a fourth pipeline, one end of the fourth pipeline is connected to the first solenoid valve, and the other end of the fourth pipeline is connected to the middle part of the first pipeline. When the first solenoid valve is switched to the left position, the second pipeline is unidirectionally connected to the first oil tank via the first solenoid valve. When the first solenoid valve is switched to the right position, the fourth pipeline is unidirectionally connected to the second pipeline via the first solenoid valve.

[0008] As an improvement, the working oil circuit is also connected to a second control oil circuit, which includes a second cartridge valve, a second oil tank, a second solenoid valve, a second overflow valve, a fifth pipeline, a sixth pipeline and a seventh pipeline. One end of the fifth pipeline is connected to the working oil circuit, and the other end of the fifth pipeline is connected to the third interface of the second cartridge valve. The fourth interface of the second cartridge valve is connected to the second oil tank. A second valve core for controlling the on and off of the third interface and the fourth interface is movably connected in the second cartridge valve. One end of the sixth pipeline is connected to the second pressure chamber of the second cartridge valve. The oil in the second pressure chamber drives the second valve core to disconnect the third interface and the fourth interface. The other end of the sixth pipeline is connected to the second solenoid valve, the second solenoid valve is connected to the second oil tank, the second overflow valve is connected to the middle of the sixth pipeline through the seventh pipeline, the second overflow valve is connected to the second oil tank, and the second cartridge valve has a smaller caliber than the first cartridge valve. With this structure, the first control oil circuit is for the case where the cylinder piston rod moves quickly, while the second control oil circuit is for the case where the cylinder piston rod moves slowly. Therefore, the caliber of the second cartridge valve is smaller than the first cartridge valve. Similarly, the second overflow valve and other structures are also arranged in the second control oil circuit as pressure protection elements to prevent the oil in the cylinder from swelling and damage due to untimely reflux.

[0009] As an improvement, the second valve core is movably connected in the second cartridge valve along the left-right direction, the third interface and the fourth interface are both arranged on the right part of the second cartridge valve, and the second pressure chamber is arranged on the left side of the second valve core. The oil in the second pressure chamber drives the second valve core to move to the right so that the third interface and the fourth interface are disconnected.

[0010] As an improvement, the second control oil circuit also includes an eighth pipeline, one end of the eighth pipeline is connected to the second solenoid valve, and the other end of the eighth pipeline is connected to the middle of the fifth pipeline. When the second solenoid valve is switched to the left position, the sixth pipeline is unidirectionally connected to the second oil tank via the second solenoid valve. When the second solenoid valve is switched to the right position, the eighth pipeline is unidirectionally connected to the sixth pipeline via the second solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the present invention.

[0012] Figure 2 It is a structural schematic diagram of the first control oil circuit in the present invention.

[0013] Figure 3 It is a structural schematic diagram of the second control oil circuit in the present invention.

[0014] 1. Cylinder; 2. Upper oil tank; 3. Working oil circuit; 4. First control oil circuit; 41. First cartridge valve; 42. First oil tank; 43. First solenoid valve; 45. First overflow valve; 47. First pipeline; 48. Second pipeline; 49. Third pipeline; 410. Fourth pipeline; 5. First interface; 6. Second interface; 7. First valve core; 8. First pressure chamber; 9. Second control oil circuit; 91. Second cartridge valve; 92. Second oil tank; 93. Second solenoid valve; 95. Second overflow valve; 97. Fifth pipeline; 98. Sixth pipeline; 99. Seventh pipeline; 910. Eighth pipeline; 10. Third interface; 11. Fourth interface; 12. Second valve core; 13. Second pressure chamber. DETAILED DESCRIPTION

[0015] A pressure protection oil circuit of a hydraulic device according to the present invention is described in detail below with reference to the accompanying drawings.

[0016] like Figures 1 to 3As shown, a pressure protection oil circuit of a hydraulic device includes an oil cylinder 1, an upper oil tank 2, a working oil circuit 3 and a first control oil circuit 4. The upper end of the oil cylinder 1 is connected to the upper oil tank 2, and the lower part of the oil cylinder 1 is connected to the working oil circuit 3. The first control oil circuit 4 includes a first cartridge valve 41, a first oil tank 42, a first solenoid valve 43, a first overflow valve 45, a first pipeline 47, a second pipeline 48 and a third pipeline 49. One end of the first pipeline 47 is connected to the working oil circuit 3, and the other end of the first pipeline 47 is connected to the first interface 5 of the first cartridge valve 41. The second interface 6 of the first cartridge valve 41 is connected to the first oil tank 42. The first cartridge valve 41 is connected to the working oil circuit 3. A first valve core 7 for controlling the on / off of the first interface 5 and the second interface 6 is movably connected to the first cartridge valve 41 in the left-right direction. The first interface 5 and the second interface 6 are both arranged at the right part of the first cartridge valve 41. One end of the second pipeline 48 is connected to the first pressure chamber 8 of the first cartridge valve 41. The first pressure chamber 8 is arranged at the left side of the first valve core 7. The oil in the first pressure chamber 8 drives the first valve core 7 to disconnect the first interface 5 and the second interface 6. Specifically, the oil in the first pressure chamber 8 drives the first valve core 7 to move rightward to disconnect the first interface 5 and the second interface 6. That is, Figure 1 and Figure 2 In the state shown, when the oil in the first pressure chamber 8 is discharged, the first valve core 7 moves to the left so that the first interface 5 is connected to the second interface 6; the other end of the second pipeline 48 is connected to the first solenoid valve 43, the first solenoid valve 43 is connected to the first oil tank 42, the first overflow valve 45 is connected to the middle part of the second pipeline 48 through the third pipeline 49, and the first overflow valve 45 is connected to the first oil tank 42.

[0017] like Figure 1 and Figure 2 As shown, the first control oil circuit 4 also includes a fourth pipeline 410, one end of the fourth pipeline 410 is connected to the first solenoid valve 43, and the other end of the fourth pipeline 410 is connected to the middle part of the first pipeline 47. When the first solenoid valve 43 is switched to the left position, the second pipeline 48 is unidirectionally connected to the first oil tank 42 via the first solenoid valve 43, that is, the oil in the second pipeline 48 flows into the first oil tank 42 via the A and T ports of the first solenoid valve 43. When the first solenoid valve 43 is switched to the right position, the fourth pipeline 410 is unidirectionally connected to the second pipeline 48 via the first solenoid valve 43.

[0018] like Figure 1 and Figure 3As shown, the working oil circuit 3 is also connected to the second control oil circuit 9, and the second control oil circuit 9 includes a second cartridge valve 91, a second oil tank 92, a second solenoid valve 93, a second overflow valve 95, a fifth pipeline 97, a sixth pipeline 98 and a seventh pipeline 99. One end of the fifth pipeline 97 is connected to the working oil circuit 3, and the other end of the fifth pipeline 97 is connected to the third interface 10 of the second cartridge valve 91. The fourth interface 11 of the second cartridge valve 91 is connected to the second oil tank 92. A second valve core 12 for controlling the on-off of the third interface 10 and the fourth interface 11 is movably connected in the second cartridge valve 91. The second valve core 12 is movably connected in the second cartridge valve 91 along the left and right directions. The third interface 10 and the fourth interface 11 are both arranged on the right part of the second cartridge valve 91. One end of the sixth pipeline 98 is connected to the second cartridge valve 91. The second pressure chamber 13 of the valve 91 is arranged on the left side of the second valve core 12, and the oil in the second pressure chamber 13 drives the second valve core 12 to disconnect the third interface 10 and the fourth interface 11. Specifically, the oil in the second pressure chamber 13 drives the second valve core 12 to move rightward to disconnect the third interface 10 and the fourth interface 11. The specific principle is the same as that of the first cartridge valve 41; the other end of the sixth pipeline 98 is connected to the second solenoid valve 93, and the second solenoid valve 93 is connected to the second oil tank 92. The second overflow valve 95 is connected to the middle part of the sixth pipeline 98 through the seventh pipeline 99, and the second overflow valve 95 is connected to the second oil tank 92. The second cartridge valve 91 has a smaller caliber than the first cartridge valve 41; it should be noted that the first oil tank 42 and the second oil tank 92 are actually the same oil tank.

[0019] like Figure 3 As shown, the second control oil circuit 9 also includes an eighth pipeline 910, one end of the eighth pipeline 910 is connected to the second solenoid valve 93, and the other end of the eighth pipeline 910 is connected to the middle of the fifth pipeline 97. When the second solenoid valve 93 is switched to the left position, the sixth pipeline 98 is unidirectionally connected to the second oil tank 92 via the second solenoid valve 93, that is, the oil in the sixth pipeline 98 flows into the second oil tank 92 via the A and T ports of the second solenoid valve 93. When the second solenoid valve 93 is switched to the right position, the eighth pipeline 910 is unidirectionally connected to the sixth pipeline 98 via the second solenoid valve 93.

[0020] During normal operation, the first solenoid valve 43 connects the first pressure chamber 8 with the first oil tank 42, the oil in the first pressure chamber 8 flows into the first oil tank 42, the first valve core 7 retreats, the first interface 5 is connected to the second interface 6, and the oil in the cylinder 1 flows into the first oil tank 42 through the working oil circuit 3, the first pipeline 47 and the first cartridge valve 41; when the first solenoid valve 43 fails, the first overflow valve 45 can connect the first pressure chamber 8 with the first oil tank 42, the oil in the first pressure chamber 8 can flow into the first oil tank 42, and the first interface 5 and the second interface 6 can also be connected, so that the oil in the cylinder 1 can flow back to the first oil tank 42 normally, preventing the oil in the cylinder 1 from swelling and being damaged due to the untimely reflux. Moreover, compared with the overflow valve in the prior art, the first overflow valve 45 does not need to drain the oil from the cylinder 1, so a smaller overflow valve can be selected, thereby reducing the cost.

[0021] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned one embodiment, and all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present invention.

Claims

1. A hydraulic device pressure protection oil circuit, characterized in that: The invention comprises an oil cylinder (1), an upper oil tank (2), a working oil circuit (3) and a first control oil circuit (4); the upper end of the oil cylinder (1) is connected to the upper oil tank (2); the lower part of the oil cylinder (1) is connected to the working oil circuit (3); the first control oil circuit (4) comprises a first cartridge valve (41), a first oil tank (42), a first solenoid valve (43), a first overflow valve (45), a first pipeline (47), a second pipeline (48) and a third pipeline (49); one end of the first pipeline (47) is connected to the working oil circuit (3); the other end of the first pipeline (47) is connected to a first interface (5) of the first cartridge valve (41); the second interface (6) of the first cartridge valve (41) is connected to the first oil tank (42); the A first valve core (7) for controlling the opening and closing of the first interface (5) and the second interface (6) is movably connected in the first cartridge valve (41); one end of the second pipeline (48) is connected to a first pressure chamber (8) of the first cartridge valve (41); the oil in the first pressure chamber (8) drives the first valve core (7) to disconnect the first interface (5) and the second interface (6); the other end of the second pipeline (48) is connected to the first solenoid valve (43); the first solenoid valve (43) is connected to the first oil tank (42); the first overflow valve (45) is connected to the middle of the second pipeline (48) through the third pipeline (49); and the first overflow valve (45) is connected to the first oil tank (42).

2. The hydraulic device pressure protection oil circuit according to claim 1, characterized in that: The first valve core (7) is movably connected in the first cartridge valve (41) along the left-right direction, the first interface (5) and the second interface (6) are both arranged on the right side of the first cartridge valve (41), the first pressure chamber (8) is arranged on the left side of the first valve core (7), and the oil in the first pressure chamber (8) drives the first valve core (7) to move rightward so that the first interface (5) and the second interface (6) are disconnected.

3. The hydraulic device pressure protection oil circuit according to claim 1, characterized in that: The first control oil circuit (4) further comprises a fourth pipeline (410), one end of the fourth pipeline (410) being connected to the first solenoid valve (43), and the other end of the fourth pipeline (410) being connected to the middle of the first pipeline (47); when the first solenoid valve (43) is switched to the left position, the second pipeline (48) is unidirectionally connected to the first oil tank (42) via the first solenoid valve (43); and when the first solenoid valve (43) is switched to the right position, the fourth pipeline (410) is unidirectionally connected to the second pipeline (48) via the first solenoid valve (43).

4. The hydraulic device pressure protection oil circuit according to claim 1, characterized in that: The working oil circuit (3) is further connected to a second control oil circuit (9), the second control oil circuit (9) comprising a second cartridge valve (91), a second oil tank (92), a second solenoid valve (93), a second overflow valve (95), a fifth pipeline (97), a sixth pipeline (98) and a seventh pipeline (99), one end of the fifth pipeline (97) being connected to the working oil circuit (3), the other end of the fifth pipeline (97) being connected to a third interface (10) of the second cartridge valve (91), a fourth interface (11) of the second cartridge valve (91) being connected to the second oil tank (92), and a passage for controlling the third interface (10) and the fourth interface (11) being movably connected in the second cartridge valve (91). The invention relates to a second valve core (12) disconnected from the second cartridge valve (91); one end of the sixth pipeline (98) is connected to the second pressure chamber (13) of the second cartridge valve (91); the oil in the second pressure chamber (13) drives the second valve core (12) to disconnect the third interface (10) and the fourth interface (11); the other end of the sixth pipeline (98) is connected to the second solenoid valve (93); the second solenoid valve (93) is connected to the second oil tank (92); the second overflow valve (95) is connected to the middle part of the sixth pipeline (98) through the seventh pipeline (99); the second overflow valve (95) is connected to the second oil tank (92); the second cartridge valve (91) has a smaller caliber than the first cartridge valve (41).

5. The hydraulic device pressure protection oil circuit according to claim 4, characterized in that: The second valve core (12) is movably connected in the second cartridge valve (91) along the left-right direction, the third interface (10) and the fourth interface (11) are both arranged on the right side of the second cartridge valve (91), and the second pressure chamber (13) is arranged on the left side of the second valve core (12). The oil in the second pressure chamber (13) drives the second valve core (12) to move rightward so that the third interface (10) and the fourth interface (11) are disconnected.

6. The hydraulic device pressure protection oil circuit according to claim 4, characterized in that: The second control oil circuit (9) further comprises an eighth pipeline (910), one end of the eighth pipeline (910) being connected to the second solenoid valve (93), and the other end of the eighth pipeline (910) being connected to the middle of the fifth pipeline (97); when the second solenoid valve (93) is switched to the left position, the sixth pipeline (98) is unidirectionally connected to the second oil tank (92) via the second solenoid valve (93); and when the second solenoid valve (93) is switched to the right position, the eighth pipeline (910) is unidirectionally connected to the sixth pipeline (98) via the second solenoid valve (93).

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