A hydraulic cylinder and a hydraulic device containing the same

Abstract

A hydraulic cylinder and hydraulic equipment containing the hydraulic cylinder relate to the field of hydraulic technology, including a cylinder body, a valve core, a piston assembly, a power device and an oil inlet. The cylinder body includes a cylinder cover and a cylinder barrel, one end of the valve core is conical, and the piston assembly includes a piston, a piston rod and an oil channel. The side of the cylinder body from the piston to the cylinder cover is a rodless chamber, and the other side of the piston is a rod chamber. The rodless chamber is connected to the oil inlet. In this structure, the piston assembly can be moved by controlling the axial movement of the valve core to open and close the oil channel, and digital precision control can be achieved in coordination with a numerical control system. The structure is simple, the service life is long, and it is energy-saving and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic technology, and in particular to a hydraulic cylinder and hydraulic equipment containing the hydraulic cylinder. Background Art

[0002] For example, hydraulic equipment such as hydraulic forging machines, hydraulic bending machines, hydraulic shearing machines, hydraulic injection molding machines and hydraulic climbing molds require multiple hydraulic cylinders to work synchronously, which involves the synchronization problem of multiple hydraulic cylinders. For example, hydraulic equipment such as vibration test benches, hydraulic robots and hydraulic CNC machine tools are mostly high-precision machinery, which involves the accuracy of hydraulic cylinders. Regardless of whether it is the synchronization problem of multiple hydraulic cylinders or the accuracy problem of hydraulic cylinders, there are high requirements for the stability, accuracy and rapid response capability of the hydraulic cylinders. Although the existing servo hydraulic cylinders can meet the above requirements, their complex structure, extremely high requirements for oil cleanliness, high energy consumption and other disadvantages limit their application scope.

[0003] Patent application number: 201611000955.2 discloses a digital servo hydraulic cylinder, which controls the valve core by controlling the motor and the ball screw, has high frequency response, high starting frequency, and low unit power cost, but the solution has the following disadvantages:

[0004] 1. One end of the servo direction control valve core described in the scheme is connected to one end of the limit block, the other end of the limit block is connected to one end of the axial clearance compensator, and the other end of the axial clearance compensator is connected to the shaft of the control motor. There are many transmission chains, and it is not easy to ensure accuracy;

[0005] 2. The servo direction control valve core rotates with the motor and has a short life;

[0006] 3. The variable area of ​​the rodless piston is twice the surface area of ​​the rod piston, resulting in high energy consumption;

[0007] 4. The solution does not disclose how the lead screw nut engages with the center hole of the piston rod.

[0008] The above scheme has the disadvantages of complex structure, short life, high energy consumption and poor energy conservation and environmental protection. Summary of the invention

[0009] Technical solution 1 of the present invention proposes a hydraulic cylinder, which can realize digital precision control in coordination with a numerical control system, has a simple structure, a long service life, and is energy-saving and environmentally friendly.

[0010] A hydraulic cylinder comprises a cylinder body, a valve core, a piston assembly, a power device and an oil inlet, wherein the cylinder body comprises a cylinder cover and a cylinder barrel, the cylinder cover has a hole in the center, a valve core is arranged in the hole, a sealing member is arranged between the valve core and the hole, one end of the valve core is conical, the cylinder cover is mounted at one end of the cylinder barrel, a piston assembly is mounted in the cylinder barrel, the piston assembly comprises a piston, a piston rod and an oil passage, the side from the piston to the cylinder cover in the cylinder body is a rodless cavity, the other side of the piston is a rod cavity, the power device is connected to the valve core, and the rodless cavity is communicated with the oil inlet.

[0011] Preferably, the present invention further comprises a valve seat, which is mounted on the end face of the piston assembly, has a hole in the center of the valve seat, one end of the oil passage is connected to the rodless chamber through the hole on the valve seat, and the other end is connected to the oil return circuit.

[0012] Preferably, the present invention may further include an oil outlet and a third oil port, the cylinder body further includes an oil return cylinder and a cylinder cover 2, the oil return cylinder has a spacer edge at one end, a cylinder cover 1 is installed at one end of the cylinder barrel, and the other end is installed with the spacer edge, the other end of the oil return cylinder is installed with a box cover 2, there is a hole in the center of the spacer edge, a seal is provided in the hole, the seal cooperates with the piston rod of the piston assembly, the third oil port is located on the cylinder barrel near the spacer edge, the oil inlet is communicated with the rodless chamber, the oil return port is on the oil return cylinder, and the third oil port is connected to the energy accumulator.

[0013] Preferably, the present invention may also include an oil outlet and a third oil port, the cylinder body also includes a cylinder head 2, the cylinder head 2 is installed on the end of the cylinder barrel away from the cylinder head 1, the cylinder head 2 has a hole in the center, a seal is provided in the hole, the seal cooperates with the piston rod of the piston assembly, the third oil port is located on the cylinder barrel near the cylinder head 2, the oil inlet is communicated with the rodless chamber, and the oil return port is arranged on the piston rod and communicated with the oil channel.

[0014] Preferably, the present invention may further include a spring and an oil return port, wherein the spring is in the rod cavity, the cylinder barrel has an oil return port, the oil return port is communicated with the rod cavity, the cylinder body further includes a cylinder cover 2, and the cylinder cover 2 is installed at one end of the cylinder barrel away from the cylinder cover 1.

[0015] Preferably, the valve core comprises a valve core rod and a valve core head, one end of the valve core head is conical, and the other end is floatingly connected to one end of the valve core rod.

[0016] Preferably, the power device includes a fixed seat, a motor, a rack and a roller. The fixed seat is connected to the cylinder body, the motor is installed on the fixed seat, a gear is installed at the output end of the motor, the gear is meshed with the rack, the roller is pressed on the non-meshing side of the rack, the roller is connected to the fixed seat, the rack is connected to the valve core, and the motor is preferably a servo motor.

[0017] Preferably, the oil inlet is connected to the energy accumulator through a one-way valve.

[0018] Technical solution 2 of the present invention also proposes a hydraulic device containing a hydraulic cylinder, wherein the hydraulic cylinder is any hydraulic cylinder described in technical solution 1, and has stable performance, high precision, fast response speed, and is energy-saving and environmentally friendly.

[0019] Compared with the prior art, the beneficial effects of the present invention are: in this structure, the hydraulic pressure in the rodless chamber makes the piston assembly have the potential energy to move away from the valve core, and the pressure in the rod chamber makes the piston assembly have the potential energy to move toward the valve core. When the piston assembly is stationary or moving toward the valve core, the oil inlet and the oil return port are connected. When the piston assembly is running at low load, the valve core and the valve seat will maintain an appropriate gap to control the oil inlet amount of the oil channel. By controlling the axial movement of the valve core to open and close the oil channel, the piston assembly can be followed, and the coordinated CNC system can achieve digital precision control. The structure is simple, the service life is long, and it is energy-saving and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of the present invention (I).

[0021] Figure 2 This is a structural schematic diagram of the present invention (II).

[0022] Figure 3 This is a structural schematic diagram of the present invention (III).

[0023] Figure 4 This is a structural schematic diagram of the present invention (IV).

[0024] Figure 5 This is a structural schematic diagram of the present invention (V).

[0025] In the figure:

[0026] 1 cylinder body, 101 cylinder head one, 102 cylinder barrel, 103 cylinder head two, 104 oil return cylinder, 105 interval edge, 2 valve core, 201 valve core rod, 202 valve core head, 3 piston assembly, 301 piston, 302 piston rod, 303 oil channel, 4 valve seat, 5 power unit, 501 fixed seat, 502 motor, 503 rack, 6 spring, 7 oil inlet, 8 oil return port, 9 third oil port. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] Embodiment 1

[0029] A hydraulic cylinder, such as Figure 1As shown, it includes a cylinder body 1, a valve core 2, a piston assembly 3, a valve seat 4, a power device 5 and an oil inlet 7. The cylinder body 1 includes a cylinder head 101 and a cylinder barrel 102. The cylinder head 101 has a hole in the center, a valve core 2 is arranged in the hole, a seal is arranged between the valve core 2 and the hole, one end of the valve core 2 is conical, the cylinder head 101 is installed at one end of the cylinder barrel 102, a piston assembly 3 is installed in the cylinder barrel 102, the piston assembly 3 includes a piston 301, a piston rod 302 and an oil passage 303, and the piston 301 in the cylinder body 1 is provided with a seal. One side of the cylinder head 101 is a rodless chamber, and the other side of the piston 301 is a rod chamber. The valve seat 4 is installed on the end face of the piston assembly 3. There is a hole in the center of the valve seat 4. One end of the oil channel 303 is connected to the rodless chamber through the hole on the valve seat 4, and the other end is connected to the return oil circuit. The rodless chamber is connected to the oil inlet 7. The axial movement of the valve core 2 can open and close the oil channel 303. The power device 5 is connected to the valve core 2. There is a pressure (spring force or liquid pressure) in the rod chamber that causes the piston assembly 3 to move toward the cylinder head 101.

[0030] The working principle of this embodiment is as follows: the power device 5 receives a digital signal to drive the valve core 2 to move axially. When the valve core 2 moves toward the piston assembly 3 and the valve core 2 and the valve seat 4 are closed, the oil passage is closed. At this time, the hydraulic oil delivered from the oil inlet 7 causes the piston assembly 3 to move away from the valve core 2. When the movement speed of the piston assembly 3 is faster than that of the valve core 2, there is a gap between the valve core 2 and the valve seat 4, and the hydraulic oil flows out from the oil passage 303. The pressure from the rod chamber gives the piston assembly 3 potential energy to move toward the valve core 2, and the piston assembly 3 follows the axial movement of the valve core 2 and moves in the pressure balance position between the rod chamber and the rodless chamber.

[0031] Embodiment 2

[0032] like Figure 2 As shown, on the basis of embodiment 1, it also includes a return oil port 8 and a third oil port 9. The cylinder body 1 also includes a cylinder head 2 103 and an oil return cylinder 104. One end of the oil return cylinder 104 has a spacing edge 105. One end of the cylinder barrel 102 is installed with a cylinder head 101, and the other end is installed with the spacing edge 105. The other end of the oil return cylinder 104 is installed with a box cover 2 103. The spacing edge 105 has a hole in the center, and a seal is provided in the hole. The seal cooperates with the piston rod 302 of the piston assembly 3. The third oil port 9 is located on the cylinder barrel 102 near the spacing edge 105, the oil inlet 7 is connected to the rodless cavity, the oil return port 8 is on the oil return cylinder 104, and the third oil port 9 is connected to the energy accumulator.

[0033] The working principle of this embodiment is as follows: when the valve core 2 moves toward the piston 301, the valve seat 4 is closed, and the hydraulic oil pushes the piston assembly 3 to move in the direction away from the valve core 2. The hydraulic oil in the rod chamber is pressed into the accumulator through the third oil port 9, and at the same time, the potential energy for the piston assembly 3 to move in the direction of the valve core 2 is given. When the valve core 2 moves in the direction away from the piston assembly 3, the hydraulic oil in the rod chamber flows into the oil return port 8. The potential energy of the piston assembly 3 moving in the direction of the valve core 2 is greater than the potential energy of moving in the direction away from the valve core 2, so that the piston assembly 3 follows the axial movement of the valve core 2.

[0034] Embodiment 3

[0035] like Figure 3 As shown, on the basis of embodiment 1, it also includes an oil return port 8 and a third oil port 9, the cylinder body 1 also includes a cylinder head 103, the cylinder head 103 is installed at the end of the cylinder barrel 102 away from the cylinder head 101, the cylinder head 103 has a hole in the center, a seal is arranged in the hole, the seal cooperates with the piston rod 302 of the piston assembly 3, the third oil port 9 is located on the cylinder barrel 102 near the cylinder head 103, the third oil port 9 is connected to the energy accumulator, the oil inlet 7 is communicated with the rodless cavity, the oil return port 8 is arranged on the piston rod 302, and is communicated with the oil passage 303, and the working principle of this embodiment is the same as that of embodiment 2.

[0036] Embodiment 4

[0037] like Figure 4 As shown, on the basis of embodiment 1, it also includes a spring 6 and an oil return port 8, the spring 6 is in the rod cavity, the cylinder body 1 also includes a cylinder cover 103, the cylinder cover 103 is installed at one end of the cylinder barrel 102 away from the cylinder cover 1 101, the cylinder barrel 102 has an oil return port 8, and the oil return port 8 is communicated with the rod cavity.

[0038] Embodiment 5

[0039] like Figure 5 As shown, the valve core 2 described in the present invention includes a valve core rod 201 and a valve core head 202. One end of the valve core head 202 is conical, and the other end is connected to one end of the valve core rod 201. The valve core rod 201 and the valve core head 202 of the valve core 2 can be floatingly connected to prevent the position of the valve core 2 or the valve seat 4 from shifting, and at the same time facilitate the replacement of the valve core head 202.

[0040] Embodiment 6

[0041] like Figure 3 and Figure 4 As shown, the oil inlet 7 described in the present invention is connected to the energy accumulator through a one-way valve to compensate for the pressure loss of the energy accumulator.

[0042] Embodiment 7

[0043] like Figure 2As shown, the power device 5 described in the present invention includes a fixed seat 501, a motor 502, a rack 503 and a roller. The fixed seat 501 is connected to the cylinder body 1, and the motor 502 is installed on the fixed seat 501. A gear is installed at the output end of the motor 502, and the gear is meshed with the rack 503. The roller is pressed on the non-meshing side of the rack 503, the roller is connected to the fixed seat 501, and the rack 503 is connected to the valve core 2. The motor 502 is preferably a servo motor. The working principle of this embodiment is: the motor 502 receives a digital signal to drive the gear to rotate, the gear is meshed with the rack 503 to make the rack 503 move axially, and the roller plays a guiding role.

[0044] To sum up, the above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hydraulic cylinder, comprising a cylinder body (1), a valve core (2), a piston assembly (3), a power device (5), an oil inlet (7), a valve seat (4), an oil return port (8) and a third oil port (9), characterized in that: The cylinder body (1) comprises a cylinder head (101) and a cylinder barrel (102). The cylinder head (101) has a hole at its center. A valve core (2) is disposed in the hole. A sealing member is disposed between the valve core (2) and the hole. One end of the valve core (2) is conical. The cylinder head (101) is mounted on one end of the cylinder barrel (102). A piston assembly (3) is mounted in the cylinder barrel (102). The piston assembly (3) comprises a piston (301), a piston rod (302) and an oil passage (303). The side from the piston (301) to the cylinder head (101) in the cylinder body (1) is a rodless chamber, and the other side of the piston (301) is a rod chamber. The power device (5) is connected to the valve core (2), and the rodless chamber is communicated with the oil inlet (7). The valve seat (4) is installed on the end surface of the piston assembly (3), and the center of the valve seat (4) has a hole. One end of the oil channel (303) is communicated with the rodless chamber through the hole on the valve seat (4), and the other end is communicated with the return oil circuit. The cylinder body (1) also includes a cylinder head (103) and an oil return cylinder (104). One end of the oil return cylinder (104) has a spacing edge (105). A cylinder head 1 (101) is installed at one end of the cylinder barrel (102), and the other end is installed with a spacing edge (105). A cylinder head 2 (103) is installed at the other end of the return oil barrel (104). A hole is provided at the center of the spacing edge (105), and a seal is provided in the hole. The seal cooperates with the piston rod (302) of the piston assembly (3). The third oil port (9) is located on the cylinder barrel (102) near the spacing edge (105). The oil inlet (7) is communicated with the rodless cavity. The return oil port (8) is on the return oil barrel (104). The third oil port (9) is connected with an energy accumulator. The oil inlet (7) is communicated with the energy accumulator through a one-way valve. The valve core (2) includes a valve core rod (201) and a valve core head (202). One end of the valve core head (202) is conical, and the other end is floatingly connected to one end of the valve core rod (201).

2. A hydraulic cylinder according to claim 1, characterized in that: The power device (5) comprises a fixed seat (501), a motor (502), a rack (503) and a roller. The fixed seat (501) is connected to the cylinder body (1). The motor (502) is mounted on the fixed seat (501). A gear is mounted on the output end of the motor (502). The gear is meshed with the rack (503). The roller is pressed on a non-meshing side of the rack (503). The roller is connected to the fixed seat (501). The rack (503) is connected to the valve core (2).

3. A hydraulic device comprising a hydraulic cylinder, characterized in that: The hydraulic cylinder is any one of the hydraulic cylinders described in claims 1 to 2.

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