A digital hydraulic cylinder

Abstract

The present invention discloses a digital hydraulic cylinder, comprising a cylinder barrel and a cylinder seat, wherein a hollow piston rod is arranged in the cylinder barrel, one end of the piston rod is connected to a first bearing at the top end of a lead screw through a first piston, the other end of the piston rod is connected to a lead screw nut on the lead screw through a second piston, the lead screw is connected to a second bearing inside the cylinder seat outside the second piston, a first gear is arranged at the end of the lead screw, the first gear is meshed with a second gear at the top end of a transmission rod inside the cylinder seat, a third gear at the bottom end of the transmission rod is meshed with a fourth gear on a digital valve, the digital valve is connected to the cylinder seat, the cylinder barrel is provided with a first oil port and a second oil port, and both the first oil port and the second oil port are connected to the digital valve. The present invention adopts a digital hydraulic cylinder of the above structure, the rotation speed and number of turns of the lead screw can effectively transmit the speed and position of the piston rod, and then the output flow is adjusted by the digital valve to realize accurate control of the piston rod, which is more stable and reliable than a magnetostrictive sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of digital hydraulic cylinders, and in particular to a digital hydraulic cylinder. Background Art

[0002] Hydraulic is a widely used transmission technology in industry, especially in the field of linear motion. With its superior performance of heavy load, smoothness, impact resistance, durability and reliability, it is widely used in metal forming, rubber and plastic machinery, heavy machine tools, engineering machinery and other fields. In the prior art, in high-precision positioning devices, the commonly used positioning component is the hydraulic cylinder, which can not only provide positioning, but also provide a large positioning force.

[0003] The existing hydraulic cylinders on the market mainly rely on magnetostrictive sensors or gratings engraved on the piston rod to transmit position and speed signals. However, magnetostrictive sensors have poor anti-interference ability and high environmental requirements, while gratings on piston rods are difficult to process and seal. Summary of the invention

[0004] The purpose of the present invention is to provide a digital hydraulic cylinder, which solves the problems of poor anti-interference ability and high processing difficulty of the existing hydraulic cylinder.

[0005] To achieve the above-mentioned purpose, the present invention provides a digital hydraulic cylinder, including a cylinder barrel and a cylinder seat, a piston rod with a hollow interior is provided in the cylinder barrel, one end of the piston rod is connected to a first bearing at the top end of a lead screw through a first piston, and the other end of the piston rod is connected to a lead screw nut on the lead screw through a second piston, and the lead screw is connected to a second bearing inside the cylinder seat at the outside of the second piston, a first gear is provided at the end of the lead screw, the first gear is meshed with a second gear at the top end of a transmission rod inside the cylinder seat, a third gear at the bottom end of the transmission rod is meshed with a fourth gear on a digital valve, the digital valve is connected to the cylinder seat, and the cylinder barrel is provided with a first oil port and a second oil port, and the first oil port and the second oil port are both connected to the digital valve.

[0006] Preferably, the number of the second bearings is two, a bearing spacer is provided between the second bearings, the second bearing close to the first gear is connected to a locking sleeve, and the locking piece of the locking sleeve is connected to the cylinder seat.

[0007] Preferably, the second bearing close to the side of the lead screw nut is connected to a limit block, and the limit block is connected to the cylinder seat.

[0008] Preferably, the transmission rod is connected to the cylinder seat via a third bearing, the angle between the transmission rod and the lead screw is 90°, and the angle between the digital valve and the piston rod is 180°.

[0009] Preferably, the first gear and the second gear are located inside a first movable groove of the cylinder base, the locking sleeve matches the first movable groove, and the third gear and the fourth gear are located inside a second movable groove of the cylinder base.

[0010] Preferably, the first piston is slidably connected to the piston rod, and the second piston is slidably connected to the cylinder.

[0011] Preferably, the lead screw nut is provided with an internal thread matching the external thread of the lead screw.

[0012] Preferably, the locking member is a plug, the bottom of the cylinder seat is provided with a fixing groove matching the locking member, and the fixing groove is provided with an internal thread matching the external thread of the locking member.

[0013] Preferably, the first gear, the second gear, the third gear and the fourth gear are all bevel gears.

[0014] Therefore, the present invention adopts a digital hydraulic cylinder with the above structure, which has the following beneficial effects:

[0015] 1) The rotation speed and number of turns of the lead screw can effectively transmit the speed and position of the piston rod, and then adjust the output flow through the digital valve to achieve accurate control of the piston rod, which is more stable and reliable than the magnetostrictive sensor;

[0016] 2) When the lead screw and the piston rod move relative to each other, the first piston can support the lead screw so that it does not move, thereby increasing its service life;

[0017] 3) By setting the locking piece, locking sleeve, and specially designed cylinder seat, it can effectively provide assembly space for the product and make the screw installation more convenient;

[0018] 4) The parallel setting of the digital valve and the piston rod shortens the installation distance between the components inside the hydraulic cylinder and saves axial space.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a side view of a digital hydraulic cylinder of the present invention;

[0021] Figure 2 It is a side cross-sectional view of a digital hydraulic cylinder of the present invention;

[0022] Figure 3 It is an enlarged view of part A of a digital hydraulic cylinder of the present invention.

[0023] Reference numerals

[0024] 1. Cylinder barrel; 2. Cylinder seat; 3. Piston rod; 4. First piston; 5. Screw; 6. Second piston; 7. First gear; 8. Second gear; 9. Digital valve; 10. Third gear; 11. First bearing; 12. Screw nut; 13. Second bearing; 14. Transmission rod; 15. Fourth gear; 16. First oil port; 17. Locking sleeve; 18. Locking piece; 19. Fixed groove; 20. First movable groove; 21. Second movable groove. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Figure 1 This is a side view of a digital hydraulic cylinder of the present invention. Figure 2 It is a side cross-sectional view of a digital hydraulic cylinder of the present invention. Figure 3This is an enlarged view of the A part of a digital hydraulic cylinder of the present invention. As shown in the figure, a digital hydraulic cylinder includes a cylinder barrel 1 and a cylinder base 2. A hollow piston rod 3 is arranged inside the cylinder barrel 1. One end of the piston rod 3 is connected to the first bearing 11 at the top of the lead screw 5 through the first piston 4, and the other end of the piston rod 3 is connected to the lead screw nut 12 on the lead screw 5 through the second piston 6. The lead screw 5 is connected to the second bearing 13 inside the cylinder base 2 outside the second piston 6. A first gear 7 is arranged at the end of the lead screw 5. The first gear 7 is meshed with the second gear 8 at the top of the transmission rod 14 inside the cylinder base 2, and the third gear 10 at the bottom of the transmission rod 14 is meshed with the fourth gear 15 on the digital valve 9. The digital valve 9 is connected to the cylinder base 2, and the cylinder barrel 1 is provided with a first oil port 16 and a second oil port. The first oil port 16 and the second oil port are both connected to the digital valve 9. The cylinder barrel 1 and the cylinder base 2 are integrally formed, and the piston rod 3 can move relative to the cylinder barrel 1, and the lead screw 5 moves relative to the piston rod 3. When the piston rod 3 moves, the lead screw 5 rotates driven by the piston rod 3. The first gear 7 rotates with the lead screw 5, the first gear 7 drives the second gear 8 to rotate, the second gear 8 drives the third gear 10 to rotate through the transmission rod 14, and the third gear 10 drives the fourth gear 15 to rotate. The fourth gear 15 transmits the rotation of the lead screw 5 to the digital valve 9, and the digital valve 9 can adjust the output flow, thereby controlling the moving position and signal of the piston rod 3. The speed and position of the piston rod 3 can be transmitted by the rotation speed and number of turns of the lead screw 5, ensuring the precise control of the piston rod 3 by the digital valve 9.

[0028] The first bearing 11 and the second bearing 13 are provided to ensure that the lead screw 5 rotates smoothly with the piston rod 3 and limit the movement direction of the lead screw 5. The first piston 4 is provided to provide support for the lead screw 5 when sliding relative to the piston rod 3, to ensure that the lead screw 5 does not move, and to increase its service life. The second piston 6 is provided so that when the second piston 6 moves with the piston rod 3, the lead screw nut 12 moves along the lead screw 5 driven by the second piston 6, and at the same time, the lead screw nut 12 limits the movement direction of the lead screw 5. The digital valve 9 is connected to the first oil port 16 and the second oil port, and can control the flow direction and flow amount of the hydraulic oil in the cylinder 1 at both ends of the piston rod 3, so as to realize the accurate control of the piston rod 3 by the digital valve 9, which is stable and reliable compared with the magnetostrictive sensor.

[0029] There are two second bearings 13, and a bearing spacer is provided between the second bearings 13. The second bearing 13 near the first gear 7 is connected to the locking sleeve 17, and the locking piece 18 of the locking sleeve 17 is connected to the cylinder seat 2. The locking sleeve 17 fixes the position of the second bearing 13, and the locking piece 18 assists the locking sleeve 17 to lock and fix the second bearing 13. During assembly, the lead screw 5 is first extended from the fixing groove 19 at one end of the cylinder seat 2, and the second bearing 13, the bearing spacer, the second bearing 13, the first gear 7 and the locking sleeve 17 are installed in sequence. After the lead screw 5 is returned to its position, the locking piece 18 locks the locking sleeve 17, making it easier to install the lead screw 5.

[0030] The second bearing 13 near the side of the lead screw nut 12 is connected to the limit block, and the limit block is connected to the cylinder seat 2. The setting of the limit block cooperates with the cylinder seat 2 so that the lead screw 5 is axially fixed relative to the cylinder seat 2.

[0031] The transmission rod 14 is connected to the cylinder base 2 through the third bearing, the angle between the transmission rod 14 and the lead screw 5 is 90°, and the angle between the digital valve 9 and the piston rod 3 is 180°. The angle setting between the digital valve 9 and the piston rod 3, in conjunction with the setting of the position of the first gear 7 and the transmission rod 14, can shorten the installation length and save the axial space inside the cylinder base 2.

[0032] The first gear 7 and the second gear 8 are located inside the first moving groove 20 of the cylinder base 2, the locking sleeve 17 matches the first moving groove 20, and the third gear 10 and the fourth gear 15 are located inside the second moving groove 21 of the cylinder base 2. The setting of the first moving groove 20 and the second moving groove 21 leaves assembly space for the first gear 7, the second gear 8, the third gear 10 and the fourth gear 15 to ensure their smooth operation.

[0033] The first piston 4 is slidably connected to the piston rod 3 , and the second piston 6 is slidably connected to the cylinder 1 .

[0034] The lead screw nut 12 is provided with an internal thread matching the external thread of the lead screw 5 .

[0035] The locking member 18 is a plug, and a fixing groove 19 matching the locking member 18 is provided at the bottom of the cylinder base 2, and the fixing groove 19 is provided with an internal thread matching the external thread of the locking member 18. After the locking member 18 is connected to the fixing groove 19 of the cylinder base 2, the moving direction of the lead screw 5 is axially positioned.

[0036] The first gear 7, the second gear 8, the third gear 10 and the fourth gear 15 are all bevel gears.

[0037] When in use, when the digital valve 9 controls the hydraulic oil to enter the cylinder 1 from the first oil port 16, the second piston 6 and the piston rod 3 are pushed outward. When the piston rod 3 and the second piston 6 move, the lead screw 5 rotates accordingly, driving the first gear 7 thereon to rotate. The first gear 7 drives the transmission rod 14 to rotate through the second gear 8, and the transmission rod 14 drives the fourth gear 15 to rotate through the third gear 10. After the rotation of the lead screw 5 is transmitted to the digital valve 9, the digital valve 9 adjusts the output flow to control the position and movement speed of the piston rod 3. When the oil enters from the second oil port, the rotation direction is different, and the principle is the same as that of entering the oil from the first oil port 16.

[0038] Therefore, the present invention adopts a digital hydraulic cylinder with the above structure, the rotation speed and number of turns of the lead screw can effectively transmit the speed and position of the piston rod, and then the output flow is adjusted by the digital valve to achieve accurate control of the piston rod, which is more stable and reliable than the magnetostrictive sensor; when the lead screw and the piston rod move relative to each other, the first piston can support the lead screw so that it will not move, thereby improving the service life; by arranging a locking piece, a locking sleeve, and a specially designed cylinder seat, an assembly space for the product can be effectively provided, making the lead screw installation more convenient; the parallel arrangement of the digital valve and the piston rod shortens the installation distance between the internal components of the hydraulic cylinder and saves axial space.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A digital hydraulic cylinder, characterized in that: It comprises a cylinder barrel and a cylinder seat, wherein a hollow piston rod is arranged in the cylinder barrel, one end of the piston rod is connected to a first bearing at the top end of a lead screw through a first piston, and the other end of the piston rod is connected to a lead screw nut on the lead screw through a second piston, and the lead screw is connected to a second bearing inside the cylinder seat at the outside of the second piston, a first gear is arranged at the end of the lead screw, the first gear is meshed with a second gear at the top end of a transmission rod inside the cylinder seat, a third gear at the bottom end of the transmission rod is meshed with a fourth gear on a digital valve, and the digital valve is connected to the cylinder seat, and the cylinder barrel is provided with a first oil port and a second oil port, and both the first oil port and the second oil port are connected to the digital valve; There are two second bearings, a bearing spacer is provided between the second bearings, the second bearing close to the first gear is connected to a locking sleeve, and the locking piece of the locking sleeve is connected to the cylinder seat; The first gear and the second gear are located in the first moving groove of the cylinder base, the locking sleeve matches the first moving groove, and the third gear and the fourth gear are located in the second moving groove of the cylinder base; The locking piece is a plug, the bottom of the cylinder seat is provided with a fixing groove matching the locking piece, and the fixing groove is provided with an internal thread matching the external thread of the locking piece.

2. A digital hydraulic cylinder according to claim 1, characterized in that: The second bearing close to one side of the lead screw nut is connected to a limit block, and the limit block is connected to the cylinder seat.

3. A digital hydraulic cylinder according to claim 1, characterized in that: The transmission rod is connected to the cylinder seat via a third bearing, the angle between the transmission rod and the lead screw is 90°, and the angle between the digital valve and the piston rod is 180°.

4. A digital hydraulic cylinder according to claim 1, characterized in that: The first piston is slidably connected to the piston rod, and the second piston is slidably connected to the cylinder.

5. A digital hydraulic cylinder according to claim 1, characterized in that: The lead screw nut is provided with an internal thread matching the external thread of the lead screw.

6. A digital hydraulic cylinder according to claim 1, characterized in that: The first gear, the second gear, the third gear and the fourth gear are all bevel gears.

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