Hydraulic Cylinders

Abstract

The present invention relates to a hydraulic cylinder, comprising: a cylinder body (1); a piston rod (2), which can extend from the first end of the cylinder body (1) and has a center hole extending along its axial direction; a motion conversion mechanism, comprising a screw rod (3) and a screw sleeve threadedly matched with the screw rod (3), the first end of the screw rod (3) being rotatably mounted on the bottom wall of the second end of the cylinder body (1), the second end of the screw rod (3) extending into the center hole of the piston rod (2), and the screw sleeve being connected to the piston rod (2); a first bearing (4), which is sleeved on the screw rod (3) and mounted in a first bearing hole (14) on the bottom wall of the second end of the cylinder body (1); and a detection component (10), which is used to detect the rotation amount of the screw rod (3) to obtain the movement amount of the piston rod (2). By applying the technical solution of the present invention, the screw rod is mounted on the cylinder body through the bearing, which improves the problem that the screw rod fixing method in the prior art makes the rotation resistance of the screw rod large.

Description

Technical Field

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

[0002] Figure 1 A schematic diagram of the structure of a hydraulic cylinder capable of measuring the moving position of a piston is shown. Figure 1 As shown, the hydraulic cylinder of the related art includes a piston 6, a piston rod 23, a cylinder body 4, a front sealing cover 9, a rear sealing cover 1 and a position sensing device. The front sealing cover 9 and the rear sealing cover 1 are both provided with a central through hole, and are both locked on the port of the cylinder body 4 by bolts. The piston rod 23 is provided with a central hole. The piston rod 23 is slidably matched with the front sealing cover 9. The position sensing device includes a screw 7, a screw sleeve 5 and an angular displacement sensor (a magnetically encoded angular displacement sensor is selected, including a marking body 17 and a sensor probe 20), 18, the screw 7 is located in the center hole 10 of the piston rod 23, and there is a radial gap between the screw 7 and the center hole 10 of the piston rod 23. The rear end of the screw 5 exposes the rear end sealing cover 1, and the rear end of the screw 7 is provided with a locking nut 18. The screw sleeve 5 is fastened to the rear end of the piston rod 23, and the screw sleeve 5 is sleeved on the screw 7 and is threadedly connected to the screw 7. A thrust step 71 is provided at the rear of the screw 7, and the thrust step 71 abuts against the inner wall of the rear end sealing cover 1. A tension cover 13 is fastened on the rear end sealing cover 1. The tension cover 13 is sleeved on the rear of the screw 7 and pressed on the thrust step 71, so as to prevent the screw 7 from moving axially. The cylinder sleeve 4, the front end sealing cover 9, the rear end sealing cover 1, the piston rod 23, the screw 7 and the tension cover 13 are all coaxial. The angular displacement sensor is arranged outside the cylinder body and connected to the rear end of the screw 7. The angular displacement sensor uses an existing magnetic encoding angular displacement sensor (it can also be a photoelectric encoding angular displacement sensor, etc.), the marking body 17 is fixedly connected to the rear end of the screw 7, and the sensor probe 20 is connected to the marking body 17. The signal output line of the sensor probe 20 is connected to an external measuring instrument, and the measuring instrument uses an existing measuring instrument. Reference numeral 11 is the front end connector of the piston rod 23, reference numeral 19 is the external connector of the rear end sealing cover 1, reference numerals 3 and 8 are the liquid inlet and outlet respectively, reference numerals 12 and 26 are sealing rings, reference numeral 15 is a labyrinth seal, the function of the labyrinth seal 15 is to allow the pressure head of the hydraulic cylinder to drop before reaching the sealing ring 26, to prevent the pressure in the hydraulic cylinder cavity from being too high so that the sealing ring 26 is pressed tightly against the screw 7, thereby avoiding greater resistance to the rotation of the screw 7, and effectively preventing severe wear of the sealing ring 26 and greater deformation of the screw 7 due to torsional force.

[0003] 1. The axial fixation of the screw rod adopts direct contact and compression of the tension cover 13, which has large friction, large resistance to screw rotation and is easy to wear; when the cylinder retracts, the screw sleeve 5 directly contacts the tension cover 13 as the force contact surface, and long-term work can easily cause damage to the tension cover 13.

[0004] 2. The measuring part includes a marker and a sensor probe, which are directly arranged outside the cylinder body and are easily affected by the external environment, resulting in inaccurate measurement results. The optical encoding angular displacement sensor or magnetic encoding angular displacement sensor used in this part is costly and not very practical. Summary of the invention

[0005] The present invention aims to provide a hydraulic cylinder to improve the problem in the prior art that the fixing method of the screw rod causes greater rotation resistance of the screw rod.

[0006] According to one aspect of an embodiment of the present invention, the present invention provides a hydraulic cylinder, the hydraulic cylinder comprising:

[0007] Cylinder body;

[0008] A piston rod, which can extend from the first end of the cylinder body and has a central hole extending along its axial direction;

[0009] The motion conversion mechanism includes a screw and a screw sleeve matched with the screw thread, the first end of the screw is rotatably mounted on the bottom wall of the second end of the cylinder body, the second end of the screw extends into the center hole of the piston rod, and the screw sleeve is connected to the piston rod;

[0010] A first bearing is sleeved on the screw rod and installed in a first bearing hole on the bottom wall of the second end of the cylinder body;

[0011] The detection component is used to detect the rotation amount of the screw to obtain the movement amount of the piston rod.

[0012] Optionally, a through hole connecting the inner cavity of the cylinder body and the first bearing hole is provided on the bottom wall, the first end of the screw passes through the through hole and is connected to the first bearing, and an end of the through hole adjacent to the first bearing hole is provided with a first limiting step for limiting the axial movement of the first bearing along the first bearing hole.

[0013] Optionally, the hydraulic cylinder further comprises a first retaining ring, which is arranged on a side of the first bearing away from the first limiting step to limit the axial movement of the first bearing along the first bearing hole.

[0014] Optionally, the first end of the screw rod is provided with a thread, and the hydraulic cylinder further comprises a nut matched with the thread, and the nut is located on a side of the first retaining ring facing away from the first bearing, so that the first retaining ring abuts against the first bearing.

[0015] Optionally, a slot is provided on the inner wall of the first bearing hole or on the screw rod, and the first retaining ring is clamped in the slot.

[0016] Optionally, the hydraulic cylinder further comprises a housing, a housing cover is arranged at the second end of the cylinder body, and the detection component is arranged in the housing.

[0017] Optionally, the hydraulic cylinder further comprises:

[0018] A rotating shaft connected to the screw;

[0019] The second bearing is sleeved on the rotating shaft;

[0020] The bearing seat is provided with a second bearing hole matched with the second bearing and is connected to the cylinder body. The detection component is arranged on a side of the bearing seat away from the screw.

[0021] Optionally, a concave cavity is provided on the end surface of the second end of the cylinder body, the first bearing hole is provided at the bottom of the concave cavity, and the bearing seat is provided in the concave cavity.

[0022] Optionally, a second limiting step is provided at the first end of the second bearing hole, and the second limiting step is used to limit the axial movement of the second bearing, and a second retaining ring is provided on a side of the second bearing away from the second limiting step.

[0023] Optionally, the hydraulic cylinder further includes a transmission, which includes an input end connected to the rotating shaft and an output end connected to the detection component.

[0024] By applying the technical solution of the present invention, the screw is installed on the cylinder body through the bearing, which improves the problem in the prior art that the fixing method of the screw causes greater rotation resistance of the screw.

[0025] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 A schematic diagram showing the structure of a hydraulic cylinder in the prior art; and

[0028] Figure 2 A structural schematic diagram of a hydraulic cylinder according to an embodiment of the present invention is shown.

[0029] In the figure:

[0030] 1. Cylinder body; 2. Piston rod; 3. Screw; 4. First bearing; 5. Nut; 6. Rotating shaft; 7. Bearing seat; 8. Transmission; 9. Controller; 10. Detection component; 11. Housing; 12. Second bearing; 13. Second retaining ring; 14. First bearing hole; 15. First retaining ring; 16. Sealing ring. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Figure 2 FIG. 2 shows a schematic diagram of the structure of the hydraulic cylinder of this embodiment. Figure 2 As shown, the hydraulic cylinder of this embodiment comprises a cylinder body 1, a piston rod 2 movably arranged in the cylinder body 1, and a motion conversion mechanism. The piston rod 2 can extend from the first end of the cylinder body 1, and the piston rod 2 is provided with a central hole extending along its axial direction.

[0033] The motion conversion mechanism includes a screw rod 3 and a screw sleeve threadedly matched with the screw rod 3. The first end of the screw rod 3 is rotatably mounted on the bottom wall of the second end of the cylinder body 1. The second end of the screw rod 3 extends into the center hole of the piston rod 2, and the screw sleeve is connected to the piston rod 3. The hydraulic cylinder also includes a first bearing 4, which is sleeved on the screw rod 3 and installed in a first bearing hole 14 on the bottom wall of the second end of the cylinder body 1.

[0034] When the piston rod 3 moves along the axial direction of the cylinder body 1, the screw sleeve moves with the piston rod 3, and the piston rod 3 is driven to rotate during the rotation of the screw sleeve.

[0035] The hydraulic cylinder further includes a detection component 10, which is used to detect the rotation amount of the screw rod 3 to obtain the movement amount of the piston rod 2. Optionally, the detection component 10 includes one of an angle sensor and an encoder.

[0036] A through hole connecting the inner cavity of the cylinder body 1 and the first bearing hole 14 is provided on the bottom wall of the second end of the cylinder body 1. The first end of the screw rod 3 passes through the above-mentioned through hole and is connected to the first bearing 4. An end of the first bearing hole 14 adjacent to the above-mentioned through hole is provided with a first limiting step for limiting the axial movement of the first bearing 4 along the first bearing hole 14.

[0037] The hydraulic cylinder further includes a sealing ring 16 , which is sleeved on the screw rod 3 and located in the above-mentioned through hole to seal the inner cavity of the cylinder body 1 .

[0038] The hydraulic cylinder further includes a first retaining ring 15 , which is disposed on a side of the first bearing 4 away from the first limiting step to limit the axial movement of the first bearing 4 along the first bearing hole 14 .

[0039] The first end of the screw rod 3 is provided with a thread, and the hydraulic cylinder further comprises a nut 5 matched with the thread. The nut 5 is located on the side of the first retaining ring 15 facing away from the first bearing 4 so that the first retaining ring 15 abuts against the first bearing 4 .

[0040] A clamping groove is provided on the inner wall of the first bearing hole 14 or on the screw rod 3 , and the first retaining ring 15 is clamped in the clamping groove.

[0041] The hydraulic cylinder further comprises a housing 11 , which is covered at the second end of the cylinder body 1 , and the detection component 10 is arranged in the housing 11 .

[0042] The hydraulic cylinder further comprises a rotating shaft 6 connected to the screw rod 3, a second bearing 12 sleeved on the rotating shaft 6, and a bearing seat 7 for carrying the second bearing 12. The detection component 10 is arranged on a side of the bearing seat 7 away from the screw rod 3.

[0043] One end of the rotating shaft 6 is connected to the screw rod 3 , and the rotating shaft 6 extends from the screw rod 3 to a side of the bearing seat 7 away from the screw rod 3 . The detection component 10 detects the rotation amount of the rotating shaft 6 to obtain the movement amount of the piston rod 2 .

[0044] The bearing seat 7 is connected to the bottom wall of the second end of the cylinder body 1 and is provided with a second bearing hole adapted to the second shaft 12. A concave cavity is provided on the end surface of the second end of the cylinder body 1, the first bearing hole 14 is provided at the bottom of the concave cavity, and the bearing seat 7 is provided in the concave cavity.

[0045] A second limiting step is provided at the first end of the second bearing hole, and the second limiting step is used to limit the axial movement of the second bearing 12 . A second retaining ring 13 is provided on a side of the second bearing 12 away from the second limiting step.

[0046] The hydraulic cylinder further includes a transmission 8 , which includes an input end connected to the rotating shaft 6 and an output end connected to the detection component 10 .

[0047] In this embodiment, the first end of the screw rod 3 is rotatably mounted on the bottom wall of the second end of the cylinder body 1, the second end of the screw rod 3 extends into the central hole of the piston rod 2, the screw sleeve is connected to the piston rod 2, when the piston rod 2 moves along the cylinder body 1, the screw sleeve moves with the piston rod 2 and drives the screw rod 3 to rotate, the rotating shaft 6 rotates with the screw rod 3 and drives the reducer 8 to rotate. The detection component 10 detects the rotation amount of the power output end of the transmission 8 to obtain the movement amount of the piston rod 2.

[0048] The hydraulic cylinder further includes a controller 9 , which is electrically connected to the detection component 10 and is used to calculate the movement amount of the piston rod 2 according to the rotation amount detected by the detection component 10 .

[0049] The controller 9, the transmission 8 and the detection component 10 are all arranged in the housing 11, which is beneficial to protecting the above-mentioned components from being affected by the external environment and is beneficial to ensuring the accuracy of the detection results.

[0050] Optionally, the screw rod 3 includes a ball screw. The ball screw assembly adopts a mechanical structure to convert the linear motion of the piston rod 2 into rotational motion, which is simple and reliable, has a fast response, and can measure the length accurately.

[0051] The measuring mechanism of the hydraulic cylinder of this embodiment is mainly installed inside the hydraulic cylinder, and there is no interference problem with the outside world;

[0052] The piston rod movement measuring device of the hydraulic cylinder of this embodiment is a large-range length measuring device, which has an integrated large transmission ratio speed change mechanism inside, can meet the needs of different measurement lengths, has strong versatility, high reliability and low cost. The length measuring part is designed as an independent fully enclosed module with good sealing, strong environmental adaptability and easy installation, replacement and maintenance.

[0053] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic cylinder, characterized in that: include: Cylinder body (1); A piston rod (2) which can extend from the first end of the cylinder body (1) and has a central hole extending along its axial direction; A motion conversion mechanism, comprising a screw rod (3) and a screw sleeve threadably matched with the screw rod (3), wherein the first end of the screw rod (3) is rotatably mounted on the bottom wall of the second end of the cylinder body (1), the second end of the screw rod (3) extends into the central hole of the piston rod (2), and the screw sleeve is connected to the piston rod (2); A first bearing (4) is sleeved on the screw rod (3) and installed in a first bearing hole (14) on the bottom wall of the second end of the cylinder body (1); A detection component (10) is used to detect the rotation amount of the screw rod (3) to obtain the movement amount of the piston rod (2). The bottom wall is provided with a through hole communicating with the inner cavity of the cylinder body (1) and the first bearing hole (14); the first end of the screw rod (3) passes through the through hole and is connected to the first bearing (4); an end of the first bearing hole (14) adjacent to the through hole is provided with a first limiting step for limiting the axial movement of the first bearing (4) along the first bearing hole (14); It also comprises a first retaining ring (15), the first retaining ring (15) being arranged on a side of the first bearing (4) away from the first limiting step, so as to limit the axial movement of the first bearing (4) along the first bearing hole (14). A rotating shaft (6) connected to the screw rod (3); A second bearing (12) sleeved on the rotating shaft (6); The bearing seat (7) is provided with a second bearing hole matched with the second bearing (12) and is connected to the cylinder body (1). The detection component (10) is arranged on a side of the bearing seat (7) away from the screw rod (3). A concave cavity is provided on the end surface of the second end of the cylinder body (1), the first bearing hole (14) is provided at the bottom of the concave cavity, and the bearing seat (7) is provided in the concave cavity. A second limiting step is provided at the first end of the second bearing hole, the second limiting step being used to limit the axial movement of the second bearing (12), and a second retaining ring (13) is provided on a side of the second bearing (12) away from the second limiting step.

2. The hydraulic cylinder according to claim 1, characterized in that: The first end of the screw rod (3) is provided with a thread, and the hydraulic cylinder further comprises a nut (5) adapted to the thread, the nut (5) being located on a side of the first retaining ring (15) facing away from the first bearing (4), so that the first retaining ring (15) abuts against the first bearing (4).

3. The hydraulic cylinder according to claim 1, characterized in that: A slot is provided on the inner wall of the first bearing hole (14) or on the screw rod (3), and the first retaining ring (15) is retained in the slot.

4. The hydraulic cylinder according to claim 1, characterized in that: It also comprises a housing (11), wherein the housing (11) is covered on the second end of the cylinder body (1), and the detection component (10) is arranged in the housing (11).

5. The hydraulic cylinder according to claim 1, characterized in that: It also includes a transmission (8), wherein the transmission (8) includes an input end connected to the rotating shaft (6) and an output end connected to the detection component (10).

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