One-way pressure maintaining hydraulic nut

Abstract

The utility model provides a one-way pressure maintaining hydraulic nut, and relates to the technical field of roller manufacturing. The hydraulic nut comprises a hydraulic nut inner ring, a hydraulic nut outer ring and a locking ring, the hydraulic nut inner ring is sleeved with the hydraulic nut outer ring and the locking ring side by side, and an oil injection cavity which expands or shrinks along with relative movement between the hydraulic nut outer ring and the hydraulic nut inner ring is formed between the hydraulic nut outer ring and the hydraulic nut inner ring. A pressurizing oil hole communicated with the outside and the oil injection cavity is formed in the inner ring of the hydraulic nut, one or more one-way pressure maintaining balls are arranged in the pressurizing oil hole, the hole diameter of the pressurizing oil hole from the middle to the bottom is gradually increased, and the diameter of the one-way pressure maintaining balls is larger than the minimum hole diameter of the pressurizing oil hole and smaller than the hole diameter of the bottom. Through the collaborative structural design of the conical pressing oil hole and the one-way pressure maintaining ball, the loss of hydraulic pressure in the hydraulic nut is reduced, and the service life of the hydraulic nut is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of rolling mill manufacturing technology, and in particular to a hydraulic nut with unidirectional pressure holding. Background Technology

[0002] In composite rollers, the hydraulic nut is a key component ensuring a tight fit between the roller ring and the roller shaft. Traditional hydraulic nuts convert hydraulic pressure into an axial tightening force on the roller ring and rely on their internal threads to maintain pressure after depressurization. However, in composite roller applications, the internal threads of the hydraulic nut need to withstand hydraulic rebound forces from the roller ring, which can reach up to 2000 kN. The commonly used M280×4 threads in existing technologies often fail due to insufficient strength, preventing the hydraulic nut from maintaining continuous pressure. This leads to roller ring rotation, affecting the stability and service life of the equipment. Utility Model Content

[0003] To address the aforementioned problems, this utility model proposes a unidirectional pressure-holding hydraulic nut.

[0004] The technical solution adopted in this utility model is as follows:

[0005] This utility model discloses a one-way pressure-holding hydraulic nut, including an inner ring, an outer ring, and a locking ring. The outer ring and the locking ring are mounted side-by-side on the inner ring. The outer ring and the inner ring are slidably connected. The locking ring is threadedly connected to the inner ring. An oil injection cavity is provided between the outer and inner rings, which expands or contracts with the relative movement between them. The inner ring has a pressure-pressing oil hole connecting to the outside and the oil injection cavity. One or more one-way pressure-holding balls are provided in the pressure-pressing oil hole. The diameter of the pressure-pressing oil hole gradually increases from the middle to the bottom. The diameter of the one-way pressure-holding ball is larger than the minimum diameter of the pressure-pressing oil hole but smaller than the bottom diameter.

[0006] During use, pressure is applied to the oil injection chamber by an external power source. During the pressure application process, the external oil pressure pushes open the one-way pressure-holding ball, and the oil enters the oil injection chamber, causing axial relative movement between the inner and outer rings of the hydraulic nut. After the pressure is released, the oil pressure in the oil injection chamber causes the one-way pressure-holding ball to press tightly against the tapered wall of the pressure oil hole, forming a one-way seal.

[0007] Preferably, the taper of the portion of the pressure oil hole that gradually increases in diameter is 4-6° to prevent the one-way pressure-holding ball from falling off.

[0008] Preferably, the inner wall smoothness of the portion of the pressure oil hole with gradually increasing diameter is 0.1 or higher, so as to increase the fit between the inner wall of the pressure oil hole and the one-way pressure holding ball and ensure the sealing of the oil injection cavity.

[0009] Preferably, the unidirectional pressure-holding ball includes a main force-bearing unidirectional pressure-holding ball and a backup unidirectional pressure-holding ball. The main force-bearing unidirectional pressure-holding ball has a larger diameter than the backup unidirectional pressure-holding ball and is located at the bottom of the backup unidirectional pressure-holding ball. The backup unidirectional pressure-holding ball can automatically take over when the main force-bearing unidirectional pressure-holding ball fails, thus achieving double insurance.

[0010] Preferably, when the one-way pressure-holding ball is in close contact with the inner wall of the pressure-pressurizing oil hole, the bottom of the one-way pressure-holding ball is 1mm or more away from the bottom of the pressure-pressurizing oil hole, so as to ensure that the oil can pass smoothly through the injection chamber without being blocked by the one-way pressure-holding ball when pressurized.

[0011] Preferably, the inner ring of the hydraulic nut includes a first inner ring segment with a larger outer diameter and a second inner ring segment with a smaller outer diameter, and the inner ring of the hydraulic nut is provided with internal threads; the outer ring of the hydraulic nut is machined along the axis with a first inner hole that matches the first inner ring segment, and the bottom surface of the first inner hole is machined with a second inner hole that matches the second inner ring segment; the stepped shaft structure design allows the oil injection chamber space to shrink or increase when the inner ring and outer ring of the hydraulic nut move relative to each other, and conversely, when pressure is applied to the oil injection chamber, it can also push the inner ring and outer ring of the hydraulic nut to move relative to each other.

[0012] Preferably, a first sealing ring group is provided between the first inner ring segment and the outer ring of the hydraulic nut, and a second sealing ring group is provided between the second inner ring segment and the outer ring of the hydraulic nut. The first sealing ring group and the second sealing ring group are used to enhance the sealing performance of the oil injection chamber.

[0013] Preferably, the top end of the first inner hole of the outer ring of the hydraulic nut and the top end of the second inner ring section of the inner ring of the hydraulic nut are chamfered to prevent scratching the sealing ring during assembly and to ensure the sealing performance of the oil injection chamber under high pressure.

[0014] Preferably, the first sealing ring group and the second sealing ring group each include two sealing rings, and the double sealing ring configuration can enhance the sealing performance of the oil injection chamber.

[0015] Preferably, the side curved surface of the locking ring is designed with multiple countersunk threaded through holes to prevent the locking ring from loosening and improve the stability of the threaded connection.

[0016] This utility model adopts a conical pressure-pressing oil hole and sets a rigid ball inside the hole to form a one-way pressure-holding structure, which avoids oil leakage in the oil injection chamber and reduces hydraulic pressure loss, thereby solving the problem that the hydraulic nut cannot maintain pressure continuously; the design of double one-way pressure-holding balls provides double insurance for the sealing of the oil injection chamber, greatly improves reliability, and greatly extends the sealing life; the overall structure is simple and reliable, easy to maintain, and suitable for various composite roller assembly conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a unidirectional pressure-holding hydraulic nut according to the present invention;

[0018] Figure 2 This is a cross-sectional view of a hydraulic nut with unidirectional pressure holding according to this utility model.

[0019] Reference numerals: 1-Inner ring of hydraulic nut, 2-Outer ring of hydraulic nut, 3-Locking ring, 4-First sealing ring group, 5-Second sealing ring group, 6-Oil injection chamber, 7-Pressure oil hole, 8-Counterhead threaded through hole. Detailed Implementation

[0020] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0021] The following description, in conjunction with the accompanying drawings, further illustrates a unidirectional pressure-holding hydraulic nut of this utility model.

[0022] like Figure 1 and Figure 2 As shown, in this embodiment, the hydraulic nut includes an inner ring 1, an outer ring 2, and a locking ring 3. The outer ring 2 and the locking ring 3 are mounted side-by-side on the inner ring 1. The outer ring 2 and the inner ring 1 are slidably connected, and the locking ring 3 is threadedly connected to the inner ring 1. The inner ring 1 has an internal thread of M190×6, which mates with the M190×6 thread on the composite roller shaft. The thread between the locking ring 3 and the inner ring 1 is M280×4. The inner ring 1 has a stepped shaft structure, including a first inner ring segment with a larger outer diameter and a second inner ring segment with a smaller outer diameter, both segments having the same inner diameter. The outer ring 2 has a first inner hole along its axis that matches the first inner ring segment. The first inner hole is a blind hole. The bottom surface of the first inner hole has a second inner hole that matches the second inner ring segment. The second inner hole is a through hole.

[0023] The inner ring 1 of the hydraulic nut has a pressure-pressurizing oil hole 7 on its curved side for injecting oil into the oil injection chamber 6. The pressure-pressurizing oil hole 7 is a through hole and connects to an external power source. One or more one-way pressure-holding balls are placed inside the pressure-pressurizing oil hole 7. In this embodiment, two one-way pressure-holding balls are designed and arranged along the central axis of the pressure-pressurizing oil hole 7. The bottom inner wall of the pressure-pressurizing oil hole 7 is designed with a 5° taper, and the inner diameter gradually increases from the middle to the bottom of the pressure-pressurizing oil hole 7 to prevent the one-way pressure-holding balls from detaching from the pressure-pressurizing oil hole 7. The bottom inner wall of the pressure-pressurizing oil hole 7 has a surface finish of 0.1 or higher. When the one-way pressure-holding balls are in close contact with the inner wall of the pressure-pressurizing oil hole 7, the distance between the bottom of the one-way pressure-holding balls and the bottom of the pressure-pressurizing oil hole 7 is 1 mm or more. The top inner wall of the pressure-pressurizing oil hole 7 is designed with an internal thread, specifically a G1 / 8 pipe thread, which mates with the interface of the external power source.

[0024] When an external power source injects oil into the oil injection chamber 6, the liquid pressure inside the external power source is greater than the liquid pressure inside the oil injection chamber 6. The one-way pressure-holding ball detaches from the inner wall of the pressure-pressurizing oil hole 7, allowing the oil to flow smoothly through the pressure-pressurizing oil hole 7 into the oil injection chamber 6. When the external power source reduces the pressure, the liquid pressure inside the oil injection chamber 6 becomes greater than the external air pressure. The one-way pressure-holding ball, under the pressure difference, adheres tightly to the inner wall of the pressure-pressurizing oil hole 7, making the oil injection chamber 6 a sealed pressure-holding space. This prevents oil leakage from the oil injection chamber 6 and maintains the pressure. At this point, the external power source can completely depressurize and disconnect from the pressure-pressurizing oil hole 7. In this embodiment, of the two one-way pressure-holding balls, the one closer to the bottom of the pressure-pressurizing oil hole 7 is the main force-bearing one-way pressure-holding ball, and the other is a spare one-way pressure-holding ball, which is slightly smaller in diameter than the main force-bearing one-way pressure-holding ball. When the main force-bearing one-way pressure-holding ball fails, the oil in the oil injection chamber 6 seeps between the two one-way pressure-holding balls. The hydraulic pressure in the oil injection chamber 6 will push the spare one-way pressure-holding ball to fit tightly against the inner wall of the pressure oil hole 7, ensuring that the airtightness of the oil injection chamber 6 is not affected.

[0025] The locking ring 3 is threaded onto the first inner ring section of the hydraulic nut inner ring 1, with its side surface tightly against the hydraulic nut outer ring 2. The side curved surface of the locking ring 3 is designed with multiple countersunk threaded through holes 8. By screwing screws into the countersunk threaded through holes 8, the radial pressure of the locking ring 3 on the hydraulic nut inner ring 1 is increased, thereby improving the safety factor of the locking ring 3 and preventing the locking ring 3 from loosening.

[0026] A first sealing groove is provided on the outer wall of the first inner ring segment of the hydraulic nut inner ring 1 for installing the first sealing ring group 4 between the first inner ring segment and the hydraulic nut outer ring 2; a second sealing groove is provided on the inner wall of the second inner hole of the hydraulic nut outer ring 2 for installing the second sealing ring group 5 between the second inner ring segment and the hydraulic nut outer ring 2. The space formed between the hydraulic nut inner ring 1, the hydraulic nut outer ring 2, the first sealing ring group 4, and the second sealing ring group 5 is an oil injection chamber 6. Both the first sealing ring group 4 and the second sealing ring group 5 include multiple sealing rings. In this embodiment, both the first sealing ring group 4 and the second sealing ring group 5 include two sealing rings, and all sealing rings are made of graphite ceramic fiber fluororubber. At the entrances of the first sealing ring group 4 and the second sealing ring group 5, i.e., the top of the first inner hole of the hydraulic nut outer ring 2 and the top of the second inner ring segment of the hydraulic nut inner ring 1, a 15° chamfer is designed to prevent the structural edges from scratching the sealing rings during assembly, which could lead to the sealing rings breaking during pressure testing.

[0027] The assembly method of the hydraulic nut in the composite roller includes the following steps.

[0028] S1. Install the first sealing ring group 4 and the second sealing ring group 5 in the first sealing groove and the second sealing groove respectively. Assemble the hydraulic nut inner ring 1 and the hydraulic nut outer ring 2 and screw them to the thread of the composite roller shaft. Connect the pressure oil hole 7 to the external pressure pump.

[0029] S2. Keep the height of the oil injection chamber 6 at 1mm or above, start the external pressure pump, and pressurize the oil injection chamber 6 through the external pressure pump. At this time, the inner ring 1 of the hydraulic nut will not move by default because it has an M190×6 threaded connection with the composite roller shaft. When pressurizing, the pressure of the pressure pump is greater than the internal pressure of the oil injection chamber 6. The pressure difference causes the one-way pressure holding ball to detach from the inner wall of the pressure oil hole 7, so that the oil is injected into the oil injection chamber 6 through the pressure oil hole 7.

[0030] S3. After the pressure in the oil filling chamber 6 reaches the design pressure, install and tighten the locking ring 3, and install and tighten the screw in the countersunk threaded through hole 8 of the locking ring 3.

[0031] S4. Adjust the pressure pump to decrease by 0.1MPa. At this time, the pressure in the oil injection chamber 6 is greater than the pressure of the pressure pump. The pressure difference pushes the two one-way pressure holding balls outward, making the inside of the oil injection chamber 6 completely sealed.

[0032] S5. The external pressure pump is completely depressurized. At this time, the internal pressure of the oil injection chamber 6 is much greater than that of the outside. The internal pressure makes the one-way pressure holding ball stick tightly to the inner wall of the pressure oil hole 7, and maintain the designed hydraulic pressure at all times.

[0033] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the design concept of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hydraulic nut for one-way pressure retention, characterized by, The hydraulic nut inner ring, the hydraulic nut outer ring and the locking ring are arranged side by side on the hydraulic nut inner ring, the hydraulic nut outer ring is in sliding connection with the hydraulic nut inner ring, the locking ring is in threaded connection with the hydraulic nut inner ring, an oil injection cavity is arranged between the hydraulic nut outer ring and the hydraulic nut inner ring and expands or shrinks with the relative movement between the hydraulic nut outer ring and the hydraulic nut inner ring, the hydraulic nut inner ring is provided with a pressing oil hole which is in communication with the outside and the oil injection cavity, one or more one-way pressure maintaining balls are arranged in the pressing oil hole, the diameter of the pressing oil hole gradually increases from the middle part to the bottom part, and the diameter of the one-way pressure maintaining ball is greater than the minimum diameter of the pressing oil hole and smaller than the bottom diameter.

2. The hydraulic nut of claim 1, wherein, The taper of the gradually increasing diameter part of the pressing oil hole is 4-6°.

3. The hydraulic nut of claim 1, wherein, The inner wall smoothness of the gradually increasing diameter part of the pressing oil hole is 0.1 or above.

4. The hydraulic nut of claim 1, wherein, The one-way pressure maintaining ball comprises a main force one-way pressure maintaining ball and a standby one-way pressure maintaining ball, the diameter of the main force one-way pressure maintaining ball is greater than that of the standby one-way pressure maintaining ball and is located at the bottom of the standby one-way pressure maintaining ball.

5. The hydraulic nut of claim 1, wherein, When the one-way pressure maintaining ball is in close contact with the inner wall of the pressing oil hole, the distance between the bottom of the one-way pressure maintaining ball and the bottom of the pressing oil hole is 1mm or above.

6. The hydraulic nut of claim 1, wherein, The hydraulic nut inner ring comprises a first inner ring section with a larger outer diameter and a second inner ring section with a smaller outer diameter, and the hydraulic nut inner ring is provided with an internal thread; the hydraulic nut outer ring is processed along the axis and is provided with a first inner hole matched with the first inner ring section, and the bottom surface of the first inner hole is processed and provided with a second inner hole matched with the second inner ring section.

7. The hydraulic nut of claim 6, wherein, A first sealing ring group is arranged between the first inner ring section and the hydraulic nut outer ring, and a second sealing ring group is arranged between the second inner ring section and the hydraulic nut outer ring, and the first sealing ring group and the second sealing ring group are used to enhance the sealing performance of the oil injection cavity.

8. The hydraulic nut of claim 7, wherein, The top end of the first inner hole of the hydraulic nut outer ring and the top end of the second inner ring section of the hydraulic nut inner ring are provided with chamfers.

9. The hydraulic nut of claim 7, wherein, The first sealing ring group and the second sealing ring group each comprise two sealing rings.

10. The hydraulic nut of claim 1, wherein, The side curved surface of the locking ring is designed with a plurality of countersunk threaded through holes.

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