Cross bag with joint cross shaft and cross universal coupling

Abstract

The present invention discloses a cross pack with a joint cross shaft and a cross universal coupling, belonging to the technical field of couplings. The cross pack includes a cross shaft and a bearing; the inner ring of the bearing includes an inner ring body, and the inner ring body is interference-fitted with the shaft neck of the cross shaft, so that the outer ring of the bearing can rotate with the bearing rolling element; the inner ring body is cylindrical and extends to both sides along the central axis, respectively converging toward the axis to form a stop ring and expanding toward the axis to form a fitting portion; there is a fitting clearance between the inner side surface of the fitting portion and the shaft neck of the cross shaft, and a stop protrusion is formed on the outer side of the circumference thereof. A rotating sealing strip is provided between the outer ring of the bearing and the stop protrusion, and the rotating sealing strip is also matched with a lip-shaped sealing ring; the stop ring is in contact with the end face of the shaft head to limit the inner ring of the bearing in the axial direction. Without affecting the normal rotation of the bearing, the inner ring of the bearing is ensured to fit tightly with the shaft neck, ensuring that there is no oil leakage during use and ensuring that the use of the bearing is not affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of couplings, and more particularly, relates to a cross bag with a joint cross shaft and a cross universal coupling. Background Art

[0002] The cross universal coupling is used to connect two shafts with intersecting or parallel axes to transmit rotation and torque. It is one of the key components of mechanical transmission and is widely used in mechanical equipment such as metallurgy, lifting, and papermaking. The cross pack is a key and vulnerable component of the cross universal coupling. The cross pack mainly consists of a cross shaft and four combined bearings set on the cross shaft diameter. It has many structural types, mainly divided into SWC type, SWZ type, and SWP type. After a certain period of use, the cross universal coupling is removed from the machine for repair, mainly due to failures such as wear, pitting, and spalling of the cross pack bearings. Therefore, the development direction of this technology field has always been to continuously improve the cross pack structure, increase its load-bearing capacity, extend its service life, shorten the repair cycle, and reduce repair costs.

[0003] The currently used joint cross shaft, equivalent to the inner raceway of a bearing, can develop indentations and spalling defects during use. Conventional repair methods involve regrinding the raceway, reducing its dimensions, and adapting it to the rollers. Due to the limited depth of the raceway hardened layer, the number of times the cross shaft can be repaired is limited, thus shortening the service life of the joint cross shaft.

[0004] To address the aforementioned issues, Chinese patent application CN219013210U has been found to disclose a cross-shaped universal joint coupling comprising a cross shaft and a bearing; the bearing comprising an inner ring, an outer ring, and rolling elements; the inner ring of the bearing having an interference fit with the journal of the cross shaft, and an elastic retaining ring disposed at the outer end of the journal to limit the inner ring of the bearing axially along the journal; a retaining ring having an interference fit on the shoulder of the cross shaft, and a sealing connection between the outer ring of the bearing and the retaining ring. Due to the interference fit between the inner ring of the bearing and the journal of the cross shaft, the rolling elements of the bearing contact the inner ring of the bearing rather than directly contacting the outer surface of the journal, thereby reducing the requirements for the surface hardness, finish, and form and position tolerances of the journal of the cross shaft, requiring only quenching and tempering treatment, thereby simplifying the manufacturing process of the cross shaft and reducing manufacturing costs; and after a period of use, the inner ring of the bearing, the outer ring of the bearing, and the rolling elements of the bearing wear, while the journal of the cross shaft does not wear, and the cross shaft can be directly reused.

[0005] For example, Chinese patent application CN206830683U discloses a cross package of a cross-axis universal joint, which includes a cross shaft and a combined bearing. The combined bearing includes a bearing outer ring and a retaining frame. The retaining frame is arranged at the open end of the bearing outer ring, and a thrust pad is provided between the two. A step structure is provided on the outside of the bearing outer ring, and the step structure is provided with an adjusting washer. The retaining frame is located on the outside of the bearing outer ring and is provided with an oil seal. The oil seal is located between the adjusting washer and the retaining frame and is pressed against the bearing outer ring. The journal section of the cross shaft passes through the retaining frame and extends into the bearing outer ring. The other end of the retaining frame is pressed against the shoulder position of the journal section. The circumferential surface of the journal section is provided with a bearing inner ring. A rolling body is provided between the bearing inner ring and the bearing outer ring. A rolling body limiting structure is also provided. A main lubricating oil channel is provided in the cross shaft.

[0006] However, by analyzing the structure of the above-mentioned patent, it can be found that, especially during use, the seal between the inner ring of the bearing and the shaft neck is not good, which leads to the leakage of lubricating grease. This not only pollutes the factory environment, but also causes the bearing to be poorly lubricated due to lack of oil, ultimately leading to premature aging of the bearing and affecting the service life of the bearing. Summary of the Invention

[0007] 1. Problem to be solved

[0008] In response to the problem in the prior art that poor sealing between the inner ring of the bearing and the shaft neck leads to oil leakage and failure of the bearing, the present invention provides a cross bag with a joint cross shaft, which ensures that the inner ring of the bearing and the shaft neck fit tightly without affecting the normal rotation of the bearing, ensures that there is no oil leakage during use, and ensures that the use of the bearing is not affected.

[0009] Another object of the present invention is to provide a cross universal coupling having the above-mentioned cross package with a joint cross shaft.

[0010] 2. Technical Solution

[0011] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0012] The cross pack with a joint cross shaft of the present invention comprises a cross shaft and a bearing; the cross shaft has four shaft heads, each shaft head is equipped with an end cap, and the end cap is provided with an oiling nozzle for injecting oil into the bearing; the bearing comprises a bearing inner ring, a bearing outer ring and a bearing rolling element; the bearing rolling element is capable of rotating along a raceway formed by the bearing outer ring and the bearing inner ring;

[0013] The bearing inner ring includes an inner ring body, and the inner ring body is interference-fitted with the journal of the cross shaft, so that the bearing outer ring can rotate with the bearing rolling element;

[0014] The inner ring body is cylindrical and extends to both sides along the central axis, respectively converging toward the axis to form a stop ring and expanding toward the axis to form a fitting portion; there is a fitting gap between the inner side surface of the fitting portion and the journal of the cross shaft, and a stop protrusion is formed on the outer circumference thereof, and a rotating sealing strip is provided between the outer ring of the bearing and the stop protrusion, and the rotating sealing strip is matched with a lip sealing ring; the stop ring fits against the end face of the shaft head to limit the inner ring of the bearing in the axial direction.

[0015] In a possible implementation manner of the present invention, an inner retaining ring is provided on the outer circumference of the stop ring, and the inner retaining ring can abut against the bearing rolling element.

[0016] In a possible implementation manner of the present invention, an O-ring is provided between the inner side surface of the fitting portion and the journal of the cross shaft.

[0017] In a possible implementation manner of the present invention, an escape groove for accommodating the stop ring is formed on the inner side surface of the end cover, and the depth of the escape groove is greater than the height of the stop ring.

[0018] In a possible implementation manner of the present invention, an outer retaining ring for axial limitation is provided between the end cover and the outer ring of the bearing, and the outer retaining ring is also equipped with a seal.

[0019] In a possible implementation manner of the present invention, the oiling nozzle is arranged at the center of the end cover.

[0020] In a possible implementation manner of the present invention, the circumferential outer surface of the inner ring body that contacts the bearing rolling elements is parallel to the axis of the shaft head.

[0021] In a possible implementation manner of the present invention, the circumferential outer surface of the inner ring body in contact with the bearing rolling elements has a layer of Ag-graphene composite coating.

[0022] In one possible implementation of the present invention, the thickness of the Ag-graphene composite coating is 3 microns to 5 microns.

[0023] The present invention also provides a cross universal coupling, comprising a fork and a cross package connecting the fork; the cross package is the above-mentioned cross package with a joint cross shaft.

[0024] 3. Beneficial effects

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The cross bag with a joint cross shaft of the present invention has an inner ring body extending to both sides along the central axis, which respectively converges toward the axis to form a stop ring and expands toward the axis to form a fitting portion; there is a fitting gap between the inner side surface of the fitting portion and the shaft neck of the cross shaft, and a stop protrusion is formed on the outer side of its circumference, and a rotating sealing strip is provided between the outer ring of the bearing and the stop protrusion, and the rotating sealing strip is matched with a lip-shaped sealing ring; the stop ring fits with the end face of the shaft head to limit the inner ring of the bearing in the axial direction; without affecting the normal rotation of the bearing, it is ensured that the inner ring of the bearing and the shaft neck are tightly fitted, ensuring that there is no oil leakage during use, and ensuring that the use of the bearing is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, these drawings are intended only to conceptually illustrate the structures described herein and are not necessarily drawn to scale.

[0028] Figure 1 It is a schematic structural diagram of a cross bag with a joint cross shaft of the present invention;

[0029] Figure 2 A schematic structural diagram of a bearing inner ring of the present invention;

[0030] Figure 3 for Figure 1 A magnified view of part A;

[0031] Figure 4 for Figure 1 A magnified view of part B;

[0032] Figure 5 This is another structural schematic diagram of the bearing inner ring of the present invention;

[0033] Figure 6 for Figure 5 Magnified view of part C;

[0034] Figure 7 These are the measurement results of Ag-graphene composite coating.

[0035] Description of reference numerals:

[0036] 10. Cross shaft; 11. Shaft head; 12. End cover; 121. Avoidance groove; 13. Grease nipple; 14. Outer retaining ring;

[0037] 20. Bearing; 21. Bearing inner ring; 211. Inner ring body; 212. Stop ring; 213. Fitting part; 214. Stop protrusion; 215. Rotary sealing strip; 216. Lip seal; 217. Inner stop ring; 218. O-ring; 219. Ag-graphene composite coating; 22. Bearing outer ring; 23. Bearing rolling element. DETAILED DESCRIPTION

[0038] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is merely for illustration and does not limit the description of the features and characteristics of the present invention, so as to propose the best way to perform the present invention and be sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0039] The following detailed description of the present invention and example embodiments may be better understood with reference to the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0040] Example 1

[0041] like Figures 1 to 7 As shown, the cross package with a joint cross shaft in this embodiment includes a cross shaft 10 and a bearing 20. The cross shaft 10 is made of alloy structural steel, and its mechanical properties are as follows: a) δ m ≥1150MPa; b)δ cL ≥900MPa; c)A KU ≥60J; the journal surface of the cross shaft 10 should be carburized, the effective carburized layer depth is 1.3mm-1.8mm, and the surface hardness is 58HRC-62HRC; the journal size tolerance zone should comply with the h6 grade requirements in GB / T1800.4.

[0042] The above-mentioned cross shaft 10 has four shaft heads 11, and the shaft heads 11 are equipped with end covers 12. The above-mentioned end covers 12 are provided with oiling nozzles 13 for injecting oil into the bearings 20. The oiling nozzles 13 can be connected to external oil supply equipment, and the external oil supply equipment includes but is not limited to hydraulic pumps, electric pumps and pneumatic pumps, preferably electric pumps.

[0043] In this embodiment, the oiling nozzle 13 is arranged at the center position of the end cover 12. The above-mentioned oiling nozzles 13 all adopt the oiling nozzles 13 of the existing technology, such as the oiling nozzle 13 disclosed in Chinese patent application CN215807806U, which includes a central shaft and an oiling nozzle 13 arranged on the surface of the central shaft. The oiling nozzle 13 is a hollow cylindrical structure. The oiling nozzle 13 includes an oil inlet and an oil outlet arranged on the central shaft. The inside of the oiling nozzle 13 is provided with an oil sealing body for blocking the oil inlet and a spring provided on the lower surface of the oil sealing body and connected to the upper surface of the central shaft. A plurality of sliding grooves are provided in the axial direction of the inner wall of the oiling nozzle 13, and a slider adapted to the sliding groove is provided on the lower surface of the oil sealing body along the radial direction of the oiling nozzle 13. The upper surface of the slider is provided with an oil scraper ring with an annular structure for scraping contaminants off the inner wall of the oiling nozzle 13.

[0044] In this embodiment, the bearing 20 includes a bearing inner ring 21 , a bearing outer ring 22 and bearing rolling elements 23 ; the bearing rolling elements 23 can rotate along a raceway formed by the bearing outer ring 22 and the bearing inner ring 21 .

[0045] 1. Bearing outer ring

[0046] 1) The material of the bearing outer ring 22 is alloy structural steel, and its mechanical properties are: a) δ m ≥1150MPa; b)δ cL ≥900MPa; c)A KU ≥60J.

[0047] 2) Carburizing treatment of internal and external working surfaces, effective carburizing layer depth is 1.3mm-1.8mm, surface hardness is 58HRC-62HRC;

[0048] 3) The dimensional tolerance zone of the outer working surface of the bearing outer ring 22 shall comply with the h6 grade requirements in GB / T1800.4;

[0049] 4) The inner working surface dimension tolerance of the bearing outer ring 22 shall comply with the requirements of level 6 in GB / T1800.4;

[0050] 5) The cylindricity tolerance of the inner and outer working surfaces of the bearing outer ring 22 shall not be greater than Grade 6 in GB / T1184, and the coaxiality shall not be greater than Grade 6 in GB / T1184;

[0051] 6) The inner and outer surface roughness R of the bearing outer ring 22 shall not exceed 0.4 μm and 0.8 μm respectively;

[0052] 7) After the outer ring 22 of the bearing is processed, it should be subjected to ultrasonic testing, and the quality grade should comply with the requirements of Grade I in JB / T5000.15.

[0053] 2. Bearing rolling elements

[0054] 1) The manufacturing of the bearing rolling element 23 is in accordance with Grade II of GB / T4661.

[0055] 2) Bearing 20 assembly

[0056] A. After assembly, the total circumferential clearance of the bearing rolling elements 23 should generally be between 0.45mm and 0.70mm;

[0057] B. After assembly, the total axial clearance of the bearing rolling elements 23 should generally be between 0.25mm and 0.40mm.

[0058] The bearing inner ring 21 in this embodiment includes an inner ring body 211. This inner ring body 211 has an interference fit with the journal of the cross shaft 10, allowing the bearing outer ring 22 to rotate with the bearing rolling elements 23. The bearing rolling elements 23 can be spherical, cylindrical, or in various other shapes. The number of rolling elements 23 provided is determined based on the specific situation. For example, a long cylindrical rolling element can be arranged around the circumference of the journal segment, or multiple spherical rolling elements can be arranged axially along the journal segment.

[0059] Considering that the cross shaft 10 is used in a universal coupling, connecting two forks and then rotating to transmit torque, the bearing inner ring 21 is set on the shaft head 11. It is necessary not only to ensure the stability of the bearing inner ring 21, but also to ensure the sealing after installation (filled with lubricating grease). Therefore, if Figure 2 、 Figure 3 and Figure 4 As shown, the inner ring body 211 is cylindrical and extends in both directions along the central axis, converging toward the axis to form a stop ring 212 and expanding toward the axis to form a mating portion 213. A clearance exists between the inner side of the mating portion 213 and the journal of the cross shaft 10, and a stop protrusion 214 is formed on the outer circumference of the mating portion 213. A rotating seal strip 215 is provided between the bearing outer ring 22 and the stop protrusion 214. The rotating seal strip 215 is fitted with a lip seal 216. An O-ring 218 is also provided between the inner side of the mating portion 213 and the journal of the cross shaft 10. The rotating seal strip 215, lip seal 216, and O-ring 218 effectively seal and reduce the leakage of lubricating grease.

[0060] like Figure 1 As shown, the stop ring 212 fits tightly against the end face of the shaft head 11 to limit the bearing inner ring 21 in the axial direction; an inner stop ring 217 is provided on the outer circumference of the stop ring 212, and the inner stop ring 217 can abut against the bearing rolling element 23.

[0061] An escape groove 121 for accommodating the stop ring 212 is formed on the inner side surface of the end cover 12 . The depth of the escape groove 121 is greater than the height of the stop ring 212 . The escape groove 121 constitutes a part of the oil supply cavity and can store lubricating grease.

[0062] An outer retaining ring 14 for axial limitation is provided between the end cover 12 and the bearing outer ring 22 , and the outer retaining ring 14 is equipped with a seal to effectively prevent the leakage of lubricating grease.

[0063] In this embodiment, the circumferential outer surface of the inner ring body 211 that contacts the bearing rolling elements 23 is parallel to the axis of the shaft head 11, which is easier to install and fit than the bearing 20 with a tapered surface used in the prior art.

[0064] Furthermore, the bearing rolling element 23 rotates continuously during use, and the surface in contact with the inner ring body 211 is subject to greater wear. Therefore, the circumferential outer surface of the inner ring body 211 can be carburized with reference to the surface of the bearing outer ring 22. The effective carburized layer depth is 1.3mm-1.8mm, and the surface hardness is 58HRC-62HRC.

[0065] A large amount of heat is also generated during the rotation of the bearing rolling elements 23. In the prior art, the bearing rolling elements 23 are in direct contact with the shaft head 11, and the generated heat is directly transferred to the shaft head 11. However, the bearing rolling elements 23 of the present invention are separated from the shaft head 11 by the bearing inner ring 21, which hinders the effective transfer of heat. Therefore, the friction coefficient of the bearing inner ring 21 is reduced as much as possible to enhance the thermal conductivity of the bearing inner ring 21.

[0066] Through a lot of experiments, such as Figure 5 and Figure 6 As shown, a layer of Ag-graphene composite coating 219 is plated on the surface of the inner ring body 211 (using the existing bath electroplating method, such as the carburizing and quenching parts electroplating process used by our company), which has high wear resistance, reduces adhesive wear, and has good thermal conductivity and lubrication effects, and can effectively improve the service life of the inner ring body 211.

[0067] The inner ring body 211 coated with the Ag-graphene composite coating 219 is compared with the inner ring body 211 made of alloy structural steel currently used in the market (such as high manganese alloy steel). Specific data are shown in the following table:

[0068]

[0069] According to the data in the table, the use of the improved pin 10 has been improved, wherein the average wear volume / mm after 6 months of use has been reduced by at least 30%.

[0070] Through cross-sectional observations using FE-SEM (Field Emission Scanning Electron Microscope) and TEM (Transmission Electron Microscope), it was found that an Ag-graphene composite coating 219 was formed on the inner ring body 211, which smoothed the surface, reduced minor rotational deviations, and solved the problem of resonant jitter.

[0071] like Figure 7 As shown in the following measurement, when the thickness of the Ag-graphene composite coating 219 is 1µm, the preferred orientation is <111> direction, while when the thickness of the Ag-graphene composite coating 219 is 3µm, the preferred orientation is <220> Therefore, from the perspective of crystal structure stability, the film thickness range is 3µm-5µm, which can fully improve the strength and thermal conductivity of the coating.

[0072] This embodiment also provides a cross universal coupling, including a fork and a cross bag connecting the fork; the cross bag is processed and applied to the universal coupling, achieving good use effect.

Claims

1. A cross pack with a joint cross shaft, comprising a cross shaft (10) and a bearing (20); the cross shaft (10) has four shaft heads (11), the shaft heads (11) are equipped with end covers (12), and the end covers (12) are provided with an oiling nozzle (13) for injecting oil into the bearing (20); the bearing (20) comprises a bearing inner ring (21), a bearing outer ring (22) and a bearing rolling element (23), and the bearing rolling element (23) can rotate along a raceway formed by the bearing outer ring (22) and the bearing inner ring (21); characterized in that, The bearing inner ring (21) includes an inner ring body (211), and the inner ring body (211) is interference-fitted with the journal of the cross shaft (10), so that the bearing outer ring (22) can rotate along with the bearing rolling element (23); The inner ring body (211) is cylindrical and extends to both sides along the central axis, and is respectively gathered toward the axis to form a stop ring (212) and expanded toward the axis to form a fitting portion (213); there is a fitting gap between the inner side surface of the fitting portion (213) and the journal of the cross shaft (10), and a stop protrusion (214) is formed on the outer circumference thereof, and a rotating sealing strip (215) is provided between the bearing outer ring (22) and the stop protrusion (214), and the rotating sealing strip (215) is matched with a lip sealing ring (216); the stop ring (212) is fitted with the end face of the shaft head (11) to limit the bearing inner ring (21) in the axial direction; An inner retaining ring (217) is provided on the outer circumference of the retaining ring (212), and the inner retaining ring (217) can abut against the bearing rolling element (23).

2. The cross bag with a joint cross shaft according to claim 1, characterized in that: An O-type sealing ring (218) is provided between the inner side surface of the matching portion (213) and the journal of the cross shaft (10).

3. The cross bag with a joint cross shaft according to claim 2, characterized in that: An escape groove (121) for accommodating the stop ring (212) is formed on the inner side surface of the end cover (12), and the depth of the escape groove (121) is greater than the height of the stop ring (212).

4. The cross bag with a joint cross shaft according to claim 3, characterized in that: An axially limited outer retaining ring (14) is provided between the end cover (12) and the bearing outer ring (22), and the outer retaining ring (14) is also equipped with a seal.

5. The cross bag with a joint cross shaft according to any one of claims 1 to 4, characterized in that: The oiling nozzle (13) is arranged at the center of the end cover (12).

6. The cross bag with a joint cross shaft according to claim 5, characterized in that: The circumferential outer surface of the inner ring body (211) in contact with the bearing rolling element (23) is parallel to the axis of the shaft head (11).

7. The cross bag with a joint cross shaft according to claim 6, characterized in that: The circumferential outer surface of the inner ring body (211) in contact with the bearing rolling element (23) has a layer of Ag-graphene composite coating (219).

8. The cross bag with a joint cross shaft according to claim 7, characterized in that: The thickness of the Ag-graphene composite coating (219) is 3 micrometers to 5 micrometers.

9. A cross universal coupling, comprising a fork and a cross bag connecting the fork; characterized in that: The cross bag is a cross bag with a joint cross shaft as described in any one of claims 1 to 8.

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