High speed transmission oil floating slewing bearing

Abstract

The application provides a high-speed transmission oil floating rotary support, an oil inlet hole is arranged in an inner ring, a radial inward protruding part on an outer ring covers an oil outlet hole of the oil inlet hole, an annular groove is arranged on the inner ring, the oil outlet hole is located between the two annular grooves, and three annular grooves on the outer ring form a male-female gap fit with the two annular grooves on the inner ring; high-pressure hydraulic oil enters from the oil inlet hole of the inner ring, comes out from an upper end face, and directly acts in the annular groove of the outer ring; the outer ring is subjected to an upward force and floats upward; when the rotary support bears a static pressure load, the hydraulic oil pump pressure can be adjusted; a whole copper retainer is used to replace a single nylon isolation block, and the rolling of the ball is controllable; the oil floating structure offsets most of the axial force of the ball, reduces the wear of the ball, improves the service life from the structure, improves the manufacturing precision from the manufacturing process, realizes the accuracy of movement, and realizes the application in high-speed rotary transmission machinery.

Description

Technical Field

[0001] This invention belongs to the field of slewing bearing technology, specifically relating to a high-speed transmission oil-floating slewing bearing. Background Technology

[0002] Slewing bearings can withstand not only large axial loads but also significant overturning moments, and are widely used in low-speed rotating construction machinery such as excavators, tower cranes, hoists, and port lifting machinery. Slewing bearings integrate the rotation of the bearing with the transmission of gears, combining the original bearing, bearing housing, spindle, and gears into one unit, greatly simplifying and optimizing design and manufacturing. They are now widely used in low-speed rotating construction machinery, welding machinery, filling machinery, and grinding machinery.

[0003] However, existing slewing bearings (taking a raceway center diameter of 1000mm as an example) can only be used on equipment with low-speed rotation (design speed of 3rpm) and are not suitable for high-speed rotation (50rpm). The reasons are as follows: (1) The rolling steel balls wear out under a large axial load; (2) The movement of the rolling steel balls in the raceway involves not only rolling but also sliding, resulting in additional impact. Nylon isolation blocks are used to buffer the steel balls, and these blocks are easily broken under additional impact; (3) Existing slewing bearings have low manufacturing precision. The raceway is machined by turning and not ground, resulting in large axial and radial clearances, large runout, and large vibration during high-speed transmission; (4) The gear teeth are not ground after heat treatment, resulting in large pitch circle runout, which cannot achieve precise and smooth transmission. During high-speed rotation, there is a large additional impact force. Summary of the Invention

[0004] The purpose of this invention is to provide a high-speed transmission oil-floating slewing bearing to enable the application of slewing bearings (taking a raceway center diameter of 1000mm as an example) in high-speed rotary (50rpm) transmission mechanical equipment, such as vertical lathes.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0006] A high-speed transmission oil-floating slewing bearing includes an inner ring, an outer ring, and rolling balls. The inner ring is provided with at least two hydraulic oil inlet channels for hydraulic oil flow. The inlet holes of the hydraulic oil inlet channels are opened on the inner diameter surface of the inner ring, and the outlet holes of the hydraulic oil inlet channels are opened on the upper end surface of the inner ring.

[0007] The outer ring is provided with a radially inward protrusion. The lower surface of the radially inward protrusion covers the oil outlet of the hydraulic oil inlet channel on the inner ring. A gap is left between the lower surface of the radially inward protrusion and the upper end face of the inner ring.

[0008] Two annular grooves are provided on the upper end face of the inner ring, and the oil outlet of the hydraulic oil inlet channel is located between the two annular grooves on the inner ring.

[0009] Three annular grooves are provided on the lower surface of the radially inward protrusion, and the three annular grooves on the outer ring and the two annular grooves on the inner ring form a male-female clearance fit.

[0010] Preferably, all hydraulic oil inlet channels are evenly distributed circumferentially on the inner ring;

[0011] The hydraulic oil inlet channel consists of horizontal holes and vertical holes, which are connected to form the channel.

[0012] Preferably, the high-speed transmission oil-floating slewing bearing further includes a copper cage and a cage retaining ring. The ball is embedded in a hole in the copper cage, and the cage retaining ring is used to support the copper cage and prevent the copper cage from coming out. The cage retaining ring is installed at the corner between the inner diameter surface and the lower end face of the outer ring.

[0013] This application provides a high-speed transmission oil-floating slewing bearing, wherein the inner ring is provided with at least two hydraulic oil inlet channels for hydraulic oil flow, the inlet holes of the hydraulic oil inlet channels are opened on the inner diameter surface of the inner ring, and the outlet holes of the hydraulic oil inlet channels are opened on the upper end surface of the inner ring.

[0014] The outer ring is provided with a radially inward protrusion. The lower surface of the radially inward protrusion covers the oil outlet of the hydraulic oil inlet channel on the inner ring. A gap is left between the lower surface of the radially inward protrusion and the upper end face of the inner ring.

[0015] Two annular grooves are provided on the upper end face of the inner ring, and the oil outlet of the hydraulic oil inlet channel is located between the two annular grooves on the inner ring.

[0016] Three annular grooves are provided on the lower surface of the radially inward protrusion, and the three annular grooves on the outer ring and the two annular grooves on the inner ring form a male-female clearance fit.

[0017] This application provides a method for preparing a high-speed transmission oil-floating slewing bearing, including ring rolling, machining, quenching and tempering, grinding, and finished product assembly. By optimizing the process steps and parameters, the hardness of the raceway after quenching and tempering is 58-62 HRC, the thickness of the hardened layer of the raceway is not less than 5 mm, the hardness of the tooth surface and tooth root after quenching and tempering is 50-60 HRC, the thickness of the hardened layer of the tooth surface is not less than 3.2 mm, the thickness of the hardened layer of the tooth root is not less than 1.2 mm, the axial and radial clearances between the inner and outer raceways are ≤0.02 mm, the axial and radial runouts are ≤0.02 mm, and the radial runout of the tooth pitch circle relative to the raceway is ≤0.03 mm.

[0018] This application adopts an oil float structure, which offsets most of the axial force borne by the ball, reduces the wear of the ball, and improves its service life. In the oil float structure, high-pressure hydraulic oil enters from the oil inlet of the inner ring and comes out from the upper end face, directly acting on the oil groove of the outer ring. The hydraulic oil flows out from the wave groove, and the outer ring floats up due to the upward force. When the slewing bearing is subjected to static pressure load, the pressure of the high-pressure hydraulic oil pump is adjusted to ensure that the starting torque of the slewing bearing is not greater than 30 N·m.

[0019] This application uses an integral copper cage instead of a single nylon spacer, achieving controllable ball rolling;

[0020] This application improves the service life of slewing bearings structurally, meeting the requirements of high-speed rotation, and improves the manufacturing precision of slewing bearings in terms of manufacturing process, achieving precise motion, thereby realizing the application of slewing bearings in high-speed rotary transmission machinery. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a horizontally mounted high-speed transmission oil-floating slewing bearing provided in an embodiment of this application.

[0022] Figure 2 for Figure 1 Enlarged view of area A where the oil float structure is located (enlarged view showing the hydraulic oil inlet channel, oil inlet hole, oil outlet hole, and three annular grooves forming a male-female clearance fit with two annular grooves in the oil float structure).

[0023] In the diagram: 1 Outer ring (toothed), 2 Ball, 3 Inner ring (toothless), 4 Mounting hole (threaded or smooth), 5 Brass cage, 6 Cage retaining ring, 7 Hydraulic oil inlet hole, 8 Return oil channel;

[0024] 9. Fixed base, 10. Turntable. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1-2 In the middle: outer ring 1 (toothed), ball 2, inner ring 3 (toothless), mounting hole (threaded hole or smooth hole) 4, copper cage 5, cage retaining ring 6, hydraulic oil inlet hole 7, return oil channel 8; fixed base 9, turntable 10.

[0027] This application provides a high-speed transmission oil-floating slewing bearing, including an inner ring 3, an outer ring 1, and a ball 2. The inner ring 3 is provided with at least two hydraulic oil inlet channels for hydraulic oil flow. The inlet holes of the hydraulic oil inlet channels are opened on the inner diameter surface of the inner ring 3, and the outlet holes of the hydraulic oil inlet channels are opened on the upper end surface of the inner ring 3.

[0028] The outer ring 1 is provided with a radially inward protrusion. The lower surface of the radially inward protrusion covers the oil outlet of the hydraulic oil inlet channel on the inner ring 3. A gap is left between the lower surface of the radially inward protrusion and the upper end face of the inner ring 3.

[0029] Two annular grooves are provided on the upper end face of the inner ring 3, and the oil outlet of the hydraulic oil inlet channel is located between the two annular grooves on the inner ring 3.

[0030] Three annular grooves are provided on the lower surface of the radially inward protrusion, and the three annular grooves on the outer ring 1 and the two annular grooves on the inner ring 3 form a male-female clearance fit.

[0031] In one embodiment of this application, all the hydraulic oil inlet channels are evenly distributed circumferentially on the inner ring 3.

[0032] The hydraulic oil inlet channel consists of horizontal holes and vertical holes, which are connected to form the channel.

[0033] In one embodiment of this application, the high-speed transmission oil-floating slewing bearing further includes a copper cage 5 and a cage retaining ring 6. The ball 2 is embedded in a hole in the copper cage 5. The cage retaining ring 6 is used to support the copper cage 5 and prevent the copper cage 5 from coming out. The cage retaining ring 6 is installed at the corner between the inner diameter surface and the lower end face of the outer ring 1.

[0034] The method for manufacturing a high-speed transmission oil-floating slewing bearing provided in this application includes the following steps performed sequentially:

[0035] 1) The outer ring blank is obtained by rolling a 42CrMo steel forging.

[0036] The inner ring blank is made by rolling a 42CrMo steel forging.

[0037] 2) The outer ring blank obtained in step 1) is machined to obtain the outer ring semi-finished product;

[0038] The inner ring blank obtained in step 1) is machined to obtain the inner ring semi-finished product.

[0039] 3) Both the outer ring semi-finished product and the inner ring semi-finished product are first subjected to quenching and tempering treatment. The hardness of the raceway after quenching and tempering treatment is controlled to be 58-62HRC, and the thickness of the quenched hardened layer of the raceway is not less than 5mm.

[0040] The hardness of the tooth surface and tooth root after tempering is controlled to be 50-60 HRC, the thickness of the hardened layer on the tooth surface is not less than 3.2 mm, and the thickness of the hardened layer on the tooth root is not less than 1.2 mm.

[0041] 4) Grinding process: The raceways of the inner ring 3, the raceways of the outer ring 1, the mounting end face and the gear teeth are first rough ground, then stress-relief annealing is performed, and then fine grinding is performed to control the axial and radial clearances between the inner and outer ring raceways to be ≤0.02mm, the axial and radial runouts to be ≤0.02mm, and the radial runout of the gear tooth pitch circle relative to the raceway to be ≤0.03mm;

[0042] 5) Finished product assembly: Assemble the inner ring 3, outer ring 1 and ball 2 together to form the finished slewing bearing.

[0043] In this application, the return oil channel 8 is provided in the fixed base 9. The return oil channel 8 is used to collect and discharge the hydraulic oil flowing out from the oil float structure, recover the hydraulic oil and discharge it from the slewing bearing, and then send it to the oil storage tank of the hydraulic oil pump station.

[0044] This application provides a high-speed transmission oil-floating slewing bearing that achieves the working principle of high-speed rotation:

[0045] (1) The use of an oil-floating structure in the structural design greatly reduces the wear of the rolling steel balls;

[0046] Oil float structure: There are two annular grooves on the upper end face of the inner ring 3, and six oil outlet holes are evenly distributed between the two annular grooves. There are three annular grooves on the outer ring 1, which form a male-female clearance fit with the two annular grooves of the inner ring 3.

[0047] The inner ring has 6 hydraulic oil inlet channels inside, 6 oil inlet holes on the inner diameter surface of the inner ring, and 2 annular grooves on the upper end face of the inner ring, with 6 evenly distributed oil outlet holes between the 2 annular grooves.

[0048] The outer ring has a flange step (radially inward protrusion) in the inner diameter direction, and three annular grooves are provided on the lower surface of the flange step.

[0049] High-pressure hydraulic oil enters from the oil inlet 7 on the inner ring 3 and exits from the oil outlet on the upper end face of the inner ring 3. It acts directly on the surface of the annular groove in the middle of the outer ring and then flows out through the gap between the annular groove between the inner ring 3 and the outer ring 1. The outer ring 1 floats up due to the outward force of the high-pressure hydraulic oil. When the slewing bearing is subjected to static pressure load, the pump pressure of the high-pressure hydraulic oil is adjusted to ensure that the starting torque of the slewing bearing is not greater than 30 N·m.

[0050] (2) The integral copper cage 5 is used to replace the individual nylon isolation block to achieve controllable rolling of the steel ball;

[0051] The copper cage 5 is an integral type, and the copper cage 5 rotates together with the outer ring 1;

[0052] The steel ball is placed in the hole of the copper cage. When the slewing bearing moves, the steel ball not only rotates on its own axis, but also revolves with the copper cage.

[0053] (3) Grind the raceway of the slewing bearing to achieve precise and smooth transmission;

[0054] The raceways of inner ring 3 and outer ring 1 are ground. The raceways of inner ring 3 and outer ring 1 are heat treated and then ground to ensure that the axial clearance and radial clearance of the inner ring raceway and the outer ring raceway are ≤0.02mm and the axial runout and radial runout are ≤0.02mm.

[0055] (4) Grind the teeth on the outer ring to improve the precision grade of the teeth and eliminate the impact during high-speed transmission;

[0056] After heat treatment, the gear teeth are ground to achieve a precision of grade 7, while ensuring that the radial runout of the gear tooth pitch circle relative to the raceway is ≤0.03mm.

[0057] In this application, quenching and tempering refers to a dual heat treatment method of quenching followed by high-temperature tempering, the purpose of which is to give the workpiece good comprehensive mechanical properties. High-temperature tempering refers to tempering between 500-650℃. Quenching and tempering can greatly adjust the properties and material of steel, resulting in better strength, plasticity, and toughness, and thus good comprehensive mechanical properties. After quenching and tempering, tempered sorbite is obtained, which is formed from martensite during tempering.

[0058] In this application, the term "inner" is the same as "inner" in the inner circle, and the term "outer" is the same as "outer" in the outer circle.

[0059] The methods and apparatus not described in detail in this invention are all prior art and will not be elaborated further.

[0060] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A high-speed transmission oil-floating slewing bearing, comprising an inner ring, an outer ring, and ball bearings, characterized in that, The inner ring is provided with at least two hydraulic oil inlet channels for hydraulic oil flow. The inlet holes of the hydraulic oil inlet channels are opened on the inner diameter surface of the inner ring, and the outlet holes of the hydraulic oil inlet channels are opened on the upper end surface of the inner ring. The outer ring is provided with a radially inward protrusion. The lower surface of the radially inward protrusion covers the oil outlet of the hydraulic oil inlet channel on the inner ring. A gap is left between the lower surface of the radially inward protrusion and the upper end face of the inner ring. Two annular grooves are provided on the upper end face of the inner ring, and the oil outlet of the hydraulic oil inlet channel is located between the two annular grooves on the inner ring. Three annular grooves are provided on the lower surface of the radially inward protrusion, and the three annular grooves on the outer ring and the two annular grooves on the inner ring form a male-female clearance fit.

2. The high-speed transmission oil-floating slewing bearing according to claim 1, characterized in that, All hydraulic oil inlet channels are evenly distributed circumferentially on the inner ring. The hydraulic oil inlet channel consists of horizontal holes and vertical holes, which are connected to form the channel.

3. A high-speed transmission oil-floating slewing bearing according to claim 1, characterized in that, The high-speed transmission oil-floating slewing bearing also includes a copper cage and a cage retaining ring. The ball is embedded in a hole in the copper cage, and the cage retaining ring is used to support the copper cage and prevent the copper cage from coming out. The cage retaining ring is installed at the corner between the inner diameter surface and the lower end face of the outer ring.

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