Back-to-back double-row self-aligning roller bearing and assembling method thereof

Abstract

The invention relates to a back-to-back double-row self-aligning roller bearing and an assembly method thereof, the bearing comprises an outer ring, a double-row retainer, a rolling body and an inner ring, the outer ring is provided with two outer ring raceways, the rolling body is a self-aligning roller, and raceway surfaces of the two outer ring raceways are inclined towards the outer diameter surface of the outer ring from the middle part of the outer ring to the end part of the outer ring in the axial direction; the double-row retainer is provided with two rows of retainer beams, the retainer beams are obliquely arranged relative to the central axis of the retainer, and the inclination direction and the inclination degree are matched with the raceway surface of the outer ring raceway; the inner ring comprises two half inner rings, arc-shaped raceways are arranged on the outer diameter surfaces of the half inner rings, the two half inner rings are assembled in a small end face fitting mode, and the arc-shaped raceways of the two half inner rings form a spherical inner ring raceway; the bearing can bear large overturning moment, the shafting rigidity is high, the calorific value is small, the bearing can select a smaller installation clearance or a higher working rotating speed under the same working condition, and the unbalance loading phenomenon during bearing operation is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of bearing structure design, and in particular relates to a back-to-back double-row spherical roller bearing and an assembly method thereof. Background Art

[0002] At present, the double-row spherical roller bearing structure is designed as a face-to-face assembly, that is, the double-row assembly is such that the load action lines L1 and L2 converge toward the bearing center O to form a cross X-shaped arrangement, such as Figure 1 As shown, the load action lines L1 and L2 on both sides intersect with the bearing center line L3, and the load action lines form an angle α with the bearing diameter passing through the intersection point (load action center).

[0003] The advantage of face-to-face assembly is that it can tolerate a certain misalignment error of the shaft system, but the spherical bearing has a stronger ability to tolerate misalignment. This advantage is difficult to be reflected in the spherical bearing. At this time, the disadvantages of face-to-face assembly have greatly affected the performance of the shaft system. The specific disadvantages are as follows: (1) Since the load action lines on both sides converge toward the center of the bearing, the span between the intersections with the bearing centerline L3 is small (the span is 0 when intersecting at the bearing center O), and the cantilever length is large. Therefore, the shaft system has poor ability to withstand overturning moments and weak rigidity; (2) When used, face-to-face bearings are easily heated, causing the internal clearance of the bearing to decrease, which in turn causes the bearing to heat up more; (3) In order to prevent the heating phenomenon of face-to-face bearings, the bearing installation clearance will be selected to be larger, and a large installation clearance may aggravate the unbalanced load phenomenon and lead to reduced shaft system stiffness. Summary of the invention

[0004] The purpose of the present invention is to provide a back-to-back double-row spherical roller bearing and an assembly method thereof. The structural bearing can withstand a large overturning moment, has a high shaft system stiffness, and generates less heat for the bearing. Bearings under the same working conditions can select a smaller installation clearance or a higher operating speed, and the phenomenon of unbalanced load during bearing operation is greatly reduced.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a back-to-back double-row spherical roller bearing, comprising an outer ring, a double-row cage, rolling elements and an inner ring, the inner diameter surface of the outer ring is provided with two outer ring raceways for mounting the double-row rolling elements, the double-row rolling elements are mounted on both sides of the double-row cage, the rolling elements are spherical rollers, the raceway surfaces of the two outer ring raceways are inclined in the axial direction from the middle of the outer ring to the end of the outer ring toward the outer diameter surface of the outer ring, so that the raceway surface normals of the two outer ring raceways are axially away from the center of the bearing; The double-row cage has two rows of cage beams for mounting rolling bodies, and the cage beams are arranged obliquely relative to the central axis of the cage, and the inclination direction and degree are adapted to the raceway surface of the outer ring raceway; The inner ring includes two symmetrical half inner rings, the outer diameter surface of the half inner ring is provided with an arc-shaped raceway, the two axial ends of the half inner ring are respectively a large end face and a small end face, the two half inner rings are assembled together in the form of face-to-face bonding of the small end faces, and the arc-shaped raceways of the two half inner rings form a spherical inner ring raceway.

[0006] An outer middle retaining ring is also arranged between the two outer ring raceways of the outer ring, and the outer middle retaining ring and the outer ring are separate structures.

[0007] A circumferential oil groove is arranged on the outer diameter surface of the outer ring, and a plurality of radial oil holes are distributed along the circumference in the circumferential oil groove. The radial oil holes are connected with the retaining ring oil holes on the outer middle retaining ring. The retaining ring oil holes extend radially and penetrate the inner and outer diameter surfaces of the outer middle retaining ring.

[0008] A small outer ring rib protruding from the outer ring raceway is respectively arranged at two axial ends of the outer ring.

[0009] The outer ring small rib is provided with a notch for installing the rolling body.

[0010] A bearing assembly method, used for assembling the above-mentioned back-to-back double-row spherical roller bearing, comprises the following steps: The first step is to assemble the outer middle retaining ring, a plurality of rolling elements, a retaining frame and an outer ring into an outer ring assembly; The second step is to install the two semi-inner rings into the outer ring assembly from both ends of the outer ring assembly with their small end faces facing each other, and axially press the two semi-inner rings so that their small end faces are closely fitted and contacted; The third step is to keep the two half inner rings axially pressed, fix the gauge for clearance measurement on one side of the outer ring, and make the gauge tip contact the outer diameter surface of the outer ring. Then, apply radial pressure to the outer ring on one side of the gauge, and measure the relative displacement between the half inner ring and the outer ring assembly under the radial pressure. Then, keep the gauge position unchanged, apply radial pressure to the outer ring on the opposite side of the gauge, and measure the relative displacement between the half inner ring and the outer ring assembly under the radial pressure. The difference between the two relative displacements is the measured radial clearance of the bearing. G r测 ; If measuring radial clearance G r测 Meet the design clearance G r设 Required, the assembly is complete.

[0011] In the first step, when installing the outer center retaining ring, the outer center retaining ring is placed into the outer ring at an angle and then aligned.

[0012] In the second step, the two half inner rings are pressed from the large end faces of the half inner rings using an annular pressure plate so that their small end faces fit tightly.

[0013] In the third step, the annular pressure plate is used to press on the large end surface of the half inner ring, and then axial pressure is applied to the annular pressure plate to axially compress the two half inner rings.

[0014] In the third step, if G r测 Greater than G r设 , by grinding the small end face of the half inner ring or replacing the rolling element with a larger gauge to meet the design clearance requirements, complete the assembly; if G r测 Less than G r设 , by replacing the rolling elements with smaller gauge or by exchanging the half inner ring or outer ring of different sizes to meet the design clearance requirements and complete the assembly.

[0015] The principle of the present invention is: when the present invention adopts back-to-back installation, the center line of the load is diffused to both ends of the bearing respectively, so the span between the intersection points with the center line of the bearing is larger than that when the prior art is face-to-face installed, and thus the cantilever length is smaller, so the rigidity of the bearing is greater; when the shaft is heated and elongated, the bearing clearance increases, and the bearing will not get stuck, so the working clearance that can be used can be relatively small or the speed can be relatively high.

[0016] Therefore, the beneficial effects of the present invention are as follows: compared with the face-to-face assembled double-row spherical roller bearing structure in the prior art, the back-to-back double-row spherical roller bearing of the present invention can withstand a larger overturning moment, has a higher shaft system stiffness, and generates less heat for the bearing. Bearings under the same working conditions can choose a smaller installation clearance or a higher operating speed, and the phenomenon of unbalanced load during bearing operation is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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 work.

[0018] Figure 1 It is a structural schematic diagram of a double-row spherical roller bearing assembled face to face in the prior art; Figure 2 It is a structural schematic diagram of the back-to-back double-row spherical roller bearing of the present invention; Figure 3 It is a schematic structural diagram of the cage of the back-to-back double-row spherical roller bearing of the present invention; Figure 4 This is a schematic diagram of the structure of the outer ring assembly during the assembly process of the present invention; Figure 5 It is a schematic diagram of assembling the half inner ring during the assembly process of the present invention; Figure 6 It is a schematic diagram of applying radial pressure at the metering position to measure radial clearance during the assembly process of the present invention; Figure 7 It is a schematic diagram of measuring radial clearance by applying radial pressure in opposite directions at the metering position during the assembly process of the present invention; Markings in the figure: 1. Outer ring, 101. Outer ring raceway, 102. Outer ring small rib, 103. Circumferential oil groove, 104. Radial oil hole, 2. Double row cage, 201. Cage beam, 3. Rolling element, 4. Inner middle retaining ring, 5. Inner ring, 6. Outer middle retaining ring, 601. Retaining ring oil hole, 7. Half inner ring, 701. Inner ring raceway, 702. Large end face, 703. Small end face, 8. Annular pressure plate. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the invention in any way.

[0020] Example 1: Figure 2 As shown, a back-to-back double-row spherical roller bearing comprises an outer ring 1 with double-row raceways, a double-row retaining frame 2, rolling elements 3, a half inner ring 7 and an outer middle retaining ring 6.

[0021] The inner diameter surface of the outer ring 1 is provided with two outer ring raceways 101 for mounting double-row rolling elements 3. The raceway surfaces of the two outer ring raceways 101 are inclined from the middle of the outer ring 1 to the end of the outer ring 1 to the outer diameter surface of the outer ring 1 in the axial direction, so that the raceway surface normals of the two outer ring raceways 101 are axially away from each other toward the two ends of the bearing, forming an O-shaped layout in which the load action lines (L1, L2) diverge toward the two ends of the bearing, and the span of the intersection position of the load action lines (L1, L2) and the bearing center line L3 is relatively large, as shown in detail. Figure 2 As shown. An outer ring small rib 102 protruding from the outer ring raceway 101 is provided at each of the two axial ends of the outer ring 1, and an outer middle rib 6 is provided between the two outer ring raceways 101. The outer middle rib 6 and the outer ring 1 are designed in a split type, and the outer middle rib 6 constitutes a large rib of the outer ring raceway 101. A plurality of rib oil holes 601 are provided at intervals along the circumferential direction on the outer middle rib 6, and the rib oil holes 601 extend radially and penetrate the inner and outer diameter surfaces of the outer middle rib 6. A circumferential oil groove 103 is provided on the outer diameter surface of the outer ring 1, and a plurality of radial oil holes 104 are provided at intervals along the circumferential direction in the circumferential oil groove 103. The outer ends of the radial oil holes 104 open to the circumferential oil groove 103, and the inner end openings are aligned and connected with the rib oil holes 601 on the outer middle rib 6.

[0022] The outer ring small rib is provided with a notch for installing the rolling body.

[0023] like Figure 3 As shown, the double-row cage 2 has two rows of cage beams 201 for mounting rolling elements 3. The cage beams 201 are tilted relative to the central axis of the cage, and the tilt direction and degree are adapted to the outer ring raceway 101. The rolling elements 3 are spherical rollers, which are mounted between adjacent cage beams 201 of the double-row cage 2.

[0024] The inner ring of the bearing in the present invention is composed of two left-right symmetrical half inner rings 7, the outer diameter surface of the half inner ring 7 is an arc surface, and after the two half inner rings 7 are assembled end to end, the inner ring raceway 701 formed by the two arc surfaces is spherical. Since the outer diameter surface is arc-shaped and the inner diameter surface is cylindrical, one end of the half inner ring 7 in the axial direction is the large end surface 702, and the other end is the small end surface 703. When the two half inner rings 7 are assembled, the two small end surfaces 703 are in contact and pressed. The fitting surface after the small end surfaces 703 of the two half inner rings 7 are fitted is a plane S centered in the axial direction of the bearing, and the bearing center O is located on the plane S. The load action lines (L1, L2) form a plane S with the plane S. Figure 2 The angle β is shown.

[0025] Embodiment 2: A method for assembling back-to-back double-row spherical roller bearings, comprising the following steps: The first step, such as Figure 4 As shown, the outer middle retaining ring 6, a plurality of rolling elements 3, a retaining frame 2 and an outer ring 1 are assembled into an outer ring assembly; The second step is, Figure 5 As shown, the two semi-inner rings 7 are installed into the outer ring assembly from both ends of the outer ring assembly with the small end faces 703 facing inward, and the two semi-inner rings 7 are axially pressed so that the small end faces 703 thereof are closely fitted and contacted; The third step is to measure the radial clearance of the bearing by the press-in method, keep the small end faces 703 of the two half inner rings 7 in close contact, use annular pressure plates 8 to press on the large end faces of the half inner rings 7 at both ends of the bearing, and then apply axial pressure to the annular pressure plates 8 to keep the half inner rings 7 pressed axially; then fix the measuring gauge for clearance measurement on the measuring platform, the tip of the measuring gauge contacts the outer diameter surface of the outer ring 1 of the bearing, and the measuring point A is close to the middle position of the outer diameter surface of the outer ring 1, and a certain radial pressure f1 is applied to the outer ring of the bearing on both sides of the measuring point A to measure the relative displacement of the half inner ring 7 and the outer ring assembly under the radial pressure, such as Figure 6 As shown; then, Figure 7 As shown in the figure, keep the measuring gauge in place, apply a radial pressure f2 in another direction on the opposite side of the measuring point A, and measure the relative displacement of the inner ring 7 and the outer ring assembly under the radial pressure; the difference between the two measured relative displacements is the measured radial clearance of the bearing. G r测 .

[0026] If the bearing radial clearance is measured G r测 Meet the design clearance G r设 Required, the assembly is complete; if G r测 Greater than G r设 , the design clearance requirement can be met by grinding the small end face of the half inner ring 7 or replacing the rolling element 3 with a larger gauge, and the assembly can be completed; G r测 Less than G r设 The assembly can be completed by replacing the rolling element 3 with a smaller gauge or by exchanging the half inner ring 7 or the outer ring 1 with different sizes to meet the design clearance requirements.

[0027] In the above assembly method, when installing the outer center retaining ring 6 in the first step, the outer center retaining ring 6 is tilted and placed into the outer ring 1 and then straightened. Since the outer center retaining ring 6 and the outer ring 1 are designed as split parts, the outer center retaining ring 6 can float relative to the outer ring 1. Such a split floating design can better adjust the axial load distribution of the back-to-back double-row spherical roller bearing.

[0028] In the second step, the annular pressure plate 8 can be used to press the two semi-inner rings 7 so that their small end faces 703 fit tightly.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Those skilled in the art should understand that the specific implementation modes of the present invention may be modified or replaced by equivalents with reference to the above embodiments. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the pending claims.

Claims

1. A back-to-back double-row spherical roller bearing, comprising an outer ring, a double-row cage, rolling elements and an inner ring, wherein the inner diameter surface of the outer ring is provided with two outer ring raceways for mounting the double-row rolling elements, the double-row rolling elements are mounted on both sides of the double-row cage, the rolling elements are spherical rollers, and characterized in that: The raceway surfaces of the two outer ring raceways are inclined in the axial direction from the middle of the outer ring to the end of the outer ring toward the outer diameter surface of the outer ring, so that the normal lines of the raceway surfaces of the two outer ring raceways are axially away from the center of the bearing; The double-row cage has two rows of cage beams for mounting rolling bodies, and the cage beams are arranged obliquely relative to the central axis of the cage, and the inclination direction and degree are adapted to the raceway surface of the outer ring raceway; The inner ring includes two symmetrical half inner rings, the outer diameter surface of the half inner ring is provided with an arc-shaped raceway, the two axial ends of the half inner ring are respectively a large end face and a small end face, the two half inner rings are assembled together in the form of face-to-face bonding of the small end faces, and the arc-shaped raceways of the two half inner rings form a spherical inner ring raceway.

2. The back-to-back double-row spherical roller bearing according to claim 1, characterized in that: An outer middle retaining ring is also arranged between the two outer ring raceways of the outer ring, and the outer middle retaining ring and the outer ring are separate structures.

3. The back-to-back double-row spherical roller bearing according to claim 2, characterized in that: A circumferential oil groove is arranged on the outer diameter surface of the outer ring, and a plurality of radial oil holes are distributed along the circumference in the circumferential oil groove. The radial oil holes are connected with the retaining ring oil holes on the outer middle retaining ring. The retaining ring oil holes extend radially and penetrate the inner and outer diameter surfaces of the outer middle retaining ring.

4. The back-to-back double-row spherical roller bearing according to claim 2, characterized in that: A small outer ring rib protruding from the outer ring raceway is respectively arranged at two axial ends of the outer ring.

5. The back-to-back double-row spherical roller bearing according to claim 4, characterized in that: The outer ring small rib is provided with a notch for installing the rolling body.

6. A bearing assembly method for assembling the back-to-back double-row spherical roller bearings according to any one of claims 2 to 5, characterized in that: The steps include: The first step is to assemble the outer middle retaining ring, a plurality of rolling elements, a retaining frame and an outer ring into an outer ring assembly; The second step is to install the two semi-inner rings into the outer ring assembly from both ends of the outer ring assembly with their small end faces facing each other, and axially press the two semi-inner rings so that their small end faces are closely fitted and contacted; The third step is to keep the two half inner rings axially pressed, fix the gauge for clearance measurement on one side of the outer ring, and make the gauge tip contact the outer diameter surface of the outer ring. Then, apply radial pressure to the outer ring on one side of the gauge, and measure the relative displacement between the half inner ring and the outer ring assembly under the radial pressure. Then, keep the gauge position unchanged, apply radial pressure to the outer ring on the opposite side of the gauge, and measure the relative displacement between the half inner ring and the outer ring assembly under the radial pressure. The difference between the two relative displacements is the measured radial clearance of the bearing. G r测 ; If measuring radial clearance G r测 Meet the design clearance G r设 Required, the assembly is complete.

7. The bearing assembly method according to claim 6, characterized in that: In the first step, when installing the outer center retaining ring, the outer center retaining ring is placed into the outer ring at an angle and then aligned.

8. The bearing assembly method according to claim 6, characterized in that: In the second step, the two half inner rings are pressed from the large end faces of the half inner rings using an annular pressure plate so that their small end faces fit tightly.

9. The bearing assembly method according to claim 6, characterized in that: In the third step, the annular pressure plate is used to press on the large end surface of the half inner ring, and then axial pressure is applied to the annular pressure plate to axially compress the two half inner rings.

10. The bearing assembly method according to claim 6, characterized in that: In the third step, if G r测 Greater than G r设 , by grinding the small end face of the half inner ring or replacing the rolling element with a larger gauge to meet the design clearance requirements, complete the assembly; if G r测 Less than G r设 , by replacing the rolling elements with smaller gauge or by exchanging the half inner ring or outer ring of different sizes to meet the design clearance requirements and complete the assembly.

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