Deep groove ball bearing

Abstract

A deep groove ball bearing (10) has an outer ring (11), an inner ring (12), a plurality of balls (13), and a seal member (15). An axial sectional width (W) is smaller than a radial sectional height (H) (W < H), a wall thickness (c) of the inner ring (12) is larger than a wall thickness (d) of the outer ring (11) (c > d), and a pitch circle diameter (PCD) of the balls (13) is larger than a middle diameter (MD) between an inner diameter of the inner ring (12) and an outer diameter of the outer ring (11) (PCD > MD). In addition, a radial dimension (b) between the outer diameter of a shoulder portion (12g) of the inner ring (12) and the inner diameter of the seal member (15) is larger than the wall thickness (d) of the outer ring (11) (b > d). Thus, narrow width and light weight can be achieved, load capacity can be ensured, and lubricating grease leakage can be suppressed to achieve long life.

Description

TECHNICAL FIELD

[0001] The present application relates to a deep groove ball bearing. BACKGROUND

[0002] Motors for air-conditioning fans, cooling fans, ventilation fans, cleaners, washing machines, and the like, general-purpose motors, servo motors, stepping motors, and the like, and rotating shafts of machine tools, encoders, and the like, are supported by rolling bearings in a rotatable manner. In rolling bearings for such uses, a deep groove ball bearing is often used, which is capable of bearing axial loads in both directions in addition to radial loads, has a small frictional torque, and is suitable for uses requiring high-speed rotation, low noise, and low vibration. The raceway of the deep groove ball bearing is a deep groove in the shape of a circular arc, and a seal member is attached to both axial sides, with lubricating grease enclosed in the bearing space.

[0003] Further, as a single-row ball bearing used in a motor of a washing machine or the like, a deep groove ball bearing in which the wall thickness of an inner ring is set to be 1.5 times or more the wall thickness of an outer ring to increase the rigidity of the inner ring and prevent the inner ring from being subjected to creep is known (see, for example, Patent Literature 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2012-13116 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Further, in an encoder, a disc slit is used to read position information. Further, as the width of the slit has been narrowing year by year, reading errors sometimes occur due to contamination of the disc. In a deep groove ball bearing of a rolling bearing used in an encoder or the like, it is required to suppress leakage of lubricating grease and reduce generation of dust, and further improvement is needed.

[0009] The single-row ball bearing described in Patent Literature 1 has a seal member disposed in close proximity to a seal groove provided in an inner ring in a non-contact manner, but does not consider suppressing leakage of lubricating grease and generation of dust.

[0010] Further, in a motor or the like, miniaturization and weight reduction are required, and the rolling bearing used is also required to be narrow.

[0011] The present application has been achieved in view of the above problems, and aims to provide a deep groove ball bearing that can achieve narrow width and weight reduction, ensure load capacity, and suppress leakage of lubricating grease to achieve long life.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The above object of the present application is achieved by the following structure.

[0014] A deep groove ball bearing comprising:

[0015] An outer ring provided with an outer ring raceway groove on an inner diameter surface;

[0016] An inner ring provided with an inner ring raceway groove on an outer diameter surface;

[0017] A plurality of balls disposed between the outer ring raceway groove and the inner ring raceway groove in a freely rolling manner; and

[0018] A seal member fixed to the outer ring, disposed in contact with or non-contact with a seal groove formed in a shoulder portion of the inner ring, and sealing a space between the outer ring and the inner ring, wherein

[0019] An axial sectional width of the deep groove ball bearing is smaller than a radial sectional height,

[0020] A wall thickness of the inner ring is larger than a wall thickness of the outer ring,

[0021] A pitch diameter of the balls is larger than an intermediate diameter between an inner diameter of the inner ring and an outer diameter of the outer ring, and

[0022] A radial dimension between an outer diameter of the shoulder portion of the inner ring and an inner diameter of the seal member is larger than the wall thickness of the outer ring.

[0023] Inventive Effects

[0024] According to the deep groove ball bearing of the present application, the axial sectional width is smaller than the radial sectional height, and thus narrow width and light weight can be achieved. In addition, since the wall thickness of the inner ring is larger than the wall thickness of the outer ring and the pitch diameter of the balls is larger than the intermediate diameter between the inner diameter of the inner ring and the outer diameter of the outer ring, the number of balls can be increased, and the load capacity of the deep groove ball bearing can be ensured to prolong the life.

[0025] Further, since the radial dimension between the outer diameter of the shoulder portion of the inner ring and the inner diameter of the seal member is larger than the wall thickness of the outer ring, the leakage of lubricating grease can be effectively suppressed to prolong the life of the deep groove ball bearing. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a main sectional view of a deep groove ball bearing according to an embodiment of the present application.

[0027] Figure 2 is an explanatory view showing the intervals of the balls from each other in the deep groove ball bearing of Figure 1

[0028] Figure 3 ​is a main part sectional view for explaining a space volume of a bearing space.

[0029] Figure 4 is a main part sectional view of a deep groove ball bearing related to a first modification example.

[0030] Figure 5 is a main part sectional view of a deep groove ball bearing related to a second modification example.

[0031] Figure 6 is a main part sectional view of a deep groove ball bearing related to a third modification example.

[0032] Figure 7 is a main part sectional view of a deep groove ball bearing related to a fourth modification example.

[0033] Figure 8 is a main part sectional view of a deep groove ball bearing related to a fifth modification example.

[0034] Figure 9 is a main part sectional view of a deep groove ball bearing related to a sixth modification example.

[0035] Figure 10 is a main part sectional view of a deep groove ball bearing related to a seventh modification example.

[0036] Figure 11 is a main part sectional view of a deep groove ball bearing related to an eighth modification example.

[0037] Figure 12 is a main part sectional view of a deep groove ball bearing related to a ninth modification example.

[0038] Figure 13 is a main part sectional view of a deep groove ball bearing related to a tenth modification example.

[0039] Figure 14 is a main part sectional view of a deep groove ball bearing related to an eleventh modification example.

[0040] Figure 15 is a main part sectional view of a deep groove ball bearing related to a twelfth modification example.

[0041] Figure 16 is a main part sectional view of a deep groove ball bearing related to a thirteenth modification example.

[0042] Figure 17 is a main part sectional view for explaining a process of sealing a lubricating grease in a deep groove ball bearing in Figure 16

[0043] Figure 18 is a main part sectional view for explaining a process of sealing a lubricating grease in a deep groove ball bearing in ​

[0044] Symbol Explanation

[0045] 10 Deep groove ball bearing

[0046] 11 Outer ring

[0047] 11a Outer ring raceway groove

[0048] 12 Inner ring

[0049] 12a Inner ring raceway groove

[0050] 13, 13A Ball

[0051] 15, 15A, 15B, 15C, 15D, 15E Sealing member

[0052] 16 Mandrel

[0053] 17 Sealing portion

[0054] 17b Lip portion

[0055] 17e Auxiliary lip portion

[0056] S Bearing space

[0057] b Radial dimension between outer diameter of inner ring and inner diameter of sealing member

[0058] c Wall thickness of inner ring

[0059] d Wall thickness of outer ring

[0060] G Grease

[0061] MD Intermediate diameter of inner diameter of inner ring and outer diameter of outer ring

[0062] PCD Pitch circle diameter DETAILED DESCRIPTION

[0063] Hereinafter, an embodiment of a deep groove ball bearing according to the present application and a modification example thereof will be described in detail based on the drawings.

[0064] As shown in Figure 1 , the deep groove ball bearing 10 of the present embodiment is provided with: an outer ring 11 having an outer ring raceway groove 11a on an inner diameter surface; an inner ring 12 having an inner ring raceway groove 12a on an outer diameter surface; a plurality of balls 13 rollingly arranged between the outer ring raceway groove 11a and the inner ring raceway groove 12a; a crown-shaped retainer 14 made of resin that holds the balls 13 at a prescribed interval in the circumferential direction; and a pair of sealing members 15 that are fixed to the inner diameter surface of the outer ring 11 on both axial sides and seal the bearing space S between the outer ring 11 and the inner ring 12. The bearing space S is preliminarily filled with grease. Further, in Figure 1 , the illustration of the grease is omitted, butFigure 16 The numeral G in the attached diagram indicates lubricating grease.

[0065] In this embodiment, the outer ring raceway groove 11a and the inner ring raceway groove 12a are formed on the outer ring 11 and the inner ring 12 such that the axial center line CL of the ball 13 is at the axial midpoint of the deep groove ball bearing 10.

[0066] The sealing component 15 includes: a core rod 16, which is formed into a generally circular shape from a metal plate such as a steel plate; and a sealing part 17, which is made of an elastic material such as rubber fixed to the core rod 16.

[0067] The sealing portion 17 includes: an outer peripheral portion 17a, which is formed to cover the outer peripheral edge of the mandrel 16 and protrude outward in the radial direction; an annular lip 17b, which extends from the inner peripheral edge of the mandrel 16 in the radial direction inward; and a side portion 17c, which is fixed to the inner side surface 16a of the mandrel 16 and connects the outer peripheral portion 17a and the lip 17b. That is, the mandrel 16 is positioned axially outward of the sealing portion 17 when the sealing member 15 is mounted on the deep groove ball bearing 10. Therefore, even if oil from the grease that has seeped into the elastic material of the sealing portion 17 leaks out, leakage to the axially outward can be suppressed by the mandrel 16.

[0068] The outer peripheral portion 17a is engaged with the sealing mounting groove 11e formed at the axial end of the outer ring 11 by pressing or the like, thereby fixing the sealing member 15 to the outer ring 11.

[0069] The lip 17b slides into contact with the sealing groove 12d formed in the shoulder 12g of the inner ring 12 from the axially inner side, and the sealing member 15 forms a contact seal. Additionally, an auxiliary lip 17e is formed protruding axially from the radial center of the side portion 17c. The auxiliary lip 17e is disposed close to the edge 12e of the outer diameter surface 12b of the shoulder 12g of the inner ring 12 and the side surface 12f of the sealing groove 12d in a non-contact manner. Furthermore, in this embodiment, the edge 12e is chamfered.

[0070] Thus, the sealing member 15 of this embodiment seals the bearing space S between the outer ring 11 and the inner ring 12 from the outside through the lip 17b and the auxiliary lip 17e.

[0071] In this embodiment of the deep groove ball bearing 10, the axial cross-sectional width (i.e., the axial width of the outer ring 11 and the inner ring 12) W is less than the radial cross-sectional height (i.e., the radial distance between the outer diameter of the outer ring 11 and the inner diameter of the inner ring 12) H (W < H). This allows for a narrower and lighter deep groove ball bearing 10, and also enables a shorter shaft (not shown) that engages with the inner ring 12.

[0072] Further, in the present embodiment, a low-dust generating grease is enclosed in a space in the deep groove ball bearing 10 that is sealed by the seal member 15, i.e., a bearing space S surrounded by the seal member 15, the inner ring 12, the outer ring 11, and the balls 13. This low-dust generating grease contains a base oil, a thickening agent, and an additive that are appropriately selected, and thus can suppress the amount of dust generated from the deep groove ball bearing 10. In particular, in the case where the deep groove ball bearing 10 is used for a rotating shaft of a servo motor, it is possible to prevent contamination of an encoder.

[0073] The low-dust generating grease used in the present embodiment contains a base oil that is formulated with at least one selected from a synthetic hydrocarbon oil and an ether oil, a thickening agent that contains a urea compound, and an additive that contains only non-metal elements, and the amount of mixing of metal elements in the low-dust generating grease is 30 ppm or less. The low-dust generating grease is described in more detail.

[0074] The base oil contained in the low-dust generating grease is preferably a synthetic oil having excellent lubricating properties and torque properties, and contains at least one of a synthetic hydrocarbon oil and an ether oil having excellent dust generating properties. As the synthetic hydrocarbon oil, poly-alpha olefin oil and the like can be given, and as the ether oil, dialkyl diphenyl ether oil, alkyl triphenyl ether oil, alkyl tetraphenyl ether oil, and the like can be given.

[0075] In particular, in view of high-temperature durability, it is preferable to use alkyl diphenyl ether as an essential component (50% by weight or more of the base oil component). Further, from the viewpoint of low-temperature fluidity, it is most preferable to use a synthetic hydrocarbon oil as the base oil.

[0076] Further, in order to further improve the lubricating properties, an ester oil can be formulated as necessary. As the formulated ester oil, polyol ester oil, aromatic ester oil is preferable. In view of dust characteristics, the ester oil is preferably less than 50% by weight of the base oil component.

[0077] The kinematic viscosity of the base oil is preferably 30 to 180 mm 2 / sec, and particularly preferably 30 to 150 mm 2 / sec. This is because, by making the kinematic viscosity of the base oil 30 mm 2 / sec or more, evaporation at high temperatures can be suppressed, and by making it 180 mm 2 / sec or less, an increase in frictional torque and an increase in the amount of dust can be suppressed.

[0078] The low-dust generating grease contains a thickening agent that contains a urea compound having an effect of improving high-temperature properties. As the urea compound, diurea, triurea, tetraurea, polyurea, and the like can be given. These urea compounds can contain different elements other than metal elements in their molecules, and can also have a substituent that does not contain a metal atom.

[0079] The content of the urea compound in the grease is not particularly limited as long as it is an amount that forms a grease form, and is preferably in the range of approximately 10 to 30% by weight. The urea compound has the effect of improving the high-temperature properties of the grease, particularly the mechanical stability at high temperatures, and by being set to 10% by weight or more, its effect can be sufficiently obtained. On the other hand, by being set to 30% by weight or less, the amount of dusting can be suppressed, and the rise in torque and the deterioration of lubricating properties can be prevented. In addition, in order to suppress the amount of dusting, an appropriate hardness is required. Therefore, it is preferable to make the mixed consistency of the grease 190 to 230.

[0080] In addition, the low-dusting grease contains an additive that contains only non-metal elements. The following shows the kinds of additives and their preferred compounds, among which, compounds not containing sulfur, chlorine, and phosphorus are preferred. In order to satisfy the requirement for rust resistance, an anti-rust agent is preferably added as the additive. In addition, if necessary, an antioxidant, an oiliness agent, a metal inactivator, and the like can be added. The following shows an example of an additive that can be used in the present application.

[0081] As the anti-rust agent, carboxylic acids such as succinic acid and their derivatives, non-ionic surfactants such as sorbitan, and the like can be used. In addition, as the antioxidant, amine-based and phenol-based antioxidants can be used, as the oiliness agent, long-chain fatty acid-based oiliness agents can be used, and as the metal inactivator, benzotriazole-based metal inactivators can be used, and the like.

[0082] Each of the above-described additives can be used individually or in appropriate combination.

[0083] As for the blending amount of the additive, each of the additives as a monomer is preferably 0.1% by weight or more of the total amount of the grease, whereby the effect of the additive can be obtained. However, in the case of individual use and combined use, the total amount is preferably 1% by weight or less of the total amount of the grease, whereby the explosive increase in the amount of dusting can be prevented.

[0084] The grease used in the present application is obtained by blending a prescribed amount of a thickening agent and an additive in the above-mentioned base oil listed according to a conventional method, and mixing using a mixing machine.

[0085] Note that, at the time of the kneading, metal is sometimes mixed into the grease from the kneader, the transfer container, or the like. Also, metal elements are sometimes contained as impurities in the raw materials. However, if the management during the process is performed sufficiently, the amount of the mixed-in metal can be suppressed to an extremely small amount, without impairing the effects of the present application. Therefore, the amount of the mixed-in metal into the grease is most preferably below the detection limit of the analysis device, and is preferably 30 ppm or less. However, if the technical field of the present application is considered, Li, Na, Al, Ca, Ni, Zn, Mo, Sn, Sb, Ba, and Pb are preferably 5 ppm or less. Also, for the same reason, Cl, P, and S are preferably 20 ppm or less.

[0086] Also, the amount of the enclosed grease into the bearing space S is set to 15 to 25% of the space volume. Here, as indicated by the grid lines of Figure 3 the space volume refers to the volume obtained by subtracting the volumes of the balls 13 and the retainer 14 from the space surrounded by the inner peripheral surface of the outer ring 11, the outer peripheral surface of the inner ring 12, and the pair of seal members 15.

[0087] If the amount of the enclosed grease is less than 15% of the space volume, the grease cannot spread over the raceway surfaces, the base oil of the grease cannot lubricate efficiently, and also the consumption of the grease is fast, so the life of the grease, and further the life of the bearing, can be shortened. On the other hand, if the amount of the enclosed grease exceeds 25% of the space volume, the dusting and leakage of the grease can be increased. Therefore, the amount of the enclosed grease is 15 to 25% of the space volume of the bearing space S.

[0088] Also, the wall thickness c of the inner ring 12 is set to be larger than the wall thickness d of the outer ring 11 (c > d). By making the wall thickness c of the inner ring 12 larger than the wall thickness d of the outer ring 11, the pitch circle diameter PCD of the balls 13 is made larger than the intermediate diameter MD of the inner diameter of the inner ring 12 and the outer diameter of the outer ring 11. That is, in the case where the outer diameter and the inner diameter of the bearing 10 are set to the same size, by increasing the wall thickness c of the inner ring 12, the pitch circle diameter PCD is increased compared to a deep groove ball bearing where the wall thicknesses of the outer ring and the inner ring are the same, the number of the balls 13 can be increased, and the load capacity can be improved to achieve long life. Also, the deep groove ball bearing 10 can improve the load capacity by increasing the number of the balls 13, even in the case where the balls 13 having a small diameter g are used to reduce the above-mentioned axial cross-sectional width W.

[0089] Also, the wall thickness c of the inner ring 12 is the radial dimension between the outer diameter surface 12b of the shoulder portion 12g of the inner ring 12 and the inner diameter surface 12c of the inner ring 12, and the wall thickness d of the outer ring 11 is the radial dimension between the inner diameter surface lib of the shoulder portion 11f of the outer ring 11 and the outer diameter surface lie of the outer ring 11.

[0090] Further, the radial dimension b between the outer diameter of the shoulder 12g of the inner ring 12 and the inner diameter of the seal member 15 is set to be larger than the wall thickness d of the outer ring 11 (b > d). Thus, the overlapping dimension in the radial direction between the side surface 12f of the seal groove 12d of the inner ring 12 and the seal member 15 becomes large. That is, the labyrinth gap formed between the side surface 12f of the seal groove 12d and the side portion 17c of the seal member 17 is formed long in the radial direction between the lip portion 17b and the auxiliary lip portion 17e, and the leakage of the lubricating grease can be suppressed. Further, since the radial cross-sectional height H is secured, the overlapping dimension in the radial direction between the inner ring and the seal member can be easily secured.

[0091] Further, the radial dimension b between the outer diameter of the inner ring 12 and the inner diameter of the seal member 15 is larger than the radial dimension e between the inner diameter of the inner ring 12 and the inner diameter of the seal member 15 (b > e). Thus, the above-described labyrinth gap can be easily formed long in the radial direction.

[0092] Further, when the radial dimension between the outer diameter of the inner ring raceway groove 12a and the inner diameter of the inner ring 12 is set to f, the diameter of the ball 13 is set to g, and the radial dimension between the inner diameter of the outer ring raceway groove 11a and the outer diameter of the outer ring 11 is set to h, the relationship between the dimensions is f > g > h. Thus, the inertia of the not-shown shaft fitted to the inner ring 12 can be reduced.

[0093] Further, the radius i (= g / 2) of the ball 13 is larger than the axial dimension j of the axial end surface of the ball 13 and the axial end surface lid of the outer ring 11 (i > j), and a ball 13 having a larger diameter is used, and thus, in the case where the axial length is the same, the load capacity is increased compared to a standard deep groove ball bearing, and the life of each ball 13 can be lengthened.

[0094] Further, also with reference to Figure 2 the diameter g of the ball 13 is larger than the circumferential interval k between the adjacent balls 13 (g > k), and more balls 13 are provided, and thus, compared to a ball 13 having a smaller circumferential interval k between the adjacent balls 13 (g < k), the load received by each ball 13 is dispersed and becomes small, and thus, the life of each ball 13 can be lengthened.

[0095] Further, since the radial dimension p between the outer diameter of the shoulder 12g of the inner ring 12 and the inner diameter of the core rod 16 of the seal member 15 is larger than the radial dimension n between the inner diameter of the core rod 16 of the seal member 15 and the inner diameter of the seal member 15 (p > n), the deformation of the seal member 15 when the seal member 15 is mounted to the deep groove ball bearing 10 can be suppressed, and the leakage of the lubricating grease can be further reduced.

[0096] As explained above, the deep groove ball bearing 10 of the present embodiment makes the axial sectional width W smaller than the radial sectional height H (W < H), enabling narrow width and light weight. Further, the above structure is achieved by making the wall thickness c of the inner ring 12 larger than the wall thickness d of the outer ring 11, so that the pitch circle diameter PCD of the balls 13 is larger than the intermediate diameter MD of the inner diameter of the inner ring 12 and the outer diameter of the outer ring 11, and thus the number of balls can be increased, and the load capacity of the deep groove ball bearing can be ensured to extend the life.

[0097] Further, since the radial dimension b between the outer diameter of the shoulder 12g of the inner ring 12 and the inner diameter of the seal member 15 is set to be larger than the wall thickness d of the outer ring 11 (b > d), the overlapping dimension in the radial direction of the side surface 12f of the seal groove 12d of the inner ring 12 and the seal member 15 becomes large, that is, the labyrinth gap formed between the side surface of the seal member 15 and the side surface 12f of the seal groove 12d becomes long, and the leakage of the enclosed grease is suppressed.

[0098] Further, since the radial dimension b between the outer diameter of the shoulder 12g of the inner ring 12 and the inner diameter of the seal member 15 is larger than the radial dimension e between the inner diameter of the inner ring 12 and the inner diameter of the seal member 15 (b > e), the leakage of the grease can be further suppressed.

[0099] Further, by making the wall thickness c of the inner ring 12 larger than the wall thickness d of the outer ring 11 (c > d), the radial length of the side surface 12f of the seal groove 12d of the inner ring 12 can be increased, and the labyrinth performance is improved to further suppress the leakage of the grease.

[0100] Further, since a prescribed low-dust generating grease is enclosed in the bearing space S sealed by the seal member 15, the generation of dust can be suppressed. Further, since the low-dust generating grease has a small content of metal elements, the scattering of metal elements can be reduced. Furthermore, the above-mentioned preferable low-dust generating grease has excellent flowability, lubricity, and high-temperature characteristics, and also has more excellent low-dust generating property, and thus a deep groove ball bearing 10 having excellent mechanical stability at high temperatures and torque performance can be obtained, and the pollution to the surroundings can be reduced.

[0101] Hereinafter, the deep groove ball bearings related to each modification example of the present application will be described with reference to the drawings. Further, in the description of the deep groove ball bearings of each modification example, mainly the parts different from the above-described embodiment will be described, and the same or equivalent parts as those of the above-described embodiment will be denoted by the same reference numerals or equivalent reference numerals and the description will be simplified or omitted.

[0102] (First Modification Example)

[0103] As Figure 4As shown, in the deep groove ball bearing 10a of the first modified example, the lip 17b of the sealing member 15A constitutes a non-contact seal that does not contact the sealing groove 12d. Therefore, by setting both the lip 17b and the auxiliary lip 17e as non-contact seals, the rotational torque can be reduced. In addition, by setting them as non-contact seals, grease leakage is reduced, but the labyrinth clearance is long, so grease leakage is less than before.

[0104] (Second variation)

[0105] like Figure 5 As shown, in the second modified example of the deep groove ball bearing 10b, the sealing member 15B has a plurality of additional auxiliary lips 17f between the lip 17b and the auxiliary lips 17e, which do not contact the side surface 12f of the sealing groove 12d. This further improves the sealing performance of the sealing member 15B.

[0106] (Third variation)

[0107] like Figure 6 As shown, in the third modified deep groove ball bearing 10c, a sealing member 15C (metal shield) is fixed to the sealing mounting groove 11e on the axial side, preferably on the closed side of the cage where grease is less likely to leak. Therefore, by using the sealing member 15C, which is not in contact with the inner ring 12, on the axial side, the rotational torque can be reduced and low cost can be achieved.

[0108] (Fourth variation)

[0109] like Figure 7 As shown, in the fourth modified deep groove ball bearing 10d, the mandrel 16 of the sealing member 15D is disposed axially inside the sealing portion 17. In this case, the sealing member 15D can be either an auxiliary lip 17e that engages separately with the mandrel 16, or it can be a structure without the auxiliary lip 17e. By configuring it in this way, the lip 17b can be made less likely to detach from the mandrel 16.

[0110] (Fifth variation)

[0111] like Figure 8 As shown, in the fifth modified deep groove ball bearing 10e, a steel cage 14A is used instead of a resin cage 14. This improves the durability of the cage 14A and extends the lifespan of the deep groove ball bearing 10e.

[0112] (Sixth variation)

[0113] like Figure 9 As shown, in the deep groove ball bearing 10f of the sixth modification, ceramic balls 13A are used instead of steel balls 13, thereby achieving a longer life of balls 13A and suppressing electro-corrosion.

[0114] (Seventh variation)

[0115] like Figure 10 As shown, in the seventh modified deep groove ball bearing 10g, the lip 17b of the sealing member 15E slides into contact (inner contact) with the side surface 12f of the inner ring 12 from the axially outer side. By making the lip 17b into inner contact with the side surface 12f of the inner ring 12, the contact surface pressure between the lip 17b and the side surface 12f can be appropriately maintained, corresponding to the direction in which preload is applied to the deep groove ball bearing 10g. In addition, by using the sealing member 15E, it can play a role that is beneficial to sealing performance, corresponding to the airflow direction within the deep groove ball bearing 10g.

[0116] Alternatively, the sealing member 15E may be provided only on one axial side, while the sealing member 15 of the above embodiment is provided on the other axial side.

[0117] (Eighth variation)

[0118] like Figure 11 As shown, in the deep groove ball bearing 10h of the eighth modified example, two O-rings 20 are installed in the O-ring groove 11g formed on the outer diameter surface 11c of the outer ring 11. The O-rings 20 use friction with a housing (not shown) embedded in the outer ring 11 to prevent creep of the outer ring 11.

[0119] (Ninth variation)

[0120] like Figure 12 As shown, in the deep groove ball bearing 10i of the ninth modified example, a plurality of axially projecting protrusions are provided in a ring shape on the side 12f of the sealing groove 12d of the inner ring 12. A non-contact seal is formed between the plurality of protrusions 12h and the side 17c of the sealing portion 17 to further suppress grease leakage.

[0121] (Tenth variation)

[0122] like Figure 13 As shown, in the tenth modified example of the deep groove ball bearing 10j, the side surface 12f of the sealing groove 12d of the inner ring 12 is formed with a generally trapezoidal cross section, that is, its axial width gradually narrows as it moves radially outward. This improves the machinability of the inner ring 12. Furthermore, by making... Figure 12 The auxiliary lip 17e extends close to the inner ring 12, which can reduce the gap between the auxiliary lip 17e and the inner ring 12 and suppress grease leakage, and is therefore preferred.

[0123] (Eleventh variation)

[0124] like Figure 14As shown, in the deep groove ball bearing 10k of the eleventh modification, the balls 13 are arranged offset in the axial direction with respect to the outer ring 11 and the inner ring 12. Specifically, the axial dimension 1 from the axial center line CL of the balls 13 to one end face 21a of the deep groove ball bearing 10k is set to be larger than the axial dimension m from the axial center line CL of the balls 13 to the other end face 21b of the deep groove ball bearing 10k (1 > m).

[0125] Therefore, on the one end face 21a side where the axial dimension 1 from the axial center line CL of the balls 13 to the one end face 21a of the deep groove ball bearing 10k is set to be larger, interference of the retainer 14 with the seal member 15 is less likely to occur. In addition, on the other end face 21b side where there is no possibility of interference of the retainer 14 with the seal member 15, the axial dimension can be shortened, and the axial length of the deep groove ball bearing 10k is shortened.

[0126] (Twelfth Modification)

[0127] As shown, in the deep groove ball bearing 10k of the eleventh modification, the balls 13 are arranged offset in the axial direction with respect to the outer ring 11 and the inner ring 12. Specifically, the axial dimension 1 from the axial center line CL of the balls 13 to one end face 21a of the deep groove ball bearing 10k is set to be larger than the axial dimension m from the axial center line CL of the balls 13 to the other end face 21b of the deep groove ball bearing 10k (1 > m). Figure 15 As shown, in the deep groove ball bearing 10l of the twelfth modification, an auxiliary lip portion 17e is protrusively formed toward the axially inner side at the radial middle of the side portion 17c of the seal portion 17. The auxiliary lip portion 17e is in contact with the outer diameter surface 12b of the shoulder portion 12g of the inner ring 12 and the edge portion 12e of the side surface 12f of the seal groove 12d, and constitutes a contact lip.

[0128] Therefore, the seal member 15 has the auxiliary lip portion 17e as a contact lip on the upstream side of the labyrinth gap, and thus the outflow and evaporation of the lubricating grease, the base oil of the lubricating grease, can be suppressed, the lubricating grease life can be extended, and contamination of the surroundings can also be prevented.

[0129] In addition, the contact site of the auxiliary lip portion 17e is not limited to the edge portion 12e of the inner ring 12, but can also be the outer diameter surface 12b of the shoulder portion 12g near the edge portion 12e, or the side surface 12f of the seal groove 12d.

[0130] In addition, in this modification, the seal member 15 has the lip portion 17b in contact with the seal groove 12d, but can also have a non-contacting lip portion 17b arranged separately from the seal groove 12d.

[0131] (Thirteenth Modification)

[0132] As shown, in the deep groove ball bearing 10k of the eleventh modification, the balls 13 are arranged offset in the axial direction with respect to the outer ring 11 and the inner ring 12. Specifically, the axial dimension 1 from the axial center line CL of the balls 13 to one end face 21a of the deep groove ball bearing 10k is set to be larger than the axial dimension m from the axial center line CL of the balls 13 to the other end face 21b of the deep groove ball bearing 10k (1 > m). Figure 16 As shown, in the deep groove ball bearing 10m of the thirteenth modification, the above-described low-dust generating lubricating grease G is enclosed in the space of the deep groove ball bearing 10 sealed by the seal member 15, that is, the bearing space S surrounded by the seal member 15, the inner ring 12, the outer ring 11, and the balls 13.

[0133] In particular, the grease G is enclosed in the space on the axial one side relative to the axial center line CL of the balls 13 of the opening side of the pockets P of the crown type retainer 14, and preferably on the inner peripheral surface side of the outer ring 11.

[0134] Specifically, as shown in FIG. 6, the grease G is enclosed in a state where the outer ring 11, the inner ring 12, the balls 13, the retainer 14, and the seal member 15 on the axial one side are assembled, and the seal member 15 on the axial other side is not assembled. After the grease G is enclosed, the seal member 15 on the axial other side is installed to the seal installation groove 11e of the outer ring 11. Figure 17

[0135] Further, it can also be that, at the time of enclosing the grease G, the seal member 15 on the axial other side is also removed, and after the grease G is enclosed, the pair of seal members 15 are installed to the seal installation groove 11e of the outer ring.

[0136] In the present embodiment, the grease G is enclosed on the axial one side, and preferably on the inner peripheral surface side of the outer ring 11, which means that, in a state before trial operation, the space region is enclosed on the axial one side relative to the axial center line CL of the balls 13, and on the inner peripheral surface side of the outer ring 11 relative to the pitch circle diameter PCD of the balls. However, depending on the enclosed amount, the above-mentioned enclosure of the grease G also includes a state where, in a state before trial operation, the space region is enclosed on the axial one side more than on the axial other side relative to the axial center line CL of the balls 13, and on the inner peripheral surface side of the outer ring 11 more than on the outer peripheral surface side of the inner ring 12 relative to the pitch circle diameter PCD of the balls.

[0137] Thus, the grease G can be easily enclosed in the space on the axial one side of the crown type retainer 14 where the circular ring portion 14b is not present. Further, in a case where the grease G is enclosed on the inner peripheral surface side of the outer ring, i.e., away from the seal position of the seal groove 12d of the inner ring 12 and the seal member 15 that separates the bearing space S from the outside, the dusting and leakage of the grease can be suppressed, and contamination of the surroundings can be prevented.

[0138] Further, in a case where the grease G is enclosed on the inner peripheral surface side of the outer ring 11 that is a stationary ring, the amount of the grease that is stirred by being attached to the balls 13 and the like at the time of operation of the bearing is small, and a sharp temperature rise can be suppressed.

[0139] Further, the pair of seal members 15, 15 have mutually different appearances, and the appearance of either seal member 15 has recognition indicating the axial one side or the other side. Specifically, in the present modification, as shown in FIG. 6, the seal member 15 on the axial one side has a color different from that of the seal member 15 on the axial other side. Figure 18 ​As shown, an identification mark 30 is provided on the axial outer side of the core rod 16 of the seal member 15 on the one axial side, for example, in a manner that a portion of the seal member 15 is formed in a convex shape, so as to have a different appearance from the seal member on the other axial side. The identification mark 30 is recognized as indicating the side on which the lubricating grease is previously sealed, i.e., the one axial side.

[0140] Thus, the direction in which the lubricating grease is sealed can be identified from the appearance of the bearing, and the direction of resistance to contamination can be managed and the device such as an encoder can be assembled. That is, when the deep groove ball bearing 10 is assembled in the device, the deep groove ball bearing 10 is configured such that the member affected by the lubricating grease, e.g., the disc having a slit in the case of an encoder, is located on the other axial side of the deep groove ball bearing 10.

[0141] In addition, by using the axial outer side of the core rod, it is possible to easily form an appearance having an identification ability.

[0142] Further, as a method of imparting an appearance having an identification ability to the seal member 15, in addition to the above, the color of the axial outer side of the seal member 15 can be specified as mutually different colors. In addition, the shapes of the pair of seal members 15, 15 can be made different from each other, or either of the seal members 15 can include a core rod and an elastic material, and the other of the seal members 15 can be configured by a shield, or one of the seal members can be subjected to engraving.

[0143] Further, the present application is not limited to the above-described embodiments and modified examples, and can be appropriately modified and improved.

[0144] For example, in the above-described embodiments and each modified example, generally, the inner ring 12 and the outer ring 11 are subjected to heat treatment such as quenching and tempering to achieve an increase in hardness. However, the deep groove ball bearing of the present application can further increase the surface hardness of the inner ring 12 and the outer ring 11 by changing the heat treatment to nitrocarburizing treatment, and can achieve an increase in fatigue life of the surfaces (inner ring raceway grooves 12a and outer ring raceway grooves 11a) of the inner ring 12 and the outer ring 11. Further, the nitrocarburizing treatment can be applied only to the inner ring 12.

[0145] In addition, as in the present embodiment, in the case of using the crown type retainer 14, depending on the fact that the seal members 15 are different on both axial sides and the like, the case of the deep groove ball bearing being asymmetric in the axial direction, and the arrangement of the members (e.g., an encoder) around the deep groove ball bearing, the assembly direction of the crown type retainer 14 can also be the opposite direction to Figure 1 That is, the side of the crown type retainer 14 on which the annular portion is arranged can be the opposite side to the side relative to the balls 13. In this case, the direction in which the lubricating grease is sealed is also changed depending on the change in the assembly direction of the retainer 14.

[0146] Further, in the above-described embodiment, the grease is sealed from the opening side of the pockets, i.e., from one axial side, but the retainer of the present application is not limited to the crown retainer, and can be a wave retainer or the like having a circular ring portion on both axial sides. In this case, the grease is sealed from either one of the axial sides as the one axial side.

[0147] As described above, the following is disclosed in this specification.

[0148] (1) A deep groove ball bearing comprising:

[0149] an outer ring provided with an outer ring raceway groove on an inner diameter surface;

[0150] an inner ring provided with an inner ring raceway groove on an outer diameter surface;

[0151] a plurality of balls freely rolling between the outer ring raceway groove and the inner ring raceway groove; and

[0152] a seal member fixed to the outer ring, disposed in contact with or out of contact with a seal groove formed in a shoulder portion of the inner ring, and sealing a space between the outer ring and the inner ring, wherein

[0153] an axial sectional width of the deep groove ball bearing is smaller than a radial sectional height,

[0154] a wall thickness of the inner ring is larger than a wall thickness of the outer ring,

[0155] a pitch diameter of the balls is larger than an intermediate diameter between an inner diameter of the inner ring and an outer diameter of the outer ring, and

[0156] a radial dimension between the outer diameter of the shoulder portion of the inner ring and an inner diameter of the seal member is larger than the wall thickness of the outer ring.

[0157] According to this structure, the axial sectional width can be made smaller than the radial sectional height, achieving narrowness and lightness. Further, by increasing the pitch diameter, the number of balls can be increased, the load capacity of the deep groove ball bearing can be ensured, and the life can be extended. Moreover, the radial overlapping dimension of the inner ring and the seal member can be increased, the sealing performance can be improved to suppress leakage of the grease, and the deep groove ball bearing can be long-lived.

[0158] (2) The deep groove ball bearing according to (1), wherein

[0159] a low-dust generating grease is sealed in the space sealed by the seal member,

[0160] The low-dust generating grease contains: a base oil, the base oil being formulated with at least one selected from synthetic hydrocarbon oils and ether oils; a thickening agent, the thickening agent including a urea compound; and an additive, the additive including only non-metal elements, the amount of mixing of metal elements being 30 ppm or less.

[0161] According to this structure, since a prescribed low-dust generating grease is enclosed in the bearing space S sealed by the sealing member 15, generation of dust can be suppressed, and contamination of the surroundings can be prevented. In addition, the low-dust generating grease contains a urea compound as a thickening agent, so the high-temperature characteristics of the grease can be improved.

[0162] (3) The deep groove ball bearing according to (2), wherein

[0163] The base oil has a kinematic viscosity at 40°C of 30 to 180 mm 2 / sec, the additive is contained in an amount of 0.1 to 1% by weight of the total amount of the low-dust generating grease, and the mixed consistency of the low-dust generating grease is 190 to 230.

[0164] According to this structure, by prescribing the kinematic viscosity of the above base oil, the flow characteristics and lubricating properties of the low-dust generating grease can be improved, and by controlling the amount of additive and the mixed consistency of the low-dust generating grease, a more excellent low-dust generating property can be obtained.

[0165] (4) The deep groove ball bearing according to (2) or (3), wherein

[0166] The additive including only non-metal elements is a carboxylic acid and a derivative thereof, a nonionic surfactant, an amine-based antioxidant, a phenol-based antioxidant, a long-chain fatty acid-based oiliness agent, a benzotriazole-based metal inactivator, or a mixture of combinations thereof.

[0167] According to this configuration, the above additive can function as a rust preventive agent, an antioxidant, an oiliness agent, or a metal inactivator.

[0168] (5) The deep groove ball bearing according to any one of (1) to (4), wherein

[0169] The enclosed amount of the grease enclosed in the space is 15 to 25% of the volume of the space.

[0170] According to this structure, the enclosed amount of the grease enclosed in the space is 15 to 25% of the volume of the space, so the life of the grease can be ensured, and further the life of the bearing can be ensured, and generation of dust and leakage of the grease can be suppressed, and contamination of the surroundings can be prevented.

[0171] (6) The deep groove ball bearing according to any one of (1) to (5), wherein

[0172] The seal member has an auxiliary lip portion that protrudes toward the axial inner side and contacts the outer diameter surface of the shoulder portion of the inner ring and the edge portion of the side surface of the seal groove or the vicinity of the edge portion.

[0173] According to this structure, since the auxiliary lip portion that constitutes a contact seal is provided, the outflow and evaporation of the lubricating grease, base oil of the lubricating grease can be suppressed, and contamination of the surroundings can be prevented.

[0174] (7) The deep groove ball bearing according to any one of (1) to (6), wherein

[0175] Further, a crown type retainer is provided, which is opened on the axial one side and has a plurality of pockets each retaining a plurality of the balls,

[0176] The lubricating grease is enclosed in the space on the axial one side.

[0177] According to this structure, the lubricating grease is enclosed on the axial one side, so the dusting and leakage of the lubricating grease from the axial other side can be suppressed, and contamination of the surroundings can be prevented.

[0178] (8) The deep groove ball bearing according to (7), wherein

[0179] The lubricating grease is enclosed on the inner peripheral surface side of the outer ring.

[0180] According to this structure, the dusting and leakage of the lubricating grease can be further suppressed.

[0181] (9) The deep groove ball bearing according to any one of (1) to (8), wherein

[0182] The lubricating grease is enclosed in the space on the axial one side, and

[0183] The pair of seal members have mutually different appearances, and the appearance of either one of the seal members has an identification indicating the axial one side or the other side.

[0184] According to this structure, the appearance of either one of the seal members has an identification indicating the axial one side or the other side in which the lubricating grease can be enclosed, so the direction in which the lubricating grease is enclosed can be identified from the appearance of the bearing, and the direction in which contamination is resistant can be managed and the device can be loaded.

[0185] (10) The deep groove ball bearing according to any one of (1) to (9), wherein

[0186] The seal member has a core rod and a seal portion including an elastic material that covers the core rod,

[0187] The core rod is disposed at a position that is axially outward of the seal portion.

[0188] According to this structure, the sealed low-dust grease can be prevented from leaking out more effectively through the mandrel.

[0189] The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0190] This application is based on Japanese patent applications filed on January 22, 2021 (Japanese Patent Application No. 2021-008898, Japanese Patent Application No. 2021-008899, Japanese Patent Application No. 2021-008900, and Japanese Patent Application No. 2021-008900).

[0191] Japanese patent application (2021-008901) filed on January 22, 2021 (Japanese Patent Application)

[0192] Japanese patent application filed on January 22, 2021 (2021-008902) and Japanese patent application filed on January 22, 2021 (Japan Special Application)

[0193] (2021-008903), the content of which is cited here for reference.

Claims

1. A deep groove ball bearing, characterized in that Possessing: an outer ring provided with an outer ring raceway groove on an inner diameter surface; an inner ring provided with an inner ring raceway groove on an outer diameter surface; a plurality of balls disposed between the outer ring raceway groove and the inner ring raceway groove in a freely rolling manner; and a seal member fixed to the outer ring, disposed in contact with or non-contact with a seal groove formed in a shoulder portion of the inner ring, and sealing a space between the outer ring and the inner ring, an axial sectional width of the deep groove ball bearing is smaller than a radial sectional height, a wall thickness of the inner ring is greater than a wall thickness of the outer ring, a pitch diameter of the balls is greater than an intermediate diameter of an inner diameter of the inner ring and an outer diameter of the outer ring, and a radial dimension between an outer diameter of the shoulder portion of the inner ring and an inner diameter of the seal member is greater than the wall thickness of the outer ring.

2. The deep groove ball bearing according to claim 1, wherein a low-dust generating grease is enclosed in the space sealed by the seal member, the low-dust generating grease contains: a base oil, the base oil being formulated with at least one selected from synthetic hydrocarbon oil and ether oil; a thickening agent, the thickening agent including a urea compound; and an additive, the additive including only non-metal elements, a mixed amount of metal elements in the low-dust generating grease is 30 ppm or less.

3. The deep groove ball bearing according to claim 2, wherein The base oil has a kinematic viscosity at 40°C of 30 to 180 mm 2 / sec, a content of the additive is 0.1 to 1% by weight of the total amount of the low-dust generating grease, and a mixed consistency of the low-dust generating grease is 190 to 230.

4. The deep groove ball bearing according to claim 2 or 3, wherein the additive including only non-metal elements is a carboxylic acid and a derivative thereof, a nonionic surfactant, an amine-based antioxidant, a phenol-based antioxidant, a long-chain fatty acid-based oiliness agent, a benzotriazole-based metal inactivator, or a mixture of combinations thereof.

5. The deep groove ball bearing according to any one of claims 1 to 3, wherein an enclosed amount of the grease enclosed in the space is 15 to 25% of a space volume.

6. The deep groove ball bearing according to any one of claims 1 to 3, wherein the seal member has an auxiliary lip portion protruding toward an axially inner side and contacting an outer diameter surface of the shoulder portion of the inner ring and a side surface of the seal groove or a vicinity of a rim portion of the side surface.

7. The deep groove ball bearing according to any one of claims 1 to 3, wherein the deep groove ball bearing further possesses a crown type retainer respectively having a plurality of pockets respectively retaining a plurality of the balls, the space is enclosed with a grease on an axially one side.

8. The deep groove ball bearing according to claim 7, wherein the grease is enclosed on an inner peripheral surface side of the outer ring.

9. The deep groove ball bearing according to any one of claims 1 to 3, wherein a grease is enclosed in the space on an axially one side, and a pair of the seal members fixed to the outer ring on both axially sides have mutually different appearances, and an appearance of either one of the seal members has an identification indicating the axially one side or the other side.

10. The deep groove ball bearing according to any one of claims 1 to 3, characterized in that the sealing member is provided with a core rod and a sealing portion containing an elastic material that covers the core rod, the core rod is disposed at a position that is axially outward of the sealing portion.

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