JPWO2015122099A1 - Ball bearing with seal - Google Patents

Abstract

A ball bearing with a seal according to the present invention is disposed between an outer ring having an outer ring raceway surface formed on an inner peripheral surface, an inner ring having an inner ring raceway surface formed on an inner ring outer peripheral surface, and an outer ring raceway surface and an inner ring raceway surface. And a sealing member fixed to the inner peripheral surface of the outer ring. The seal member includes an annular cored bar and an annular elastic part covering the cored bar, and the inner diameter φDc of the cored bar and the inner diameter φDr of the elastic part are 1.0 ≦ φDc / φDr ≦ 1. 0.1, the inner diameter φDc of the core metal and the outer diameter φDB of the inner ring 30 satisfy φDc / φDB <1.0.

Description

  The present invention relates to a ball bearing with a seal.

  In recent years, there has been a strong demand for energy saving in motors of electric vacuum cleaners (hereinafter also referred to as cleaners), and various technologies have been proposed to improve suction performance and reduce power consumption (for example, patents). References 1 and 2).

  In Patent Document 1, it is possible to improve the suction performance by blocking the air passing through the inside of the bearing by providing two seal plates covering the upper and lower sides of the outer ring and the inner ring in the bearing used for the motor of the cleaner. Have been described. One of the two seal plates is a contact-type seal plate that contacts the inner ring, and the other is a non-contact type seal plate.

  Patent Document 2 describes that the efficiency of the cleaner is improved by interposing a sealing plate between the bearing rings of the inner ring and the outer ring on both ends in the axial direction of the bearing. In this sealing plate, the direction in contact with the raceway is the same direction on both ends of the bearing. In these Patent Documents 1 and 2, it is stated that the suction efficiency of the cleaner is improved by reducing the mechanical friction loss of the bearing with a seal plate or a sealing plate, thereby reducing the current consumption.

  As described above, conventionally, a ball bearing with a seal provided with a seal plate or a seal plate is used for a motor of a cleaner. The configuration of conventional ball bearings with seals (conventional examples 1 to 4) will be further described with reference to FIGS.

  A ball bearing 100 with a seal of Conventional Example 1 shown in FIG. 16 includes a shield plate 140 fixed to the outer ring 120 on one end side in the axial direction, and a seal member 150 fixed to the outer ring 120 on the other end side in the axial direction. Prepare. The seal member 150 includes a metal core 151 and an elastic member 153 that covers the metal core 151, and a seal lip 156 is formed by the elastic member 153. The seal lip 156 is in sliding contact with the outer side of the bearing mainly in the seal groove 136 of the inner ring 130, thereby blocking the air flow in the bearing and ensuring the sealing performance. However, when the seal lip 156 contacts the inner ring 130, a frictional force is generated between the seal lip 156 and the seal groove 136, which increases the rotational torque of the bearing.

  A ball bearing 100A with seal of Conventional Example 2 shown in FIG. 17 includes a seal member 150A fixed to the outer ring 120 on one side in the axial direction. The seal member 150A includes a metal core 151A and an elastic member 153A that forms a seal lip 156A. The seal lip 156A is slidably contacted mainly inside the bearing in the seal groove 136 of the inner ring 130, thereby blocking the air flow in the bearing and ensuring the sealing performance.

  18 includes a shield plate 140 fixed to the outer ring 120 on one end side in the axial direction, and a seal member 150B fixed to the outer ring 120 on the other end side in the axial direction. Prepare. The seal member 150B of Conventional Example 3 includes a cored bar 151B and an elastic member 153B that forms a seal lip 156B. However, unlike the conventional examples 1 and 2, the seal lip 156B is a non-contact type seal member that does not contact the inner ring 130.

  A ball bearing 100C with a seal of Conventional Example 4 shown in FIG. 19 includes a seal member 150C fixed to the outer ring 120 on one side in the axial direction. The seal member 150 </ b> C includes a core metal 151 </ b> C and an elastic member 153 </ b> C that forms a seal lip 156 </ b> C, and the seal lip 156 </ b> C is a non-contact type seal member that does not contact the inner ring 130. Further, since the seal lip 156C of the seal member 150C is disposed in a non-contact state in the seal groove 136 of the inner ring 130, the labyrinth structure can improve the sealing performance.

Japanese Patent No. 3538006 Japanese Unexamined Patent Publication No. 2007-46767

  Since the sealing members shown in the conventional examples 1 and 2 are in contact with the inner ring, it is possible to ensure sealing performance. However, when the seal lip comes into contact with the seal groove of the inner ring, a frictional resistance is generated between the seal groove and the seal lip, resulting in a mechanical loss that increases the rotational torque of the bearing. Thereby, the suction efficiency of the cleaner may be reduced, and power consumption may increase.

  On the other hand, the non-contact type sealing member shown in Conventional Example 3 can reduce mechanical loss. However, since the seal lip is deformed by the air pressure passing through the inside of the bearing, the sealing performance of the bearing is not stable, and there is a possibility that the suction efficiency of the cleaner will vary. Further, in the non-contact type seal member shown in the conventional example 4, the seal lip deformed by receiving the air pressure passing through the inside of the bearing is brought into contact with the seal groove, so that frictional resistance is generated and mechanical loss of the bearing is caused. May occur, leading to a reduction in cleaner suction efficiency.

  In addition, there is a type in which a seal member in which the contact pressure between the seal lip and the inner ring is optimal is attached to the ball bearing with seal in accordance with the pressure load direction of the air pressure received by the bearing. In that case, one of two types of seal members having different contact directions between the seal lip and the inner ring is selected, and the selected seal member is attached to the bearing. Therefore, not only a process of selectively attaching the seal member to the bearing is required, but also a plurality of types of seal members must be prepared in advance, and the manufacturing process of the bearing becomes complicated.

  The present invention has been made in view of the above circumstances, and provides a sealed ball bearing capable of ensuring both the sealing performance of the bearing and the reduction of mechanical loss between the seal member and the inner ring. The second object is to provide a ball bearing with a seal that does not complicate the manufacturing process of the bearing.

The present invention has the following configuration.
(1) An outer ring having an outer ring raceway surface formed on an inner peripheral surface, an inner ring having an outer ring raceway surface formed on an outer peripheral surface, and a circumferentially movable manner between the outer ring raceway surface and the inner ring raceway surface. A ball bearing with a seal comprising a plurality of balls, and a seal member fixed to the inner peripheral surface of the outer ring,
The seal member comprises an annular cored bar and an annular elastic part that covers the cored bar,
The inner diameter φDc of the core metal of the seal member and the inner diameter φDr of the elastic portion satisfy 1.0 ≦ φDc / φDr ≦ 1.1,
A sealed ball bearing, wherein an inner diameter φDc of the cored bar of the seal member and an outer diameter φDB of the inner ring satisfy φDc / φDB <1.0.
(2) The inner peripheral edge of the elastic part is located in a seal groove formed on the outer peripheral surface of the inner ring,
The sealed ball bearing according to (1), wherein an axial distance Δd between the inner peripheral edge of the elastic portion and the seal groove is half the axial internal clearance.
(3) The elastic portion is located in a seal groove formed on the outer peripheral surface of the inner ring,
The sealed ball bearing according to (1), wherein the seal member is fixed to the outer ring in a non-contact state at all times with the seal groove.
(4) The sealed ball bearing according to (2), wherein the seal member is fixed to the outer ring so as to be in contact with the seal groove.
(5) The seal according to (4), wherein the inner peripheral side edge portion of the elastic portion that contacts the seal groove has an arc-shaped cross section in an axial cross section. Ball bearing.
(6) The elastic portion includes an inner lip on the inner side of the bearing and an outer lip on the outer side of the bearing, which are disposed in a seal groove formed on the outer peripheral surface of the inner ring, and the inner lip and the outer side. (1) The ball bearing with seal according to (1), wherein each of the lips has an arcuate cross section in an axial cross section.
(7) An axial distance between the inner lip and the inner wall of the seal groove inside the bearing, and an axial distance between the outer lip and the outer wall of the seal groove outside the bearing, At least one of the ball bearings with a seal according to (6), wherein the length is half the axial internal clearance before the preload is applied.
(8) The inner wall portion inside the bearing and the outer wall portion outside the bearing in the seal groove have the same inclination angle with respect to the radial direction of the inner ring, respectively (6) or (7) Sealed ball bearing.

  According to the present invention, it is possible to ensure both the sealing performance of the bearing and the reduction of mechanical loss between the seal member and the inner ring. Moreover, it can be set as the structure which does not make the manufacturing process of a bearing complicated.

It is sectional drawing which shows the ball bearing with a seal concerning a 1st embodiment. It is a graph which shows the relationship between the ratio of a metal core inner diameter and a seal lip inner diameter, and leakage pressure. It is sectional drawing which shows the ball bearing with a seal concerning 2nd Embodiment. It is sectional drawing which shows the ball bearing with a seal concerning the modification of 2nd Embodiment. It is sectional drawing which shows the ball bearing with a seal concerning 3rd Embodiment. It is a partially expanded sectional view of a seal lip. It is a principal part expanded sectional view of FIG. 5 of the state before preload provision. It is a principal part expanded sectional view of FIG. 5 of the state after preload provision. It is a principal part expanded sectional view of FIG. 5 of the state which loaded the air pressure after preload provision. It is sectional drawing which shows the ball bearing with a seal concerning 4th Embodiment. It is sectional drawing which shows the ball bearing with a seal concerning a 5th embodiment. It is a principal part enlarged view of FIG. It is a partially expanded sectional view of a seal lip. It is a principal part expanded sectional view which shows the state of the sealing member at the time of applying a preload and an air pressure to the ball bearing with a seal shown in FIG. It is a principal part expanded sectional view which shows the state of the seal member when the seal member of the ball bearing with seal shown in FIG. 12A is provided at the opposite bearing end and preload and air pressure are applied. FIG. 10 is an enlarged view of a main part of FIG. 9 showing another seal groove shape. It is the graph which showed the relationship between load pressure and motor consumption current, and the relationship between load pressure and leak air pressure about Examples 1-4 and the prior art examples 1-4. It is the graph which showed the relationship between load pressure and motor consumption current, and the relationship between load pressure and leak air pressure about Example 5 and Conventional Examples 1-3. It is sectional drawing of the ball bearing with a seal | sticker of the prior art example 1. It is sectional drawing of the ball bearing with a seal | sticker of the prior art example 2. It is sectional drawing of the ball bearing with a seal | sticker of the prior art example 3. It is sectional drawing of the ball bearing with a seal | sticker of the prior art example 4.

Hereinafter, the ball bearing with seal of the present invention will be described in detail with reference to the drawings.
(First embodiment)
In FIG. 1, sectional drawing of the ball bearing 10 with a seal | sticker which concerns on 1st Embodiment is shown.
The sealed ball bearing 10 of the present embodiment includes an outer ring 20 having an outer ring raceway surface 22 on an inner circumferential surface, an inner ring 30 having an inner ring raceway surface 32 on an inner ring outer circumferential surface 31, an outer ring raceway surface 22 and an inner ring raceway surface 32. A plurality of balls 15 provided in the circumferential direction so as to be freely rollable between them, a shield plate 40 disposed on one end side in the axial direction so as to close the space between the outer ring 20 and the inner ring 30, and on the other end side in the axial direction. And a sealing member 50 arranged in the same manner.

  The shield plate 40 is formed, for example, by forming a thin metal plate into an annular shape, and an outer peripheral portion 42 of the shield plate 40 is press-fitted into a groove 24 provided on one end side in the axial direction of the inner peripheral surface of the outer ring 20. It is fixed. The inner peripheral portion 44 of the shield plate 40 is bent inward of the bearing along the axial direction, and is disposed close enough to have a labyrinth clearance and a groove 34 provided at one end portion in the axial direction on the outer peripheral surface of the inner ring 30. Has been.

  The seal member 50 includes a cored bar 51 in which a thin metal plate is formed in an annular shape, and an elastic part 53 formed of an elastic material such as a synthetic resin that covers the cored bar 51. The outer peripheral portion 52 of the seal member 50 (elastic portion 53) is press-fitted and fixed in the groove 26 provided on the other axial end side of the inner peripheral surface of the outer ring 20. A seal lip 56 serving as an inner peripheral side edge of the seal member 50 (elastic portion 53) is disposed in a seal groove 36 provided on the other end side in the axial direction on the outer peripheral surface of the inner ring 30. Thus, the seal member 50 is a non-contact type seal member in which the seal lip 56 does not contact the inner ring 30 (the seal groove 36).

  The seal member 50 of this configuration is fixed to the outer ring 20 in a non-contact state with the seal groove 36, and the non-contact state with the seal groove 36 is maintained even when the bearing rotates. That is, the seal member 50 is fixed to the outer ring 20 in a non-contact state with the seal groove 36 at all times. Thereby, contact resistance does not generate | occur | produce between the seal lip 56 and the inner ring | wheel 30, and the mechanical loss at the time of bearing rotation can be reduced.

  Here, the relationship between the inner diameter dimension of the core metal 51 of the seal member 50 (the inner diameter dimension of the inner peripheral edge 54 of the core metal 51) φDc and the inner diameter dimension φDr of the seal lip 56 of the seal member 50 is 1.0. ≦ φDc / φDr ≦ 1.1 is satisfied.

  FIG. 2 shows the ratio (φDc / φDr) between the inner diameter dimension φDc of the core metal 51 of the seal member 50 and the inner diameter dimension φDr of the seal lip 56 of the seal member 50 when the pressure (air pressure) applied to the bearing is 10 kPa. ) And the leakage pressure. When the ratio of φDc / φDr is less than 1.0, the inner diameter of the core metal becomes larger than the inner diameter of the seal, and the core metal is exposed. Then, a seal lip cannot be provided on the inner peripheral side. When the ratio of φDc / φDr exceeds 1.1, the rigidity of the seal lip 56 is lowered, and the seal lip 56 is deformed when the bearing receives air pressure. In that case, the amount of air leakage increases.

  Thus, when the ratio of the inner diameter dimension φDc of the core metal 51 of the seal member 50 and the inner diameter dimension φDr of the seal lip 56 of the seal member 50 satisfies 1.0 or more and 1.1 or less, Rigidity increases, thereby reducing the amount of air leakage and ensuring the sealability of the bearing. The above items can be seen from FIG.

  Further, the relationship between the inner diameter dimension φDc of the core metal 51 of the seal member 50 and the outer diameter dimension φDB of the inner ring outer peripheral surface 31 of the inner ring 30 satisfies φDc / φDB <1.0. When the ratio between the inner diameter of the core metal and the outer diameter of the inner ring (φDc / φDB) is less than 1.0, the flow of air passing through the bearing from the opposite side of the seal member 50 is received by the highly rigid core metal 51. . Therefore, deformation of the seal lip 56 can be prevented.

  Therefore, according to this configuration, the contact between the seal lip 56 and the seal groove 36 can be prevented, so that mechanical loss during rotation of the bearing can be reduced. Further, by preventing the seal lip 56 from being deformed, the clearance between the seal lip 56 and the seal groove 36 can be maintained at an appropriate size, and the sealability of the bearing can be stabilized. In addition, leakage of a lubricant such as grease enclosed in the bearing can be prevented.

  As described above, according to the ball bearing 10 with a seal of the present embodiment, it is possible to achieve both of ensuring the sealability of the bearing and reducing mechanical loss between the seal lip of the seal member and the inner ring. is there. Thereby, when the ball bearing 10 with a seal | sticker is applied to a cleaner, variation in the suction | inhalation work rate of a cleaner can be prevented and energy saving property can be ensured.

(Second Embodiment)
Next, a ball bearing with seal 10A according to a second embodiment will be described with reference to FIG. Parts having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, the seal member 50A has an inner lip 57 that protrudes inward in the bearing along the axial direction in addition to the seal lip 56A at the inner peripheral edge located in the seal groove 36. . The seal member 50A is a non-contact type seal member as in the first embodiment, and no contact resistance is generated between the seal lip 56A and the inner ring 30, so that mechanical loss can be reduced. Also with the seal member 50A having such a shape, the rigidity of the seal lip 56A can be improved, and the sealability of the bearing can be secured.

(Modification of the second embodiment)
A sealed ball bearing 10A1 according to a modification of the second embodiment will be described with reference to FIG. Parts having the same configuration as in the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present modification, the seal lip 56A1 of the seal member 50A1 is branched into two in the seal groove 36. That is, the seal lip 56A1 extends toward the bearing rotation axis inward of the bearing along the axial direction, and extends toward the bearing rotation axis in parallel with the inner lip 56a1 outside the bearing from the inner lip 56a1. And an outer lip 56a2. The seal member 50A1 is a non-contact type seal member as in the first embodiment, and no contact resistance is generated between the seal lip 56A1 and the inner ring 30, so that mechanical loss can be reduced.

  Further, when the seal member 50A1 receives air pressure from the inside of the bearing, for example, the outer lip 56a2 is deformed by the influence of the air pressure. However, the inner lip 56a1 is not deformed because the received air pressure is lowered, and the pressure resistance performance can be maintained. Also with the seal member 50A1 having such a shape, the rigidity of the seal lip 56A1 (the inner lip 56a1 and the outer lip 56a2) can be improved, and the sealability of the bearing can be ensured.

(Third embodiment)
Next, a ball bearing 10B with a seal according to a third embodiment will be described with reference to FIGS. 5, 6, and 7A to 7C. Parts having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the ball bearing 10B with a seal according to this embodiment shown in FIG. 5, the contact pressure with respect to the seal groove 36 of the seal lip 56B is determined in consideration of the contact pressure when the bearing is built in the motor. Further, in the seal member 50B of this configuration, in the nominal state, the seal lip 56B is positioned in the seal groove 36 formed on the outer peripheral surface of the inner ring 30, and the seal lip 56B can come into contact with the seal groove 36. It is fixed to.

  FIG. 6 shows a partially enlarged sectional view of the seal lip 56B. The inner lip 56a1 of the inner peripheral edge 56a of the seal lip 56B has an arcuate cross section with a radius R1 in the axial cross section of the bearing.

  FIG. 7A is an enlarged cross-sectional view of a main part showing a state of the seal member 50A1 before applying preload in the ball bearing 10B with seal shown in FIG. 5, and FIG. 7B shows the seal member 50A1 after applying preload in the ball bearing 10B with seal. FIG. 7C is a principal part enlarged sectional view showing a state in which air pressure is applied after the preload is applied to the ball bearing 10B with the seal.

  As shown in FIG. 7A, before the preload is applied to the bearing, the seal lip 56B and the seal groove 36 are separated in the axial direction and the radial direction. The distance Δd between the seal lip 56B and the inner wall portion 38 inside the bearing of the seal groove 36 is half the axial internal clearance (nominal value) of the sealed ball bearing 10B.

  According to the above configuration, as shown in FIG. 7B, when a preload in the direction F1 in the figure is applied to the bearing, the inner ring 30 is displaced outwardly from the bearing, and the seal lip 56B and the seal groove 36 come into contact with each other and the distance Δd. Becomes 0. In this state, as shown in FIG. 7C, when air pressure is applied in the direction F2 in the figure, the seal lip 56B bends outward from the bearing, and the seal lip 56B and the seal groove 36 are in contact with each other with a low contact pressure. Get in contact. That is, the contact pressure between the seal lip 56B and the seal groove 36 is reduced, and the frictional resistance during the rotation of the bearing is reduced.

  Therefore, the seal member 50B of the present embodiment is a contact-type seal member in which the seal lip 56B is in a light contact state with the inner wall portion 38 of the seal groove 36. As a result, the sealability of the bearing can be ensured. In addition, the contact pressure between the seal lip 56B and the seal groove 36 can be maintained at a very small value in a preload state in which the ball bearing 10B with seal is incorporated in the motor, and mechanical loss during rotation of the bearing can be suppressed.

  Further, since the inner peripheral side edge of the seal lip 56B that contacts the seal groove 36 has an arc-shaped cross section, the seal lip 56B and the seal groove 36 reliably contact over the entire circumference even in a light contact state. Stable sealing performance is obtained.

(Fourth embodiment)
Next, a sealed ball bearing 10C according to a fourth embodiment will be described with reference to FIG. Parts having the same configuration as in the third embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Similarly, in the case of the present embodiment, the seal lip 56C and the seal groove 36 are separated in the axial direction and the radial direction before the preload is applied to the bearing. The distance between the seal lip 56C and the outer wall 39 inside the bearing of the seal groove 36 is set to a half of the axial internal clearance (nominal value) of the sealed ball bearing 10C.

  When preload is applied to the bearing in this state, the inner ring 30 is displaced outward (F1 direction in the figure), and the contact pressure between the outer wall portion 39 and the seal lip 56C decreases. Further, when the air pressure is applied from the outside of the bearing to the inside (F2 direction in the figure), the seal lip 56C is deflected in the F2 direction, and the seal lip 56C and the outer wall portion 39 of the seal groove 36 have a lower contact pressure. It will be in the light contact state which contacts with.

  According to the sealed ball bearing 10C of the present embodiment, the contact pressure between the seal lip 56C and the seal groove 36 is reduced by the synergistic effect of the preload and the pneumatic load. It can be further suppressed.

(Fifth embodiment)
Next, a ball bearing 10D with a seal according to a fifth embodiment will be described with reference to FIG. Parts having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Similar to the first embodiment, the ball bearing with seal 10D of the present embodiment includes an outer ring 20, an inner ring 30, a ball 15, a shield plate 40, and a seal member 50D.

  The seal member 50 </ b> D includes a cored bar 51 in which a thin metal plate is formed in an annular shape, and an annular shaped elastic part 53 formed of an elastic material such as a synthetic resin that covers the cored bar 51.

  The seal lip 56D is positioned in a seal groove 36 formed on the outer peripheral surface of the inner ring 30 in the nominal state. Further, the seal lip 56D does not contact the inner ring 30 (seal groove 36) in the nominal state, but in both the bearing non-rotation state after applying preload and the bearing rotation state when receiving air pressure, It is fixed to the outer ring 20 so as to be in contact with the seal groove 36 by elastic deformation.

  Here, the relationship between the inner diameter dimension φDc of the cored bar 51 of the seal member 50D (the inner diameter dimension of the inner peripheral side edge 54 of the cored bar 51) and the inner diameter dimension φDr of the seal lip 56D of the seal member 50D is 1.0. ≦ φDc / φDr ≦ 1.1 is satisfied.

  When the ratio of the inner diameter dimension φDc of the core metal 51 of the seal member 50D and the inner diameter dimension φDr of the seal lip 56D of the seal member 50D satisfies 1.0 or more and 1.1 or less, as described above, Rigidity increases, thereby reducing the amount of air leakage and ensuring the sealability of the bearing.

  In addition, the relationship between the inner diameter dimension φDc of the core metal 51 of the seal member 50D and the outer diameter dimension φDB of the inner ring outer peripheral surface 31 of the inner ring 30 satisfies φDc / φDB <1.0. Assuming that the ratio of the inner diameter of the core metal to the outer diameter of the inner ring (φDc / φDB) is less than 1.0, as described above, the flow of air passing through the bearing from the opposite side of the seal member 50D Therefore, deformation of the seal lip 56D can be suppressed. If the ratio of φDc / φDB is 1.0 or more, the seal lip 56D is easily deformed by the air pressure received by the seal member 50D, and the amount of air leakage increases.

  Also in the seal member 50D of the present embodiment, the contact pressure with respect to the seal groove 36 of the seal lip 56D is determined in consideration of the contact pressure when the bearing motor is incorporated.

  FIG. 10 shows an enlarged view of the main part of FIG. The seal lip 56D of the seal member 50D is disposed in a seal groove 36 formed on the inner ring outer peripheral surface 31 of the inner ring 30, and is separated from the seal groove 36 in the axial direction and the radial direction.

  FIG. 11 is a partially enlarged sectional view of the seal lip 56D. The seal lip 56D has an inner lip 56a1 that is an end of the inner peripheral edge 56a on the bearing inner side (direction toward the center of the bearing width), and an end on the outer side of the bearing (direction toward the bearing outer side along the axial direction). The outer lip 56a2 is a part. At least one of the inner lip 56a1 and the outer lip 56a2 has an arcuate cross section in the axial cross section of the bearing. In the illustrated example, the inner lip 56a1 has an arcuate cross section with a radius R1, and the outer lip 56a2 has an arcuate cross section with a radius R2.

  Here, as shown in FIG. 10, the axial distance between the inner lip 56a1 of the seal lip 56D and the inner wall portion 38 inside the bearing of the seal groove 36 is defined as Δdin. Further, the axial distance between the outer lip 56a2 of the seal lip 56D and the outer wall portion 39 outside the bearing of the seal groove 36 is represented by Δdout.

  In the nominal state, which is a state before applying preload, by attaching the seal member 50D to either of the axial ends of the bearing, the axial distance Δdin or Δdout on the side where the seal member 50D contacts the seal groove 36, or Both axial distances are set to half the axial internal clearance of the sealed ball bearing 10D.

  For example, in the case of mounting as shown in FIG. 12A, Δdin is set to half the length of the axial internal clearance. In the case of mounting as shown in FIG. 12B, Δdout is set to half the axial internal clearance.

  Next, the operation of the seal member 50D in a state where the sealed ball bearing 10D with the above configuration is incorporated in a bearing device such as a cleaner will be described.

  12A is an enlarged cross-sectional view of a main part showing a state of the seal member 50D when preload and air pressure are applied to the sealed ball bearing 10D shown in FIG. 10, and FIG. 12B is a seal of the sealed ball bearing 10D shown in FIG. 12A. It is a principal part expanded sectional view which shows the state of the sealing member 50D at the time of providing a member 50D in the bearing end part of an other side, and loading a preload and an air pressure.

  As shown in FIG. 12A, when a preload is applied to the inner ring 30 of the bearing in the direction Fa (the direction from the left end of the bearing toward the outside of the bearing in the figure), the inner ring 30 is displaced in the Fa direction. Then, the seal member 50 </ b> D enters a light contact state in which the inner lip 56 a 1 of the seal member 50 </ b> D contacts the inner wall portion 38 of the seal groove 36 with a low contact pressure from a non-contact state with the seal groove 36. In this light contact state, when air pressure is applied to the bearing in the Fb direction in the figure, the seal member 50D is pressed toward the outside of the bearing while receiving the air pressure and maintaining the contact state. Thereby, the seal member 50D is in a state in which the contact pressure with the seal groove 36 is further reduced.

  That is, the ball bearing 10D with a seal of this configuration has a clearance of a distance Δdin between the seal member 50D and the seal groove 36 shown in FIG. 10 before the preload is applied. For this reason, even if the inner ring 30 is displaced due to the preload, the seal member 50D does not bend because it does not contact the seal member 50D until the displacement amount of the inner ring 30 reaches the distance Δdin. Therefore, even if a preload is applied to the inner ring 30, not all of the preload is applied to the deformation of the seal member 50D. As a result, after the preload is applied, the seal member 50D is reduced in deformation to such an extent that it is slightly bent after coming into contact with the seal groove 36, and the contact pressure between the seal member 50D and the seal groove 36 is lowered.

  When air pressure is applied to the bearing, the seal member 50D is pressed toward the outside of the bearing, and the contact pressure between the seal member 50D and the seal groove 36 decreases. As a result, the frictional resistance between the seal member 50D and the seal groove 36 is synergistically reduced, and the dynamic friction loss of the bearing is reduced.

  Further, as shown in FIG. 12B, even when the seal member 50D is provided on the bearing end surface on the opposite side of the bearing, the dynamic friction loss of the bearing is reduced as described above. That is, when a preload in the Fa direction is applied to the inner ring 30 of the bearing, the seal member 50D has the clearance of the axial distance Δdout shown in FIG. It contacts the seal groove 36. When air pressure is applied in the Fb direction in this light contact state, the seal member 50D is pressed toward the inside of the bearing, so that the contact pressure between the seal member 50D and the seal groove 36 is synergistically reduced.

  Therefore, according to the sealed ball bearing 10D of this configuration, even if the seal member 50D is attached to any one of the bearing end surfaces of the bearing, the seal member 50D and the seal groove are caused by preload and air pressure load. The frictional resistance with 36 is reduced, and the dynamic friction loss of the bearing can be reduced.

  Further, the inner lip 56a1 and the outer lip 56a2 that are in contact with the seal groove 36 have an arcuate cross section in the axial cross section. For this reason, since the seal member 50D and the seal groove 36 are in contact with each other with a narrow contact area at the arc-shaped tip, the frictional resistance can be further reduced, and the dynamic friction loss of the bearing can be further reduced. Further, even in the light contact state as described above, the seal lip 56D and the seal groove 36 are in reliable contact over the entire circumference, and a stable sealing performance is obtained. As a result, the flow of air inside and outside the bearing can be blocked, and leakage of lubricant such as grease enclosed in the bearing to the outside of the bearing can be reliably prevented.

  The seal groove 36 is not limited to the above-described configuration, and may have another groove shape. FIG. 13 shows an enlarged cross-sectional view of the main part of the bearing in which the shape of the seal groove 36 is such that the inner wall portion 38 inside the bearing and the outer wall portion 39 outside the bearing have the same inclination angle.

  That is, in the bearing shown in FIG. 13, the inclination angle of the inner wall 38 on the inner side of the bearing with respect to the radial direction of the inner ring 30 is φ1, and the inclination angle of the outer wall 39 on the outer side of the bearing with respect to the radial direction of the inner ring 30 is φ2. In this case, the inclination angle φ1 and the inclination angle φ2 are equal.

  In this case, the symmetry of the seal groove 36 with respect to the seal member 50D is improved, and the seal member 50D can be easily and accurately disposed at a position where the axial distances Δdin and Δdout are equal. Further, the axial distance between the seal groove and the seal lip 56D does not change even if the seal member 50D is attached to either end of the bearing in the axial direction. Therefore, the compatibility of the seal member 50D can be further improved. This also makes it possible to obtain the above-described bearing performance more stably.

  According to the sealed ball bearings 10, 10 </ b> A, 10 </ b> A <b> 1, 10 </ b> B, 10 </ b> C, 10 </ b> D of each embodiment described above, ensuring the sealability of the bearing and reducing mechanical loss between the seal lip of the seal member and the inner ring. And both. Further, the contact pressure between the seal member and the seal groove can be kept low regardless of the arrangement position of the seal member. Furthermore, it is not necessary to selectively attach different seal members to the bearing according to the pressure load direction, the bearing manufacturing process is simplified, and the cost can be reduced.

  When this sealed ball bearing is applied to equipment such as a cleaner, the efficiency of the motor is improved because the mechanical loss of the bearing is small, and the suction efficiency of the cleaner is improved due to the high sealing performance inside the bearing. improves. As a result, variation in the suction work rate of the cleaner can be prevented, and energy saving can be secured.

  In order to confirm the effect of the present invention, an experiment was conducted using a test apparatus capable of applying air pressure to a bearing to be evaluated while rotating a motor incorporating the bearing to be evaluated. Here, the ball bearings with seals according to the first embodiment and the second embodiment shown in FIGS. 1 and 3 are referred to as Examples 1 and 2, respectively. Further, the ball bearings with seals according to the third embodiment and the fourth embodiment shown in FIGS. 5 and 8 are referred to as Examples 3 and 4, respectively. Further, the ball bearing with seal according to the fifth embodiment shown in FIG.

  Regarding the sealed ball bearings of Examples 1 to 5 and the sealed ball bearings of Conventional Examples 1 to 3 shown in FIGS. 16 to 19, the sealing performance and the power consumption of the motor, that is, the dynamic friction loss of the bearing were evaluated. . 14 and 15 show the results.

  The result shown in FIG. 14 is a graph comparing Examples 1 to 4 and Conventional Examples 1 to 3 with an average value of five measurement results. Since the seal members of the conventional examples 1 and 2 are contact-type seal members, the motor current consumption value is high due to friction loss at the contact portion when the load air pressure (load pressure) is low. In addition, as the load air pressure increases, the flow of air passing through the inside of the bearing is generated, so that the contact pressure of the seal lip with the inner ring gradually decreases, the friction loss decreases, and the motor current consumption value decreases. However, at the same time, air passes through the inside of the bearing and leaks to the side opposite to the air pressure application side, and the sealing performance of the bearing is reduced.

  Since the seal member of Conventional Example 3 is a non-contact type, the dynamic friction loss of the bearing is stably low, and the motor current consumption value is stable. However, immediately after the air pressure is applied, the air passes through the bearing and leaks to the side opposite to the air pressure application side, and the amount of air leakage increases as the load air pressure increases.

  On the other hand, since the seal members of Examples 1 and 2 are non-contact type seal members, the dynamic friction loss of the bearing is stably suppressed to a low value, and the motor current consumption value is stable. Furthermore, by improving the rigidity of the seal lip, the force against the flow of air passing through the inside of the bearing is increased, and an increase in the amount of air leakage due to an increase in load air pressure is suppressed.

  Thus, in the sealed ball bearings of Examples 1 and 2, air leakage occurred in a state where the load air pressure was lower than that of the sealed ball bearings of Conventional Examples 1 and 2, but the load air pressure increased. The increase in the amount of air leakage accompanying this is moderate. From this, when the ball bearing with seal of Examples 1 and 2 is used in a cleaner motor, it is possible to suppress fluctuations in leakage pressure with respect to fluctuations in load air pressure, and to prevent variations in cleaner suction performance. In the ball bearings with seals of Examples 1 and 2, the motor power consumption is stably low regardless of the load air pressure. Therefore, according to the sealed ball bearing of this configuration, it can be seen that both reduction of mechanical loss during rotation of the bearing and securing of the sealability of the bearing can be realized.

  In addition, since the seal members of Examples 3 and 4 are contact type, the motor consumption current value representing the bearing dynamic friction loss is lower than that of the non-contact type seal member of Conventional Example 3 when the load air pressure is low. Slightly higher. However, in Examples 3 and 4, it can be seen that the dynamic friction loss can be reduced by setting the contact pressure of the seal lip to a minute amount as compared with the contact-type seal members of Conventional Examples 1 and 2. Further, in Examples 3 and 4, since the rigidity of the seal lip is improved, the force against the flow of air passing through the inside of the bearing is increased, and an increase in the amount of air leakage due to an increase in load pressure is suppressed. It turns out that it is possible.

  Thus, the sealed ball bearings of Examples 3 and 4 have the effect that the motor current consumption, that is, the motor power consumption is low when the load air pressure is low, as compared with the sealed ball bearings of Conventional Examples 1 and 2. Was confirmed. Moreover, the sealing member in Examples 3 and 4 has confirmed the effect that the sealing performance of the bearing is improved as compared with the non-contact type sealing member shown in Conventional Example 3. Therefore, according to the ball bearing with seal of each example, it can be understood that both reduction of mechanical loss and sealing performance of the bearing can be realized.

  The result shown in FIG. 15 is a graph comparing Example 5 and Conventional Examples 1 to 3 with an average value of five measurement results.

  Compared to the above-described Conventional Example 3, the seal member of Example 5 is a contact-type seal member, but the dynamic friction loss of the bearing is stably kept low, and the motor current consumption value is stable. Furthermore, by improving the rigidity of the seal lip, the force against the flow of air passing through the inside of the bearing is increased, and an increase in the amount of air leakage due to an increase in load air pressure is suppressed.

  As described above, the sealed ball bearing of Example 5 hardly causes air leakage when the load air pressure is low as compared with the sealed ball bearings of Conventional Examples 1 and 2, and the load air pressure increases. The increase in air leakage is gradual. From this, when the ball bearing 10 with a seal is used for the motor of the cleaner, the fluctuation of the leakage pressure with respect to the fluctuation of the load air pressure can be suppressed, so that the variation in the suction performance of the cleaner can be prevented. In the ball bearing with seal of Example 5, the motor power consumption is stably low regardless of the load air pressure. Therefore, according to the sealed ball bearing of this configuration, it can be seen that both reduction of mechanical loss during rotation of the bearing and sealing performance of the bearing can be realized.

  The present invention is not limited to the above-described embodiments, and appropriate modifications and improvements can be made. For example, in the ball bearing with seal according to each of the above-described embodiments, the shield plate 40 is formed of a thin metal plate. However, the shield plate 40 is formed by coating a metal core with an elastic material such as rubber or synthetic resin. And you may form so that the whole may become an annular | circular shape. Further, the elastic part of the seal member may be formed of rubber or the like. Furthermore, the ball bearing with seal of the present invention is not limited to an angular ball bearing, and may be another rolling bearing such as a cylindrical roller bearing.

  The present invention is applicable to, for example, a bearing used in a cleaner motor.

  This application is based on a Japanese patent application filed on Feb. 17, 2014 (Japanese Patent Application No. 2014-27740) and a Japanese patent application filed on March 24, 2014 (Japanese Patent Application No. 2014-59995). The contents are incorporated herein by reference.

10, 10A, 10A1, 10B, 10C, 10D Sealed ball bearing 15 Ball 20 Outer ring 22 Outer ring raceway surface 30 Inner ring 31 Inner ring outer peripheral surface 32 Inner ring raceway surface 36 Seal grooves 50, 50A, 50A1, 50B, 50C, 50D Seal member 51 Core metal 56, 56A, 56A1, 56B, 56C, 56D Seal lip 56a Inner peripheral edge 56a1 Inner lip 56a2 Outer lip

Claims (8)

A plurality of outer rings having an outer ring raceway surface formed on an inner peripheral surface, an inner ring having an outer ring raceway surface formed on an outer peripheral surface, and a plurality of rollers arranged in a circumferential direction so as to be freely rollable between the outer ring raceway surface and the inner ring raceway surface. A ball bearing with a seal comprising a ball and a seal member fixed to the inner peripheral surface of the outer ring,
The seal member comprises an annular cored bar and an annular elastic part that covers the cored bar,
The inner diameter φDc of the core metal of the seal member and the inner diameter φDr of the elastic portion satisfy 1.0 ≦ φDc / φDr ≦ 1.1,
A sealed ball bearing, wherein an inner diameter φDc of the cored bar of the seal member and an outer diameter φDB of the inner ring satisfy φDc / φDB <1.0. The inner peripheral edge of the elastic part is located in a seal groove formed on the outer peripheral surface of the inner ring,
2. The ball bearing with seal according to claim 1, wherein an axial distance Δd between the inner peripheral edge of the elastic portion and the seal groove is half the axial internal clearance. The elastic portion is located in a seal groove formed on the outer peripheral surface of the inner ring;
2. The ball bearing with seal according to claim 1, wherein the seal member is fixed to the outer ring in a non-contact state with the seal groove at all times.   The ball bearing with seal according to claim 2, wherein the seal member is fixed to the outer ring so as to be in contact with the seal groove.   The ball bearing with seal according to claim 4, wherein the inner peripheral edge of the elastic portion contacting the seal groove has an arc-shaped cross section in an axial cross section.   The elastic portion has a bearing inner inner lip and a bearing outer outer lip disposed in a seal groove formed in the outer peripheral surface of the inner ring, and the inner lip and the outer lip are 2. The ball bearing with seal according to claim 1, wherein each of the ball bearings has an arcuate cross section in an axial cross section.   At least one of an axial distance between the inner lip and the inner wall of the seal groove inside the bearing, and an axial distance between the outer lip and the outer wall of the seal groove outside the bearing. 7. One of the ball bearings with a seal according to claim 6, wherein one is half the axial internal clearance before the preload is applied.   The ball with a seal according to claim 6 or 7, wherein the inner wall portion inside the bearing and the outer wall portion outside the bearing in the seal groove have the same inclination angle with respect to the radial direction of the inner ring. bearing.

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