JP4917779B2 - Coreless seals and rolling bearings - Google Patents

Description

  The present invention relates to a coreless seal and a rolling bearing, and more particularly to a coreless seal and a rolling bearing used at a low temperature.

  When the rotating shaft is attached to the inner diameter hole of the outer member such as the housing, a seal may be provided to prevent fluid leakage between the outer diameter surface of the rotating shaft and the inner diameter surface of the inner diameter hole.

  FIG. 6 is a cross-sectional view showing a part of a conventional seal with a cored bar in a free state. In FIG. 6, the outer diameter surface of the rotating shaft (not shown) located on the inner diameter side of the cored seal is indicated by a two-dot chain line. In this specification, the free state means a state in which the rotary shaft and the outer member are not incorporated. Referring to FIG. 6, the cored seal 101 includes an annular member 102 having elasticity and a cored bar 103 made of a metal material. By providing the cored bar 103 with the cored bar seal 101, rigidity can be ensured, and the cored seal 101 does not thermally contract at a low temperature.

  The outer diameter X of the seal 101 with the cored bar is a dimension obtained by adding a fastening allowance 2Y to the inner diameter C of the inner diameter hole to be attached. By providing the tightening allowance Y, the outer diameter surface 104 of the seal 101 with the core metal can be nipped and contacted with the inner diameter surface of the inner diameter hole when attached to the inner diameter hole. Leakage between the attached seal 101 and the inner diameter hole can be prevented. Further, the cored seal 101 is provided with a lip portion 105 protruding toward the inner diameter side. The inner diameter dimension Z of the lip portion 105 is configured to be smaller than the outer diameter dimension E of the rotating shaft. In this way, when attached to the rotating shaft, the lip portion 105 nips and contacts the outer diameter surface of the rotating shaft with an appropriate pressure to prevent leakage between the cored seal 101 and the rotating shaft. be able to.

  Next, the case where the above-described cored seal 101 is incorporated into a shell-type roller bearing will be described. FIG. 7 is a cross-sectional view showing a state in which the seal 101 with the cored bar is assembled into the shell roller bearing 111, and the seal 101 with the cored bar in a free state before being assembled is indicated by a dotted line. Referring to FIG. 7, shell-shaped roller bearing 111 includes shell-shaped outer ring 112, a plurality of rollers 113, a cage 114, and a cored seal 101. The cored seal 101 is disposed and attached between a shell-shaped outer ring 112 as an outer member and a rotating shaft. Here, since the inner diameter surface 115 of the shell-shaped outer ring 112, the outer diameter surface 104 of the cored seal 101, the outer diameter surface of the rotating shaft, and the lip portion 105 are nipped with an appropriate pressure, the shell-shaped outer ring 112 rotates with the shell-shaped outer ring 112. There is no leakage between the shaft.

  However, since such a cored seal 101 is composed of a plurality of members, the cost increases. Further, since the cored seal 101 has rigidity, it is difficult to remove it after being incorporated into the shell-type roller bearing.

  For such a problem, a technique related to a coreless seal that does not have a cored bar as a constituent material is disclosed in Japanese Patent Application Laid-Open No. 2004-293618 (Patent Document 1). According to Patent Document 1, since the coreless seal is composed of only an elastic member, the cost is low, and it is easy to remove even after being assembled.

Here, a coreless seal without a cored bar will be described. FIG. 8 is a sectional view showing a part of the coreless seal. Referring to FIG. 8, the coreless seal 106 is composed of only an annular member 107 having elasticity. About the dimension of the seal | sticker 106 without a metal core, it is the same as that of the above-mentioned seal with a metal core, and the outer diameter dimension X is a dimension obtained by adding a tightening margin 2Y to the inner diameter dimension C of the inner diameter hole. The dimension Z is configured to be smaller than the outer diameter dimension E of the rotating shaft.
Japanese Unexamined Patent Publication No. 2004-293618 (paragraph numbers 0018 to 0026, FIG. 2)

  As described above, the coreless seal composed only of the elastic member prevents leakage between the outer member and the rotating shaft when it is placed at a room temperature, as described above. be able to. However, at a low temperature, the coreless seal 106 does not have the dimensional relationship described above, and thus cannot prevent leakage therebetween.

  This will be described with reference to FIG. FIG. 9 is a part of a cross-sectional view showing a state where the coreless seal at low temperature is incorporated in the shell-type roller bearing 111. The coreless seal 106 at normal temperature is indicated by a dotted line. Referring to FIG. 9, since the coreless seal 106 contracts in the direction indicated by the arrow W at a low temperature, the outer diameter dimension changes from X to X ′, and the inner diameter surface of the shell-shaped outer ring 112 which is the outer member It becomes smaller than the inner diameter dimension C of 115. Then, when incorporated in the shell-type roller bearing 111, the inner diameter surface 115 of the shell-shaped outer ring 112 and the outer diameter surface 109 of the coreless seal 106 do not nip, and a gap V is generated between them. If there is such a gap V, leakage between the shell-shaped outer ring 112 and the rotating shaft will occur.

  Further, since the inner diameter side lip portion 108 contracts in the direction indicated by the arrow W, the inner diameter dimension of the lip portion 108 is changed from Z to Z ′, and the lip portion 108 is located on the inner diameter side. As a result, the amount of nip increases, the amount of biting with the rotating shaft increases, and at the time of rotation, the rotating shaft and the coreless seal 106 rotate together, which may impair the sealing performance.

  An object of the present invention is to provide a coreless seal and a rolling bearing having high sealing performance even at low temperatures.

  The coreless seal according to the present invention is a coreless seal that is disposed between a rotating shaft and an outer member having an inner diameter surface facing the outer diameter surface of the rotating shaft with a space therebetween, and prevents fluid leakage. is there. Here, the outer diameter of the coreless seal has an allowance that takes into account the amount of heat shrinkage.

  With this configuration, even if the coreless seal disposed between the rotating shaft and the outer member with a gap is thermally shrunk at a low temperature and the outer diameter is reduced, the outer surface of the coreless seal is removed. Since the diameter dimension is larger than the inner diameter dimension of the inner diameter surface of the outer member, there is no gap between the outer diameter surface of the coreless seal and the inner diameter surface of the outer member. Therefore, even at a low temperature, the outer diameter surface of the coreless seal and the inner diameter surface of the outer member can be nipped with an appropriate pressure, and the sealing performance is high.

  Preferably, if the dimension in the radial direction of the interference allowance including the amount of heat shrinkage is A and the outer diameter dimension of the coreless seal in a free state at room temperature is B, 0.005B ≦ A ≦ 0.030B A relationship is established. If A is set to 0.005B or more, it is possible to ensure a minimum tightening allowance considering the amount of heat shrinkage at a low temperature. Further, when A is 0.030B or less, the size of the tightening allowance is not increased more than necessary, so that it can be easily incorporated into the outer member.

  More preferably, if the inner diameter dimension of the outer member is C, a relationship of 0.950B ≦ C ≦ 0.985B is established. By doing so, it is possible to take an optimum dimension in the dimensional relationship with the outer member that hardly needs to consider heat shrinkage.

  More preferably, the relationship of E <D <E + 2A is established, where D is the inner diameter dimension of the coreless seal in a free state at room temperature and E is the outer diameter dimension of the rotating shaft. By doing so, the inner diameter dimension of the lip portion can be made smaller than the outer diameter dimension of the rotating shaft when assembled at normal temperature. Further, even at low temperatures, it is possible to suppress biting of the coreless seal on the rotating shaft.

  In another aspect of the present invention, the rolling bearing has any of the above coreless seals. By doing so, it is possible to provide a rolling bearing having high sealing performance even at low temperatures.

  According to the present invention, even when the coreless seal is thermally contracted at a low temperature and the outer diameter is reduced, the outer diameter of the coreless seal is larger than the inner diameter of the inner diameter surface of the outer member. There is no gap between the outer diameter surface of the coreless seal and the inner diameter surface of the outer member.

  As a result, even at low temperatures, the outer diameter surface of the coreless seal and the inner diameter surface of the outer member can be nipped with an appropriate pressure, and the sealing performance is high.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view showing a free state at normal temperature of the coreless seal 11 according to one embodiment of the present invention. Referring to FIG. 2, the coreless seal 11 is composed of only an annular member 12 having elasticity. The outer diameter B of the coreless seal 11 is a dimension obtained by adding a tightening allowance 2A in consideration of the amount of heat shrinkage to the inner diameter C of the outer member. Moreover, the inner diameter dimension D of the coreless seal 11 where the lip portion 14 protruding toward the inner diameter side is located is configured to be slightly larger than the outer diameter dimension E of the rotating shaft.

  Here, in the dimensional relationship described above, 0.005B ≦ A ≦ 0.030B is preferable. When A is 0.005B or more, a minimum fastening allowance at a low temperature can be secured. Further, when A is 0.030B or less, the size of the tightening allowance is not increased more than necessary, so that incorporation into the outer member is facilitated. Moreover, it is good also as 0.950B <= C <= 0.985B. By doing so, the outer diameter B can be defined in relation to the inner diameter C of the outer member that hardly needs to consider heat shrinkage. Furthermore, it is good also as E <D <E + 2A. If D is greater than E, the amount of biting with the rotating shaft when assembled can be made appropriate in consideration of thermal shrinkage at low temperatures. If D is smaller than E + 2A, the lip portion can bite against the rotating shaft when assembled.

  Next, a state in which the above-described coreless seal 11 is disposed between the spaced apart rotating shaft and the outer member will be described. FIG. 1 is a sectional view showing a part of a shell-type roller bearing when a shell-type outer ring of a shell-type roller bearing is used as an outer member. In FIG. 1, the outer shape of the coreless seal 11 in a free state at a low temperature is indicated by a dotted line, and the outer shape of the coreless seal 11 in a free state at a normal temperature is indicated by a one-dot chain line. Referring to FIG. 1, shell-shaped roller bearing 21 supports a rotating shaft (not shown) located on the inner diameter side thereof. The shell type roller bearing 21 includes a shell type outer ring 22 having a raceway surface on an inner diameter surface 25, a plurality of rollers 23, a cage 24 that holds the plurality of rollers 23, and a coreless seal 11. The shell-shaped outer ring 22 has a flange portion 26 whose edge bent portion extends radially inward. The coreless seal 11 that is a constituent member of the shell-type roller bearing 21 is disposed and incorporated between the rotating shaft and the shell-shaped outer ring 22. The position of the coreless seal 11 in the axial direction is between the cage 24 and the flange portion 26.

  First, the built-in state at normal temperature will be described. The outer diameter dimension B of the coreless seal 11 is a dimension obtained by adding a fastening allowance 2A to the inner diameter dimension C of the inner diameter surface 25 of the shell-shaped outer ring 22. Therefore, on the outer diameter side, the inner diameter surface 25 of the shell-shaped outer ring 22 and the outer diameter surface 13 of the coreless seal 11 can be nipped with an appropriate pressure. On the inner diameter side, the inner diameter dimension D of the lip portion 14 is configured to be larger than the outer diameter dimension E of the rotating shaft in a free state. However, when incorporated between the shell-shaped outer ring 22 and the rotary shaft, the coreless seal 11 contracts. Accordingly, since the inner diameter dimension when incorporated between the rotating shaft and the shell-shaped outer ring 22 is smaller than the outer diameter dimension E of the rotating shaft, the lip portion 14 can be nipped from the rotating shaft with an appropriate pressure. it can.

  Next, an assembled state at a low temperature will be described. On the outer diameter side, the annular member 12 contracts in the direction of the arrow W in FIG. 1, so the outer diameter dimension of the coreless seal 11 decreases from B to B ′. However, since the outer diameter dimension B is provided with a tightening allowance A that takes into account the amount of heat shrinkage in advance, the coreless seal 11 has a tightening allowance A ′ in the outer diameter dimension B ′ even after shrinkage. Have. Therefore, even at a low temperature, the nip can be performed with an appropriate pressure without generating a gap between the inner diameter surface 25 of the shell-shaped outer ring 22 and the outer diameter surface 13 of the coreless seal 11. On the inner diameter side, the inner diameter dimension of the lip portion 14 also decreases from D to D '. However, it is only slightly smaller than the outer diameter dimension E of the rotating shaft, and can be nipped with the outer diameter surface 27 of the rotating shaft with an appropriate pressure without increasing the amount of biting on the rotating shaft.

  As described above, even at low temperatures, the coreless seal can nip the outer diameter surface and the inner diameter surface with an appropriate pressure, and has a high sealing performance between the rotating shaft and the shell roller bearing.

  The coreless seal incorporated in such a shell-type roller bearing may be incorporated on one flange side of the shell-shaped outer ring, or may be incorporated on both flange sides. FIG. 3 is a cross-sectional view of a shell roller bearing when a coreless seal is incorporated on one flange side. Referring to FIG. 3, shell-shaped roller bearing 31 incorporates a coreless seal 34 on one flange 33 side of shell-shaped outer ring 32. By carrying out like this, the leak by the side of one collar 33 can be prevented. FIG. 4 is a cross-sectional view of a shell-type roller bearing when a coreless seal is incorporated on both flange sides. Referring to FIG. 4, shell-type roller bearing 36 incorporates coreless seals 39 a and 39 b on both flange portions 38 a and 38 b side of shell-shaped outer ring 37. By doing so, it is possible to prevent leakage on the side of both flanges 38a, 38b.

  In the above-described embodiment, the shell-shaped outer ring of the shell-type roller bearing is used as the outer member, and the coreless seal is one of the constituent members of the shell-shaped roller bearing. Other members may be used and may not be one of the constituent members of the roller bearing.

  FIG. 5 is a cross-sectional view illustrating a state in which the coreless seal is disposed between the outer member housing and the rotation shaft. Referring to FIG. 5, a ball bearing 43 is disposed between an inner diameter hole 42 provided in the housing 41 and a rotation shaft (not shown), and supports the rotation shaft on the inner diameter side. The ball bearing 43 includes a ball 47 that is a rolling element, an inner ring 48, and an outer ring 46. The outer diameter surface 51 of the outer ring 46 and the inner diameter surface 49 of the inner diameter hole 42 are in contact with each other, and the inner diameter surface 52 of the inner ring 48 is in contact with the outer diameter surface of the rotating shaft. In addition, a cap portion 45 is provided on the outer side in the axial direction of the ball bearing 43 on the opening end side of the inner diameter hole 42 in order to prevent foreign matters from entering from the outside.

  Here, the coreless seal 44 is disposed between the rotating shaft and the housing 41. The axial position is between the ball bearing 43 and the cap portion 45. Here, even when the temperature is low, the coreless seal 44 has a tightening allowance in consideration of the amount of heat shrinkage, so that the inner diameter surface 49 of the inner diameter hole 42 and the outer diameter surface 50 of the coreless seal 44 are separated. Can be nipped with moderate pressure. Further, the outer diameter surface of the rotating shaft and the lip portion of the coreless seal 44 do not bite the rotating shaft. By doing so, it is possible to prevent leakage between the spaced apart rotating shaft and the housing.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  Since the coreless seal and rolling bearing according to the present invention have high sealing performance even at low temperatures, they are effectively used for the coreless seal and rolling bearing used in a low temperature environment.

It is sectional drawing at the time of incorporating the coreless seal | sticker which concerns on one Embodiment of this invention in a shell type roller bearing. It is sectional drawing which shows a part of seal | sticker without a metal core which concerns on one Embodiment of this invention in the free state at the normal temperature. It is sectional drawing of the shell type roller bearing which incorporated the coreless seal | sticker in the one collar part side. It is sectional drawing of the shell-type roller bearing which incorporated the coreless seal | sticker in both the collar part side. It is sectional drawing at the time of arrange | positioning the coreless seal | sticker on the outer side of a ball bearing. It is sectional drawing which shows a part of conventional seal | sticker with a metal core. It is sectional drawing which shows the state which integrated the seal with a metal core in the past in the shell type roller bearing. It is sectional drawing which shows a part of conventional coreless seal | sticker. It is sectional drawing which shows the state which incorporated the coreless seal | sticker in the time of the conventional low temperature in the shell type roller bearing.

Explanation of symbols

  11, 34, 39a, 39b, 44 Coreless seal, 12 Annular member, 13, 27, 50, 51 Outer diameter surface, 14 Lip part, 21, 31, 36 Shell type roller bearing, 22, 32, 37 Shell type Outer ring, 23 rollers, 24 Cage, 25, 49, 52 Inner diameter surface, 26, 33, 38a, 38b Hook, 41 Housing, 42 Inner hole, 43 Ball bearing, 45 Cap part, 46 Outer ring, 47 Ball, 48 Inner ring .

Claims (5)

A rotating shaft, comprising a radially inner surface which faces spaced radially outer surface of said rotary shaft, said outer member between the outer member having a flange portion thereof crimp extends radially inward A coreless seal that is arranged to be incorporated on the inner diameter side of the core and prevents fluid leakage,
The coreless seal without outer diameter and inner diameter of the coreless seal has an allowance considering the amount of heat shrinkage as a whole dimension in the radial direction. When the dimension in the radial direction of the tightening allowance considering the amount of heat shrinkage is A, and the outer diameter dimension of the coreless seal in a free state at room temperature is B,
The coreless seal according to claim 1, wherein a relationship of 0.005B ≦ A ≦ 0.030B is established. When the inner diameter dimension of the outer member is C,
The coreless seal according to claim 1, wherein a relationship of 0.950B ≦ C ≦ 0.985B is established. If the inner diameter dimension of the coreless seal in a free state at room temperature is D and the outer diameter dimension of the rotating shaft is E,
The coreless seal according to any one of claims 1 to 3, wherein a relationship of E <D <E + 2A is established. A rolling bearing having the coreless seal according to claim 1.

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