JP2006226437A - Conductive bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive bearing having small electric resistance and capable of allowing electricity generated by static or various causes to smoothly and surely escape (to the ground) without being influenced by the formation of an insulation film in a high-temperature environment. <P>SOLUTION: This conductive bearing 6 is provided with: bearing rings (an inner ring 8 and an outer ring 10) relatively rotatably arranged oppositely to each other; a plurality of rolling elements 12 arranged so as to be rollable between the bearing rings; and sealing plates 22 mounted between the bearing rings on both sides of the rolling elements. The bearing is filled with conductive grease in its inside. The respective bearing rings are fixed to predetermined external structures (a shaft 4 and a housing 20), and at least either of the bearing rings is provided with a current-carrying grounding mechanism for grounding the ring to an external structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing used for a heat roll and a pressure roll of office equipment represented by a copying machine and a printer, for example, and particularly relates to a conductive bearing having a low electrical resistance that exhibits an excellent energization / grounding function in a high temperature environment .

  2. Description of the Related Art Conventionally, a conductive bearing in which conductive grease is sealed is known as a bearing used for a heat roll or a pressure roll of a copying machine or a printer (for example, Patent Document 1). For example, FIG. 3 shows a configuration example of the conductive bearing 6 that rotatably supports the shaft 4 protruding from the heat roll 2. The conductive bearing 6 includes an inner ring 8 and an outer ring 10 that are opposed to each other so as to be relatively rotatable, a plurality of rolling elements 12 that are arranged so as to be able to roll between the inner and outer rings 8 and 10, and one each rolling element 12. The inner ring 8 has an inner ring inner peripheral surface 8 s fixed to the shaft 4 via a fixing ring 16, and the outer ring 10 has an outer ring outer peripheral surface 10 s fixed to the retaining ring 18. Via the housing 20.

  Further, the conductive bearing 6 is provided with sealing plates 22 on both sides of the inner and outer rings 8 and 10 and contains a conductive lubricant (for example, base oil, thickener, conductive carbon black, etc.). Conductive grease) is enclosed. According to such a conductive bearing 6, static electricity charged on the heat roll 2 (shaft 4) is released (grounded) from the inner ring 8 to the housing 20 via the conductive grease and the outer ring 10, for example, at the time of toner fixing. In this case, the printing is prevented from being blurred or disturbed by static electricity. In addition, although a seal | sticker and a shield can be applied as the sealing board 22, a shield is assumed here as an example.

By the way, since the heat roll 2 as described above reaches a high temperature of about 200 ° C. at the time of fixing the toner, for example, the surface of the conductive bearing 6 (for example, the inner ring inner peripheral surface 8s or the outer ring outer peripheral surface) under such a high temperature environment. 10s) may be oxidized to produce an insulating film. In this case, in the conventional conductive bearing 6, the contact portion between the shaft 4 and the inner ring inner peripheral surface 8 s and the contact portion between the outer ring outer peripheral surface 10 s and the housing 20 are used as they are as ground contacts. If an insulating film is formed on the surface 8s or the outer peripheral surface 10s of the outer ring, the electrical resistance increases due to a contact failure, and as a result, the static electricity charged on the heat roll 2 (shaft 4) is smoothly and reliably released (grounded). May become difficult.
JP 2004-162909 A

  The present invention has been made to solve such problems, and its purpose is to smoothly and reliably generate electricity generated by static electricity and various factors without being affected by the formation of an insulating film in a high temperature environment. An object of the present invention is to provide a conductive bearing having a low electrical resistance that can be released (grounded).

  In order to achieve such an object, the present invention provides a bearing ring disposed so as to be relatively rotatable, a plurality of rolling elements arranged so as to be able to roll between the bearing rings, and tracks on both sides of these rolling elements. A conductive plate having a sealing plate provided between the rings, in which conductive grease is sealed, and each bearing ring is fixed to a predetermined external configuration, and at least one of the bearing rings An energization ground mechanism for grounding the external configuration is provided.

In the present invention, the following configuration can be applied as the energization grounding mechanism.
The energization ground mechanism includes a conductive ground member embedded in the raceway, and the conductive ground member is grounded to an external configuration via a conductive wire. The energization grounding mechanism includes a conductive ground member partially embedded in the raceway, and a part of the conductive ground member is directly grounded to the external configuration. Further, the energization grounding mechanism includes a conductive earth member whose base end is embedded in the raceway ring, and the conductive earth member is grounded by fitting its distal end into an external configuration. Furthermore, the energization grounding mechanism includes a conductive grounding member that can be directly grounded to the external configuration, and a biasing unit that biases the conductive grounding member toward the external configuration and directly grounds the conductive grounding member.

  According to the present invention, it is possible to smoothly and surely escape (ground) electricity generated by static electricity and various factors without being affected by the generation of an insulating film in a high-temperature environment, and has a low electrical resistance. A bearing can be realized.

  Hereinafter, the conductive bearing of the present invention will be described with reference to the accompanying drawings. As the conductive bearing of the present invention, for example, a radial bearing or a thrust bearing in which balls or rollers are incorporated as rolling elements can be applied, but here a ball (rolling element 12: see FIG. 3) is incorporated as an example. A radial bearing is assumed. In this case, in the following description, the same components as those of the above-described conductive bearing (FIG. 3) are denoted by the same reference numerals, the description thereof is omitted, and only different components are described. In the following drawings, the conductive lubricant is not particularly shown, but the conductive lubricant is sealed in the space region of the inner and outer rings 8 and 10 in a state where leakage is prevented by the pair of sealing plates 22. .

  FIG. 1A shows a configuration example of the conductive bearing 6 according to the first embodiment. In the conductive bearing 6, each raceway ring (the inner ring 8 and the outer ring 10) is a predetermined external part. While being fixed to the configuration, at least one of the races is provided with an energization grounding mechanism for grounding to the external configuration. Here, the external configuration corresponds to the shaft 4 to which the inner ring inner peripheral surface 8s of the inner ring 8 is fixed and the housing 20 to which the outer ring outer peripheral surface 10s of the outer ring 10 is fixed.

In this case, the energization grounding mechanism may be provided in at least one of the inner ring 8 and the outer ring 10, but in the present embodiment, as an example, the energization grounding mechanism is provided in both the inner ring 8 and the outer ring 10, respectively. Conductive grounding members 24a and 24b embedded in the inner ring 8 and the outer ring 10 are provided, and the conductive grounding members 24a and 24b are grounded to the external configuration (the shaft 4 and the housing 20) via the conductive wires 26a and 26b. .
As the material of the conductive ground members 24a and 24b and the conductive wires 26a and 26b, a conductive material having a low electrical resistance (for example, carbon steel, aluminum alloy, stainless steel, copper alloy, etc.) may be applied. In this case, the conductive wires 26a and 26b are preferably covered with an insulating material (not shown) for preventing oxidation (preventing rust). Further, as a material of the conductive bearing 6 (for example, the inner ring 8 and the outer ring 10), a conductive material such as high carbon chrome bearing steel or stainless steel may be applied.

Here, an example of a method of embedding the conductive ground members 24a and 24b in the inner ring 8 and the outer ring 10 will be described.
The conductive ground members 24a and 24b can be embedded in the inner ring 8 and the outer ring 10 by being pushed into grooves 8g and 10g formed in the inner ring 8 and the outer ring 10, respectively. In this case, the grooves 8g and 10g can be set to an arbitrary shape such as a cylindrical shape or a rectangular shape, and the conductive ground members 24a and 24b can be configured in a shape corresponding to the set groove shape. For example, in the case of cylindrical grooves 8g and 10g, spherical conductive earth members 24a and 24b having an outer diameter slightly larger than the inner diameter of the cylindrical grooves 8g and 10g are prepared, and such conductive earth members 24a, By pushing the 24b into the grooves 8g and 10g, the conductive ground members 24a and 24b can be firmly embedded in the grooves 8g and 10g.

  Further, it is preferable to set the number of conductive ground members 24a and 24b to be embedded at a predetermined interval (for example, four locations at equal intervals) along the circumferential direction of the inner ring 8 and the outer ring 10. In this case, a number of grooves 8g and 10g corresponding to the set number of embedded holes are formed intermittently at predetermined intervals along the circumferential direction of the inner ring 8 and the outer ring 10, and a conductive ground is provided in each of the grooves 8g and 10g. After embedding the members 24a and 24b, the conductive wires 26a and 26b may be extended from the conductive ground members 24a and 24b to the external structure (the shaft 4 and the housing 20) and grounded. As a grounding method, the extended ends of the conductive wires 26a and 26b may be brazed to the external configuration (the shaft 4 and the housing 20) with, for example, solder (solder) 28.

  Further, as described above, instead of embedding the conductive ground members 24a and 24b at predetermined intervals, for example, they may be embedded continuously along the circumferential direction of the inner ring 8 and the outer ring 10. In this case, the grooves 8g and 10g are continuously formed along the circumferential direction of the inner ring 8 and the outer ring 10, and the long conductive ground members 24a and 24b are continuously pushed into the grooves 8g and 10g. . Then, one or a plurality of conducting wires 26a, 26b may be extended from any location to the external configuration (shaft 4, housing 20) and grounded. By thus applying the long conductive ground members 24a and 24b, the degree of freedom of the grounding positions of the conductors 26a and 26b can be improved.

  As described above, according to the first embodiment, the conductive ground members 24a and 24b embedded in the race rings (the inner ring 8 and the outer ring 10) are grounded to the external configuration (the shaft 4 and the housing 20) via the conductive wires 26a and 26b. Even if an insulating film is generated by oxidizing the surface of the conductive bearing 6 (for example, the inner ring inner peripheral surface 8s or the outer ring outer peripheral surface 10s) in a high temperature environment by providing the energization grounding mechanism that performs It is possible to secure a ground contact (ground contact from the conductive ground members 24a and 24b via the conductive wires 26a and 26b) for a long period of time without receiving the ground.

  In this case, static electricity charged on the shaft 4 and electricity generated due to various factors are energized from the lead wire 26a to the inner ring 8 via the conductive grounding member 24a, and after passing through the conductive lubricant, are electrically conductive from the outer ring 10. The housing 20 can be smoothly and reliably released (grounded) through the ground member 24b and the conductor 26b. As a result, it is possible to realize the conductive bearing 6 having a low electrical resistance that exhibits an excellent energization / grounding function in a high temperature environment for a long period of time. For example, printing is blurred or disturbed by static electricity during toner fixing. It is possible to provide a copying machine and a printer excellent in reproducibility.

Next, a conductive bearing according to a second embodiment of the present invention will be described with reference to FIG.
In the conductive bearing 6 of the present embodiment, the energization / grounding mechanism may be provided in at least one of the inner ring 8 and the outer ring 10, but here, as an example, the case is provided in both the inner ring 8 and the outer ring 10, respectively. Is assumed. In this case, the energization grounding mechanism includes conductive ground members 24a and 24b partially embedded in the race rings (the inner ring 8 and the outer ring 10), and the conductive ground members 24a and 24b are partially formed. It is directly grounded to the external configuration (shaft 4, housing 20).
The materials of the conductive ground members 24a and 24b and the conductive bearing 6 are the same as those in the first embodiment described above, and thus the description thereof is omitted.

Here, an example of a method in which a part of the conductive ground members 24a and 24b is directly grounded to the external configuration (the shaft 4 and the housing 20) will be described.
The conductive ground members 24 a and 24 b can be partially embedded in the inner ring 8 and the outer ring 10 by being pushed into grooves 8 g and 10 g formed in the inner ring 8 and the outer ring 10, respectively. In this case, the grooves 8g and 10g can be set to an arbitrary shape such as a cylindrical shape or a rectangular shape, and the conductive ground members 24a and 24b can be configured in a shape corresponding to the set groove shape. For example, in the case of cylindrical grooves 8g and 10g, spherical conductive earth members 24a and 24b having an outer diameter slightly larger than the inner diameter of the cylindrical grooves 8g and 10g are prepared, and such conductive earth members 24a, By pushing the 24b into the grooves 8g and 10g, part of the conductive ground members 24a and 24b can be firmly embedded in the grooves 8g and 10g.

  Further, it is preferable to set the number of conductive ground members 24a and 24b to be embedded at a predetermined interval (for example, four locations at equal intervals) along the circumferential direction of the inner ring 8 and the outer ring 10. In this case, a number of grooves 8g and 10g corresponding to the set number of embedded holes are formed intermittently at predetermined intervals along the circumferential direction of the inner ring 8 and the outer ring 10, and a conductive ground is provided in each of the grooves 8g and 10g. The members 24a and 24b are embedded. In this state, since the conductive ground members 24a and 24b partially protrude from the grooves 8g and 10g, the inner ring inner peripheral surface 8s is fixed to the shaft 4 and the outer ring outer peripheral surface 10s is fixed to the housing 20. Thus, a part of the conductive ground members 24a and 24b protruding from the grooves 8g and 10g can be grounded to the external configuration (the shaft 4 and the housing 20).

  Further, as described above, instead of embedding the conductive ground members 24a and 24b at predetermined intervals, for example, they may be embedded continuously along the circumferential direction of the inner ring 8 and the outer ring 10. In this case, the grooves 8g and 10g are continuously formed along the circumferential direction of the inner ring 8 and the outer ring 10, and the long conductive ground members 24a and 24b are continuously pushed into the grooves 8g and 10g. . At this time, a part of the long conductive ground members 24a and 24b continuously protrudes along the grooves 8g and 10g, the inner ring inner peripheral surface 8s is fixed to the shaft 4, and the outer ring outer peripheral surface 10s is housed in the housing. By fixing to 20, a part of the conductive ground members 24a, 24b protruding continuously can be grounded with a wide grounding area with respect to the external configuration (the shaft 4, the housing 20).

  As described above, according to the second embodiment, part of the conductive ground members 24a and 24b partially embedded in the race rings (the inner ring 8 and the outer ring 10) is directly connected to the external configuration (the shaft 4 and the housing 20). Even if an insulating film is generated by oxidizing the surface of the conductive bearing 6 (for example, the inner ring inner peripheral surface 8 s or the outer ring outer peripheral surface 10 s) in a high temperature environment by providing an energization ground mechanism for grounding, An unaffected ground contact (a ground contact in which a part of the conductive ground members 24a and 24b is directly grounded to the external configuration) can be secured for a long period of time.

  In this case, static electricity charged on the shaft 4 and electricity generated due to various factors are energized from the conductive ground member 24a to the inner ring 8 and after passing through the conductive lubricant, the outer ring 10 passes through the conductive ground member 24b. Thus, the housing 20 can be smoothly and reliably released (grounded). As a result, it is possible to realize the conductive bearing 6 having a low electrical resistance that exhibits an excellent energization / grounding function in a high temperature environment for a long period of time. For example, printing is blurred or disturbed by static electricity during toner fixing. It is possible to provide a copying machine and a printer excellent in reproducibility.

Next, a conductive bearing according to a third embodiment of the present invention will be described with reference to FIG.
In the conductive bearing 6 of the present embodiment, the conductive earth members 24a and 24b of the energizing and grounding mechanism have their base ends embedded in the race rings (inner ring 8 and outer ring 10), and their distal ends are externally configured (shafts). 4, fitted in the housing 20) and grounded. The energization / grounding mechanism of the present embodiment may be provided on at least one of the inner ring 8 and the outer ring 10, but here, as an example, it is assumed that both are provided on both the inner ring 8 and the outer ring 10. Further, the materials of the conductive ground members 24a and 24b and the conductive bearing 6 are the same as those in the first embodiment described above, and thus the description thereof is omitted.

Here, an example of a method in which the tips of the conductive ground members 24a and 24b are fitted to the external configuration (the shaft 4 and the housing 20) and grounded will be described.
In this method example, rod-shaped conductive ground members 24a and 24b are prepared, and the base ends thereof are embedded in grooves 8g and 10g formed in the inner ring 8 and the outer ring 10, respectively, and the distal ends thereof are externally configured (shaft 4). And is fitted into the housing 20). In this case, it is preferable to design the tips of the conductive ground members 24a and 24b to have a tapered shape. As a result, the tip portion can be securely (tightly) fitted to the external configuration (the shaft 4 and the housing 20).

  Further, for example, a male screw may be formed at the tip portion, a female screw may be formed in the external configuration, and the male screw may be screwed into the female screw. According to this, the front ends of the conductive ground members 24a and 24b can be more firmly fitted into the external structure (the shaft 4 and the housing 20).

Further, the number of conductive ground members 24a and 24b to be fitted into the external configuration and the fitting positions may be set such that a plurality of conductive ground members 24a and 24b are fitted at predetermined intervals, as in the second embodiment. Alternatively, the grooves 8g and 10g are continuously formed along the circumferential direction of the inner ring 8 and the outer ring 10, and the long conductive ground members 24a and 24b are continuously embedded in the grooves 8g and 10g. You may make it a front-end | tip part fit continuously in an external structure (the shaft 4, the housing 20).
Note that the effect of the third embodiment is the same as that of the second embodiment described above, and a description thereof will be omitted.

Next, a conductive bearing according to a fourth embodiment of the present invention will be described with reference to FIG.
In the conductive bearing 6 of the present embodiment, the conductive ground members 24a and 24b of the energization ground mechanism are urged toward the external configuration (the shaft 4 and the housing 20) by the urging means 30, and the external configuration It is maintained in a state where it is directly grounded. The energization / grounding mechanism of the present embodiment may be provided on at least one of the inner ring 8 and the outer ring 10, but here, as an example, it is assumed that both are provided on both the inner ring 8 and the outer ring 10. Further, the materials of the conductive ground members 24a and 24b and the conductive bearing 6 are the same as those in the first embodiment described above, and thus the description thereof is omitted.

Here, an example of a method in which the conductive ground members 24a and 24b are urged toward the external configuration (the shaft 4 and the housing 20) and grounded will be described.
In this method example, cylindrical grooves 8g and 10g are formed in the inner ring 8 and the outer ring 10, and the urging means 30 is disposed in the grooves 8g and 10g. As the urging means 30, a conductive spring such as a compression spring or a spring may be applied. Then, conductive ground members 24 a and 24 b are set at the tip of the biasing means 30. In this case, the conductive ground members 24a and 24b are set so as to protrude from the grooves 8g and 10g in a state where the conductive ground members 24a and 24b are set at the tip of the urging means 30.

  Thereafter, the inner ring inner peripheral surface 8s is fixed to the shaft 4 and the outer ring outer peripheral surface 10s is fixed to the housing 20, whereby a part of the conductive ground members 24a and 24b protruding from the grooves 8g and 10g is externally configured (shaft 4. The housing 20) can be grounded. In this case, the static electricity charged in the shaft 4 is energized from the conductive ground member 24a to the inner ring 8 via the biasing means 30, and after passing through the conductive lubricant, the biasing means 30 and the conductive grounding from the outer ring 10 are conducted. The housing 20 can be smoothly and reliably released (grounded) via the member 24b.

  As described above, according to the fourth embodiment, the conductive ground members 24a and 24b are elastically grounded to the external structure (the shaft 4 and the housing 20) by the biasing means 30. In this case, for example, even if the dimensions of the inner and outer rings 8 and 10 and the external configuration change due to thermal expansion, the biasing means 30 can elastically absorb the change, so that the conductive earth member 24a for the external configuration can be obtained. Therefore, the grounding state (grounding pressure) of 24b can always be kept constant. As a result, it is possible to realize the conductive bearing 6 having a low electrical resistance that exhibits an excellent energization / grounding function over a long period of time in a high temperature environment.

  The shape of the conductive earth members 24a and 24b can be designed in various shapes such as a spherical shape or a rectangular shape, for example. Therefore, the energization / grounding efficiency can be further improved. Since other effects are the same as those of the second embodiment described above, description thereof is omitted.

Here, the comparison result measured about the electroconductivity of the electroconductive bearing 6 (FIG. 1) of this Embodiment and the existing electroconductive bearing 6 (FIG. 3) is considered with reference to FIG.
In this measurement, both bearings are configured with an inner diameter of 30 mm, an outer diameter of 42 mm, a width of 7 mm, and a preload of 20 kgf, and a bearing at a rotational speed of 150 rpm in a high temperature environment of 200 ° C. The change in the maximum resistance value with respect to the durability time when rotating was measured.
In Comparative Examples 1 to 5, five existing conductive bearings 6 (FIG. 3) are prepared and the change in the maximum resistance value of each bearing is shown. Examples 1 to 5 are the above-described first examples. ~ 5 conductive bearings 6 (FIG. 1) of the fourth embodiment are arbitrarily selected, and the change in the maximum resistance value of each bearing is shown.

  As is apparent from the comparison results, the existing conductive bearing 6 (FIG. 3) has a variation in the maximum resistance value as the durability time becomes longer. On the other hand, the conductive bearing 6 (FIG. 3) of the present embodiment ( In Fig. 1), the maximum resistance value is maintained at a substantially constant value regardless of the endurance time. As a result, the conductive bearing 6 (FIG. 1) of the present embodiment smoothly and reliably releases electricity generated by static electricity and various factors without being affected by the generation of the insulating film in a high temperature environment (grounding). You can see that

(a) is sectional drawing which shows the structural example of the electroconductive bearing which concerns on the 1st Embodiment of this invention, (b) is the structural example of the electroconductive bearing which concerns on the 2nd Embodiment of this invention. Sectional drawing shown, (c) is a sectional view showing a configuration example of a conductive bearing according to a third embodiment of the present invention, (d) is a conductive bearing according to a fourth embodiment of the present invention Sectional drawing which shows the example of a structure. The figure which shows the comparison result measured about the electroconductivity of the electroconductive bearing of this Embodiment, and the existing electroconductive bearing. Sectional drawing which shows the structural example of the conventional electroconductive bearing.

Explanation of symbols

4 Shaft 6 Conductive bearing 8 Inner ring 10 Outer ring 12 Rolling element 22 Sealing plate
24a, 24b Conductive grounding member (electrical grounding mechanism)

Claims (5)

It is provided with a bearing ring arranged so as to be capable of relative rotation, a plurality of rolling elements arranged so as to be able to roll between the bearing rings, and sealing plates provided between the bearing rings on both sides of these rolling elements. A conductive bearing filled with conductive grease,
Each of the bearing rings is fixed to a predetermined external configuration, and at least one of the race rings is provided with an energization grounding mechanism for grounding the external configuration.   The conductive grounding mechanism includes a conductive grounding member embedded in the raceway ring, and the conductive grounding member is grounded to an external configuration through a conductive wire. Bearing.   The conductive grounding mechanism includes a conductive grounding member partially embedded in the race, and a part of the conductive grounding member is directly grounded to an external configuration. The conductive bearing described in 1.   The energization grounding mechanism is provided with a conductive grounding member whose base end is embedded in the raceway ring, and the conductive grounding member is grounded by fitting its distal end into an external configuration. The conductive bearing according to claim 1. The energization grounding mechanism includes a conductive grounding member that can be directly grounded to an external configuration, and a biasing unit that biases the conductive grounding member toward the external configuration and directly grounds the conductive grounding member. The conductive bearing according to claim 1.

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