JP6074329B2 - Bearing with magnetic fluid seal - Google Patents

Description

  The present invention relates to a bearing with a magnetic fluid seal that is disposed in various power transmission mechanisms and rotatably supports a rotating shaft, and prevents foreign matter such as dust and moisture from entering inside.

  Generally, a rotating shaft installed in various driving force transmission mechanisms is rotatably supported via a bearing. In this case, a so-called ball bearing (ball bearing) in which a plurality of rolling elements (rolling members) are accommodated in the circumferential direction between the inner ring and the outer ring is often used as the bearing. By using it, the rotational performance of the rotating shaft is improved.

  Such a bearing is used as a support means for a rotating shaft of a driving force transmission mechanism in various driving devices. However, depending on the driving device, foreign matter such as dust and moisture can be prevented from entering inside the bearing portion. There is something I want to do. In addition, when foreign matter enters the bearing itself, problems such as deterioration in rotational performance and abnormal noise occur. As a countermeasure against such a problem, a seal member made of an elastic material is brought into contact with the outer periphery of the rotating shaft close to the bearing to make the bearing portion waterproof and dust-proof. However, the seal member made of an elastic material is used. The rotational performance of the rotating shaft is degraded due to the influence of the contact pressure.

  Accordingly, a bearing (referred to as a bearing with a magnetic fluid seal) having a magnetic fluid seal mechanism using a magnetic fluid is known as a configuration for preventing foreign matter from entering the bearing portion without deteriorating the rotational performance of the rotary shaft. ing. For example, Patent Document 1 relates to a ball bearing that holds a rolling element between an outer ring and an inner ring, interposing a magnetic body between the outer ring and the inner ring that rotate relative to each other, and fixing one side of the magnetic body, A configuration in which a magnetic fluid is disposed in the seal gap on the other side is disclosed.

  Specifically, a magnetic fluid seal that forms a magnetic circuit between the inner ring or the outer ring and seals the inside of the bearing body is integrally held on the bearing body composed of an inner ring, an outer ring, and a rolling element. Consists of a magnet that forms a magnetic circuit with the inner ring or the outer ring, a holding plate that holds the magnet, and a magnetic fluid that is held between the inner ring or the outer ring and the holding plate.

  That is, the rolling element is closed by disposing the magnetic body between the inner ring and the outer ring to close the rolling element, fixing one side of the magnetic body, and disposing the magnetic fluid in the seal gap on the other side. Sealed in a sealed state to prevent foreign matter from entering the rolling elements that affect the rotational performance.

JP2013-110A

  By the way, according to the bearing with a magnetic fluid seal disclosed in the above-mentioned Patent Document 1, since the rolling element is generally formed of a magnetic material such as SUS440C, the rolling element is a magnet of the magnet constituting the magnetic fluid seal. There is a problem that the movement of the rolling element becomes bad. That is, since the rolling elements are attracted to the inner and outer rings by the magnetic force, there is a problem that the rolling elements are difficult to roll smoothly (rotational torque increases).

  As described above, in the bearing with a magnetic fluid seal described above, while the sealing performance can be greatly improved as compared with the conventional bearing, the rolling element is affected by the magnet and the rotational torque is increased, that is, it is difficult to rotate. The problem of becoming is inherent.

  The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide a bearing with a magnetic fluid seal capable of realizing a smooth rolling of a rolling element by reducing rotational torque.

In order to achieve the above-mentioned object, a bearing with a magnetic fluid seal according to the present invention is a roller that is inserted between a ring that is made of a magnetic material, an outer ring that is made of a magnetic material, and the inner and outer rings. A bearing body having a moving body; and a magnetic fluid seal that is integrally held by the bearing body and forms a magnetic circuit with the inner ring or the outer ring to seal the inside of the bearing body. The seal is magnetized so that a magnetic pole faces in the axial direction of the bearing body, and a ring-shaped magnet disposed on the opening side of the inner ring and the outer ring, and the magnet is opposed to the rolling element. A ring having substantially the same shape as the magnet, which is attached to the outer side surface in the axial direction of the magnet and forms a gap on the other side with either the inner surface on the inner ring side or the outer surface on the outer ring side as a fixed side. And at least the electrode plate Also has a magnetic fluid held in the gap, the rolling element of the bearing body, characterized in that it consists of non-magnetic material.

  According to the above-described configuration, since the rolling element is formed of a non-magnetic material, the rolling element is not affected by the magnetic force from the magnet of the magnetic fluid seal. Therefore, the rotational torque can be reduced and the rolling element can be smoothed. Can achieve smooth rolling. The advantage of making the rolling element non-magnetic is that the influence of the magnet directly affects the rolling element, such as an arrangement in which the magnet directly faces the rolling element without interposing a pole plate (such as this In such a situation, when the rolling element is a magnetic body, the rolling element directly receives the magnetic force of the magnet, and the rotation of the rolling element becomes considerably heavy. In addition, when the rolling element is made of a non-magnetic material, the rolling element can be formed from a lightweight material such as ceramic, and thus the weight of the entire bearing can be reduced.

  According to the present invention, it is possible to obtain a bearing with a magnetic fluid seal capable of reducing rotational torque and realizing a smooth rolling of a rolling element.

It is a figure which shows 1st Embodiment of the bearing with a magnetic fluid seal which concerns on this invention, and sectional drawing along an axial direction. The principal part enlarged view of FIG. The figure which shows the modification of 1st Embodiment. It is a figure which shows 2nd Embodiment of the bearing with a magnetic fluid seal which concerns on this invention, and sectional drawing along an axial direction. The principal part enlarged view of FIG. The side view which has a partial cross section of the spinning reel which can apply the bearing with a magnetic fluid seal concerning this invention. Sectional drawing of the double bearing type | mold reel which can apply the bearing with a magnetic fluid seal concerning this invention.

Hereinafter, embodiments of a bearing with a magnetic fluid seal according to the present invention will be described with reference to the drawings.
1 and 2 are views showing a first embodiment of a magnetic fluid seal bearing according to the present invention. FIG. 1 is a sectional view along an axial direction, and FIG. 2 is an enlarged view of a main part of FIG. is there.

  A magnetic fluid seal bearing (hereinafter also referred to as a bearing) 1 according to this embodiment includes a cylindrical inner ring 3, a cylindrical outer ring 5 surrounding the inner ring 3, and an inner ring 3 and an outer ring 5. A bearing body including a plurality of rolling elements (rolling members) 7 is provided. The rolling element 7 is held by a retainer (cage) 8 extending in the circumferential direction, and the inner ring 3 and the outer ring 5 are relatively rotatable.

  The inner ring 3 and the outer ring 5 are made of a magnetic material, for example, chromium-based stainless steel (SUS440C), and the retainer 8 is made of a material excellent in corrosion resistance and heat resistance, for example, stainless steel (SUS304). Further, the rolling element 7 is a non-magnetic material such as ceramic (silicon nitride, alumina, zirconia, SiC, etc.), non-magnetic steel (austenite stainless steel, titanium, titanium alloy, super hard material (tungsten carbide, etc.), It is made of copper alloy, plastic or the like. In addition, the outer ring 5 of the present embodiment is configured such that the exposed end surface 5a is on the same surface (substantially the same surface) as the exposed end surface 3a of the inner ring 3, but either one is formed longer than the other. It may be.

  A magnetic fluid seal 10, which will be described in detail below, is installed on the opening side of the inner ring 3 and the outer ring 5. As will be described later, the magnetic fluid seal 10 is integrally held by the bearing body (may be integrated with the bearing body and configured as a unit together with the bearing body), and the magnetic circuit between the inner ring 3 and the outer ring 5. Specifically, a magnet that forms a magnetic circuit with the inner ring 3 or the outer ring 5, a pole plate that holds the magnet, and the inner ring 3 or the outer ring is sealed. 5 and a magnetic fluid held between the pole plate and / or the magnet. In the present embodiment, the magnetic fluid seals 10 having the same configuration are disposed in the openings on both sides of the inner ring 3 and the outer ring 5, and therefore, in the following description, the configuration on one side (left side in FIG. 1) will be described. .

  The magnetic fluid seal 10 includes a ring-shaped magnet (hereinafter referred to as a magnet) 12 and a ring-shaped electrode plate (hereinafter referred to as an electrode plate) 14 disposed in contact with the axially outer surface of the magnet 12. And a magnetic fluid (outer ring side magnetic fluid 15a, inner ring side magnetic fluid 15b) held in a magnetic circuit formed by the magnet 12, and by these members, in the rolling element 7, It has a function of sealing so that dust, moisture and the like do not enter.

  In this embodiment, the magnetic fluid is provided at two locations on the outer ring side and the inner ring side, but may be provided only at any one location. In the present embodiment, the electrode plate 14 is provided only on one side (the axially outer side) of the magnet 12, but the electrode plate 14 is provided on both sides of the magnet 12 (the electrode plate 14 holds the magnet 12 from both sides). You may)

  The magnet 12 is attached to the pole plate 14 so as to face the rolling element 7 (the pole plate 14 holds one side of the magnet 12 and the other side of the magnet 12 faces the rolling element 7). The electrode plate 14 has one of the inner surface on the inner ring side and the outer surface on the outer ring side as a fixed side. Note that the magnet 12 of this embodiment is in a state of being bonded to the electrode plate 14 in advance, and the inner peripheral surface 12 a is formed in a size that does not protrude from the inner peripheral surface 14 a of the electrode plate 14.

  As the magnet 12, a permanent magnet having a high magnetic flux density and a strong magnetic force, for example, a neodymium magnet produced by a sintering method can be used. As shown in FIG. X) is magnetized so that the magnetic poles (S pole, N pole) face it. In addition, the electrode plate 14 is disposed in contact with the outer surface of the magnet 12 in the axial direction. The electrode plate 14 has substantially the same shape as the magnet 12, and is made of a magnetic material, for example, chromium-based stainless steel (SUS440C).

  The magnet 12 and the electrode plate 14 are attached at the time of assembly, and in the present embodiment, both members are bonded in advance, but may not be bonded. In this case, by pre-bonding the two, the magnet 12 can be easily positioned and centered, and the magnet 12 and the electrode plate 14 are unitized so that an assembling operation as described later can be easily performed. .

  The electrode plate 14 of the present embodiment has an outer diameter that is slightly larger than the inner peripheral surface of the outer ring 5, and is press-fitted together with the bonded magnet 12 from the opening side of the outer ring 5. Yes. The electrode plate 14 to which the magnet 12 is bonded is formed in such a size that a gap G is formed between the outer plate 5 and the outer ring 5 when the electrode plate 14 is pressed into the outer ring 5.

  The magnet 12 is not sandwiched between a pair of pole plates as in the conventional magnetic seal mechanism, but the pole plate 14 is disposed only on one magnetic pole side (S pole side in this embodiment). When the magnetic fluid is injected into the gap G between the inner ring 3 and the electrode plate 14, the magnetic fluid not only accumulates in the gap G with the inner ring 3 (forms the inner ring-side magnetic fluid 15b), but also the surface of the magnet 12 Thus, it is possible to accumulate on the press-fitting side (form the outer ring-side magnetic fluid 15a).

  Specifically, as shown in FIG. 2, the magnetic circuit 3M holds the gap G between the pole plate 14 and the inner ring 3 and the gap between the magnet 12 and the inner ring 3, and the magnetic circuit 5M 12 and the minute gap generated between the outer ring 5 and the minute gap generated between the electrode plate 14 and the outer ring 5. That is, as described above, the electrode plate 14 to which the magnet 12 is bonded is press-fitted into the outer ring 5, but due to the influence of the dimensional accuracy of the electrode plate 14 and the magnet 12, production errors, etc. Even if there is a slight gap, the injected magnetic fluid can flow into that portion, and a reliable seal is formed even on the fixed side.

The magnetic fluid to be injected (outer ring side magnetic fluid 15a, inner ring side magnetic fluid 15b) is composed of, for example, magnetic fine particles such as Fe ₃ O ₄ dispersed in base oil with a surfactant (surfactant). Is dispersed in the base oil by covering the particles with magnetic fine particles), and has a characteristic of reacting when the magnet is brought close to the magnet. For this reason, the magnetic fluids 15a and 15b are stably placed in predetermined positions by the magnetic circuits 3M and 5M formed between the magnet 12 and the inner ring 3, outer ring 5 and pole plate 14 made of a magnetic material. Retained. In this case, since there is no electrode plate on the rolling element 7 side of the magnet 12, the magnetic fluid easily moves to the press-fitting side to form the outer ring-side magnetic fluid 15a.

  Further, a step 5b is formed on the inner surface of the outer ring 5 on the side of the rolling element 7 with respect to the magnet 12, and the step 5c causes the outer ring 5 to have a thin area 5A on the opening side and a thick area 5B on the rolling element side. Thus, the inner and outer ring intervals on the outer side in the axial direction are formed larger than those on the inner side. The step 5b is formed so as to generate a gap (step gap) for holding the magnetic fluid. In the present embodiment, the step 5b is formed to be a surface 5c perpendicular to the axial direction ( By using a vertical surface, the magnet 12 can be attracted, positioned and fixed. Note that the step is not limited to a vertical surface as in this embodiment, and can be formed in a step shape as long as the magnetic fluid can be stably held between the magnet 12 and It may be formed in an inclined shape (slope). In this case, it is possible to position the magnet 12 and hold the magnetic fluid by using the inclined surface.

  As described above, the outer diameter of the electrode plate 14 is slightly larger than the inner peripheral surface of the outer ring 5 (the inner peripheral surface of the thin wall region 5A). It is press-fitted into the opening side. Further, the electrode plate 14 to which the magnet 12 is bonded is formed in such a size that a predetermined gap G is generated between the electrode plate 14 and the outer ring surface of the inner ring 3 when press-fitted into the outer ring 5. Further, the axial lengths of the magnet 12 and the electrode plate 14 are formed such that a gap G1 is generated with respect to the vertical surface 5c by the step 5b when the magnet 12 and the electrode plate 14 are press-fitted in a state where they are adhered. Yes.

  As described above, when the pole plate 14 to which the magnet 12 magnetized so that the magnetic pole is directed in the axial direction is press-fitted into the outer ring 5, the inner ring 3 side and the outer ring 5 side are Magnetic fluxes (magnetic circuits 3M and 5M) that are symmetric with respect to the direction are formed. Therefore, the inner ring-side magnetic fluid 15b and the outer ring-side magnetic fluid 15a are held in the gap G between the electrode plate 14 and the inner ring 3 and the gap G1 between the magnet 12 and the outer ring 5, respectively. It becomes possible to make it. Specifically, as described above, when the magnetic fluid is filled in the gap G with an injection device such as a dropper, the magnetic fluid is held in the gap G by the magnetic circuit 3M, and moves to the gap G1 side as it is and is formed on the outer ring side. The magnetic circuit 5M is held in the gap G1.

  As described above, according to the present embodiment, since the rolling element 7 is formed of a nonmagnetic material, the rolling element 7 is not affected by the magnetic force from the magnet 12 of the magnetic fluid seal 10, and therefore, the rotational torque. Therefore, smooth rolling of the rolling element 7 can be realized. The advantage that the rolling element 7 is made of a non-magnetic material is that the magnet 12 is directly opposed to the rolling element 7 without using the electrode plate 14 as in the present embodiment (the electrode plate 14 is the magnet 12). Of the magnet 12 and the other side of the magnet 12 is opposed to the rolling element 7). If the rolling element is a magnetic substance in such an arrangement, the rolling element directly receives the magnetic force of the magnet, and the rotational torque of the rolling element increases, making it difficult to roll.

  Further, when the rolling element 7 is made of a non-magnetic material as in the present embodiment, the rolling element 7 can be formed from a light material such as ceramic, and thus the weight of the entire bearing can be reduced.

  It is apparent from the experimental data shown in Table 1 and Table 2 that the rotational torque can be reduced by making the rolling element 7 nonmagnetic. Table 1 shows an ordinary ball bearing without a magnetic fluid seal (conventional product) and a ball bearing with a magnetic fluid seal (product of Patent Document 1) in a bearing (ball bearing) having an inner diameter of 9 mm and an outer diameter of 17 mm. It is the experimental result which compared with the bearing with a magnetic fluid seal (ball bearing) (this application product) of the structure of this embodiment which formed the rolling element (ball) from the ceramic material regarding rotational torque. In this experiment, the rotational torque of the outer ring generated when the inner ring was rotated at a predetermined constant speed was measured. In these three types of bearing forms, SUS440C was used as the material (material) of the inner ring and the outer ring. Further, in the bearing form of the present embodiment, ceramic (silicon nitride) is used as the material (material) of the rolling element. However, in the other two types of bearing forms, SUS440C is used as the material (material) of the rolling element. It was done. In addition, grease was lubricated to the bearings.

  As can be seen from Table 1, in the bearing configuration of the present embodiment (product of the present application), a low rotational torque substantially equal to that of a normal ball bearing (conventional product) without a magnetic fluid seal was shown. On the other hand, the rotational torque of the ball bearing with magnetic fluid seal (Patent Document 1 product) reached about three times the rotational torque of the bearing configuration of the present embodiment (product of the present application). Further, when a similar experiment was conducted with a bearing (ball bearing) having an inner diameter of 7 mm and an outer diameter of 13 mm, as shown in Table 2, the rotational torque of the bearing configuration of the present embodiment (product of the present application) is magnetic. It became the same as that of a normal ball bearing (conventional product) without a fluid seal.

  Further, according to the bearing 1 having the above-described configuration, a sealing effect is obtained even on the side on which the magnet 12 and the electrode plate 14 are fixed (in this embodiment, the inner peripheral surface of the outer ring 5). It is possible to reliably prevent low moisture and dust from entering the rolling element 7 side. That is, the conventional bearing with a magnetic fluid seal does not consider the necessity of sealing on the side on which the magnet and the electrode plate are fixed, and the sealing effect on the rolling elements is not sufficient. In addition to the sealing of the inner ring side magnetic fluid 15b, the outer ring side magnetic fluid 15a on the fixed side is also sealed, so that a sufficient sealing effect can be exhibited.

  Further, when sealing, it is only necessary to magnetize the magnetic pole of the magnet 12 which is one member so as to be in the axial direction, and to arrange it so as to be in contact with the pole plate 14, so that the number of parts is small, and Since the magnet 12 does not need to have a precise dimensional accuracy, the assembling work is facilitated and the cost can be reduced. That is, a sufficient sealing effect can be exhibited even when a magnet having a disadvantage in dimensional accuracy is used with respect to other members.

  Furthermore, the magnet 12 that holds the magnetic fluid on both the inner ring side and the outer ring side is configured as one member, and a magnetic fluid seal is formed on the inner ring side and the outer ring side at the same time by lubrication work from one place. Therefore, workability is improved.

  Further, in the present embodiment, since the step 5b is formed in the outer ring 5, a space (step gap) for effectively holding the magnetic fluid can be formed using the step, and the sealing effect can be easily achieved. Can be increased. In FIG. 2, the outer ring-side magnetic fluid 15 a is held in the gap G <b> 1, but the gap between the outer peripheral surface of the magnet 12 and the inner peripheral surface of the outer ring 5, or the inner periphery of the electrode plate 14 and the outer ring 5. It is possible to penetrate even a slight gap between the surfaces, and a sufficient sealing function is exhibited on the outer ring side.

FIG. 3 is a diagram illustrating a modification of the above-described embodiment.
In the embodiment shown in FIGS. 1 and 2, the electrode plate 14 is configured with the same thickness in the radial direction. However, as shown in FIG. 3, a portion for holding a magnetic fluid (in this embodiment, It is preferable to form a taper so that the thickness gradually decreases toward the inner side in the radial direction (the thin-walled portion is indicated by reference numeral 14A).

  According to such a configuration, since the magnetic fluid 15b does not jump out to the outside in the axial direction (outside from the exposed end surfaces 5a and 3a of the outer ring and the inner ring), the magnetic fluid is prevented from being wiped off during the assembling work. It is possible to perform a stable filling operation.

  4 and 5 are views showing a second embodiment of the magnetic fluid seal bearing according to the present invention, FIG. 4 is a sectional view along the axial direction, and FIG. 5 is an enlarged view of a main part of FIG. is there.

  Also in this embodiment, the rolling elements 7 constituting the bearing body are formed of a non-magnetic material as in the first embodiment. In addition to this, in this embodiment, the magnet 12 is arranged as shown in the figure. The attached electrode plate 14 is positioned in a state of being recessed from the end surface 5a of the outer ring 5 and the end surface 3a of the inner ring 3. Specifically, as shown in FIG. 5, the electrode plate 14 is positioned such that the end surface (exposed end surface) 14 b on the opening side is recessed by a predetermined amount H with respect to the end surface 5 a of the outer ring and the end surface 3 a of the inner ring. (As a result, the axial gap G1 between the magnet 12 and the outer ring 5 is smaller or eliminated as compared with the first embodiment).

  In this case, the amount of depression H is such that the magnetic fluid 15a, 15b held in the seal portion can be prevented from adhering to the finger even if the outer ring portion or the inner ring portion is picked by a finger due to maintenance or the like. It may be 0.01 to 1.0 mm, preferably about 0.05 mm to 0.5 mm. That is, when it is shallower than 0.01 mm, it tends to adhere to the finger or come into contact with other objects when it is picked with a finger, and when it is deeper than 1.0 mm, the axial length is unnecessary. This is not preferable because it becomes longer and affects the incorporation property. In addition, you may form the tapers 30 and 50 in the end surface of an inner and outer ring | wheel over the circumferential direction, respectively. By forming such a taper, it becomes easy to incorporate the bearing.

  In the present embodiment, a step 3 </ b> B is formed on the end face of the inner ring 3. The step 3B is formed in a stepped shape including a surface 3b perpendicular to the axial direction X, and the electrode plate 14 is within the axial thickness range (between points A and B). The inner edge 3b 'formed by the step 3B is press-fitted so as to be positioned. That is, by forming such a stepped step 3B, the magnetic fluid 15b is held between the vertical surface 3b at the depressed position without rising from the end surface 14b of the electrode plate 14. Become. In this case, if the position C of the inner edge 3b ′ becomes lower than the point B, the magnetic fluid is not sufficiently held between the electrode plate 14 and the inner ring. Also, if the position C of the inner edge 3b 'is higher than the point A, the magnetic fluid will rise, and when the outer ring part or the inner ring part is picked with a finger, it will be easily attached to the finger. .

  In the configuration of the step 3B described above, the radial thickness D of the vertical surface 3b is preferably set larger than the gap G (the gap from the end surface 14a of the electrode plate 14 to the inner edge 3b ′). That is, the thickness of the radial thickness D is not particularly limited, but by keeping a certain distance (set larger than the gap G), the swell of the magnetic fluid 15b is suppressed. Thus, when a finger touches the end region of the inner ring, it is possible to effectively prevent the magnetic fluid from adhering to the finger.

  Also in this embodiment, as described above, when the pole plate 14 to which the magnet 12 magnetized so that the magnetic poles are directed in the axial direction is press-fitted into the outer ring 5, the inner ring 3 side and the outer ring 5 side are As shown, magnetic flux (magnetic circuits 3M, 5M) that is symmetric with respect to the axial direction is formed. For this reason, when the magnetic fluid is injected into the gap G portion by means of an injection device such as a dropper, the inner ring side magnetic fluid 15b is formed by being held in the gap G by the magnetic circuit 3M. The magnetic circuit 5M accumulates in a gap between the magnet portion (between the magnet 12 and the surface 5c perpendicular to the magnet 12) and the electrode plate portion on the outer ring 5 side to form the outer ring-side magnetic fluid 15a.

  For this reason, since the sealing effect is obtained also on the side where the magnet 12 and the electrode plate 14 are fixed (in this embodiment, on the inner peripheral surface side of the outer ring 5), the rolling elements of moisture and dust having low viscosity from the fixed side are obtained. Intrusion to the 7 side can be reliably prevented. That is, the conventional bearing with a magnetic fluid seal does not consider the necessity of sealing on the side on which the magnet and the electrode plate are fixed, and the sealing effect on the rolling elements is not sufficient. In addition to the sealing of the inner ring side magnetic fluid 15b, the outer ring side magnetic fluid 15a on the fixed side is also sealed, so that a sufficient sealing effect can be exhibited. In this case, the inner ring side magnetic fluid 15 b may be held between the inner ring 3 and the pole plate 14 and / or between the inner ring 3 and the magnet 12. Further, the outer ring-side magnetic fluid 15 a only needs to be held between the outer ring 5 and the electrode plate 14 and / or between the outer ring 5 and the magnet 12.

  In addition, the magnet 12 that holds the magnetic fluid on both the inner ring side and the outer ring side is configured as one member, and a magnetic fluid seal is formed on the inner ring side and the outer ring side at the same time by lubrication work from one place. Therefore, workability is improved. In particular, in the present embodiment, the electrode plate 14 is positioned so that the end surface (exposed end surface) 14a on the opening side is recessed by a predetermined amount H with respect to the end surface 5a of the outer ring and the end surface 3a of the inner ring. Fingers and work tools are prevented from touching magnetic fluid during injection work and maintenance work, etc., which improves handling and prevents outflow of magnetic fluid and weakens sealing performance. Absent.

  In the configuration of the above-described embodiment and the modified example, it is preferable that the surfaces of the inner ring 3 and the outer ring 5 are subjected to electrolytic chromic acid treatment. By applying electrolytic chromic acid treatment in this way, it is possible to prevent the surface from cracking and tearing due to rust and corrosion, and it is possible to reliably prevent dust and foreign matter from entering the inside. Become.

  In the above configuration, a ring-shaped shield (sealing cover) may be press-fitted and fixed from the outside in the axial direction on the surface on the outer side in the axial direction of the electrode plate 14 disposed on the opening side. Such a shield can be formed of a material excellent in corrosion resistance and heat resistance, such as stainless steel (SUS304) or resin, and the provision of such a shield makes it more effective to intrude foreign matter. It is possible to effectively prevent magnetic substances (foreign matter) such as iron sand from adhering to the magnet 12.

  Furthermore, in the above-described configuration, a thin washer and a spacer member for positioning may be disposed between the magnet 12 and the vertical surface 5c of the step 5b of the outer ring 5. By disposing such washers and spacers, dimensional management is simplified, and it is possible to further improve the assemblability. These washers and spacers are preferably made of a magnetic material so that a stable magnetic circuit is formed.

  About the bearing provided with the magnetic fluid seal comprised as mentioned above, it can be installed in the rotating shaft part of various apparatuses in which dust resistance and waterproofness are requested | required, and especially has salt content (seawater) Under the environment, it will be a severe condition. That is, since seawater has a low viscosity, it easily penetrates from a small gap, and when it enters and then dries, the salt content crystallizes and remains, and if such crystals adhere to the rolling element part, the rotational performance This is because the remarkably decreases.

For this reason, about the bearing of embodiment mentioned above, it arrange | positions in the drive-shaft part of the power transmission part in the various fishing reels used on the seaside or the sea, and a drive-shaft part is stabilized over a long period of time. It is possible to support.
For example, it is preferable to dispose the bearings of the above-described embodiments on a rotating shaft portion (for example, a pinion shaft) that is driven to rotate by a handle of the spinning reel and a spool shaft portion of a dual-bearing reel. Moreover, the bearing of embodiment mentioned above is applicable also to a one-way clutch bearing.

  For example, the bearing of the above-described embodiment is a rotating shaft portion that is rotationally driven by a handle rotating operation such as the handle shaft 61 and the pinion shaft 62 of the fishing spinning reel 60 as shown in FIG. Or a support portion of the line roller 65 that guides the fishing line to the spool 64. In the case of the double bearing type reel 70 as shown in FIG. 7, the bearing 72 of the handle shaft 71, the bearing 74 of the pinion shaft 73, and the like can be constituted by the above-described bearings with a magnetic fluid seal. In particular, it can be rotatably disposed between the left and right side plates 75A and 75B of the reel body, and can be disposed on the bearing 80 portion that supports the spool shaft 78 portion in which the winding power transmission state is turned ON / OFF by the clutch mechanism 76. . In particular, since the bearing with a magnetic fluid seal of the above-described embodiment can obtain a smooth rotation performance of the bearing (without the rolling element being affected by the magnet), the spool of the double-bearing type reel that requires a free rotation performance. It can be used for the bearing portion of the shaft, and the application range of the fishing reel bearing is expanded. Further, the magnetic fluid seal of the type of bearing described above can be applied to the one-way bearing 90.

DESCRIPTION OF SYMBOLS 1 Bearing with magnetic fluid seal 3 Inner ring 5 Outer ring 7 Rolling element 10 Magnetic fluid seal 12 Magnet 14 Electrode plate 15a Outer ring side magnetic fluid 15b Inner ring side magnetic fluid

Claims (5)

A bearing body having an inner ring made of a magnetic body, an outer ring made of a magnetic body, and a rolling element that is inserted between the inner ring and the outer ring so as to allow rolling.
A magnetic fluid seal that is integrally held in the bearing body, forms a magnetic circuit with the inner ring or the outer ring, and seals the inside of the bearing body;
With
The magnetic fluid seal is
A ring-shaped magnet that is magnetized so that the magnetic pole faces in the axial direction of the bearing body, and is disposed on the opening side of the inner ring and the outer ring ;
The magnet is attached to the outer side surface in the axial direction of the magnet so as to face the rolling element, and one of the inner surface on the inner ring side and the outer surface on the outer ring side is a fixed side, and a gap is formed on the other side. A ring-shaped electrode plate having substantially the same shape as the magnet ;
A magnetic fluid held in at least the gap ;
Have
The magnetic fluid seal with bearing rolling elements, wherein the formation benzalkonium a nonmagnetic material of the bearing body. The magnetic fluid is
  An outer ring-side magnetic fluid held between the outer ring and the electrode plate and / or between the outer ring and the magnet;
  An inner ring-side magnetic fluid held between the inner ring and the pole plate and / or between the inner ring and the magnet;
  The bearing with a magnetic fluid seal according to claim 1. 3. The bearing with a magnetic fluid seal according to claim 1, wherein the electrode plate is positioned in a state of being recessed from an end surface of the outer ring and an end surface of the inner ring. 4. A step including a surface perpendicular to the axial direction is formed on an end surface of the inner ring, and a radial thickness of the perpendicular surface is formed by the step from the inner surface of the electrode plate on the inner ring side. The bearing with a magnetic fluid seal according to any one of claims 1 to 3, wherein the bearing is set larger than the gap to the inner edge. The bearing with a magnetic fluid seal according to claim 4, wherein the inner edge is positioned within a range of an axial thickness of the electrode plate.

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