JP4246565B2 - Manufacturing method of magnetic encoder - Google Patents

Description

This invention relates to a method of manufacturing a magnetic encoder employed in the rotation detecting device such as a bearing portion for rotation relative such as wheel bearings, for example, the rotation detecting device for detecting a wheel rotational speeds of the front and rear of an automobile anti-lock braking system The present invention relates to a method of manufacturing a magnetic encoder that is a component of a bearing seal to be mounted.

  Conventionally, the following structure is often used as an anti-skid rotation detection device for preventing automobile skid. That is, the rotation detection device is composed of a toothed rotor and a sensing sensor, and is generally arranged so as to be separated from the seal device for sealing the bearing and constitute one independent rotation detection device. . Such a conventional example has a structure in which a toothed rotor fitted to a rotating shaft is sensed and detected by a rotation detection sensor attached to a knuckle, and a bearing used is provided independently on the side thereof. Protected against intrusion of moisture or foreign matter by the sealed device.

  As another example, Patent Document 1 discloses a bearing seal having a rotation detection device for detecting wheel rotation for the purpose of reducing the mounting space of the rotation detection device and dramatically improving the sensing performance. A structure is shown in which an elastic member mixed with magnetic powder is circumferentially vulcanized and bonded in the radial direction of a slinger to be used, and magnetic poles are alternately arranged there.

  Further, in Patent Document 2, for the purpose of reducing the dimension in the axial direction, improving the degree of sealing between the rotating member and the fixed member, and enabling easy attachment, Is shown, and a rotary disk is attached to the rotary member, and a multi-polar coder is attached to the rotary disk. The coder used is made of an elastomer to which magnetic particles are added, and is a sealing means in which the side surface of the coder is substantially flush with the fixing member.

  A coder made of plastic (plastomer) containing magnetic powder or magnetic particles can be formed into a bowl using a mold suitable for the product shape, like conventional injection molding or compression molding. Or by forming the sheet by extrusion molding using a T-shaped die or sheet molding such as calendering, and making it into a product shape by punching, etc., and then adhesively fixing on a metal substrate with an adhesive or the like You may make it. In this case, the metal substrate may be assembled in advance in the mold as in the case of insert molding, and then the molten resin may be poured and the bonding process may be simultaneously processed.

Japanese Patent No. 2816783 JP-A-6-281018

However, each of the above magnetic encoders contains a magnetic powder in a multipolar magnet. On the other hand, when used for a bearing for an automobile, etc., it is placed in a harsh environment exposed to road surface salty mud water. Rust generation during long-term use becomes a problem. In particular, when the content of magnetic powder is increased for miniaturization, rust is likely to occur. Then, although it thought about carrying out the antirust process of the multi-pole magnet of a magnetic encoder, selection of an appropriate antirust material is difficult.
In addition, the elastomer or plastomer in which the multipolar magnet contains the magnetic powder as described above has various problems as described below. The thing made into the sintered compact which sintered the powder mixed with powder was proposed (Japanese Patent Application No. 2001-290300). When such a multipolar magnet is used, a rust prevention treatment according to the characteristics is required.

  Furthermore, the present applicant has also proposed that a rust preventive film of a clear high corrosion resistance paint is formed on the surface of a multipolar magnet (Japanese Patent Application No. 2003-012710). However, the application of a modified epoxy clear coating to a multipolar magnet by dipping or spraying requires that the film thickness be increased in order to satisfy the corrosion resistance required for undercar parts for automobiles. May be higher. Moreover, masking may be required, and the process may be complicated. Furthermore, in order to ensure the film thickness uniformity and flatness of the film formation surface, the process control width such as coating and baking during film formation is narrow, and the yield may be poor. In addition, in order to improve the corrosion resistance between the cored bar and the sintered body in a state where the multipolar magnet as a sintered body is crimped to the cored bar, an impregnation treatment with a modified epoxy clear paint is performed, or the sintered body Although single coating or sealing treatment may be performed, the cost increases and is not economical.

The purpose of this invention, a magnetic excellent corrosion resistance, long-term use of, there is no problem of rusting even in the use of harsh environments, and excellent in productivity, it is possible to manufacture a magnetic encoder that cost can be reduced Ru der to provide a production method of the encoder.

The method of manufacturing a magnetic encoder of the present invention, a multi-pole magnet formed with magnetic poles alternately in the circumferential direction, e Bei a core metal for supporting the multi-pole magnet, the multi-pole magnet the magnetic powder and the non-magnetic metal A method of manufacturing a magnetic encoder , which is a sintered body obtained by sintering powder mixed with powder, on at least one of the sintered body and the core metal, on the contact surface between the sintered body and the core metal A groove for electrodeposition coating penetration is provided, the multipolar magnet is fixed to the core metal by caulking the core metal, and an anticorrosive coating is applied to the sintered core metal integrated product in which the sintered body is fixed to the core metal. This anticorrosion coating is performed by electrodeposition coating. The surface of the sintered cored bar integrated product is electrochemically electrophoresed by applying current to the sintered cored bar integrated product immersed in water-soluble paint. In this electrodeposition coating process, the water-soluble electrodeposition paint is applied to the grooves by electrophoresis. Infested Te, then characterized by adhering said sintered body and the core in electrodeposition coating by drying and baking step. The term “clamping” as used in this specification refers to the entire process of clamping and fixing by applying plastic pressure and plastic deformation, and includes clamping by bending, staking, or the like.

  According to this configuration, the sintered cored bar integrated product, in which the sintered multi-pole magnet is fixed to the cored bar by caulking, has been subjected to anticorrosion surface treatment. Therefore, the magnetic encoder is free from the problem of rust even when used in harsh environments. Since the surface treatment is performed in the state of a sintered metal core integrated product, the number of processes is fewer than in the case where the surface treatment is individually performed, the productivity is excellent, and the cost can be reduced.

Since electrodeposition coating has better throwing power than coating-type coating, the entire surface of the sintered cored bar can be painted, which improves the corrosion resistance of the entire multi-pole magnet made of sintered body. it can. Also, in electrodeposition coating, the paint can easily enter the gap between the sintered body (multipolar magnet) and the cored bar, so an adhesion effect is obtained, and the multipolar magnet is firmly attached to the cored bar by both the caulking and bonding effects. Can be held. For example, even if caulking is loose, the adhesive effect can prevent the multipolar magnet from being separated from the cored bar, thereby improving the reliability of the product. Furthermore, since the electrodeposition coating can form a uniform coating film as compared with the coating method and the impregnation method, the size control of the magnetic encoder as a product can be easily performed.

  There are two types of electrodeposition coating: an anion type that makes the sintered core metal integrated product a positive electrode and a cation type that makes the negative electrode a negative electrode. A type of electrodeposition coating is more preferred.

Also, as described above, at least one of the above sintered body and the core, providing a groove for electrodeposition paint penetration at a contact surface between these sintered body and the core. When the groove is provided in this way, in the step of fixing the sintered body and the cored bar by caulking, and then performing electrodeposition, in the groove formed between the sintered body and the cored bar, The electrodeposition paint penetrates by electrophoresis, and then the sintered body and the core metal are bonded by a drying and baking process, and the adhesion between the sintered body and the core metal is further improved.

  The magnetic powder may be a samarium-based magnetic powder or a neodymium-based magnetic powder. When these samarium magnetic powder and neodymium magnetic powder are used, a strong magnetic force can be obtained. As the samarium magnetic powder, samarium iron (SmFeN) magnetic powder is used, and as the neodymium magnetic powder, neodymium iron (NdFeB) magnetic powder is used. In addition, the magnetic powder may be manganese aluminum (MnAl) gas atomized powder.

  The nonmagnetic metal powder may be tin powder. When the magnetic powder is ferrite powder, samarium-based magnetic powder, or neodymium-based magnetic powder, tin powder may be used as the non-magnetic metal powder.

  The mixed powder may contain two or more kinds of magnetic powders, or may contain two or more kinds of nonmagnetic metal powders. The mixed powder may contain two or more kinds of magnetic powders and may contain two or more kinds of nonmagnetic metal powders. When two or more kinds of magnetic powders or two or more kinds of metal powders are included, desired characteristics can be obtained by arbitrarily mixing a plurality of kinds of powders. For example, when the magnetic force is insufficient with only the ferrite powder, it is possible to manufacture the ferrite powder at a low cost while improving the magnetic force by mixing the samarium-based magnetic powder or the neodymium-based magnetic powder, which are rare earth-based magnetic materials, with a necessary amount.

The method for manufacturing a magnetic encoder according to the present invention can be applied to a magnetic encoder provided in a wheel bearing. Wheel bearings are generally exposed to road conditions, and the magnetic encoder may be subject to salty mud water, but the entire sintered metal core that constitutes the magnetic encoder has an anticorrosive surface treatment. Therefore, the effect of preventing the magnetic encoder from rusting due to salt water is high.
Further, particles such as sand particles may be caught between the magnetic encoder and the magnetic sensor facing the magnetic encoder. The following protection is provided against this biting. That is, the surface height of the sintered multipolar magnet made of magnetic powder and non-magnetic metal powder is harder than that of an elastic member or elastomer coder containing conventional magnetic powder or magnetic particles. For this reason, in a wheel bearing having a magnetic encoder for detecting wheel rotation, particles such as sand particles get caught in the gap between the surface of the rotating multipolar magnet and the surface of the stationary magnetic sensor during vehicle running. Even if rare, it has a significant reduction effect on wear damage of multipolar magnets.

The magnetic encoder manufacturing method of the present invention may be applied to a magnetic encoder that is a component of a seal device for sealing a bearing space in a wheel bearing . For example, this wheel bearing includes an outer member in which double-row rolling surfaces are formed on the inner peripheral surface, an inner member in which a rolling surface opposite to the rolling surface of the outer member is formed, A wheel bearing comprising a double row rolling element interposed between the rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, wherein the annular space between the outer member and the inner member It is assumed that a sealing device is provided for sealing. The component of this sealing device is a magnetic encoder. In this case, the magnetic seal device is opposed to the first seal plate having an L-shaped cross section fitted to the rotation-side member of the outer member or the inner member, and the first seal plate. A side lip that is slidably in contact with a standing plate portion of the first seal plate, and a cylinder, the second seal plate having an L-shaped cross section fitted to a fixed member of the outer member or the inner member A radial lip that is in sliding contact with the portion is fixed to the second seal plate, the first seal plate is a core metal in the magnetic encoder, and the multipole magnet is provided at least partially overlapping the standing plate portion. It may be.

  In the case of the wheel bearing of this configuration, since the component of the seal device is a magnetic encoder, the rotation of the wheel can be detected with a more compact configuration without increasing the number of parts. Further, when the magnetic encoder is configured in the sealing device in this way, there is a problem of biting of sand particles or the like between the magnetic encoder and the magnetic sensor due to exposure to the above road surface environment. As described above, since the surface height of the multipolar magnet is hard, an effect of reducing wear damage can be obtained. There is also an anti-corrosion effect by surface treatment for anti-corrosion. Further, in the case of this configuration, an excellent sealing effect can be obtained by the side lip and radial lip fixed to the second seal plate being in sliding contact with the first seal plate.

  The first seal plate has, for example, a substantially inverted Z-shaped cross section, and includes a fitting-side cylindrical portion, a standing plate portion, and another cylindrical portion that are fitted to the rotation-side member. May be. When the seal plate has a substantially inverted Z-shaped cross section, the other cylindrical portion can be used for caulking and fixing the sintered body, and the caulking and fixing of the sintered body can be performed more easily.

When the first seal plate has a substantially inverted Z-shape or L-shape in cross section, the following configurations may be employed. However, what uses an outer peripheral side cylindrical part is applied only to what was made into the cross-section substantially reverse Z shape.
The upright plate portion of the first seal plate may have a two-stage shape in which the inner peripheral portion and the outer peripheral portion are displaced from each other in the axial direction.
-You may fix the said multipolar magnet to the standing-plate part of a 1st sealing board by crimping of the outer peripheral side cylindrical part of a 1st sealing board.
A multipolar magnet provided with plastic deformation portions plastically deformed in a protruding state toward the inner diameter side at a plurality of locations in the circumferential direction of the outer cylindrical portion of the first seal plate and superimposed on the standing plate portion of the first seal plate May be crimped and fixed by the plastic deformation portion.
-You may fix the said multipolar magnet to the standing-plate part of a 1st sealing board by the plastic deformation of the nail | claw-shaped protrusion provided in the outer peripheral part of the 1st sealing board.

The method of manufacturing a magnetic encoder of the present invention, a multi-pole magnet formed with magnetic poles alternately in the circumferential direction, e Bei a core metal for supporting the multi-pole magnet, the multi-pole magnet the magnetic powder and the non-magnetic metal A method for producing a magnetic encoder which is a sintered body obtained by sintering powder mixed with powder ,
At least one of the sintered body and the cored bar is provided with a groove for intrusion of electrodeposition paint on the contact surface between the sintered body and the cored bar, and the multipolar magnet is attached to the cored bar by caulking the cored bar. An anticorrosion coating is applied by electrodeposition coating to a sintered body cored bar integrated product in which this sintered body is fixed to a core metal , and this anticorrosion coating electrodeposition coating is a sintered body immersed in a water-soluble paint. In this method, a current is passed through the cored bar product and an anticorrosive film is electrochemically applied to the surface of the sintered cored bar united product by electrophoresis. In this electrodeposition coating process, the water-soluble electrode is placed in the groove. Adhesive coating is infiltrated by electrophoresis, and then the sintered body and the metal core are bonded together by electrodeposition coating in a drying / baking process. Therefore, it has excellent corrosion resistance and can be used for long-term use and in harsh environments. It generates no problem, and excellent productivity, manufacturing a magnetic encoder cost can be reduced Effect there Ru that it can be. In the electrodeposition coating, at least one of the sintered body and the cored bar is provided with a groove for electrodeposition coating penetration at the contact surface between the sintered body and the cored bar, and the water-soluble electrodeposition is formed in the groove. Since the paint is infiltrated by electrophoresis, and then the sintered body and the core metal are adhered by the electrodeposition paint in the drying and baking process, the adhesion between the sintered body and the core metal is improved.

  A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the magnetic encoder 10 includes a metal annular cored bar 11 and a multipolar magnet 14 provided on the surface of the cored bar 11 along the circumferential direction. The multipolar magnet 14 is a member that is magnetized in multiple poles in the circumferential direction and has magnetic poles N and S alternately formed, and is composed of a magnetic disk magnetized in multiple poles. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle diameter PCD (FIG. 2). The multipolar magnet 14 is a sintered body obtained by sintering a green compact of powder mixed with magnetic powder and nonmagnetic metal powder. The multipolar magnet 14 is attached to the core metal 11 by crimping the core metal 11. Fix it. An anticorrosive coating 22 is applied as a surface treatment for anticorrosion to the sintered core metal integrated product 21 in which the sintered body is fixed to the metal core 11. The magnetic encoder 10 is attached to a rotating member (not shown), and is used for rotation detection with a magnetic sensor 15 facing a multipolar magnet 14 as shown in FIG. The rotation detection device 20 is configured with the sensor 15. This figure shows an application example in which the magnetic encoder 10 is a component of a seal device 5 for a bearing (not shown), and the magnetic encoder 10 is attached to a bearing ring on the rotation side of the bearing. The seal device 5 includes a magnetic encoder 10 and a fixed-side seal member 9. A specific configuration of the sealing device 5 will be described later.

  The magnetic powder mixed in the multipolar magnet 14 may be isotropic or anisotropic ferrite powder such as barium-based and strontium-based. These ferrite powders may be granular powders or pulverized powders composed of a wet anisotropic ferrite core. When the pulverized powder made of this wet anisotropic ferrite core is used as a magnetic powder, it is necessary to use a mixed powder with a nonmagnetic metal powder as an anisotropic green body formed in a magnetic field.

  The magnetic powder may be a rare earth magnetic material. For example, samarium iron (SmFeN) magnetic powder and neodymium iron (NdFeB) magnetic powder, which are rare earth magnetic materials, may be used alone. The magnetic powder may be manganese aluminum (MnAl) gas atomized powder.

  The magnetic powder may be a mixture of two or more of samarium iron (SmFeN) magnetic powder, neodymium iron (NdFeB) magnetic powder, and manganese aluminum (MnAl) gas atomized powder. For example, the magnetic powder is a mixture of samarium iron (SmFeN) magnetic powder and neodymium iron (NdFeB) magnetic powder, a mixture of manganese aluminum gas atomized powder and samarium iron magnetic powder, and samarium iron. Any of a mixture of a system magnetic powder, a neodymium iron system magnetic powder, and a manganese aluminum gas atomized powder may be used. For example, when the magnetic force is insufficient with ferrite powder alone, the ferrite powder is mixed with the required amount of rare earth magnetic material samarium iron (SmFeN) magnetic powder or neodymium iron (NdFeB) magnetic powder to improve the magnetic force. It can also be manufactured at low cost.

  The non-magnetic metal powder forming the multipolar magnet 14 may be a powder of tin, copper, aluminum, nickel, zinc, tungsten, manganese, or a non-magnetic stainless steel metal powder alone (one type). Body, a mixed powder composed of two or more kinds, or an alloy powder composed of two or more kinds can be used.

  The metal that is the material of the core metal 11 is preferably a magnetic material, particularly a metal that is a ferromagnetic material. For example, a steel plate that is magnetic and has rust prevention properties is used. As such a steel plate, a ferritic stainless steel plate (JIS standard SUS430 series or the like), a rust-proof rolled steel plate, or the like can be used.

  The shape of the core metal 11 can be various annular shapes, but a shape capable of fixing the multipolar magnet 14 is preferable. In particular, a shape capable of performing mechanical fixing such as caulking and fitting fixing is preferable. In the case of caulking and fixing, for example, as shown in FIG. 1B, the core metal 11 includes an inner diameter side cylindrical portion 11a serving as a fitting side, an upright plate portion 11b extending from one end to the outer diameter side, The cross section formed by the other cylindrical portion 11c of the diameter edge is a substantially inverted Z-shaped annular shape. The cored bar 11 may have an L-shaped cross section, and in that case, the cored bar 11 in FIG. 1B has a shape in which the other cylindrical portion 11c is omitted. When the metal core 11 has an L-shaped cross section, for example, a claw portion or the like is provided on the upright plate portion 11b or the like and fixed by caulking.

  In the cored bar 11 of FIG. 1B, the cylindrical portion 11a, the standing plate portion 11b, and the other cylindrical portion 11c are integrally press-formed from a metal plate such as a steel plate. The standing plate portion 11b is formed flat, and a non-magnetized sintered body of the multipolar magnet 14 is built on the surface of the flat standing plate portion 11b, and the other cylindrical portion 11c of the outer peripheral edge is crimped. Thus, the multipolar magnet 14 is fixed in an overlapping state on the standing plate portion 11 b of the core metal 11, and the sintered core metal integrated product 21 is obtained. In the other cylindrical portion 11c, a tip side portion or substantially the whole in the cross section serves as a crimped portion. Further, the caulking portion extends over the entire circumference of the core metal 11 and thus has an annular shape. In addition, the part fixed by the other cylindrical part 11c of the multipolar magnet 14 becomes the recessed part 14b dented rather than the surface used as the to-be-detected surface of the multipolar magnet 14, Thereby, the plastic deformation part 11ca becomes a multipolar magnet. 14 so as not to protrude from the surface to be detected.

  The caulking and fixing may be performed as shown in the sectional view and the front view in FIGS. In this example, the cored bar 11 has a cylindrical portion 11a on the inner diameter side, a standing plate portion 11b extending from one end thereof to the outer diameter side, and a cylindrical other cylindrical portion 11c on the outer diameter edge, as in the example of FIG. The cross section is generally an inverted Z-shaped ring. In addition, a plastic deformation portion 11ca that is plastically deformed in a protruding state toward the inner diameter side by staking or the like is provided at a plurality of circumferential positions in the other cylindrical portion 11c, and the multipolar magnet 14 is attached to the core metal 11 by the plastic deformation portion 11ca. Are fixed to the standing plate portion 11b. Also in this example, the portion fixed by the plastic deformation portion 11ca of the multipolar magnet 14 is a dent portion 14b that is recessed from the surface of the multipolar magnet 14 that becomes the detection surface, whereby the plastic deformation portion 11ca is The multipolar magnet 14 is configured not to protrude from the surface to be detected. The recessed portion 14b is formed as an inclined surface 14b that approaches the rear surface side from the front surface as it reaches the outer diameter side.

  In each example shown in FIG. 1 and FIG. 4, the cored bar 11 has a two-stage shape in which the standing plate portion b is shifted in the axial direction between the inner peripheral portion 11 ba and the outer peripheral portion 11 bb as shown in FIG. 6. It can also be made. In FIG. 6, although not shown, the multipolar magnet 14 is disposed on the protruding side surface of the other cylindrical portion 11 c in the standing plate portion 11 b as in the example of FIG. 1.

  Further, as shown in FIG. 7, in the metal core 11 having a substantially inverted Z-shaped cross section similar to the example of FIG. 1, tongue-like claw portions are provided at a plurality of circumferential positions on the edge of the other cylindrical portion 11c. The multipolar magnet 14 may be fixed to the metal core 11 by providing 11 cb and plastically deforming the tongue-like claw portion 11 cb toward the inner diameter side as shown by an arrow, that is, by crimping it so as to be bent. The multipolar magnet 14 is disposed on the protruding side surface of the other cylindrical portion 11c in the upright plate portion 11b as in the example of FIG. Also in this example, like the example of FIG. 6, the standing plate portion 11b has a two-stage shape. When the standing plate portion 11b has a two-stage shape, the side shape on the standing plate portion 11b side of the multipolar magnet 14 is a side shape along the two-step shape of the standing plate portion 11b as shown in FIG. It is also good.

  As in each of the above examples, the magnetic encoder 10 is configured by applying the anticorrosion film 22 by the electrodeposition method on the surface of the sintered cored bar integrated product 21 formed by crimping and fixing the multipolar magnet 14 to the cored bar 11. Is done. In this case, the electrodeposition coating of the anticorrosion film 22 applies an electric current to the sintered cored bar integrated product 21 immersed in the water-soluble paint, and electrochemically applied to the surface of the sintered cored bar integrated product 21 by electrophoresis. The anticorrosion film 22 is applied. The electrodeposition coating is roughly classified into two types: anion electrodeposition coating in which the sintered core metal integrated product 21 is a positive electrode and cationic electrodeposition coating in which the sintered core metal integrated product 21 is a negative electrode. . When the encoder 10 is mounted on a wheel bearing, corrosion resistance is required, and therefore, the anticorrosion film 22 is preferably applied by cationic electrodeposition coating. The moisture content of the anticorrosion coating 22 which is an electrodeposition coating applied by the electrodeposition coating is about 10% or less, and drying and baking are performed to form a final coating.

  The characteristics of the above-mentioned electrodeposition coating are that the uniform film thickness is better than solvent coating, and the throwing power is good, so even products with large irregularities can be uniformly coated on the entire surface. If the masking technique is used, two-color coating can be easily performed by using electrodeposition coating and plating together or by repeating electrodeposition coating twice. For this reason, the coating performance of the end face part, which is not easy to paint with the existing modified epoxy clear coating applied by dipping (spraying) method or spraying (spraying) method, is greatly improved by the above electrodeposition coating. To do. Further, in the electrodeposition coating, the coating material is sintered in the sintered body cored product 21 due to the electrophoretic coating of the sintered body crimping portion and the inner diameter side end surface portion due to electrophoresis and penetration. Since it acts as an adhesive between the pole magnet 14) and the metal core 11, it is a sintered body compared with the case where an existing modified epoxy clear coating is applied by dipping (spraying) or spraying (spraying). Adhesion between the (multipolar magnet 14) and the cored bar 11 is greatly improved.

  Further, in order to improve the adhesion between the sintered body (multipolar magnet 14) and the cored bar 11 in the sintered cored bar integrated product 21, for example, as shown in FIGS. It is good also as what has the groove | channels 23 and 24 which accept | permit the penetration | invasion of water-soluble electrodeposition coating material in the back surface (surface which contact | connects the metal core 11) of the pole magnet 14). In the example of FIG. 8, a plurality of radial grooves 23 extending in the radial direction are formed, and in the example of FIG. 9, the plurality of radial grooves 23 and the sintered body (multipolar magnet 14) are concentric with the above. A ring-shaped groove 24 intersecting with the radial groove 23 is formed.

  Thus, by forming the grooves 23 and 24 on the back surface of the sintered body (multipolar magnet 14), the water-soluble electrodeposition paint is electrophoresed in the grooves 23 and 24 in the electrodeposition coating process. The sintered body (multipolar magnet 14) and the cored bar 11 can be adhered with an electrodeposition paint by intrusion and subsequent drying and baking processes.

  8 and 9 show the case where the grooves 23 and 24 are formed on the back surface of the sintered body (multipolar magnet 14). However, the present invention is not limited to this, as shown in FIGS. You may form the groove | channel 25,25A, 26 which accept | permits the penetration | invasion of water-soluble electrodeposition coating material from the standing plate part 11b or the standing plate part 11b of the gold | metal | money 11 to the other cylindrical part 11c. In the example of FIG. 10, a plurality of radial grooves 25 extending in the radial direction are formed by pressing or cutting on the surface of the standing plate portion 11 b that contacts the sintered body (multipolar magnet 14). In the example of FIG. 11, a plurality of radial grooves 25A extending from the standing plate portion 11b to the other cylindrical portion 11c are formed by pressing or cutting. In the example of FIG. 12, a plurality of radial grooves 25 and a ring-shaped groove 26 that is concentric with the core metal 11 and intersects the radial grooves 25 are formed in the standing plate portion 11 b by pressing or cutting.

  As described above with reference to FIG. 3, the magnetic encoder 10 having this configuration is used for rotation detection with the magnetic sensor 15 facing the multipolar magnet 14. When the magnetic encoder 10 is rotated, the magnetic sensor 15 detects the passage of the magnetic poles N and S magnetized in the multipole of the multipolar magnet 14, and the rotation is detected in the form of pulses. The pitch p (FIG. 2) of the magnetic poles N and S can be set finely. For example, it is possible to obtain an accuracy that the pitch p is 1.5 mm and the pitch difference is ± 3%, thereby enabling highly accurate rotation detection. The pitch mutual difference is a value indicating a difference in distance between the magnetic poles detected at a position away from the magnetic encoder 10 by a predetermined distance as a ratio to the target pitch. When the magnetic encoder 10 is applied to the bearing seal device 5 as shown in FIG. 3, the rotation of the bearing to which the magnetic encoder 10 is attached is detected.

  This magnetic encoder 10 has excellent corrosion resistance because the sintered cored bar integrated product 21 in which the multipolar magnet 14 as a sintered body is fixed to the cored bar 11 by caulking is subjected to a surface treatment for corrosion protection. It is a magnetic encoder that does not have the problem of rusting even in long-term use or in severe environments. For example, it can be used in an environment where rust is easily generated, such as a wheel bearing.

  In addition, since the multipolar magnet 14 is made of a sintered body mixed with magnetic powder, the magnetic encoder 10 can be made thin while securing a magnetic force for obtaining stable sensing as shown below, and the magnetic encoder 10 can be made compact. In addition, it has excellent wear resistance and excellent productivity.

  Furthermore, the surface height of the multipolar magnet 14 is harder than that of a conventional elastic member or elastomer coder containing magnetic powder or magnetic particles. For this reason, when applied to the rotation detection device 20 for detecting wheel rotation, particles such as sand particles bite into the gap between the surface of the multipolar magnet 14 on the rotating side and the surface of the magnetic sensor 15 on the fixed side while the vehicle is running. Even if it is inserted, wear damage of the multipolar magnet 14 hardly occurs, and there is a significant reduction effect of wear as compared with a conventional elastic body.

The particularly characteristic advantages of this embodiment are summarized as follows.
-Since electrodeposition coating has better throwing power than coating-type coating, the entire product can be painted, so that the corrosion resistance of the entire sintered body (multipolar magnet 14) can be improved.
・ Since electrodeposition coating has better throwing power than coating-type coating, it is easy to enter the gap between the sintered body (multi-pole magnet 14) and the cored bar 11. The sintered body and the metal core can be held by both “adhesion” and “adhesion”. Even if the caulking is loose, separation can be prevented by the adhesive effect, so that the reliability of the product is improved.
-Electrodeposition coating can form a uniform coating film compared to the coating method, making product dimensional control easier.
-The adhesiveness of a sintered compact and a core metal can be improved by providing a dent in at least any one of a sintered compact (multipolar magnet 14) or a core metal (11).

  Next, the test results of the corrosion resistance performance of the anticorrosion film 22 by the electrodeposition coating will be described together with Table 1. The test was conducted for each sample to be Examples 1 to 10 and Comparative Examples 1 to 10 according to the above embodiment. In the above samples, as the magnetic powder constituting the sintered multi-pole magnet 14, samarium iron (Sm-Fe-N) magnetic powder and neodymium iron (Nd-Fe-B) magnetic powder are used. The one using was prepared. The binder was all Sn. Which magnetic powder was used and the blending ratio are shown in Table 1. With this blending ratio, a green body (unsintered green compact) of φ54 mm × φ66 mm × 1.5 mm was molded with a pressure press and fired in the air for 1 hour. The shapes of the sintered body (multipolar magnet 14) and the cored bar 11 of each sample are the shapes shown in FIG. In each sample used in Examples 1 to 10, the above-described various electrodeposition coatings were performed on these sintered cored bar integrated products 21 to form a rust preventive film 22. On the other hand, in each sample of Comparative Examples 1 to 10, various coatings such as epoxy coating and epoxy impregnation were performed.

The following tests were performed on each of these samples.
(1) About each sample, NaCl heated at 55 degreeC was immersed in 5% solution for 24 hours, and the corrosion resistance was compared. Table 1 shows marks of ◎, ○, Δ, and × in order of excellent corrosion resistance.
(2) When the above samples, which are rust-proofed products, are used as products, the flatness of the surfaces of the sintered body (multipolar magnet 14) and the cored bar 11 is important. The detection sensitivity of the detection device 20 may deteriorate, which is not preferable. From this point of view, the surface shape was measured, and when the surface roughness Rz, which is the measurement result, was 50 μm or less, it was shown in Table 1 as ○, and when it was larger than 50 μm, it was marked as x.
(3) In order to evaluate the adhesion between the sintered body (multipolar magnet 14) and the cored bar 11, an iron jig was inserted into the gap between the sintered body and the cored bar 11 and was forcibly separated. When the adhesion is good, it does not peel off at the interface between the sintered body (multipolar magnet 14) and the cored bar 11, and breaks inside the sintered body, so that the amount of the coating film fixed on the surface of the cored bar 11 is large. In Table 1, ◎, ○, △, × marks are also shown in descending order of adhesion amount.

Each example in Table 1 is an example showing details in the following, and the following matters can be understood from the test results shown in Table 1.
Example 1: Sm-Fe-N magnetic material was used for the sintered body (multipolar magnet 14), and cation electrodeposition was performed on the sintered body and the sintered core metal integrated product 21 in which no groove was formed in the core metal 11. Went. This example was excellent in all of corrosion resistance, flatness and adhesion.
Example 2 An Sm—Fe—N magnetic material was used for the sintered body (multipolar magnet 14), and anion electrodeposition was applied to the sintered body and the cored metal integrated product 21 having no grooves in the cored bar 11. Went. In this example, although the corrosion resistance was slightly inferior to that in the case of cationic electrodeposition, the flatness and adhesion were excellent.
Example 3 Cationic electrodeposition on a sintered body and a cored bar integrated product 21 in which a groove is not formed in the sintered body and the cored bar 11 using a Nd-Fe-B based magnetic body as a sintered body (multipolar magnet 14). Went. This example was excellent in all of corrosion resistance, flatness and adhesion.
Examples 4 to 10: Cationic electrodeposition was performed on a sintered core metal integrated product 21 in which a groove was formed in one or both of the sintered body (multipolar magnet 14) and the core metal 11. In each of these examples, all were excellent in corrosion resistance, flatness, and adhesion. In particular, the adhesion was very excellent.
Comparative Example 1: For a sintered body cored bar integrated product 21 in which a sintered body and a cored bar 11 are not grooved using an Sm-Fe-N based magnetic body as a sintered body (multipolar magnet 14), An epoxy clear coating film was coated and baked at 180 ° C. for 20 minutes. In this example, although the corrosion resistance of the sintered compact surface was favorable, the corrosion resistance of the inner diameter part which is hard to adhere was inferior. The flatness was good, but the adhesion was poor.
Comparative Example 2: For a sintered body cored bar integrated product 21 in which a sintered body and the cored bar 11 are not grooved using an Sm-Fe-N based magnetic body as a sintered body (multipolar magnet 14), Epoxy clear (Tokyo Paint: TPR-RC clear) is diluted with thinner, and the sintered compact is immersed in the diluted solution and evacuated, and the gap between the sintered compact and the core metal 11 is forcibly impregnated with resin. After holding for a certain period of time, the sintered body was taken out and baked at 180 ° C. for 20 minutes. In this example, the corrosion resistance was good, but the flatness was inferior, and the adhesion was also inferior to that of the electrodeposition coating.
Comparative example 3: Nd-Fe-B based magnetic body is used for the sintered body (multi-pole magnet 14), and the sintered body and the cored bar integrated product 21 in which the groove is not formed in the cored bar 11, Epoxy clear (Tokyo Paint: TPR-RC clear) is diluted with thinner, and the sintered body is immersed in the diluted solution and evacuated, and the gap between the sintered body and the core 11 is forcibly impregnated with resin. After holding for a certain period of time, the sintered body was taken out and baked at 180 ° C. for 20 minutes. In this example, the corrosion resistance was good, but the flatness was inferior, and the adhesion was also inferior to that of the electrodeposition coating.
Comparative Examples 4 to 10: Sintered body core using a sintered body (multipolar magnet 14) with an Sm-Fe-N-based magnetic body and a groove formed in one or both of the sintered body and the cored bar 11. An epoxy clear (Tokyo Paint: TPR-RC clear) is diluted with a thinner with respect to the gold integrated product 21, and the sintered body is immersed in the diluted solution to perform vacuuming. After the resin was forcibly impregnated in the gap and held for a certain time, the sintered body was taken out and baked at 180 ° C. for 20 minutes. In these examples, the corrosion resistance was good, but the flatness was poor, and the adhesion was also inferior to that of the electrodeposition coating.

  Next, an example of a wheel bearing provided with the magnetic encoder 10 and an example of the seal device 5 will be described with reference to FIGS. As shown in FIG. 13, the wheel bearing includes an inner member 1 and an outer member 2, a plurality of rolling elements 3 accommodated between the inner and outer members 1 and 2, and the inner and outer members 1 and 2. Sealing devices 5 and 13 for sealing the end annular space. The sealing device 5 at one end is provided with a magnetic encoder 10. The inner member 1 and the outer member 2 have raceway surfaces 1a and 2a of the rolling element 3, and each raceway surface 1a and 2a is formed in a groove shape. The inner member 1 and the outer member 2 are an inner peripheral member and an outer peripheral member that are rotatable with respect to each other via the rolling elements 3, respectively. An assembly member in which the bearing inner ring and the bearing outer ring are combined with another component may be used. Further, the inner member 1 may be a shaft. The rolling element 3 consists of a ball or a roller, and a ball is used in this example.

  This wheel bearing is a double-row rolling bearing, more specifically, a double-row angular contact ball bearing, and the inner ring of the bearing is a pair of split type in which the raceway surfaces 1a and 1a of the respective rolling element rows are respectively formed. It consists of inner rings 18 and 19. The inner rings 18 and 19 are fitted to the outer periphery of the shaft portion of the hub ring 6 and constitute the inner member 1 together with the hub ring 6. The inner member 1 is integrated with the hub ring 6 and one inner ring 18 instead of the three-piece assembly part including the hub ring 6 and the pair of split inner rings 18 and 19 as described above. It is good also as what consists of two components comprised by the hub ring with a raceway surface and the other inner ring | wheel 19. FIG.

  One end (for example, an outer ring) of the constant velocity universal joint 7 is connected to the hub wheel 6, and a wheel (not shown) is attached to the flange portion 6 a of the hub wheel 6 with a bolt 8. The other end (for example, inner ring) of the constant velocity universal joint 7 is connected to the drive shaft. The outer member 2 includes a bearing outer ring, and is attached to a housing (not shown) including a knuckle or the like in the suspension device. The rolling elements 3 are held by a holder 4 for each row.

  FIG. 14 shows an enlarged view of the sealing device 5 with a magnetic encoder. The sealing device 5 is the same as that shown in FIG. 3 and a part of the sealing device 5 has been described above, but the details will be described with reference to FIG. The sealing device 5 is attached to a rotating member of the inner member 1 and the outer member 2 with the magnetic encoder 10 or its core 11 serving as a slinger. In this example, since the member on the rotation side is the inner member 1, the magnetic encoder 10 is attached to the inner member 1.

  This sealing device 5 has annular sealing plates (11), 12 made of first and second metal plates attached to the inner member 1 and the outer member 2, respectively. The first seal plate (11) is the core metal 11 in the magnetic encoder 10 and will be described as the core metal 11 below. The magnetic encoder 10 is according to the first embodiment described above with reference to FIGS. 1 to 3, and redundant description thereof is omitted. The rotation detection device 20 for detecting the wheel rotation speed is configured by arranging the magnetic sensor 15 as shown in the figure so as to face the multipolar magnet 14 in the magnetic encoder 10.

  The second seal plate 12 is a member constituting the seal member 9 (FIG. 3), and slides on the side lip 16a and the cylindrical portion 11a that are in sliding contact with the upright plate portion 11b of the core metal 11 that is the first seal plate. Radial lips 16b and 16c that are in contact with each other are integrally provided. The lips 16 a to 16 c are provided as a part of the elastic member 16 that is vulcanized and bonded to the second seal plate 12. The number of the lips 16a to 16c may be arbitrary, but in the example of FIG. 14, one side lip 16a and two radial lips 16c and 16b positioned inside and outside in the axial direction are provided. The second seal plate 12 is configured such that an elastic member 16 is held in a fitting portion with the outer member 2 that is a fixed side member. That is, the elastic member 16 has a tip cover portion 16d that covers from the inner diameter surface of the cylindrical portion 12a to the outer diameter of the tip portion, and this tip cover portion 16d is formed between the second seal plate 12 and the outer member 2. Intervenes in the fitting part. The cylindrical portion 12a of the second seal plate 12 and the other cylindrical portion 11c of the core metal 11 serving as the first seal plate are opposed to each other with a slight radial gap, and the labyrinth seal 17 is configured by the gap.

  According to the wheel bearing of this configuration, the rotation of the inner member 1 rotating together with the wheel is detected by the magnetic sensor 15 via the magnetic encoder 10 attached to the inner member 1, and the wheel rotation speed is detected. The

  Since the magnetic encoder 10 is a constituent element of the sealing device 5, the rotation of the wheel can be detected without increasing the number of parts. The wheel bearing is generally exposed to the road surface environment, and the magnetic encoder 10 may be covered with salt mud water. However, the sintered cored bar integrated product 21 constituting the magnetic encoder 10 has an anticorrosive property as a whole. Since the surface treatment is performed, it is possible to reliably prevent the magnetic encoder 10 from being rusted by the salt mud water. Further, particles such as sand particles may be caught between the magnetic encoder 10 and the magnetic sensor 15 facing the magnetic encoder 10, but as described above, the multipolar magnet 14 of the magnetic encoder 10 is made of a sintered body. Since it is hard, wear damage on the surface of the multipolar magnet 14 is greatly reduced as compared with a conventional elastic body.

  As for the seal between the inner and outer members 1 and 2, the first seal plate is used for sliding contact of the seal lips 16 a to 16 c provided on the second seal plate 12 and the cylindrical portion 12 a of the second seal plate 12. It is obtained with the labyrinth seal 17 constituted by the other cylindrical portion 11c of a certain core metal 11 facing each other with a slight radial gap.

In the wheel bearings shown in FIGS. 13 and 14, the core bar 11 of the magnetic encoder 10 is shown as having the shape of FIG. 1, but the magnetic encoder 10 is shown in FIGS. 4 to 7. Each example may be used.
Further, when the magnetic encoder 10 is used as a component of the bearing seal device 5, the multipolar magnet 14 may be provided inward with respect to the bearing, contrary to the above embodiments. That is, the multipolar magnet 14 may be provided on the inner surface of the bearing of the core metal 11. In that case, the cored bar 11 is preferably made of a non-magnetic material.
Further, in a wheel bearing in which the outer member is a rotating member, a magnetic encoder is attached to the outer member.

(A) is a partial perspective view of the magnetic encoder of the method for manufacturing a magnetic encoder that written to the first embodiment will be applied to the present invention, is a partial perspective view showing the assembly process of the magnetic encoder (B) . It is explanatory drawing of the magnetic pole which shows the same magnetic encoder from the front. It is a partial fracture front view showing a sealing device provided with the magnetic encoder and a magnetic sensor. It is a perspective view which shows the back surface of an example of the multipolar magnet in the magnetic encoder. It is a perspective view which shows the back surface of the other example of the multipolar magnet in the same magnetic encoder. It is a fragmentary perspective view which shows an example of the metal core in the magnetic encoder. It is a fragmentary perspective view which shows the other example of the metal core in the magnetic encoder. It is a fragmentary perspective view which shows the other example of the metal core in the magnetic encoder. It is a fragmentary perspective view of the magnetic encoder concerning other embodiment of this invention. It is a front view of the magnetic encoder. It is a fragmentary sectional view of the modification of a metal core. (A), (B) is another partial perspective view of the other modification of a metal core, and the magnetic encoder using the metal core, respectively. It is a cross-sectional view of the entire wheel bearing having a magnetic encoder manufactured by the manufacturing method of the magnetic encoder that written to the first embodiment. It is a fragmentary sectional view of the bearing for the wheels.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner member 2 ... Outer member 3 ... Rolling body 5 ... Sealing device 10 ... Magnetic encoder 11 ... Core metal (1st sealing board)
11a ... Cylindrical portion 11b ... Standing plate portion 11c ... Other cylindrical portion 12 ... Second seal plate 14 ... Multipolar magnet 15 ... Magnetic sensor 16a ... Side lip 16b, 16c ... Radial lip 20 ... Rotation detector 21 ... Sintered body Core metal integrated product 22 ... Anti-corrosion coating

Claims (13)

And multipolar magnets forming the pole alternately in the circumferential direction, e Bei a core metal for supporting the multi-pole magnet, the multi-pole magnet is by sintering mixed powder of a magnetic powder and a nonmagnetic metal powder A method of manufacturing a magnetic encoder that is a sintered body ,
At least one of the sintered body and the cored bar is provided with a groove for intrusion of electrodeposition paint on the contact surface between the sintered body and the cored bar, and the multipolar magnet is attached to the cored bar by caulking the cored bar. An anticorrosion coating is applied by electrodeposition coating to a sintered body cored bar integrated product in which this sintered body is fixed to a core metal , and this anticorrosion coating electrodeposition coating is a sintered body immersed in a water-soluble paint. In this method, a current is passed through the cored bar product and an anticorrosive film is electrochemically applied to the surface of the sintered cored bar united product by electrophoresis. In this electrodeposition coating process, the water-soluble electrode is placed in the groove. A method of manufacturing a magnetic encoder , comprising: adhering a coating material by electrophoresis, and then bonding the sintered body and the cored bar with an electrodeposition coating material through a drying and baking process . 2. The method of manufacturing a magnetic encoder according to claim 1, wherein the electrodeposition coating is cationic electrodeposition. 3. The method of manufacturing a magnetic encoder according to claim 1, wherein the magnetic powder is a samarium-based magnetic powder . 4. The method of manufacturing a magnetic encoder according to claim 1, wherein the magnetic powder is a neodymium-based magnetic powder. 5. The method of manufacturing a magnetic encoder according to claim 1, wherein the nonmagnetic metal powder is tin powder. 6. The method of manufacturing a magnetic encoder according to claim 1, wherein the mixed powder includes two or more kinds of magnetic powders or two or more kinds of nonmagnetic metal powders. 7. The method of manufacturing a magnetic encoder according to claim 1, wherein the magnetic encoder is used for a wheel bearing. 8. The wheel bearing according to claim 7, wherein the wheel bearing includes an outer member having a double row rolling surface formed on an inner peripheral surface, and an inner member formed with a rolling surface facing the rolling surface of the outer member. A double-row rolling element interposed between both rolling surfaces, and a wheel bearing for rotatably supporting the wheel with respect to the vehicle body,
A sealing device that seals the annular space between the outer member and the inner member is provided, and the sealing device has an L-shaped cross section that is fitted to the rotating side member of the outer member or the inner member. The first seal plate and the second seal plate facing the first seal plate and fitted to the fixed member of the outer member or the inner member, and having an L-shaped cross section, The side lip slidably contacting the upright plate portion of the first seal plate and the radial lip slidably contacting the cylindrical portion are fixed to the second seal plate, and the first seal plate serves as a core metal in the magnetic encoder, the multi-pole magnet is Ru provided superposed on the standing portion,
Manufacturing method of magnetic encoder. 8. The wheel bearing according to claim 7, wherein the wheel bearing includes an outer member having a double row rolling surface formed on an inner peripheral surface, and an inner member formed with a rolling surface facing the rolling surface of the outer member. A double-row rolling element interposed between both rolling surfaces, and a wheel bearing for rotatably supporting the wheel with respect to the vehicle body,
A sealing device for sealing an annular space between the outer member and the inner member is provided, and this sealing device has a substantially inverted Z cross-section fitted to the rotating side member of the outer member or the inner member. A first seal plate having a letter shape, and a second seal plate having an L-shaped cross section facing the first seal plate and fitted to the fixed member of the outer member or the inner member. The side lip that is in sliding contact with the upright plate portion of the first seal plate and the radial lip that is in sliding contact with the cylindrical portion are fixed to the second seal plate, and the first seal plate is a core metal in the magnetic encoder. next, the multipolar magnet is that provided overlapping on the standing portion,
Manufacturing method of magnetic encoder . 10. The method of manufacturing a magnetic encoder according to claim 9, wherein the upright plate portion on which the multipolar magnets of the first seal plate are stacked has a two-stage shape in which the inner peripheral portion and the outer peripheral portion are displaced from each other in the axial direction. . The method of manufacturing a magnetic encoder according to claim 9 or 10, wherein the multipolar magnet overlaid on the standing plate portion of the first seal plate is fixed by caulking the outer peripheral side cylindrical portion of the first seal plate. In Claim 9 or Claim 10 , the plastic deformation part which carried out the plastic deformation to the inner diameter side is provided in the peripheral direction cylindrical part in the 1st seal board in the peripheral direction, and it stands in the 1st seal board. A method of manufacturing a magnetic encoder in which a multipolar magnet overlaid on a plate portion is crimped and fixed by the plastic deformation portion . According to claim 9 or claim 10, magnetism above the multi-pole magnet superimposed on the standing portion of the first sealing plate, and fixed by plastic deformation of the claw-like projection provided on the outer peripheral cylindrical portion of the first sealing plate Encoder manufacturing method .

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