JP2005337318A - Cover for bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover for a bearing unit which is excellent in heat resisting properties and capable of reliably preventing fall-off from the outer ring member, improving production efficiency and reducing weight. <P>SOLUTION: The cover for a bearing unit is constituted of a cover element 11 made of a molded product of a resin material containing 35-60 wt% of glass fiber with polyamide resin as a matrix material. Further, the cover is provided with a disc-like closing plate part 20 situated in a mode that an end part opening 2a of an outer ring member 2 is closed; and a cylindrical fitting-in part 30 protruded to the internal surface of the closing plate part 20 and fitted in the inner peripheral surface of the end part opening of the outer ring member 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearing unit cover for closing an end opening of a bearing unit provided in a wheel unit of an automobile or a rotation mechanism of an electric / electronic device for detecting, for example, a rotational speed.

  A bearing unit equipped with a detection device for detecting the rotational speed of a wheel is incorporated in a wheel portion of an automobile in which an antilock brake is employed.

  For example, in the bearing unit shown in Patent Document 1 below, a cylindrical pulse rotor is attached to the end of the inner ring shaft, and a sensor including a coil, a yoke, and the like is provided around the pulse rotor. A rotation state is detected by a sensor to detect a rotation speed of the wheel.

  In such a bearing unit with a rotational speed detection device, a cover is provided at the end of the bearing in order to shut off the pulse rotor and sensors from the outside.

For example, in the bearing unit shown in FIG. 7, an inner ring shaft (1) as an inner ring member is rotatably mounted inside a metal cylindrical outer ring member (2) via a rolling element (3). A metal cover (4) is fitted and attached to the inner peripheral surface of the end opening (2a) in (2). A detected object such as a pulse rotor is attached to the end of the inner ring shaft (1), and sensors such as a coil and a yoke are formed of a resin body and attached to the inside of the cover (4). .
JP-A-8-194007 (FIG. 1-2)

  However, the metal cover in the conventional bearing unit described above is manufactured by subjecting a steel plate to a number of plastic workings such as drawing and bending, which results in a decrease in production efficiency and an increase in cost. However, there is a problem that the weight increases.

  On the other hand, in recent years, a technique for forming the entire bearing unit cover by a synthetic resin injection-molded product has been studied. Sensors are directly assembled in the resin cover at the time of injection molding, or screw parts for attaching the sensors are formed, and the sensors are attached to the screw parts.

  In such a resin cover, it can be efficiently produced by injection molding, the cost can be reduced, and the weight can be sufficiently expected.

  However, since the bearing unit with a rotational speed detection device is used in a severe usage environment where the temperature changes drastically, such as an undercarriage of an automobile, the resin cover of the bearing unit can sufficiently withstand the intense temperature change. For example, heat resistance that can withstand a heat cycle test of + 150 ° C. to −40 ° C. is required.

  More specifically, the bearing unit cover is required to have strength and mounting stability in a high-temperature environment in order to prevent the bearing unit cover from falling off the outer ring member. In addition to this, in order to seal a lubricant such as grease filled in the bearing, oil resistance is required, and airtightness (adhesion) at the time of fitting to the outer ring member is also required.

  As described above, since the bearing unit cover is required to have many excellent characteristics, it has been difficult to obtain a resin material that satisfies all these characteristics.

  For example, in a resin cover for a bearing unit formed using a PPS (polyphenylene sulfide) -based resin having high heat resistance, the toughness is insufficient and there is a risk that cracks and breakage may occur at an early stage. Furthermore, since the PPS resin is a relatively expensive material, there is a concern about an increase in cost.

  The present invention solves the above-mentioned problems of the prior art, has excellent properties such as heat resistance, strength, oil resistance and adhesion, and does not crack or break even under severe temperature environments, and from the outer ring member. It is an object of the present invention to provide a bearing unit cover that can reliably prevent dropping and further improve production efficiency, reduce costs, and reduce weight.

  In order to achieve the above object, the present invention provides a bearing unit comprising a cylindrical outer ring member having an open end, and an inner ring member that is rotatably assembled to the inside of the outer ring member via a rolling element. A bearing unit cover to be attached to the end opening of the outer ring member, comprising a resin cover main body made of a resin material containing 35 to 60% by weight of glass fiber containing polyamide resin as a base material. A disc-shaped closing plate portion arranged in a manner to close the end opening of the outer ring member, and an inner peripheral surface of the outer ring member that protrudes from the inner surface of the closing plate portion. The gist is provided with a cylindrical fitting portion to be fitted into the glove.

  In the bearing unit cover of the present invention, since the cover body is made of the resin material unique to the present invention, it has excellent characteristics such as heat resistance, strength and adhesion, and cracks and breakage even under harsh temperature environments In addition, when the outer ring member is mounted, it is possible to reliably prevent the dropout while sealing the end face opening.

  In addition, the cover of the present invention can be efficiently manufactured by thermoforming such as injection molding, the cost can be reduced, and the weight can be reduced as compared with a metal one.

  In the present invention, it is preferable that the fitting portion has a metal reinforcing ring that is disposed in an end opening of the outer ring member and is insert-molded in the resin cover body.

  That is, when this configuration is adopted, the heat resistance strength of the fitting portion can be improved, so that the mounting strength of the outer ring member to the end opening can be increased, and the outer ring member can be more securely dropped. Can be prevented.

  In the present invention, the resin cover body is provided with a fitting portion provided along the outer peripheral surface of the reinforcing ring and interposed between the reinforcing ring and the inner peripheral surface of the end opening of the outer ring member. It is even more preferable to employ a configuration in which a coating layer is formed.

  That is, when this configuration is adopted, the adhesion of the fitting portion to the outer ring member can be improved, the end opening can be sealed more reliably, the mounting strength can be further improved, and the outer ring member can be removed. This can be prevented more reliably. Furthermore, when the fitting part is fitted into the outer ring member, the fitting part covering layer is compressed and deformed so that it can be fitted into the outer ring member without difficulty, thereby improving the mounting workability and consequently the assembly workability of the entire bearing unit. Can be made.

  Further, the present invention preferably employs a configuration in which an outward flange-shaped flange portion embedded and fixed in the closing plate portion is formed at one end of the reinforcing ring.

  That is, when this configuration is adopted, the strength of the reinforcing ring itself is improved, and the strength of the entire cover can be further improved.

  The present invention can be suitably employed in a bearing unit with a rotational speed detection device.

  That is, in the present invention, it is desirable to employ a configuration in which the resin cover main body is provided with a rotation state detection sensor for detecting the rotation state of the detection object attached to the inner ring member.

  As described above, according to the bearing unit cover of the present invention, cracks and breakage do not occur even in a severe temperature environment, and it is possible to reliably prevent the outer ring member from falling off. There is an effect that reduction and weight reduction can be achieved.

  FIG. 1 is a cross-sectional view showing a bearing unit with a rotational speed detection device to which a cover (10) according to an embodiment of the present invention is applied. As shown in the figure, this bearing unit has a cylindrical fixed ring (2) as an outer ring member and an inner ring shaft (1) as an inner ring member coaxially through a ball (3) as a rolling element. By being incorporated, the inner ring shaft (1) is configured to be rotatable on the fixed ring (2). Furthermore, the cover (10) of this embodiment is attached to the end opening (2a) of the fixed ring (2) in the bearing unit in a closed state.

  As shown in FIGS. 1 to 3, the cover (10) is a composite having a synthetic resin cover body (11) and a metal reinforcing ring (15) insert-molded to the cover body (11). It consists of parts and is manufactured by injection molding. The cover (10) includes a disc-shaped closing plate portion (20) and a cylindrical fitting portion (13) provided in a rising manner on one surface (inner surface) of the closing plate portion (30). ing.

  The closing plate (20) is formed in a size corresponding to the end opening (2a) of the fixed ring (2), and has a mounting hole (21) for mounting sensors such as a coil and a yoke. ing.

  The fitting portion (30) has a diameter dimension corresponding to the inner diameter size of the end opening (2a) in the fixed ring (2), and fits in an fitted state on the inner peripheral surface of the end opening (2a). It is configured to be possible.

  As described above, the fitting portion (30) has a reinforcing ring (15) such as an annular sleeve that is insert-molded into the cover body (10). The reinforcing ring (15) has a cylindrical body portion (16) and an outward flange-shaped flange portion (17) bent outward from the one end edge of the body portion (16) in the diameter direction. Yes. The periphery of the flange portion (17) of the reinforcing ring (15) is fixed in an embedded state inside the peripheral edge of the closing plate portion (20), and the body portion (16) corresponds to the fitting portion (30). Be placed.

  The reinforcing ring (15) is formed by plastic working a metal plate having corrosion resistance such as a cold rolled steel plate or a stainless steel plate, or a metal plate formed with a rust prevention treatment layer such as chrome plating or electrogalvanization on the steel plate. It is composed of metal processed products.

  On the outer peripheral surface of the fitting portion (30), a fitting portion covering layer (extending along the outer peripheral surface of the trunk portion (17) of the reinforcing ring (15) from the outer peripheral edge portion on the inner surface side of the closing plate portion (20) ( 12) is integrally formed with the resin cover body (11). The end portion (tip portion) on the fitting side of the fitting portion covering layer (12) is disposed so as to protrude toward the tip side from the tip portion of the reinforcing ring (15). Further, the outer peripheral surface of the front end portion of the fitting portion covering layer (12) is formed in the tapered portion (12a) so that the fitting operation to the fixed ring (2) can be performed smoothly.

  The resin-made cover main body (11) which comprises the principal part of the cover (10) of this embodiment is comprised with the resin material (resin composition) which used the polyamide resin as the base material and contained the glass fiber.

  The polyamide resin as the base material of the resin material is excellent in strength, elongation at break, and oil resistance, and can effectively prevent the occurrence of cracks due to temperature changes and the adverse effects of the lubricant when mounted on the bearing unit. Furthermore, by adding glass fiber as a reinforcing material to this polyamide resin, it is possible to secure a linear expansion coefficient that approximates that of metal while increasing strength, and at the time of mounting to a bearing unit, it is possible to prevent elongation deformation due to temperature changes, Dropping off can be prevented.

  In this embodiment, among the polyamide resins, 66 nylon is used so that the linear expansion coefficient can be further lowered, and it can be more closely approximated to metal, so that the dropout can be more reliably performed when mounted on the bearing unit. Can be prevented.

  Note that when a resin other than polyamide resin, for example, a PPS resin, is used as the base material of the resin material, although excellent heat resistance can be ensured, sufficient toughness cannot be ensured, and cracking or breakage may occur. Absent.

  Further, the content of the glass fiber as the reinforcing material is set to 35 to 60% by weight, preferably 40 to 57% by weight, more preferably 45 to 55% by weight. That is, when the glass fiber content is too small, it is difficult to ensure sufficient strength, and the linear expansion coefficient cannot be lowered, which is not preferable. Conversely, when the glass fiber content is too high, the desired strength and linear expansion coefficient can be secured, but the viscosity of the molten resin increases and the thermoformability such as injection molding decreases. It is not preferable because the molding accuracy of details such as the coating layer (12) cannot be sufficiently secured.

  In the present embodiment, as the resin material, it is optimal to use a resin composition containing 66 wt% glass fiber in 66 nylon.

  Moreover, in this invention, when using reinforcing materials other than glass fiber, for example, carbon fiber, material cost becomes high and is not preferable. Furthermore, when a chip-shaped reinforcing material is used, the linear expansion coefficient increases, which is not preferable.

  In this embodiment, the cover (10) is manufactured by inserting and molding the annular sleep (15) using the above resin material.

  In the injection molding, it is preferable to inject a resin material at the center of the bottom surface of the closing plate portion (20) of the cover (10) as a molded product with a one-point gate. That is, the resin material used in the present embodiment has a very high glass fiber content, and the melt fluidity of the resin material is lowered, which may make it difficult to ensure the strength of the weld portion. Therefore, by injecting at one point gate, the fitting surface (fitting portion covering layer) is prevented from being welded and the strength of the portion is secured, and at the same time, the roundness of the fitting portion (30) is sufficient. To improve the assemblability.

  The cover (10) having this configuration is configured such that the fitting portion (30) is press-fitted and fixed into the end opening (2a) of the fixed ring (2) in the bearing unit, and the end opening ( 2a) is arranged so as to be closed. As shown in FIG. 1, a pulse rotor (6) as a detected body is attached to the outer periphery of the end of the inner ring shaft (1) of the bearing unit, and the closing plate portion (20) of the cover (10). Sensors (not shown) such as coils and yokes are attached to the attachment holes (21).

  As described above, in the bearing unit cover (10) in the present embodiment, the metal reinforcing ring (15) is provided on the inner peripheral side of the fitting portion (30), and the resin fitting is provided on the outer peripheral side. Since the joint covering layer (12) is provided, the covering layer (12) is supported with high strength by the reinforcing ring (15), so that the end opening inner peripheral surface of the fixed ring (2) is provided. Adheres with high pressure. For this reason, the attachment strength of the cover (10) to the bearing unit can be sufficiently secured, the cover (10) can be prevented from falling off, and the end opening (2a) can be reliably sealed.

  Moreover, since the fitting portion covering layer (12) uses a specific resin material having a polyamide resin as a base material, appropriate flexibility or adhesion can be obtained. For this reason, it is possible to improve the close contact with the inner peripheral surface of the end opening, to seal the end opening (2a) more reliably, and to fit the fitting part (30) when fitting the fixed ring (2). By the compression deformation of the joint cover layer (12), it can be fitted into the fixed ring (2) without difficulty, so that the mounting workability can be improved and the mounting strength can be further improved, and the cover (10) Can be more reliably prevented.

  Furthermore, since the fitting portion covering layer (12) has good breaking elongation characteristics, the fitting portion covering layer (12) is cracked or broken when fitted into the fixed ring (2). It is possible to reliably prevent problems such as the occurrence of defects.

  Furthermore, since the resin cover body (11) has a small coefficient of linear expansion and excellent heat resistance, it is possible to prevent harmful thermal deformation, strength reduction, etc., even by severe temperature changes. ) Can be reliably avoided.

  Here, in this embodiment, the thickness of the fitting portion covering layer (12) is preferably set to 0.3 to 1.5 mm, more preferably 0.5 to 1.0 mm. That is, if this thickness is too thin, the covering layer (12) may be cracked when the fitting portion (30) is fitted into the end opening (2a) of the fixed ring (2). On the contrary, when the thickness of the coating layer (12) is too thick, there is a possibility that the attachment strength of the cover (10) to the fixed ring (2) cannot be secured sufficiently.

  Further, the cover (10) of this embodiment is formed with an outward flange-shaped flange portion (17) in the inserted reinforcing ring (15), and the flange portion (17) is placed in the resin cover main body (11). Since the outer peripheral surface of the reinforcing ring (15) is covered with the fitting portion covering layer (12), the reinforcing ring (15) is firmly integrated with the resin cover body (11), A stable and high-quality cover product can be obtained.

  Furthermore, since the cover (10) of this embodiment is inserted with a metal reinforcing ring (15), the strength can be further increased, and defects such as thermal deformation can be more reliably prevented. Omission from 2) can be more reliably prevented.

  Moreover, the cover (10) of this embodiment can be efficiently manufactured by injection molding, can reduce cost, and can achieve weight reduction compared with a metal cover etc. FIG.

  In the above embodiment, the flange portion (17) is formed on the reinforcing ring (15). However, the present invention is not limited to this, and in the present invention, for example, as shown in FIGS. As 15), a cylindrical member having no collar portion may be used.

  In the above-described embodiment, the present invention has been described by taking as an example the case where the present invention is applied to a bearing unit with a rotational speed detection device. It can also be applied to units. In this case, as shown in FIG. 6, a mounting hole for mounting sensors can be omitted in the closing plate portion (20) of the cover (10).

  Examples relating to the present invention will be described below.

<Example 1>
As shown in Table 1 above, using a molding material containing 66 nylon as a base material and containing 50% by weight of glass fiber, a steel plate reinforcing ring (thickness 1.6 mm, trunk outer diameter 65.5 mm, A cover for a bearing unit having the same configuration as that shown in FIGS. 1 to 3 was manufactured by performing injection molding by inserting an axial length of 7 mm and a flange height of 1.6 mm.

  In addition, this cover was prepared by setting the plate thickness of the closing portion to 2.5 mm, the outer diameter of the closing portion to 73.4 mm, the axial length of the fitting portion to 8 mm, and the thickness of the fitting portion covering layer to 0.7 mm. .

  In the resin molded portion of the cover of Example 1 obtained in this way, the tensile modulus of elasticity by the test method of ISO 527-2, the tensile fracture stress by the test method of ISO 527-2, the deflection temperature under load by the test method of ISO 75-2 The coefficient of linear expansion according to the test method of DIN 53 752 was measured.

  Further, a heat cycle test was performed on the cover of Example 1. That is, after the heat treatment of heating this cover at 150 ° C. for 0.5 hour and the cooling treatment of cooling at −40 ° C. for 0.5 hour are alternately repeated for 1000 hours, cracks formed on the cover surface The state of occurrence was visually observed.

  Further, after the heat cycle test, the cover was fixed by being press-fitted into an end opening in a fixed ring of the bearing unit as shown in FIG. And the de-force value from the bearing unit of the cover was measured by the compression test method. The measurement results and observation results are also shown in Table 1 above.

<Example 2>
As shown in Table 1 above, a cover was prepared in the same manner as described above by insert molding in the same manner as described above using a molding material containing 66 nylon as a base material and containing 36% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Example 3>
As shown in Table 1 above, a cover was prepared in the same manner as described above by insert molding in the same manner as described above using a molding material containing 66 nylon as a base material and containing 58% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Example 4>
As shown in Table 1 above, a cover was produced in the same manner as described above by insert molding in the same manner as described above using a molding material containing 46 nylon as a base material and containing 45% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Example 5>
As shown in Table 1 above, a cover was prepared in the same manner as described above by insert molding in the same manner as described above using a molding material containing 46 nylon as a base material and 55% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Comparative Example 1>
As shown in Table 1 above, a cover was produced in the same manner as described above by insert molding in the same manner as described above using a molding material containing 66 nylon as a base material and containing 32% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Comparative example 2>
As shown in Table 1 above, insert molding was performed in the same manner as described above using a molding material containing 66 nylon as a base material and 63% by weight of glass fiber. However, since the viscosity of the molten resin at the time of molding becomes too high, it cannot be accurately molded, and a satisfactory molded product cannot be obtained.

<Comparative Example 3>
As shown in Table 1 above, a cover was produced in the same manner as described above by insert molding in the same manner as described above using a molding material containing PPS resin as a base material and containing 50% by weight of glass fiber. The same evaluation as above was performed on this cover.

<Comparative example 4>
As shown in Table 1 above, a molding material made of PPS resin that does not contain a reinforcing material such as glass fiber is used, and injection molding is performed without inserting a core metal such as a reinforcing ring. Was made. The same evaluation as above was performed on this cover.

<Evaluation results>
As is clear from the above evaluation results, the bearing unit covers of Examples 1 to 5 related to the present invention have mechanical properties such as tensile elastic modulus and tensile breaking stress, deflection temperature under load, linear expansion coefficient, heat Excellent results were obtained in thermal characteristics such as cycle tests. Furthermore, it can be seen that the cover of the embodiment also has a large weak force value and can reliably prevent problems such as dropout.

  On the other hand, in the bearing cover of the comparative example that departs from the gist of the present invention, the comparative example 2 has a problem in moldability, and it was difficult to obtain even a good cover product. Further, other comparative examples could not obtain satisfactory results in at least one of the mechanical characteristics, thermal characteristics, and weakness values.

  The present invention can be used as a bearing unit cover for closing an end opening of a rotational speed detecting bearing unit.

It is side surface sectional drawing which shows the bearing unit to which the cover which is embodiment of this invention was applied. It is side surface sectional drawing which shows the cover for bearing units of embodiment. It is a perspective view which shows the cover for bearing units of embodiment. It is side surface sectional drawing which shows the bearing unit to which the cover which is the 1st modification of this invention was applied. It is side surface sectional drawing which shows the cover for bearing units of a 1st modification. It is side surface sectional drawing which shows the cover for bearing units which is a 2nd modification of this invention. It is side surface sectional drawing which shows the conventional bearing unit.

Explanation of symbols

1 ... Inner ring shaft (inner ring member)
2. Fixed ring (outer ring member)
2a ... End opening 10 ... Cover 11 ... Resin cover main body 12 ... Fitting part covering layer 15 ... Reinforcement ring 20 ... Closure plate part 30 ... Fitting part

Claims (5)

A bearing attached to an end opening of the outer ring member in a bearing unit comprising a cylindrical outer ring member having an open end and an inner ring member that is rotatably assembled to the inside of the outer ring member via a rolling element. A cover for the unit,
It is composed of a resin cover body made of a molded product of a resin material containing a polyamide resin as a base material and containing 35 to 60% by weight of glass fiber,
A disc-shaped closing plate portion arranged in a mode of closing the end opening of the outer ring member;
A bearing unit cover, comprising: a cylindrical fitting portion protruding from an inner surface of the closing plate portion and fitted to an inner peripheral surface of an end opening of the outer ring member.   The bearing unit cover according to claim 1, wherein the fitting portion includes a metal reinforcing ring that is disposed in an end opening of the outer ring member and is insert-molded in the resin cover main body.   The resin cover main body is formed with a fitting portion covering layer provided along the outer peripheral surface of the reinforcing ring and interposed between the reinforcing ring and the inner peripheral surface of the end opening of the outer ring member. The bearing unit cover according to claim 2.   The bearing unit cover according to claim 2 or 3, wherein an outward flange-shaped flange portion embedded and fixed in the closing plate portion is formed at one end of the reinforcing ring.   5. The bearing unit according to claim 1, wherein the resin cover main body is provided with a rotation state detection sensor for detecting a rotation state of a detected object attached to the inner ring member. cover.

Images