JP2017203528A - Manufacturing method of bearing cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a bearing cap capable of making a cap body as a molding easily remain at a side of a fixed mold disposed at an axial outer side, in opening a molding space in a process for manufacturing the bottomed cylindrical cap body having an insertion hole axially penetrated, on a part of a resin bottom plate portion, by axial draw-molding.SOLUTION: A part adjacent to an insertion hole 17a, of a thick portion 16a disposed on a resin bottom plate portion 13a of a cap body 9a, is provided with a thinned portion 45 opened only at an axial outer face side of the thick portion 16a. A thinned portion molding portion 54 for molding the thinned portion 45, is disposed on a part of a fixed mold 51 configuring a molding device 50 used in axially draw-molding the cap body 9a. By applying this constitution, a problem can be solved.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method of manufacturing a bearing cap used to support an sensor while closing an axial end opening of an outer ring constituting a rolling bearing unit.

  Combining a rolling bearing unit for supporting a wheel for supporting a wheel of an automobile rotatably with respect to a suspension device and a rotational speed detecting device for detecting the rotational speed of a wheel necessary for control of an ABS or the like. Conventionally, a rolling bearing unit with a rotational speed detecting device has been widely used.

  FIG. 14 shows one described in Patent Document 1 as an example of a conventional structure of a rolling bearing unit with such a rotational speed detection device. This rolling bearing unit 1 with a rotational speed detection device has a hub 3 that rotates together with a wheel (not shown) when used on an inner diameter side of an outer ring 2 that does not rotate while being supported and fixed to a suspension device when used. Is rotatably supported via a plurality of rolling elements 4 and 4. A fixed-side flange 5 is provided on the outer peripheral surface of the outer ring 2 to be coupled and fixed to a knuckle (not shown) constituting the suspension device. A rotation side flange 6 for supporting and fixing the wheel is provided on the outer peripheral surface of the hub 3 near the outer end in the axial direction. In the entire specification and claims, regarding the rolling bearing unit (including the bearing cap and the rotational speed detection device), “outside” with respect to the axial direction refers to the width direction of the vehicle body when assembled in the vehicle. The side which becomes an outer side is said, and the left side of FIGS. 1, 2, 10, 14 and the lower side of FIGS. On the contrary, the right side of FIGS. 1, 2, 10, and 14 and the upper side of FIGS.

  In addition, the axial outer end opening of the space where the rolling elements 4, 4 are installed between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3 is closed by a seal ring 7. On the other hand, the axially inner end opening of the outer ring 2 is closed by a bottomed cylindrical bearing cap 8. The bearing cap 8 is made of a synthetic resin, and is composed of a cap main body 9 which is formed in a bottomed cylindrical shape as a whole, and a metal ring 10 and a nut 11 which are fixed to the cap main body 9 by molding (fixed by insert molding). Has been. Of these, the cap body 9 is provided in a state of closing the resin cylinder portion 12 and the axial inner end portion of the resin cylinder portion 12, and the outer peripheral portion thereof is coupled to the axial inner end portion of the resin cylinder portion 12. And a resin bottom plate portion 13. And the said resin cylinder part 12 is attached to the axial direction inner end part of the said outer ring | wheel 2 coaxially with this outer ring | wheel 2 (concentric). For this purpose, specifically, the metal ring 10 fixed to the front half (axially outer half) of the resin cylinder 12 is press-fitted into the outer peripheral surface of the axially inner end of the outer ring 2 ( It is fixed by external fitting. Thus, the bearing cap 8 is attached to the axially inner end portion of the outer ring 2 in a state in which the axially inner end opening of the outer ring 2 is closed.

  An annular encoder 14 constituting a rotational speed detection device is supported and fixed coaxially with the hub 3 at the axially inner end of the hub 3. On the detected surface (the inner side surface in the axial direction) of the encoder 14, S poles and N poles are alternately arranged at equal pitches in the circumferential direction. Further, a synthetic resin sensor holder 15 constituting a rotational speed detecting device is supported and fixed to the resin bottom plate portion 13 constituting the bearing cap 8. For this purpose, in the resin bottom plate portion 13, a thick portion 16 having a larger axial thickness than the other portions is provided in a portion in the circumferential direction. In addition, an insertion hole 17 penetrating in the axial direction is formed in a portion of the thick portion 16 facing a part of the detected surface of the encoder 14 in the axial direction, and adjacent to the insertion hole 17. The nut 11 is fixed to the part by molding. Then, a rod-shaped (cylindrical or quadrangular prism-shaped) holder main body portion that embeds a sensor having a magnetic detection element such as a Hall element at the tip end portion (axially outer end portion) of the sensor holder 15. 18 is inserted into the insertion hole 17. Further, a bolt 20 inserted through a mounting flange portion 19 provided at the base end portion of the holder main body portion 18 is screwed into the nut 11. Thereby, the sensor holder 15 is supported and fixed to the bearing cap 8.

  When the rolling bearing unit 1 with the rotational speed detecting device as described above is used, the fixed-side flange 5 fixed to the outer peripheral surface of the outer ring 2 is coupled and fixed to a knuckle constituting the suspension device by a bolt (not shown). At the same time, the wheel is fixed to the rotation side flange 6 fixed to the outer peripheral surface of the hub 3 by a stud bolt provided on the rotation side flange 6 so that the wheel is rotatably supported by the suspension device. When the wheel rotates in this state, the S pole and the N pole arranged on the detection surface of the encoder 14 alternately pass through the vicinity of the sensor held at the tip of the holder body 18. As a result, the density of the magnetic flux flowing in the detection part of this sensor changes, and the output signal of this sensor changes. The frequency at which the sensor output signal changes in this way is proportional to the rotational speed of the wheel. Therefore, if this output signal is sent to a controller (not shown), ABS and TCS can be appropriately controlled.

  A synthetic resin-made bottomed cylindrical cap body 9 that constitutes the bearing cap 8 having the conventional structure as described above is manufactured by axial draw molding, which is an aspect of injection molding. A mold apparatus for performing axial draw molding includes a fixed mold and a movable mold, and a space for molding the cap body 9 based on moving the movable mold in the axial direction relative to the fixed mold. (Cavity) is formed (clamping) and opened (die opening). The metal ring 10 and the nut 11 are molded and fixed to the cap body 9 simultaneously with the axial draw molding of the cap body 9. In addition, the fixed mold is usually arranged on the outer side in the axial direction with respect to the molding space of the cap body 9, has a mold shape for molding the inner diameter side surface of the cap body 9, and a mold apparatus. And an ejector pin for removing the cap body 9 as a molded product from the fixed mold. On the other hand, the movable mold is arranged on the inner side in the axial direction with respect to the molding space, has a mold shape for molding the outer diameter side surface of the cap body 9, and has a molten resin in the molding space. It has a gate to supply Throughout the specification and claims, the inside and outside of the mold apparatus in the axial direction refers to the same side as the inside and outside of the cap body that is a molded product.

  In the process of performing the axial draw molding of the cap body 9, when the molten resin supplied from the gate into the molding space is cooled and solidified to form the cap body 9, the cap body 9 is It is locked to the fixed mold by molding shrinkage of the resin. In this state, when the molding space is opened by moving the movable mold away from the fixed mold in the axial direction, the cap body 9 usually remains on the fixed mold side. The cap main body 9 remaining on the fixed mold side is removed from the fixed mold by being pushed by the ejector pin, and falls to a predetermined position such as a chute, a conveyor or a basket.

  However, when the insertion hole 17 is formed by the movable mold when the cap body 9 is axially drawn, the inner peripheral surface of the insertion hole is related to the movable mold due to resin molding shrinkage. Stop force is generated. As a result, when the molding space is opened, the cap body 9 remains on the movable mold side, or the cap body 9 falls to an unspecified position. It can be an obstacle. Such inconvenience is caused by reducing the radial thickness dimension and the axial length dimension of the resin cylinder portion 12 (the relationship between the inner peripheral surface of the resin cylinder portion 12 with respect to the fixed mold, which occurs due to resin molding shrinkage). This is likely to occur when the stopping force is small).

JP 2009-149121 A

  In view of the circumstances as described above, the present invention provides a cap body made of a synthetic resin provided with an insertion hole which is an axial through hole in a thick portion of a resin bottom plate portion that closes an axial inner end opening of a resin cylinder portion. In the process of forming by axial draw molding using a fixed mold disposed on the outside in the axial direction and a movable mold disposed on the inside in the axial direction and having a portion for molding the insertion hole. The present invention has been invented to realize a bearing cap manufacturing method in which the cap body can easily remain on the fixed mold side.

The bearing cap which is the object of the manufacturing method of the present invention is an inner end in the axial direction of an outer ring in which a hub that supports an encoder at an inner end in the axial direction is rotatably supported via a plurality of rolling elements on the inner side in the radial direction. It is used to close the axial inner end opening of the outer ring and support and fix the sensor holder in a state where it is mounted on the outer ring, and includes a cap body.
The cap body is made of a synthetic resin and has a bottomed cylindrical shape. The cap body is attached to the axially inner end of the outer ring coaxially with the outer ring, and the axially inner end opening of the resin cylinder is opened. A resin bottom plate portion that closes the wall, a thick portion in the resin bottom plate portion that is thicker in the axial direction than the surrounding portion, and a part of the encoder in the axial direction of the thick portion, An opposing hole is provided with an insertion hole for inserting a part of the sensor holder provided in a state of passing through the thick part in the axial direction.
The method for manufacturing a bearing cap according to the present invention includes a fixed mold that does not move (does not displace), the cap main body being arranged on the outer side in the axial direction with reference to the position of the molding space of the cap main body, and the fixed mold. And injection using a mold apparatus comprising a movable mold that constitutes the molding space and is arranged inward in the axial direction with respect to the position of the molding space and moves in the axial direction relative to the fixed mold. Made by molding (axial draw molding). At this time, the fixed mold causes the inner peripheral surface of the resin tube portion and a portion of the thick portion separated from the insertion hole (preferably, a portion adjacent to the insertion hole). A thinned portion provided in an open state only on the axially outer surface side of the thick portion is formed, and the insertion hole is formed by the movable mold. As a result, due to molding shrinkage of the resin generated in the molding space, not only the inner peripheral surface of the resin cylinder portion but also the inner peripheral surface of the thinned portion generates a locking force for the fixed mold.

In addition, when the bearing cap manufacturing method of the present invention is carried out, a nut for screwing a bolt used for fixing the sensor holder to the resin bottom plate portion is additionally provided. Among these, it is possible to mold-fix to a portion adjacent to the insertion hole with the thinning portion interposed therebetween. In other words, the thinned portion can be provided between the portion where the insertion hole is provided and the portion where the nut is fixed in the thick portion.
When the bearing cap manufacturing method of the present invention is carried out, the metal ring is additionally fitted and fixed to the inner end in the axial direction of the outer ring while being fixed to the resin cylinder. Can also be provided.

Further, as described above, the mold apparatus used in the manufacturing method of the present invention is used for axial draw molding of the cap body constituting the bearing cap, and includes a fixed mold and a movable mold. .
Of these, the fixed mold is arranged on the outer side in the axial direction with respect to the position of the molding space of the cap body, and does not move.
The movable mold constitutes the molding space together with the fixed mold, and is disposed on the inner side in the axial direction with reference to the position of the molding space, and moves in the axial direction relative to the fixed mold. .
The fixed mold includes a portion for forming the inner peripheral surface of the resin tube portion and the thinned portion, and the movable die includes a portion for forming the insertion hole.

  When the bearing cap manufacturing method of the present invention is carried out, additionally, as in the invention described in claim 2, a removal part forming which is a part of the fixed mold for forming the removal part. The shape of the part can be a quadrangular frustum that tapers from the outside in the axial direction toward the inside in the axial direction. In addition, with respect to the four trapezoid side surfaces constituting the outer peripheral surface of the thinned portion molding portion, the angle of intersection between a pair of trapezoid side surfaces located on opposite sides in the radial direction is 1 to 3 ° (preferably 1 5 to 2.5 °). In addition, a cooling fluid flow path formed by a circular hole extending in the axial direction and a partition plate inserted inside the circular hole is provided inside the thinned portion molding portion. Can do. Then, the cap body can be injection-molded while the cooling fluid is allowed to flow through the flow path.

A rolling bearing unit incorporating a bearing cap that is the object of the manufacturing method of the present invention is, for example, for rotatably supporting a wheel (driven wheel) of an automobile, and includes an outer ring, a hub, and a plurality of rolling bearing units. A moving body, an encoder, and a bearing cap are provided.
Of these, the outer ring has a single-row or double-row outer ring raceway on the inner peripheral surface.
The hub has a single-row or double-row inner ring raceway on the outer peripheral surface, and rotates during use.
Each rolling element is provided between the outer ring raceway and the inner ring raceway so as to be freely rollable. As each of these rolling elements, a ball or a tapered roller can be used.
The encoder is supported and fixed coaxially with the hub at the axially inner end of the hub, and has a detection surface coaxial with the hub on the axially inner surface. And the characteristic of this to-be-detected surface is changed by the equal pitch alternately with respect to the circumferential direction.
Further, the bearing cap is attached to the inner end of the outer ring in the axial direction while closing the axial inner end opening of the outer ring, and a sensor holder is supported and fixed to a part of the bearing cap.
And this bearing cap is a bearing cap used as the object of the manufacturing method of this invention.

According to the bearing cap manufacturing method of the present invention configured as described above, the molten resin supplied into the molding space is cooled and solidified in the process of producing the cap body by injection molding (axial draw molding). After the cap body is molded in the molding space, the cap body remains on the fixed mold side when the molding space is opened by moving the movable mold axially away from the fixed mold. It becomes easy.
That is, in the case of the present invention, due to molding shrinkage of the resin generated in the molding space, the locking force of the inner peripheral surface of the resin cylinder portion with respect to the fixed mold and the inner peripheral surface of the insertion hole with respect to the movable mold Locking force. And, when opening the molding space, the locking force of the inner peripheral surface of the resin cylinder portion with respect to the fixed mold acts as a force that leaves the cap body on the fixed mold side, The locking force of the inner peripheral surface of the insertion hole with respect to the movable mold acts as a force that leaves the cap body on the movable mold side. Further, in addition to these, in the case of the present invention, a locking force of the inner peripheral surface of the thinned portion with respect to the fixed mold is generated by molding shrinkage of the resin generated in the molding space. When the molding space is opened, the locking force of the inner peripheral surface of the thinned portion with respect to the fixed mold acts as a force that leaves the cap body on the fixed mold side. Therefore, in the case of the present invention, the cap body is disposed on the side of the fixed mold when the molding space is opened by the amount of the locking force of the inner peripheral surface of the thinned portion with respect to the fixed mold. It becomes easy to remain in.
Furthermore, when the present invention is carried out, if the thinning portion is provided in a portion adjacent to the insertion hole, the inner peripheral surface of the insertion hole with respect to the movable mold is released when the molding space is opened. The moment that acts on the resin bottom plate portion by the stopping force and the locking force of the inner peripheral surface of the thinning portion with respect to the fixed mold can be suppressed to be small. Therefore, it is possible to effectively prevent the cap main body, which is still soft immediately after completion, from being deformed by the moment.

Sectional drawing of the rolling bearing unit with a rotational speed detection apparatus incorporating the bearing cap of the 1st example of embodiment of this invention. Sectional drawing which similarly takes out and shows a bearing cap. The figure seen from the left side of FIG. Viewed from the right side of FIG. The figure seen from the lower part of FIG. Sectional drawing which shows the state which injection-molds a cap main body using a metal mold apparatus. The expanded AA sectional view of FIG. FIG. 8 is a cross-sectional view taken along the line BB in FIG. The perspective view which shows the partition plate with a plug used in order to comprise the flow path of the cooling fluid. The figure similar to FIG. 2 regarding the 2nd example of embodiment of this invention. The figure seen from the left side of FIG. The figure similar to FIG. 3 regarding the 3rd example of embodiment of this invention. FIG. 11 is an enlarged CC cross-sectional view of FIG. 10. Sectional drawing which shows the rolling bearing unit with a rotational speed detection apparatus incorporating the bearing cap of the conventional structure.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS.
A rolling bearing unit 1a with a rotational speed detection device incorporating a bearing cap 8a to be manufactured in this example supports a wheel as a driven wheel rotatably with respect to a suspension device such as a knuckle. A rotation speed is detected, and a hub 3a, which is a rotating ring, is rotatably supported via a plurality of rolling elements 4, 4 on the inner diameter side of an outer ring 2a, which is a stationary ring.

  The outer ring 2a has a fixed-side flange 5a for coupling and fixing to a knuckle (not shown) constituting a suspension device on the outer peripheral surface, and double-row outer ring raceways 21a and 21b on the inner peripheral surface. The hub 3a is formed by coupling and fixing a hub body 22 and an inner ring 23 by a caulking portion 24. The hub 3a has double-row inner ring raceways 25a and 25b on the outer peripheral surface, and is provided on the inner diameter side of the outer ring 2a. The outer ring 2a is supported coaxially. A rotation-side flange 6a for supporting the wheel is provided at a portion of the hub body 22 that protrudes outward in the axial direction from the axial outer end opening of the outer ring 2a. . A plurality of rolling elements 4, 4 are provided between the outer ring raceways 21a, 21b and the inner ring raceways 25a, 25b. In the example shown in the figure, balls are used as the rolling elements 4 and 4, but in the case of a rolling bearing unit for automobiles that is heavy in weight, tapered rollers may be used.

  An annular encoder 14a constituting a rotational speed detecting device is supported and fixed coaxially with the hub 3a at the inner end in the axial direction of the inner ring 23 constituting the hub 3a. The encoder 14 a includes a support ring 26 and an encoder body 27. Of these, the support ring 26 is formed into an annular shape with an L-shaped cross section by applying press processing to a ferritic stainless steel plate such as SUS430 or a rolled steel plate such as SPCC. A support ring portion 29 provided in a state of being bent radially inward from the axial inner end portion of the support cylindrical portion 28 is provided. Of these, the axially outer end portion or intermediate portion of the support cylindrical portion 28 is externally fitted and fixed to the axially inner end portion of the inner ring 23 by an interference fit. The encoder main body 27 is made of a permanent magnet such as a rubber magnet or a plastic magnet mixed with a magnetic material such as ferrite powder, and is formed on the inner surface in the axial direction of the support ring portion 29. It is fixed by attachment. On the detected surface 30 which is the inner side surface of the encoder body 27 in the axial direction, S poles and N poles are alternately arranged at equal pitches in the circumferential direction.

  Further, the outer opening in the axial direction of the space where the rolling elements 4 and 4 are installed between the inner peripheral surface of the outer ring 2 a and the outer peripheral surface of the hub 3 a is closed by a seal ring 7. On the other hand, a bottomed cylindrical bearing cap 8a is attached to the inner end of the outer ring 2a in the axial direction to close the inner end opening of the outer ring 2a in the axial direction. The bearing cap 8a is supported and fixed by a sensor unit 31 constituting a rotational speed detection device in use. The sensor unit 31 includes a sensor holder 32 and a sensor 33 made of synthetic resin. Among these, the sensor holder 32 includes a columnar (bar-shaped) holder main body 34 and a mounting flange 35 provided at the base end (the inner end in the axial direction, the right end of FIG. 1) of the holder main body 34. And. The sensor 33 is composed of an IC incorporating a magnetic sensing element such as a Hall IC, Hall element, MR element, GMR element, and a waveform shaping circuit, and the tip of the holder body 34 (the outer end in the axial direction). The mold is fixed (embedded) at the left end of FIGS.

  The bearing cap 8a is composed of a cap body 9a made of a synthetic resin and having a bottomed cylindrical shape, and a metal ring 10a and a nut 11a that are fixed to the cap body 9a by molding.

  The cap body 9a is formed into a bottomed cylindrical shape by injection molding (axial draw molding) of synthetic resin, and the resin cylinder portion 12a and the axially inner end opening of the resin cylinder portion 12a are formed. And a resin bottom plate portion 13a to be closed. In addition, as a synthetic resin which comprises this cap main body 9a, the fiber reinforced polyamide resin material which added the glass fiber suitably to the polyamide 66 resin can be used, for example. In addition, if necessary, an amorphous aromatic polyamide resin (modified polyamide 6T / 6I) and a low water-absorbing aliphatic polyamide resin (polyamide 11 resin, polyamide 12 resin, polyamide 610 resin, polyamide 612 resin) are added to the polyamide resin. Water resistance may be further improved by adding appropriately.

  In any case, out of the resin cylinder part 12a and the resin bottom plate part 13a constituting the cap body 9a, the resin cylinder part 12a has a front half part (an axially outer half part, a left half part in FIGS. 1 and 2). ) And a large-diameter cylindrical portion 37 provided in the base half (the inner half in the axial direction, the right half in FIGS. It is configured as a stepped cylinder. And the said metal ring 10a is mold-fixed to such a resin cylinder part 12a. The metal ring 10a is made of a stainless steel plate, a rolled steel plate, or the like, has an L-shaped cross section, a cylindrical portion 39, and an outward flange portion 40 that is bent radially outward from an axial inner end portion of the cylindrical portion 39. And. Of these, the cylindrical portion 39 is exposed to the outside of the large-diameter cylindrical portion 37 and is disposed adjacent to the radially outer side of the small-diameter cylindrical portion 36, whereas the outward flange portion 40 It is embedded inside the cylindrical portion 37. Further, a locking groove 41 extending over the entire circumference is formed in the inner diameter side half of the stepped surface 38, and an O-ring 42 is locked in the locking groove 41.

  The resin bottom plate portion 13a is formed in a substantially disc shape as a whole. Among such resin bottom plate portions 13a, in the used state, the width direction of the upper end portion (front-rear direction when assembled to the vehicle, front and back directions in FIGS. 1, 2, 6 and left-right direction in FIGS. In addition, a thick portion 16a having an axial thickness larger than the other portions (bulging toward both sides in the axial direction) is provided. An insertion hole 17a is provided at the upper end of the thick part 16a at a portion facing the part of the detected surface 30 of the encoder 14a in the axial direction so as to penetrate the thick part 16a in the axial direction. It has been. The insertion hole 17a is for inserting the holder main body 34 constituting the sensor holder 32 without rattling. The insertion hole 17a has an inner peripheral surface (a tapered shape provided at the inner end in the axial direction). (Excluding the guide surface portion) has an inner diameter dimension slightly larger than the outer diameter dimension of the holder main body section 34.

  The nut 11a is fixed to the lower end of the thick part 16a by molding. The nut 11a is a bottomed cylindrical cap nut having a bottom at the outer end in the axial direction. The nut 11a has a female threaded portion 43 formed on the inner peripheral surface and one or more (in the figure) axial directions on the outer peripheral surface. Engaging grooves 44 are formed in two places in the example of FIG. A part of the synthetic resin constituting the thick portion 16a is made to enter each of the engaging concave grooves 44, 44. In the case of this example, the inner surface in the axial direction of the thick portion 16a is entirely located on the same virtual plane, and the inner end surface in the axial direction of the nut 11a is also located on this virtual plane. Yes. On the other hand, in the case of this example, the axially outer side surface of the thick portion 16a has a lower end protruding slightly outward (in the axial dimension δ) from the upper end and the vertical middle. It is the exit part 63.

  In the case of this example, the shape of the thick portion 16a viewed from the axial direction is a bowl shape having a constricted portion at the middle portion (center portion) in the vertical direction. Thus, the thinned portion 45 opened only on the outer side in the axial direction of the thick portion 16a at a portion sandwiched between the insertion hole 17a and the nut 11a, which is a portion adjacent to the insertion hole 17a. Is provided. In other words, the nut 11a is molded and fixed to a portion of the thick portion 16a adjacent to the insertion hole 17a with the thinned portion 45 interposed therebetween. In the case of this example, by providing such a thinning portion 45, each portion constituting the thick portion 16a (including the insertion hole 17a and the portion between the insertion hole 17a and the nut 11a) The thickness of the surrounding portion of the nut 11a is made as thin and uniform as possible. The outer end portion in the axial direction of the thinned portion 45 is a vertical intermediate portion of the thick outer portion 16a outside the protruding portion 63, except for the lower end edge. Opened and the lower edge is open to the overhang 63. Furthermore, in the case of this example, each portion (the peripheral portion of the metal ring 10a) constituting the resin cylinder portion 12a and the portion of the resin bottom plate portion 13a that is out of the thick portion 16a. The thickness is as thin and uniform as possible. This shortens the solidification time of the resin material when the cap body 9a is axially drawn to improve line tact, and prevents deformation of the cap body 9a due to sink marks or the like. In the case of this example, the shape of the thinning portion 45 is a truncated pyramid shape that tapers from the outside in the axial direction toward the inside in the axial direction. Further, an intersection angle α (FIGS. 6 to 7) between a pair of trapezoidal sides located on the opposite sides in the radial direction with respect to the four trapezoidal sides constituting the inner peripheral surface of the thinned portion 45 is 1 to 3 ° (preferably Is 1.5 to 2.5 °.

  In the case of this example, the cap body 9a is prevented from lacking in strength due to the reduced thickness of each part constituting the cap body 9a as described above, and the cap body 9a. In order to improve the flow of the molten resin at the time of manufacturing by injection molding, a plurality of ribs 46 and 47 are provided on the outer surface in the axial direction of the resin bottom plate portion 13a. In the case of this example, each of these ribs 46, 47 includes a plurality of plate-like ribs 46, 46 extending radially from the radial center of the resin bottom plate 13a, and the radial direction of the resin bottom plate 13a. One cylindrical rib 47 is arranged at the center portion and coaxial with the resin bottom plate portion 13a. The outer end portions of the respective plate-like ribs 46, 46 in the radial direction of the resin bottom plate portion 13a are respectively connected to the inner peripheral surface of the resin cylinder portion 12a. Of the ribs 46 and 47, the plate-like ribs 46 and 46 are mainly intended to reinforce the resin bottom plate portion 13a, and the cylindrical rib 47 is used for the flow of the molten resin during injection molding. The main purpose is improvement. In the case of this example, the axially outer end surfaces of the ribs 46 and 47 are located on the same virtual plane as the upper end portion and the vertical intermediate portion of the thick portion 16a.

  In the case of this example, of the inner side surface in the axial direction of the resin bottom plate portion 13a, the portion located on the outer peripheral edge portion is more axial than the portion adjacent to the radially inner side (excluding the thick portion 16a). An annular convex portion 48 protruding inward is provided. The annular convex portion 48 constitutes the bearing cap 8a by securing the thickness of the portion adjacent to the axially inner side of the outward flange portion 40 constituting the metal ring 10a in the resin bottom plate portion 13a. A function of receiving a pressure input when the cylindrical portion 39 of the metal ring 10a is press-fitted into the inner peripheral surface of the inner end portion in the axial direction of the outer ring 2a (internally fitting with an interference fit); It is a part for exhibiting the function of improving the flow and the function of reinforcing the cap body 9a.

  In the case of this example, a portion of the inner side surface in the axial direction of the resin bottom plate portion 13a adjacent to one side (the left side in FIGS. 4 to 5) of the thick portion 16a in the width direction is substantially semi-oval. A convex portion 49 is provided. The substantially central portion of the axially inner side surface of the convex portion 49 is used as a gate position when the cap body 9a is axially drawn.

  The cap main body 9a as described above is manufactured by axial draw molding using a mold apparatus 50 as shown in FIGS. The mold apparatus 50 includes a fixed mold 51 that does not move and a movable mold 52 that moves in the axial direction relative to the fixed mold 51.

  Among these, as shown in FIGS. 6 to 7, the fixed mold 51 is formed by abutting the fixed mold 51 and the movable mold 52 in the axial direction, and is a molding space (cavity) 53 for the cap body 9a. It is arrange | positioned on the axial direction outer side (lower side of FIGS. 6-7) on the basis of this position. Such a fixed mold 51 includes an inner diameter side surface of the cap body 9a (an inner peripheral surface of the resin tube portion 12a, an outer surface in the axial direction of the resin bottom plate portion 13a, and surfaces of the ribs 46 and 47) and It has a mold shape for molding the step surface 38 (including the locking groove 41) of the resin cylinder portion 12a.

  Therefore, the fixed mold 51 includes a thinned portion forming portion 54 for forming the thinned portion 45. The shape of the thinned portion forming portion 54 is a quadrangular frustum shape that tapers from the outside in the axial direction toward the inside in the axial direction. Further, a pair of trapezoids (arranged across the central axis of the thinned portion molding portion 54) located on the opposite sides in the radial direction with respect to the four trapezoid side surfaces constituting the outer peripheral surface of the thinned portion molded portion 54 The crossing angle α between the side surfaces is 1 to 3 ° (preferably 1.5 to 2.5 °). A cooling fluid channel 55 for cooling the mold device 50 is provided inside the fixed mold 51. In particular, in the case of this example, a part of the flow path 55 is a flow path 56 for the thinned portion forming portion for cooling the thinned portion forming portion 54. The thin-walled part forming part flow path 56 is formed in the axially extending circular hole (drill hole) 57 formed at the radial center of the thinned part forming part 54, and inside the circular hole 57. It is comprised by the inserted partition plate 58. FIG. Of these, the circular hole 57 is a bottomed hole in which the inner end in the axial direction is the bottom and the outer end in the axial direction is opened to the other part of the channel 55. The partition plate 58 is a long rectangular plate, and is inserted into the circular hole 57 through the axially outer end opening of the circular hole 57. At the same time, a columnar holding member 59 fixed to the base end portion of the partition plate 58 is provided in a portion of the fixed mold 51 facing the axially outer end opening of the circular hole 57. The holding hole 60 is held in a liquid-tight manner. In this state, the partition plate 58 divides the portion of the inside of the circular hole 57 excluding the axially inner end portion into two in the radial direction. As a result, the forward path (the flow path on the right side of FIG. 7) and the return path (the flow path on the left side of FIG. 7), and the forward path and the return path, each having a semicircular cross-sectional shape, are formed inside the circular hole 57. The U-shaped channel portion 56 for forming the thinned portion has a folded portion connected at the inner end in the axial direction. When the axial draw molding of the cap body 9a is performed, the cooling fluid flowing through the flow path 55 is placed inside the flow path 56 for the thinned portion molding portion as shown by an arrow in FIG. After flowing in from the inlet and being folded at the folded portion, it flows out from the outlet of the return path. The fixed mold 51 includes an ejector pin (not shown) for removing the cap body 9a, which is a molded product, from the fixed mold 51.

  The movable mold 52 is arranged on the inner side in the axial direction (the upper side in FIGS. 6 to 7) with the position of the molding space 53 as a reference. Such a movable mold 52 has a mold shape for molding the outer diameter side surface of the cap body 9a (the outer peripheral surface of the resin cylinder portion 12a and the axially inner surface of the resin bottom plate portion 13a). A cylindrical insertion hole forming portion 61 for forming the insertion hole 17a is provided. The movable mold 52 includes a gate (not shown) for supplying molten resin into the molding space 53.

  When the cap main body 9a is axially drawn, the movable mold 52 is brought into close contact with the fixed mold 51 in the axial direction so that the fixed mold 51 and the movable mold 52 are interposed between FIGS. A molding space 53 as shown in FIG. Then, through the gate provided in the movable mold 52, molten resin {resin melted by heating polyamide 66 resin (melting point is usually about 260 ° C.) as described above] or the like is fed into the molding space 53. The cap body 9a is molded by cooling and solidifying the molten resin in the molding space 53. In addition, as the temperature of the mold device 50 (the fixed mold 51 and the movable mold 52) is lower (for example, about 20 to 30 ° C.), the cooling and solidification of the resin proceeds faster and the line tact is improved. However, in the case of this example, in order to finish the insertion hole 17a with high accuracy, the temperature of the mold device 50 is set to 80 to 90 ° C. so that the crystallinity of the resin becomes uniform. Instead, in the case of this example, as described above, the thickness of the cap body 9a is made as thin and uniform as possible so that the resin can be quickly cooled and solidified, and the line tact can be improved. The cap main body 9a which is a molded product can be effectively prevented from being deformed such as sink marks.

  In the case of this example, the nut 11a and the metal ring 10a are set in the molding space 53 before the molten resin is fed into the molding space 53. Simultaneously with the molding, the cap body 9a is fixed to the mold. As the cooling fluid flowing in the flow path 55, water can be used when the temperature of the mold device 50 is low. In this example, the temperature of the mold device 50 is used as described above. Therefore, oil is used as the cooling fluid in order to prevent the mold apparatus 50 from being damaged due to boiling of the cooling fluid.

  When the cap body 9a is taken out from the molding space 53 after the cap body 9a is molded, the molding space 53 is opened by moving the movable mold 52 away from the fixed mold 51 in the axial direction. To do. As a result, in the case of this example, the cap body 9a which is a molded product remains on the fixed mold 51 side.

That is, in the case of this example, as the cap body 9 a is molded in the molding space 53, the inner peripheral surface of the resin cylinder portion 12 a (the small diameter cylinder portion 36) and the cylindrical rib 47 The inner peripheral surface and the inner peripheral surface located radially outside of the inner surface of the locking groove 41 are formed by molding the inner peripheral surfaces of the fixed mold 51 by molding shrinkage of resin. It is locked to the outer peripheral surface of the part. On the other hand, the inner peripheral surface of the insertion hole 17a provided in the resin bottom plate portion 13a is locked to the outer peripheral surface of the insertion hole forming portion 61 provided in the movable die 52 by resin molding shrinkage. .
When opening the molding space 53, the inner peripheral surface of the resin cylinder portion 12a, the inner peripheral surface of the cylindrical rib 47, and the inner peripheral surface of the fixed mold 51, Of the inner surface of the locking groove 41, the locking force on the inner peripheral surface located on the radially outer side acts as a force that leaves the cap body 9 a on the fixed mold 51 side. On the other hand, the locking force of the inner peripheral surface of the insertion hole 17a with respect to the outer peripheral surface of the insertion hole forming portion 61 acts as a force that leaves the cap body 9a on the movable mold 52 side.
Here, in order for the cap body 9a to remain on the fixed mold 51 side, the force that leaves the cap body 9a on the fixed mold 51 side is the force that leaves the cap body 9a on the movable mold 52 side. Must be bigger than. However, it cannot be said that the force which leaves the cap main body 9a as described above on the fixed mold 51 side is sufficiently large. That is, the inner peripheral surface of the resin cylinder portion 12a (the small diameter cylinder portion 36) and the inner peripheral surface located on the radially outer side of the inner surface of the locking groove 41 have short axial dimensions, respectively. The inner peripheral surface of the cylindrical rib 47 has a short axial dimension and is provided near the radial center of the resin bottom plate portion 13a. It cannot be said that the force locked to the outer peripheral surface of the part by the resin molding shrinkage is sufficiently large.

  Therefore, in the case of this example, in order to sufficiently increase the force that leaves the cap body 9a on the fixed mold 51 side, the thinned portion 45 is formed on the fixed mold 51 on the resin bottom plate portion 13a. For this purpose, a thinned portion forming portion 54 is provided. The inner peripheral surface of the thinned portion 45 is locked to the outer peripheral surface of the thinned portion molded portion 54 by resin molding shrinkage. When the molding space 53 is opened, the locking force of the inner peripheral surface of the thinned portion 45 with respect to the outer peripheral surface of the thinned portion molded portion 54 causes the cap main body 9 a to be attached to the fixed mold 51. Acts as a force left on the side. Therefore, in the case of this example, the cap main body is opened when the molding space 53 is opened as much as the locking force of the inner peripheral surface of the thickness reduction portion 45 with respect to the thickness reduction portion molding portion 54 is generated. 9a tends to remain on the fixed mold 51 side.

  In particular, in the case of this example, the channel 56 for the thinned portion forming portion exists in the central portion in the radial direction of the thinned portion forming portion 54. And while the cross-sectional shape of the outer peripheral surface of the said thinning part shaping | molding part 54 is a square, the cross-sectional shape of the internal peripheral surface of the said circular hole 57 which comprises the said flow path 56 for thinning part forming parts is It is circular. For this reason, based on the difference in thickness of the thinned portion molding portion 54, the outer peripheral surface of the thinned portion molded portion 54 is a central portion in the circumferential direction (width direction) of the four trapezoid side surfaces constituting the outer peripheral surface. However, the cooling performance in the vicinity of the four ridges (corners) in the circumferential direction, which is present in the continuous portion between the trapezoidal side surfaces adjacent in the circumferential direction, is poor. Therefore, at the time of molding the cap body 9a, the molten resin present around the thinned portion molding portion 54 starts to solidify from the portion that contacts the circumferential central portion of each trapezoidal side surface and contacts the vicinity of each ridge portion. The part solidifies last. As a result, in the cap body 9a, the resin in the vicinity of each ridge portion, the thick and highly rigid resin is in close contact with each other in the vicinity of each ridge portion, The locking force of the inner peripheral surface of the thinned portion 45 with respect to the outer peripheral surface of the thinned portion forming portion 54 is increased. Accordingly, when the molding space 53 is opened, the cap body 9a is likely to remain on the fixed mold 51 side. The thinned portion molding portion 54 has a small heat capacity and is covered with a molten resin, so that the temperature is likely to rise. In this regard, in the case of this example, the temperature increase of the thinned portion molding portion 54 can be suppressed by providing the thinned portion molded portion flow path 56 inside the thinned portion molded portion 54. Further, it is possible to prevent inconvenience that the solidification of the molten resin existing around the thinned portion molding portion 54 is delayed and adversely affects the line tact.

Furthermore, in the case of this example, the force (locking force) that leaves the cap body 9a on the fixed mold 51 side is greater than the force (locking force) that leaves the cap body 9a on the movable mold 52 side. However, in order to make it even larger, the following configuration is adopted.
In addition to improving the roughness of the outer peripheral surface of the insertion hole forming portion 61 as much as possible, of the outer peripheral surface of the insertion hole forming portion 61, the inner end portion in the axial direction (the inner end portion in the axial direction of the insertion hole 17a is tapered). By providing a draft angle (inclination angle with respect to the central axis of the insertion hole forming portion 61) at an angle of 10 minutes or more (for example, about 10 minutes to 10 °) in portions other than the portion that forms the guide surface portion, The locking force of the inner peripheral surface of the insertion hole 17a with respect to the outer peripheral surface of the insertion hole forming portion 61 is reduced. When the present invention is carried out, the draft of the outer peripheral surface of the insertion hole forming portion 61 (inclination angle of the inner peripheral surface of the insertion hole 17a with respect to its own central axis) is set over the entire length in the axial direction. It can also be a certain size.
Further, the roughness of the outer peripheral surface of the thinned portion molding portion 54 is made larger than the roughness of the outer peripheral surface of the insertion hole forming portion 61 so that the thickness of the thinned portion 45 with respect to the outer peripheral surface of the thinned portion molded portion 54 is increased. The locking force of the inner peripheral surface (the biting force caused by the resin entering the valley of the roughness) is increased. However, this locking force is set so as not to damage the inner peripheral surface of the thinned portion 45 when the cap body 9a is removed from the fixed mold 51 by the ejector pin.

  In addition, with respect to the four trapezoid side surfaces constituting the outer peripheral surface of the thinned portion molding portion 54, an intersection angle α between a pair of trapezoid side surfaces located on opposite sides in the radial direction is set to 0 ° (the thinned portion molded portion). 54 becomes a quadrangular prism), the biting of the resin becomes too strong with respect to the vicinity of each ridge portion of the outer peripheral surface of the thinned portion molding portion 54, and the cap body 9a is removed from the fixed mold 51 by the ejector pin. When removing, the internal peripheral surface of the said thinning part 45 may be damaged. On the other hand, if the intersecting angle α is too large, the resin bite is weak against the vicinity of each ridge on the outer peripheral surface of the thinned portion molding portion 54, and the force that leaves the cap body 9a on the fixed mold 51 side. (Locking force) cannot be secured sufficiently. Therefore, in the case of this example, in order to avoid the occurrence of these disadvantages, the intersection angle α is set to 1 to 3 ° (preferably 1.5 to 2.5 °).

  In the case of this example, the thinning portion 45 exists in a portion of the resin bottom plate portion 13a adjacent to the insertion hole 17a. For this reason, when the molding space 53 is opened, the locking force of the inner peripheral surface of the insertion hole 17a with respect to the outer peripheral surface of the insertion hole forming portion 61 and the outer peripheral surface of the thinned portion forming portion 54 are The moment acting on the resin bottom plate portion 13a due to the locking force of the inner peripheral surface of the thinned portion 45 can be kept small. Therefore, it is possible to effectively prevent the cap body 9a, which is still soft immediately after completion, from being deformed by the moment.

  As described above, in the case of this example, when the molding space 53 is opened after the cap body 9a is molded, the bearing cap 8a including the cap body 9a is moved to the fixed mold 51 side. Remain in. Therefore, the bearing cap 8a remaining on the fixed mold 51 side is removed from the fixed mold 51 by pushing it with the ejector pin, and dropped to a specified position such as a chute, a conveyor or a basket. As described above, in the case of this example, the lower end portion of the thick portion 16a in the axial direction is the upper end portion and the vertical intermediate portion (and the flat rib 46 and the cylindrical rib 47). The projecting portion 63 projects outward (in the axial direction dimension δ) slightly in the axial direction. Therefore, when the bearing cap 8a is removed from the fixed mold 51 with the ejector pin as described above, the peripheral portion of the overhanging portion 63 is also removed after the flat plate rib 46 and the cylindrical rib 47 are removed from the fixed mold 51. It is possible to make a state where the portion located in the range of the axial dimension δ is not completely detached from the fixed mold 51 (the peripheral portion of the overhang portion 63 is the axial dimension with respect to the fixed mold 51). having a margin in the range of δ). Accordingly, the bearing cap 8a pushed out from the fixed mold 51 is free to fall directly under the action of gravity without being ejected from the fixed mold 51 by the ejector pin, so that the drop position becomes more accurate. In addition, since a gap based on molding shrinkage occurs between the peripheral portion of the overhang portion 63 and the fixed die 51, the peripheral portion of the overhang portion 63 easily comes out of the fixed die 51. It is possible to prevent the fall of the bearing cap 8a as described above.

  The bearing cap 8a of the present example having the above-described configuration is configured such that the cylindrical portion 39 constituting the metal ring 10a is fitted and fixed to the inner end portion in the axial direction of the outer ring 2a with an inner fit. The outer ring 2a is attached to the inner end portion in the axial direction while closing the inner end opening in the axial direction. Further, in this state, the stepped surface 38 is abutted against the inner end surface in the axial direction of the outer ring 2a, thereby positioning the bearing cap 8a with respect to the outer ring 2a in the axial direction. At the same time, the O-ring 42 is elastically compressed between the axial inner end surface of the outer ring 2a and the bottom surface of the locking groove 41, so that the portion between both surfaces is sealed.

  In the case of this example, the sensor holder 32 is supported and fixed to the bearing cap 8a as follows. That is, the rod-shaped holder main body 34 constituting the sensor holder 32 is inserted into the insertion hole 17a without rattling. And the axial direction outer side surface of the attachment flange part 35 provided in the part near the base end of the said holder main-body part 34 is made to contact | abut to the axial direction inner side surface of the said thick part 16a. Further, in this state, a bolt (not shown) is inserted into the through hole 62 provided in the mounting flange portion 35, and the male screw portion provided at the tip of the bolt is screwed into the female screw portion 43 of the nut 11a. Tighten further. As a result, the sensor 33 embedded in the tip end portion of the holder main body 34 is made to face and oppose the detected surface 30 of the encoder 14a in the axial direction. In addition, a locking groove extending over the entire circumference is formed on the outer peripheral surface of the holder body 34, and an O-ring is locked in the locking groove, and the holder body 34 is inserted into the insertion hole 17a. The O-ring can be compressed over the entire circumference between the inner peripheral surface of the insertion hole 17a and the bottom surface of the locking groove.

  In the case of the rolling bearing unit 1a with the rotational speed detection device of the present example having the above-described configuration, the driven wheel is supported rotatably with respect to the suspension device as in the case of the conventional structure described above. It is possible to detect the rotational speed of this wheel. For this reason, ABS and TCS can be controlled appropriately.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS.
In the case of this example, of the resin bottom plate portion 13b of the cap body 9b constituting the bearing cap 8b, the axially outer side surface of the thick portion 16b is not only the lower end portion but also the axial outer end portion of the thinned portion 45a. The vertical middle portion to be opened is also an overhang portion 63a that projects slightly outward (in the axial dimension δ) from the upper end portion in the axial direction. In the case of this example, the dimension in the axial direction of the thinned portion 45a is equal to the amount of projection (axial dimension δ) of the projecting portion 63a than in the case of the first example of the embodiment described above. Is also getting bigger. Accordingly, when the cap body 9b is made by axial draw molding, the locking force of the inner peripheral surface of the thinned portion 45a with respect to the outer peripheral surface of the thinned portion molded portion 54 (see FIGS. 6 to 7) is large. Thus, when the molding space 53 is opened, the cap body 9b is more likely to remain on the fixed mold 51 side.
Other configurations and operations are the same as those in the first example of the embodiment described above.

[Third example of embodiment]
A third example of the embodiment of the present invention will be described with reference to FIGS.
In the case of this example, a cylindrical rib 47 provided on the outer surface in the axial direction of the resin bottom plate portion 13c of the cap body 9c constituting the bearing cap 8c mainly for the purpose of improving the flow of molten resin at the time of injection molding, Separately, the second cylindrical rib 64 mainly intended to improve the force that leaves the cap body 9c after injection molding on the fixed mold side is formed on the radially outer side of the cylindrical rib 47 (of the resin bottom plate portion 13c). A portion of the outer surface in the axial direction near the radially outer end is provided so as to be coaxial (concentric) with the cylindrical rib 47. Of the inner and outer peripheral surfaces of the second cylindrical rib 64, at least the inner peripheral surface is a cylindrical surface whose diameter does not change in the axial direction. Thus, at the time of injection molding, the inner peripheral surface of the second cylindrical rib 64 is strongly locked to a part of the outer peripheral surface of the fixed mold by resin molding shrinkage. In the illustrated example (as shown in FIG. 13), the outer peripheral surface of the second cylindrical rib 64 is inclined in such a direction that the diameter decreases toward the outer side in the axial direction (left side in FIG. 13). It has a tapered surface. However, when carrying out the present invention, this outer peripheral surface can also be a cylindrical surface whose diameter does not change in the axial direction. In the case of this example, flat ribs 46 and 46 are partially connected to a plurality of locations in the circumferential direction of the second cylindrical rib 64. For this reason, the molding shrinkage force of the second cylindrical rib 64 is improved by the molding shrinkage force of these flat ribs 46, 46, and the inner peripheral surface of the second cylindrical rib 64 is one of the fixed molds. The force locked to the outer peripheral surface of the part can be increased. In the illustrated example, only one second cylindrical rib 64 is provided. However, when the present invention is implemented, such second cylindrical ribs 64 have different diameters. It is also possible to provide more than one.
Other configurations and operations are the same as those in the first and second examples of the embodiment described above.

In the above-described embodiment, the bearing cap has been described by taking as an example a structure in which a synthetic resin cap body, a metal ring, and a nut are combined, but the bearing cap manufactured by the manufacturing method of the present invention, Either or both of these metal rings and nuts may not be provided.
In the embodiment described above, the bearing cap manufactured by the manufacturing method of the present invention has been described when incorporated in a rolling bearing unit for supporting a wheel. However, the bearing cap manufactured by the manufacturing method of the present invention is described. The rolling bearing unit to be incorporated is not limited to such a use, and can be applied to various uses such as a machine tool.

DESCRIPTION OF SYMBOLS 1, 1a Rolling bearing unit 2, 2a Outer ring 3, 3a Hub 4 Rolling element 5, 5a Fixed side flange 6, 6a Rotation side flange 7 Seal ring 8, 8a-8c Bearing cap 9, 9a-9c Cap main body 10, 10a Metal Ring 11, 11a Nut 12, 12a Resin tube part 13, 13a-13c Resin bottom plate part 14, 14a Encoder 15 Sensor holder 16, 16a Thick part 17, 17a Insert hole 18 Holder body part 19 Mounting flange part 20 Bolt 21a, 21b Outer ring raceway 22 Hub body 23 Inner ring 24 Caulking portion 25a, 25b Inner ring raceway 26 Support ring 27 Encoder body 28 Support cylindrical part 29 Support ring part 30 Detected surface 31 Sensor unit 32 Sensor holder 33 Sensor 34 Holder body part 35 Mounting flange part 36 Small diameter cylinder part 37 Large diameter cylinder part 38 Stepped surface 39 Cylindrical part 40 Outward flange part 41 Locking groove 42 O-ring 43 Female thread part 44 Engaging concave groove 45 Thinning part 46 Flat rib 47 Cylindrical rib 48 Annular convex part 49 Convex part 50 Mold device 51 Fixed mold 52 Movable mold 53 Molding space 54 Thinning part molding part 55 Flow path 56 Thinning part molding part flow path 57 Circular hole 58 Partition plate 59 Holding member 60 Holding hole 61 Insertion hole molding part 62 Through hole 63, 63a Overhang 64 Second cylindrical rib

Claims (2)

With the hub that supports the encoder at the inner end in the axial direction mounted on the inner end in the axial direction of the outer ring that is rotatably supported via a plurality of rolling elements on the inner side in the radial direction, the axial direction of the outer ring Used to close the inner end opening and support and fix the sensor holder,
A resin cylinder part made of a synthetic resin in a bottomed cylindrical shape and attached coaxially to the outer ring at the axially inner end part of the outer ring, and a resin bottom plate part closing the axially inner end opening of the resin cylinder part, A thickness portion of the resin bottom plate portion that is thicker in the axial direction than the surrounding portion, and a portion of the thick portion facing the part of the encoder with respect to the axial direction. Provided with a cap body having an insertion hole for inserting a part of the sensor holder provided in a state of penetrating the meat part in the axial direction;
A method for manufacturing a bearing cap, comprising:
The cap body is arranged on the outer side in the axial direction with respect to the position of the molding space of the cap body, and the stationary space is configured together with the stationary mold that does not move, and the position of the molding space is determined. It is made by injection molding using a mold device that is arranged on the inner side in the axial direction as a reference and that is movable with respect to the fixed mold in the axial direction. At this time, the resin cylinder is And forming a thinned portion provided in a state of opening only on the outer side in the axial direction of the thick portion at a portion separated from the insertion hole in the thick portion. The fixed hole is formed not only on the inner peripheral surface of the resin tube portion but also on the inner peripheral surface of the thinned portion by molding the insertion hole with the movable die and molding shrinkage of the resin generated in the molding space. It is characterized by generating a locking force against Manufacturing method of bearing cap. Of the fixed mold, the shape of the thinned portion forming portion that is a portion for forming the thinned portion is a truncated pyramid shape that tapers from the axially outer side toward the axially inner side,
With respect to the four trapezoid side surfaces constituting the outer peripheral surface of the thinned portion molding portion, the angle of intersection between a pair of trapezoid side surfaces located on opposite sides in the radial direction is 1 to 3 °,
While flowing the cooling fluid through the cooling fluid flow path, which is provided in the inside of the thinned portion molding portion and includes a circular hole extending in the axial direction and a partition plate inserted inside the circular hole, The method for manufacturing a bearing cap according to claim 1, wherein injection molding of the cap body is performed.

Images