Hub unit bearing with sensor

Abstract

In a sensor-equipped cap that is fitted and fixed to the inboard end of an outer member, the resin thickness of the cylindrical portion into which the core metal is insert-molded is increased to mitigate the effects of changes in the tightening allowance of the cylindrical portion and maintain good watertight performance. [Solution] The sensor holder cap 30 of the sensor-equipped hub unit bearing 1 has a metal annular core 40, a cylindrical part 51 made of synthetic resin which is integrally formed on the outer diameter side of the core 40 and fitted and fixed to the inner circumferential surface of the inboard end of the outer member 2, and a sensor housing part 54. The core 40 extends from the portion located on the inner diameter side of the inboard end of the outer member 2 toward the inboard side. The core 40 has a small diameter portion 44a in the portion located on the inner diameter side of the inboard end of the outer member 2 whose outer diameter is smaller than the outer diameter of the cylindrical part extending toward the inboard side. The inner circumferential surface of the core 40 has a uniform inner diameter over the entire width of the core 40 or an inner diameter which is widened toward the inboard side.

Description

Technical Field

[0001] The present invention relates to a hub unit bearing with a sensor that rotatably supports a wheel with respect to a suspension device and incorporates a rotational speed sensor for detecting the rotational speed of the wheel.

Background Art

[0002] Conventionally, in a suspension device such as an automobile, a hub unit bearing that rotatably supports a wheel is known. In the hub unit bearing, there is a type to which a rotational speed sensor for detecting the rotational speed of the wheel is added in order to control an antilock brake system (ABS).

[0003] For example, in the wheel bearing device 100 with a rotational speed detection device described in Patent Document 1, as shown in FIG. 9, a plurality of rolling elements 103 are arranged to be freely rotatable between a double-row outer ring raceway 101a formed on the inner peripheral surface of an outer member 101 and a double-row inner ring raceway 102a formed on the outer peripheral surface of an inner member 102. And, on the inboard side end of the outer member 101, a resin cap body 105 to which a rotational speed sensor 109 is attached is fitted and fixed, and the rotational speed sensor 109 detects the change in magnetic poles of a magnetic encoder 104 fixed to the inner member 102.

[0004] The cap body 105 has a cylindrical portion 107 in which a core metal 106 is insert-molded on the inner diameter side, and a bottom plate portion 108 that is continuous from the cylindrical portion 107 and closes the opening 101b on the inboard side of the outer member 101. An insertion hole 110 for mounting the rotational speed sensor 109 is provided in the bottom plate portion 108. Then, by press-fitting the resin cylindrical portion 107 into the inner peripheral surface 101c formed at the inboard side end of the outer member 101, the space between the inner peripheral surface 101c and the cylindrical portion 107 is sealed watertightly to close the opening 101b on the inboard side of the outer member 101.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] A certain degree of thickness in the resin cylindrical portion 107 is preferable because it can mitigate the effects of variations in the clamping force with the inner circumferential surface 101c of the inboard end of the outer member 101, which are caused by variations in the outer diameter of the cylindrical portion 107. However, the outer diameter of the cylindrical portion 107 is limited by the inner circumferential surface 101c of the inboard end of the outer member 101, and furthermore, the inner diameter of the cylindrical portion 107 is limited by the rotational speed sensor 109 positioned opposite the magnetic encoder 104, together with the core metal 106 provided on the inner diameter side of the cylindrical portion 107.

[0007] A larger outer diameter is advantageous for the magnetic encoder 104 in order to improve magnetic flux density, improve the accuracy of the magnetic signal, and increase the number of poles. However, as the magnetic encoder 104 increases in size, the installation position of the rotational speed sensor 109 also moves radially outward. As described above, the outer and inner diameters of the cylindrical portion 107 are limited by the outer member 101 and the rotational speed sensor 109. Therefore, when the installation position of the rotational speed sensor 109 moves outward, it becomes difficult to secure a thickness in the cylindrical portion 107 that can mitigate the effects of changes in the interference fit, making it difficult to maintain good watertight performance.

[0008] The present invention has been made in view of the aforementioned problems, and its objective is to provide a sensor-equipped hub unit bearing in which, in a cap with a sensor holder that is fitted and fixed to the inboard end of an outer member, the resin thickness of the cylindrical portion in which the core metal is insert-molded is increased, thereby mitigating the effects of changes in the tightening allowance of the cylindrical portion and maintaining good watertight performance. [Means for solving the problem]

[0009] Therefore, the above objective of the present invention is achieved by the following configuration [1] relating to a hub unit bearing with a sensor. [1] An outer member having a double row of outer ring raceways on its inner circumferential surface, An inner member having a wheel mounting flange on the outboard side and having a double row of inner ring raceways on its outer circumferential surface that are opposite to the double row of outer ring raceways, A plurality of rolling elements are arranged to roll freely between the double-row outer ring raceway and the double-row inner ring raceway, A magnetic encoder fixed to the inboard-side end of the inner member, A cap with a sensor holder is fitted and fixed to the inner circumferential surface of the inboard-side end of the outer member, which closes the inboard-side opening of the outer member and holds a sensor for detecting changes in the magnetic poles of the magnetic encoder. A sensor-equipped hub unit bearing comprising, The sensor holder cap comprises a metal annular core, a cylindrical portion made of synthetic resin integrally formed on the outer diameter side of the core and fitted and fixed to the inner circumferential surface of the inboard end of the outer member, and a sensor housing portion capable of housing the sensor so that the sensor faces the magnetic encoder. The core metal extends inwards from the portion located on the inner diameter side of the inboard end of the outer member, The core metal has a small-diameter portion located on the inner diameter side of the inboard end of the outer member, the portion whose outer diameter is smaller than the outer diameter of the cylindrical portion extending toward the inboard side. The inner circumferential surface of the core metal has a uniform inner diameter over the entire width of the core metal, or an inner diameter that is widened on the inboard side. Hub unit bearing with sensor. [Effects of the Invention]

[0010] According to the sensor-equipped hub unit bearing of the present invention, by increasing the thickness of the resin in the cylindrical portion into which the core metal is insert-molded, the effects of changes in the interference fit of the cylindrical portion can be mitigated, thereby maintaining good watertight performance. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a cross-sectional view of a sensor-equipped hub unit bearing according to a first embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view of a cylindrical portion in which a core metal of the cap with a sensor holder shown in Figure 1 is insert-molded. [Figure 3] Figure 3(a) is a cross-sectional view of a core metal with a reduced outer diameter on the outboard side portion, and Figure 3(b) is a cross-sectional view of a core metal with an inner peripheral surface of the outboard side portion machined into a cylindrical shape. [Figure 4] Figure 4 is an explanatory diagram showing a method of machining the inner peripheral surface of a core metal with a reduced outer diameter on the outboard side portion into a cylindrical shape. [Figure 5] Figure 5(a) is a cross-sectional view of a cylindrical portion of a cap with a sensor holder according to a second embodiment of the present invention, Figure 5(b) is a cross-sectional view of a core metal in which a part of the outboard side portion is reduced in diameter to an arcuate cross-section by plastic working, and Figure 5(c) is a cross-sectional view of a core metal with an inner peripheral surface of the outboard side portion machined into a cylindrical shape. [Figure 6] Figure 6(a) is a cross-sectional view of a cylindrical portion of a cap with a sensor holder according to a first modification of the second embodiment, Figure 6(b) is a cross-sectional view of a core metal in which a part of the outboard side portion is reduced in diameter by plastic working, and Figure 6(c) is a cross-sectional view of a core metal with an inner peripheral surface of the outboard side portion machined into a cylindrical shape. [Figure 7] Figure 7 is a cross-sectional view of a cylindrical portion of a cap with a sensor holder according to a second modification of the second embodiment. [Figure 8] Figure 8 is a cross-sectional view corresponding to Figure 2 according to a modification of the cap with a sensor holder. [Figure 9] Figure 9 is a cross-sectional view of a main part of a conventional hub unit bearing with a sensor.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, each embodiment of the hub unit bearing with a sensor according to the present invention will be described in detail based on the drawings.

[0013] [First Embodiment] A hub unit bearing with a sensor according to a first embodiment of the present invention (hereinafter, also simply referred to as a hub unit bearing) will be described in detail with reference to Figures 1 and 2. Regarding the hub unit bearing, throughout this specification and the claims, the "inboard side" refers to the vehicle body side of the hub unit bearing when attached to the vehicle body, which is the right side in FIG. 1 and is also referred to as the inner side. The "outboard side" refers to the wheel side of the hub unit bearing when attached to the vehicle body, which is the left side in FIG. 1 and is also referred to as the outer side.

[0014] As shown in FIG. 1, the hub unit bearing 1 with a sensor according to this embodiment is a hub unit bearing for a driven wheel, and mainly includes an outer ring 2 as an outer member, a hub 3 as an inner member, a plurality of rolling elements 4, 4, a magnetic encoder 14, and a cap 30 with a sensor holder (hereinafter, also simply referred to as a cap).

[0015] The outer ring 2 has a stationary side flange 7 on its outer peripheral surface and double-row (two-row) outer ring raceways 8a, 8b on its inner peripheral surface. During use, the outer ring 2 is coupled and fixed to the knuckle of the suspension device by the stationary side flange 7, and rotates while being supported by this suspension device.

[0016] The hub 3 is composed of a hub shaft 9 and an inner ring 10 that is fitted and caulked to the hub shaft 9, and is arranged coaxially (concentrically) with the outer ring 2 on the radially inner side of the outer ring 2.

[0017] On the hub shaft 9, at a portion that protrudes axially outward from the axially outer side (outboard side) opening of the outer ring 2, a circular wheel mounting flange 11 that extends radially outward is provided for supporting and fixing a braking rotating member such as a wheel (driven wheel) and a disk rotor. Specifically, the wheel mounting flange 11 is provided with a plurality of insertion holes 11a, and hub bolts 17 are serration-fitted into each insertion hole 11a. Incidentally, by using the plurality of insertion holes 11a of the wheel mounting flange 11 as female screw holes and screwing in the hub bolts, it is also possible to support and fix a braking rotating member such as a wheel and a disk rotor.

[0018] Furthermore, the outer surface of the hub shaft 9 is provided with an inner ring raceway 12a for the outboard side row (one of the rows) in the portion facing the outer ring raceway 8a of the axially outer (outboard side) row of the outer ring 2. Additionally, the axially inner end of the outer surface of the hub shaft 9, facing the outer ring raceway 8b of the axially inner (inboard side) row of the outer ring 2, is provided with a small-diameter stepped portion 13. The hub shaft 9 also has a crimping portion 24 that deforms the inboard side end, which extends from the outer surface of the small-diameter stepped portion 13 toward the inboard side, radially outward to crimp and fix the inner ring 10.

[0019] The inner ring 10 is provided with an inner ring raceway 12b for the inboard side row (the other row) on its outer circumferential surface. The inner ring 10 is fitted onto the small-diameter stepped portion 13 of the hub shaft 9 with its outboard side end face abutting against the stepped surface of the small-diameter stepped portion 13, and is crimped and fixed to the hub shaft 9 by a crimping portion 24 which is deformed radially outward at the inboard side end of the small-diameter stepped portion 13.

[0020] The rolling elements 4, 4 are provided to roll freely in the space between the outer ring raceway 8a and the inner ring raceway 12a of the outboard side row, and between the outer ring raceway 8b and the inner ring raceway 12b of the inboard side row, while being held by a pair of retainers 6, 6.

[0021] A seal ring 5 is supported and fixed to the outboard end of the inner circumferential surface of the outer ring 2. The seal ring 5 closes the axial outer end opening of the internal space 18, which is located between the inner circumferential surface of the outer ring 2 and the outer circumferential surface of the hub shaft 9 and contains a plurality of rolling elements 4, 4. The seal ring 5 slides against the large-diameter stepped portion 20 on the outboard side of the outer circumferential surface of the hub shaft 9, which is on the outboard side of the inner ring raceway 12a.

[0022] An annular magnetic encoder 14 is supported and fixed to the outer circumferential surface of the inboard end of the inner ring 10. The magnetic encoder 14 consists of a support ring 26 and an encoder body 27. The support ring 26 is formed in an L-shape in cross-section and an annular shape overall by press-forming a magnetic metal plate, such as a ferritic stainless steel plate like SUS430 or a rolled steel plate like SPCC. The outboard portion of the support ring 26 is externally fitted and fixed to the inner ring 10.

[0023] The encoder body 27 is made entirely of a ring-shaped permanent magnet formed by mixing a magnetic material such as ferrite powder into rubber or thermoplastic resin, and is attached and fixed to the inboard side surface of the ring portion of the support ring 26, which is bent radially inward. The inboard side surface (detected surface) of the encoder body 27 is magnetized with alternating south poles and north poles at equal pitches in the circumferential direction.

[0024] A bottomed cylindrical cap 30 is fitted and fixed to the inner circumferential surface 2a of the inboard end of the outer ring 2, closing the opening on the inboard side of the outer ring 2.

[0025] The cap 30 comprises a metal annular core 40 and a cap body 50 made of synthetic resin. The cap body 50 is formed entirely into a bottomed cylindrical shape by injection molding (axial draw molding) of synthetic resin, and includes a cylindrical portion 51 into which the core 40 is insert-molded, and a side wall 53 that extends inward from the inboard end face of the cylindrical portion 51 and closes the inboard opening of the cylindrical portion 51.

[0026] Referring also to Figure 2, the core metal 40 is made of metal such as stainless steel sheet or rolled steel sheet, has an L-shaped cross-section, and is formed in an annular shape overall. The core metal 40 comprises an annular main body portion 41 that extends inward from the portion located on the inner diameter side of the inboard end of the outer ring 2, and a flange portion 42 formed so that the inboard end of the main body portion 41 is bent radially outward. The main body portion 41 has a tapered portion 44a in the portion located on the inner diameter side of the inboard end of the outer ring 2, which gradually decreases in diameter towards the outboard side. That is, the tapered portion 44a provided in the outboard portion 43 located on the inner diameter side of the inboard end of the outer ring 2 constitutes a small-diameter portion whose outer diameter is smaller than the outer diameter of the cylindrical portion extending inward, and as a result the thickness t1 of the outboard end portion 43a is thinner than that of the main body portion 41. Furthermore, the inner circumferential surface of the tapered portion 44a is processed by a shaving process, as described later, to have a uniform inner diameter throughout its entire width.

[0027] The synthetic resin material that makes up the cap body 50 is, for example, a fiber-reinforced polyamide resin material which is made by compounding polyamide 66 resin with glass fiber, carbon fiber, or metal fiber as a fibrous reinforcing material. Furthermore, if necessary, the water resistance may be further improved by appropriately adding amorphous aromatic polyamide resin (modified polyamide 6T / 6I) or low water-absorbing aliphatic polyamide resin (polyamide 11 resin, polyamide 12 resin, polyamide 610 resin, polyamide 612 resin) to the polyamide resin.

[0028] The cylindrical portion 51 of the cap body 50 is formed to cover the entire outer diameter side of the main body portion 41 of the core metal 41, the inboard side of the inner diameter side of the main body portion 41, and the entire flange portion 42.

[0029] The cylindrical portion 51 has a small-diameter cylindrical portion 51a that is press-fitted into the inner circumferential surface 2a of the inboard end of the outer ring 2, and its outer circumferential surface is formed in a stepped shape. Therefore, the small-diameter cylindrical portion 51a is located on the outer diameter side of the tapered portion 44a of the core metal 40.

[0030] The side wall 53 is generally constructed in a circular disc shape. A sensor housing portion 54 and a nut holding portion 57 are formed on the inboard-side end face 53a of the side wall 53, protruding toward the inboard side. The sensor housing portion 54 and the nut holding portion 57 are integrated and formed in a generally oval shape when viewed from the side.

[0031] The sensor housing section 54 is provided with a substantially cylindrical housing hole 55 that penetrates axially, facing the encoder body 27 of the magnetic encoder 14, and capable of housing the sensor 70. The inner diameter of the housing hole 55 is slightly larger than the outer diameter of the sensor 70. This prevents warping of the sensor housing section 54 or deformation of the cap 30 from affecting the mounting position of the sensor 70, and thus prevents the reading performance of the magnetic encoder 14 by the sensor 70 from being affected.

[0032] An insert nut 60 is molded and fixed to the nut holding portion 57. The insert nut 60 has an internal thread 61 formed on its inner circumferential surface.

[0033] The sensor 70 comprises a sensor body 71 and a sensor flange 72 fixed substantially perpendicular to the sensor body 71. The sensor 70 is assembled to the sensor housing 54 by inserting the sensor body 71 into the housing hole 55 and screwing a bolt 75, which is inserted through a bolt hole 73 provided at one end of the sensor flange 72, into the female thread 61 of the insert nut 60.

[0034] Next, an example of a method for forming the core metal 40 will be described. As shown in Figure 3(a), the core metal 40 is formed by bending the inboard end of the annular material radially outward to form a flange portion 42, and further reducing the diameter of the outboard portion 43 by drawing or the like to form a tapered portion 44a that gradually decreases in diameter towards the outboard side, thereby forming an intermediate material 40A. Next, as shown in Figure 3(b), the inner circumferential surface of the outboard portion 43, whose inner diameter has been reduced by drawing or the like, is shaved to make the inner diameter uniform over the entire width of the core metal 40.

[0035] Shaving is a process, as shown in Figure 4, in which an intermediate material 40A, which has a flange portion 42 and a tapered portion 44a formed thereon, is inserted into a hole 81 of a die 80 that is formed to conform to the shape of the outer surface of the intermediate material 40A, and then a punch 82 is inserted into the inner diameter hole of the intermediate material 40A to thin the inner surface (usually 3 to 10% of the core plate thickness). If the amount to be removed is insufficient in one process, the process can be repeated several times.

[0036] Furthermore, the inner circumferential surface of the core metal 40 after the tapered portion 44a is formed by drawing may be formed into a cylindrical shape by turning instead of shaving. In addition, the tapered portion 44a of the core metal 40 can also be formed by turning the outer circumferential surface of the annular core metal 40 on which the flange portion 42 is formed, in addition to the drawing process described above. In this case, shaving is not required.

[0037] As described above, the core metal 40 of the cap body 50 in this embodiment is provided with a tapered portion 44a whose outer diameter gradually decreases as it approaches the outboard side. As a result of the reduction in outer diameter due to the tapered portion 44a, the wall thickness t of the small-diameter cylindrical portion 51a can be increased. This mitigates the effect of changes in the tightening allowance of the cylindrical portion 51 (small-diameter cylindrical portion 51a) and maintains the watertight performance of the fitting portion. Furthermore, since the inner surface of the tapered portion 44a is formed in a cylindrical shape despite the outer surface being tapered, the installation position of the sensor 70 can be set further outward. This allows for a larger outer diameter of the magnetic encoder 14, contributing to improved magnetic flux density, improved accuracy of magnetic signals, and an increase in the number of poles.

[0038] [Second Embodiment] Next, the sensor holder cap 30 of the sensor-equipped hub unit bearing according to the second embodiment will be described with reference to Figure 5. In the cap 30 of the second embodiment, as shown in Figure 5(a), the thickness t1 of the outboard side end 43a of the core metal 40 is equal to the thickness of the inboard side portion of the main body 41. Furthermore, a small diameter portion 44b with an arc-shaped cross-section is provided in the outboard side portion 43 located on the inner diameter side of the inboard side end of the outer ring 2, away from the outboard side end 43a. The small diameter portion 44b is formed by being recessed from the outer circumferential surface of the outboard side portion 43.

[0039] This makes it possible to increase the wall thickness t of the small-diameter cylindrical portion 51a formed on the outer diameter side of the small-diameter portion 44b, thereby mitigating the effects of changes in the clamping allowance of the cylindrical portion 51. Furthermore, since the thickness t1 of the outboard side end 43a of the core metal 40 is greater than the thickness t1 of the outboard side end 43a of the tapered portion 44a in the first embodiment, the flow of molten resin can be stopped at the end face of the outboard side end 43a when molding the cap body 50, and flashing of molten resin into the inner circumferential surface of the core metal 40 can be prevented.

[0040] As a method for forming the small-diameter portion 44b with a circular arc cross-section, as shown in Figure 5(b), an intermediate material 40A is formed by applying plastic deformation, such as rolling, to the portion of the outboard side portion 43 of the core metal 40 that is away from the outboard side end 43a. Due to the plastic deformation, the inner diameter side portion of the small-diameter portion 44b protrudes. This protruding inner diameter side portion is removed by shaving or turning, as shown in Figure 5(c), similar to the first embodiment. The small-diameter portion 44b can also be formed by turning in addition to plastic deformation. In this case, shaving of the inner diameter side portion of the small-diameter portion 44b is unnecessary.

[0041] Furthermore, the thickness t1 of the outboard side end 43a of the core metal 40 is equal to the thickness of the inboard side portion of the main body portion 41, and the small diameter portion 44b is formed in the portion located on the inner diameter side of the inboard side end of the outer member, but the small diameter portion 44b may have a different shape.

[0042] For example, Figure 6(a) shows a modified example in which a small-diameter portion 44c with a substantially rectangular cross-section is formed in the outboard portion 43 of the core metal 40, away from the outboard end 43a. The small-diameter portion 44c with a substantially rectangular cross-section can be formed by a combination of plastic deformation such as rolling and shaving, or a combination of plastic deformation and turning, as shown in Figures 6(b) and (c), similar to the core metal 40 of the second embodiment. Furthermore, it can also be formed by turning, which turns the small-diameter portion 44c with a substantially rectangular cross-section.

[0043] In the modified core metal 40, where the shape of the small diameter portion 44c is approximately rectangular in cross-section, the axial length of the wall thickness t portion of the small diameter cylindrical portion 51a can be increased, further mitigating the effects of changes in the clamping allowance of the cylindrical portion 51.

[0044] Figure 7 shows a modified example in which a comb-shaped small-diameter portion 44d is formed on the outboard side portion 43 of the core metal 40 by turning. The turning of the small-diameter portion 44d is performed from a portion away from the outboard side end 43a. With this modified core metal 40, since the small-diameter portion 44d has a comb-shaped cross-section, the bonding strength between the core metal 40 and the small-diameter cylindrical portion 51a is improved.

[0045] Furthermore, the present invention is not limited to the embodiments described above, and can be modified, improved, etc., as appropriate. For example, in the above embodiment, the inner circumferential surface of the core metal 40 has a uniform inner diameter over its entire width. However, the present invention is not limited to this, and as shown in Figure 8, the outboard side of the core metal 40 may have a uniform inner diameter, while the inboard side may have an inner diameter that is wider than that of the outboard side.

[0046] As described above, the following matters are disclosed in this specification: (1) An outer member having a double row of outer ring raceways on its inner circumferential surface, An inner member having a wheel mounting flange on the outboard side and having a double row of inner ring raceways on its outer circumferential surface that are opposite to the double row of outer ring raceways, A plurality of rolling elements are arranged to roll freely between the double-row outer ring raceway and the double-row inner ring raceway, A magnetic encoder fixed to the inboard-side end of the inner member, A cap with a sensor holder is fitted and fixed to the inner circumferential surface of the inboard-side end of the outer member, which closes the inboard-side opening of the outer member and holds a sensor for detecting changes in the magnetic poles of the magnetic encoder. A sensor-equipped hub unit bearing comprising, The sensor holder cap comprises a metal annular core, a cylindrical portion made of synthetic resin integrally formed on the outer diameter side of the core and fitted and fixed to the inner circumferential surface of the inboard end of the outer member, and a sensor housing portion capable of housing the sensor so that the sensor faces the magnetic encoder. The core metal extends inwards from the portion located on the inner diameter side of the inboard end of the outer member, The core metal has a small-diameter portion located on the inner diameter side of the inboard end of the outer member, the portion whose outer diameter is smaller than the outer diameter of the cylindrical portion extending toward the inboard side. The inner circumferential surface of the core metal has a uniform inner diameter over the entire width of the core metal, or an inner diameter that is widened on the inboard side. Hub unit bearing with sensor. With this configuration, the resin thickness of the cylindrical part into which the core metal is insert-molded can be increased, mitigating the effects of changes in the interference fit of the cylindrical part and maintaining good watertight performance.

[0047] (2) The small diameter portion is formed such that the outer surface of the core metal gradually becomes smaller in diameter as it approaches the outboard side. (1) Hub unit bearing with sensor as described above. This configuration allows for the easy formation of a small-diameter portion on the outer surface of the core.

[0048] (3) The small diameter portion is formed in a recess from the outer circumferential surface of the outboard side end, on the inboard side of the outboard side end. (1) Hub unit bearing with sensor as described above. This configuration ensures sufficient thickness at the outboard end of the core, preventing flash from occurring during injection molding, where molten resin flows into the inner surface of the core. [Explanation of Symbols]

[0049] 1. Hub unit bearing with sensor 2. Outer ring (outer member) 2a Inner circumferential surface of the inboard-side end of the outer member 3. Hub (internal member) 4 Rolling elements 8a, 8b Outer ring raceway 11 Wheel mounting flange 12a, 12b Inner ring track 14 Magnetic Encoder 30 Caps (Caps with Sensor Holders) 40 Mandrel 43 Outboard side section 43a Outboard side end 44a Tapered section (small diameter section) 44b, 44c, 44d Small diameter section 51 Cylindrical part 51a Small diameter cylindrical section 54 Sensor housing 70 sensors

Claims

1. An outer member having double rows of outer ring raceways on its inner circumferential surface, An inner member having a wheel mounting flange on the outboard side and having a double row of inner ring raceways on its outer circumferential surface that are opposite to the double row of outer ring raceways, A plurality of rolling elements are arranged to roll freely between the double-row outer ring raceway and the double-row inner ring raceway, A magnetic encoder fixed to the inboard-side end of the inner member, A cap with a sensor holder is fitted and fixed to the inner circumferential surface of the inboard-side end of the outer member, closing the inboard-side opening of the outer member, and holding a sensor for detecting the magnetic pole change of the magnetic encoder. A sensor-equipped hub unit bearing comprising, The sensor holder cap comprises a metal annular core, a cylindrical portion made of synthetic resin integrally formed on the outer diameter side of the core and fitted and fixed to the inner circumferential surface of the inboard end of the outer member, and a sensor housing portion capable of housing the sensor so that the sensor faces the magnetic encoder. The core metal extends inwards from the portion located on the inner diameter side of the inboard end of the outer member, The core metal has a small-diameter portion located on the inner diameter side of the inboard end of the outer member, the portion whose outer diameter is smaller than the outer diameter of the cylindrical portion extending toward the inboard side. The inner circumferential surface of the core metal has a uniform inner diameter over the entire width of the core metal, or an inner diameter that is widened on the inboard side. Hub unit bearing with sensor.

2. The small-diameter portion is formed in such a way that the outer surface of the core metal gradually becomes smaller in diameter as it approaches the outboard side. A sensor-equipped hub unit bearing according to claim 1.

3. The small diameter portion is formed by being recessed from the outer circumferential surface of the outboard side end, on the inboard side of the outboard side end. A sensor-equipped hub unit bearing according to claim 1.

Images