JP7684843B2 - Wheel bearing device with rotation sensor for outer ring rotation - Google Patents

Description

The present invention relates to a wheel bearing device with a rotation sensor for outer ring rotation, which has a rotation sensor that supports a wheel and measures the rotation speed of the outer ring that rotates together with the wheel.

Large dump trucks and the like use multiple bearings, such as tapered roller bearings with outer rings that support the wheels and rotate with the wheels. For example, the bearing described in Patent Document 1 has been known as this type of bearing.

Patent No. 5687537

Whereas bearings having a rotation sensor that measures the rotation speed of the outer ring have been used in the past, Patent Document 1 does not disclose the detailed structure of the rotation sensor, nor the detailed structure of the pulser ring used to detect the rotation speed of the outer ring. As a result, there is no description of the wiring of the rotation sensor, and it is only stated that the rotation sensor is attached to the inboard bearing of the multiple bearings. Here, the inboard side refers to the side that is closer to the center in the left-right direction of the vehicle (vehicle width direction) when the bearing is installed on the vehicle. The opposite term, the outboard side, refers to the side that is closer to the outside in the left-right direction of the vehicle when the bearing is installed on the vehicle.

If a bearing with a rotation sensor is placed on the inboard side, the labor required to replace the sensor in the event of a sensor failure increases. This is because the work must be done in the center of the vehicle and the bearing on the outboard side must be removed. In the case of a large dump truck, the labor and time required for the replacement are significant, and the labor costs for replacement are very high.

In addition, many of these bearing lubrication methods involve an oil bath, and when the outer ring rotates, the lubricating oil may get on the rotation sensor. Lubricating oil often contains sulfur, which can react with the copper in the rotation sensor or electric wire to produce copper sulfide. In other words, when immersed in lubricating oil, the sulfur and copper react through chemical attack to produce copper sulfide, which can cause a short circuit between terminals such as electrodes and lead to malfunction. For this reason, commercially available connectors that connect sensors and electric wires generally cannot be used in oil. On the other hand, connectors with good oil and heat resistance that can be used in oil are expensive, and inexpensive connectors cannot be used as is as mentioned above, so some ingenuity is required to use them.

The object of the present invention is to provide a wheel bearing device with a rotation sensor for outer ring rotation that can solve the problems of the conventional technology described above, reduce the labor and time required for replacement, reduce replacement labor costs, and can be used inexpensively even with an oil bath lubrication method.

In order to achieve the above object, a wheel bearing device with a rotation sensor for outer ring rotation according to the present invention comprises:
A wheel bearing device with a rotation sensor for outer ring rotation, comprising a plurality of bearings each having an inner ring attached to a fixed member, a rolling element, and an outer ring rotatably supported by the inner ring via the rolling element and rotating together with a wheel,
a rotation sensor attached to an outboard bearing of the plurality of bearings to detect the rotation speed of the outer ring of the bearing, a pulser ring attached to the outer ring to detect the rotation speed of the outer ring in cooperation with the rotation sensor, and a harness electrically connected to the rotation sensor,
The rotation sensor is attached inside the wheel, the harness is directly connected to the rotation sensor, and the directly connected joint is covered with a sealing member.

According to the above configuration, the wheel bearing device with a rotation sensor for outer ring rotation of the present invention has a rotation sensor that detects the rotation speed of the outer ring of the bearing attached to the outboard bearing of the multiple bearings, so the detailed structure of the rotation sensor is clearly visible, and the labor and time required for replacing the rotation sensor can be reduced, thereby reducing replacement labor costs. In addition, the wheel bearing device with a rotation sensor for outer ring rotation of the present invention directly connects the rotation sensor to the harness (also called electric wire or wiring) and covers the connection (joint) with the sealing member, so the wiring of the rotation sensor is clearly visible, preventing the intrusion of lubricating oil, and preventing lubricating oil from adhering to the connection and harness. This makes it possible to use the device at low cost even with an oil bath lubrication method. The sealing member may be, for example, epoxy resin, or a cover part that covers the joint, which will be described later.

the sealing member covering the joint portion is a cover part partially covering the joint portion,
The cover part is composed of a cover body and a cover lid, and the cover body and the cover lid may be formed in an engaging shape and fixed with an adhesive to prevent the infiltration of liquids such as oil into the inside of the cover part. In this way, the infiltration of lubricating oil can be prevented by adhering the joint surfaces of the cover body and the cover lid with an adhesive such as resin, and further by filling the inside of the cover part with a filler using resin to cover the inside of the cover part, particularly the joint part between the harness and the rotation sensor.

The adhesive is an epoxy resin, and the cover lid may be provided with a hole in case the adhesive or the epoxy resin filler leaks out. Epoxy resin expands in volume when cured from a high temperature state, which can cause the harness to break or be pushed out of the cover part. Therefore, by providing the hole in the cover lid, the expanded epoxy resin can flow out, preventing such phenomena from occurring.

The rotation sensor may be fixed to a bracket with a bolt, and the bracket may be positioned by the inner ring of the bearing. This allows the rotation sensor to be attached to the inner ring in an accurately positioned state. The bracket may also be positioned by the outer diameter surface of the inner ring and fixed in a tapped hole in the width surface of the inner ring, and the bolt may be fixed with an anti-loosening adhesive. This allows the bracket fixing structure to be simplified.

The hole in the pulsar ring may be an elongated hole that is long in the axial direction when viewed from the radial direction. This allows the detailed structure of the pulsar ring to be clearly seen, and the rotation speed of the outer ring can be reliably detected.

The rotation sensor may be attached to the top side of the bearing shaft in the vertical direction. As described above, the rotation sensor is attached to the inside of the wheel in the radial direction, and this structure makes it possible to prevent the rotation sensor from being immersed in lubricating oil.

The rotation sensor and the harness may be fastened together by a connector, and part or all of the connector may be bonded with an adhesive or coated with resin. This method also prevents the infiltration of lubricating oil, as in the above case, and allows the bearings to be used inexpensively even when lubricated by oil bath.

The wheel bearing device with a rotation sensor for outer ring rotation according to the present invention reduces the labor and time required for replacement, reducing replacement labor costs, and can also be used inexpensively with an oil bath lubrication method.

1 is a vertical cross-sectional view showing a wheel drive device equipped with a wheel bearing device with a rotation sensor for outer ring rotation according to an embodiment of the present invention. 2 is an enlarged vertical cross-sectional view of the periphery of a wheel bearing device with a rotation sensor for outer ring rotation of the wheel drive device shown in FIG. 1 . 2 is a perspective view showing the configuration of an inner ring, an outer ring, a pulsar ring, a rotation sensor, etc. of the wheel bearing device with a rotation sensor for outer ring rotation. FIG. 4 is an enlarged front view of the rotation sensor and its periphery in FIG. 3 as viewed in the axial direction. FIG. 2 is a perspective view of the entire rotation sensor (without a cover). FIG. 2 is a perspective view of the entire rotation sensor (with a cover); FIG. 4 is a perspective view of the entire rotation sensor (another example with a lid); FIG. 13 is a perspective view of the entire rotation sensor of another example different from the above (without the cover).

The following describes an embodiment of the present invention with reference to the drawings. FIG. 1 shows a wheel drive device 100 for a large dump truck, for example. As shown in the figure, a fixed spindle 1 as an axle is fixed to a fixed member of a vehicle body (including suspension frame parts such as knuckles) not shown. On the outer diameter surface of the fixed spindle 1, a plurality of bearings Bn constituting a wheel bearing device BA with a rotation sensor for outer wheel rotation of this embodiment are attached at intervals in the axial direction, namely, rolling bearings B1 and B2, and in this embodiment, a wheel (including a wheel or more specifically, a wheel housing) 2 having two rows of tires 3 is rotatably supported by the rolling bearings B1 and B2.

A motor 4 for driving the wheel 2 is provided on the inboard side of the fixed spindle 1, and a drive shaft 5 driven and rotated by the motor 4 as a drive source is inserted into the fixed spindle 1 and arranged coaxially with the fixed spindle 1. A reduction mechanism 10 for reducing the rotation of the drive shaft 5 and transmitting it to the wheel 2 is provided on the outboard side of the fixed spindle 1. The reduction mechanism 10 is composed of a first planetary gear type reduction mechanism 10a and a second planetary gear type reduction mechanism 10b.

The first planetary gear reduction mechanism 10a is composed of a sun gear 11a fixed to the shaft end of the drive shaft 5, a planetary gear 12a meshing with the sun gear 11a, and an internal gear 13a meshing with the planetary gear 12a. The rotation of the sun gear 11a is transmitted from the planetary gear 12a to the internal gear 13a, and the cylindrical gear coupling 14 connected to the internal gear 13a is rotated at a reduced speed. On the other hand, the second planetary gear reduction mechanism 10b is composed of a sun gear 11b fitted into the end of the gear coupling 14 and splined, a planetary gear 12b meshing with the sun gear 11b, and an internal gear 13b meshing with the planetary gear 12b. The rotation of the sun gear 11b is transmitted from the planetary gear 12b to the internal gear 13b, and the wheel 2 to which the internal gear 13b is fixed is rotated at a reduced speed.

Here, the carrier 13c that rotatably supports the planetary gear 12b of the second planetary gear reduction mechanism 10b has a cylindrical portion 13d at its end, and the cylindrical portion 13d is fitted into the outboard end of the fixed spindle 1 and splined. The internal gear 13b of the second planetary gear reduction mechanism 10b is connected to the outboard end of the wheel 2, and an enclosed space 16 is formed in the wheel 2 by a wheel cap 15 attached to the outboard end face of the internal gear 13b. Oil is stored in the enclosed space 16, and the reduction mechanism 10 is lubricated by the oil. Note that, although a planetary gear reduction mechanism is used as the reduction mechanism 10 in the embodiment, the reduction mechanism 10 is not limited to a planetary gear reduction mechanism, and any well-known reduction mechanism can be used.

As shown in FIG. 2, the rolling bearings B1 and B2 that support the wheel 2 rotatably are tapered roller bearings that are composed of at least an inner ring 21 attached to the fixed member (spindle 1 in the figure) not shown, tapered rollers 22 as rolling bodies, and an outer ring 20 that is rotatably supported by the inner ring 21 via the tapered rollers 22 and rotates with the wheel 2, and further composed of a retainer 23 that holds the tapered rollers 22. These tapered roller bearings B1 and B2 are back-to-back assembled (DB set) and support the wheel 2 rotatably. The inner ring 21, tapered rollers 22 and outer ring 20 are crowned at both ends, and the tapered roller bearings B1 and B2 are set with a fixed position preload. The tapered roller bearings B1 and B2 and the reduction mechanism 10 are lubricated by the oil stored in the sealed space 16 in the wheel 2, and each of the tapered roller bearings is equipped with a single seal.

In this embodiment, the tapered roller bearing B1, which is located on the outboard side of the tapered roller bearings B1 and B2, is a tapered roller bearing with a rotation sensor for outer ring rotation, which has a cylindrical pulsar ring 200 concentric with the end of the outer ring 20 and a rotation sensor 300 that detects the rotation speed of the outer ring 20 of the tapered roller bearing B1. As shown in FIG. 3, the pulsar ring 200 that cooperates with the rotation sensor 300 is provided with long holes HL, HL... that are long in the axial direction when viewed from the radial direction, and the rotation sensor 300 counts the number of times these long holes pass during rotation, thereby detecting the rotation speed of the outer ring 21. Note that in FIG. 3, the tapered rollers 22, the cage 23, the drive shaft 5, etc. are omitted from the illustration in order to make it easier to see. An electrically connected harness 400 extends from the rotation sensor 300 and extends toward the center of the vehicle body (inboard side) from a circular hole 21b formed in the (arbitrary shape) retaining cover 21a of the inner wheel 21, which is disc-shaped as shown in FIG. 4 (arrow LL in FIG. 1).

The rotation sensor 300 will now be described in detail. As described above, the rotation sensor 300 detects the rotation speed of the outer ring 20 of the outboard tapered roller bearing B1. The rotation sensor 300 may also detect the rotation speed of the wheel housing or the like. This rotation sensor 300 is attached to the inside of the wheel 2, not to the outside in the radial direction, and is further attached to the top side (upper side) in the vertical direction with respect to the rotation axis of the tapered roller bearing B1 (Figures 3 and 4). As shown in Figure 5, the rotation sensor 300 is composed of at least a rotation speed sensor element 301, an electric wire (harness) 400, and a cover part 303 that partially or entirely covers the joint between them.

The rotation sensor 300 is fixed to the bracket 500 shown in Figures 3 and 4 with bolts, and an anti-loosening adhesive (anaerobic sealant) is applied. The positioning reference for the bracket 500 is the inner ring 21 of the tapered roller bearing B1. The bracket 500 is positioned by the outer diameter surface of the inner ring 21 and fixed by a tapped hole in the width surface of the inner ring 21. The rotation sensor is attached near the top of the shaft so that it does not enter the lubricating oil when the vehicle is stopped. Generally, the amount of lubricating oil on a vehicle is near the shaft center.

As shown in FIG. 5, the harness 400 is directly connected to the rotation speed sensor element 301 of the rotation sensor 300, and the directly connected joint is covered with a sealing member. In this embodiment, the sealing member is a cover part 303 that is enclosed to cover the joint, but it may also be, for example, epoxy or the like that is filled inside the cover part. The cover part 303 consists of a cover body 305 and a cover lid 307 (FIG. 6), and the cover body 305 and the cover lid 307 are fixed (bonded) with an adhesive such as epoxy resin, and the inside of the cover part 303 is filled with a filler such as epoxy resin (not shown in the figure for ease of viewing). In the overall perspective view of FIG. 5, the cover lid 307 is omitted from the viewpoint of ease of viewing the inside, and FIG. 6 is a complete overall perspective view of the rotation sensor 300 to which the cover lid 307 is fixed. For example, the cover lid 307 has an engagement protrusion (not shown) formed integrally therewith, and the cover body 305 and the cover lid 307 are fitted together by a locking shape in which the engagement protrusion engages with an engagement recess (not shown) formed integrally with the cover body 305.

As shown in FIG. 7, the cover lid 307A is provided with a hole 307Aa in case the epoxy resin or the like leaks out. When epoxy resin hardens from a high temperature state, its volume expands, which can cause the harness to break or be pushed out of the cover. Therefore, by providing the hole 307Aa in the cover lid 307A, the expanded epoxy resin can flow out, preventing such a phenomenon from occurring.

As described above, in the wheel bearing device BA with a rotation sensor for outer ring rotation, the rotation sensor 300 that detects the rotation speed of the outer ring 20 of the bearing is attached to the outboard bearing B1 of the multiple bearings Bn, so the detailed structure of the rotation sensor is clearly visible, and the labor and time required for replacing the rotation sensor can be reduced, thereby reducing replacement labor costs. In addition, the wheel bearing device BA with a rotation sensor for outer ring rotation directly connects the rotation sensor 300 and the harness 400, and the connection (joint) is covered with the sealing member, so the description regarding the wiring of the rotation sensor 300 is clearly visible, it is possible to prevent the intrusion of lubricating oil, and lubricating oil does not adhere to the connection and harness 400, etc. This makes it possible to use it inexpensively even with an oil bath lubrication method. Furthermore, by bonding the joint surfaces of the cover body 305 and the cover lid 307 in the cover part 303 with an adhesive such as resin, and further by filling the inside of the cover part 303 with a filler and covering the inside of the cover part 303, particularly the joint part between the harness 400 and the rotation sensor 300, it is possible to prevent the infiltration of lubricating oil.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

For example, as shown in FIG. 8, in the above embodiment, the rotational speed sensor element 301 and the harness 400 may be connected by a connector 410. Also, a part or all of the connector 410 may be coated with a resin (e.g., an adhesive such as epoxy resin, or a filler). Note that the connector 410 and the like are covered by the cover body 305 and the cover lid 307 as in the above embodiment, but the figure does not show the cover lid 307 to make it easier to see inside.

21 Inner ring 22 Rolling element 2 Wheel 20 Outer ring B1, B2 (Rolling) bearing BA Wheel bearing device with rotation sensor for outer ring rotation Bn Plural bearings 300, 300A, 300B Rotation sensor 200 Pulsar ring 400 Harness 303 Cover part 305 Cover 307, 307A Cover lid 307Aa Hole 500 Bracket

Claims (5)

A wheel bearing device with a rotation sensor for outer ring rotation, comprising a plurality of bearings each having an inner ring attached to a fixed member, a rolling element, and an outer ring rotatably supported by the inner ring via the rolling element and rotating together with a wheel,
a rotation sensor attached to an outboard bearing of the plurality of bearings to detect the rotation speed of the outer ring of the bearing, a pulser ring attached to the outer ring to detect the rotation speed of the outer ring in cooperation with the rotation sensor, and a harness electrically connected to the rotation sensor,
The rotation sensor is attached inside the wheel, the harness is directly connected to the rotation sensor, and the directly connected joint portion is covered with a sealing member ,
The rotation sensor is fixed to a bracket by a bolt, and the bracket is positioned by the inner ring of the bearing;
The bracket is positioned on an outer diameter surface of the inner ring and fixed to the inner ring through a tapped hole in a width surface of the inner ring, and the bolt is fixed to the inner ring with a thread-locking adhesive.
Wheel bearing device with rotation sensor for outer ring rotation. 2. The wheel bearing device with a rotation sensor for outer ring rotation according to claim 1,
the sealing member covering the joint portion is a cover part partially covering the joint portion,
The cover part is composed of a cover body and a cover lid, and the cover body and the cover lid are formed in an engaging shape and fixed with an adhesive to prevent liquid from entering the inside of the cover part.
Wheel bearing device with rotation sensor for outer ring rotation. 3. The wheel bearing device with a rotation sensor for outer ring rotation according to claim 2,
The adhesive is an epoxy resin, and the cover lid is provided with a hole for leakage of the epoxy resin.
Wheel bearing device with rotation sensor for outer ring rotation. The wheel bearing device with a rotation sensor for outer ring rotation according to any one of claims 1 to 3 ,
The hole of the pulsar ring is an axially long hole when viewed in the radial direction.
Wheel bearing device with rotation sensor for outer ring rotation. The wheel bearing device with a rotation sensor for outer ring rotation according to any one of claims 1 to 4 ,
The rotation sensor is attached to the top side in the vertical direction with respect to the rotation shaft of the bearing.
Wheel bearing device with rotation sensor for outer ring rotation.

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