JP2023059707A - Rolling bearing with rotary sensor - Google Patents

Abstract

To secure a prescribed sensor output accuracy by allowing the output to be easily lead out to the outside while preventing damage and breakage of an output cable.SOLUTION: An opening part 14 continuing from a base end to a tip end of a cylindrical form is formed at a side face of a cylindrical lead out section 9a, integrally formed to a sensor housing 9, of an output cable 12. After passing the output cable 12 from the opening part 14 to the lead out section 9a, a slide type cover member 15 is attached to the opening part 14 so as to block the opening part 14 to prevent damage and breakage of the output cable 12 of a magnetic sensor, and thus the output cable 12 can be easily lead out to the outside. The plurality of magnetic sensors outputs inner signals having respective electric angle phase differences. The electric angle phase difference has a magnitude of 1/N of the wavelength, and a tolerance of 1/X of the electric angle phase difference. The plurality of magnetic sensors is arranged while apart from each other by a prescribed mechanical angle with respect to the number M of the pairs of magnetic poles of a magnetic encoder, and a mechanical angle Δ corresponding to the tolerance is not larger than a prescribed threshold Δt.SELECTED DRAWING: Figure 3

Description

The present invention relates to a rolling bearing with a rotation sensor.

2. Description of the Related Art A rolling bearing with a rotation sensor is sometimes used to detect the rotational speed (number of rotations) of a rolling bearing that supports a rotating shaft or the like of various rotating devices. In this rolling bearing with a rotation sensor, an annular magnetic encoder magnetized to alternately different magnetic poles in the circumferential direction is mounted on the rotating bearing ring side of the inner and outer rings. A sensor housing incorporating a magnetic sensor for detecting changes in magnetic flux is attached to the stationary race to detect the rotation of the rotating race. The sensor housing often also incorporates a circuit board that processes the output of the magnetic sensor. From the magnetic sensor, an absolute angle signal, also called an absolute signal corresponding to magnetic characteristics such as a change in magnetic flux, and two signals having an electrical angle phase difference of 90° and corresponding to the magnetic characteristics are transmitted via the circuit board. Either one or both of a relative angle signal (phase A signal, phase B signal), which is also called a pulsed incremental signal, is output.

Many of the sensor housings of such rolling bearings with rotation sensors are made of resin, and are attached to the stationary race through a metal outer ring. The resin-made sensor housing has a tube through which the output cable passes so that the output cable of the magnetic sensor, which is connected to the circuit board or the like in the sensor housing and taken out, is not damaged by shearing or the like, or disconnected. There is one in which a sensor housing is integrally formed with a shaped take-out portion (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2002-213472

The rolling bearing with a rotation sensor described in Patent Document 1 can prevent the damage or disconnection of the output cable of the magnetic sensor, but it is necessary to pass the output cable connected to the circuit board or the like in the sensor housing through a cylindrical extraction part. There is a problem that it takes time and effort to take out the output cable to the outside. Also, sensor output accuracy is not addressed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent the output cable of a magnetic sensor from being damaged or disconnected, and to allow the output cable to be easily taken out to the outside. Another object is to ensure a predetermined sensor output accuracy.

In order to solve the above problems, the rolling bearing with a rotation sensor of the present invention has:
An annular magnetic encoder magnetized with different magnetic poles alternately in the circumferential direction is provided on the rotating race side of the inner and outer races, and the magnetic encoder is provided on the fixed race side of the inner and outer races. a resin sensor housing in which a plurality of magnetic sensors for detecting changes in magnetic flux due to rotation of the resin sensor housing are incorporated; and a circuit board on which the plurality of magnetic sensors are mounted, a rolling bearing with a rotation sensor in which output cables from the plurality of magnetic sensors connected to the circuit board are formed in the rolling bearing,
Each of the plurality of magnetic sensors outputs an internal signal related to a change in the detected magnetic flux having an electrical angle phase difference with each other, the electrical angle phase difference being 1/N wavelength and the electrical angle phase difference [N, X are natural numbers],
The plurality of magnetic sensors are arranged apart by a mechanical angle θ represented by the following formula (1) with respect to the number M of pairs of magnetic poles of the magnetic encoder [M is a natural number], and the allowable value The mechanical angle Δ corresponding to is determined by the following formula (2), and the mechanical angle Δ is equal to or less than the predetermined threshold Δt.
θ=360/N/M×(1+kN) [k is an integer greater than or equal to 0] (1)
Δ=360/N/M/X (2)
A predetermined sensor output accuracy can be ensured by a plurality of magnetic sensors having the above configuration including the arrangement of the mechanical angle θ.

An open portion extending from the base end to the tip of the extraction portion is provided on the side surface of the extraction portion, and
a lid member that closes the opening, the output cable that extends from the circuit board to the take-out portion in the opening closed by the lid member, and an output cable on the tip end side of the take-out portion. and a caulking agent filled in the gap,
The caulking agent may contain at least vinylmethylsilicone rubber as a main component and silicon dioxide, and may have a tensile strength of 2 MPa or more and an elongation of 350% or more.

In other words, an opening extending from the proximal end to the distal end is provided on the side surface of the take-out portion, and after the output cable is passed through the take-out portion through the open portion, the opening is closed by attaching the cover member to the open portion. , the output cable of the magnetic sensor is prevented from being damaged or disconnected, and the output cable can be easily taken out to the outside.

By making the open part of the take-out part continuous from the proximal end to the distal end with a constant width, and by sliding the lid member to the open part of the equal width from the distal end side to the proximal end side, The open part of the extraction part can be easily closed. After the cover member is attached, the caulking agent is filled in the gap between the output cable and the tip of the closed take-out portion, thereby strengthening the attachment of the cover member by filling the caulking agent, and making it possible to easily take out the output cable from the outside. It is possible to achieve both the purpose of preventing damage or disconnection of the output cable and the purpose of easily closing the opening of the take-out portion by sliding the lid member. Before fixing the magnetic sensor, the circuit board, and the output cable in the sensor housing including the take-out portion with the thermosetting molding resin, the output cable 12 on the tip side of the take-out portion 9a and the output cable 12 are connected as described above. By filling the gap with a caulking agent, this gap contributes to preventing the output cable passed through the opening from rubbing when the cover member is slid into the opening. The caulking agent filled in the gap between and contributes to adhesion and fixation of the lid member. Therefore, there is an effect that the lid member that is slid and attached to the open portion is not easily removed. In addition, if the output cable is bent during use, the caulking agent can prevent contact between the tip inner edge of the sensor housing and the output cable, thereby preventing damage to the insulation coating of the output cable. . With the above-described configuration of the caulking agent, the elasticity of the caulking agent is effective, and when the output cable is bent, it is possible to prevent the output cable from being damaged at the edge portion of the tip of the take-out portion.

In the rolling bearing with a rotation sensor of the present invention, an opening extending from the base end to the tip is provided on the side surface of the output cable take-out portion formed in the sensor housing. Since the opening is closed by attaching the lid member to the opening, the output cable of the magnetic sensor can be easily taken out while preventing the output cable from being damaged or disconnected.

The open part of the take-out part is made to have a uniform width from the base end to the tip, and the lid member is attached to the open part of the same width by sliding it from the tip side to the base end side. The open part of the part can be easily closed. Moreover, a predetermined sensor output accuracy can be ensured by the plurality of magnetic sensors having the above configuration including the above arrangement.

Longitudinal sectional view showing an embodiment of a rolling bearing with a rotation sensor Cross-sectional view along the II-II line in Fig. 1 (a) and (b) are perspective views explaining a method of passing an output cable through the extraction part of the sensor housing in FIG.

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this rolling bearing with a rotation sensor is a deep groove ball bearing in which balls 3 are held by a retainer 4 between an inner ring 1 and an outer ring 2. A magnetic encoder 6 is mounted on one side of an inner ring 1 serving as a raceway ring, and a sensor housing 9 in which a magnetic sensor 7 and a circuit board 8 are incorporated is mounted on one side of an outer ring 2 opposite thereto. A seal member 5 for sealing the inside of the bearing is mounted on the side of the outer ring 2 opposite to the sensor housing 9 .

The magnetic encoder 6 is composed of an annular metal core 6a and a magnetic body 6b fixed to the outer diameter surface of the metal core 6a and magnetized to different magnetic poles alternately in the circumferential direction. is fitted and fixed to the outer diameter surface of the

The sensor housing 9 is made of a polymer alloy in which polyphenylene sulfide (PPS) is mixed with polyamide (PA) and polyimide (PI). It is covered with an outer ring 10 and a side ring 11 press-formed from a ferritic stainless steel plate SUS430. The sensor housing 9 is press-fitted into the inner diameter surface of the outer ring 10, the outer ring 10 is fitted and fixed to the inner diameter surface of the outer ring 2, and a seal portion 10a for sealing the inside of the bearing is formed on the inner end side thereof.

Since the polymer alloy obtained by mixing PA and PI with PPS forming the sensor housing 9 has a higher glass transition temperature than PPS alone, it is press-fitted and fixed due to the temperature change when the temperature drops from a high temperature state. Loosening with the outer ring 10 is unlikely to occur, and temperature creep can be suppressed.

The sensor housing 9 shown in FIG. 1 has an L-shaped cross-sectional shape along a plane including the rotating shaft (not shown) of the bearing, and the magnetic sensor 7 and the magnetic encoder 6 are arranged so as to face each other in the radial direction of the bearing. In addition, a recessed hole-like blind hole Ho that does not penetrate from one end face to the other end face of the sensor housing 9 in the direction of the rotation axis is provided, and the magnetic sensor 7 is placed in this blind hole Ho. is inserted into The magnetic sensor 7 is inserted into the blind hole Ho from the side opposite to the electrical connection terminals (legs 7a). Here, the blind blind hole Ho has such a depth that the magnetic sensor 7 is positioned at a position facing the magnetic encoder 6 in the radial direction. The magnetic sensor 7 is then inserted into a small through-hole (not shown) provided in a circuit board 8 made of glass-filled epoxy resin, and then placed on the surface of the circuit board 8 opposite to the insertion side. soldered. That is, the thickness direction of the circuit board 8 is perpendicular to the detection direction of the magnetic sensor 7 (the direction of the magnetic field from the magnetic body 6b). Therefore, the magnetic sensor 7 can be mounted on the surface of the circuit board 8 facing the magnetic encoder 6, but in this embodiment, the magnetic sensor 7 is not mounted on the surface facing the magnetic encoder 6. . With this structure, the axial dimension of the sensor housing 9 around the magnetic sensor 7 can be made smaller, and the sensor housing 9 can be made compact.

As shown in FIGS. 1 and 2, there are a plurality of magnetic sensors 7. For example, the magnetic sensors 7 of the present embodiment are provided at two positions adjacent to each other in the circumferential direction of the sensor housing 9 (hereinafter referred to as magnetic sensor 71 and 72), which are arranged so as to face the magnetic encoder 6 in the radial direction and are connected to the circuit board 8 at the legs 7a. The output cable 12 of the magnetic sensor 7 connected to the circuit board 8 is It is taken out to the outside through a cylindrical take-out portion 9a integrally formed with the sensor housing 9. As shown in FIG. The magnetic sensor 7 , circuit board 8 and output cable 12 within the sensor housing 9 are fixed with a mold resin 13 . The reason why the two magnetic sensors 7 (71, 72) are arranged close to each other in the circumferential direction is to detect the direction of rotation from the difference between the detection outputs of the two. This is explained below.

Since the relative positional accuracy of the two magnetic sensors 71 and 72 arranged close to each other in the circumferential direction affects the sensor output accuracy, the relative positions (angles) of these two magnetic sensors 71 and 72 are determined in advance. It must be set well. That is, the relative positions (angles) of the two blind holes Ho, which are provided in the sensor housing 9 made of thermoplastic resin and into which the magnetic sensors 71 and 72 are inserted, must be provided with high accuracy in advance. be. The two magnetic sensors 71 and 72 each detect a change in the magnetic flux accompanying the rotation of the magnetic encoder 6, and have the detection output shifted from each other, that is, have an electrical angle phase difference with each other. Output a signal. The electrical angle phase difference corresponds to 1/N wavelength and has an allowable value of 1/X of the electrical angle phase difference [N and X are natural numbers]. In this embodiment, the magnetic sensor 71 outputs a so-called A-phase signal, and the magnetic sensor 72 outputs a so-called B-phase signal. The A phase signal and the B phase signal have a phase difference of 90 degrees in electrical angle between them, and the electrical angle phase difference is a pulse-like incremental signal corresponding to 1/4 wavelength (N=4). be. In this embodiment, the electrical angle phase difference has an allowable value of 1/2 (X=2) of the electrical angle phase difference, and has an allowable value of 45° in electrical angle. . In terms of sensor output accuracy, the accuracy of the relative phase difference between the output pulse waveforms of the A-phase signal and the B-phase signal must be guaranteed.

The plurality of magnetic sensors 7 are separated by a mechanical angle θ represented by θ=360/N/M×(1+kN) with respect to the number M of pairs of magnetic poles (N pole and S pole) of the magnetic encoder 6. placed. M can take any natural number. Although 64 poles are exemplified in this embodiment, the present invention is not limited to this. k can take any natural number. Since the error range of the mechanical angle increases as the distance between the sensors increases, it is desirable to set the range from 1 to 10. 1/N represents the wavelength, and although 1/4 is exemplified in this embodiment, it can be set in the range of 1/8 to 1/2. Also, the mechanical angle (that is, the allowable mechanical angle to the mechanical angle θ) Δ corresponding to the allowable value is determined by Δ=360/N/M/X, and the mechanical angle Δ is equal to or less than the predetermined threshold Δt. There is a need. X can take any value, but is preferably 10 or less. In this embodiment, the two magnetic sensors 71 and 72 are connected to the magnetic poles of the magnetic encoder 6 (128 poles in this embodiment) so that the A-phase signal and the B-phase signal having a phase difference of 90 electrical degrees are output. ), which is the number of pairs of 64 (M = 64). , k=0, they are spaced apart by θ=1.40625 (≈1.4°). Even if k=1, 2, . , there is no effect on the 90° phase difference because the electrical angle is only an integral multiple of 360°. The mechanical angle Δ corresponding to the allowable value of the present embodiment is Δ=360/4/64/2≈0.7, and for example, when the threshold Δt=0.7, Δ≦Δt is satisfied. As in this example, the accuracy of the relative phase difference between the output pulse waveforms is guaranteed for the A-phase signal and the B-phase signal, and the relative angular relationship between the two magnetic sensors 71 and 72 is ensured. can be done. Note that θ and Δ can be set arbitrarily.

As shown in FIG. 3(a), the take-out portion 9a of the sensor housing 9 is provided with an open portion 14 extending from the base end to the tip end of a cylindrical shape with an equal width on the side surface. The lid member 15 is attached to the open portion 14 after passing through the extraction portion 9a. The lid member 15 is made of the same polymer alloy as the sensor housing 9, and as shown in FIG. , to close the opening 14 by sliding it toward the base end side and pressing it against the inner end surface 16a of the groove 16. As shown in FIG.

After that, a caulking agent such as silicone is filled in the gap between the output cable 12 on the tip side of the take-out portion 9a, and a thermosetting resin such as epoxy resin or urethane resin is filled in the sensor housing 9 including the take-out portion 9a. is filled with the mold resin 13 and the lid member 15 is adhered and fixed to the sensor housing 9 . The caulking agent is, for example, composed of at least vinyl methyl silicone rubber as a main component to which silicon dioxide is added. The caulking agent has a tensile strength of 2 MPa or more and an elongation of 350% or more. With this configuration, the elasticity of the caulking agent works well, and when the output cable 12 is bent, it is possible to prevent the output cable 12 from being damaged at the edge portion of the tip of the tubular take-out portion 9a.

In the above-described embodiment, the rolling bearing is a deep groove ball bearing whose inner ring is a rotating raceway ring, but the rolling bearing with a rotation sensor according to the present invention can also be applied to other types of rolling bearings such as roller bearings. can be done. The present invention can also be applied to rolling bearings in which the outer ring is a rotating bearing ring. In this case, the magnetic encoder of the rotation sensor can be attached to the outer ring side, and the sensor housing incorporating the magnetic sensor can be attached to the inner ring side.

1 inner ring 2 outer ring 3 ball 4 retainer 5 seal member 6 magnetic encoder 6a core metal 6b magnetic body 7 magnetic sensor 7a leg portion 8 circuit board 9 sensor housing 9a extraction portion 10 outer ring 10a seal portion 11 side ring 12 output cable 13 mold Resin 14 Open portion 15 Lid member 15a Overhanging portion 16 Groove 16a Back end surface

Claims (3)

An annular magnetic encoder magnetized with different magnetic poles alternately in the circumferential direction is provided on the rotating race side of the inner and outer races, and the magnetic encoder is provided on the fixed race side of the inner and outer races. a resin sensor housing in which a plurality of magnetic sensors for detecting changes in magnetic flux due to rotation of the resin sensor housing are incorporated; and a circuit board on which the plurality of magnetic sensors are mounted, a rolling bearing with a rotation sensor in which output cables from the plurality of magnetic sensors connected to the circuit board are formed in the rolling bearing,
Each of the plurality of magnetic sensors outputs an internal signal related to a change in the detected magnetic flux having an electrical angle phase difference with each other, the electrical angle phase difference being 1/N wavelength and the electrical angle phase difference [N, X are natural numbers],
The plurality of magnetic sensors are arranged apart by a mechanical angle θ represented by the following formula (1) with respect to the number M of pairs of magnetic poles of the magnetic encoder [M is a natural number], and the allowable value is determined by the following formula (2), and the mechanical angle Δ is equal to or less than a predetermined threshold value Δt.
θ=360/N/M×(1+kN) [k is an integer greater than or equal to 0] (1)
Δ=360/N/M/X (2) An open portion extending from the base end to the tip of the extraction portion is provided on the side surface of the extraction portion, and
a lid member that closes the opening, the output cable that extends from the circuit board to the take-out portion in the opening closed by the lid member, and an output cable on the tip end side of the take-out portion. and a caulking agent filled in the gap,
2. The rolling bearing with a rotation sensor according to claim 1, wherein the caulking agent contains at least vinyl methyl silicone rubber as a main component and silicon dioxide is added, and has a tensile strength of 2 MPa or more and an elongation of 350% or more. Grooves are provided on both sides of the open portion, projecting portions are provided on both sides of the lid member, and the projecting portions on both sides of the lid member are fitted into the grooves on both sides from the distal end side, and are slid to the proximal end side. 3. A rolling bearing with a rotation sensor according to claim 1, wherein said rolling bearing is mounted so as to close said open portion by being pressed against the inner end face of said groove.

Images