JP6968038B2 - Rotation detector - Google Patents

Description

The present invention relates to a rotation detection device that detects the rotation speed of a rotating body.

As a device of this type, a device for detecting the rotation of a rotating shaft by detecting a magnetic change generated with the rotation of a rotor of a ring-shaped magnetic material is conventionally known (for example, Patent Document 1). reference). In the device described in Patent Document 1, a magnetic sensor is installed facing the outer peripheral surface of a rotor made of a magnetic material, and an elastic body is attached to the tip of the magnetic sensor in a state of being in constant contact with the outer peripheral surface of the rotor. The elastic body slides on the outer peripheral surface of the rotor to remove iron powder and the like adhering to the outer peripheral surface of the rotor.

Japanese Unexamined Patent Publication No. 6-109794

However, in the device described in Patent Document 1, since the elastic body constantly slides on the outer peripheral surface of the rotor, the elastic member is worn and the durability of the device is lowered.

One aspect of the present invention is a rotation detection device that detects the rotation speed of a rotating body arranged inside a housing in which lubricating oil is stored, and the tip portion thereof is installed away from the peripheral surface of the rotating body. It has a sensor body that generates a pulse signal according to the change in magnetic flux due to the rotation of the rotating body, and a cover part that covers the tip of the sensor body, and is substantially perpendicular to the axis passing through the center of the tip of the sensor body. A movable body supported by a sensor body is provided so as to be movable in a predetermined direction substantially perpendicular to the rotation axis of the rotating body. The movable body further has a pressure receiving portion to which the lubricating oil scraped up by the rotation of the rotating body hits, and is provided so as to move in a predetermined direction by the hydraulic pressure acting on the pressure receiving portion.

According to the present invention, it is possible to prevent foreign matter such as iron powder from adhering to the tip of the sensor body without deteriorating the durability of the device, and it is possible to detect rotation with high accuracy.

The figure which shows typically the example which attached the sensor main body of the rotation detection apparatus which concerns on embodiment of this invention around the differential apparatus. The perspective view of the sensor main body constituting the rotation detection apparatus which concerns on embodiment of this invention. The perspective view of the movable body which comprises the rotation detection apparatus which concerns on embodiment of this invention. Figure IV of the arrow in FIG. The figure which shows typically an example of the operation of the rotation detection device which concerns on embodiment of this invention when a vehicle is stopped. The figure which shows typically an example of the operation of the rotation detection apparatus which concerns on embodiment of this invention at the time of a vehicle running.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5B. The rotation detection device according to the embodiment of the present invention can be used as a vehicle speed detection device for detecting the traveling speed (vehicle speed) of the vehicle. This rotation detection device has a non-contact sensor body arranged around a rotating body that rotates at a rotation speed that correlates with the vehicle speed.

FIG. 1 is a diagram schematically showing an example of application of the rotation detection device 100 according to the embodiment of the present invention to a vehicle, that is, an example in which the rotation detection device 100 is provided around the differential device 2. Torque from a drive source (for example, an engine) (not shown) is transmitted to the differential device 2 via a transmission. As the drive source, a traveling motor may be used instead of the engine or in addition to the engine. The torque transmitted to the differential device 2 is transmitted to the left and right wheels via left and right drive shafts (not shown).

As shown in FIG. 1, the differential device 2 is rotatably arranged in the accommodation space SP1 in the transmission case 3. Although not shown, the differential device 2 is arranged in a differential case and a differential case in which torque from a transmission is input via a ring gear, and a pair of left and right side gears connected to left and right drive shafts, left and right, respectively. It has a pair of pinions that mesh with each pair of side gears, a pinion shaft that rotatably supports the pair of pinions from the differential case, and the like. The configuration of the differential device 2 is not limited to that described above, and may be, for example, a configuration having two pairs of pinions, a helical gear shaft LSD having no pinions, or the like.

The rotating body 5 is made of a metal which is a ferromagnetic material, and is provided integrally and coaxially with, for example, a differential case. More specifically, the rotating body 5 is supported by a rotating shaft 6 fixed to the transmission case 3 and rotates integrally with the differential case around the rotating shaft 6. In particular, when the vehicle moves forward, the rotating body 5 and the rotating shaft 6 rotate in the direction of the arrow R. The outer peripheral surface of the rotating body 5 is formed in an uneven shape over the entire circumference. That is, on the outer peripheral surface, concave portions and convex portions are regularly provided alternately in the circumferential direction and at equal intervals, and the uneven portions 5a are formed.

Lubricating oil is stored in the bottom of the accommodation space SP1 in the transmission case 3. The oil level OL of the lubricating oil is located higher than the bottom of the rotating body 5, and a part of the rotating body 5 is immersed in the lubricating oil. For example, the oil level OL is located below the horizontal line passing through the rotation axis 6. The lubricating oil is scraped up by the uneven portion 5a as the rotating body 5 rotates, and is scattered in the accommodation space SP1. The lubricating oil is also scraped up by the rotation of the differential device 2 (for example, the differential case) and supplied to each part of the differential device 2.

The rotation detection device 100 moves to the sensor body 10 extending around the axis CL1 and the tip of the sensor body 10 in a direction substantially perpendicular to the axis CL1 and substantially perpendicular to the rotation axis (arrow A direction). It has a movable body 20 provided as possible, and is configured as a rotation detection unit. The arrow A direction corresponds to the tangential direction with respect to the outer peripheral surface of the rotating body 5 at the intersection of the axis CL1 and the outer peripheral surface of the rotating body 5.

The sensor main body 10 is arranged so as to face the outer peripheral surface (concave and convex portion 5a) of the rotating body 5. That is, the sensor main body 10 is arranged so that one end (tip) thereof faces downward or diagonally downward along the axis CL1 at a predetermined distance from the outer peripheral surface of the rotating body 5, and the other end (base end). However, it is fixed to the transmission case 3 by a bolt or the like (not shown). More specifically, the tip of the sensor body 10 passes above the oil level OL of the lubricating oil, preferably above the horizontal line passing through the rotation axis 6, and passes through the rotation axis 6 in the rotation direction (arrow R direction). It is arranged in the range θ extending to the vertical line.

The sensor body 10 is configured as a pickup sensor having, for example, a permanent magnet and a coil. That is, the sensor main body 10 has a coil arranged around a permanent magnet arranged at the center thereof, and the coil is caused by a magnetic flux change accompanying the rotation of the rotating body 5, that is, a magnetic flux change caused by the passage of the uneven portion 5a. Generates a pulse signal with. The pulse signal generated by the sensor body 10 is output to a control unit (not shown), whereby the vehicle speed is detected.

By the way, since the sensor main body 10 has a magnet, foreign matter such as iron powder may adhere to the sensor main body 10 due to magnetic force. When iron powder adheres to the tip of the sensor body 10, the magnetic field around the sensor body 10 is affected, so that the vehicle speed detection accuracy is lowered. Therefore, in the present embodiment, the movable body 20 is provided at the tip of the sensor body 10 as follows so that foreign matter such as iron powder adhering to the sensor body 10 can be easily removed.

FIG. 2 is a perspective view of the sensor main body 10, and FIG. 3 is a perspective view of the movable body 20. In the following, for convenience, the front-back direction, the left-right direction, and the up-down direction are defined as shown in the figure, and the configuration of each part will be described according to these definitions. The front-back direction is the moving direction of the movable body 20 (direction of arrow A in FIG. 1), the left-right direction is the extending direction of the rotation axis 6 in FIG. 1, and the vertical direction is the direction along the axis CL1. In FIG. 3, the sensor main body 10 is shown by a two-dot chain line.

As shown in FIG. 2, the sensor main body 10 has a cylindrical portion 11 extending in the vertical direction about the axis CL1 and a base portion 12 provided at the lower end portion of the cylindrical portion 11. A flange portion 13 having a substantially disk shape having a diameter larger than that of the cylindrical portion 11 is provided at the upper end portion of the cylindrical portion 11, and the connector portion 14 is projected above the flange portion 13. The flange portion 13 is fixed to the transmission case 3 with bolts or the like (not shown). Although not shown, a magnet and a coil are provided inside the cylindrical portion 11.

The base portion 12 has a substantially box shape (rectangular parallelepiped shape) as a whole. That is, the base portion 12 has an upper surface 12a and a lower surface 12b, a front surface 12c and a rear surface 12d, and a left surface 12e and a right surface 12f. The lengths of the base portion 12 in the front-rear direction and the left-right direction are longer than the diameter of the cylindrical portion 11, respectively. Further, the length of the base portion 12 in the front-rear direction is longer than the length in the left-right direction, and the base portion 12 is formed elongated in the front-rear direction. The cylindrical portion 11 penetrates the central portion in the front-rear direction of the upper surface 12a, and its lower end surface is located on the same or substantially the same surface as the lower surface 12b. The length of the base portion 12 in the left-right direction may be equal to the diameter of the cylindrical portion 11. The base portion 12 is made of a non-magnetic material such as resin, and the inside can be formed as a cavity.

As shown in FIG. 3, the movable body 20 is entirely formed in a frame shape by a plurality of plate portions, and a substantially box-shaped accommodation space SP2 is formed inside. That is, the movable body 20 has an upper surface 21a and a lower surface 21b, a front surface 21c and a rear surface 21d, and a left surface 21e and a right surface 21f. The movable body 20 is formed elongated in the front-rear direction corresponding to the base portion 12. The movable body 20 is made of a non-magnetic material such as a resin.

An opening 21g is provided in the central portion of the upper surface 21a of the movable body 20, the cylindrical portion 11 passes through the opening 21g, and the base portion 12 is accommodated in the accommodation space SP2. In the state where the base portion 12 is housed, the faces 21a to 21f of the movable body 20 face each of the faces 12a to 12f of the base portion 12, respectively. The upper surface 12a of the base portion 12 is covered with the upper surface 21a of the movable body 20 at the front end portion and the rear end portion. The remaining surfaces 12b to 12f of the base portion 12 are entirely covered by the surfaces 21b to 21f of the movable body 20, respectively. The lower surface 21b of the movable body 20 constitutes a cover portion that covers the tip end portion of the sensor body 10.

The upper surface 21a and the lower surface 21b of the movable body 20 are formed to be longer in the front-rear direction than the upper surface 12a and the lower surface 12b of the base portion 12. Therefore, the accommodation space SP2 has a gap in the front-rear direction, and the movable body 20 can slide in the front-rear direction with respect to the sensor main body 10. The accommodation space SP2 has no gap or almost no gap in the left-right direction and the vertical direction. The opening 21g is formed so that the front end portion and the rear end portion of the upper surface 12a of the base portion 12 are each covered by the upper surface 21a of the movable body 20 even when the movable body 20 moves to the maximum in the front-rear direction. NS. This makes it possible to prevent the movable body 20 from falling off from the sensor body 10.

A leaf spring 30 (dashed-dotted line) is interposed between the rear surface 21d of the movable body 20 and the rear surface 12d of the base portion 12 in the accommodation space SP2, and the movable body 20 is urged rearward by the leaf spring 30. NS. In the initial state, the movable body 20 is pushed backward by the urging force of the leaf spring 30, but in FIG. 3, the movable body 20 moves forward against the urging force of the leaf spring 30. Shown.

FIG. 4 is a view of the movable body 20 as viewed from the rear (arrow view IV in FIG. 3). As shown in FIGS. 3 and 4, the movable body 20 has a plate-shaped rib portion 22 extending rearward from the upper end portion of the rear surface 21d and extending in the left-right direction, and from the rear surface 21d below the rib portion 22. It has a pair of left and right plate-shaped rib portions 23 projecting rearward. The rib portion 23 extends in the vertical direction, its upper end surface abuts on the lower surface of the rib portion 22, and the lower end surface is located at the same height as the lower surface 21b of the movable body 20. The rib portion 22 and the pair of rib portions 23 form a concave pressure receiving portion 24 surrounded on three sides (upper, left and right sides) on the rear surface 21d of the movable body 20.

Further, the movable body 20 has a pair of left and right plate-shaped rib portions 25 extending downward in the front-rear direction from the lower surface 21b thereof. The pair of rib portions 25 forms a recess 26 open in the front-rear direction on the lower surface 21b of the movable body 20. The rib portion 23 and the rib portion 25 are located at the same position in the left-right direction.

Next, the main operation of the rotation detection device 100 according to the present embodiment will be described. 5A and 5B are diagrams schematically showing an example of the operation of the rotation detection device 100 when the vehicle is stopped and when the vehicle is running, and corresponds to a cross-sectional view of the rotation detection device 100 cut at the center in the left-right direction. do.

As shown in FIG. 5A, when the vehicle is stopped, the movable body 20 is urged rearward by the urging force (arrow F1) of the leaf spring 30. Therefore, the movable body 20 is located at the initial position (also referred to as the first position) that is pushed backward to the maximum. In this state, iron scattered in the accommodation space SP1 (FIG. 1) of the transmission case 3 on the lower surface 21b of the movable body 20 below the lower end central portion 10a (above the axis CL1) of the sensor main body 10 that generates a magnetic force. Foreign matter 8 such as powder may adhere.

As shown in FIG. 5B, when the vehicle is running, the lubricating oil in the accommodation space SP1 is scraped up by the rotation of the differential device 2 and the rotating body 5, and the lubricating oil L1 collides with the rear surface 21d of the movable body 20. As a result, a forward pressing force (arrow F2) acts on the pressure receiving portion 24 of the movable body 20 surrounded by the rib portion 22 and the pair of left and right rib portions 23 below the rib portion 22, and the movable body 20 is a leaf spring. It moves (slides) forward while being guided by the base portion 12 against the urging force of 30. That is, the movable body 20 moves to the second position. As a result, the position of the foreign matter 8 shifts forward from the lower position of the lower end central portion 10a of the sensor main body 10. As a result, the magnetic force acting on the foreign matter 8 is reduced, and the foreign matter 8 can be dropped by the gravity of the foreign matter itself, vibration during traveling, or the like.

At this time, the lubricating oil L2 scraped up by the rotation of the differential device 2 and the rotating body 5 also collides with the lower surface 21b of the movable body 20. That is, the lubricating oil L2 flows from the rear to the front along the recess 26 between the pair of left and right rib portions 25. Due to the flow of the lubricating oil L2, the foreign matter 8 adhering to the lower surface of the movable body 20 due to surface tension or the like can be easily removed. As a result, the accuracy of detecting the vehicle speed by the rotation detection device 100 can be improved. When the rotation of the rotating body 5 is stopped, the movable body 20 returns from the second position to the first position by the urging force of the leaf spring 30.

According to this embodiment, the following effects can be obtained.
(1) The rotation detection device 100 detects the rotation speed of the rotating body 5 arranged inside the transmission case 3 in which the lubricating oil is stored. The rotation detection device 100 is installed with a tip portion separated from the outer peripheral surface (concave and convex portion 5a) of the rotating body 5, and is provided with a sensor body 10 that generates a pulse signal according to a change in magnetic flux accompanying the rotation of the rotating body 5. A direction of FIG. 1, which has a lower surface 21b covering the tip of the sensor body 10 and is perpendicular to the axis CL1 passing through the center of the cylindrical portion 11 of the sensor body 10 and substantially perpendicular to the rotation axis 6 of the rotating body 5. A movable body 20 movably supported by the sensor main body 10 is provided (FIGS. 1 and 3). The movable body 20 further has a pressure receiving portion 24 to which the lubricating oil scraped up by the rotation of the rotating body 5 hits, and is provided so as to move in the A direction (front-back direction) by the oil pressure acting on the pressure receiving portion 24. (Figs. 4 and 5B).

With this configuration, foreign matter 8 such as iron powder adhering to the lower surface 21b of the movable body 20 can be moved forward when the rotating body 5 is rotated, and foreign matter is generated from the lower center portion 10a of the sensor body 10 where magnetic force is generated. The position of 8 shifts. Therefore, the magnetic force acting on the foreign matter 8 is reduced, and the lubricating oil scraped up by the rotation of the rotating body 5 collides with the lower surface 21b of the movable body 20, so that the foreign matter 8 adhering to the lower surface 21b can be easily removed. Can be removed. As a result, the rotation detection accuracy of the rotation detection device 100 is improved. Since the rotation detection device 100 is provided as a whole away from the outer peripheral surface of the rotating body 5, it is possible to prevent a decrease in the durability of the rotation detection device 100.

(2) The rotation detection device 100 further includes a leaf spring 30 that urges the movable body 20 in a direction (rearward) opposite to the direction in which the hydraulic pressure acts (FIG. 3). As a result, the movable body 20 can be moved to the initial position in a state where no oil pressure is applied to the pressure receiving portion 24 of the movable body 20. That is, when the hydraulic pressure acts on the pressure receiving portion 24 of the movable body 20, the movable body 20 moves to the second position, but the movable body 20 can be easily moved to the first position different from the second position. .. Therefore, the foreign matter 8 can be removed with high frequency.

(3) The pressure receiving portion 24 of the movable body 20 has a rear surface 21d on which the hydraulic pressure of the scraped up lubricating oil acts, and rib portions 22 and 23 protruding rearward from the rear surface 21d (FIGS. 3 and 4). .. As a result, the oil pressure acting on the rear surface 21d of the movable body 20 can be increased, and the movable body 20 can be easily moved forward.

(4) The lower surface 21b of the movable body 20 has a pair of left and right rib portions 25 that project toward the outer peripheral surface of the rotating body 5 and extend in the front-rear direction. As a result, a flow path (recess 26) is formed along the lower surface 21b of the movable body 20, the amount of lubricating oil flowing along the lower surface 21b can be increased, and the foreign matter 8 can be easily removed.

The above embodiment can be transformed into various forms. Hereinafter, a modified example will be described. In the above embodiment, the rotation detection device 100 as the rotation detection unit is arranged inside the transmission case 3, but the rotation detection device may be arranged inside another housing in which the lubricating oil is stored. can. In the above embodiment, the permanent magnet is provided inside the sensor main body 10, but instead of this, a sensor main body of a type that generates a magnetic field without having a permanent magnet can be used. In the above embodiment, the sensor main body 10 is formed so as to have the cylindrical portion 11 centered on the axis CL1, but the axis CL1 may pass through the center of the tip portion of the sensor main body, and the sensor main body does not have the cylindrical portion. You may.

In the above embodiment, the sensor main body 10 is provided with the elongated base portion 12 in the front-rear direction, but the elongated base portion 12 may be provided in the left-right direction. In this case, the movable body 20 may be formed elongated in the left-right direction so that the upper surface 21a of the movable body 20 covers the upper surfaces 12a of the left and right end portions of the base portion 12. In the above embodiment, the movable body 20 is configured in a substantially box shape, but the lower surface (cover portion) that covers the tip portion of the sensor body and the pressure receiving portion that is hit by the lubricating oil that is scraped up as the rotating body rotates. Any configuration of the movable body may be used as long as it is provided so as to be movable in a predetermined direction which is substantially perpendicular to the axis passing through the center of the sensor body and substantially perpendicular to the rotation axis of the rotating body.

In the above embodiment, the movable body 20 is provided so as to surround the base portion 12 of the sensor main body 10, and the movable body 20 slides along the upper surface 12a or the like of the base portion 12, but the sliding resistance is reduced. Therefore, for example, a groove portion may be extended in the front-rear direction on the left and right side surfaces 12e and 12f of the base portion 12, and protrusions may be provided on the left and right inner side surfaces of the movable body 20 so as to engage with the groove portion. This eliminates the need for the upper surface 12a of the base portion 12 and the upper surface 21a of the movable body 20 to come into contact with each other.

In the above embodiment, the movable body 20 is moved to the initial position by the leaf spring 30, but another urging member such as a coil spring may be used. Further, for example, the movable body 20 may be moved to the initial position by gravity, and therefore, the urging member that urges the movable body in the direction opposite to the direction in which the hydraulic pressure acts may be omitted. In the above embodiment, the pressure receiving portion 24 is configured by the rear surface 21d (pressure receiving surface) of the movable body 20 and the rib portions 22, 23 (first protruding portions), but the configuration of the pressure receiving portion is not limited to this. In the above embodiment, the rib portion 25 (second protruding portion) is provided on the lower surface 21b of the movable body 20 to form the recess 26, but the configuration of the cover portion is not limited to this.

The above description is merely an example, and the present invention is not limited to the above-described embodiments and modifications as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or a plurality of the above-described embodiments and the modified examples, and it is also possible to combine the modified examples.

3 Transmission case, 5 rotating body, 10 sensor body, 20 movable body, 21b lower surface, 21d rear surface, 22, 23 rib part, 24 pressure receiving part, 25 rib part, 26 concave part, 30 leaf spring, 100 rotation detection device

Claims (4)

A rotation detection device that detects the rotation speed of a rotating body placed inside a housing in which lubricating oil is stored.
A sensor body whose tip is installed away from the peripheral surface of the rotating body and generates a pulse signal according to a change in magnetic flux due to the rotation of the rotating body.
The sensor body has a cover portion that covers the tip portion of the sensor body, and can move in a predetermined direction that is substantially perpendicular to the axis passing through the center of the sensor body and substantially perpendicular to the rotation axis of the rotating body. With a movable body supported by,
The movable body further has a pressure receiving portion to which the lubricating oil scraped up by the rotation of the rotating body hits, and is provided so as to move in the predetermined direction by the hydraulic pressure acting on the pressure receiving portion. Rotation detection device. In the rotation detection device according to claim 1,
A rotation detection device further comprising an urging member that urges the movable body in a direction opposite to the direction in which the hydraulic pressure acts. In the rotation detection device according to claim 1 or 2.
The rotation detecting device is characterized in that the pressure receiving portion has a pressure receiving surface and a first protruding portion that projects substantially vertically from the pressure receiving surface. In the rotation detection device according to any one of claims 1 to 3.
The rotation detecting device, wherein the cover portion has a second protruding portion that protrudes toward the peripheral surface of the rotating body and extends in the predetermined direction.

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