JP6682931B2 - Rotation transmission device with torque measuring device - Google Patents

Description

  The present invention relates to an improvement in a rotation transmission device with a torque measuring device, which is incorporated in, for example, an automatic transmission for automobiles to transmit torque and measure the magnitude of transmitted torque.

  The rotation speed of the shaft that constitutes the automatic transmission for automobiles and the magnitude of the torque transmitted by this shaft are measured, and the measurement result is used as information for performing gear shift control of the transmission or engine output control. It has been used for a long time. As a device that can be used to measure the magnitude of torque, the amount of elastic torsional deformation of the shaft is conventionally converted into a phase difference between the output signals of a pair of sensors, and the torque difference is calculated based on this phase difference. A device for measuring the size is known (see, for example, Patent Documents 1 and 2). Such a conventional structure will be described with reference to FIG.

  In the case of the conventional structure shown in FIG. 4, a pair of encoders 2 and 2 are externally fitted and fixed at two axial positions of a torque transmission shaft 1 that transmits torque during operation. The magnetic characteristics of the surface to be detected, which is the outer peripheral surface of each of the pair of encoders 2 and 2, alternate in the circumferential direction and at equal pitches. Further, the pitches at which the magnetic characteristics of the detected surfaces change in the circumferential direction are the same between the detected surfaces. Further, the pair of sensors 3 and 3 are supported by a housing (not shown) in a state in which the detection portions of the pair of sensors 3 and 3 are opposed to the both surfaces to be detected. The pair of sensors 3 and 3 change their output signals in response to changes in the magnetic characteristics of the portions where their detection units face each other.

  The output signals of the pair of sensors 3 and 3 as described above each cyclically change as the pair of encoders 2 and 2 rotate together with the torque transmission shaft 1. The frequency (and cycle) of this change takes a value commensurate with the rotation speed of the torque transmission shaft 1. Therefore, this rotation speed can be obtained based on this frequency (or cycle). When the torque transmission shaft 1 is elastically twisted and deformed as the torque is transmitted by the torque transmission shaft 1, the pair of encoders 2 and 2 are relatively displaced in the rotational direction. As a result, the phase difference ratio (= phase difference / one cycle) between the output signals of the pair of sensors 3 and 3 changes. The phase difference ratio takes a value commensurate with the torque (the amount of elastic torsional deformation of the torque transmission shaft 1). Therefore, the torque can be obtained based on this phase difference ratio.

  However, in the case of the rotation transmitting device with a torque measuring device having the conventional structure as described above, it is necessary to attach the two sensors 3 and 3 to the housing in a highly accurate relative positional relationship in a state of being separated from each other in the axial direction. There is. For this reason, the work of attaching both of these sensors 3 and 3 becomes troublesome. Moreover, since a total of two harnesses 4 and 4 are required, the wiring work of these harnesses 4 and 4 becomes troublesome (the maneuverability is deteriorated), and the cost and weight are increased.

  In view of such circumstances, the present inventors have completed the rotation transmission device with a torque measuring device described in Patent Document 3 prior to the present invention. The structure of the rotation transmitting device with a torque measuring device according to the prior invention described in Patent Document 3 will be briefly described below with reference to FIG.

  The rotation transmitting device 5 with a torque measuring device according to the previous invention rotatably supports a torque transmitting shaft 6 having a hollow cylindrical shape by a rolling bearing 7 supported and fixed to a housing. Further, the inner shaft 8 is arranged on the inner diameter side of the torque transmission shaft 6, and one end portion of the inner shaft 8 in the axial direction (the right end portion in FIG. 5) cannot rotate relative to the one end portion of the torque transmission shaft 6 in the axial direction. And the other end of the inner shaft 8 in the axial direction (the left end in FIG. 5) is projected from the opening in the other end of the torque transmission shaft 6 in the axial direction to the other side in the axial direction.

  A first encoder 9 is supported and fixed to an inner ring that constitutes the rolling bearing 7, and a second encoder 10 is supported and fixed to the other axial end of the inner shaft 8. The first and second encoders 9 and 10 are composed of support rings (cores) 11 and 12 and permanent magnet encoder bodies 13 and 14 fixed to the outer peripheral surfaces of the support rings 11 and 12, respectively. It is configured. Then, S-poles and N-poles are arranged alternately and at equal pitches in the circumferential direction on the detected surfaces 15 and 16 which are the outer peripheral surfaces of the encoder bodies 13 and 14, respectively. Alternating in the circumferential direction and at equal pitches.

  On the other hand, the sensor unit 17 is supported and fixed to the outer ring forming the rolling bearing 7. The sensor unit 17 is configured by holding a first sensor 19 and a second sensor 20 in a sensor holder 18 made of synthetic resin. The detection portions of the first and second sensors 19 and 20 are provided with magnetic detection elements such as Hall elements, Hall ICs, and MR elements that change the output signal according to the magnetic flux density passing through them. There is. Further, while the sensor unit 17 is supported on the outer ring, the detection portion of the first sensor 19 is opposed to the detection target surface 15 of the first encoder 9 via a small radial gap, The detection portion of the second sensor 20 is opposed to the detection target surface 16 of the second encoder 10 with a small radial gap.

  In the case of the structure described in Patent Document 3, by adopting the above-mentioned configuration, the shaft of the torque transmission shaft 6 is based on the output signals of the first and second sensors 19 and 20. It is possible to determine the magnitude of the torque being transmitted by measuring the relative displacement in the rotational direction between both ends in the direction. Furthermore, since it is possible to arrange the first and second encoders 9 and 10 adjacent to each other in the axial direction by using the inner shaft 8, the first and second sensors 19 and 20 are The sensor holder 18 can be collectively handled while being attached to the sensor holder 18. Therefore, the workability of attaching the sensor can be improved, the wiring work of the harness 4 can be simplified, and the cost and weight can be reduced. Furthermore, since the sensor unit 17 is supported and fixed to the outer ring that constitutes the rolling bearing 7, the detection units of the first and second sensors 19 and 20 and the first and second encoders, respectively. It is also possible to easily and strictly manage the radial gaps between the detected surfaces 15 and 16 of 9 and 10.

However, in the case of the structure described in Patent Document 3 as described above, there is still room for improvement in terms of achieving both improved reliability in torque measurement and downsizing of the entire device.
First, according to the research conducted by the present inventors, detection is performed by a detection unit (magnetic detection element) of a sensor arranged with a minute gap in the radial direction on a surface to be detected (magnetized surface) of an encoder made of a permanent magnet. It was confirmed that the generated magnetic flux density is constant in the widthwise intermediate area of the detected surface, but decreases in the widthwise both end areas toward both edges. The reason for this is that since there is no magnetic flux generation source in the portion of the surface to be detected that is deviated from the widthwise both ends, the number of magnetic fluxes passing through the widthwise both ends decreases toward both edges. It is thought to be for the reason. Therefore, when the encoder is displaced in the axial direction (width dimension of the encoder) with respect to the sensor and the like, the detection portion of the sensor extends from the region in the widthwise middle portion to the regions in the widthwise both ends. The magnetic flux density detected by the detection unit of the sensor may be significantly reduced. Then, in such a case, the output signal of the sensor becomes small and the influence of the jitter becomes large, so that the reliability of the torque measurement using this signal may be lowered.

  From the surface that sufficiently secures the magnetic flux density detected by the detection unit of the sensor, for example, even if the encoder and the sensor are displaced relative to each other in the width direction middle portion of the detected surface of the encoder, this sensor It is conceivable to provide the facing portion where the detecting portion of (1) faces and the non-facing portion where the detecting portion of the sensor does not face even at the time of use at both ends in the width direction. Further, according to the study by the present inventors, the width dimension of the non-opposing portion needs to be about 1.5 mm in order to substantially prevent the decrease of the magnetic flux density detected by the detecting portion of the sensor during use. is there.

  Therefore, with respect to the structure described in Patent Document 3, in order to improve the reliability of torque measurement, each of the detected surfaces 15 and 16 of the first and second encoders 9 and 10 has a width-direction intermediate portion. It is considered to provide a region of the facing portion and two regions of the two non-facing portions at both ends in the width direction. Then, as shown in FIG. 6, the axial dimension L from the first axial edge of the first encoder 9 to the second axial edge of the second encoder 10 is 2 times the axial dimension A of the facing portion 21. The doubled value (2A), the value 4 times the width dimension B of the non-opposing portion 22 {4B (6.0 mm)}, and the gap 23 existing in the portion between the first and second encoders 9 and 10. And the total value of X and {L = 2A + 4B (6.0 mm) + X}. In this way, when it is intended to improve the reliability of torque measurement, the axial dimensions of the first and second encoders 9 and 10 arranged adjacent to each other in the axial direction increase, and the sensor size increases accordingly. The axial dimension of the unit 17 also increases. Therefore, in the case of the structure described in Patent Document 3, it is difficult to improve the reliability of torque measurement and reduce the size of the entire device.

Japanese Patent Laid-Open No. 1-254826 JP-A-63-82330 JP, 2005-172563, A

  In view of the circumstances as described above, the present invention has been devised to realize a structure capable of achieving both improved reliability of torque measurement and miniaturization of the entire device.

The rotation transmission device with a torque measuring device of the present invention includes a torque transmission shaft, an inner shaft, a rolling bearing, a pair of encoders, and a pair of sensors.
Of these, the torque transmission shaft is hollow and transmits torque during use.
The inner shaft is arranged on the inner diameter side of the torque transmission shaft, and the one end portion in the axial direction is relative to the one end portion in the axial direction of the torque transmission shaft (directly or indirectly (via another member)). It is non-rotatably connected and the other end in the axial direction projects from the other end opening in the axial direction of the torque transmission shaft to the other side in the axial direction.
Further, the rolling bearing includes an outer ring, an inner ring, and a plurality of rolling elements, and rotatably supports the torque transmission shaft with respect to a portion that does not rotate during use.
The pair of encoders are made of permanent magnets in which N poles and S poles are alternately arranged in the circumferential direction on each surface to be detected, and are directly connected to the torque transmission shaft or in synchronization with the torque transmission shaft during use. And is supported by a member that rotates.
The pair of sensors have detection units facing the detection surfaces of the pair of encoders and change the output signal according to the magnetic flux density passing through the detection units. Supported by.
The torque transmitted by the torque transmission shaft during use can be measured by using the output signals of the pair of sensors (for example, the phase difference between the output signals, the phase difference ratio).
Further, in the case of the present invention, the pair of encoders (and the pair of sensors) are adjacently arranged (collectively arranged) at one position (the other end in the axial direction) with respect to the axial direction of the torque transmission shaft. are doing.

In particular, in the case of the rotation transmission device with a torque measuring device of the present invention, one of the pair of encoders is fitted with one of the encoders on the other axial end portion of the torque transmission shaft. It is fixed to the inner ring that constitutes it, and the other encoder is fixed to the axially other end side portion of the inner shaft.
The detected surface provided on the axial side surface of the one encoder and the detected surface provided on the axial side surface of the other encoder are the same virtual plane orthogonal to the central axis of the torque transmission shaft. It is placed on top.
Furthermore, the sensor of the pair, constitute one sensor unit by being fixed to one of the sensor holder, a respective detection unit with respect to the detected face of the front Symbol pair of encoders, the torque transmission shaft They are opposed to each other in the axial direction (axial direction).

Further, in the case of carrying out the present invention, the inner shaft is configured in a hollow shape (hollow cylindrical shape, hollow tubular shape) to reduce the weight of the inner shaft and to supply lubricating oil to the internal space of the inner shaft. It can also be used as a flow path.
It is also possible to adopt a configuration in which the outer peripheral surface of the axially intermediate portion of the inner shaft is guided and supported by the inner peripheral surface of the torque transmission shaft. In this case, the outer peripheral surface of the axially intermediate portion of the inner shaft (the surface guided by the inner peripheral surface of the torque transmitting shaft) can be surface-treated to prevent wear. Further, a bush (for example, a slide bearing or a radial needle bearing) can be arranged between the outer peripheral surface of the inner shaft and the inner peripheral surface of the torque transmission shaft.

In a further, from when practicing the present invention, for example, each said pair of encoders, and circular ring-shaped encoder main body made of a permanent magnet, an annular support ring for supporting the encoder body Can be configured.

Further, in the case of implementing the present invention, for example, the pair of sensors is supported inside a sensor cap made of metal, which is supported by a portion that does not rotate during use, through a sensor holder made of synthetic resin. I can do things.
Further, when the present invention is implemented, for example, the sensor cap can be internally fitted and fixed to an axial end portion of the inner peripheral surface of the outer ring that is axially displaced from the outer ring raceway.

  Further, when the present invention is carried out, for example, the surface hardness of the torque transmission shaft may be HV400 or more and the surface carbon concentration may be 0.2% or more.

Further, in the case of carrying out the present invention, the position (formation position, installation position) of the input portion for inputting torque to the torque transmission shaft is not particularly limited, and may be provided at one end portion in the axial direction, It can also be provided at the axially middle portion or at the other axial end. Further, as the input part, for example, a spline part (male spline part or female spline part), a key engagement part, a fitting surface part, and a screw part are directly formed on the outer peripheral surface or the inner peripheral surface of the torque transmission shaft. Besides, the input gear, the input pulley, the input sprocket, and the like may be integrally provided with the torque transmission shaft, or may be separately connected and fixed.
Similarly, the position (formation position, installation position) of the output portion for outputting torque from the torque transmission shaft is not particularly limited, and it may be provided at one end portion in the axial direction, or at the intermediate portion in the axial direction, Alternatively, it may be provided at the other end in the axial direction. Further, as the output part, for example, the spline part (male spline part or female spline part), the key engagement part, the fitting surface part, and the screw part are directly formed on the outer peripheral surface or the inner peripheral surface of the torque transmission shaft. Besides, the output gear, the output pulley, the output sprocket, etc. may be provided integrally with the torque transmission shaft, or may be connected and fixed as a separate body. It is also possible to provide a plurality of output parts on the torque transmission shaft. In this case, for example, a plurality of output gears having different numbers of teeth are provided, or output parts of different types (for example, output pulley and output Gears, etc.) can be provided.

Further, in the case of implementing the present invention, the torque transmission shaft is rotatably provided with one to a plurality of bearings (including at least one rolling bearing) with respect to a portion that does not rotate even when the housing or the like is used. To support. As the bearings used in this case, for example, deep groove type, angular type ball bearings, tapered roller bearings, cylindrical roller bearings, radial needle bearings, self-aligning roller bearings, sliding bearings and the like can be used. When a plurality of bearings are used, for example, of the axially intermediate portion of the torque transmission shaft, the portion between the torque input portion and the torque output portion can be rotatably supported.
Further, when the present invention is implemented, for example, the rotation shaft of the power source for inputting torque to the torque transmission shaft can be arranged coaxially with, parallel to, or perpendicular to the torque transmission shaft.
In this specification, the one end side of the shaft in the axial direction means a portion (including one end part) existing closer to one end in the axial direction than the central part of the shaft, and the other end side in the axial direction on the contrary. Means a portion (including the other end portion) existing closer to the other end in the axial direction than the central portion of the shaft.

According to the rotation transmission device with a torque measuring device of the present invention configured as described above, it is possible to improve the reliability of torque measurement and to reduce the size of the entire device at the same time.
That is, in the case of the present invention, the respective detection portions of the pair of sensors are made to face in the axial direction of the torque transmission shaft with respect to the axial side surfaces of the pair of encoders, which are the surfaces to be detected (magnetized surfaces). ing.
For this reason, in order to improve the reliability of torque measurement, the width of the detected surface of the pair of encoders is determined by providing a facing portion at the widthwise middle portion and non-facing portions at both widthwise end portions. Even if the (radial dimension) is increased, the axial dimension of the pair of encoders need not be increased. Therefore, it is not necessary to increase the axial dimension of the sensor unit including the pair of sensors.
As described above, according to the present invention, the axial dimensions of the pair of encoders and the sensor unit can be determined regardless of the width dimensions of the detection surfaces of the pair of encoders.
Therefore, according to the present invention, the reliability of torque measurement is improved by increasing the width dimension of the surface to be detected, and the overall size of the apparatus is reduced by reducing the axial dimension of the pair of encoders and the sensor unit. It is possible to achieve both.

1 is a sectional view of a rotation transmission device with a torque measuring device, showing an example of an embodiment of the present invention. Similarly, an enlarged view of part A of FIG. FIG. 3 is a view corresponding to FIG. 2, similarly showing a pair of encoder and sensor units removed. The schematic side view which shows the rotation transmission device with a torque measuring device of a conventional structure. FIG. 6 is a schematic cross-sectional view showing another rotation transmitting device with a torque measuring device having a conventional structure. FIG. 6 is a schematic cross-sectional view of a pair of encoder and sensor units shown for explaining the problems of the conventional structure.

[One Example of Embodiment]
An example of an embodiment of the present invention will be described with reference to FIGS. The rotation transmission device 5a with a torque measuring device of this example is used by being incorporated in an automatic transmission for an automobile, for example. Such a torque transmitting device-equipped rotation transmitting device 5a includes a housing (mission case) 24, a hollow (hollow cylindrical) torque transmitting shaft 6a that functions as an input shaft (or counter shaft) of a belt type CVT, and the like. It is provided with a pair of rolling bearings 7a and 7b, an input gear 25, an output gear 26, an inner shaft 8a, a first encoder 9a, a second encoder 10a, and one sensor unit 17a.

  The torque transmission shaft 6a is made of an alloy steel such as carbon steel in a hollow cylindrical shape, and is subjected to heat treatment such as quenching and tempering so that the surface hardness of the torque transmission shaft 6a is HV400 or more. At the same time, the surface carbon concentration is set to 0.2% or more. Further, in the case of this example, the input gear 25 for inputting the torque to the torque transmission shaft 6a is provided at the axially intermediate portion of the torque transmission shaft 6a and separately from the torque transmission shaft 6a. The output gear 26 for outputting torque is provided separately from the torque transmission shaft 6a at a portion of the torque transmission shaft 6a near the one end in the axial direction (a portion near the right end in FIG. 1). Further, of the torque transmission shaft 6a, both side portions (the other end portion in the axial direction and the one end portion in the axial direction) sandwiching the portion where the input gear 25 and the output gear 26 are installed are connected to the pair of rolling bearings 7a. , 7b rotatably support the housing 24.

  The input gear 25 and the output gear 26 are helical gears or spur gears made of alloy steel such as carbon steel, and are provided separately from the torque transmission shaft 6a. Therefore, with respect to the fitting portions of the input gear 25 and the output gear 26, a cylindrical surface fitting portion for ensuring concentricity and an involute spline engagement portion for preventing relative rotation are provided in the axial direction. Adopted a configuration that is adjacent to.

  The pair of rolling bearings 7a and 7b are, for example, deep groove type, angular type ball bearings, tapered roller bearings, cylindrical roller bearings, radial needle bearings, self-aligning roller bearings, etc. (illustrated examples are ball bearings). Each of them is composed of an outer ring 27a, 27b and an inner ring 28a, 28b, which are annular, and a plurality of rolling elements (balls) 29a, 29b. Outer rings 27a and 27b are stationary wheels that do not rotate even during use, and are fitted and fixed to the housing 24. The inner rings 28a, 28b are rotating wheels that rotate during use, and are fitted and fixed to the torque transmission shaft 6a. Each of the rolling elements 29a, 29b is between an outer ring raceway formed on an inner peripheral surface of an axial intermediate portion of the outer races 27a, 27b and an inner raceway formed on an outer peripheral surface of an axial intermediate portion of the inner rings 28a, 28b. In the state where it is held by the cage, it is rotatably provided. Further, in the case of this example, the contact angles of the pair of rolling bearings 7a and 7b are opposite to each other.

  The inner shaft 8a is made of an alloy steel such as carbon steel or a synthetic resin into a substantially columnar shape (or a cylindrical shape), and is arranged on the inner diameter side of the torque transmission shaft 6a and concentrically with the torque transmission shaft 6a. Has been done. Further, the inner shaft 8a has one axial end (the right end in FIG. 1) connected to the one axial end of the torque transmission shaft 6a such that the inner shaft 8a cannot rotate relative to the other end (see FIG. 1). (The left end portion) of the torque transmission shaft 6a is projected from the other end opening in the axial direction of the torque transmission shaft 6a to the other side in the axial direction. In the case of the structure shown in the figure, in order to connect the one axial end of the inner shaft 8a to the one axial end of the torque transmission shaft 6a such that the inner shaft 8a cannot rotate relative to the one axial end, the axial end of the inner shaft 8a is provided. The outer peripheral surface of the large-diameter portion 30 and the inner peripheral surface of one end of the torque transmission shaft 6a in the axial direction are fitted and fixed by interference fit so as not to rotate relative to each other. It should be noted that in order to connect the two circumferential surfaces to each other so that they cannot rotate relative to each other, engagement by an involute spline or a key may be adopted. Further, in the case of this example, a gap (a minute gap) is formed between the outer peripheral surface of the inner shaft 8a which is axially displaced from the large diameter portion 30 and the inner peripheral surface of the torque transmission shaft 6a. ) Is provided. It is also possible to fill the part between these with lubricating oil and to function as a film damper.

  The first encoder 9a is supported and fixed to the inner ring 28a that constitutes the rolling bearing 7a. In other words, the first encoder 9a is indirectly attached to the other axial end of the torque transmission shaft 6a via the inner ring 28a that constitutes the rolling bearing 7a. Therefore, the first encoder 9a can rotate (synchronously) with the other axial end of the torque transmission shaft 6a. On the other hand, the second encoder 10a is externally fitted to a portion of the inner shaft 8a that protrudes from the other end in the axial direction of the torque transmission shaft 6a to the other side in the axial direction (the other end in the axial direction). It is fixed. In other words, the second encoder 10a is indirectly attached to the one axial end of the torque transmission shaft 6a via the inner shaft 8a. Therefore, the second encoder 10a can rotate (synchronously) with the one axial end of the torque transmission shaft 6a.

  Particularly in the case of this example, the first encoder 9a is composed of a support ring (core bar) 31 made of a metal plate and an encoder body 32 made of a permanent magnet such as a rubber magnet or a plastic magnet. Of these, the support ring 31 has an inverted L-shaped cross section and is formed in an annular shape as a whole. The support ring 31 is externally fitted and fixed to the shoulder portion of the inner ring 28a constituting the rolling bearing 7a on the other end side in the axial direction. The cylindrical portion 33 and the circular ring portion 34 that is bent at a right angle inward in the radial direction from the other end in the axial direction of the fitting cylindrical portion 33 are provided. Further, the encoder body 32 is formed into a circular ring plate shape by dispersing magnetic powder in a polymer material such as rubber or synthetic resin, and fixing means such as adhesion to the other side surface of the circular ring portion 34 in the axial direction. It is supported and fixed by. In the case of this example, the other side surface in the axial direction of the encoder body 32 is the detected surface (magnetized surface) 35.

On the other hand, the second encoder 10a includes a support ring (core bar) 36 made of a metal plate and an encoder body 37 made of a permanent magnet such as a rubber magnet or a plastic magnet. Of these, the support ring 36 has an L-shaped cross section and is configured in an annular shape as a whole, and has a fitting cylinder portion 38 fitted and fixed to the other axial end of the inner shaft 8a, and the fitting cylinder. A circular ring portion 39 that is bent at a right angle outward in the radial direction from the other end of the portion 38 in the axial direction is provided. Further, the encoder body 37 is formed into an annular plate shape by dispersing magnetic powder in a polymer material such as rubber or synthetic resin, and fixing means such as adhesion to the other side surface of the annular portion 39 in the axial direction. It is supported and fixed by. Further, in the case of this example, the other side surface in the axial direction of the encoder body 37 is a surface to be detected (magnetized surface) 40.
The magnetic powder contained in the encoder bodies 32 and 37 is, for example, ferrite-based magnetic powder such as strontium ferrite and barium ferrite, and rare earth elements such as samarium-iron, samarium-cobalt and neodymium-iron-boron. Magnetic powder can be used.

  In addition, in the case of the present example, the first encoder 9a is externally fitted and fixed to the shoulder portion on the other axial end side of the inner ring 28a that constitutes the rolling bearing 7a, and the second encoder 10a is The first encoder 9a and the second encoder 10a are arranged so as to overlap with each other in the radial direction but not to overlap with each other in the radial direction while being externally fitted and fixed to the other end of the shaft 8a in the axial direction. ing. Therefore, the inner diameter of the first encoder 9a located on the outer diameter side is larger than the outer diameter of the second encoder 10a located on the inner diameter side. The detected surface 35 of the first encoder 9a and the detected surface 40 of the second encoder 10a are concentric with each other and are adjacent to each other in the radial direction (for example, within 10 mm in the radial direction, Preferably, they are arranged at intervals of 5 mm or less) and are located on the same virtual plane orthogonal to the central axis of the torque transmission shaft 6a.

  In addition, S poles and N poles are arranged alternately and at equal pitches in the circumferential direction on the detected surfaces 35 and 40, respectively, and the magnetic characteristics are alternately and equally pitched in the circumferential direction. It is changing. Further, the pitches (center angle pitches) at which the magnetic characteristics of the detected surfaces 35, 40 change in the circumferential direction are the same between the detected surfaces 35, 40. Therefore, the total number of magnetic poles (S poles, N poles) of both the detected surfaces 35, 40 is equal to each other. The first encoder (encoder body) may be directly attached to the inner ring without the support ring. In addition, a female screw is formed on the inner peripheral surface of the support ring that constitutes the second encoder, and this female screw is screwed into a male screw portion formed at the other axial end of the inner shaft, whereby the second encoder is It may be attached to the other axial end of the shaft.

  Further, in the case of this example, the sensor unit 17a is supported and fixed to the outer ring 27a that constitutes the rolling bearing 7a. The sensor unit 17a includes the first sensor 19a, the second sensor 20a, the sensor holder 18a, and the sensor cap 41. Of these, the first and second sensors 19a and 20a output signals according to the magnetic flux density passing through themselves, such as Hall element, Hall IC, MR element (including GMR element, TMR element, and AMR element). The detectors 42a and 42b are provided with magnetic detecting elements that change the magnetic field.

  Further, the sensor holder 18a is made of synthetic resin and is formed in a disc shape as a whole. The respective members 19a, 20a, 18a are arranged inside the sensor cap 41 with the first and second sensors 19a, 20a attached to the sensor holder 18a. . In the case of the present example, an annular recess 43 is formed on one side surface in the axial direction of the sensor holder 18a, and the first sensor is provided at one position in the circumferential direction of the outer diameter side half of the annular recess 43. 19a is arranged, and the second sensor 20a is arranged at one position in the circumferential direction of the inner diameter side half portion of the annular recess 43 (a portion out of phase with the installation position of the first sensor 19a). are doing. As a result, the first and second sensors 19a and 20a are in a state of overlapping in the radial direction.

  The sensor cap 41 is configured by combining (fitting) a pair of cap elements 44a and 44b with each other in the axial direction. Each of the pair of cap elements 44a and 44b is made by pressing a rolled steel plate such as SPCC having a plate thickness of about 0.5 to 1.3 mm.

  Of the pair of caps 44a, 44b, one cap element 44a is configured to have a substantially U-shaped cross section, and has a circular bottom portion 45, and an outer diameter side end portion of the bottom portion 45 extending from the one end in the axial direction to the one end side. The outer cylindrical portion 46 is provided so as to be bent at a right angle toward the outer cylindrical portion 46. Further, at one position in the circumferential direction of the bottom portion 45, there is provided a harness drawing hole for drawing out a harness (not shown).

  On the other hand, of the pair of cap elements 44a, 44b, the other cap element 44b projects radially inward from the inner cylindrical portion 47 and the inner peripheral surface of the axially intermediate portion of the inner cylindrical portion 47. And a ring-shaped holding plate portion 48 provided in Step 1. Further, in the case of this example, in the free state, the outer diameter dimension of the inner tubular portion 47 is set to be slightly larger than the inner diameter dimension of the outer tubular portion 46 constituting the one cap element 44a.

  Then, in the case of the present example, the other half in the axial direction of the inner tubular portion 47 that constitutes the other cap element 44b is press-fitted into the outer tubular portion 46 that constitutes the one cap element 44a (internally by tight fitting). By fitting and fixing), the one cap element 44a and the other cap element 44b are axially combined to form the sensor cap 41. Further, in this way, in the state where the pair of cap elements 44a and 44b are combined, the radially outer end portion of the sensor holder 18a is made to correspond to the outer diameter side end portion of the bottom portion 45 of the one cap element 44a. , Between the other cap element 44b and the holding plate portion 48 from both sides in the axial direction. Also, the harness is pulled out to the other side in the axial direction through a harness pull-out hole formed in a part of the bottom portion 45.

  Further, in the case of this example, the sensor cap 41 having the above-mentioned configuration is supported and fixed to the outer ring 27a which constitutes the rolling bearing 7a. Therefore, in the inner peripheral surface of the outer ring 27a, the inner diameter dimension is large at the other axial end portion of the shoulder portion 50 provided on the other axial side of the outer ring raceway 49 formed at the central portion in the axial direction. The mating stepped portion 51 is formed. Then, with respect to the fitting step portion 51, of the other cap element 44b constituting the sensor cap 41, the axial one side half portion of the inner cylindrical portion 47 has a press-fitting tightening margin of, for example, about 20 to 400 μm. It is press-fitted and fixed within the range. This prevents the sensor cap 41 from falling off and prevents damage at the time of press fitting. Further, the rolling element 29a constituting the rolling bearing 7a is prevented from riding on the shoulder portion 50 while keeping the inner diameter of a portion of the shoulder portion 50 axially adjacent to the outer ring raceway 49 small. are doing.

  Further, in the case of the present example, in a state where the sensor cap 41 is press-fitted and fixed to the fitting stepped portion 51 of the outer ring 27a, the detection portion 42a constituting the first sensor 19a installed inside the The detection part 42b constituting the second sensor 20a is made to face the detection surface 35 of the first encoder 9a via a minute gap in the axial direction, and the detection portion 42b of the second encoder 10a is detected. On the other hand, they are opposed to each other via a minute gap in the axial direction. Therefore, the first sensor 19a changes the output signal in response to the change in the magnetic characteristic of the first encoder 9a, and the second sensor 20a changes the change in the magnetic characteristic of the second encoder 10a. The output signal is changed correspondingly. Then, the respective output signals of the first and second sensors 19a and 20a are transmitted to a computing unit (not shown) through one harness pulled out in the axial direction. In addition, electric power is supplied to the first and second sensors 19a and 20a through this harness.

  Also in the case of the torque transmitting device with torque measuring device 5a having the above-mentioned configuration, the output signals of the first and second sensors 19a and 20a constituting the sensor unit 17a are the same as those of the torque transmitting device. As the first and second encoders 9a and 10a rotate together with the shaft 6a, they cyclically change. Here, the frequency (and cycle) of this change takes a value commensurate with the rotation speed of the torque transmission shaft 6a. Therefore, if the relationship between the frequency (or cycle) and the rotation speed is checked in advance, this rotation speed can be obtained based on this frequency (or cycle). Further, when torque is transmitted by the torque transmission shaft 6a, both ends in the axial direction of the torque transmission shaft 6a are elastically twisted and deformed between the input gear 25 and the output gear 26. The two (first and second two encoders 9a, 10a) are relatively displaced in the rotation direction. Then, as a result of the relative displacement of the first and second encoders 9a and 10a in the rotational direction in this way, the phase difference ratio (= phase difference) between the output signals of the first and second sensors 19a and 20a. / 1 cycle) changes. Here, this phase difference ratio takes a value commensurate with the torque. Therefore, if the relationship between the phase difference ratio and the torque is investigated in advance, the torque can be calculated based on the phase difference ratio. The calculation processing is performed by the arithmetic unit. For this reason, the relationship between the phase difference ratio and the torque, which has been investigated by theoretical calculation or experiment in advance, is incorporated in this computing unit by a formula such as a calculation formula or a map.

In particular, according to the rotation transmission device 5a with a torque measuring device of the present example, it is possible to improve the reliability of torque measurement and to reduce the size of the entire device.
That is, in the case of the present example, the detection portions 42a and 42b of the first and second sensors 19a and 20a are respectively detected on the other side surfaces in the axial direction of the first and second encoders 9a and 10a. The surfaces 35 and 40 are axially opposed to each other.
Therefore, for the purpose of ensuring the reliability of torque measurement, the detected surface 35 of the first encoder 9a and the detected surface 40 of the second encoder 10a are, for example, as shown in FIG. The width dimension (radial dimension) of each of the detected surfaces 35, 40 is increased by, for example, providing the facing portion 21 in the widthwise (radial direction) middle portion and the non-facing portion 22 at both ends in the widthwise (radial direction). Also in this case, the axial dimensions of the first and second encoders 9a and 10a need not be increased. Therefore, the axial size of the sensor unit 17a including the first and second sensors 19a and 20a need not be increased.
As described above, according to the structure of the present example, regardless of the width dimension (radial dimension) of the detected surface 35 of the first encoder 9a and the detected surface 40 of the second encoder 10a, the first, The axial dimension of the second encoders 9a and 10a can be determined, and the axial dimension of the sensor unit 17a can be determined. Therefore, in the case of the present example, it is possible to improve the reliability of torque measurement by securing large width dimensions of the detected surface 35 of the first encoder 9a and the detected surface 40 of the second encoder 10a, respectively. It is possible to achieve both miniaturization of the entire apparatus by reducing the axial dimensions of the first and second encoders 9a and 10a and the sensor unit 17a. Particularly, in the case of this example, the first and second encoders 9a and 10a each having an annular shape (annular shape) are arranged in a state of overlapping in the radial direction, and the first and second sensors 19a, 19a, Since 20a is arranged in a state of overlapping in the radial direction, the axial dimensions of the first and second encoders 9a and 10a and the sensor unit 17a can be made sufficiently small.

  Further, in the case of this example, since the sensor cap 41 supporting the first and second sensors 19a and 20a is supported and fixed to the outer ring 27a which constitutes the rolling bearing 7a, the rolling bearing 7a It is possible to easily position the first sensor 19a with respect to the first encoder 9a that is supported and fixed to the inner ring 28a that constitutes the rolling bearing 7a. Therefore, the positional relationship between the first encoder 9a and the first sensor 19a can be easily and strictly regulated. Further, in the case of the present example, even with respect to the second sensor 20a, the rolling bearing 7a can be used for positioning. Therefore, the detection portions 42a and 42b of the first and second sensors 19a and 20a and the detected surfaces 35 of the first and second encoders 9a and 10a (particularly the first encoder 9a supported by the inner ring), It becomes possible to easily and strictly manage the axial gap with respect to 40 (axial gap).

  Further, in the case of the present example, since the harness is pulled out in the axial direction, when the rolling bearing 7a having the sensor unit 17a mounted therein is fixedly fitted in the housing 24, the harness does not interfere. It is possible to prevent the installation workability from being deteriorated.

  Further, since the first encoder 9a is attached to the inner ring 28a that constitutes the rolling bearing 7a, which is smaller in size and lighter in weight than the torque transmission shaft 6a, the first encoder 9a is As compared with the case where the first encoder 9a is directly attached to the torque transmission shaft 6a, the workability of attaching the first encoder 9a can be improved. Further, in the case of this example, the surface hardness of the torque transmission shaft 6a is set to HV400 or more and the surface carbon concentration is set to 0.2% or more, so that the durability of the torque transmission shaft 6a can be improved. . Therefore, the rotation transmission device 5a with a torque measuring device according to the present embodiment can be preferably applied to applications such as automobiles and wind power generators, which require particularly durability. Moreover, in the case of this example, since the torque transmission shaft 6a is rotatably supported by the pair of rolling bearings 7a and 7b, the torque transmission shaft 6a can be compared with the case where the configuration in which it is supported by the slide bearing is adopted. The friction torque acting on the transmission shaft 6a can be suppressed to be small. For this reason, a large torque can be secured by the torque transmission shaft 6a, and the torque measurement accuracy obtained from the output signals of the first and second sensors 19a and 20a can be improved.

  The torque transmission shaft that constitutes the rotation transmission device with the torque measuring device according to the present invention is not limited to the rotation shaft that constitutes the power train of an automobile, but may be, for example, a rotation shaft of a wind turbine (main shaft, rotation shaft of a speed increaser), a rolling mill. Roll neck, rotating shafts of railway vehicles (axles, rotating shafts of speed reducers), rotating shafts of machine tools (main shafts, rotating shafts of feed systems), construction machinery / agricultural machinery / household appliances / motor rotating shafts, etc. It is possible to target the rotating shafts of various mechanical devices. Further, when configuring a power train of an automobile, for example, an input shaft (turbine shaft) to which torque is input from a torque converter or a counter shaft can be targeted. Further, the type of the transmission in the case where the rotation transmitting device with the torque measuring device of the present invention is incorporated to form the transmission is not particularly limited, and various continuously variable transmissions such as an automatic transmission (AT), a belt type and a toroidal type are used. A transmission such as a machine (CVT), an automated manual transmission (AMT), a dual clutch transmission (DCT), a transfer, etc., which shifts by vehicle-side control can be adopted. Further, the relationship between the installation position of the transmission and the drive wheels is not particularly limited, and a front engine front wheel drive vehicle (FF vehicle), a front engine rear wheel drive vehicle (FR vehicle), a four wheel drive vehicle, etc. may be used. Be the target. Further, the measured rotation speed and torque may be used to perform vehicle control other than shift control and engine output control. Further, the power source placed on the upstream side of the transmission does not necessarily have to be an internal combustion engine such as a gasoline engine or a diesel engine, but may be an electric motor used in a hybrid vehicle or an electric vehicle, for example. Further, when the present invention is carried out, it is essential to measure the torque, but it is not essential to measure the rotation speed. Even if the rotation speed is required, it can be measured separately with a simple structure.

  Further, in the above-mentioned embodiment, the structure in which the support ring forming the first encoder is supported by the inner ring forming the rolling bearing has been described as an example, but it is directly supported on the outer peripheral surface of the other end in the axial direction of the torque transmission shaft. You may employ | adopt the structure (it fits outside and fixes). Similarly, the sensor cap may be supported and fixed to the housing instead of the outer ring forming the rolling bearing. Further, in each example of the embodiments, the case where the ball bearing is used as the rolling bearing for rotatably supporting the torque transmission shaft has been described, but in the case of carrying out the present invention, the deep groove ball bearing, Rolling bearings having various conventionally known structures such as tapered roller bearings, needle bearings, cylindrical roller bearings and angular ball bearings can be used.

1 torque transmission shaft 2 encoder 3 sensor 4 harness 5, 5a rotation transmission device with torque measuring device 6, 6a torque transmission shaft 7, 7a, 7b rolling bearing 8, 8a inner shaft 9, 9a first encoder 10, 10a second Encoder 11 Support ring 12 Support ring 13 Encoder main body 14 Encoder main body 15 Detected surface 16 Detected surface 17, 17a Sensor unit 18, 18a Sensor holder 19, 19a First sensor 20, 20a Second sensor 21 Facing part 22 Non-opposed part 23 Gap 24 Housing 25 Input gear 26 Output gear 27a, 27b Outer ring 28a, 28b Inner ring 29a, 29b Rolling body 30 Large diameter part 31 Support ring 32 Encoder main body 33 Fitting cylinder part 34 Circle ring part 35 Detected surface 36 Support ring 37 Encoder main body 38 Fitting cylinder portion 39 Circle ring portion 4 The detected surface 41 sensor cap 42a, 42b detecting unit 43 annular recess 44a, 44b cap element 45 bottom 46 outer tubular portion 47 inner tubular portion 48 sandwiching plate portion 49 outer raceway 50 shoulder 51 engaging the stepped portion

Claims (1)

A hollow torque transmission shaft that transmits torque when in use,
It is arranged on the inner diameter side of the torque transmission shaft, one end portion in the axial direction is connected to the one end portion in the axial direction of the torque transmission shaft in a non-rotatable manner, and the other end portion in the axial direction is in the axial direction of the torque transmission shaft. An inner shaft protruding from the end opening to the other side in the axial direction,
To the portion which does not rotate during use the torque transmission shaft, a rolling bearing for rotatably supporting,
Each surface to be detected is made of a permanent magnet having S poles and N poles alternately arranged in the circumferential direction, and is supported directly on the torque transmission shaft or by a member that rotates in synchronization with the torque transmission shaft during use. A pair of encoders,
A pair of sensors supported by portions that do not rotate even when in use, in which respective detection portions are opposed to the detection surfaces of the pair of encoders, and an output signal is changed according to the magnetic flux density passing through the detection portions; ,,
The pair of encoders are arranged adjacent to each other in the axial direction of the torque transmission shaft.
A rotation transmission device with a torque measuring device,
Of the pair of encoders, one encoder is fixed to an inner ring that constitutes the rolling bearing and is externally fitted to the axially other end side portion of the torque transmission shaft, and the other encoder is the inner ring. It is fixed to the other end of the shaft in the axial direction,
The detected surface provided on the axial side surface of the one encoder and the detected surface provided on the axial side surface of the other encoder are on the same virtual plane orthogonal to the central axis of the torque transmission shaft. Has been placed,
Sensor of the pair is fixed to one of the sensor holder, constitutes the one sensor unit, each of the detector with respect to the detected face of the front Symbol pair of encoders, the axis of the torque transmission shaft Facing each other,
A rotation transmission device with a torque measurement device.

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