JP2006194360A - Constant velocity universal joint device with torque detecting function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity universal joint device with torque detecting function for measuring torque which operates on each wheel of a FF vehicle or a 4WD vehicle and easily securing an installation site of a measuring means. <P>SOLUTION: The device comprises a constant velocity universal joint 2 on the outboard side connected to a wheel bearing 31, a constant velocity universal joint 3 on the inboard side fixed to the side of a differential 8, and a drive shaft 4 connected at both ends to single-side joint members 9, 11 of both constant velocity universal joints 2, 3. A distortion detecting means 5 is provided for detecting distortion due to torque operating on the drive shaft 4. The distortion detecting means 5 has a detected part 6 formed of a magnetically distortional material and a detecting part 7 opposed thereto. The detecting part 7 is installed on the outer ring of a bearing 13 whose inner ring is mounted on the drive shaft 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a constant velocity universal joint device having a function of detecting torque applied to a drive shaft of a wheel.

2. Description of the Related Art Conventionally, as part of measures for ensuring driving stability of an automobile, a technique has been proposed in which an actual torque transmitted by an automobile drive system is detected by a torque detector. As an example, in a drive system connected to a propeller shaft from a transmission output shaft through a constant velocity universal joint, torque transmitted from the output shaft to the propeller shaft is detected by a torque detection device ( For example, Patent Document 1). The torque detection device in this case includes a magnetostrictive ring fixed to the outer peripheral surface of the constant velocity universal joint connected to the transmission output shaft, and a magnetic sensor provided in a non-contact manner facing the outer periphery of the magnetostrictive ring. Consists of. The magnetic sensor is provided on an inner diameter surface of a sensor housing provided on a shaft portion of the constant velocity universal joint via a bearing. The sensor housing is covered with a dust cover fixed to the transmission case, and the sensor housing is connected to the dust cover via a bracket.
JP 2004-239822 A

However, many passenger car-type automobiles in recent years are FF cars (front engine / front drive), and do not have a propeller shaft as disclosed in Patent Document 1. In addition, conventional measures for ensuring driving safety in general automobiles are not sufficient to detect the driving torque output from the transmission, but also to detect the driving torque output from the differential to each wheel. For example, it is required to control the attitude of the vehicle body.
Further, most of the structures of the output system from the differential of the FF vehicle are such that the stem portion of the constant velocity universal joint is fitted to the side gear of the differential, and the torque detection device disclosed in Patent Document 1 is attached to this stem portion. It is difficult to obtain a space for mounting.

  An object of the present invention is to provide a constant velocity universal joint device with a torque detection function that can measure torque acting on each wheel and can easily secure an installation place of a means for detecting torque.

  The constant velocity universal joint device with a torque detection function of the present invention includes an outboard side constant velocity universal joint arranged on a wheel side of an automobile, an inboard side constant velocity universal joint fixed to a differential side, In a constant velocity universal joint device having a drive shaft connected at both ends to one joint member of the outboard side constant velocity universal joint and one joint member of the inboard side constant velocity universal joint, the constant velocity universal joint device acts on the drive shaft. Distortion detecting means for detecting the distortion of the drive shaft due to torque is provided.

  According to this configuration, the torque acting on the wheels acts on the drive shaft between the constant velocity universal joints on the outboard and inboard sides. Distortion due to torque acting on the drive shaft is detected by the strain detection means. Therefore, the torque acting on each wheel can be measured. Since the torque acting on each wheel is detected, it is suitable for torque detection in a vehicle that does not have a propeller shaft such as an FF vehicle, a 4WD vehicle (four-wheel drive vehicle), and the like. Since the strain detection means detects torque acting on the drive shaft, it can be installed in a wide space around the drive shaft, and the installation location can be easily obtained. Since the drive shaft is a long component in the drive transmission system, distortion due to torque is greater than that of other components. For this reason, torque detection by strain detection can be performed relatively easily and accurately.

  For example, the strain detecting means may include a detected part provided on the drive shaft and a detecting part provided on a fixed part fixed to the vehicle body to detect a change in the detected part. . In this case, since the detection unit is installed in the fixed unit, a wiring system for taking out the detection signal becomes easy.

In the present invention, a serration portion is provided on a part of the drive shaft, a detected portion comprising a magnetostrictive portion having a serration portion press-fitted into the serration portion on the inner diameter surface is provided, and the drive is parallel to the detected portion. A bearing in which an inner ring is fitted to the shaft is arranged, a detection unit that detects a change in magnetostriction of the detected portion is provided in an inner diameter part of the outer ring of the bearing, and the outer ring of the bearing is attached to a fixed part fixed to the vehicle body. It may be fixed via an elastic body to prevent the outer ring from rotating, and the strain detection means may be constituted by the serration portion, the detected portion, the bearing, the detection portion, and the elastic body.
If the detected portion of the strain detecting means is a magnetostrictive portion, the strain can be easily detected with high accuracy. In this case, it is possible to provide the magnetostriction portion directly on the drive shaft, but providing the magnetostriction portion on the drive shaft which is a large component is not productive. Therefore, as described above, the drive shaft is provided with only a serration portion, and the serration portion is provided with a detected portion made of a magnetostriction portion, and the detected portion can be made up of small parts, thereby improving productivity. Since the detection unit is attached to the outer ring of the bearing with the inner ring fitted to the drive shaft, the detection unit should be stably placed near the detected part press-fitted to the drive wheel and detected accurately. Can do. Since the outer ring of the bearing is fixed to the fixed part via the elastic body in a non-rotating state, an unreasonable load is applied to the drive shaft when the outer ring is locked and rotation failure occurs in the bearing. To be absorbed by the elastic body.

  When the bearing for attaching the detection unit is provided as described above, a seal member may be provided between the outer ring of the bearing and the drive shaft. By attaching the seal member in this way, foreign matter can be prevented from entering the space between the drive shaft where the detected part and the detecting part, which are components of the strain detecting means, and the bearing outer ring are arranged. it can.

  In the present invention, the detection unit may be a coil. A detection unit wound with a coil is excellent in detection accuracy. In particular, when the detected portion is a magnetostrictive portion, an excellent detection function can be obtained if the detecting portion is a coil.

  The detected part may have a plurality of grooves on the outer diameter, and the grooves may be inclined with respect to the axis. In the case where the detected part having the inclined groove is provided, the detection sensitivity can be increased. In particular, when the detected part is a magnetostrictive material, the structure having the inclined groove improves the magnetostrictive characteristics of the detected part and improves the detection sensitivity.

  As described above, when the serration part is provided in the detected part, the serration part of the detected part may have a structure in which the serration part is left at both ends and the central part is deleted. In this configuration, the detected portion can be stably coupled to the drive shaft, and distortion due to torque acting on the drive shaft can be reliably reflected on the detected portion.

  In the present invention, the detected portion may be a metal surface on which aluminum is diffused in a metal base material to form an alloy layer on the surface. In the case of this configuration, excellent magnetostriction characteristics can be obtained in the detected part, and the detected part can be provided with sufficient mechanical strength and can be provided with workability suitable for mass production.

The detected part may be one using a clad steel of an Fe—Al alloy, or one using a bulk material.
An Fe—Al alloy is excellent in magnetostriction, and when it is a clad steel, it is strong in strength and has a strong bonding strength with a base material made of carbon steel. In addition, since the magnetostrictive characteristics are excellent, an improvement in sensitivity can be expected.

  In the present invention, the elastic body that supports the outer ring may be supported in a direction perpendicular to the vertical movement of the wheel in the forward or backward direction of the vehicle. In the case of this configuration, the expansion / contraction stroke of the elastic body accompanying the vertical movement of the wheel can be reduced, and the durability is improved.

  The constant velocity universal joint device with a torque detection function of the present invention includes an outboard side constant velocity universal joint arranged on a wheel side of an automobile, an inboard side constant velocity universal joint fixed to a differential side, In a constant velocity universal joint device having a drive shaft connected at both ends to one joint member of the outboard side constant velocity universal joint and one joint member of the inboard side constant velocity universal joint, the constant velocity universal joint device acts on the drive shaft. Since the strain detecting means for detecting the distortion of the drive shaft due to the torque is provided, there is an advantage that the torque acting on each wheel can be measured and the installation place of the means for detecting the torque can be easily secured.

  An embodiment of the present invention will be described with reference to FIGS. The constant velocity universal joint device 1 with a torque detection function is provided between a wheel of an automobile such as an FF vehicle or a 4WD vehicle and the differential 8. As shown in a horizontal sectional view in FIG. 1, the constant velocity universal joint 2 on the outboard side arranged on the wheel bearing 31 side, the constant velocity universal joint 3 on the inboard side fixed to the differential 8 side, A drive shaft 4 having both ends connected to the constant velocity universal joints 2 and 3 and a strain detection means 5 for detecting the strain of the drive shaft 4 due to torque acting on the drive shaft 4 are provided. One end of the drive shaft 4 is connected to a joint inner ring 9 which is one joint member of the outboard side constant velocity universal joint 2, and the other end is connected to a joint inner ring 11 which is one joint member of the inboard side constant velocity universal joint 3. Each is connected. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  A joint outer ring 10 which is the other joint member of the outboard side constant velocity universal joint 2 is connected to a hub ring 35 which is a component part of the inner member 33 of the wheel bearing 31 at its stem portion 10a. A joint outer ring 12 which is the other joint member of the inboard side constant velocity universal joint 3 is connected to a side gear (not shown) of the differential 8 at its stem portion (not shown).

  The wheel bearing 31 is, for example, a third generation type, and includes an outer member 32 having a double-row raceway surface on the inner periphery, and an inner member having a raceway surface facing each raceway surface of the outer member 32. 33 and double row rolling elements 34 interposed between both raceway surfaces of the outer member 32 and the inner member 33. A flange 32 a that is attached to a knuckle or the like in a vehicle suspension system (not shown) is provided on the outer periphery of the outer member 32. The inner member 33 includes a hub wheel 35 having a wheel mounting flange 35 a at the outboard side end, and an inner ring 36 fitted to the outer periphery of the inboard side end of the hub wheel 35. The joint outer ring stem portion 10a of the outboard-side constant velocity universal joint 2 is inserted into the central hole 36 of the hub wheel 35, and the nut 37 is tightened on the male screw portion at the tip of the stem portion 10a, thereby allowing the constant velocity on the outboard side. The joint outer ring 10 of the joint 2 is connected to the inner member 33.

As shown in an enlarged view in FIG. 2, the strain detection means 5 includes a detected portion 6 provided on the outer peripheral surface of the intermediate portion in the axial direction of the drive shaft 4, and a non-contact facing the outer periphery of the detected portion 6. And a detection unit 7 that detects a change in the detected unit 6.
The detected portion 6 is made of a metal ring having an outer diameter surface as a magnetostriction portion 6a and an inner diameter surface as a serration portion 6b. The detected portion 6 made of this metal ring is fitted on the outer peripheral surface of the drive shaft 4 by press-fitting the serration portion 6b into the serration portion 4a formed on the outer peripheral surface of the axial intermediate portion of the drive shaft 4. It is fixed. The magnetostrictive portion 6a on the outer diameter surface of the detected portion 6 has a plurality of grooves 25 arranged in the circumferential direction, and the direction of the grooves 25 is inclined by a predetermined angle with respect to the axis. Thus, by providing the plurality of inclined grooves 25 arranged in the circumferential direction in the magnetostrictive portion 6a of the detected portion 6, the magnetostrictive characteristics of the detected portion 6 can be improved and the detection sensitivity can be increased.

  The serration part 6b of the detected part 6 has a structure in which the intermediate part in the axial direction is deleted and arranged separately at both ends. That is, the axial middle portion of the inner diameter surface of the detected portion 6 has a larger diameter than both ends, and serration portions 6b are provided at both end portions. When the serration portion 6b is provided over the entire length in the axial direction of the detected portion 6 instead of the separate arrangement, the serration portion 6a does not necessarily hit the serration portion 4a of the drive shaft 4 over the entire length. Depending on the case, only the leftmost half part in FIG. 2, only the rightmost half part, or only the central part may be hit. As described above, when the coupling of the detected portion 6 to the drive shaft 4 becomes unstable, the variation in magnetostriction characteristics of the detected portion 6 increases, and the reliability is impaired. Therefore, as described above, the serration portion 6a of the detected portion 6 is separated and arranged at both ends, so that the detected portion 6 can be stably coupled to the drive shaft 4 and the distortion of the drive shaft 4 can be detected. The detection unit 6 can be reflected reliably.

In order to increase the magnetostriction characteristics of the detected portion 6, here, as the magnetostrictive material to be the detected portion 6, a material obtained by diffusing aluminum into a metal base material such as carbon steel or chromium-molybdenum steel is used. The metal surface is made of an alloy layer.
As a method for diffusing aluminum in the metal surface layer in this case, a closed container containing a metal base material and aluminum powder is heated to around 900 ° C. The diffusion depth of aluminum varies depending on the processing method and processing time, but here, the aluminum is processed to have a range of about several tens of μm to 100 μm. The aluminum diffusion treatment is performed by diffusing and distributing aluminum in an inclined manner so that the concentration gradually increases in the structural steel, which is a metal base material. Thereby, the Fe-Al alloy of the magnetostriction diffusion layer having high magnetostriction characteristics can be obtained without reducing the mechanical strength of the metal base material.

  When aluminum is distributed from the metal surface so as to have a gradient concentration, it is preferable to diffuse aluminum from the metal surface in a high temperature atmosphere. By diffusing aluminum in this way, it is possible to form a diffusion layer in which the concentration of aluminum gradually increases while drawing a gentle curve concentration curve from the surface toward the center in the steel material as the base material. This graded concentration aluminum diffusion layer becomes a uniform alloy layer without pores as in the case of overlay spraying, and can greatly suppress the occurrence of early cracks due to fatigue. Further, no cracking occurs during the heat treatment.

  In addition, as a magnetostrictive material used as the to-be-detected part 6, you may use the thing produced from the bulk material of the Fe-Al alloy, However In this case, a magnetostrictive material is brittle and workability will fall. On the other hand, in the magnetostrictive material by the diffusion treatment described above, by performing the diffusion treatment of aluminum after the completion of the machining of the metal base material, the same workability as that of a normal steel material can be secured, and the productivity can be remarkably improved. it can. As a result, the cost can be reduced.

  The detected part 6 may be Fe-Al clad steel. This Fe—Al clad steel is stronger in strength than the Fe—Al bulk, and has a strong bonding strength with a base material made of carbon steel. Moreover, since the magnetostrictive characteristics are excellent, an improvement in sensitivity can be expected.

An inner ring 14 of the bearing 13 is fitted to the inboard side of the drive shaft 4 adjacent to the detected portion 6. In the outer ring 15 of the bearing 13, the detection portion 7 is provided on the inner diameter surface of the overhanging end portion 15 a that extends to the outer peripheral side of the detected portion 6.
The bearing 13 is composed of, for example, a rolling bearing in which balls 16 as rolling elements are interposed between the inner and outer rings 14 and 15, and both ends of the annular space formed between the inner and outer rings 14 and 15 are contact-type seal members 17 and 18. Sealed.
The detection unit 7 includes a coil winding that detects the magnetostriction change of the detected unit 6 over the entire circumference of the detected unit 6.

  The outer ring 15 of the bearing 13 is fixed to a fixing portion 20 on the vehicle body side through an elastic body 19 made of, for example, a coil spring, thereby preventing the bearing outer ring 15 from rotating. Specifically, one end of the elastic body 19 is locked to the mounting member 21 provided across the protruding end portion 15a of the bearing outer ring 15 and a part of the detecting portion 7, and the fixing portion on the vehicle body side The other end of the elastic body 19 is locked to a mounting member 22 provided in the engine 20. As shown in FIG. 1, the elastic body 19 in this case is arranged in the vehicle advancing / retreating direction that is perpendicular to the vertical movement direction of the wheels.

  The anti-rotation structure of the bearing 13 via the elastic body 19 is effective as follows from the viewpoint of durability. In other words, the constant velocity universal joint 1 is given an operating angle by the movement of the wheels, that is, the front and rear movements of the wheels by the so-called steering angle and the vertical movements of the wheels by the road conditions. In particular, the vertical movement of the wheel is larger than the longitudinal movement due to the steer angle. Therefore, when the elastic body 19 for preventing rotation is fixed on the upper side of the vehicle, for example, the expansion / contraction stroke of the elastic body 19 becomes large and there is a problem in durability. Remains. In this embodiment, the elastic body 19 that supports the outer ring 15 of the bearing 13 is arranged in a vehicle advancing / retreating direction that is perpendicular to the vertical movement direction of the wheel. Thus, the expansion / contraction stroke of the elastic body 19 accompanying the vertical movement of the wheel can be reduced, and the durability is improved.

On the outboard side adjacent to the bearing 13, a contact-type seal member 23 that seals between the protruding end portion 15 a of the bearing outer ring 15 and the drive shaft 4 is provided. Thereby, the detected part 6 and the detecting part 7 of the strain detecting means 5 arranged between the drive shaft 4 and the overhanging end part 15a are isolated from the outside in an airtight manner. As a result, foreign matter can be prevented from entering the space between the drive shaft 4 and the bearing outer ring 15 in which the detected part 6 and the detection part 7, which are components of the strain detection means 5, are arranged.
Further, a signal cord 24 for connecting the detection unit 7 and a signal processing unit (not shown) on the vehicle body side is wired toward the vehicle body side through the seal member 23. As described above, the strain detecting means 5 is configured by the serration portion 4 a, the detected portion 6, the detecting portion 7, the bearing 13, and the elastic body 19 of the drive shaft 4.

  According to the constant velocity universal joint device 1 with the torque detection function of this configuration, one of the constant velocity universal joint 2 on the outboard side, the constant velocity universal joint 3 on the inboard side, and the two constant velocity universal joints 2 and 3 is provided. In the constant velocity universal joint device 1 having the drive shaft 4 connected to the members 9 and 11 at both ends, the strain detection means 5 for detecting strain due to the torque acting on the drive shaft 4 is provided, so that it acts on each wheel. Torque can be measured. Since the torque acting on each wheel is detected, it is suitable for torque detection in a vehicle not having a propeller shaft such as an FF vehicle, a 4WD vehicle, or the like. Since the strain detection means 5 detects the torque acting on the drive shaft 4, it can be installed in a wide space around the drive shaft 4, and the installation location can be easily obtained. Since the drive shaft 4 is a long component in the drive transmission system, distortion due to torque is greater than that of other components. Therefore, torque detection by strain detection can be performed with relatively high accuracy.

It is a horizontal sectional view of the constant velocity universal joint device with a torque detection function concerning one embodiment of this invention. It is a horizontal sectional view which expands and shows the component of the strain detection means in the equivalent speed universal joint device. It is explanatory drawing of the fluctuation | variation accompanying the wheel vertical motion of the distortion | strain detection means in an equivalent speed universal joint apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Constant velocity universal joint apparatus with a torque detection function 2 ... Outboard side constant velocity universal joint 3 ... Inboard side constant velocity universal joint 4 ... Drive shaft 4a ... Serration part 5 ... Strain detection means 6 ... Detected part 6a ... Magnetostrictive part 6b ... Serration part 7 ... Detection part 8 ... Differential machines 9 and 11 ... Joint inner ring 13 ... Bearing 14 ... Inner ring 15 ... Outer ring 15a ... Overhang end part 19 ... Elastic body 20 ... Fixed part on the vehicle body side (engine)
23... Sealing member 25...

Claims (11)

  A constant velocity universal joint on the outboard side arranged on the wheel side of the automobile, a constant velocity universal joint on the inboard side fixed to the differential side, a joint member on one side of the outboard side constant velocity universal joint, and an inboard In a constant velocity universal joint device having a drive shaft connected at both ends to one joint member of a board side constant velocity universal joint, a strain detection means is provided for detecting distortion of the drive shaft due to torque acting on the drive shaft. A constant velocity universal joint device with a torque detection function.   2. The torque detection according to claim 1, wherein the strain detecting means includes a detected portion provided on the drive shaft and a detecting portion provided on a fixed portion fixed to a vehicle body to detect a change in the detected portion. Constant velocity universal joint device with function.   In claim 1, a serration portion is provided in a part of the drive shaft, a detected portion including a magnetostrictive portion having a serration portion press-fitted into the serration portion on an inner diameter surface is provided, and in parallel with the detected portion, A bearing in which an inner ring is fitted to the drive shaft is arranged, a detection unit for detecting a magnetostriction change of the detected portion is provided in an inner diameter part of the outer ring of the bearing, and the outer ring of the bearing is fixed to a fixed part fixed to the vehicle body. A constant velocity with a torque detection function, which is fixed through an elastic body to prevent the outer ring from rotating, and wherein the strain detection means includes the serration portion, the detected portion, the bearing, the detection portion, and the elastic body. Universal joint device.   4. The constant velocity universal joint device with a torque detection function according to claim 3, wherein a seal member is provided between the outer ring of the bearing and the drive shaft.   4. The constant velocity universal joint device with a torque detection function according to claim 2, wherein the detection unit is a coil.   4. The constant velocity universal joint device with a torque detection function according to claim 2, wherein the detected portion has a plurality of grooves on the outer diameter, and the grooves are inclined with respect to the axis.   4. The constant velocity universal joint device with a torque detection function according to claim 3, wherein the serration portion of the detected portion has a structure in which the serration portions are left at both ends and the central portion is omitted.   4. The constant velocity universal joint device with a torque detection function according to claim 2, wherein the detected portion is a metal surface in which aluminum is diffused in a metal base material and an alloy layer is formed on the surface.   4. The constant velocity universal joint device with a torque detection function according to claim 2, wherein the detected portion uses a clad steel of Fe—Al alloy.   4. The constant velocity universal joint device with a torque detection function according to claim 2, wherein a magnetostrictive material made of a bulk material is used for the detected portion.   4. The constant velocity universal joint device with a torque detection function according to claim 3, wherein the elastic body supporting the outer ring is supported in a direction perpendicular to the vertical movement of the wheel in the forward or backward direction of the vehicle.

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