JP2008298583A - Axle load measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To downsize an axle load measurement device including a load sensor for analyzing component force working to wheels of a motorcycle. <P>SOLUTION: An axle 5 is fixedly supported on a pair of right and left front forks. The axle 5 rotatably supports a wheel 2 via bearings 6L and 6R provided on the left and the right. A membrane sensor 17 is interposed between inner wheels of the bearings 6L and 6R and the axle 5. The membrane sensor 17 is provided together with a protective ring 18 between the axle 5 and the bearings 6L and 6R. The membrane sensor 17 includes protrusions 172-175 in four directions so that component force in upward, downward, forward and backward directions of a vehicle body can be measured. An output of the membrane sensor 17 detected by the protrusions 172-175 is applied to computation of translational three-component force and moment of each axis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an axial load measuring device, and more particularly to an axial load measuring device suitable for measuring an acting force on a shaft.

2. Description of the Related Art Conventionally, a rotating body acting force measuring device that measures an acting force of a rotating body on a shaft is known. When the wheel is a rotating body, for example, the acting force of the wheel is measured in order to detect the load balance of the vehicle body. Japanese Patent Application Laid-Open No. 11-173929 proposes a wheel action force measuring device in which an axle that is rotatably supported by a wheel and fixedly supported by a suspension device is configured as a force load cell. This apparatus has an advantage that the structure can be simplified because the strain detection value is taken out from the strain gauge constituting the load cell without using a slip ring or the like.
Japanese Patent Laid-Open No. 11-173929

  The wheel action force measuring device disclosed in Patent Document 1 is useful in that a slip ring or the like is not required. However, because the volume of the transmission part for transmitting force to the load cell and the frame part and base part for supporting the transmission part are large, the overall size tends to be large, and there are many design modification points for existing parts to secure the mounting space. There is a fear. Moreover, since the apparatus weight is large, it may be considered that the measured value itself is affected.

  An object of the present invention is to provide an axial load measuring apparatus that can measure the acting force of a rotating body without minimizing the mounting space of the apparatus and without significant design change.

  The present invention for solving the above problems includes a shaft that is fixedly supported, a bearing that is provided on the shaft and rotatably supports a rotating body with an outer ring, an outer peripheral surface of the shaft, and an inner ring of the bearing. And a thin film sensor that detects a load in the front-rear and vertical directions with respect to the shaft.

  The present invention also includes a shaft that is fixedly supported, a bearing that is provided at a plurality of locations in the longitudinal direction of the shaft, and that rotatably supports a rotating body with an outer ring, an outer peripheral surface of the shaft, and the plurality of bearings. A second feature is that a thin film sensor that is disposed between the inner ring and detects the load in the front-rear and vertical directions with respect to the shaft is provided.

  According to a third aspect of the present invention, the shaft is a cylindrical hollow body, and a hole penetrating from the outer peripheral surface of the shaft toward the inner peripheral surface of the shaft is provided in the vicinity of the thin film sensor. There is.

  The present invention has a fourth feature in that a protective ring is disposed on the outer periphery of the thin film sensor, and an inner ring of the bearing faces the outer periphery of the protective ring. The thin film sensor and the protective ring are A fifth feature is that a protruding portion is formed on one side of the thin film sensor and the protective ring so as to contact each other only at portions corresponding to the load detection positions in the front-rear and vertical directions.

  Furthermore, the present invention provides a bearing in which an outer ring is fixedly supported by a bearing support member, a shaft rotatably supported by the inner ring of the bearing and connected to a rotating body, the bearing support member, and an outer ring of the bearing And a thin film sensor for detecting a load in the front-rear and up-down directions with respect to the shaft.

  The present invention also provides a plurality of bearings in which an outer ring is fixedly supported by a bearing support member, a shaft that is rotatably supported by an inner ring of the plurality of bearings, and that is connected to a rotating body, and the bearing support member. A seventh feature is that a thin film sensor is disposed between the outer ring of the bearing and detects a load in the front-rear and vertical directions with respect to the shaft.

In addition, the present invention has an eighth feature in that a protective ring is disposed on the inner periphery of the thin film sensor, and the outer ring of the bearing faces the inner periphery of the protective ring.
Further, the present invention provides the thin film sensor and the outer ring of the bearing on either side of the thin film sensor and the outer ring of the bearing so that the outer ring of the thin film sensor and the bearing come into contact with each other only at the portion corresponding to the load detection position in the front-rear and vertical directions. A ninth feature is that the protruding portion is formed.

  The present invention also provides an axle that is fixedly supported by a pair of left and right suspensions, a bearing that is provided at two locations in the longitudinal direction of the axle, and that rotatably supports a wheel with an outer ring, and an outer peripheral surface of the axle. A thin film sensor disposed between the inner rings of the plurality of bearings, for detecting a longitudinal and vertical load on the axle, and a protective ring disposed on an outer periphery of the thin film sensor; Has a tenth feature in that it faces the outer periphery of the protective ring.

  Further, the present invention is characterized in that the wheel or the rotating body is a motorcycle wheel, and the detection output of the thin film sensor is used to calculate a translational three-component force of the shaft and a moment related to the shaft of the translational component force. There is an eleventh feature.

  According to the invention having the above first to eleventh features, the thin film sensor is interposed only by forming a slight gap between the bearing and the shaft or between the bearing and the bearing support member that supports the bearing. This makes it possible to measure the pressure acting in the front-rear and up-down directions on a shaft, for example, an axle, without significantly changing the design of the bearing structure of the rotating body, for example, a wheel. In particular, the thin film sensor itself is lightweight, and the influence of the weight of the thin film sensor on the shaft can be eliminated.

  According to the present invention having the second feature, the output of the thin film sensor can be output without using complicated electrical connection means such as a slip ring by means of a lead wire or the like that can pass through the through hole of the shaft. Can be pulled out.

  According to the present invention having the fifth or ninth feature, the force acting between the bearing and the thin film sensor is concentrated only on a desired portion, thereby improving the sensitivity of the thin film sensor and increasing the detection accuracy. It is possible to obtain. Further, according to the present invention having the fourth or eighth feature, the thin film sensor can be protected by the protective ring.

  According to the present invention having the eleventh feature, the detected pressure value is used for the calculation of the translational three-component force and moment with respect to the axle of the motorcycle, contributing to the field of behavior analysis during traveling of the motorcycle. can do.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is an exploded perspective view of the front wheel of the motorcycle equipped with the axial load measuring device according to the embodiment of the present invention. In FIG. 3, the front wheel 1 as a rotating body includes a wheel 2, a tire 3 attached to the outer peripheral surface of the wheel 2, brake disks 4 </ b> L and 4 </ b> R attached to both side surfaces of the wheel 2, and a hollow cylindrical axle. 5. Further, the components of the front wheel 1 include a distance collar 8 that determines the distance between the bearings 6L and 6R that support the axle 5, the distance between the bearings 6L and 6R, and the positional relationship between the bearings 6L and 6R, the axle 5, and the front fork. , And dust seals 9L and 9R, wheel collars 10L and 10R, axle bolts 11 and the like.

  FIG. 3 shows a front fork case which is a lower portion of the front fork as a suspension device for the front wheel 1 provided on the left and right sides with the front wheel 1 interposed therebetween. Although the left front fork case 12L is shown here, the right side fork case 12L is similarly formed. The front fork case 12L is a cylindrical body having an open upper end and accommodates a front fork pipe and a damper (not shown). An axle hole 13 </ b> L is provided at the lower end of the front fork case 12 </ b> L to insert and support the tip of the axle 5. In addition, since the opposite side to the protruding tip of both ends of the axle 5 is formed with a large diameter, the axle hole 13L of the left front fork case 12L that supports the large diameter portion (both see FIG. 4). The diameter of the front fork case 12R on the right side is set larger.

  FIG. 4 is a cross-sectional view of the main part in a state where the front wheels and the front fork case are assembled, and is a view seen from the front part of the vehicle body. In FIG. 4, a bearing 6 </ b> L is disposed on one side of the hub 14 of the wheel 2, and a bearing 6 </ b> R is disposed on the other side of the hub 14. Dust seals 9L and 9R are disposed outside the bearings 6L and 6R, respectively. A distance collar 8 for determining the distance between the bearings 6L and 6R is disposed between the inner rings of the bearings 6L and 6R. In addition, wheel collars 10L and 10R are disposed outside the bearing 6L and outside the bearing 6R, respectively.

  The axle 5 has a long small diameter portion and a short large diameter portion. The small diameter portion penetrates the wheel collar 10L, the bearing 6L, the distance collar 8, the bearing 6R, and the wheel collar 10R, and the tip of the wheel collar 10R. It protrudes from. The front end of the axle 5 protruding from the wheel collar 10R is inserted into the axle hole 13R of the front fork case 12R. An internal thread is formed at the end of the axle 5, and an axle bolt 11 is screwed into the internal thread. The step surface between the large diameter portion and the small diameter portion of the axle 5 is in contact with the end portion of the wheel collar 10L. By screwing the axle bolt 11 into the female screw at the tip of the axle 5, the inner side surface of the front fork case 12R and the wheel collar 10R. And the contact portion between the stepped surface of the axle 5 and the end surface of the wheel collar 10L are in close contact with each other, and the positional relationship between the respective portions is determined. The large diameter portion of the axle 5 is fitted into an axle hole 13L formed in the front fork case 12L. The brake disks 4L and 4R are attached around the end surface of the hub 14 using bolts 15. Thin film sensors are provided between the inner rings of the bearings 6L and 6R and the axle 5.

  FIG. 1 is an enlarged cross-sectional view of a main part showing an axial load measuring device, and FIG. 2 is a view taken along the line AA in FIG. In any figure, the same reference numerals as those in FIGS. 3 and 4 denote the same parts. In FIG. 2, directions corresponding to the front-rear direction and the up-down direction of the motorcycle are indicated by arrows with front, rear, upper, and lower signs. The axial load measuring device 16 is provided at two locations on the axle 5, that is, at both ends of the hub 14, but since both have the same structure, the axial load measuring device 16 is provided on the left side of the hub 14 as a representative. The axial load measuring device 16 measures the load acting between the tire 3 and the ground contact surface of the tire 3 via the bearing 6L.

The axial load measuring device 16 has a structure in which a thin film sensor 17 and a protective ring 18 are fitted between the outer peripheral surface of the axle 5 and the inner ring of the bearing 6L. As the thin film sensor 17, a known sensor that outputs a detection signal corresponding to an applied pressure can be used. For example, an insulating film such as Al ₂ O ₃ or SiO ₂ is PVD deposited on the surface of a thin metal (stainless steel, etc.) plate, and a strain sensor made of CrN, CuNi, or NiCr is deposited thereon by PVD deposition. Those are preferred. However, as long as it is a thin film that can detect the function of the present invention, that is, the axial load, it can be selected from various known ones.

  The protection ring 18 is made of metal and serves to protect the thin film sensor 17 when the thin film sensor 17 is fitted between the axle 5 and the bearing 6L. The axle 5 is formed with a small diameter by cutting the outer periphery in order to secure a space for storing the thin film sensor 17. It should be noted that the shaved portion of the axle 5 is exaggerated and deeply drawn for understanding the shape.

  As can be understood from FIG. 2, the thin film sensor 17 has an annular inner peripheral portion 171 along the outer periphery of the axle 5 and four projecting portions 172, 173, and 174 disposed on the outer periphery and four upper and lower and left and right sides (front and rear of the vehicle body). , And 175. Thus, by providing the projecting portions 172 to 175 on the top, bottom, left and right, the load from the top, bottom, left and right directions can be detected reliably.

  As a method for fixing the thin film sensor 17 between the axle 5 and the bearing 6L, for example, a shrink fitting process can be used. First, the thin film sensor 17 is fitted on the small diameter portion of the axle 5, and then the heated protective ring 18 is put on the outer periphery of the thin film sensor 17 and then cooled. By this operation, once heated, the protective ring 17 contracts by being cooled and is brought into close contact with the outer periphery of the thin film sensor 17, thereby bringing the thin film sensor 17 into close contact with the outer periphery of the axle 5.

  Thus, the projecting portions 172 to 175 of the thin film sensor 17 provided between the axle 5 and the bearing 6L are electrically connected to an external signal processing device via lead wires (not shown). For example, a hole 20 penetrating the wall portion of the axle 5 may be drilled, and the lead wire may be pulled out through the axle 5 through the hole 20, or the lead wire may be pulled out through the wheel collar 10L. You may pull it out.

  In addition, although the thin film sensor 17 showed the example comprised by the four protrusion parts 172-175 and the cyclic | annular part 171 used as a base, you may make it arrange | position four separate thin film sensors vertically and horizontally. That is, the annular portion 171 serving as the base can be omitted.

  Thus, the thin film sensor 17 provided between the axle 5 and the bearing 6L can measure the acting force of the tire 3 on the ground contact portion. The acting force is detected as six component forces. That is, three translational component forces and three moments around each axis of the three translational component forces.

  FIG. 5 is a diagram showing component forces and moments acting on the axle. In FIG. 5, the longitudinal direction of the motorcycle is the x axis, the extending direction of the axle 5 is the y axis, and the vertical direction of the motorcycle is the z axis. In this case, translational component forces Fx, Fy, Fz act along each axis, and moments Mx, My, Mz act around each axis. The translation component force Fx is detected by the outputs of the projecting portions 172 and 174 of the left and right thin film sensors 17 provided on the axle 5, and the translation component force Fz is detected by the outputs of the projecting portions 173 and 175 of the upper and lower thin film sensors 17. Then, the moments Mx and Mz are obtained by calculation based on the translational component forces Fx and Fz. Since the axle 5 is rotatably supported by the bearing 6L, the translational component force Fy in the y-axis direction along the axle 5 and the moment My around the y-axis cannot be calculated.

  However, on the tire contact surface, the translational component forces Fx, Fy, Fz and moments Mx, My, Mz based on them can be calculated based on the distance between the axle 5 and the contact surface and the detection signal of the thin film sensor 17. it can.

  The acting force on the ground contact surface of the motorcycle can be analyzed by the component force on the axle directly or indirectly calculated by the thin film sensor. For example, when the motorcycle is turning right, the vehicle body is tilted to the right. At this time, the resultant force of gravity and the centrifugal force generated toward the outside of the turning portion is generated in a direction directly below the vehicle body. Therefore, in this state, the component force Fz in the z-axis direction is increased, and a detection result in which the vehicle weight is increased is obtained. However, the tire 3 generates a moment Mz around the steering axis (that is, around the z axis) by steering during turning. At the same time, a component force Fy in the y-axis direction is generated by the centrifugal force, and a moment acts on the axle 5 to cause a difference between the component forces Fz and Fx in each of the left and right thin film sensors 17. Therefore, moments Tx and Tz generated based on the difference between the component forces can be calculated.

  In addition, when the motorcycle rides on a road step, it first receives a force from the front, so that the component force Fx rises, and thereafter, the component force Fz changes due to the deformation of the tire 3 or the movement of the suspension.

  The axle load measuring device of this embodiment is useful as a device for analyzing such behavior in detail and precision. In particular, according to the present embodiment, since the thin film sensor 17 is provided between the inner ring on the fixed side of the bearings 6L and 6R and the axle 5, the thin film sensor 17 is fixed regardless of the rotation of the wheel. Thus, the output of the thin film sensor 17 can be drawn out without using a slip ring or the like.

  The present invention is not limited to this embodiment. For example, the present invention can be applied to a structure in which the outer ring of the bearings 6L and 6R is fixed and the inner ring is rotated. FIG. 6 is a cross-sectional view of a main part of the axial load measuring device according to the second embodiment. In the figure, a bearing 22 is supported by a bearing box (bearing support member) 21, and a shaft 23 is rotatably supported by the bearing 22. The bearing 22 includes an outer ring 221 and an inner ring 221, and a thin film sensor 24 is disposed on the outer periphery of the outer ring 221, and a protective ring 25 is disposed on the outer periphery of the thin film sensor 24. That is, the protective ring 25 is fitted along the outer peripheral surface of the outer ring of the bearing, the thin film sensor is fitted on the outer circumference, and the bearing 22 is accommodated in the bearing box 21 via the protective ring 25 and the thin film sensor 24. In the case of a motorcycle, the bearing box 21 can be provided in the front fork case 13 shown in FIG. Also in this case, the thin film sensor 24 is formed with a protruding portion directed toward the protective ring, as shown in FIG.

  Further, the thin film sensor 17 is provided with projecting portions 172 to 175 so that pressure or load can be reliably detected in the vertical and longitudinal directions of the vehicle body, but instead of this, four projecting portions are formed on the protective ring 18 side. The thin film sensor 17 side may have a uniform thickness. Further, the protective ring 17 may be omitted, and only the thin film sensor 17 may be disposed between the axle 5 and the bearings 6L and 6R.

  In the present invention, not only the force acting on the front wheel shaft but also the acting force on the rear wheel can be measured by an axial load measuring device using a thin film sensor. Moreover, although the case where the shaft is an axle of a motorcycle has been described in the above embodiment, the present invention is not limited thereto, and the shaft may be a crankshaft of an engine, a counter shaft of a deceleration shaft, or the like.

  Furthermore, in the above-described embodiment, the structure in which the axle is supported by two bearings is taken as an example. However, the present invention is not limited to this, and can be applied to a structure in which a single shaft is supported by more bearings. It can also be applied to a structure in which a shaft is supported by a single bearing.

It is an expanded sectional view showing the important section of the axle load measuring device concerning one embodiment of the present invention. It is sectional drawing in the AA position of FIG. It is a perspective view of the front wheel of the motorcycle carrying an axle load measuring device. It is sectional drawing which shows the principal part of the front wheel of the motorcycle carrying an axle load measuring device. It is a figure which shows the component force and moment with respect to the axle shaft of a front wheel. It is principal part sectional drawing of the axial load measuring device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motorcycle, 2 ... Wheel (rotary body, wheel), 3 ... Tire, 5, 23 ... Axle (axis), 6L, 6R ... Bearing, 8 ... Distance collar, 12L, 12R ... Front fork, 14 ... Hub, 17 ... Thin film sensor 18, 25 ... Protective ring

Claims (12)

A fixedly supported shaft;
A bearing provided on the shaft and rotatably supporting the rotating body with an outer ring;
A shaft load measuring device, comprising: a thin film sensor which is disposed between an outer peripheral surface of the shaft and an inner ring of the bearing and detects a longitudinal and vertical load on the shaft. A fixedly supported shaft;
A bearing provided at a plurality of locations in the longitudinal direction of the shaft, and rotatably supporting the rotating body with an outer ring;
An axial load measuring apparatus comprising: a thin film sensor that is disposed between an outer peripheral surface of the shaft and inner rings of the plurality of bearings and detects a load in the front-rear and vertical directions with respect to the shaft.   3. The shaft according to claim 1, wherein the shaft is a cylindrical hollow body, and a hole penetrating from the outer peripheral surface of the shaft toward the inner peripheral surface of the shaft is provided in the vicinity of the thin film sensor. Axial load measuring device.   The axial load measuring device according to any one of claims 1 to 3, wherein a protective ring is disposed on an outer periphery of the thin film sensor, and an inner ring of the bearing faces an outer periphery of the protective ring.   A protruding portion is formed on one side of the thin film sensor and the protective ring so that the thin film sensor and the protective ring are in contact with each other only at the portion corresponding to the load detection position in the front-rear and vertical directions. The axial load measuring device according to claim 4. A bearing in which the outer ring is fixedly supported by a bearing support member;
A shaft rotatably supported by the inner ring of the bearing and connected to the rotating body;
An axial load measuring device comprising: a thin film sensor which is disposed between the bearing support member and an outer ring of the bearing and detects a longitudinal and vertical load on the shaft. A plurality of bearings in which the outer ring is fixedly supported by bearing support members;
A shaft rotatably supported by inner rings of the plurality of bearings and connected to a rotating body;
A shaft load measuring device, comprising: a thin film sensor which is disposed between the bearing support member and an outer ring of the bearing and detects a load in the front-rear and vertical directions with respect to the shaft.   The axial load measuring device according to claim 6 or 7, wherein a protective ring is disposed on an inner periphery of the thin film sensor, and an outer ring of the bearing faces the inner periphery of the protective ring.   A protruding portion is formed on either side of the thin film sensor and the outer ring of the bearing so that the outer ring of the thin film sensor and the bearing abuts each other only at the portion corresponding to the load detection position in the front-rear and vertical directions. The axial load measuring device according to claim 8, wherein An axle fixedly supported by a pair of left and right suspensions;
A bearing provided at two locations in the longitudinal direction of the axle, and rotatably supporting a wheel by an outer ring;
A thin film sensor that is disposed between an outer peripheral surface of the axle and inner rings of the plurality of bearings, and detects a longitudinal and vertical load on the axle;
A protective ring disposed on the outer periphery of the thin film sensor;
An axial load measuring apparatus comprising an inner ring of the bearing facing an outer periphery of the protective ring.   6. The rotating body is a wheel of a motorcycle, and the detection output of the thin film sensor is used to calculate a translational three-component force of the shaft and a moment about the shaft of the translational component force. The axial load measuring device according to any one of the above.   11. The shaft according to claim 10, wherein the wheel is a wheel of a motorcycle, and the detection output of the thin film sensor is used to calculate a translational three-component force of the shaft and a moment related to the axis of the translational component force. Load measuring device.

Images