JP4989412B2 - Digital torque measuring instrument - Google Patents

Description

  The present invention is a digital torque measuring device equipped with a torque sensor, which can accurately measure even a small torque, and is small and lightweight, so it can be rotated by holding the torque measuring device main body in hand. It is possible to measure body torque.

  Conventionally, as a torque measuring instrument for measuring a relatively small torque of about 0.05 cN m to 150 cN m, a small torque gauge that can be used by hand is proposed. This torque gauge is used, for example, for measuring the torque required for rotation of a rotating body such as a rotary knob provided in an electronic device or precision device.

  For example, Patent Document 1 describes an example of a torque gauge. This torque gauge includes a cylindrical grip portion, a main shaft provided at the shaft center of the grip portion, a spiral spring mounted around the main shaft, a chuck for gripping an object to be measured, and the like. The spiral spring has an inner end fixed to the main shaft and an outer end fixed to the grip portion.

  In the operation for measuring the torque with the torque gauge, first, a rotary body such as a knob to be measured is held and fixed by the chuck, and the user rotates the torque gauge in this state. Then, a torque for rotating the torque gauge is input to the spiral spring, and the grip portion and the main shaft rotate relatively while the spiral spring is deformed so as to be wound according to the elastic force. At this time, the torque value applied to the rotating body is expressed by the scale portion in which the torque value converted from the relationship between the torque input to the spiral spring and the deformation amount (displacement amount) generated thereby is engraved. I can know.

  When torque is applied to the rotating body, the rotating body starts rotating when a certain torque is exceeded, and the elastic deformation of the spiral spring disappears and the measured torque decreases. The maximum torque value measured until the body starts rotating is the torque (starting torque) necessary to rotate the rotating body. Therefore, in this torque gauge, if the maximum torque measured before the rotating body starts rotating or a so-called needle-type structure in which the input maximum torque is displayed on the scale, Measure body starting torque.

  Thus, in a conventional torque gauge that measures the starting torque of a rotating body, a spiral spring is used as an elastic body for torque measurement, and the relationship between the amount of elastic deformation of the spring and the input torque The torque was measured mechanically. However, in that case, the torque cannot be calculated digitally, and the measured torque cannot be displayed as numerical data, nor can it be directly stored or output.

  On the other hand, in order to measure force such as load and display it digitally, it is necessary to measure force as an electrical signal. Usually, when measuring force and load as such an electrical signal, A load cell configured by attaching a strain gauge to the surface of a strain generating body such as a steel material is used. The load cell measures the applied load by generating a strain by applying a load to a strain generating body such as a steel material and detecting the strain with a strain gauge. Here, the strain gauge is usually formed by attaching a metal foil resistance wire on a synthetic resin base material, and is an electric resistance whose resistance value changes due to its own strain. Usually, a bridge circuit is configured using this strain gauge, and is used by being attached to an object for detecting strain. When distortion occurs, a potential difference is generated at an intermediate point of the bridge circuit, and a voltage corresponding to the distortion amount is output. Therefore, the distortion amount and the applied force of the measurement object can be measured from the output.

  And the apparatus which can measure a torque with a digital value using such a load cell is also proposed. Patent Document 2 describes a torque check device using a load cell. In this load cell, a steel plate having a strain gauge disposed on the surface is used as a strain generating body, and a torque is applied in the twist direction of the steel plate. Are vertically installed in the direction of the rotation axis. When torque is input to this load cell by the torque check device, the steel plate, which is the strain generating body, is twisted, and the strain gauge placed on the surface detects the strain due to the twist, and the torque is measured digitally. A value can be obtained.

In addition, Patent Document 3 proposes a torque detection device using a so-called Robertal type load cell that uses a plate-like steel material with a hollow center portion as a strain body. In the case of this torque detection device, the torque in the rotational direction is converted into a linear force by the worm gear, and the load cell is deformed by acting on the load cell, and the resulting strain is detected by a strain gauge (strain sensor). Seeking electrical.
JP 2006-71468 A JP-A-10-78361 JP 2003-307461 A

  However, although the torque measuring devices described in Patent Documents 2 and 3 described above can measure torque as an electrical signal and obtain a torque value digitally, both have a complicated structure and mechanism, and can be obtained manually. It is difficult to apply to a small torque measuring instrument that is used with a measuring instrument.

  Further, the load cell strain body as conventionally proposed is also large in the height direction in the case of the load cell described in Patent Document 2, and in order to be used for the small torque measuring device, torque measurement is required. There is a problem that the vessel must be enlarged in the longitudinal direction (axial direction).

  In addition, as described in Patent Document 3, in the configuration using a gear member such as a worm gear, the torque measuring device is similarly enlarged, and friction is generated in the gear portion through the gear member. There is a problem that the accuracy of the measurement is lowered.

  As another problem, such a portable small-sized torque measuring instrument needs to measure a relatively small torque with high accuracy. Therefore, a straight line between the input torque and the output of the torque sensor used in the torque measuring instrument. Higher performance is required. For example, even with a small torque sensor, the linearity of the input torque and the signal output to it is low, and the processing becomes complicated if a large amount of correction is required in the measurement torque calculation processing stage. It becomes difficult to maintain high measurement accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a small digital torque measuring device capable of accurately measuring torque even when the torque of an object to be measured is small.

  The digital torque sensor according to the present invention is a torque measuring instrument main body including a torque sensor configured by disposing a strain gauge on the surface of a strain generating body that is elastically deformed when an external force is applied, and is attached to a measurement object. A digital torque measuring device comprising a mounting member, wherein the torque measuring device main body includes a rotating shaft member for connecting the mounting member to the torque measuring device main body so as to be rotatable relative to the torque measuring device main body, and a base for storing the torque sensor And a processing circuit for calculating the torque value from the signal output from the torque sensor, and a digital display for displaying the torque value, and fixing the mounting member to the measurement object, The torque sensor is elastically deformed by rotating it relative to the object to be measured via the rotating shaft member, and the torque is measured.

  According to the digital torque measuring instrument of the present invention, the torque measuring instrument main body and the torque sensor in the torque measuring instrument main body are small and light, so it can be carried and the torque measuring instrument is held in hand to measure the torque. Is possible.

  In addition, in the digital torque measuring device of the present invention, if a torque sensor having a strain-generating body formed in a spiral shape is used, the direction in which the torque acts is caused to act in the same direction as the direction of rotation of the spiral to generate distortion. Since the torque can be obtained from the strain, the torque can be directly applied to the strain generating body, and the torque can be measured more accurately even if the torque is excellent and the torque is excellent.

  Further, according to the torque measuring instrument of the present invention, since the direction can be changed by opening and closing the display unit that displays the torque value, the torque measuring instrument main body is used at a position away from the user's eye position. However, if the user changes the direction in which the display unit can be visually recognized, the measured torque value can be reliably confirmed.

  Hereinafter, a digital torque measuring device according to the present invention will be described based on the present embodiment shown in the drawings.

  The torque measuring instrument of the present embodiment is, for example, a torque when a rotating body such as a rotating shaft of a volume knob starts to rotate, in other words, a torque necessary for rotating the rotating body to be measured (hereinafter referred to as a starting torque). It is used when measuring

  First, the torque sensor used for this torque measuring device will be described. As the torque sensor, it is possible to use a normal torque sensor configured by a strain body elastically deformed by an external force and a strain gauge disposed on the surface of the strain body. As a preferred form of the torque sensor used in the measuring instrument, there is a torque sensor 1 having a spiral strain body 2 as shown in FIG.

  The torque sensor 1 shown in FIG. 1 shows a normal state where no external force is applied, (a) is a side view of a portion where a strain gauge 14 is attached, and (b) is a plan view. The torque sensor 1 includes a strain body 2 and a strain gauge 14 attached to the strain body 2. As shown in FIG. 1, the strain body 2 is a band-shaped metal member having a working end 4 to which an external force is input at one end and a fixing end 6 for fixing to a pedestal or the like of a torque measuring device at the other end. It is a single spiral wound in a plane. The working end 4 is the center end of the spiral, and the fixed end 6 is the outer end of the spiral. The working end 4 is formed with a shaft hole through which a torque measuring instrument 100 to be described later is inserted into a rotating shaft connected to the rotating body to be measured. The shaft hole is slid in the rotational direction with respect to the rotating shaft. Insert and fix so that there is no. Therefore, it is preferable that the shaft hole of the working end 4 and the rotation shaft on the torque measuring device 100 side are engaged with each other and formed into a shape that can be fixed in the rotation direction. For example, it is conceivable to form the rotating shaft and the shaft hole in a hexagonal shape, a dodecagonal shape, or the like, or to perform spline processing or serration processing. The fixed end 6 is fixed to the torque measuring device side with a screw or the like.

  In this embodiment, the center end of the torque sensor 1 is the working end 4 and the outer end is the fixed end 6. Conversely, the center end is the fixed end that fixes the torque measuring instrument, and the outer end is the working end. It is good also as an end. Further, the shapes of the working end 4 and the fixed end 6 are not limited thereto, and may be any shape that can be connected to a rotating shaft that inputs torque, or a shape that can be fixed to the torque measuring instrument.

  As a characteristic of the torque sensor 1, the strain generating body 2 has three plane portions 8, 10, and 12 that are linearly represented in the plan view of FIG. As the whole distortion body 2, the point currently formed in the square shape with a rounded corner is mentioned. Of the three plane portions 8, 10, and 12, in the present embodiment, strain gauges 14 (14a, 14b) are provided on both the outer side (outward direction of the spiral) and the inner side (action end 4 side) of the plane portion 8. , 14c, 14d). The strain gauge 14 may be arranged at any of the three plane portions, but is preferably arranged at the plane portion 8 closest to the fixed end 6 for the reason described later. In addition, since these flat portions are formed in order to dispose the strain gauge 14, it is necessary to form the planar portion so as to have a length that allows the strain gauge 14 to be disposed. The height of the side surface to which is attached may be larger than the width at which the strain gauge 14 can be attached.

  Next, a mechanism for detecting torque using the torque sensor 1 composed of the strain body 2 and the strain gauge 14 will be described. First, when a torque acts on the strain generating body 2, for example, in FIG. 1, when a torque in the direction opposite to the clockwise direction (relative to the fixed end 6) acts on the working end 4, the strain generating body. 2 is deformed so as to be wound around the working end 4. Then, the plane portion 8 is also deformed by the deformation of the strain body 2. If it does so, the strain gauges 14a-14d arrange | positioned at the plane part 8 will also deform | transform, and the resistance value of each strain gauge 14a-14d will change. When the resistance values of the strain gauges 14a to 14d change, a voltage is generated in the circuit formed by the strain gauge 14, and the generated voltage has a certain correspondence with the input torque. Therefore, if the correspondence relationship is obtained in advance, the torque value of the external force input from the correspondence relationship can be obtained.

  Next, the arrangement position of the strain gauge 14 described above will be described. Since the strain gauge 14 needs to be affixed on a plane, the strain generating body 2 of the present embodiment has the plane portions 8, 10, and 12 for affixing the strain gauge 14. Even if the strain gauge 14 is affixed to any plane portion, it functions as a torque sensor. However, for each of the three plane portions 8, 10, and 12, the input torque and the voltage generated from the strain gauge 14 (of the torque sensor 1). As a result, the linearity is most excellent when it is arranged on the flat portion 8 formed on the most fixed end 6 side among the three flat portions 8, 10, and 12. And the result that the output of electric power was also large was obtained. Since the linearity between the input torque and the output of the torque sensor 1 is high, the torque can be calculated with fewer corrections, so that the torque value can be accurately measured.

  On the contrary, when the linearity between the input torque and the generated voltage is low, a large correction or a complicated correction is required in the calculation of the torque, and the measurement accuracy is lower than when the linearity is high. Therefore, it is preferable that the linearity of the correspondence relationship is as high as possible.

  Therefore, in the torque sensor 1 using the strain body 2 of the present embodiment, the strain gauge 14 is disposed on the flat surface portion 8 where the linearity between the input torque and the generated voltage is the highest. Of course, it is also possible to arrange the strain gauges 14 on the other plane portions 10 and 12, and in that case, the torque value may be calculated by making necessary corrections.

  Next, with reference to FIG. 2, FIG. 3 and FIG. 4, the digital torque measuring instrument of this embodiment using the above-described torque sensor 1 will be described. FIG. 2 is a cross-sectional view of the torque measuring device 100 of the present embodiment, and FIGS. 3A to 3C show the respective states of the torque measuring device 100 shown in FIG. FIG. 4 is a side view, and FIG. 4 is a top view of the torque measuring device 100. The torque measuring device 100 is configured such that a detachable chuck portion 102 for gripping a rotating measurement object, the chuck portion 102 and the torque measuring device main body 101 are coupled by tightening a screw, and a torque measuring device is connected by a bearing 106. A rotary connecting portion 104 fixed by press fitting or the like to a rotary shaft 110 that can be rotated with little frictional resistance with respect to the main body 101 (the rotary shaft member in the scope of claims is constituted by the rotary shaft 110 and the rotary connecting portion 104) And a processing circuit storage unit 114 in which a processing circuit 200 for calculating a torque value from a voltage generated in the strain gauge 14 is stored. As shown in FIG. 4, a display unit 116 for displaying torque values and an operation unit 118 for performing various operations such as torque value storage processing and reset processing are arranged on the upper surface of the processing circuit storage unit 114. Yes.

  A specific structure of the torque measuring device 100 will be described. The chuck portion 102 can hold the rotating body of the measurement object so as not to be displaced in the rotation direction by the claw portion 102a. The chuck portion 102 is attached to the torque measuring device main body 101 via the rotation connecting portion 104. As described above, the rotation connecting portion 104 is press-fitted and fixed to the rotating shaft 110 rotating with a small amount of frictional resistance with respect to the torque measuring device main body 101 by the bearing 106. The rotating shaft 110 is integrally rotatable relative to the torque measuring device main body 101. Therefore, if the torque sensor 1 (distortion body 2) is not attached to the rotating shaft 110, the chuck portion 102 and the rotating connecting portion 104 are connected to the torque measuring device main body 101 by the rotating shaft 110 and the bearing 106. In contrast, it rotates without resistance.

  Further, the torque measuring device main body 101 is provided with a stopper mechanism 122 which is a rotation restricting member for restricting an angle at which the chuck portion 102 and the rotation connecting portion 104 and the rotation shaft 110 can rotate relative to the torque measuring device main body 101. It has been. This is because when the torque exceeding the measurable range is input to the torque sensor 1 and it is deformed to a state where the measurement accuracy cannot be maintained, or when the large torque is input and the strain generating body 2 is This is to prevent breakage or plastic deformation that makes it unusable.

  The stopper mechanism 122 of the present embodiment is configured by a stopper pin disposed in the torque measuring device main body 101 and a groove portion formed in a peripheral portion on the pedestal portion 108 side of the rotation connecting portion 104 in a range allowing relative rotation. Is done. By engaging the stopper pin with the groove portion, the rotation connecting portion 104 and the torque measuring device main body 101 can relatively rotate only within the range where the groove portion is formed. Therefore, for example, if the rotation angle of the torque sensor 1 that can detect the torque with high accuracy and can maintain the linearity between the input torque and the output is 30 degrees in both directions from the normal state where there is no external force, What is necessary is just to form over the range of 60 degree | times. The stopper mechanism is not limited to the above-described configuration, and the stopper pin may be disposed in the rotation connecting portion 104, the groove portion may be disposed in the torque measuring device main body 101, and the range of the relative rotation described above. Any configuration can be used as long as it can be regulated.

  The torque sensor 1 floats by fixing the working end 4 of the strain generating body 2 to the rotating shaft 110 and fixing the fixed end 6 to a fixed end fixed shaft 112 provided on the pedestal portion 108 of the torque measuring device main body 101. It is installed in the torque measuring instrument main body 101 in a state. By installing the torque sensor 1 in this manner, the chuck portion 102 (the rotation connecting portion 104) rotates with respect to the torque measuring device main body 101 with a resistance corresponding to the elasticity of the strain generating body 2. . Therefore, when no external force in the rotational direction is applied to the torque measuring instrument 100, the strain body 2 is not deformed and is stationary in a normal state where the elastic energy is zero.

  The processing circuit storage unit 114 is normally in a state in which the user can easily hold the torque measuring device 100, for example, in a cylindrical gripping part 101a formed in a polygonal shape (FIG. 3A). )), Until the display unit 116 and the operation unit 118 on the upper surface of the processing circuit storage unit 114 are directed toward the chuck unit 102 (completely opened state) as shown in FIG. It can be opened and closed steplessly. The hinge shaft 120 is moved to an arbitrary position between the normal closed state (FIG. 3A) and the fully opened state (FIG. 3C) by a frictional force or the like. Can be stopped. Thereby, the directions of the display unit 116 and the operation unit 118 provided on the upper surface of the processing circuit storage unit 114 can be changed according to the use situation.

  For example, if the processing circuit storage unit 114 is used in a state in which the processing circuit storage unit 114 is opened obliquely or in a state in which the processing circuit storage unit 114 is opened up to 90 degrees (FIG. 3B), the torque measuring device 100 is located away from the user's eyes, Even when the display unit 116 is used at a position lower than the eye level, the torque can be measured while viewing the display unit 116 because the display unit 116 faces the user. In the fully open state (FIG. 3C), the torque measuring instrument 100 is fixed to a fixed base or the like, and the user observes the display unit 116 from the chuck unit 102 side while measuring the object to be measured. It is also possible to measure torque by rotating.

  The torque measuring device 100 of the present embodiment can open and close the processing circuit storage unit 114 on which the display unit 116 and the operation unit 118 are arranged so that the display unit 116 and the operation unit 118 can be easily observed and operated. Although formed, it is not limited to such a structure, It is good also as a shape fixed to the upper surface of the torque measuring device 100. FIG.

  An operation in the case of measuring torque using the torque measuring device 100 having the above configuration will be described. Note that the processing circuit storage unit 114 is closed.

  First, a rotating body such as a rotating shaft of a knob as a measurement object is inserted into the chuck portion 102, and the chuck portion 102a and the rotating body are firmly fixed by the claw portion 102a so that the chuck portion 102 and the rotating body do not slide or shift in the rotation direction. In this state, the torque measuring device 100 is rotated while holding the grip 101a of the torque measuring device main body 101. Until the rotating body starts to rotate, the torque measuring device main body 101 rotates relative to the rotating connecting portion 104, the chuck portion 102, and the rotating body held by the rotating end holding shaft 112 (fixed end 6). Is relatively rotated around the rotation shaft 110 (the working end 4), and the torque sensor 1 is elastically deformed in a direction in which the spiral shape of the strain generating body 2 is wound or opened. Since a restoring force that attempts to return to the normal state according to the elastic deformation acts on the rotating shaft 110, a force in the rotational direction according to the deformation amount of the strain generating body 2 with respect to the rotating body fixed to the chuck portion 102. That is, torque acts.

  At this time, a strain is generated by elastic deformation of the strain generating body 2, whereby a voltage is generated in the strain gauge 14 attached to the surface of the strain generating body 2, and from the voltage value generated by the processing circuit 200. The torque applied to the rotating body is calculated, and the calculated torque value is displayed on the display unit 118.

  When the force for rotating the torque measuring device main body 101 is increased, that is, when the torque acting on the rotating body is increased, the torque measured by the torque sensor 1 is increased until the rotating body starts to rotate. Then, when a torque exceeding the starting torque, which is a torque necessary for the rotation, is input to the rotating body, the rotating body starts to rotate, and then the torque decreases. Therefore, when the torque input to the rotating body is increased, the maximum torque measured until the rotating body starts rotating becomes the starting torque. Therefore, in the torque measuring device 100 of the present embodiment, when the maximum value (peak value) of the torque is measured after the measurement is started, the maximum value is the starting torque of the rotating body of the measurement object, and the display unit 116 Is displayed.

  When the input torque exceeds the starting torque and the rotating body starts to rotate, the deformation of the strain generating body 2 is eliminated, and the restoring force of the strain generating body 2 and the resistance force of the rotating body (rotational frictional force, etc.) When they are balanced, they stand still.

  With the operation as described above, the starting torque necessary for the rotation of the rotating body can be measured by relatively rotating the torque measuring device 100 and the measurement object.

  Next, the processing circuit 200 that performs torque calculation and other processing / control in the torque measuring device 100 of the present embodiment will be described. As described above, the processing circuit 200 is disposed in the processing circuit storage unit 114. The other components of the torque measuring instrument 100, such as the strain gauge 14, the display unit 116, the operation unit 118, and the like, are illustrated in FIG. Are connected as shown in the circuit diagram shown in FIG.

  The processing circuit 200 amplifies the voltage signal output from the strain gauge 14 or cuts unnecessary signals, and digitally converts the analog signal output from the amplifier / filter unit 201. A / D converter 202 that converts the signal (voltage value), a CPU unit 203 that performs calculation processing from the voltage value to the torque value, display control of the torque value on the display unit 116, and the strain gauges 14a to 14d. The applied voltage control unit 204 controls the voltage applied to the bridge circuit.

  The flow of processing performed in the processing circuit 200 when torque measurement is actually performed using the torque measuring device 100 will be described. When the chuck portion 102 of the torque measuring device 100 is fixed to a rotating body that is a measurement object and the torque measuring device main body 101 is rotated, the strain generating body 2 is elastically deformed to generate distortion. As described above, when strain is generated in the strain generating body 2, a voltage is generated at an intermediate point of the bridge circuit formed by the four strain gauges 14, and an analog signal of the voltage is transmitted to the amplifier / filter unit 201. Amplification and unnecessary signal cutting are performed and output to the A / D converter 202. In the A / D converter 202, the voltage analog signal is converted into a digital signal and output to the CPU unit 203.

  In the CPU unit 203, first, the torque value is calculated from the voltage value of the preset torque value and the voltage value from the voltage value of the digital signal input in the calculation unit 203a. The calculated torque value is output to the display control unit 203b and displayed on the display unit 116. The user can check the torque applied to the rotating body by looking at the torque value displayed on the display unit.

  When the torque measuring device main body 101 is further rotated with respect to the rotating body, the rotating body of the measurement object starts rotating when the torque necessary for the rotation of the rotating body is exceeded. As described above, the maximum value of the torque measured at that time is the starting torque value necessary for rotating the measuring object, and the maximum value is the starting torque of the measuring object on the display unit 116. It is displayed so that it can be understood. The above is the flow of processing in the processing circuit 200 during torque measurement.

  In addition, the torque value determination unit 203c and the applied voltage control unit 204 are configured so that an appropriate voltage is applied to the bridge circuits of the strain gauges 14a to 14d based on the torque value calculated by the calculation unit 203a. The voltage applied from 126 to the strain gauge 14 is controlled.

  The communication data processing unit 203d is means for outputting the measured torque value to an external device such as a computer. Since the torque measuring device 100 according to the present embodiment calculates the torque value as a digital value, the measurement data can be recorded as it is if it is connected to a computer or the like and output. As an output terminal for this purpose, the torque measuring device main body 101 is provided with a USB output unit 124 and the like, and is connected to an external device via the output terminal for communication.

  As described above, according to the present embodiment, it is possible to configure a small torque measuring instrument 100 that can be used by hand even if it is a digital torque measuring instrument. If the torque sensor 1 composed of the strain generating body 2 is used, the size is not increased in the longitudinal direction. Further, in the case of the torque sensor 1, since the strain body 2 can be deformed in the same rotational direction as the direction in which the torque acts and the torque can be measured, there is no need to convert the force via a gear or the like, and even a minute torque can be used. It can be measured accurately. Further, the torque sensor 1 has a high linearity between the input torque and the output of the sensor because the strain gauge 14 is disposed on the flat surface portion 8 formed on the fixed end 6 (outer end) side. Since it is not necessary to make a significant correction in the processing circuit 200 of the torque measuring device 100, the torque can be measured with higher accuracy.

  Note that the torque sensor 1 used in the torque measuring instrument 100 of the present embodiment can change the magnitude of the restoring force generated by the deformation by changing the material, size, etc. used for the strain generating body 2. The possible torque range can be changed. For example, if a material having a large rigidity and hardly elastically deforms is used as the material of the strain generating body 2, a greater torque can be measured. Therefore, if a torque sensor having a material and shape corresponding to the torque measurement range is used within a range that can be stored in the torque measurement device 100, a single torque measurement device 100 can measure a wide range of torque from a minute torque. Is possible.

  Further, the torque sensor 1 used in the present torque measuring device 100 uses a strain generating body 2 that is formed in a (8, 10, 12) square shape having a plurality of plane portions, but is not limited thereto. It is not a thing. Since it is sufficient that the strain gauge 14 can be attached, it is only necessary to have one or more flat portions. For example, a circular shape (D-cut shape) in which a flat portion is formed on the fixed end 6 side may be used. As described above, it is preferable to form the plane portion on which the strain gauge 14 is arranged on the fixed end 6 side as much as possible so that the linearity between the input torque and the output of the torque sensor 1 is increased.

  Moreover, it is preferable that the chuck portion 102 of the torque measuring device 100 is configured to be detachable so that a chuck having an optimum diameter can be used according to the size of the measurement target. This is because if a chuck whose size does not match the size of the object to be measured is used, it may cause a shift in the rotational direction or slip, and accurate torque measurement cannot be performed. Further, the material of the chuck portion 102 may be changed according to the material to be measured. For example, when the measurement object is a resin, the measurement object may be damaged if the chuck portion 102 is a metal. Therefore, it is preferable to create a chuck portion 102 suitable for the material of the measurement object, and select and use the optimum chuck portion 102 according to the material of the measurement object. The structure of the chuck portion is not limited to this, and may be any shape that can be connected to the measurement object without being displaced in the rotation direction.

The (a) side view and (b) top view of the torque sensor 1 which consist of the strain body 2 and the strain gauge 14 used for the torque measuring device 100 of this embodiment. 1 is a cross-sectional view of a digital torque measuring device 100 according to the present embodiment. The figure which shows a mode that the processing circuit storage part 114 was changed from the closed state to the open state in the torque measuring device 100 shown in FIG. The top view of the torque measuring device 100 shown in FIG. The block diagram of the member which comprises the torque measuring device 100 of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque sensor 2 Strain body 4 Working end 6 Fixed end 8, 10, 12 Planar part 14 (14a-14d) Strain gauge 100 Torque measuring instrument 101 Torque measuring instrument main body 101a Grasp part 102 Chuck part 102a Claw part 104 Rotation connection Unit 106 bearing 108 pedestal unit 110 rotating shaft 112 fixed end fixed shaft 114 processing circuit storage unit 116 display unit 118 operation unit 120 hinge shaft 200 processing circuit 201 amplifying unit / filter unit 202 A / D conversion unit 203 CPU unit 204 applied voltage control Part

Claims (6)

Digital torque consisting of a torque measuring instrument body equipped with a torque sensor configured by placing a strain gauge on the surface of a strain generating body that is elastically deformed by an external force, and a mounting member attached to a measurement object A measuring instrument,
The torque measuring device main body includes a rotating shaft member that connects the mounting member to the torque measuring device main body so as to be relatively rotatable, a pedestal portion that stores the torque sensor, and a torque value from a signal output by the torque sensor. A processing circuit for calculating the torque value, and a digital display for displaying the torque value,
The torque sensor is formed of a band-shaped metal member having one end as a central end and the other end as an outer end, and forms a flat portion at an arbitrary position of the metal member, and has a spiral shape centering on the central end. The strain-generating body elastically deformed in the direction opposite to the direction of winding of the spiral and the opposite direction, and a strain gauge disposed on one or both surfaces of the plane portion of the strain-generating body, In the pedestal portion, the center end is fixed to the rotating shaft member, and the outer end is fixed to the pedestal portion of the torque measuring device main body, and is stored in a floating state.
The torque sensor is elastically deformed around the center end by fixing the attachment member to the measurement object and rotating the torque measuring device main body relative to the measurement object via the rotating shaft member. A digital torque measuring device characterized by measuring torque. The digital torque measuring device according to claim 1 , wherein the strain body is formed in a single spiral shape with the center end as a center. The planar portion, a digital torque measuring instrument according to claim 1 or 2, characterized in that the flat portion of the strain generating body is formed on most the outer end side can be formed. The strain body is formed in a rounded polygonal shape having a plurality of the flat portions,
The strain gauge is a digital torque measuring instrument according to claim 1 or 2, characterized in that it is arranged in a plane portion which most the outer end side formed of the plurality of flat portions. The digital display unit is disposed on an upper surface of the torque measuring device main body, the display unit of claims 1 to 4, characterized in that it is installed openably by a hinge member to the torque measuring device main body The digital torque measuring instrument according to any one of the above. The torque measuring device main body and a digital torque measuring instrument according to claim 1, any one of 5, characterized in that it comprises a rotation restricting member for restricting the angle of relative rotation of the rotary shaft member in a predetermined angle .

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