JP3326429B2 - Human body vibration evaluation device and hand-held vibration tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human body vibration evaluation device for detecting, analyzing, and displaying vibration received by a human body, and a hand-held vibration tool.

[0002]

2. Description of the Related Art In a hand-held vibrating tool such as a chipping hammer, a grinder, an impact wrench or the like, vibration from a vibration source is transmitted to a user's hand and arm when the tool is used. In a car, a motorcycle, a train, and the like, vibration from a vibration source is transmitted to the whole body of the user. It is known that when such hand-arm vibration or whole-body vibration is excessively applied to a human body, various effects are exerted on its health and comfort. On the other hand, recently, there is a high awareness of the safety of products, and the safety of devices such as tools used by human beings is becoming a first requirement for product quality. Among them, the influence of vibration on the human body such as a worker is one of the most important matters, and a response at a work site or the like is required. Therefore, in recent years, the relationship between the amount of vibration exposure and the effect on the human body has been actively studied. It is also known that if the amount of vibration exposure is limited to a predetermined value or less, the health of the user of the hand-held vibration tool can be sufficiently maintained.
Therefore, ISO (International Organization for Standardization), the Japan Society for Occupational Health, and the like have created standards for vibration measurement and vibration evaluation, and have created guidelines for hand-arm vibration. Then, based on such standards and guidelines, it has been attempted to ensure the health and safety of users of the vibration tool.

[0003]

However, even if the above-mentioned standards and guidelines are used, it is possible to evaluate how much the worker or the like has received the vibration exposure only when a certain work is continuously performed. Did not. Therefore, it is not always sufficient to accurately understand the amount of vibration exposure up to the present time received by an operator or the like in an actual operation in which the content of the operation or the like fluctuates variously even within one day. I couldn't say. For this reason, it must be said that the exact time was not sufficiently grasped as to how much work and the like can be continuously performed.

[0004] In view of the above, the present invention provides a demand for accurately evaluating vibration applied to a human body in actual work or the like, and for reliably protecting the human body from vibration applied to the human body. It was made in order to respond to.

[0005]

Accordingly, a human body vibration evaluating apparatus according to the present invention comprises a vibration detecting means for detecting a vibration to be added to a human body and a signal based on a signal detected by the vibration detecting means. Analysis means 20 for performing analysis based on the analysis result grasped by the analysis means 20, and the display means 11 for performing display based on the analysis result obtained by the analysis means 20. Every time is interrupted, the frequency load vibration acceleration effective value a _{hw of the} vibration continuously detected is grasped, and when the vibration is assumed to be continued, the 8-hour equivalent acceleration value a _{hw (eq, 8h)} There the limit time t _g as a predetermined reference value to ascertain using the frequency load vibration acceleration effective value a _hw, from the limit time t _g,
Subtracting the total time, from which the vibration by the vibration detecting means 13 so far is detected in one day, thereby is characterized by grasping the residual surplus time t _p.

[0006] In the human body vibration evaluating apparatus of the first aspect, each continued vibration is interrupted, to grasp the continuous frequency load vibration acceleration effective value a _hw of the vibration, the frequency load vibration acceleration effective value a _hw 8 hours equivalent acceleration value a
_The limit time t _{g at} which _{hw (eq, 8h)} becomes a predetermined reference value is grasped,
We know the residual surplus time t _p with the limit time t _g. Therefore, even if the content of work etc. fluctuates variously in one day, it is possible to accurately evaluate the vibration applied to the human body and to accurately grasp how much work etc. can be subsequently performed. Become.

[0007] human body vibration evaluating apparatus according to claim 2 is characterized in that a mountable to the apparatus for vibrating a human body such as an automobile or a hand-held oscillating tool.

[0008] In the human body vibration evaluating apparatus of the second aspect, the apparatus for vibrating a human body such as an automobile or a hand-held oscillating tool, it is possible to reliably protect the human body from the vibration applied to the human body.

Furthermore holding vibration tool according to claim 3 is characterized in that it comprises an human vibration test apparatus in claim 2.

According to the hand-held vibrating tool of claim 3 ,
In the actual work, the worker himself / herself can easily grasp the accurate evaluation of the vibration applied to the worker so far.

According to a fourth aspect of the present invention, the vibration detecting means is provided on the handle portion.

In the hand-held vibration tool according to the fourth aspect, it is possible to evaluate vibration more accurately.

According to a fifth aspect of the present invention, there is provided a hand-held vibration tool, wherein the above-mentioned human body vibration evaluation device is provided on the handle portion 2.

According to the hand-held vibrating tool of the fifth aspect , the portion which was originally an empty space is effectively used, so that the tool can be made more compact.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the human body vibration evaluation apparatus and the hand-held vibration tool according to the present invention will be described in detail with reference to the drawings.

FIG. 2 is a perspective view showing an angle grinder 1 which is a kind of the hand-held vibration tool. The angle grinder 1 includes a drive mechanism housing section 3 that houses an air motor and the like and has a bent shape,
It comprises a handle portion 2 for the operator to grip and a hose connection portion 5 for connecting an air hose. FIG. 1 is a sectional view showing the inside of the handle portion 2 of the angle grinder 1. Inside the handle portion 2, a three-axis vibration acceleration pickup 13, which will be described later, a control board 12 on which a microcomputer 20 (see FIG. 3) is mounted, a display portion 11 using, for example, a liquid crystal display element, 14 that supplies power to
And are provided. At the base end of the handle portion 2, a joint 16 for the drive mechanism housing portion 3 is provided, and further, an anti-vibration rubber 15 is provided to reduce vibration transmitted from the drive mechanism housing portion 3 to the handle portion 2. I have.

FIG. 3 is a block diagram showing a system for ascertaining the amount of vibration exposure of the worker and performing a display based on the amount of vibration exposure. This system corresponds to a human body vibration evaluation device, and is provided in the handle portion 2 of the angle grinder 1 as described above. The vibration transmitted from the drive mechanism storage unit 3 to the handle unit 2
The shaft vibration acceleration pickup (vibration detecting means) 13 detects the vibration. This three-axis vibration acceleration pickup 13
Is a device that generates, for example, electric charges proportional to the acceleration received by a piezoelectric element, and is capable of simultaneously measuring vibration accelerations in three axes (x, y, z) directions orthogonal to each other. . The signal detected by the three-axis vibration acceleration pickup 13 is input to an amplifier 17 for amplification, and further input to an anti-aliasing filter 18. This anti-aliasing filter 18
This is a low-pass filter for preventing aliasing noise from occurring at the time of / D conversion and using a cutoff frequency of about １ ／ of a sampling frequency at the time of performing A / D conversion. Then, the signal filtered by the anti-aliasing filter 18 is input to an A / D converter 19 next. The A / D converter 19 converts an input analog signal into a 16-bit digital signal at a sampling frequency of about 4 KHz to 5 KHz. The amplifier 17, the anti-aliasing filter 18 and the A / D converter 19 are constituted by 3 channels corresponding to the signals in the x, y and z directions outputted from the triaxial vibration acceleration pickup 13. Therefore, the A / D converter 19 outputs three types of vibration acceleration amplitude signals corresponding to the x, y, and z directions as digital signals. All of these digital signals are input to the microcomputer 20 and analyzed and processed by the microcomputer 20 functioning as an analyzing means, and the result is sent to the display unit (display means) 11 for display. Has become.

FIG. 5 is a flowchart for explaining the analysis procedure by the microcomputer 20.
First, in step S1, the digital signal is input via an input interface. And in step S2,
A frequency weighting process is performed on the input digital signal. In this frequency weighting process, specifically, the microcomputer 20 forms a digital filter having a frequency characteristic conforming to the standard of ISO5349 as shown in FIG. 6, and performs filtering by this digital filter. Here, each signal obtained by such a frequency weighting process is referred to as _xx (i), _xy (i), _xz
(I). In the next step S3, the work continuation time T
To determine the effective value of the frequency load vibration acceleration a _hw at
For that purpose, first, the frequency load vibration acceleration effective values a _hwx , a _hwy , and a _hwz for each axis are _obtained . This is specifically described by a _hwx as follows.

(Equation 1) Is calculated. Here, N is the total number of samplings during time T. From these values obtained for each axis, the effective frequency load vibration acceleration value a _hw for the three axes is obtained by the following equation: a _hw = (a _hwx ² + a _hwy ² + a _hwz ² ) ^1/2 . Then, in step S4, an 8-hour equivalent acceleration value a _{hw (eq, 8h)} is calculated using the effective frequency load vibration acceleration value a _hw . More specifically, the following equation is calculated: a _{hw (eq, 8h)} = a _hw [T / T ₍₈₎ ] ^1/2 . Here, T ₍₈₎ is 8 hours.

According to the standard of ISO5349 and the guideline of the Japan Society for Occupational Health, the 8-hour equivalent acceleration value a
Working standards are determined based on _{hw (eq, 8h)} . That is, this 8-hour equivalent acceleration value a _{hw (eq, 8h)} is 2.5 (I
(SO5349) or 2.26 (Guidelines of the Japan Society for Occupational Health), it means that the onset of vibration disease after 8 to 10 years can be suppressed to 10% or less. Therefore, as shown in FIG. 4, when the work continued for the time t ₁ is completed as shown in FIG. 4, that is, when the vibration detected by the three-axis vibration acceleration pickup 13 is stopped, _The frequency load vibration acceleration effective value a _hw1 is calculated for the vibration during _{1 and} the 8-hour equivalent acceleration value a _{hw (eq, 8h)} is calculated from this a _hw1 . Next, _assuming that the guidelines of the Japan Society for Occupational Health are to be followed, from the following equation a _{hw (eq, 8h)} = a _hw1 (t / T ₍₈₎ ) ^1/2 ≦ 2.26, The limit time t = t _{g at} which the time equivalent acceleration value a _{hw (eq, 8h)} becomes 2.26 can be calculated. Then by subtracting the operation time t ₁ from the limit time t _g determined, it is possible to obtain the residual surplus time t _p1. That is, even if the same work is continued for another time _tp1 on that day, the onset probability of the oscillating disease after 8 to 10 years can be suppressed to 10% or less. Therefore, the display section 11 shows FIG.
As shown in, for displaying the value of the 8-hour equivalent acceleration value a _{hw (eq, 8h),} and actual operation time t ₁ to the present time, and the residual surplus time t _p1.

Next, assuming that the work is continued for the time t ₂ and is completed, the effective frequency load vibration acceleration value a _hw2 for the vibration during the time t ₂ is calculated according to the above-described analysis procedure as shown in FIG. I do. And this a _hw2
By using the above-described a _hw1 and, 8-hour equivalent acceleration value a _{hw (eq, 8h)} at the work end with the following formula _{a hw (eq, 8h) =} a hw1 (t 1 / T (8)) 1 ^{/ 2} + a _hw2 (t ₂ / T ₍₈₎ ) ^1/2 That is, the 8-hour equivalent acceleration value a _{hw (eq, 8h)} for the work during the time t ₁ and the 8-hour equivalent acceleration value a for the work during the time t _{2
hw (eq, 8h)} . on the other hand,
_Assuming that the work equivalent to the work during this time t ₂ is continuously performed, the following equation a _{hw (eq, 8h)} = a _hw2 (t / T ₍₈₎ ) ^1/2 ≦ 2.26 From this, the limit time t = t _{g at} which a _{hw (eq, 8h)} = 2.26 is obtained. The total working time t ₁ + t from this limit time t _g
2 is subtracted to obtain the remaining margin time _tp2 . Then, these results are displayed on the display unit 11 in the same manner as described above.
Further, the above procedure is repeated each time the operation continues at times t ₃ and t ₄ . When the remaining margin time t _pi falls below a predetermined value of, for example, about 30 minutes, a predetermined warning is displayed on the warning display unit 21 provided in the display unit 11.

The hand-held vibration tool constructed and operated as described above is a vibration acceleration pickup 13 for detecting vibration.
And a microcomputer 20 for calculating an 8-hour equivalent acceleration value a _{hw (eq, 8h)} as a vibration exposure amount based on the detected signal, and a display unit 11 for displaying the microcomputer 20. I have. The human body vibration evaluation device calculates an 8-hour equivalent acceleration value a _{hw (eq, 8h)} for each continuous work every time the work is interrupted, and accumulatively adds the calculated values within one day to obtain a total of 8 hours. Equivalent acceleration value a
_{hw (eq, 8h)} is _calculated . Therefore, even in the actual work in which the contents of the work are variously varied, the worker himself / herself can know exactly how much vibration has been exposed. Therefore, the protection of the worker's body can be ensured. In addition, every time the continued work is interrupted, it is assumed that the same work as the work performed immediately before is continuously performed, and the eight-hour equivalent acceleration value a _{hw (eq, 8h)} is grasped.
From the eight-hour equivalent acceleration value a _{hw (eq, 8h)} , the remaining margin time t _pi is obtained and displayed. Therefore, even in an actual operation in which the contents of the operation vary variously, the remaining margin time t _pi can be accurately obtained, and the body protection of the tool user can be further ensured.

Further, a three-axis vibration acceleration pickup 13,
The battery 14, the control board 12, and the display unit 11 are provided in the handle unit 2. Therefore, not only can the three-axis vibration acceleration pickup 13 accurately detect vibrations, but also the size of the tool can be reduced by effectively using the previously empty space.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. In the above, the remaining margin time t _{pi is} calculated from a _{hw (eq, 8h)} ≦ 2.26 according to the guidelines of the Japan Society for Occupational Health.
Was obtained, but a _{hw (eq,}
It from _8h) ≦ 2.5 may be obtained residual surplus time t _pi, further with a margin a _{hw (eq, 8h)} and the value of such ≦ 2.0 to obtain the residual surplus time t _pi Is also good. Further, since the layout and display contents of the display unit 11 shown in FIG. 7 are merely examples, it is needless to say that various changes can be made. In the above description, the case where the human body vibration evaluation device is mounted on the angle grinder 1 as an example of the hand-held vibration tool has been described. However, an impact wrench, a ratchet wrench, a driver, other types of grinders, hammers,
By applying the present invention to various hand-held vibrating tools such as a chain saw, excellent effects can be obtained.

Further, the human body vibration evaluation device of the present invention can be mounted on all devices for applying vibration to a human body such as an automobile. In the case of a hand-held vibrating tool, hand-arm vibration is a problem, but in the case of a car, motorcycle, train, etc., whole-body vibration is a problem. The standard for the whole body vibration is defined in ISO2631. Therefore, in this case, the digital filter for performing the frequency load processing is configured to have the frequency characteristics shown in FIG. 8, and the 8-hour equivalent acceleration value a _{hw (eq, 8h)} calculated by the same procedure as above is about 0.5. The remaining margin time t _pi is calculated by using the limit time t _g when it becomes 5. Then, the three-axis vibration acceleration pickup 13, the control board 12, the display unit 11, the battery 14 (which may be provided in advance) and the like are provided in the above-mentioned automobile or the like. At this time, the three-axis vibration acceleration pickup 13
Is provided in the seat of an automobile, etc., vibration can be detected accurately. Also, an 8-hour equivalent acceleration value a _{hw (eq, 8h)} and a remaining margin time t _pi are calculated by the same procedure as when the three-axis vibration acceleration pickup 13 is provided on the handle of an automobile or motorcycle and mounted on the hand-held vibration tool. May be displayed.

[0025]

In the human body vibration evaluating apparatus according to claim 1 according to the present invention, for each continued vibration is interrupted, grasps the frequency load vibration acceleration effective value of continued vibration, with the frequency load vibration acceleration effective value 8 The limit time at which the time equivalent acceleration value becomes a predetermined reference value is grasped, and the remaining margin time is grasped using this limit time. Therefore, even if the content of work etc. fluctuates variously in one day, it is possible to accurately evaluate the vibration applied to the human body and to accurately grasp how much work etc. can be subsequently performed. Become.

[0026] In the human body vibration evaluating apparatus according to claim 2 is the device for vibrating a human body such as an automobile or a hand-held oscillating tool, it is possible to reliably protect the human body from the vibration applied to the human body.

Further , according to the hand-held vibrating tool of the third aspect , it is possible for the operator to easily grasp the accurate evaluation of the vibration applied to the operator up to the present time in the actual work.

According to the hand-held vibrating tool of the fourth aspect , it is possible to evaluate vibration more accurately.

According to the hand-held vibrating tool of the fifth aspect , the portion which was originally an empty space is effectively used, so that the size of the tool can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the inside of a handle portion of an angle grinder according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the angle grinder.

FIG. 3 is a block diagram showing a human body vibration evaluation device mounted on the angle grinder.

FIG. 4 is an explanatory diagram showing a calculation state of a frequency load vibration acceleration effective value performed by a microcomputer constituting the human body vibration evaluation device.

FIG. 5 is a flowchart showing an analysis procedure performed by the microcomputer.

FIG. 6 is a frequency characteristic diagram of a digital filter formed by the microcomputer.

FIG. 7 is a schematic plan view showing a display unit constituting the human body vibration evaluation device.

FIG. 8 is a frequency characteristic diagram of a digital filter formed by a microcomputer of the human body vibration evaluation apparatus when the apparatus is provided in an automobile or the like in which whole body vibration is a problem.

[Explanation of symbols]

 2 Handle section 11 Display section 13 3-axis vibration acceleration pickup 20 Microcomputer

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Claims (5)

(57) [Claims] A vibration detecting means (13) for detecting a vibration to be applied to a human body, and the vibration detecting means (1).
(3) An analysis means (20) for performing an analysis based on the signal detected in (3), and a display means (11) for displaying based on the analysis result grasped by the analysis means (20). Each time the vibration continuously detected by the vibration detecting means (13) is interrupted, the frequency load vibration acceleration effective value (a) of the continuously detected vibration is calculated.
_hw ), and if it is assumed that the above vibrations continue, 8
Grasp time equivalent acceleration values _{(a hw (eq, 8h)} ) is a limit time which is a predetermined reference value (t _g) using the frequency load vibration acceleration effective value of (a _hw), the limit time (t _g ),
A human body vibration evaluation characterized in that the total time during which vibration is detected by the vibration detecting means (13) up to the present time in a day is subtracted, and the remaining time to spare (t _p ) is thereby obtained. apparatus. 2. The human body vibration evaluation device according to claim 1, wherein the human body vibration evaluation device can be mounted on a device that applies vibration to a human body, such as an automobile or a hand-held vibration tool. 3. A hand-held vibration tool comprising the human body vibration evaluation device according to claim 2 . 4. A hand-held vibration tool according to claim 3 , wherein said vibration detecting means is provided on a handle portion. 5. The hand-held vibration tool according to claim 3 , wherein said human body vibration evaluation device is provided on a handle portion (2).