JP2010052065A - Impact rotary tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact rotary tool improved in the determination accuracy of a maintenance period. <P>SOLUTION: In the impact rotary tool 1 having an impact mechanism 2 for impulsively transmitting the rotating drive of a motor 3 to an output shaft 5 by striking operation, the impact rotary tool is provided with a strike detecting means 7 for detecting a strike by the striking operation, a strike speed detecting means 8 for calculating striking speed by the strike that the strike detecting means 7 detects, and a control means 9 for determining the maintenance period of the impact rotary tool 1 by comparing the striking speed that the strike speed detecting means 8 calculates with a reference value, so that the maintenance period based on the wearing state of the impact mechanism 2 is determined and the determination accuracy of the maintenance period is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an impact rotary tool that performs a tightening operation using an impact impact such as an impact driver or an impact wrench.

  2. Description of the Related Art Conventionally, there is an impact rotary tool provided with an impact mechanism that repeatedly engages a hammer driven to rotate by a motor and an anvil provided on an output shaft, and transmits the rotation to the output shaft.

  The impact rotary tool is widely used in construction sites and assembly factories because of its high workability of high rotation and high torque.

  However, since the above engagement is repeated impactively, there is a problem in that metal wear occurs in the impact mechanism, the transmission of impact energy is reduced, and the tightening torque is reduced.

  Therefore, there is one that determines the maintenance timing of the impact mechanism based on the number of times of operation of the main switch of the impact rotary tool and the motor operating time (see, for example, Patent Document 1).

However, since the load varies depending on the work content, the wear state of the impact mechanism cannot be grasped at the number of operations and the operation time, and there is a problem that the determination accuracy of the maintenance time is low.
JP 2002-018744 A

  Therefore, the present invention provides an impact rotary tool that grasps the wear state of an impact mechanism that causes a decrease in tightening torque and determines the maintenance time from the wear state.

  In order to solve the above-mentioned problem, the impact rotary tool 1 of the present invention transmits to the output shaft 5 an impact by an output shaft 5 that attaches a member to be fastened to the target member and a hammer 22 that is rotationally driven by the motor 3. In the impact rotary tool 1 provided with the impact mechanism 2 and the motor control means 6 for controlling the rotation and stop of the motor 3, the impact detection means 7 for detecting the impact by the impact mechanism 2, and the impact detection means The impact speed detection means 8 for calculating the impact speed from the detected hitting interval 7 is provided, and the impact rotation is calculated by comparing the impact speed calculated by the impact speed detection means 8 with a set reference value. A control means 9 for determining the maintenance time of the tool 1 is provided.

  With such a configuration, the wear state of the impact mechanism 2 can be grasped from a comparison between the impact speed affected by the wear of the impact mechanism 2 and the reference value.

  Then, a rotation angle detection means 10 for detecting the rotation angle of the motor 3 is provided, and the control means 9 determines the correctness of the hit detected by the hit detection means 7 from the rotation angle detected by the rotation angle detection means 10. Thus, even if the hit detection means 7 mistakenly detects an impact without a hitting action as a hit, the hit detection means erroneously detects the hit used by the hit speed detection means 8 for calculation by the rotation angle detection means 10. Thus, it is possible to eliminate the hitting without the hitting action detected.

  Further, seating detection means 11 for detecting that the tightened member is seated on the target member is provided, and the hitting speed detection means 8 calculates the hitting speed from the hit after the seating detection by the seating detection means 11. Thus, the striking speed can be calculated from the striking motion that the striking speed detecting means 8 stably repeats after sitting.

  Further, a hitting number setting means 12 for stopping the motor 3 when the hitting number is counted and set is provided, and hitting immediately before the hitting speed detecting means 8 reaches the hitting number set by the hitting number setting means 12. By calculating the striking speed from the above, the striking speed detecting means 8 can calculate the striking speed from the stable striking motion just before the completion of the work.

  Furthermore, by providing the notification means 14 for notifying the judgment result of the control means 9, it can be notified that the impact rotary tool 1 has reached the maintenance time.

  Further, when the control means 9 determines that the impact rotary tool 1 is in a maintenance period, by providing the operation prohibiting means 15 for prohibiting the operation of the impact rotary tool 1, the impact mechanism 2 is worn and the tightening torque is reduced. Can be prohibited.

  Further, by allowing the reference value that the control means 9 determines to be the maintenance time to be changed by the reference value setting changing means 13, the allowable range of the tightening torque that decreases due to wear of the impact mechanism 2 can be changed and adjusted.

  According to the present invention, by grasping the wear state of the impact mechanism as described above, the maintenance time based on the wear state of the impact mechanism can be determined, and the determination accuracy of the maintenance time is improved.

  Further, by eliminating the hitting that does not involve the hitting operation from the hitting used for calculating the hitting speed, the hitting speed calculation accuracy is increased, and the maintenance time determination accuracy is improved.

  Furthermore, by calculating the hitting speed from the stable hitting action after sitting, the hitting speed calculation accuracy increases, and the maintenance timing judgment accuracy improves.

  Furthermore, by calculating the hitting speed from the stable hitting operation just before the completion of the work, the hitting speed calculation accuracy is increased, and the determination accuracy of the maintenance time is improved.

  Furthermore, since the maintenance time can be notified, the operator can easily detect the maintenance time.

  Further, since the impact mechanism is worn and the operation in a state where the tightening torque is reduced is prohibited, the occurrence of the tightening failure is prevented.

  Further, since the allowable range of the tightening torque can be changed, it becomes easy to manage the tightening torque according to the work content.

  Hereinafter, the present invention will be described based on each embodiment shown in the accompanying drawings.

  FIG. 1 is a block diagram of a first embodiment of an impact rotary tool 1 according to the present invention.

  The impact rotary tool 1 includes an output shaft 5 that attaches a member to be tightened (not shown) to a target member (not shown), a motor 3 that rotationally drives, and a speed reducer 4 that decelerates the rotational drive of the motor 3. The impact mechanism 2 transmits the decelerated rotational drive to the output shaft 5 by a striking operation, and the motor control means 6 controls the rotation and stop of the motor 3.

  As shown in FIG. 2, the impact mechanism 2 is rotationally driven by being engaged with the drive shaft 21 for transmitting the rotational force from the speed reducer 4, the hammer 22 fitted to the drive shaft 21, and the hammer 22. An anvil 23, a cam mechanism (not shown) that retracts the hammer 22 engaged with the anvil 23 with a striking operation, and a retracted hammer 22 again with the anvil 23 with a striking operation. The anvil 23 is provided integrally with the output shaft 5.

  The operation of the impact mechanism 2 will be described with reference to FIG. When the motor 3 is driven to rotate, the hammer 22 and the anvil 23 collide as shown in FIG. At this time, if the load applied to the output shaft 5 from the tightened member is small, the hammer 22 and the anvil 23 rotate while being engaged.

  However, if the load applied to the output shaft 5 is large, the collision between the hammer 22 and the anvil 23 becomes a striking action as shown in FIG. 3B, and the hammer 22 rotates the anvil 23 by a predetermined angle, and then springs. It rotates while retreating to the motor 3 side by the cam mechanism against the urging of 24, and gets over the anvil 23 as shown in FIG.

  When the motor 3 is further driven to rotate, the hammer 22 advances from the motor 3 side by the urging of the spring 24 to be in the state of FIG. 3A, and thereafter the above operation is repeated by the rotation driving of the motor 3.

  Further, in order to determine the maintenance time in accordance with the wear state of the impact mechanism 2, the impact detection means 7 for detecting the impact of the impact operation in the impact mechanism 2 and the interval at which the impact detection means 7 detects the impact. The impact rotating tool 1 is provided with an impact speed detecting means 8 for calculating the impact speed from the above and a control means 9 for determining the maintenance time of the impact rotating tool 1 from the impact speed calculated by the impact speed detecting means 8. .

  The hit detection means 7 is, for example, an impact sensor, and detects an impact generated by the impact operation of the impact mechanism 2 as an impact.

  Therefore, the impact detection means 7 does not generate an impact when the hammer 22 and the anvil 23 rotate together with a small load, so that the collision of the hammer 22 and the anvil 23 is not detected as an impact, and the hammer 22 that has collided with a large load is detected. Since an impact is generated in the state of getting over the anvil 23, a collision between the hammer 22 and the anvil 23 is detected as a hit.

  The hitting speed detecting means 8 calculates the hitting speed from the average time every predetermined number of hitting periods, for example, every four times, with the hitting detection means 7 detecting the hitting interval as the hitting period. .

  Further, the control means 9 determines that it is the maintenance time when the hitting speed calculated by the hitting speed detecting means 8 is the same as or faster than the reference value.

  In addition, the hammer collision surface 25 and the anvil collision surface 26 with which the hammer 22 and the anvil 23 collide with each other form a surface substantially perpendicular to the rotation axis as shown in FIG. As shown in FIG. 4, the respective collision surfaces 25 and 26 are inclined along the rotation direction.

  And if each collision surface 25 and 26 inclines, the collision force by striking operation will reduce, and the energy transmitted to the output shaft 5 will also fall. Therefore, as shown in FIG. 5, the relationship between the wear amount of the impact mechanism 2 (shown as hammer and anvil wear amount in the drawing) and the tightening torque generated from the output shaft 5 to the tightened member is as follows. The tightening torque decreases with wear.

  Further, since the reduction of the collision force reduces the amount of retraction of the hammer 22 toward the motor 3 by the striking operation, the relationship between the wear amount of the impact mechanism 2 and the striking cycle is as shown in FIG. Along with this, the hitting cycle becomes faster.

  Further, when the impact mechanism 2 is worn, the hitting cycle, which is the movement time at the hitting speed, becomes fast. Therefore, the relationship between the wear amount of the impact mechanism 2 and the hitting speed becomes faster as the impact mechanism 2 is worn as shown in FIG. Is.

  Therefore, the maintenance time when the tightening torque is reduced is a state in which the impact mechanism 2 is worn and the hitting speed is increased, and the hitting speed is a reference for comparison with the hitting speed calculated by the hitting speed detecting means 8. Value.

  Hereinafter, although other embodiment is shown, description is abbreviate | omitted by allocating the same code | symbol to the same structure.

  FIG. 8 shows a configuration diagram of the second embodiment. This is because the rotation angle detection means 10 for detecting the rotation angle of the motor 3 is provided in the first embodiment, and the control means 9 determines whether or not the hit is correct based on the rotation angle of the motor 3 as the detection condition of the hit cycle for calculating the hitting speed. Is what you do.

  The rotation angle detection means 10 detects the rotation angle of the motor 3 for each impact detected by the impact detection means 7. For example, a rotation sensor such as a frequency generator is used for a brush motor, and a Hall element is used for a brassless motor. A position detection sensor such as is desirable.

  Even if the hit detection means 7 mistakenly recognizes an impact without a hitting action as a hit, the control means 9 determines whether the detected hit is correct from the amount of change in the rotation angle of the motor 3 detected by the rotation angle detection means 10. Then, the hitting cycle by the hit detected in error is eliminated by setting the hit without changing the rotation angle as the impact without the hitting operation.

  Therefore, by determining whether or not the batting is correct from the rotation angle detected by the rotation angle detecting means 10, the striking speed detecting means 8 can calculate the striking speed from the striking cycle accompanied by the striking operation, and the impact mechanism 2 is worn. The state is correctly grasped, and the determination accuracy of the maintenance time of the control means 9 is improved.

  FIG. 9 shows a configuration diagram of the third embodiment. In this embodiment, the seating detection means 11 is provided in the second embodiment, and the hitting speed is calculated from the hit after the seating is detected.

The seating detection means 11 detects the seating when the member to be fastened is seated on the target member. As the seating detection means 11, for example fastening estimates the torque T tightening in the work, estimated torque T is predetermined tightening torque (hereinafter, the seating torque T _s wherein) when it becomes more than or the same value, the clamping It is determined that the attached member is seated.

  In the method of estimating the tightening torque T, the balance of the kinetic energy of one stroke, that is, the energy that the hammer 22 strikes on the anvil 23 of the output shaft 5 is substantially equal to the energy consumed by the tightening. It is derived from the relationship.

  The tightening torque T and the rotation angle θ of the member to be tightened with the impact rotary tool 1 can be expressed by a function T = τ (θ) as shown in FIG.

  The rotation angle θ is also the rotation angle of the anvil 23 at the time of each hit (the rotation angle of the output shaft 5). For example, when the hammer 22 performs two hitting operations each time the hammer 22 rotates once, This is obtained by subtracting the motor rotation amount necessary for the output shaft 5 to make a half rotation based on the reduction ratio from the motor rotation amount between hits. The motor rotation amount is preferably obtained by the rotation angle detection means 10.

Θ _{1 ...} θ _n in the figure, the function τ interval [theta _1, theta _2] The integrated value E ₁ in a tightened energy consumed in the work, the striking generated by the theta ₁ point anvil 23 Equal to the given energy.

Therefore, the average torque <T _n > in the section [θ _n , θ _{n + 1} ] is given by the energy E _n and the rotation angle Θ _n = (θ _{n + 1} −θ _n ) of the output shaft 5 that has changed between strokes.
<T _n > = E _n / Θ _n (1)
It can be asked.

The energy E _n is calculated by the average rotation speed <S _n > of the anvil 23 between hits obtained by dividing the rotation angle Θ _n by the hit period and the inertia moment Ja of the known anvil 23.
E _n = 1/2 × Ja × <S _n > ² (2)
It can be asked.

Note that the estimated torque T tightening use in seating detection is the average torque <T _n>, it is determined that <T _n> is that to reach the seating torque T _s, the seating detection means 11 is seated Is.

  In addition, the load before seating varies greatly depending on the shape and type of the target member and the tightening member. For example, the tightening member is long and penetrates the target member before seating, and only the thread is cut to the seating. The hitting operation may become unstable, for example, no movement occurs. However, after the seating, a high load is generated by tightening, so that the hitting operation is stably repeated.

  Therefore, after the seating, the load is stabilized and the hitting operation is surely repeated. Therefore, the hitting speed can be calculated with high accuracy, and the determination accuracy of the maintenance time is improved.

  FIG. 11 shows a block diagram of the fourth embodiment. This is because, in the third embodiment, the number of hits of the impact mechanism 2 is counted and the hit number setting means 12 for stopping the hit operation when the hit number is reached, and the reference value for adjusting and changing the judgment criteria of the control means 9 A setting change means 13, an informing means 14 for notifying the operator of the maintenance time, and an operation prohibiting means 15 for prohibiting the operation of the impact rotary tool 1 determined to be the maintenance time are provided, and the number of hits is detected after the seating is detected. It is what begins to count.

  When the seating detection means 11 detects the seating of the tightened member, the hitting number setting means 12 counts the subsequent hits, and when the hitting number set by the hitting number setting means 12 is reached, the motor 3 is stopped. The work is completed.

  Then, the hitting speed detecting means 8 hits from the hitting cycle of hitting immediately before reaching the hitting number set by the hitting number setting means 12, for example, hitting from four times before the set hitting number to the hitting number set. By calculating the speed, the striking speed in a stable load state in the tightening work immediately before the completion of the work is calculated.

  Therefore, the hitting speed is obtained by suppressing an error caused by the fluctuation of the load, the accuracy of the estimated wear state of the impact mechanism 2 is increased, and the determination accuracy of the maintenance time is improved.

  In addition, if the load is substantially stable from the beginning of work to the end of work such as wood screws and bolts and nuts and performs a constant hitting operation, the hit number setting means 12 is provided in the first or second embodiment to start the work. It is also possible to calculate the hitting speed immediately before the completion of work by counting the number of hits from time.

  Further, the reference value, which is the judgment criterion of the control means 9, can be changed and adjusted by the reference value setting changing means 13 in accordance with the allowable lowering range of the tightening torque for each work, so that the safety value is included in the reference value. An impact speed that is slower than the impact speed at the lower limit of the allowable range of the tightening torque may be used as the reference value.

  The notification means 14 is a marker, for example, and lights up when the control means 9 determines that the maintenance time is reached, thereby notifying the operator that the maintenance time is reached and notifying the operator.

  In addition, the said alerting | reporting means 14 may notify by an audio | voice, and what combined them, and should just be able to alert | report a maintenance time to an operator.

  The operation prohibiting means 15 operates the operation switch (not shown in particular) for stopping the operation of the impact rotary tool 1 and operating the impact rotary tool 1 when the control means 9 determines that the maintenance time is reached. Is not operated, and the occurrence of poor tightening by the impact rotary tool 1 in a state in which the tightening torque is reduced is prevented.

It is a block diagram of 1st embodiment of the impact rotary tool of this invention. It is a perspective view of an impact mechanism same as the above. It is an operation diagram of the impact mechanism same as above, (a) is a state where the hammer collides with the anvil, (b) is a state where the anvil is rotated by the hammer, (c) is a state where the hammer has passed over the anvil. is there. It is a perspective view of the abrasion state of an impact mechanism same as the above. It is a related figure of the amount of hammer and anvil wear and tightening torque same as the above. It is a related figure of a hammer and anvil wear amount, and a hitting cycle same as the above. It is a related figure of hammer and anvil wear amount and hitting speed same as above. It is a block diagram of 2nd embodiment same as the above. It is a block diagram of 3rd embodiment same as the above. It is a related figure of the rotation angle of a to-be-clamped member same as the above, and fastening torque. It is a block diagram of 4th embodiment same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Impact rotary tool 2 Impact mechanism 3 Motor 4 Reduction gear 5 Output shaft 6 Motor control means 7 Impact detection means 8 Impact speed detection means 9 Control means 10 Rotation angle detection means 11 Seating detection means 12 Stroke number setting means 13 Reference value setting change Means 14 Notification means 15 Operation prohibition means 22 Hammer 23 Anvil

Claims (7)

  An output shaft for attaching the member to be tightened to the target member, an impact mechanism for transmitting a hammer hitting rotation by a motor to the output shaft, and motor control means for controlling rotation and stop of the motor are provided. In the impact rotating tool, the impact detecting means for detecting the impact by the impact mechanism, the impact speed detecting means for calculating the impact speed from the impact interval detected by the impact detecting means, and the impact speed detecting means An impact rotary tool comprising a control means for judging a maintenance timing of the impact rotary tool by comparing the calculated hitting speed with a predetermined reference value set.   The rotation angle detection means for detecting the rotation angle of the motor is provided, and the control means determines the correctness of the hit detected by the hit detection means from the rotation angle detected by the rotation angle detection means. The impact rotary tool according to 1.   Seating detection means for detecting that the tightened member is seated on the target member is provided, and the hitting speed detection means calculates the hitting speed from the hit after the seating detection by the seating detection means. Item 3. The impact rotary tool according to Item 1 or 2.   When the number of hits reaches the set number of hits, there is provided a hit number setting means for stopping the motor, and the hit speed is calculated from the hit immediately before the hit speed detection means reaches the hit number set by the hit number setting means. The impact rotary tool according to any one of claims 1 to 3, wherein:   The impact rotary tool according to any one of claims 1 to 4, further comprising a notification unit that notifies a determination result of the control unit.   6. The impact rotation according to claim 1, further comprising an operation prohibiting unit that prohibits the operation of the impact rotating tool when the control unit determines that the impact rotating tool is in a maintenance period. tool. The impact rotary tool according to any one of claims 1 to 6, wherein a reference value determined by the control means as a maintenance time can be changed by a reference value setting changing means.

Images