JP6664102B2 - How to set impact rotary tool and shut-off impact number - Google Patents

Description

  The present invention relates to an impact rotary tool for fastening a screw member such as a bolt or a nut by an intermittent rotational impact force.

  In a mechanical impact rotary tool, a hammer that rotates with a motor output hits an output shaft in a rotational direction, thereby generating an intermittent rotational impact force on the output shaft and tightening a screw member. An oil pulse tool, which is a type of impact rotary tool, generates an intermittent rotational impact force on an output shaft of a liner rotating at the output of a motor by generating a pressure difference between oil chambers, thereby tightening a screw member. Since the impact rotary tool is used in an assembly factory or the like, the tightening torque of the screw member needs to be accurately controlled to a value set by the user.

  In order to increase the control accuracy of the tightening torque, it is preferable to provide a torque measuring means on the output shaft and directly measure the actual tightening torque. However, there is a problem that the cost and size of the tool are increased. Therefore, conventionally, there has been provided an impact rotary tool having a shut-off function of automatically stopping the motor by estimating that the tightening torque has reached a set value. Patent Literature 1 discloses a method of counting the number of hits detected by the impact detecting means and the number of hits detected by the impact detecting means, which detects the impact by the impact mechanism. A mechanical impact rotary tool provided with control means for automatically stopping a motor is disclosed.

JP 2009-83038 A

  In the impact rotary tool, the correspondence between the tightening torque value and the number of impacts (impacts) for automatically stopping the motor (hereinafter, also referred to as “shut-off impact number”) is stored in a master table of a memory. . The manufacturer of the impact rotary tool actually creates a master table by measuring the number of shut-off impacts for realizing each of the plurality of tightening torque values using a predetermined screw member and a member to be fastened. Thus, the master table holds the number of shut-off impacts corresponding to each set value of the tightening torque. When the user sets a target tightening torque value, the impact rotary tool controls the motor rotation based on the number of shut-off impacts held in the master table.

  However, the screw member and the member to be fastened at the assembly factory or the like may be different from the screw member and the member to be fastened when the master table is created. For example, if the member to be fastened is softer than the member to be fastened when the master table was created, the impact rotating tool automatically stops the motor rotation at the shutoff impact number held on the master table, and the tightening torque value is reduced. The target value may not be reached. Conversely, if the member to be fastened is harder than the member to be fastened when the master table was created, the impact rotary tool automatically stops the motor rotation with the number of shut-off impacts held on the master table. The torque value may exceed the target value.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for appropriately setting the number of shut-off impacts.

  In order to solve the above problems, an impact rotary tool according to an aspect of the present invention includes an impact mechanism that generates an intermittent rotational impact force on an output shaft by a motor output, and a setting unit that sets a number of shut-off impacts of the impact mechanism. And a shock detector that detects the shock applied to the output shaft by the impact mechanism, and counts the number of shocks detected by the shock detector, and stops the motor rotation when the counted number of shocks reaches the number of shut-off shocks And a control unit for causing the control unit to perform the control. From the relationship between the target tightening torque value when the motor rotation is stopped at the number of shut-off impacts and the actual tightening torque value measured when the motor rotation is actually stopped at the number of shut-off impacts, The shut-off impact number is corrected so that the tightening torque value when the rotation is stopped becomes the target tightening torque value.

  Another embodiment of the present invention is a method for setting a shutoff impact number for automatically stopping motor rotation. This method sets the initial value of the number of shut-off shocks, and actually sets the target tightening torque value when the motor rotation is stopped at the initially set number of shut-off shocks and the actually set number of shut-off shocks. From the relationship with the actual tightening torque value measured when the motor rotation is stopped, the number of shut-off impacts at which the tightening torque value when the motor rotation is stopped becomes the target tightening torque value is determined.

  According to the present invention, it is possible to provide a technique for appropriately setting the number of shut-off impacts.

It is a figure showing composition of an impact rotary tool concerning an embodiment. FIG. 4 is a diagram illustrating a relationship between a target torque value and a number of shut-off impacts. FIG. 9 is a diagram illustrating a shut-off impact number corresponding to a predetermined target torque value. It is a figure showing the curve which expresses the relation between the target torque value and the number of shut-off impacts, and the estimated curve which expresses the relation between the actual fastening torque value and the impact number. It is a figure for explaining the number of impacts to obtain a predetermined tightening torque value. It is a figure showing the flow chart of the processing which corrects shutoff impact number.

  FIG. 1 shows a configuration of a mechanical impact rotary tool according to an embodiment of the present invention. In the impact rotary tool 1, power is supplied by a rechargeable battery built in a battery pack. The motor 2 as a drive source is driven by a motor drive unit 11, and the rotation output of the motor 2 is transmitted to the drive shaft 5 after being reduced in speed by a speed reducer 3. A hammer 6 is connected to the drive shaft 5 via a cam mechanism (not shown). The hammer 6 is urged by a spring 4 toward an anvil 7 having an output shaft 8.

  As long as no force equal to or greater than the predetermined value acts between the hammer 6 and the anvil 7, the hammer 6 and the anvil 7 are engaged in the rotational direction, and the hammer 6 transmits the rotation of the drive shaft 5 to the anvil 7. However, when a force equal to or more than a predetermined value acts between the hammer 6 and the anvil 7, the hammer 6 retreats against the spring 4 by the cam mechanism, and the engagement state between the hammer 6 and the anvil 7 is released. Thereafter, by the urging by the spring 4 and the guidance by the cam mechanism, the hammer 6 advances while rotating, and applies a rotational impact to the anvil 7. In the impact rotary tool 1, the spring 4, the drive shaft 5, the hammer 6, and the cam mechanism apply an impact to the anvil 7 and the output shaft 8 by a motor output to generate an intermittent rotational impact force on the output shaft 8. 9.

  In the impact rotary tool 1, the components such as the control unit 10 and the setting unit 15 are realized by a microcomputer mounted on a control board. The control unit 10 has a function of controlling the rotation of the motor 2. The operation switch 16 is a trigger switch operated by a user, and the control unit 10 controls on / off of the motor 2 by operating the operation switch 16, and outputs a drive instruction according to the operation amount of the operation switch 16 to the motor drive. To the unit 11. The motor drive unit 11 controls the voltage applied to the motor 2 according to a drive instruction supplied from the control unit 10 to adjust the motor rotation speed.

  The impact detector 12 detects an impact applied to the output shaft 8 by the impact mechanism 9. For example, the impact detection unit 12 may include an impact sensor that detects an impact caused by the hammer 6 hitting the anvil 7, and an amplifier that amplifies the output of the impact sensor and supplies the output to the control unit 10. For example, the shock sensor is a piezoelectric shock sensor that outputs a voltage signal corresponding to a shock, and the amplifier amplifies the output voltage signal and supplies the amplified voltage signal to the control unit 10. The impact detector 12 may adopt another configuration, and may be, for example, a sound sensor that detects an impact applied to the output shaft 8 by the impact mechanism 9 by detecting a striking sound.

  Before starting the work, the user sets a target tightening torque value (hereinafter, also simply referred to as a “target torque value”) according to the work target in the impact rotary tool 1. During the tightening operation, the impact rotary tool 1 counts the number of impacts detected by the impact detection unit 12, and when the counted impact number reaches the impact number (shut-off impact number) corresponding to the target torque value, the impact rotary tool 1 Execute the shut-off function to stop the rotation automatically.

  In the embodiment, the shutoff impact number storage unit 17 stores a shutoff impact number corresponding to each set value of the target torque. The shut-off impact number storage section 17 stores, for example, the shut-off impact number corresponding to each of the set values of 30 steps. This means that the user can select one of the 30-step tightening torque values according to the work target. The shut-off impact number storage unit 17 may be configured as a master table, and the storage content may not be updated.

  Note that the shut-off impact number storage unit 17 only needs to store information or data for the setting unit 15 to derive the shut-off impact number corresponding to the target torque value. For example, the shut-off impact number is calculated from the target torque value. A calculation formula to be obtained by calculation may be stored. Conventionally, it has been known that the tightening torque by an impact rotary tool is proportional to the square root of the number of impacts. For this reason, the manufacturer of the impact rotary tool 1 actually measures the number of shut-off impacts for realizing a plurality of tightening torque values using a predetermined screw member and a member to be fastened, and obtains a torque coefficient which is a proportional constant in a calculation formula. The km may be obtained and stored in the shutoff impact number storage unit 17. Even when the shut-off impact number storage unit 17 stores the shut-off impact number corresponding to each set value of the target torque, each target torque value is calculated by adding the torque coefficient km to the square root of each shut-off impact number. Is multiplied by.

FIG. 2 shows the relationship between the target torque value stored in the shut-off impact number storage unit 17 and the shut-off impact number. From the above relationship, when the target torque value is T, the shutoff impact number is N, and the torque coefficient is km, the target torque value T is expressed by the following formula.

  The receiving unit 14 receives an operation input by the user and supplies the operation input to the setting unit 15. The receiving unit 14 has a wireless communication module, and the user performs an operation input on the impact rotary tool 1 using a remote controller attached to the tool. Note that operation buttons and a touch panel may be provided on the tool body, and the reception unit 14 may receive an operation input by the user.

  The setting unit 15 has a function of setting the number of shut-off impacts of the impact mechanism 9. Specifically, the setting unit 15 refers to the contents stored in the shut-off impact number storage unit 17 to set an initial value of the shut-off impact number and to stop the motor rotation at the initially set shut-off impact number. It has a function of correcting the initially set shutoff impact number according to the tightening torque value measured later. In the latter correction function, the setting unit 15 calculates the target torque value when the motor rotation is stopped at the initially set shut-off impact number, and the tightening torque measured by actually stopping the motor rotation at the shut-off impact number. From the relationship with the value, the shutoff impact number is corrected so that the tightening torque value when the rotation of the motor is stopped becomes the target tightening torque value. Hereinafter, the function of the setting unit 15 will be described in detail.

  Before starting the work, the user selects a target torque value using the remote controller. When the accepting unit 14 accepts the selection input of the target torque value, the setting unit 15 refers to the contents stored in the shut-off impact number storage unit 17 to derive the shut-off impact number corresponding to the target torque value. To supply. In the embodiment, the setting unit 15 derives the shut-off impact number and supplies it to the control unit 10, and the control unit 10 sets the shut-off impact number to a state that can be used for the rotation control of the motor 2 by the shut-off impact number. This is called a setting process. The setting unit 15 sets the shutoff impact number derived from the storage content of the shutoff impact number storage unit 17 as an initial value of the shutoff impact number.

  At a work site where the same tightening operation is repeatedly performed, the user sets a target torque value and then checks whether an actual tightening torque value (hereinafter, also referred to as an “actual tightening torque value”) matches the target torque value. . This torque checking operation needs to be performed before starting the tightening operation. The user tightens the same screw member as the work target and the member to be fastened using the impact rotary tool 1 in which the target torque value is set, and reduces the tightening torque of the screw member by a return torque method, a mark method, an additional tightening torque method, or the like. It is measured by a known inspection technique. At this time, if the actual tightening torque value matches the target torque value, the user confirms that the impact rotary tool 1 can be used for the operation without any change.

  However, if the actual tightening torque value does not match the target torque value, the user automatically stops the rotation of the motor 2 at the shut-off impact number stored in the shut-off impact number storage unit 17 and then sets the target tightening torque. Check that the attached torque value cannot be achieved. Therefore, the setting unit 15 of the embodiment has a function of correcting and resetting the number of shutoff impacts so that the screw member can be tightened with the target torque value.

FIG. 3 shows a shut-off impact number corresponding to a predetermined target torque value. Hereinafter, a case where the user sets the target torque value Tm will be described as an example.
When the user sets the target torque value Tm, the setting unit 15 refers to the storage content of the shut-off impact number storage unit 17 and sets the shut-off impact number Nm associated with the target torque value Tm to the shut-off impact number. Set as the initial value. When the user operates the operation switch 16, the control unit 10 supplies a drive instruction according to the operation amount of the operation switch 16 to the motor drive unit 11, and the motor drive unit 11 rotates the motor 2 according to the drive instruction.

  The control unit 10 monitors the output voltage of the impact detection unit 12, and when the output voltage of the impact detection unit 12 exceeds the impact determination voltage Vth, an intermittent rotational impact force is generated on the output shaft 8 by the impact by the impact mechanism 9. Is determined. The control unit 10 may include a comparator that compares the output voltage of the impact detection unit 12 with the impact determination voltage Vth, and may determine that a rotational impact force has occurred on the output shaft 8 from the output of the comparator. The control unit 10 counts the number of impacts detected by the impact detection unit 12. When the counted number of impacts reaches the number of shut-off impacts Nm, the control unit 10 automatically stops the rotation of the motor 2. Thereafter, the user measures the actual tightening torque value of the tightened screw member by a known method.

  FIG. 4 shows a curve C1 representing the relationship between the target torque value and the number of shut-off impacts by a solid line, and an estimated curve C2 representing the relationship between the actual tightening torque value and the number of impacts by a dotted line. In this example, when the control unit 10 automatically stops the rotation of the motor 2 at the shut-off impact number Nm in the torque confirmation work, the actual tightening torque value is measured as Tw.

As described above, the tightening torque value is a value obtained by multiplying the square root of the number of impacts by the impact mechanism 9 by a predetermined torque coefficient. Therefore, if the tightening torque value Tw and the number of impacts (number of impacts) Nm at that time are known, a torque coefficient kw that is a proportional constant is obtained, and an estimated curve C2 representing the number of impacts N corresponding to the actual tightening torque value T is obtained. Can be derived. The estimation curve C2 is expressed by Equation 2 below.

ここで実締付トルク値Ｔｗに対する目標トルク値Ｔｍの比（つまり、Ｔｍ／Ｔｗ）をジョイント係数ｊと呼ぶと、式３と式４とから、

したがって式２と式５とから、推定曲線Ｃ２は、以下の式で表現できる。

Referring to FIG. 4, the curve C1 indicates a tightening torque value corresponding to the number of impacts Nm, and the curve C2 indicates a tightening torque value corresponding to the number of impacts Nm is Tw. Therefore, by substituting the respective values into Equations 1 and 2,

Here, when the ratio of the target torque value Tm to the actual tightening torque value Tw (that is, Tm / Tw) is called a joint coefficient j, from Equations 3 and 4,

Therefore, from Equations 2 and 5, the estimated curve C2 can be expressed by the following equation.

このように締付トルク値Ｔｍを得るための衝撃数Ｎｗは、式７により、ジョイント係数ｊの２乗値と衝撃数Ｎｍとから求められる。 FIG. 5 is a diagram for explaining the number of impacts Nw by the impact mechanism 9 for obtaining the tightening torque value Tm. From Equations 3 and 6, the number of impacts Nw is obtained by Equation 7 below.

As described above, the number of impacts Nw for obtaining the tightening torque value Tm is obtained from the square value of the joint coefficient j and the number of impacts Nm by Expression 7.

  When the user measures the actual tightening torque value Tw when the rotation of the motor 2 is automatically stopped at the initially set shut-off impact number Nm, the setting unit 15 uses the joint coefficient j (= Tm / Tw). Thus, the number of impacts Nw for actually obtaining the tightening torque value Tm can be calculated from Expression 7. Then, when the user measures the actual tightening torque value Tw, the user inputs the actual tightening torque value Tw or the joint coefficient j to the impact rotary tool 1 using a remote controller.

  The receiving unit 14 receives the actual tightening torque value Tw or the value of the joint coefficient j (= Tm / Tw) input by the user. The setting unit 15 calculates the square value of the joint coefficient j using Equation 7, and multiplies the initially set shut-off impact number Nm to obtain the target tightening torque value when the motor rotation is stopped. The number of shut-off impacts Nw that becomes the torque value is obtained. The setting unit 15 supplies the determined number of shut-off impacts Nw to the control unit 10. When the user inputs the actual tightening torque value Tw or the value of the joint coefficient j, the torque checking operation is completed. Thereafter, the control unit 10 uses the shut-off impact number Nw corrected by the setting unit 15 to generate the motor 2 To control the rotation of

  When the joint coefficient j for the work object is determined in this way, the same joint coefficient j can be used even when the target torque value is different for the same work object. Therefore, if there is no change in the work target, when the user changes the target torque value, the setting unit 15 automatically sets the number of shut-off impacts for obtaining the target torque value. Even if the same target torque value is set, if there is a change in the combination of the screw member and the member to be fastened, the user performs a torque check operation each time and measures the actual tightening torque. It is necessary to input a value or a joint coefficient to the impact rotary tool 1.

FIG. 6 shows a flowchart of a process for correcting the initial value of the number of shut-off impacts.
In the torque checking operation, when the user selects the target torque value Tm using the remote controller, the accepting unit 14 accepts the selection input of the target torque value Tm, and the setting unit 15 reads the contents stored in the shut-off impact number storage unit 17. With reference to this, the initial value Nm of the number of shut-off impacts is set (S10).

  When the user fits the screw member into the tip tool provided at the tip of the output shaft 8 and operates the operation switch 16, the control unit 10 supplies a drive instruction for the motor 2 to the motor drive unit 11 (S12). Thereby, the motor 2 is rotated, and the tightening of the screw member is started. The impact detection unit 12 detects the impact applied to the output shaft 8 by the impact mechanism 9, and the control unit 10 counts the number of impacts detected by the impact detection unit 12, and the counted impact number is a shut-off impact. When the number reaches Nm, the rotation of the motor 2 is stopped (S14).

  Then, the user measures the actual tightening torque value Tw of the screw member. If the actual tightening torque value Tw matches the target torque value Tm, the user confirms that the shutoff impact number Nm is appropriate. On the other hand, if the actual tightening torque value Tw is different from the target torque value Tm, the user uses the remote controller to input the actual tightening torque value Tw or the joint coefficient j (= Tm / Tw) to the impact rotary tool 1. input. As another input method, the user may operate the buttons and the touch panel of the impact rotary tool 1 to input the actual tightening torque value Tw or the joint coefficient j. Further, the impact rotary tool 1 may be connected to a terminal device such as a computer, and the actual tightening torque value Tw or the joint coefficient j may be input from the terminal device. The receiving unit 14 receives a value input by the user and supplies the value to the setting unit 15.

  The setting unit 15 derives the shut-off impact number Nw for obtaining the tightening torque value Tm from the value input by the user using Expression 7, and corrects the initially set shut-off impact number Nm. The setting unit 15 supplies the derived shut-off impact number Nw to the control unit 10, and thereafter, the control unit 10 controls the rotation of the motor 2 using the shut-off impact number Nw. According to the embodiment, the setting unit 15 corrects the initially set shutoff impact number from the relationship between the target torque value Tm and the actual tightening torque value Tw, so that the tightening torque can be appropriately controlled. It becomes possible.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of each component or each processing process, and that such modifications are also within the scope of the present invention. .

なおｎ＝０であれば、式１’、式２’、式７’は、式１、式２、式７と同じになる。 In the embodiment, in Equations 1 and 2, the tightening torque is derived from the first impact. However, in the impact rotary tool 1, for example, when a moving average is used in processing time-series data, it is necessary to wait for data processing until the minimum number of data required for data processing is completed. In this case, in the master table, the target torque values for the first few (n) times from the start of the impact are not set, and the setting unit 15 also generates an estimated curve in which the tightening torque is generated from the (n + 1) th impact. Designed to be. At this time, Expressions 1, 2, and 7 are modified as follows.

If n = 0, Equations 1 ′, 2 ′ and 7 ′ are the same as Equations 1, 2 and 7.

  In the embodiment, the user inputs the actual tightening torque value Tw or the joint coefficient j to the impact rotary tool 1, and the impact rotary tool 1 corrects the initially set shutoff impact number Nm to the shutoff impact number Nw. That was explained. This correction process is performed by the setting unit 15. In a modified example, the function of the setting unit 15 is provided in a terminal device such as a computer, and the terminal device performs the correction process to correct the shut-off impact number Nw. May be supplied to the impact rotary tool 1.

  The impact rotary tool 1 of the embodiment has the motor 2 as an electric motor as a drive source, but may have another type of motor, for example, an air motor. In addition, the impact rotary tool 1 of the embodiment is a mechanical rotary tool, but may be another type of impact rotary tool, for example, an oil pulse tool.

The outline of the embodiment of the present invention is as follows.
An impact rotary tool (1) according to an embodiment of the present invention includes an impact mechanism (9) for generating an intermittent rotational impact force on an output shaft (8) by a motor output, and a setting for setting a number of shut-off impacts of the impact mechanism. (15), an impact detection unit (12) applied to the output shaft by the impact mechanism, and the number of impacts detected by the impact detection unit are counted. A control unit (10) for stopping rotation.
The setting unit (15) is configured to determine a relationship between the target tightening torque value when the motor rotation is stopped at the shut-off impact number and the actual tightening torque value measured by actually stopping the motor rotation at the shut-off impact number. Accordingly, the number of shut-off impacts is corrected so that the tightening torque value when the rotation of the motor is stopped becomes the target tightening torque value.

  The setting unit (15) may set an initial value of the number of shut-off impacts, and correct the initially set number of shut-off impacts from the relationship between the target tightening torque value and the actual tightening torque value. Further, the setting unit (15) calculates the square value of (target tightening torque value / actual tightening torque value) so that the tightening torque value when the motor rotation is stopped is equal to the target tightening torque value. The following shutoff impact number may be obtained. The impact rotary tool 1 further includes a receiving unit (14) for receiving an actual tightening torque value or a value of (target tightening torque value / actual tightening torque value) input by the user, and the setting unit (15) Alternatively, the number of shut-off impacts at which the tightening torque value when the rotation of the motor is stopped becomes the target tightening torque value may be determined based on the input value.

  According to another aspect of the present invention, an impact rotary tool (1) for counting the number of impacts by an impact mechanism (9) and stopping rotation of a motor (2) when the counted number of impacts reaches a shut-off impact number. This is a method of setting the number of impacts. This method sets the initial value of the number of shut-off shocks, and actually sets the target tightening torque value when the motor rotation is stopped at the initially set number of shut-off shocks and the actually set number of shut-off shocks. From the relationship with the actual tightening torque value measured when the motor rotation is stopped, the number of shut-off impacts at which the tightening torque value when the motor rotation is stopped becomes the target tightening torque value is determined.

DESCRIPTION OF SYMBOLS 1 ... Impact rotary tool, 2 ... Motor, 9 ... Impact mechanism, 10 ... Control part, 11 ... Motor drive part, 12 ... Impact detection part, 14 ... Reception part , 15... Setting section, 17... Shut-off impact number storage section.

Claims (5)

An impact mechanism that generates an intermittent rotational impact force on an output shaft by a motor output, a setting unit that sets a number of shut-off impacts of the impact mechanism, and an impact detection that detects an impact applied to the output shaft by the impact mechanism And an impact rotary tool comprising: a control unit that counts the number of impacts detected by the impact detection unit, and stops rotation of the motor when the counted number of impacts becomes a shutoff impact number.
Initial and set with the target tightening torque value when stopping the motor in the shut-off number shock, actually initially set shut off the impact speed between the torque value with actual fastening measured by stopping the motor From the relationship, the setting unit corrects the initially set shut-off impact number so that the tightening torque value when the motor rotation is stopped becomes the target tightening torque value.
An impact rotary tool characterized by the following. Further comprising a shut-off impact number storage unit that stores information or data for deriving a shut-off impact number corresponding to the target tightening torque value,
The setting unit refers to the storage content of the shut-off impact number storage unit, and sets an initial value of the shut-off impact number ,
The impact rotary tool according to claim 1, wherein: The setting unit calculates a square value of (target tightening torque value / actual tightening torque value), and thereby shuts off when the tightening torque value when the motor rotation is stopped becomes the target tightening torque value. Find the number of impacts,
The impact rotary tool according to claim 1 or 2, wherein: An actual tightening torque value input by the user or a (target tightening torque value / actual tightening torque value) receiving unit that receives a value;
Based on the input value, the setting unit obtains a shut-off impact number at which the tightening torque value when the motor rotation is stopped becomes the target tightening torque value.
The impact rotary tool according to any one of claims 1 to 3, wherein: Counting the number of impacts by the impact mechanism, a method of setting the number of impacts in the impact rotary tool to stop the rotation of the motor when the counted number of impacts becomes the number of impacts,
Set the initial value of the number of shut-off impacts,
The difference between the target tightening torque value when the motor rotation is stopped at the initially set shut-off impact number and the actual tightening torque value measured by actually stopping the motor rotation at the initially set shut-off impact number from the relationship, so that the tightening torque value when stopping the motor rotation is the torque value with a target tightening, you correct the shutoff number shock is initialized,
A method of setting the number of shut-off impacts, characterized in that:

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