JP3110344U - Electric spanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an output torque stably, wherein an output torque can be arbitrarily set by the user and the torque output can be controlled to turn off energization to a motor when the output torque reaches a set value. An electric spanner that can be used is provided.
An electric spanner having a motor, a main frame provided with a clutch device, and an electronic brake device, the electronic brake device comprising: torque target value setting means; output torque measuring means; A torque control means for turning off the power supply to the motor when the output torque reaches the target value, and the motor has a starting current and a stopping current different from each other, and torque output control is possible Electric spanner.
[Selection] Figure 1

Description

  The present invention relates to an electric spanner capable of controlling torque output, and more particularly to an electric spanner that turns off power to a motor when output torque reaches a set value.

  When tightening or loosening bolts using conventional spanners (generally referred to as manual or electric spanners, impact wrench, torque wrench, etc., and "spanner"), for example, automobile maintenance factories used air pressure. A large spanner is often used. On the other hand, it is common to place an electric spanner on a car, especially in countries where the distance between states is very long and there are many people who drive long distances, especially in the United States. .

  A typical structure of a conventional small electric spanner used mainly for fastening a tire bolt is shown in a sectional view in FIG. A motor 11 is provided inside the hollow base 1, and a transmission gear 111 is fitted to the tip of the motor 11. A passive gear 121 that meshes with the transmission gear 111 is fitted to one end of the main frame 12. When the motor 11 rotates, the passive gear 121 is driven, and torque is transmitted to the output shaft 13 at the other end of the main frame 12 while reducing the rotational speed. A fitting end 131 is formed at the tip of the output shaft 13, and the fitting end 131 is fitted with a bolt or nut (not shown) and rotated. This tightens or loosens the bolt / nut combination.

  A clutch device 14 is provided in the main frame 12 to convert the continuous output of the motor 11 into intermittent output. In general, the power source is controlled by the switch 15 and the motor 11 can be rotated forward and backward.

  However, in the above-described conventional electric spanner, the output torque cannot be set when the bolts or nuts are loosened or tightened, so the operator determines the output torque based on experience or hearing. In such a method that depends on the operator's sense, the error is extremely large, and the bolt tightening torque tends to be inappropriate.

  In response to such a problem, various types of devices that perform torque control have been proposed, for example, for a large impact wrench using an air motor, for example, Prior Document 1 (Patent Document 1: Japanese Patent Laid-Open No. 6-15579). On the other hand, for a small impact wrench that can be carried, for example, the prior art document 2 (Patent Document 2: Japanese Patent Application Laid-Open No. 7-116968) includes a means for detecting the impact engagement time between the anvil and the hammer, thereby providing an output torque. An invention relating to an impact wrench capable of calculating and controlling the above is described.

  However, further improvement in the efficiency of bolt fastening work using an electric spanner has been demanded, and the development of a technique that is easy for the operator to use and operates stably has been demanded.

JP-A-6-15579 Japanese Patent Laid-Open No. 7-116968

  Therefore, the present invention is an electric spanner in which the output torque can be arbitrarily set by the operator, and when the output torque reaches the set value, the torque output can be controlled to turn off the power to the motor. The main object is to provide an electric spanner capable of obtaining torque. Furthermore, it is a secondary object of the present invention to provide an electric spanner that can easily set an output torque and a bolt fastening operation, and an electric screwdriver or electric drill having a similar mechanism.

  Therefore, in order to solve the above-mentioned problems, the present inventor has intensively studied, a means for setting a torque target value, an output torque is measured, feedback control is performed by comparison with the torque target value, and the motor is started (driven). Based on the knowledge that a stable torque output can be obtained by making the starting current different from the stopping current, especially by making the starting current larger than the stopping current to avoid unstable operation due to voltage fluctuations, the present invention has been completed. Arrived.

That is, according to the following device, each of the above problems can be solved.
(1) An electric spanner having a motor, a main frame provided with a clutch device, and an electronic brake device,
The electronic brake device comprises torque target value setting means, output torque measurement means, and torque control means for turning off the power to the motor when the output torque reaches the target value, and ,
An electric spanner capable of controlling torque output, wherein the motor has a starting current larger than a stopping current.

In addition, by electrically connecting the display panel to the electronic brake device that controls the output torque and displaying the torque target value and the output torque outside the housing of the electric tool, the electric spanner and similar electric tools Based on the knowledge that, without increasing the size, the operator can visually check each torque value without moving the line of sight greatly during the work, and contributes to facilitating the bolt fastening work. I came up with the completion of related devices.
(2) The electric spanner according to (1), wherein the torque target value setting means includes a display for displaying the torque target value or the output torque, and an operation button for arbitrarily setting the target value.
(3) An electric screwdriver or electric drill provided with the motor and electronic brake device according to (1) or (2).

  According to the electric spanner according to the present invention, the torque target value is set, and the feedback control of the motor is performed by calculating the difference from the detected output torque. In addition, since the motor's continuous output is converted to intermittent output by the clutch device, and the motor power is turned off by the electronic brake device as soon as the output torque satisfies the predetermined target value, the experience and feeling of the operator is reduced. The target tightening torque can be obtained without reliance. In addition, in order to obtain such torque target value, it is necessary to repeat driving and stopping of the motor quickly and stably. In the present invention, since the motor starting current and the rotation stopping current are different, the malfunction of the motor is prevented. It enables stable drive and stop control.

  In addition, when setting the torque target value, the electric spanner according to the present invention has an external display device and operation buttons, so that the torque target value can be arbitrarily set without any other input / output means, or the output torque during work can be set. The operator can confirm the time history.

  Furthermore, since the motor and the electronic brake device used in the present invention enable the setting of the target torque and the monitoring and control of the output torque, the mounting target is not limited to the electric spanner. For example, an electric screwdriver or an electric drill can be provided as a power tool that is similar to the electric spanner according to the present invention and includes the motor and the electronic brake, which are main components.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments and examples described later. FIG. 1 is a cross-sectional view of an electric spanner according to the present invention. 2 is a base, 3 is an electronic brake device, 21 is a motor, 22 is a main frame, 23 is an output shaft, 24 is a clutch device, 25 is a switch, 26 is a controller interface, 211 is a transmission gear, 221 is a passive gear, 231 Represents a mating end.

  The electric spanner according to the present invention has a hollow base 2 as a housing. A motor 21 is fixed to the pedestal 2, and a transmission gear 211 is fitted to the rotating shaft of the motor 21. When the motor 21 rotates, the passive gear 221 is driven, and torque is transmitted to the output shaft 23 via the main frame 22 and the clutch device 24. A fitting end 231 is provided at the tip of the output shaft 23 to fit a bolt head (not shown).

  In the electronic brake device 3 characteristic of the present invention, the controller interface 26 and the switch 25 are electrically connected. When the electric spanner is energized, the output torque can be set first. Regardless of whether the output torque is set or not, when the switch 25 is pressed from this state, the motor 21 rotates and the power of the main frame 22 is transmitted to the fitting end 231. The main frame 22 is, for example, an impact mechanism, and specifically, it is generally composed of components constituting an impact rotation type impact wrench composed of an anvil, a hammer, a cam and the like. The clutch device 24 is a device for appropriately converting continuous rotation of the motor 21 into intermittent output. When the motor 21 is driven after setting the target value of the output torque as will be described later, the electronic brake device 3 energizes the motor 21 when it is measured that the output torque has reached the target set value. With the ability to turn off.

  The setting method of the output torque in the present invention is not particularly limited as long as it is composed of a display and operation buttons and is simple and easy for the operator to visually recognize the display. A specific example is shown in FIG. 4 is a panel, 41 is a display, and 411 and 412 are up and down buttons. The panel 4 is electrically connected to the electronic brake device 3 and has a function of performing a work for setting a target value of the motor output torque and displaying the value. Furthermore, the operator can know that the fastening work is almost finished by displaying the measured value of the output torque during driving of the motor.

  The panel 4 includes operation buttons including, for example, a liquid crystal display 41 and up and down buttons 411 and 412. However, the number, shape, and arrangement of the operation buttons are not particularly limited. For example, it is preferable to provide a power button, a reset button, a target value storage button, a display switching button, and the like. When the electric spanner is energized and power is supplied to the panel 4, the output torque can be set by the up and down buttons 411 and 412. The set target torque is stored in the electronic brake device 3, and when the output torque reaches the target torque, the energization to the motor 21 is turned off.

  The function of the electronic brake device 3 will be specifically described with reference to the system block diagram of FIG. The electronic brake device 3 includes a microcontroller 30, an input unit 31, an output unit 32, and a torque measurement unit 33. Further, the motor 21, the main frame 22, the controller interface 26, and the power supply unit 34 are connected.

  When the power supply 34 is turned on, a current flows through the motor 21 and the microcontroller 30. The input unit 31 sets a target value for output torque, and the output unit 32 displays the target value on a liquid crystal display 41, for example. The torque measurement unit 33 monitors the output state of the main frame 22 and inputs a feedback signal based on the amount of deviation from the target value to the microcontroller 30. Conventionally, a plurality of high-accuracy methods have been proposed for measuring the output torque. For example, the method described in the aforementioned prior art document 1 or 2 may be used.

  The microcontroller 30 is a central processing unit (CPU) of the electric spanner according to the present invention, calculates a signal measured and input by the torque measurement unit 33, and controls a signal for controlling the output of the motor 21. Send to interface 26. The controller interface 26 is an electronic control circuit that is connected to the microcontroller 30 and drives a high-load member such as the motor 21. The motor 21 is driven by the controller interface 26 and provides power to the main frame 22. The main frame 22 rotates the output shaft 23 while converting the continuous output of the motor into an intermittent output by the clutch device 24.

  Regarding the embodiment of the electric spanner according to the present invention, the function and operation principle of each unit will be described in more detail. FIG. 4 is a control circuit diagram of this embodiment.

  The electric signal input from R3 is amplified by an amplifier, rectified by a rectifier, and then input to the microcontroller 30 via the input unit 31 as a TTL standard potential. The controller interface 26 is a control circuit composed of a MOSFET or the like. The controller interface 26 interfaces with the microcontroller 30 and drives a high load member such as a motor. The input unit 31 is a man / machine interface and determines an input value of torque. The output unit 32 includes a numeric liquid crystal display 41 and a decoder IC, decodes data sent from the microcontroller 30 and displays the decoded data on the liquid crystal display 41, and indicates a set torque value and an actual torque value.

  The microcontroller 30 is a CPU composed of a microchip or the like. Although the control method of the microcontroller 30 is not particularly limited, a method of accurately controlling the operation of the entire electric spanner according to the present invention by storing software based on a dedicated algorithm for controlling the indirect transmission mechanism in a flash memory is preferable. It is. The power supply unit 34 supplies electric power, for example, with a distribution of 12 V DC to the motor 21 and 5 V DC to the microcontroller 30.

  The electronic brake device 3 used in the present invention uses the microcontroller 30 as a CPU and receives a user command (torque target value) from the input unit 31 when electrically connected to the power supply unit 34. Next, when the switch 25 is turned on, the output torque measurement unit 33 transfers the feedback signal of the output torque value to the microcontroller 30 to perform calculation. The output signal transmitted to the output unit 32 drives the motor 21 and the like by the controller interface 26 and displays the output torque on the display 41. Thereby, the operator can know the fastening state of the bolt or nut, and when the output torque reaches the set value, the energization to the motor 21 is cut off.

  The electronic brake device 3 of the present invention is characterized in that the motor start (drive) current and the rotation stop current are different. Specifically, the starting current is preferably 2 times or more of the stopping current, more preferably 4 times or more. As a result, even when the supply current is reduced to about the start current or the stop current due to the voltage fluctuation, the unstable operation of the motor can be avoided and a stable driving force can be obtained. Furthermore, it is desirable to have functions of overvoltage protection and overcurrent protection and to be able to automatically adjust the output torque value according to the input voltage.

  As another embodiment of the present invention, an electric screwdriver and an electric drill including the electronic brake device 3 and the motor 21 described above are given. That is, these are electric tools of a type that rotates the output shaft in the same manner as the electric spanner, and based on similar technology, have an electronic brake and a motor as main components, and can control the output torque. Specifically, in FIG. 1, an electric screwdriver is obtained if the fitting end 231 is a plus or minus screwdriver, and an electric drill is obtained if it is a drill blade. Since these can be realized by exchanging only the fitting end 231 or the output shaft 23 and the fitting end 231, it is also preferable to provide them as exchangeable attachments.

  The electric spanner according to the present invention is capable of torque control, stable rotation drive, and simple output value setting, so that not only the bolt and nut are fastened but also the desired torque as shown in the second embodiment. It is possible to apply to various power tools that require shaft rotation operation.

Sectional drawing of the electric spanner concerning embodiment of this invention The conceptual diagram of the panel concerning embodiment of this invention System block diagram of an electronic brake device according to an embodiment of the present invention Control circuit diagram according to an embodiment of the present invention Sectional view showing the prior art

Explanation of symbols

1, 2 Base 11, 21 Motor 111, 211 Transmission gear 12, 22 Main frame 121, 221 Passive gear 13, 23 Output shaft 131, 231 Fitting end 14, 24 Clutch device 15, 25 Switch 26 Controller interface 3 Electronic brake Device 30 Microcontroller 31 Input unit 32 Output unit 33 Torque measurement unit 34 Power supply unit 4 Panel 41 Display 411 Up button 412 Down button

Claims (3)

An electric spanner having a motor, a main frame provided with a clutch device, and an electronic brake device,
The electronic brake device includes a torque target value setting means, an output torque measuring means, and a torque control means for turning off the power to the motor when the output torque reaches the target value, and
An electric spanner capable of controlling torque output, wherein the motor has a starting current larger than a stopping current.   The electric spanner according to claim 1, wherein the torque target value setting means includes a display for displaying the torque target value or the output torque, and an operation button for arbitrarily setting the target value. An electric screwdriver or electric drill provided with the motor and electronic brake device according to claim 1 or 2.

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