JPH08192370A - Oil pulse impact tool - Google Patents

Abstract

PURPOSE: To previously prevent the leakage of the operating oil due to temperature rise by providing a switch means for cutting the power supply to a motor when the temperature detected by a temperature detecting means exceeds the predetermined temperature. CONSTITUTION: A thermometal cut-out switch TS, which is inserted in series to a power supplying passage to a motor 20, is turned off so as to stop the motor 20 when the temperature of the motor 20 exceeds the predetermined temperature because of the continuous work or the like. Since this motor 20 and an impact device 3 are thermally connected to each other and heating thereof are related with each other, the motor 20 can be stopped before the leakage of the operating oil is generated in the impact device 3. At this stage, an information unit LED, which is formed of a light emitting diode connected in parallel with the thermometal cut-out switch TS, is lighted so as to inform the abnormality, and informs that the motor 20 is stopped because of the temperature rise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pulse impact tool which takes out impact output by utilizing hydraulic pressure.

[0002]

2. Description of the Related Art Among impact tools used for screw tightening and bolt tightening, there is an impact tool which utilizes hydraulic pressure from the rotational force of a rotary drive source to extract impact output. This type, which is called an oil pulse impact tool, has conventionally used an air motor that operates with compressed air as a rotary drive source.

[0003]

In this case, a compressed air source such as a compressor is additionally required, and the air hose for connection with this compressed air source becomes a hindrance to the work.
For this reason, it has been proposed to use an electric motor as a rotary drive source and further use a battery as a power source, thereby eliminating the need for a separate device and eliminating cords to be connected.

However, in the case of the electric type, the following problems newly arise. That is, in the oil pulse impact tool, if the temperature of the impact device rises excessively, the internal pressure will increase due to the expansion of the enclosed hydraulic oil, and the hydraulic oil will leak out. However, since the air motor itself is cooled by the compressed air supplied, it does not serve as a heat source and the impact device can be cooled by the flow of air. It never happened. However, in the electric type, since the electric motor also becomes a heat source and there is no air flow that functions as a coolant, the temperature of the impact device easily rises, and leakage of hydraulic oil becomes a serious problem. There is.

The present invention has been made in view of the above points, and an object of the present invention is to use an electric motor as a rotational power source, and to prevent oil leakage of operating oil due to temperature rise. Providing impact tools.

[0006]

SUMMARY OF THE INVENTION The present invention provides an oil pulse impact tool equipped with an electric motor as a rotary drive source and a hydraulic impact device that operates with the rotational output of the electric motor. It is characterized in that it is equipped with temperature detecting means for detecting the temperature of the impact device, and switch means for cutting off the power supply to the electric motor when the temperature detected by the temperature detecting means exceeds a predetermined temperature. Another feature is that a thermoswitch is used as the temperature detecting means and the switch means, and that a notifying means that operates when the power supply to the electric motor is cut off by the switch means is provided.

[0007]

According to the present invention, when the temperature of the electric motor or the impact device, which is the heat generating portion, becomes equal to or higher than a predetermined temperature, the temperature detecting means for detecting the temperature activates the switch means to cut off the power supply to the electric motor. The temperature of the impact device does not rise to the temperature at which hydraulic oil leaks.

If a thermo switch that serves both as the temperature detecting means and the switch means is used, the number of parts can be reduced, and a notifying means which operates when the power supply to the electric motor is cut off by the switch means is provided. In the case of a motor vehicle, it is possible to inform the user that the reason for stopping the electric motor is an increase in temperature.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the illustrated embodiments. This oil pulse impact tool uses a storage battery in a storage battery pack 9 detachably mounted on a handle portion 11 of a main body 1 as a power source. , A battery-powered electric type in which an electric motor 20 fed through a switch unit 16 that is turned on when the trigger handle 15 is pulled is used as a rotational power source, and a rotary drive source is provided at a rear end portion of the housing 10. And a drive circuit D that controls the rotation speed of the electric motor 20 by changing the duty ratio according to the output of the speed control module in the switch unit 16 that outputs an output according to the pulling condition of the trigger handle 15. Has been paid.

In the gear case 13 made of aluminum die cast on the tip side of the housing 10, a speed reducer 2 for reducing the rotation of the electric motor 20 and a hydraulic impact device 3 for giving an oil pulse impact to the output shaft 5 are provided. Has been paid. The reduction gear 2 meshes with the sun gear 21 fixed to the output shaft of the electric motor 20, the internal gear 22 fixed to the inner peripheral surface of the motor mounting base 12 fixed to the housing 10, and the sun gear 21 and the internal gear 22. It is composed of a planetary mechanism including a plurality of planetary gears 23 and a carrier 24 supporting the planetary gears 23, and a bearing 28 for supporting the carrier 24 is built therein.

The hydraulic impact device 3 includes a liner 30 which is cylindrical and has a "cocoon" type cross section as shown in FIG. 3, and a jacket 31 which surrounds the outer periphery of the liner 30. , The end plates 32, 33 closing both ends of the liner 30, and the vanes 50, 5 attached to the portion of the output shaft 5 surrounded by the liner 30.
0, and hydraulic oil filled in the internal space of the liner 30. When the liner 30 is rotationally driven by the deceleration output from the speed reducer 2, an oil pulse impact is given to the output shaft 5.

For transmission of power from the reduction gear 2 to the impact device 3, the end plate 33 of the liner 30 of the impact device 3 also functions as the carrier 24 supporting the planetary gear 23 of the planetary gear mechanism 2 and the electric motor 20.
The rotation of the planetary gear 23, which is driven by the sun gear 21 which is rotationally driven by, and which rotates and revolves by meshing with the internal gear 22, is transmitted to the liner 30 of the impact device 3. This is achieved by arranging the planetary gear 23 and the carrier 24 of the output part of the planetary gear mechanism, which is the reduction gear 2, in the block on the impact device 3 side instead of in the block composed of the electric motor 20 and the reduction gear 2. When the shafts provided on the end plates 33 that also serve as the carriers 24 are supported by the bearings 28 held by the motor mounting base 12 by connecting the blocks, the planet gears 23 on the impact device 3 side are connected to the electric motor 20. The block on the side of the speed reducer 2 is inserted between the internal gear 22 and the sun gear 21 so as to be meshed therewith, and the connecting portion for rotation transmission of the both blocks is interposed between the both blocks. Instead, the overall length in the axial direction is shortened by positioning it in the speed reducer 2 in one block.

The liner 30 is, as shown in FIG.
The inner surface is provided with sealing surfaces 35, 35 in the major axis direction, respectively, and the sealing surfaces 36, 36 are provided at positions deviated in the minor axis direction and one of the major axis directions, respectively, and the output shaft located in the liner 30. 5 is provided with the pair of vanes 50, 50 biased in a direction of projecting outward by a spring 51, and also has a pair of sealing surfaces 5 on its outer peripheral surface.
It is equipped with 6,56. Where both vanes 50,50
Are arranged on a line passing through the center of the output shaft 5, while the two sealing surfaces 56, 56 are located in a direction orthogonal to the line connecting the vanes 50, 50 and on one vane 50 side. And the vanes 50, 50 are in contact with the seal faces 35, 35 and the seal faces 56, 56 are in contact with the seal faces 35, 35 only during the one rotation of the liner 30 with respect to the output shaft 5 in the positional relationship shown in FIG. The inner space of the liner 30 filled with the hydraulic oil is separated into a plurality of chambers by contacting 36, 36. Since the upper left chamber and the lower right chamber in FIG. 3 communicate with each other through the arrangement portion of the vanes 50, 50, they are separated into three chambers. Further, it is only at this time that the liner 30 is separated in this way. For example, from the state shown in FIG.
In the state of being rotated by 80 °, the sealing surface 36 and the sealing surface 56 are at positions displaced from each other.

Now, when the liner 30 is rotated by the deceleration output of the electric motor 20, if the output shaft 5 is under load, only the liner 30 will rotate, but the output provided with the vane 50 and the sealing surface 56. Shaft 5 and sealing surface 3
Each time the liner 30 provided with 5, 36 reaches the positional relationship shown in FIG. 3, the rotation of the liner 30 is transmitted to the rotary shaft 5 via the hydraulic oil, and a force is applied to the output shaft 5.

By the way, when the positional relationship shown in FIG. 3 is established, one of the two chambers located on both sides of the vane 50 has a smaller volume due to the rotation of the liner 30, and the other has a larger volume. The hydraulic oil in the room of is the high pressure HP, and the hydraulic oil in the latter room is the low pressure LP. Since the pressure value of the hydraulic oil that has become high pressure HP corresponds to the tightening torque when bolting or screwing the output shaft 5, torque control is performed by detecting the pressure value of the hydraulic oil. You will be able to.

It is arranged in the liner 30 and
A pair of ports 37, 38 formed on both sides of one of the two sealing surfaces 36, 36 of the liner 30.
The adjusting shaft 40 in FIG. 3 having an annular groove 41 on the outer peripheral surface for communicating between the two is provided for the torque control together with a relief valve (not shown) for detecting the pressure of hydraulic oil. However, the description of the torque control mechanism is omitted here.

In this oil pulse impact tool, a thermoswitch T is provided on the outer surface of the electric motor 20.
S is provided. As shown in FIG. 4, the thermoswitch switch TS inserted in series in the power feeding path to the electric motor 20.
Turns off and stops the electric motor 20 when the temperature of the electric motor 20 rises above a predetermined temperature due to continuous work or the like. Since the electric motor 20 and the impact device 3 are thermally connected and the respective heat generations are correlated with each other, the electric motor 20 can be stopped before the hydraulic oil leak occurs in the impact device 3. Also, at this time, the thermoswitch T
Notification unit L consisting of a light emitting diode connected in parallel with S
The ED is turned on to inform the user of this abnormality and the fact that the reason for stopping the electric motor 20 is an increase in temperature. The reason why the two light emitting diodes are arranged in the notification unit LED is to cope with the forward and reverse rotation of the electric motor 20.

Here, the thermoswitch TS is connected to the electric motor 2
Although it is arranged on the outer surface of 0 to detect the temperature of the electric motor 20, it may be arranged on the outer surface of the impact device 3 to directly detect the temperature of the impact device 3, Further, the temperature may be indirectly detected at a portion thermally connected to the electric motor 20 or the impact device 3. Further, a temperature sensor, a relay, or a switching element may be used instead of the thermoswitch TS that also serves as the temperature detecting means and the switching means. The notification unit LED may be used or other notification means such as a buzzer may be used.

[0019]

As described above, according to the present invention, when the temperature of the electric motor or the impact device, which is the heat generating portion, becomes a predetermined temperature or higher, the temperature detecting means which detects the temperature activates the switch means to supply electric power to the electric motor. In order to shut off the oil, it is possible to prevent the temperature of the impact device from rising to a temperature at which hydraulic oil leakage occurs.
Problems due to hydraulic oil leakage can be eliminated. Further, unlike the case where a cooling fan is separately provided, increase in power consumption, which is a problem particularly in the case of upsizing and battery power, does not occur.

When a thermo switch that serves both as the temperature detecting means and the switch means is used,
By reducing the number of parts, it is possible to improve the assemblability and reduce the cost, and in the case of providing the notification means that operates when the power supply to the electric motor is cut off by the switch means, the reason why the electric motor stops is that the temperature rises. Since the user can be notified, the user will not be confused.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment.

FIG. 2 is a longitudinal sectional view of the impact device of the above.

FIG. 3 is a transverse sectional view of the impact device of the above.

FIG. 4 is a schematic circuit diagram showing the temperature countermeasure unit of the above.

[Explanation of symbols]

 2 Reducer 3 Impact device 10 Housing 20 Electric motor TS Thermo switch

Claims (4)

[Claims] 1. An oil pulse impact tool comprising an electric motor as a rotary drive source and a hydraulic impact device that operates with its rotational output, the temperature detecting a temperature of an electric motor or an impact device as a heat generating part. An oil pulse impact tool comprising: a detection means and a switch means for cutting off power supply to the electric motor when the temperature detected by the temperature detection means exceeds a predetermined temperature. 2. The oil pulse impact tool according to claim 1, wherein the temperature detecting means and the switch means are formed by a thermo switch. 3. The oil pulse impact tool according to claim 1, further comprising an informing unit which is activated when the power supply to the electric motor is cut off by the switch unit. 4. The oil pulse impact tool according to claim 3, wherein the notifying means is connected in parallel with the switch means inserted in series in the power feeding path to the electric motor.