JP2002059371A - Oil unit impact tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool an oil unit even while a driving source for driving the oil unit is stopped, in an oil unit impact tool having the oil unit and a cooling device for cooling the oil unit. SOLUTION: This oil unit impact tool is provided with a motor 11 for driving the oil unit 3, and a second driving source for driving the cooling device 4. The second driving source can be operated independently in relation to the motor 11. Therefore, the cooling device 4 can be operated even if the motor 11 is stopped, and the oil unit 3 can be cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil unit impact tool for driving a tool using an impact force (oil pulse) generated in an oil unit, and more particularly to an improvement in a cooling technique for cooling an oil unit. .

[0002]

2. Description of the Related Art Among tools for performing screw tightening and bolt tightening work, there is an oil unit impact tool that uses a device (so-called oil unit) that generates an impact force using hydraulic pressure. When the temperature of the oil unit used for this type of tool rises excessively due to continuous work, etc.,
There is a problem that the enclosed hydraulic oil expands to increase the internal pressure, and the tightening torque becomes unstable or the hydraulic oil leaks. For this reason, an oil unit impact tool provided with a cooling device for cooling the oil unit has been conventionally developed (Japanese Patent Laid-Open No. 59-129675, Japanese Utility Model Laid-Open No. 4-7).
No. 9056). In the oil unit impact tool described in the above publication, a cooling fan is attached to an output shaft of a drive source that drives the oil unit. Then, when the output shaft of the drive source rotates, the rotation rotates the cooling fan, and the oil unit is cooled by the airflow generated thereby.

[0003]

However, in the above-described oil unit impact tool, since the cooling fan is attached to the output shaft of the drive source of the oil unit, the oil is applied only while the drive source is rotating (during work). The unit could not be cooled. Therefore, when the operation is completed, the oil unit is not cooled, and the temperature of the oil unit increases between the end of the operation and the next operation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an oil unit impact tool which can cool an oil unit while a drive source for driving the oil unit is stopped. Realize.

[0005]

Means for Solving the Problems, Functions and Effects An oil unit impact tool according to claim 1 is provided with an oil unit and a cooling device for cooling the oil unit. , Comprising a first drive source for driving the oil unit and a second drive source for driving the cooling device, wherein the second drive source operates independently of the first drive source. It is possible. In the above oil unit impact tool, a second drive source for driving the cooling device is provided separately from the first drive source for driving the oil unit, and the second drive source is independent of the first drive source. Operable. Therefore, even when the first drive source that drives the oil unit is stopped (other than during work), the cooling device is driven by the second drive source to cool the oil unit.

The oil unit impact tool according to claim 1, further comprising: a temperature detecting means for detecting a temperature of the oil unit; and a second detecting means for detecting a temperature of the oil unit when the temperature detected by the temperature detecting means is higher than a predetermined temperature. Preferably, switch means for operating the second drive source is provided (claim 2). In the above oil unit impact tool, when the temperature of the oil unit rises and the temperature detected by the temperature detecting means becomes equal to or higher than a predetermined temperature, the cooling device automatically operates. Therefore, the cooling device can be automatically operated without depending on the switch operation of the operator.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention described in each of the claims described above can be suitably implemented in the following embodiments. (Mode 1) The oil unit impact tool according to claim 2, wherein the switch means stops the second drive source when the temperature detected by the temperature detection means falls below a second predetermined temperature. Characteristic oil unit impact tool. According to such a configuration, when the temperature detected by the temperature detecting unit becomes equal to or lower than the second predetermined temperature, the second drive source automatically stops, so that the cooling device does not continue to operate more than necessary. . In the case where such a configuration is adopted, a predetermined temperature at which the second drive source is started to operate, and
The second predetermined temperature at which the second drive source is stopped is preferably set such that the latter temperature is lower than the former temperature. According to such a configuration, the cooling unit is stopped after sufficiently cooling the oil unit.
Can be prevented from being repeated frequently.

(Embodiment 2) In the oil unit impact tool according to claim 2, the switch means is provided in the second unit.
An oil unit impact tool, wherein the second drive source is stopped after a predetermined time has elapsed since the drive source was activated. According to such a configuration, even if the second drive source (cooling device) is operated, the operation is automatically stopped after a predetermined time has elapsed, so that it is possible to prevent the cooling device from continuing to operate more than necessary. it can.

[0009]

Next, a soft impact driver according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a partial cross-sectional side view of a soft / soft impact driver 1. First, the mechanical structure of the soft impact driver 1 according to the present embodiment will be described. In the soft impact driver 1, a motor 11 as a drive source for driving the oil unit 3 is housed and fixed in a main body housing 12. A gear is formed at the tip of the output shaft 10 (supported by the bearing 9) of the motor 11, and the planetary gear 8 meshes with this gear. The planetary gear 8 is rotatably mounted on a spindle 6 supported by a bearing 5, and the planetary gear 8 meshes with the internal gear 7. These gear trains constitute a reduction mechanism that reduces the rotation of the motor 11 and transmits the rotation to the oil unit 3. The oil unit 3 is connected to a spindle 6 which is an output shaft of the above-described reduction mechanism.
The oil unit 3 is a known device that instantaneously generates a large torque (oil pulse) on the output shaft 2 using the oil pressure of the oil contained therein (for example, an axial flow fan manufactured by YOKOTA CORPORATION). ). This oil unit 3
At the tip of the output shaft 2 is mounted a box that engages with the heads of nuts. Therefore, when the motor 11 rotates in the soft impact driver 1, the rotation is transmitted to the oil unit 3 via the speed reduction mechanism. Since the load on the output shaft 2 is low at the initial stage of starting to tighten the nuts, the oil unit 3 does not generate an oil pulse, and the rotation transmitted from the motor 11 is output through the oil unit 3 as it is. It is transmitted to the shaft 2. When the nuts are tightened and the load on the output shaft 2 increases, an oil pulse is generated from the oil unit 3 and the nuts are tightened by the impact force.

A temperature detecting sensor 17 is provided on the inner wall of the main body housing 12 where the oil unit 3 is accommodated, at a position close to the rear end (the motor 11 side) of the oil unit 3.
(Thermistor TH1) is provided. Further, an air suction port 18 for sucking air into the main body housing 12 is formed in the main body housing 12 on the tip side (the output shaft 2 side) of the oil unit 3 (below the oil unit 3).
Further, a cooling device 4 that exhausts the air sucked from the air suction port 18 to the outside of the main body housing 12 is provided in the main body housing 12 above the oil unit 3. The cooling device 4 includes a housing 24 fixed to the main body housing 12 as shown in FIG.
Is mounted with an oil-impregnated bearing 26. This oil-impregnated bearing 2
An impeller 21 is attached to one end 20b of the rotary shaft 20a supported by the rotor 6, and a plurality of blades 22 are provided on the outer peripheral wall of the impeller 21. Further, a magnet 23 is attached to the inner peripheral wall of the impeller 21. A stator 25 attached to a housing 24 is arranged at a position facing the magnet 23. A coil winding 28 is wound around the stator 25. The labyrinth structure 2 is provided between the housing 24 and the impeller 21.
7 is provided to prevent oil from leaking from the internal space of the housing 24 (the space accommodating the rotating shaft 20a and the oil-containing bearing 26). Therefore,
In the cooling device 4 described above, when a current flows through the coil winding 28, the impeller 21 is rotated by the electromagnetic force. Thereby, air is sucked into the main body housing 12 from the air suction port 18 of the main body housing 12 to cool the oil unit 3, and the air after cooling the oil unit 3 is discharged from the cooling device 4 to the outside of the main body housing 12. Will be done.

A handle 14 is provided on the main housing 12 of the soft impact driver 1. The handle 14 has a trigger switch 16 for turning the motor 11 on and off, and a positive switch for switching the rotation direction of the motor 11. A reverse switch 13 is provided. Further, a battery pack 15 is detachably attached to the lower end of the handle portion 14.
Electric power is supplied to the cooling device 4. That is, when the trigger switch 16 is operated, electric power is supplied from the battery pack 15 to the motor 11 so that the motor 11
Rotates. Further, the power of the battery pack 15 is supplied to the cooling device 4 via a switching circuit described below. As described above, in this embodiment, the motor 11 and the cooling device 4 are connected to the battery pack 15 by independent power supply paths.
It is connected to the.

Next, the power supply to the cooling device 4 is turned ON-O.
A switching circuit that performs FF will be described. This switching circuit is configured as shown in FIG. 3, and mainly includes a comparator A1 and a transistor Q1 operated by an output of the comparator A1. More specifically, the inverting input terminal of the comparator A1 is connected so that the resistance R1 and the partial pressure of the thermistor TH1 (temperature detection sensor 17) are input. On the other hand, the non-inverting input terminal of the comparator A1 is connected so that the divided voltages of the resistors R2 and R3 are input, and the output terminal of the comparator A1 is connected via a resistor R4. The output terminal of the comparator A1 is connected to the base terminal of the transistor Q1. The collector terminal of the transistor Q1 is connected to a power supply via a cooling device 4 (indicated by FAN in FIG. 3), and the emitter terminal of the transistor Q1 is connected to a ground line. The cooling device 4 (FAN)
The input side and the output side are connected by a diode D1, so that electricity generated by the impeller 21 rotated by inertia when the power is cut off flows from the output side to the input side. The output terminal of the comparator A1 is connected to a power supply line via a resistor R5 and to an earth line via a resistor R7.

Next, the operation of the switching circuit configured as described above will be described. At the beginning of the operation by the soft impact driver 1, the temperature of the oil sealed in the oil unit 3 is low, and the temperature detected by the temperature detection sensor 17 (thermistor TH1) is sufficiently low. Therefore, the resistance of the thermistor TH1 is large, and the voltage input to the inverting input terminal of the comparator A1 becomes higher than the voltage input to the non-inverting input terminal of the comparator A1. Therefore, the output terminal of the comparator A1 is L
At the OW level, the transistor Q1 is not turned on.
Therefore, the impeller 21 of the cooling device 4 does not rotate, and the oil unit 3 is not cooled. If the operation by the soft impact driver 1 continues while the oil unit 3 is not cooled, the temperature detected by the temperature detection sensor 17 (thermistor TH1) gradually increases as shown in FIG. Therefore, the resistance value of the thermistor TH1 gradually decreases, and the voltage of the signal input to the inverting input terminal of the comparator A1 gradually decreases. When the temperature of the thermistor TH1 exceeds a predetermined temperature (50 degrees in the present embodiment), the voltage of the signal input to the non-inverting input terminal of the comparator A1 becomes lower than the voltage of the signal input to the inverting input terminal of the comparator A1. Get higher. Therefore, the state of the output terminal of the comparator A1 becomes HIGH level, and the transistor Q1 is turned on.
Is done. Therefore, power is supplied to the cooling device 4, the impeller 21 of the cooling device 4 rotates, and the oil unit 3 is cooled. Therefore, the temperature detected by the thermistor TH1 (the temperature of the oil unit 3) starts to decrease shortly after the cooling device 4 starts operating. Here, when the output terminal of the comparator A1 becomes HIGH level,
Since this output terminal is connected to the non-inverting input terminal of the comparator A1 via the resistor R4, the comparator A1
Is higher than when the output terminal of the comparator A1 is at a LOW level. Therefore, even if the oil unit 3 is cooled and the temperature of the thermistor TH1 becomes equal to or lower than the predetermined temperature [the temperature at which the output of the comparator A1 switches from the LOW level to the HIGH level (50 ° C. in this embodiment)],
Keeps working. When the temperature of the thermistor TH1 becomes lower than a predetermined temperature (40 degrees in this embodiment), the voltage input to the inverting input terminal of the comparator A1 becomes higher than the voltage input to the non-inverting input terminal of the comparator A1. Therefore, the output terminal of the comparator A1 is LOW.
The mode is switched to the level, and the cooling device 4 stops operating.

As is apparent from the above description, the cooling device 4 in the present embodiment has a drive source for driving the impeller 21 to rotate, and the drive source is the motor 11.
Is turned on and off only by the temperature of the thermistor TH1 irrespective of the trigger switch 16 that turns on and off the switch. Therefore, even when the trigger switch 16 is not operated, that is, when the motor 11 is not rotating and the motor 11 is not working, the cooling device 4 operates and the oil unit 3 is cooled. Further, the cooling device 4 has a predetermined temperature (5 in this embodiment).
0 degree) or more, and operates at a predetermined temperature (in this embodiment,
(40 degrees) or less, the operation stops automatically. Therefore, the operation of the cooling device 4 is automatically turned on and off,
The oil unit 3 can be maintained at an appropriate temperature. For this reason, the variation in the tightening torque is reduced, and the work quality can be kept constant.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

For example, in the above-described embodiment, the cooling device 4 starts operating when the temperature detected by the temperature detection sensor 17 becomes 50 degrees or higher, and stops operating when the temperature becomes 40 degrees or lower. The temperature condition for operating the cooling device 4 is not limited to the above-described temperature condition. That is, any setting may be made as long as it is within the temperature range in which the oil unit 3 operates well. In order to change the set temperature, the basic circuit configuration of the switching circuit may be the same as in the above-described embodiment, and the resistance values of the resistors R1, R2, R3, and R4 may be simply adjusted.

Further, in the above-described embodiment, the switching circuit for turning ON / OFF the power supply to the cooling device 4 by the comparator A1, the transistor Q1, and the like is configured. However, the present invention is not limited to such an example. A switching circuit can also be configured using elements such as a microcomputer.

In the above-described embodiment, an axial fan is used as the cooling device 4. However, the present invention is not limited to such an example, and another cooling device, for example, a cooling system using a Peltier element can be used. .

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of a soft impact driver according to the present embodiment.

FIG. 2 is a partially enlarged sectional view showing a part of the cooling device in an enlarged manner.

FIG. 3 is a circuit diagram of a switching circuit that turns on and off power supply to a cooling device.

FIG. 4 is a graph showing the relationship between temperature and time detected by a temperature detection sensor for explaining the operation of the switching circuit.

[Explanation of symbols]

 1. Soft impact driver 3. Oil unit 4. Cooling device 11. Motor 14. Handle part 15. Battery pack 16. Trigger switch 17. Temperature detection sensor (thermistor) 18. Air suction port

Claims (2)

[Claims] 1. An oil unit impact tool having an oil unit and a cooling device for cooling the oil unit, wherein a first drive source for driving the oil unit and a second drive source for driving the cooling device are provided. An oil unit impact tool, wherein the second drive source is operable independently of the first drive source. 2. The oil unit impact tool according to claim 1, further comprising: a temperature detecting means for detecting a temperature of the oil unit; and wherein the temperature detecting means detects the temperature of the oil unit when the temperature becomes equal to or higher than a predetermined temperature. 2. An oil unit impact tool, comprising: switch means for operating the second drive source.