JP3759635B2 - Hammer drill - Google Patents

Description

[0001]
[Industrial application fields]
The present invention is a hammer drill comprising an electric motor and an electronic control device for keeping a predetermined nominal rotational speed of the electric motor constant during operation, and a drilling operation, chipping operation or It relates to a type in which a combined perforation operation can be selected.
[0002]
[Prior art]
Such combination devices are often used both in industry and non-industry due to their versatility. With respect to examples in which the rotation of the motor shaft in the rotary movement of the drilling jig or the striking movement or combined movement of the striking mechanism can be transmitted, and also in relation to the case in which switching between the corresponding operation types is feasible Please refer to German Patent Application No. 39 32 413. Similarly, as a conventional technique, an electronic control device for a hammer drill that keeps the motor rotation speed constant is known. The electrical motor output is defined by the drilling drive and striking mechanism. In particular, when drilling with a large drilling diameter, a powerful load is applied, so that a clearly higher output is required for the drilling drive than for the hitting mechanism during the chipping operation. Thus, the electrical motor output is fully utilized only in the case of percussion drilling and only about 70-80% is utilized in the case of pure chipping operation. In the case of medium-weight and heavy-weight hammer drills, the striking operation is performed in 50 to 70% of the usage example, and therefore, it is used below the maximum output for more than half of the working time. Therefore, if there is an imbalance between the weight of the machine and the output, the result is uncomfortable for the user. In other words, the user is forced to choose between these drawbacks or using separate devices for drilling and chipping. The use of separate devices for drilling and chipping has the disadvantages of increased procurement costs, requiring a large space and increasing the overall weight.
[0003]
[Problems to be solved by the invention]
In the present invention, the hammer drill of the type described at the beginning is improved so that it can be operated at a motor output of 100% both during the drilling operation and during the chipping operation.
[0004]
[Means for Solving the Problems]
In the present invention, the hammer drill has a switching device for an electronic control device, and the switching device changes the nominal rotational speed of the motor during the chipping operation by another operation type by the operation type selection switch. By being operable so that it can be made higher than the above, the above-mentioned problem could be solved.
[0005]
【The invention's effect】
As a result, the number of strikes increases as the motor speed increases, and as a result, a higher maximum output can be obtained even during chipping operation. The selection of the operation format and the increase in the rotational speed are performed simultaneously via the operation format selection switch.
[0006]
Advantageous configurations of the invention are set forth below in claim 2 and will be described in detail in part in connection with the description of the variants of the invention shown in part in the drawings.
[0007]
【Example】
Embodiments of the invention are illustrated in the drawings and will now be described in detail.
[0008]
The drawings schematically show two different embodiments. 1 and FIG. 2 show one switching device 20, 21, respectively. The switching devices 20, 21 cooperate with the electronic control device 7, and the electronic control device 7 is connected via a main switch 12. The motor is controlled by the power supply network and through the conductor 13.
[0009]
The switching device 20 shown in FIG. 1 has an operation type selection switch 1, and the selection switch 1 has a knob 2 on its outer periphery, and the knob 2 is chipped when the operation type selection switch 1 rotates. The key switch 3 is operated at a position corresponding to the operation, and thereby the resistor 4 is inserted in front of the motor control device 7. On the other hand, in the case of drilling operation or hitting operation, the key switch 3 is located at the illustrated position, and the resistor 5 is inserted in front of the electronic control unit 7. In the case of the embodiment, the resistor 4 has a smaller electrical resistance value allowing a higher nominal speed of the motor during the chipping operation, so that the output can be utilized to the maximum even during the chipping operation. In this case, please understand the nominal rotational speed as the maximum rotational speed of the motor in a given operation type. On the other hand, the actual motor speed can be reduced by using a known manual trigger switch.
[0010]
Instead of a mechanical key switch, it is also possible to use a contactless switch such as a lead contactor or hall transmitter, in which case the contactor is not exposed to external influences. .
[0011]
Of course, the trimming resistors 4 and 5 can be supplied in other forms as long as it meets the requirements and can increase the nominal rotational speed of the motor when the switch 3 is turned on.
[0012]
Since the mover 8 of the motor has a magnet ring 9 having a predetermined number of magnetic poles, the mover 8 rotates via the receiver 11 of the electronic control unit 7 that faces the magnet ring 9 when the mover 8 rotates. Thus, it is possible to supply a signal that matches the cycle of the motor speed. The electronic control unit 7 keeps the cycle constant at a predetermined value that matches the nominal motor speed.
[0013]
FIG. 2 shows a second switching device 21, which has a wedge member 6 on the outer periphery of the operation type selection switch 1, and the higher end of the operation device selection switch 1. Is selected for the chipping operation, the slider supporting the electronic control unit 7 is slid parallel to the motor shaft against the force of the spring. In this case, the motor mover 8 has two magnet rings 9 and 10, which are arranged in front of and behind the direction of the motor shaft. During the drilling or striking operation, the induction receptor 11 of the electronic control device 7 is located facing the magnet ring 9 having a predetermined number of magnetic poles. During the chipping operation, the electronic control unit 7 and thus the induction receptor 11 are also slid by the slider, and the induction receptor 11 is positioned to face the magnet ring 10 having a smaller number of magnetic poles. In this way, the cycle of the signal supplied via the inductive receptor 11 of the control device 7 is reduced so that a control operation is performed to increase the nominal speed of the motor in order to keep the cycle constant. Become. As a result, the nominal rotational speed during the chipping operation can be increased to a desired value. It is sufficient to adjust the induction receptor 11 with respect to the magnet rings 9, 10 in order to switch the nominal rotational speed of the motor corresponding to the selected mode of operation. The control device 7 may be fixed to the casing.
[Brief description of the drawings]
FIG. 1 is a schematic view of a first embodiment of a hammer drill of the present invention with a switchable resistor.
FIG. 2 is a schematic view of a second embodiment of the hammer drill of the present invention with a slidable induction receptor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Operation type selection switch 2 Knob 3 Key switch 4, 5 Resistor 6 Wedge member 7 Control device 8 Movable element 9 Magnet ring 11 Receptor 12 Main switch 13 Conductors 20, 21 Switching device

Claims (5)

A hammer drill comprising an electric motor and an electronic control device (7) for keeping a predetermined nominal rotational speed of the electric motor constant during operation, wherein the drilling operation, chipping operation or In the type in which the combined blow drilling operation can be selected,
The hammer drill has a switching device (20, 21) for an electronic control device (7), which is switched by the operation type selection switch (1) of the motor during the chipping operation. A hammer drill, characterized in that it is operable so that the nominal speed can be higher than the nominal speed in another type of operation. Two trimming resistors (4, 5) are arranged in the electronic control device (7), and the trimming resistors (4, 5) are connected to the operation type selection switch (1) by an electric switch (3 ) Can be selectively switched as a preliminary resistance that affects the motor rotational speed, and the nominal rotational speed of the motor can be increased by adjusting the operation type selection switch (1) to the chipping operation. The hammer drill according to claim 1. Hammer drill according to claim 2, characterized in that the electrical switch (3) is a key switch operable by a protrusion (2) provided on the operation type selection switch (1). Hammer drill according to claim 2, characterized in that the electrical switch (3) is a contactless switch, such as a reed contactor or a Hall transmitter. The electronic control device (7) has an inductive receptor (11), and a first magnet strip (a predetermined number of magnetic poles) located in the mover (8) of the motor via the receptor (11) ( 9) allows a signal of a cycle corresponding to the motor speed to be supplied to the control device, and the mover (8) has a second magnet strip (10) with a different number of magnetic poles and is inductive. The movable receptor (11) can be moved by the operation type selection switch (1), and the inductive receptor (11) is moved from the position facing one magnet strip (9, 10) to the other. The motor speed can be increased by adjusting the operation type selection switch (1) to a chipping operation. The described hammer drill.

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