JP4879608B2 - Electric tool - Google Patents

Description

  The present invention relates to an electric tool, such as an electric drill or an electric screwdriver, which has a commutator motor and is used by switching the rotation direction of an output shaft of the commutator motor between normal rotation and reverse rotation.

  Conventionally, an electric tool having a commutator motor is widely known. The commutator motor includes an armature and a commutator that rotate integrally with the output shaft, and a carbon brush that is in sliding contact with the commutator. In general, the commutator motor is configured such that the output shaft is more easily rotated in the forward rotation direction than in the reverse rotation direction by adjusting the winding direction of the armature coil. For this reason, electric sparks are more likely to be generated between the commutator and the carbon brush at the time of reverse rotation than at the time of normal rotation, and there is a problem that the carbon brush is consumed by the electric spark and the durability of the carbon brush is shortened.

  As countermeasures, electric tools described in Patent Documents 1 and 2 have been developed in the past. The electric tool described in Patent Document 1 is an electric switch that turns on and off the commutator motor, a trigger for operating the electric switch, and a second operation that is operated when the rotation direction of the output shaft of the motor is switched. Member. The second operating member is provided with a pin, and the trigger is formed with a forward rotation groove where the pin is engaged during forward rotation and a reverse rotation groove where the pin is engaged during reverse rotation. . The reverse rotation groove is shorter than the normal rotation groove, and is configured to restrict the amount of pushing of the trigger during reverse rotation to be smaller than that during normal rotation. Therefore, the durability of the carbon brush can be improved by regulating the voltage to the commutator motor during reverse rotation and suppressing the electric spark generated between the carbon brush and the commutator.

The electric tool described in Patent Document 2 has a trigger and a switching lever, and has a movable stopper disposed on the back side of the trigger in the pushing direction in order to regulate the pushing amount of the trigger. The movable stopper is urged upward by a spring. By tilting the switching lever to switch the output shaft from normal rotation to reverse rotation, the movable stopper is pushed downward by the switching lever and moved downward, and at the lower position. The trigger push-in amount is restricted. Therefore, the electric power tool is configured to improve the durability of the carbon brush as in Patent Document 1.
Registered Utility Model No. 2596294 JP 2002-154073 A

  However, since the electric power tool described in Patent Document 1 is configured to restrict the amount of pushing of the trigger by the groove for reverse rotation of the trigger and the pin of the switching lever, the pushing force of the trigger is received by the switching lever. For this reason, the switching lever receives a force, and the force is transmitted to the forward / reverse selector switch operated by the switching lever, which may adversely affect the forward / reverse selector switch. For example, chattering may occur in the forward / reverse selector switch.

The electric power tool described in Patent Document 2 has a complicated configuration that requires a spring or the like that biases the movable stopper upward. In addition, since the movable stopper is provided on the trigger pushing direction side, there is a problem that the portion gripped by the operator is thick in the trigger pushing direction and is difficult to grip.
Therefore, an object of the present invention is to provide an electric tool that does not affect electric parts and can regulate the amount of pushing a trigger during reverse rotation with a simple configuration.

In order to solve the above-described problems, the present invention is an electric tool having a configuration as described in each claim.
According to the first aspect of the present invention, the operation mechanism for operating the rotation direction changer is provided, and the operation mechanism is separated from the first operation member and the first operation member supported movably on the housing. The second operating member is movably supported on the housing side. The second operating member is moved by moving the first operating member, and the rotation direction switch is operated by the second operating member. And, in order to reverse the output shaft of the commutator motor, when the trigger is pushed in with the first operating member moved to the reverse rotation selection position, a regulating portion that abuts against the trigger and regulates the pushing amount of the trigger Is provided on the first operating member. A gap is formed between the first operation member and the second operation member to suppress the force received from the trigger by the restricting portion from the first operation member to the second operation member.

Therefore, the pushing amount of the trigger at the time of reverse rotation is regulated by the regulation unit. Therefore, by regulating the voltage to the commutator motor at the time of reverse rotation, the electric spark generated between the carbon brush and the commutator can be suppressed and the durability of the carbon brush can be improved.
The pushing amount of the trigger is regulated by a regulating portion provided on the first operation member, and the force for pushing the trigger is received by the housing that supports the first operation member. Therefore, the force for pushing the trigger is not transmitted to the rotation direction switch operated by the second operation member supported separately from the first operation member. Therefore, adverse effects on the rotation direction switch are suppressed, and electrical troubles in the rotation direction switch can be suppressed.
The second operation member is moved by the movement of the first operation member and does not require a spring or the like. Therefore, the pushing amount of the trigger at the time of reverse rotation can be regulated with a simple configuration.

  According to the second aspect of the present invention, the trigger has a tilt attachment portion attached to the housing so as to be tiltable at the lower end portion, and the protrusion portion protruding toward the first operation member provided above the trigger has an upper end portion. Have. And, in order to reverse the output shaft of the commutator motor, when the trigger is pushed in with the first operation member moved to the reverse rotation selection position, the protruding portion comes into contact with the restriction portion of the first operation member. It has become.

Therefore, when the trigger is pushed to the housing side during the reverse rotation, the trigger tilts around the lower end portion, and the protruding portion provided at the upper end portion contacts the restricting portion. Therefore, the force pushing the trigger is received at the upper and lower portions of the trigger, and the bending of this trigger can be suppressed as compared with a trigger or the like supported in a cantilever shape. For this reason, it can suppress that a trigger bends and a rotational speed regulator will be operated.
Further, the restricting portion for restricting the pushing amount of the trigger is formed in the first operation member provided above the trigger. Therefore, the restricting portion is not arranged on the trigger pushing direction side as before, and the problem that the portion gripped by the operator becomes thick in the trigger pushing direction does not occur.

According to the third aspect of the present invention, the housing has a grip portion that is gripped by an operator. The grip portion is formed with a through-hole penetrating the grip portion in a direction perpendicular to the pushing direction of the trigger, and the first operation member is movably inserted into the through-hole.
Therefore, the first operating member is supported by the grip portion so as to be movable in a direction perpendicular to the pushing direction of the trigger. Therefore, the force for pushing the trigger is received in the perpendicular direction by the grip portion, and is received with good stability.

A hammer drill (electric tool) 1 according to an embodiment will be described with reference to FIGS.
As shown in FIG. 1, the hammer drill 1 has a housing 2 constituting an outer shell and a commutator motor 3 as a drive source.
The housing 2 has a gear housing portion 2a extending in the front-rear direction, a motor housing portion 2b extending downward from the gear housing portion 2a, and a grip portion 2c formed in the rear portion.

As shown in FIG. 1, a tool holder 12 to which a tip tool (drill bit) 13 is detachably attached is provided in the front end portion of the gear housing portion 2a. A commutator motor 3 is provided in the motor housing portion 2b.
Between the commutator motor 3 and the tool holder 12, a power transmission mechanism 11 that transmits the power of the commutator motor 3 to the tool holder 12 and rotates the tool holder 12 is provided. A hammer mechanism 14 is provided between the commutator motor 3 and the tip tool 13 to convert the power of the commutator motor 3 into a linear impact motion and transmit it to the tip tool 13.

As shown in FIG. 1, the commutator motor 3 includes an output shaft 3a, an armature coil 3b, a commutator 3d, a stator 3c, and a plurality of carbon brushes 3e.
The output shaft 3a is attached to the motor housing portion 2b via a bearing so as to be rotatable. The armature coil 3b is an electromagnet made of a winding, is wound so as to be easily rotated in the forward rotation direction, and is attached to the output shaft 3a. The commutator 3d is provided at the lower end of the output shaft 3a, and is electrically connected to the armature coil 3b.

  The stator 3c is an electromagnet having a winding, and is fixed to the inner peripheral surface of the motor housing portion 2b around the armature coil 3b. The carbon brush 3e is attached to a carbon brush holder provided in the motor housing portion 2b so as to be replaceable. Each carbon brush 3e is made of carbon, is urged so as to be in sliding contact with the commutator 3d, and supplies current to the armature coil 3b in sliding contact with the commutator 3d.

The power transmission mechanism 11 has a plurality of gears disposed between the commutator motor 3 and the tool holder 12 as shown in FIG. These gears cooperate to convert the shaft rotation of the output shaft 3 a of the commutator motor 3 into shaft rotation of the tool holder 12 and transmit it.
The hammer mechanism 14 includes a cylinder 14a, a piston 14b, a striker 14c, and a crank mechanism 14e.

  The crank mechanism 14e has a crank shaft having an eccentric pin and the like, and changes the rotation of the output shaft 3a of the commutator motor 3 into a reciprocating linear motion of the piston 14b. The piston 14b reciprocates linearly in the cylinder 14a and linearly moves the striker 14c by an air spring. The striker 14c linearly moves and collides with the impact bolt 14d, and strikes the tip tool 13 through the impact bolt 14d.

As shown in FIGS. 1 and 2, a rotation speed adjuster 4 and a rotation direction switch 6 are provided in the grip portion 2 c of the housing 2.
The rotational speed adjuster 4 includes a power switch 4b and a sliding resistor 4c, which are electrical components, a case 4a in which electrical components are installed and attached to the housing 2, and an operation element 4d.
The operation element 4d is provided in the case 4a so as to be able to appear and retract, and is urged in a direction protruding from the case 4a by a spring.
As shown in FIGS. 5 and 10, the power switch 4 b is turned from OFF to ON by pushing the operating element 4 d into the case 4 a, and electrically connects the power supply 20 and the commutator motor 3.
The sliding resistor 4c is operated by the operation element 4d to adjust the load voltage to the commutator motor 3, and when the pushing amount of the operation element 4d is increased, the load voltage to the commutator motor 3 is increased.

The rotation direction changer 6 has a changeover switch 6b that is an electrical component as shown in FIG. 10, and a case 6a in which the changeover switch 6b is provided as shown in FIG.
The changeover switch 6b switches the rotation direction of the output shaft 3a of the commutator motor 3 by switching the electrical connection direction between the commutator motor 3 and the power source 20, as shown in FIG.
The case 6 a is attached to the upper surface of the case 4 a of the rotation speed adjuster 4 and is fixed to the housing 2. As shown in FIG. 3, a disc portion 6c is rotatably provided on the upper surface of the case 6a, and the changeover switch 6b is operated by rotating the disc portion 6c.

As shown in FIG. 1, a trigger 5 for operating the rotation speed adjuster 4 and an operation mechanism 7 for operating the rotation direction switch 6 are provided on the grip 2c side.
The trigger 5 is arrange | positioned at the inner edge side of the grip part 2c, as shown in FIG. At the lower end portion of the trigger 5, a tilt attachment portion 5a that is attached to the grip portion 2c so as to be tiltable is provided. Therefore, when the trigger 5 is pushed toward the grip portion 2 c, the trigger 5 tilts, and the operator 4 d of the rotation speed adjuster 4 can be pushed by the contact portion 5 c formed at the center portion of the trigger 5. A projecting portion 5 b that projects toward the first operation member 8 of the operation mechanism 7 disposed above the trigger 5 is formed at the upper end portion of the trigger 5.

The operation mechanism 7 has a first operation member 8 and a second operation member 9 as shown in FIGS.
The first operation member 8 is inserted into a through hole 2 c 1 formed above the trigger 5. The through hole 2c1 penetrates the grip portion 2c in a direction (right and left direction as viewed from the operator) perpendicular to the direction in which the trigger 5 is pushed. The first operation member 8 is slidably supported by the hole wall of the through hole 2c1, and at least the left and right ends are supported by the hole wall. The first operation member 8 is longer than the through-hole 2c1, has at least one end protruding from the through-hole 2c1, and is configured to be easily operated by an operator.

A pair of grooves 8 a and a pair of restricting portions 8 b are formed on the lower surface of the first operation member 8. The pair of grooves 8a penetrates across the front end portion and the rear end portion (left end portion and right end portion in FIG. 3) of the first operation member 8. The restricting portion 8b protrudes from the left wall near the rear end of each groove 8a (the lower wall near the right end in FIG. 3) to the right (upward in FIG. 3).
In the pair of grooves 8a, an upper end portion of the protruding portion 5b of the trigger 5 is installed so as to be movable in the front-rear direction. When the first operating member 8 is moved to the right position (the upper position in FIG. 4, the reverse selection position) as shown in FIG. 4 and the trigger 5 is pushed in as shown in FIG. The amount of pressing of the trigger 5 is restricted by the restriction portion 8b by contacting the restriction portion 8b.

As shown in FIG. 3, the second operating member 9 has a swing mounting portion 9a formed at the center portion, a protruding pin 9c formed at the front end portion, and a long hole 9b formed at the rear end portion. ing.
The swing attachment portion 9 a is formed on the lower surface of the second operation member 9 and is swingably attached to the upper surface of the case 6 a of the rotation direction switch 6. Accordingly, the second operating member 9 swings in the left-right direction (the up-down direction in FIG. 3) around the swing mounting portion 9a.

As shown in FIGS. 2 and 3, the protruding pin 9 c protrudes upward and is inserted into a mounting groove 8 c formed on the lower surface of the first operating member 8. The protruding pin 9c is pushed by the groove wall surface of the mounting groove 8c when the first operating member 8 is slid.
As shown in FIG. 3, a pin portion 6d formed at an eccentric position of the disk portion 6c of the rotation direction switch 6 is inserted into the elongated hole 9b. Therefore, by sliding the first operation member 8, the first operation member 8 swings, the disk portion 6c rotates by the first operation member 8, and the changeover switch 6b is operated by the disk portion 6c.

  As shown in FIG. 2, a switching restricting portion 9 d that protrudes downward is provided at the front end portion of the second operation member 9. The switching restricting portion 9d protrudes toward the upper end portion of the trigger 5, and the upper end portion of the trigger 5 includes two grooves 5d extending from the rear end portion to the front side as shown in FIGS. A partition wall 5e for partitioning is formed. The switching restricting portion 9d is inserted into the groove 5d when the trigger 5 is pushed, and is restricted from moving in the left-right direction by the partition wall 5e. Therefore, it is possible to prevent the second operating member 9 from being erroneously swung while the trigger 5 is pushed.

  Although not shown in FIG. 1 etc., the hammer drill 1 has a mode switching mechanism. The mode switching mechanism has a mode switching switch and a drive path cutting device in order to switch between the hammer drill mode and the drill mode. The drive path cutting device cuts the drive path between the commutator motor 3 and the hammer mechanism 14 by setting the mode switch to the drill mode position. Therefore, the hammer drill 1 is switched by the mode switching mechanism between a drill mode in which only rotational force is applied to the tip tool 13 and a hammer drill mode in which rotational force and linear impact are applied to the tip tool 13.

When driving the hammer drill 1, the mode is selected by the mode changeover switch, and the rotation direction of the tip tool 13 is selected by the first operation member 8.
The first operating member 8 is slid to the normal rotation selection position (lower position in FIG. 3) shown in FIG. 3 or the reverse rotation selection position (upper position in FIG. 3) shown in FIG. When the first operation member 8 is slid, the rotation direction switch 6 is operated via the second operation member 9. The rotation direction switch 6 switches the electric connection direction of the commutator motor 3 and the power supply 20 by the switch 6b by being operated.

  When the first operation member 8 is set to the forward rotation selection position and the trigger 5 is pulled and operated, the protruding portion 5b of the trigger 5 is restricted by the restriction portion 8b of the first operation member 8 as shown in FIGS. Not. For this reason, the pushing amount of the trigger 5 into the grip portion 2c increases, and the voltage load on the commutator motor 3 increases. Thereby, the tool holder 12 is rotated forward at high speed by the commutator motor 3.

  When the first operation member 8 is set to the reverse selection position and the trigger 5 is pulled and operated, the protruding portion 5b of the trigger 5 is restricted by the restriction portion 8b of the first operation member 8 as shown in FIGS. The Therefore, the pushing amount of the trigger 5 into the grip portion 2c is restricted to about half of the normal rotation. As a result, the load voltage to the commutator motor 3 is restricted from being larger than that during forward rotation, and the occurrence of electric sparks generated between the commutator 3d and the carbon brush 3e can be suppressed.

The embodiment is formed as described above.
That is, the hammer drill 1 has an operation mechanism 7 for operating the rotation direction switch 6 as shown in FIG. 2, and the operation mechanism 7 includes a first operation member 8 movably supported by the housing 2, and a first operation member 8. It has the 2nd operation member 9 supported so that the movement to the housing 2 side separately from the one operation member 8 was carried out. The second operating member 9 is moved by moving the first operating member 8, and the rotation direction switch 6 is operated by the second operating member 9. Then, in order to reverse the output shaft 3a of the commutator motor 3, when the trigger 5 is pushed in a state where the first operation member 8 is moved to the reverse rotation selection position, the push amount of the trigger 5 is brought into contact with the trigger 5 The first operating member 8 is provided with a regulating portion 8b that regulates the above.

Therefore, the pushing amount of the trigger 5 at the time of reverse rotation is regulated by the regulating part 8b as shown in FIG. Therefore, by regulating the voltage to the commutator motor 3 at the time of reverse rotation, the electric spark generated between the carbon brush 3e and the commutator 3d can be suppressed and the durability of the carbon brush 3e can be improved (see FIG. 1). ).
As shown in FIG. 7, the pushing amount of the trigger 5 is regulated by a regulating portion 8 b provided on the first operation member 8, and the force pushing the trigger 5 is received by the housing 2 that supports the first operation member 8. It is done. Therefore, the force for pushing the trigger 5 is not transmitted to the rotation direction switch 6 operated by the second operation member 9 supported separately from the first operation member 8. Therefore, the rotation direction switch 6 is not adversely affected, and electrical troubles in the rotation direction switch 6 can be suppressed.
The second operation member 9 is moved by the movement of the first operation member 8 and does not require a spring or the like. Therefore, the pushing amount of the trigger 5 at the time of reverse rotation can be regulated with a simple configuration.

  Further, the trigger 5 has a tilt mounting portion 5a attached to the housing 2 so as to be tiltable as shown in FIG. 2, and a protruding portion 5b protruding toward the first operating member 8 provided above the trigger 5. At the upper end. When the trigger 5 is pushed in a state where the first operating member 8 is moved to the reverse rotation selection position in order to reverse the output shaft 3a of the commutator motor 3, the protruding portion 5b has a first portion as shown in FIG. It is configured to abut against the restricting portion 8 b of one operation member 8.

Therefore, as shown in FIG. 5, when the trigger 5 is pushed toward the housing 2 during the reverse rotation, the trigger 5 tilts about the lower end portion, and the protruding portion 5b provided at the upper end portion contacts the restricting portion 8b. Therefore, the force which pushed the trigger 5 is received in the upper part and the lower part of the trigger 5, and this trigger 5 can suppress bending | flexion compared with the trigger etc. which were supported in the shape of a cantilever. For this reason, it can suppress that the trigger 5 bends and the rotational speed regulator 4 will be operated.
Further, the restricting portion 8 b that restricts the pushing amount of the trigger 5 is formed in the first operation member 8 provided above the trigger 5. For this reason, the restricting portion 8b is not arranged on the side in which the trigger 5 is pushed in as in the past, and there is no problem that the portion gripped by the operator becomes thick in the pushing direction of the trigger 5.

In addition, the housing 2 has a grip portion 2c that is gripped by an operator as shown in FIG. The grip portion 2c is formed with a through hole 2c1 that penetrates the grip portion 2c in a direction perpendicular to the pushing direction of the trigger 5, and the first operating member 8 is movably inserted into the through hole 2c1. Yes.
Accordingly, the first operating member 8 is supported by the grip portion 2c so as to be movable in a direction perpendicular to the pushing direction of the trigger 5. Therefore, the force that pushes the trigger 5 is received in the perpendicular direction by the grip portion 2c, and can be received stably.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and may be the following form.
(1) That is, the above embodiment is a hammer drill. However, a drill without a hammer mechanism or various drivers may be used.
(2) The operation mechanism according to the above embodiment has a first operation member and a second operation member. However, there is one or a plurality of intervening operation members between the first operation member and the second operation member, and the first operation member moves (tilts) the second operation member via these intervening operation members. It may be.
(3) The first operation member according to the above embodiment is provided on the housing so as to be movable left and right. However, the first operating member may be provided in the housing so as to be swingable in the left-right direction.
(4) The second operation member according to the above embodiment is configured to swing left and right with respect to the housing. However, the second operating member may be configured to slide left and right.
(5) The 2nd operation member concerning the above-mentioned embodiment was attached to the case of the rotation direction changer attached to the housing. However, the second operation member may be directly fixed to the housing.
(6) Although the above embodiment uses an AC power supply as a power supply, a DC power supply may be used as a power supply.

It is a left view of a hammer drill. It is a left side enlarged view near the grip part of a hammer drill. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 when normal rotation is selected. FIG. 4 is a diagram corresponding to FIG. 3 when reverse rotation is selected. FIG. 3 is a view corresponding to FIG. 2 when a trigger is pushed. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5 when normal rotation is selected. FIG. 6 is a diagram corresponding to FIG. 5 when reverse rotation is selected. FIG. 5 is a cross-sectional view taken along line VIII-VIII in FIG. 2. FIG. 6 is a cross-sectional view taken along the line IX-IX in FIG. 5. It is an electric circuit diagram between a commutator motor and a power supply.

Explanation of symbols

1 ... hammer drill (electric tool)
2 ... Housing 2c ... Grip part 2c1 ... Through hole 3e ... Carbon brush 3a ... Output shaft 3d ... Commutator 3 ... Commutator motor 3b ... Armature coil 4 ... Rotational speed adjuster 4c ... Sliding resistor 4d ... Operator 4b ... Power switch 5 ... Trigger 5a ... Tilt mounting part 5b ... Protrusion 6b ... Switch Switch 6 ... Rotation direction switch 7 ... Operation mechanism 8 ... First operation member 8b ... Restriction part 9 ... Second operation member 11 ... Power transmission mechanism 12 ... Tool holder 13 ... Tip tool 14 ... Hammer mechanism

Claims (3)

A commutator motor that is a drive source for the tip tool, a rotation speed adjuster that adjusts the rotation speed of the output shaft of the commutator motor by adjusting the load voltage to the commutator motor, and the rotation speed adjuster is operated A rotation direction switch that switches a rotation direction of the output shaft by switching an electrical connection direction between the commutator motor and a power source, and an operation mechanism for operating the rotation direction switch. An electric tool that increases the load voltage to the commutator motor by increasing the amount of pushing the trigger to the housing side,
The operation mechanism includes a first operation member supported movably on a housing, and a second operation member supported movably on the housing side separately from the first operation member. The second operation member is moved by moving the second operation member, and the rotation direction switch is operated by the second operation member.
In order to reverse the output shaft of the commutator motor, when the trigger is pushed in with the first operating member moved to the reverse selection position, the trigger push-in amount is regulated by contacting the trigger. A regulating portion is provided on the first operating member ,
A gap is formed between the first operating member and the second operating member that suppresses the force received from the trigger by the restricting portion from the first operating member to the second operating member. A featured electric tool. The electric tool according to claim 1,
The trigger has a tilting attachment portion attached to the housing so as to be tiltable at the lower end portion, and has a protruding portion protruding toward the first operation member provided above the trigger at the upper end portion,
In order to reverse the output shaft of the commutator motor, when the trigger is pushed in with the first operating member moved to the reverse selection position, the protruding portion contacts the restricting portion of the first operating member. An electric tool characterized by being configured to contact. The electric tool according to claim 1 or 2,
The housing has a grip portion that is gripped by an operator,
The grip part is formed with a through-hole penetrating the grip part in a direction perpendicular to the pushing direction of the trigger, and the first operating member is movably inserted into the through-hole. Electric tool.

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