WO2019026501A1

WO2019026501A1 - Electrically powered tool

Info

Publication number: WO2019026501A1
Application number: PCT/JP2018/024852
Authority: WO
Inventors: 勇樹 ▲高▼橋; 秀幸橋本
Original assignee: 工機ホールディングス株式会社
Priority date: 2017-07-31
Filing date: 2018-06-29
Publication date: 2019-02-07

Abstract

Provided is an electrically powered tool configured so that a space for accommodating a control board is secured within a housing without causing the housing to become large-sized. This hammer drill has: a brushless motor; a power transmission mechanism for transmitting power outputted from the brushless motor, to a front end tool; a first housing (31) for accommodating the brushless motor; a second housing (32) connected to one end of the first housing (31) and accommodating the power transmission mechanism; a tapping screw (90) positioned parallel to the direction of a rotation axis and straddling the first housing (31) and the second housing (32) to affix the first and second housings (31, 32) to each other; and a controller (11) accommodated within the first housing (31) and including a control board for controlling the brushless motor. The position of the tapping screw (90) in a direction perpendicular to the direction of the rotation axis is located inside the first housing (31).

Description

Electric tool

The present invention relates to a power tool such as a hammer drill or a vibration drill.

A power tool such as a hammer drill or a vibration drill applies a striking force or a rotational force to a tool (tip tool) attached to the tip. Such an electric power tool has an electric motor as a power source, a tip tool driven by the electric motor, and a power transmission mechanism for transmitting the power output from the electric motor to the tip tool, and the electric motor The power transmission mechanism is housed in the housing.

The housing that accommodates the electric motor and the power transmission mechanism includes, for example, a first housing in which the electric motor is accommodated, and a second housing in which the power transmission mechanism is accommodated. The first housing and the second housing have a generally cylindrical shape as a whole, and their ends are connected to each other. For example, a first flange portion projecting radially outward is formed at the front end of the first housing in which the electric motor is accommodated, and the same diameter is also formed at the rear end of the second housing in which the power transmission mechanism is accommodated. A second flange portion projecting outward in the direction is formed. In this case, the first flange portion and the second flange portion which are abutted against each other are fixed to each other by screws or other fixing members passing therethrough, and the first housing and the second housing are connected.

JP, 2011-20230, A

A brush motor or a brushless motor is used for the electric motor which is a power source of an electric tool. When a brushless motor is used as a power source, a control board for controlling the brushless motor is essential, and it is necessary to secure a housing space for the control board in the housing. In general, it is preferable to arrange a control board for controlling a brushless motor in the vicinity of the brushless motor. By arranging the control board in the vicinity of the brushless motor, advantages such as shortening of the electric wiring connecting the control board and the brushless motor can be obtained. Therefore, in the above-described embodiment in which the electric motor is accommodated in the first housing and the power transmission mechanism is accommodated in the second housing, both the brushless motor and the control board are preferably accommodated in the first housing. That is, it is preferable to secure a space for housing the control board in the first housing.

However, when the inner diameter of the first housing is enlarged to secure a space for housing the control board, the outer diameter of the first housing including the first flange portion is expanded. Further, the increase in the outer diameter of the first housing including the first flange means that the outer diameter of the second housing including the second flange that is butted to the first flange is also increased.

On the other hand, the housing of the power tool can be grasped by the operator from various directions. Therefore, it is preferable that the outer diameter of the housing of the power tool be of such a size that the operator can hold it firmly with one hand.

That is, when using a brushless motor as a power source of the electric tool, it is required to secure a space for housing the control board in the housing while avoiding the enlargement of the housing (in particular, the increase in diameter). .

An object of the present invention is to secure a space for housing a control board in a housing while avoiding an increase in size of the housing.

The electric power tool according to the present invention comprises a brushless motor, a power transmission mechanism for transmitting power output from the brushless motor to a tip tool parallel to the rotational axis direction of the brushless motor, and the brushless motor being housed first A housing, a second housing connected to one end of the first housing, in which the power transmission mechanism is accommodated, a second housing parallel to the rotation axis direction, and the first housing and the second housing A fixing member for fixing the first housing and the second housing in a straddling manner, and a control substrate accommodated in the first housing for controlling the brushless motor, the fixing member having the rotational axis direction The position in the orthogonal direction is provided so as to be inside the first housing.

According to the present invention, it is possible to secure a space for housing the control board in the housing while avoiding an increase in size of the housing.

It is sectional drawing which shows the structure of a hammer drill. It is a perspective view of a housing. It is an exploded perspective view of a housing. It is another disassembled perspective view of a housing. It is a disassembled sectional view of a housing. It is a sectional view of a housing. It is a disassembled sectional view which shows the modification of a housing. It is sectional drawing which shows the modification of a housing.

Embodiment 1 Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. The power tool according to the present embodiment is a hammer drill 1A shown in FIG. The hammer drill 1A has a function of rotating the tip tool 20 by a driving force output from the brushless motor 10 which is a power source, and a function of striking the tip tool 20. A drill bit is an example of the tip tool 20. The drill bit is used when making holes in concrete or stone. However, the tip tool 20 is replaced as appropriate depending on the type of work on the target or the target.

The hammer drill 1A has a housing 30 shown in FIG. As shown in FIGS. 2 to 4, the housing 30 includes a first housing 31 and a second housing 32 connected to one end of the first housing 31. Furthermore, the first housing 31 is composed of an integrated motor housing 33 and a handle housing 34. In addition, the handle housing 34 is composed of two

housing halves

34 a and 34 b facing each other (a rear portion) of the motor housing 33. In other words, a portion (rear) of the motor housing 33 is covered by a portion (upper) of the handle housing 34. Also, the other part (lower part) of the handle housing 34 forms a grip 2 (FIG. 2) to be gripped by the operator. The handle housing 34 has a screw boss 341 extending in a direction perpendicular to the split surface of the handle housing 34. The screw boss 341 is formed by abutting the screw boss half 341a provided in the housing half 34a and the screw boss half 341b provided in the housing half 34b in the longitudinal direction (left and right direction) of the screw boss 341. A screw (not shown) can be screwed into the screw boss 341. The housing half 34a and the housing half 34b are fixed to each other by screwing the screw through the screw boss half 341b and screwing with the screw boss half 341a. Ru.

As shown in FIG. 1, the first housing 31 houses the controller 11 including the brushless motor 10 and a control substrate for controlling the brushless motor 10, the switching substrate 12, the Hall element substrate 13 and the cooling fan 14. It is done. On the other hand, a power transmission mechanism 40 for transmitting the power mainly output from the brushless motor 10 to the tip tool 20 is accommodated in the second housing 32. Specifically, the brushless motor 10, the switching board 12 and the Hall element board 13 are accommodated in a motor housing 33 (FIGS. 3 and 4). On the other hand, the controller 11 including the control board is accommodated in the accommodation space 3 provided in the first housing 31. The housing space 3 is provided outside the motor housing 33 shown in FIGS. 3 and 4 and inside the handle housing 34. That is, the first housing 31 has the housing space 3 for housing the controller 11 including the control board, and the housing space 3 is located outside the motor housing 33 and inside the handle housing 34. doing. Furthermore, the position of the accommodation space 3 in the rotational axis direction is the opposite side to the second housing 32 with reference to the motor housing 33 (see also FIG. 6). In the following description, the second housing 32 may be referred to as a "gear cover 32". The motor housing 33 has a coupling portion 331. The coupling portion 331 has a through hole 332 extending along the longitudinal direction (left and right direction) of the screw boss 341, and in the state where the handle housing 34 is assembled to the motor housing 33 (FIG. 8), the screw boss 341 penetrates The inside of the hole 332 is inserted. In other words, the motor housing 33 and the handle housing 34 are assembled by fixing the screw boss half 341 a and the screw boss half 341 b to each other so that the screw boss 341 passes through the through hole 332.

As shown in FIG. 1, the brushless motor 10 has a stator 15 and a rotor 17 to which a rotating shaft 16 is fixed. The rotation shaft 16 penetrates the rotor 17 and protrudes from both axial sides of the rotor 17. One end side (rear end side) of the rotary shaft 16 projecting from the rotor 17 is rotatably supported by a bearing 16a, and the other end side (front end side) is rotatably supported by a bearing 16b. Further, the tip end side of the rotating shaft 16 penetrates the cooling fan 14 and the inner cover 35 and enters the gear cover 32, and the driving gear 18 is formed at the tip of the rotating shaft 16.

On the other hand, inside the gear cover 32, an intermediate shaft 41 parallel to the rotation shaft 16 is provided. The intermediate shaft 41 is one of the components of a conversion mechanism that converts power (rotational driving force) output from the brushless motor 10 into reciprocating driving force. The conversion mechanism is one of the components of the power transmission mechanism 40 that transmits the power output from the brushless motor 10 to the tip tool 20. The intermediate shaft 41 is provided with two

gears

41 a and 41 b, and one gear 41 a meshes with the drive gear 18. In the following description, the direction of the rotation axis 16 may be referred to as “rotation axis direction”. The rotation axis direction extends along the aforementioned split surface of the handle housing 34 and is orthogonal to the longitudinal direction of the screw boss 341.

Inside the gear cover 32, a cylinder 50 is provided in parallel with the intermediate shaft 41. Inside the cylinder 50, a piston 51, a striker 52 and an intermediate 53 are disposed in line in this order from the rear to the front, and an air chamber 54 is provided between the piston 51 and the striker 52. It is formed.

Inside the gear cover 32 and around (below) the cylinder 50, a conversion mechanism is accommodated. The conversion mechanism converts the rotational motion of the rotary shaft 16 into the reciprocating motion of the piston 51. The conversion mechanism has the intermediate shaft 41 described above, an inner ring attached to the intermediate shaft 41, an outer ring having a connecting rod, and rolling elements interposed between the inner ring and the outer ring, and the inner ring is the intermediate shaft A spline 41 is engaged with a gear 41 b provided at 41. When the intermediate shaft 41 is rotated by the rotational drive force output from the brushless motor 10 and input to the intermediate shaft 41 via the drive gear 18 and the gear (follower gear) 41a, the gear 41b is rotated. When the gear 41b rotates, the inner ring spline-fitted to the gear 41b rotates. Then, the outer ring moves on the inner ring, and the connecting rod provided on the outer ring swings. The piston 51 reciprocates back and forth in the cylinder 50 as the connecting rod swings. Furthermore, the intermediate shaft 41 is provided with a third gear that is constantly engaged with another gear provided on the outer periphery of the cylinder 50, and the cylinder 50 rotates with the rotation of the intermediate shaft 41. The tool 20 rotates. The impact force and the rotational force are given to the tip tool 20 by these. The tip tool 20 to which the striking force and the rotational force are given in this manner extends in parallel with the rotational axis direction.

The ON / OFF of the brushless motor 10 is switched by the operation of the trigger switch 4 by the operator. Further, the hammer drill 1A of the present embodiment is provided with a forward / reverse switch that switches the rotational direction of the brushless motor 10. When the forward / reverse switch is operated, the direction of the current supplied to the brushless motor 10 changes, the rotational direction of the brushless motor 10 is reversed, and the tip tool 20 is reversely rotated.

A plurality of switching elements (transistors) are mounted on the switching substrate 12 shown in FIG. 1, and a Hall element is mounted on the Hall element substrate 13. Further, a drive circuit is mounted on a control board included in the controller 11. The drive circuit sequentially turns on / off the plurality of switching elements based on the signal output from the Hall element to change the direction of the current flowing in the stator coil. In the present embodiment, a magnet is attached to the cooling fan 14 that rotates integrally with the rotation shaft 16 of the brushless motor 10, and the Hall element detects the passage of the magnet and outputs a signal.

The above is the basic structure and the basic operation of the hammer drill 1A according to the present embodiment. Next, details of the housing 30 in which the above-described components are accommodated will be described.

As described above, the housing 30 is roughly divided into the first housing 31 and the second housing (gear cover) 32, and the first housing 31 is roughly divided into the motor housing 33 and the handle housing 34. However, such distinction is only for convenience of explanation, and the respective housings are integrated.

As shown in FIGS. 2 to 4, the motor housing 33 has a cylindrical shape as a whole, and a front opening 33a is provided at one end (tip) in the rotational axis direction (FIG. 3). The gear cover 32 also has a cylindrical shape as a whole, and a rear opening 32a is provided at one end (rear end) in the rotational axis direction (FIG. 4). The motor housing 33 and the gear cover 32 are fixed in a state in which their end portions face each other with the flange portion 36 of the inner cover 35 interposed therebetween.

As shown in FIG. 3, a through hole 61 is formed inside the motor housing 33. Specifically, fitting portions 60 surrounding the front opening 33a are provided on the periphery of the front opening 33a of the motor housing 33, and through holes 61 are formed at the four corners of the fitting 60, respectively. ing. On the other hand, as shown in FIG. 4, a screw hole 71 as a coupling portion is formed inside the gear cover 32. Specifically, an abutment portion 70 is provided inside the rear opening 32 a of the gear cover 32, and screw holes 71 are formed at the four corners of the abutment portion 70, respectively. As shown in FIG. 5, the through hole 61 provided in the motor housing 33 and the screw hole 71 provided in the gear cover 32 extend in parallel to the rotational axis direction (the left and right direction in FIG. Extended to

As shown in FIG. 6, when the inner cover 35 is inserted from the rear opening 32a (FIG. 5) of the gear cover 32 to the inside of the gear cover 32, the front surface 36a of the flange portion 36 of the inner cover 35 abuts on the gear cover 32. I hit the part 70. Then, the communication holes 81 (FIGS. 3 and 4) provided at the four corners of the flange portion 36 of the inner cover 35 communicate with the corresponding screw holes 71, respectively. Further, when the fitting portion 60 of the motor housing 33 is inserted into the rear opening 32a (FIG. 5) of the gear cover 32 from the rear of the inner cover 35, the end face of the fitting portion 60 is the flange portion 36 of the inner cover 35. Hits the back 36b of the. Then, the through holes 61 provided at the four corners of the fitting portion 60 of the motor housing 33 communicate with the corresponding communication holes 81, respectively. That is, when the gear cover 32, the motor housing 33 and the inner cover 35 are combined in a predetermined order, the flange portion 36 of the inner cover 35 is sandwiched between the contact portion 70 of the gear cover 32 and the fitting portion 60 of the motor housing 33. . At the same time, communication is provided in the flange portion 36 of the inner cover 35 with the through hole 61 provided in the fitting portion 60 of the motor housing 33 and the screw hole 71 provided in the contact portion 70 of the gear cover 32. It communicates through the hole 81. In other words, on the inside of the housing 30, the three of the through hole 61, the communication hole 81 and the screw hole 71 are connected in series.

The first housing 31 (motor housing 33) and the second housing (gear cover) 32 combined as described above are parallel to the rotational axis direction and penetrate the inner cover 35 to form the motor housing 33 and the like. It is fixed by a fixing member straddling the gear cover 32. As shown in FIG. 5, the fixing member in the present embodiment is a tapping screw 90. The tapping screw 90 as a fixing member is inserted into the through hole 61 from the rear of the fitting portion 60 of the motor housing 33. As shown in FIG. 6, the tapping screw 90 inserted into the through hole 61 passes through the communication hole 81 to reach the screw hole 71, and is coupled to the inner circumferential surface of the screw hole 71. As described above, the first housing 31 (motor housing 33) and the second housing (gear cover) 32 are fixed to each other by the tapping screws 90 located inside them. In other words, the tapping screw 90 fixing the motor housing 33 and the gear cover 32 is located inside the motor housing 33 in the direction orthogonal to the rotation axis direction. As a result, as shown in FIG. 6, the central axis X of the tapping screw 90 passes through the accommodation space 3 in which the controller 11 including the control board is accommodated.

As described above, in the present embodiment, the tapping screw 90 for fixing the first housing 31 and the second housing 32 to each other is positioned inside the first housing 31 in the direction orthogonal to the rotation axis direction. ing. Therefore, in order to fix the first housing 31 and the second housing 32, there is no need to provide a flange or other projecting portion at these ends. Therefore, even if the inner diameter of the first housing 31 is enlarged to provide the housing space 3 in the first housing 31, the first housing 31 is provided with a flange portion and other projecting portions, as compared to the case where the first housing 31 is provided. The outer diameter of the first housing 31 is kept small. That is, the housing space 3 for housing the control board in the housing 30 is secured while avoiding the upsizing of the housing 30.

Further, in the present embodiment, when the position of the housing space 3 in the rotational axis direction is based on the motor housing 33, it is on the opposite side to the second housing 32. That is, the housing space 3, the motor housing 33 and the gear cover 32 are disposed in this order from the rear to the front. Therefore, since the brushless motor 10 accommodated in the motor housing 33 and the power transmission mechanism 40 accommodated in the gear cover 32 can be brought as close as possible, the power transmission loss is reduced. Furthermore, since the controller 11 including the control board and the brushless motor 10 are disposed offset in the rotational axis direction (front-rear direction), the control board and the brushless motor 10 in the direction (upper and lower, left and right direction) orthogonal to the rotational axis direction It is not necessary to enlarge the first housing 31 to avoid interference.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, as shown in FIGS. 7 and 8, in some embodiments, the through hole 61 is formed on the inside of the second housing 32 and the screw hole 71 is formed on the inside of the first housing 31. In this embodiment, the tapping screw 90 as the fixing member is inserted into the through hole 61 from the front of the second housing 32 and reaches the screw hole 71 provided in the first housing 31, and the inner periphery of the screw hole 71. Bonded to the face. There is also an embodiment in which the switching element and the Hall element are mounted on a common substrate. Although the 1st housing 31 in the above-mentioned embodiment was constituted from two housings (motor housing 33 and handle housing 34), there is also an embodiment in which the 1st housing is a single housing. The fixing member is not limited to the tapping screw 90. For example, it may be a normal screw provided with an external thread coupled to an internal thread formed in advance on the inner peripheral surface of the screw hole 71.

The electric power tool of the present invention also includes an electric power tool (for example, a hammer) which gives only a striking force to the tip tool, and a power tool (for example, an impact driver) which gives only a rotational force to the tip tool.

DESCRIPTION OF SYMBOLS 1A ... Hammer drill, 2 ... Grip, 3 ... Accommodation space, 4 ... Trigger switch, 10 ... Brushless motor, 11 ... Controller, 12 ... Switching board, 13 ... Hall element board, 14 ... Cooling fan, 16 ... Rotation axis, 20 ... Tool tip 30 30 housing 31 first housing 32 second housing (gear cover) 32a rear opening 33 motor housing 33a front opening 34

handle housing

34a, 34b half housing Body 35 inner cover 36 flange portion 40 power transmission mechanism 50 cylinder 60 fitting portion 61 through hole 70 contact portion 71 screw hole 81 communication hole 90 ... tapping screw, X ... central axis

Claims

With a brushless motor,
A power transmission mechanism for transmitting power output from the brushless motor to a tip tool parallel to the rotational axis direction of the brushless motor;
A first housing in which the brushless motor is accommodated;
A second housing connected to one end of the first housing, in which the power transmission mechanism is accommodated;
A fixing member which is parallel to the rotation axis direction and which fixes the first housing and the second housing across the first housing and the second housing;
A control board accommodated in the first housing and controlling the brushless motor;
The fixing member is provided such that a position in a direction orthogonal to the rotation axis direction is inside the first housing.
Electric tool.
A through hole formed inside the first housing and through which the fixing member is inserted;
And a coupling portion formed inside the second housing and to which the fixing member inserted into the through hole is coupled.
The power tool according to claim 1.
A through hole formed inside the second housing and through which the fixing member is inserted;
And a connecting portion formed inside the first housing and to which the fixing member inserted into the through hole is connected.
The power tool according to claim 1.
The first housing has a housing space for housing the control board,
The central axis of the fixing member passes through the accommodation space.
The power tool according to any one of claims 1 to 3.
The first housing has a cylindrical motor housing in which the brushless motor is housed, and a handle housing that forms a grip gripped by an operator.
The handle housing comprises two opposing housing halves sandwiching a portion of the motor housing,
The power tool according to claim 4.
The housing space is provided outside the motor housing and inside the handle housing,
The position of the accommodation space in the rotational axis direction is opposite to the second housing with respect to the motor housing.
The power tool according to claim 5.