JP7360600B2 - blower - Google Patents

Description

The present invention relates to a blower equipped with a brushless motor.

Air dusters, which spray gas to blow away dust, are used in maintenance work on precision equipment. As air dusters, disposable duster cans filled with contents having a low boiling point and electric blowers that suck and compress surrounding air are known (for example, see Patent Document 1). Electric blowers have several advantages over duster cans.

For example, in the case of a duster can, the can is cooled by the heat of vaporization of the injected contents, so even if the contents remain, the internal pressure may drop and the can cannot be used continuously. Electric blowers have no such restrictions and can be used continuously.

For example, in the case of a duster can, it is necessary to carry a spare can in case the contents are used up and to take the used can home. It also takes time to punch holes in the cans you bring home and dispose of them. If the blower is electric, the only spare item you need to carry is a spare battery that is smaller than a duster can. Because the battery can be recharged and used repeatedly, it has a smaller environmental impact than disposable duster cans.

For example, in the case of a duster can, the main content DME (dimethyl ether) is flammable, so it cannot be used in large quantities in places where there is fire or where static electricity is likely to be generated. There are duster cans that do not contain DME and are filled only with nonflammable carbon dioxide gas, but they are expensive and uneconomical. Additionally, since carbon dioxide gas has a large greenhouse effect, it is desirable to reduce the amount emitted from the perspective of environmental impact. In the case of a blower, it is the surrounding air that is injected.

Utility Model Publication No. 6-77873

However, with electric blowers, the amount of air discharged from the nozzle tends to be affected by the remaining amount of the battery. Since dust cannot be blown away unless air is vigorously jetted from the nozzle, it becomes difficult to use as an air duster once the motor can no longer be rotated at a predetermined speed. In the case of an electric blower, even if there is enough battery power left to rotate the motor slowly, the air volume is insufficient, so it is necessary to replace the battery with a spare one.

In order to make the air volume less dependent on the remaining battery power, it is possible to install a brushless motor in the blower instead of a brush motor, and control the motor operation so that the rotation speed does not drop even when the battery power decreases. It will be done. However, a brushless motor requires a switching element that determines the timing of applying battery voltage.

Brushless motors are more difficult to use in high-temperature environments than brush motors because their switching elements are susceptible to heat generation. The blower includes a compressor that compresses air adiabatically. Compressors generate more heat than motors, so it is even more difficult to combine them with switching elements. An object of the present invention is to solve such problems and provide a blower that can be used for a long time with high output.

A blower according to one aspect of the present invention blows out compressed air. The blower includes a compressor, a brushless motor, a battery, a switching element, and a housing. A compressor compresses air. A brushless motor drives the compressor. The battery applies voltage to drive the brushless motor. The switching element determines when to apply battery voltage. The housing has a main body portion in which the compression portion is housed, and a grip portion protruding from the main body portion. The compressor is housed in the main body, while the switching element is arranged in the grip.

According to this aspect, since the switching element that controls the brushless motor is separated from the compressor, it is less susceptible to the effects of heat generation from the compressor. The switching element can determine the timing to shorten the energization time when the battery is near full charge, and to lengthen the energization time when the battery is low, so the brushless motor can be operated without being affected by the remaining battery power. The rotation speed can be kept constant. It is possible to provide a blower that can be used for a long time with high output.

The above aspect may further include a battery attachment part provided at the end of the grip part to which a battery is attached, and a power line connecting the switching element and the brushless motor. The switching element may be provided in the battery attachment part, and the power line may extend along the longitudinal direction of the grip part.

According to this aspect, the switching element can be placed apart from the brushless motor by the length of the power line. Even if blowers become more compact, the grip portion will still have a certain length so that it can be easily held by the operator. Since the length of the power line can be freely designed within the range in the longitudinal direction of the grip, the switching element can be moved away to a position where it is less susceptible to the effects of heat generated by the brushless motor.

In the above aspect, the battery attachment part may include a battery connection board provided with a battery connection terminal electrically connected to the battery. The switching element may be mounted on the battery connection board.

According to this aspect, since the switching element is mounted on the existing battery connection board on which the battery connection terminal was provided, there is no need to prepare a new board exclusively for the switching element and mount it on the blower. In other words, since there is no need to increase the number of substrates to mount switching elements, the number of parts can be reduced and the blower can be made smaller and lighter.

The above embodiment may further include a cooling fan that cools the brushless motor and the switching element.

According to this aspect, the temperature of the switching element can be suppressed from increasing by actively cooling with the cooling fan.

In the above arrangement, the compressor and the switching element may be located on opposite sides of the cooling fan.

According to this aspect, the air flow changes in the cooling fan. Since the cooling fan prevents heat from moving from the compressor to the switching element, the switching element is less susceptible to heat generation from the compressor.

According to the present invention, it is possible to provide a blower that can be used for a long time with high output.

FIG. 1 is a perspective view showing an example of a blower according to an embodiment of the present invention. FIG. 2 is a sectional view showing the internal structure of the blower shown in FIG. FIG. 3 is a perspective view of the compressor shown in FIG. 2. FIG. 4 is a perspective view of the transmission mechanism shown in FIG. 3. FIG. 5 is an exploded perspective view of the crankshaft shown in FIG. 4. FIG. 6 is a perspective view showing an example of the battery connection board shown in FIG. 2. FIG. 7 is a left side view showing a first modification of the embodiment of the present invention. FIG. 8 is a sectional view showing a second modification of the embodiment of the present invention.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, those with the same reference numerals have the same or similar configurations. The hand-held blower 1 has a grip portion 12 protruding from a main body portion 11 (see FIG. 1). The compressor 50 (see FIGS. 3 to 5) housed in the main body 11 adiabatically compresses air, and therefore generates a large amount of heat.

One of the characteristics of the blower 1 of the present invention is that the switching element 34 of the brushless motor 30 is arranged not in the main body part 11 but in the grip part 12 (see FIG. 2). Since the switching element 34 is arranged in the grip part 12 which is not easily affected by the compressor 50, it is possible to provide the blower 1 which can be mounted with the brushless motor 30 and can be used for a long time with high output.

The switching element 34 is preferably mounted on the battery connection board 22 provided at the lower end of the grip portion 12 (see FIG. 6). By mounting the switching element 34 on the existing battery connection board 22, the number of parts can be reduced and the blower 1 can be made smaller and lighter. Note that a new circuit board 29 on which the switching element 34 is mounted may be added to the grip portion 12 (see FIGS. 7 and 8). Each configuration will be described in detail below with reference to FIGS. 1 to 8.

FIG. 1 is a perspective view showing an example of a blower 1 according to an embodiment of the present invention. As shown in FIG. 1, the blower 1 is a handy type that is driven by a battery 20. The housing 10 of the blower 1 is formed in an L-shape or a T-shape, and includes a main body 11 and a grip 12 protruding from the main body 11. When a trigger 13 provided on a grip portion 12 is pulled, the blower 1 injects compressed air from a nozzle 14 attached to the tip of a main body portion 11.

In the illustrated example, the blower 1 is configured to allow a battery 20 to be attached and detached. A battery attachment portion 21 for attaching the battery 20 is provided at a portion (lower end portion) including the protruding end (lower end) 12E of the grip portion 12 and its vicinity. Note that the blower 1 may be configured such that the battery 20 is built into the grip portion 12 without being detachable from the battery attachment portion 21.

FIG. 2 is a sectional view showing the internal structure of the blower 1 shown in FIG. As shown in FIG. 2, the blower 1 further includes a compressor 50, a brushless motor 30, and a transmission mechanism 40 in addition to the housing 10 and battery 20 described above. The battery 20 applies voltage to drive the brushless motor 30. The battery attachment section 21 described above includes a battery connection board 22. The battery connection board 22 is provided with a battery connection terminal 24 that is electrically connected to the battery 20 .

The compressor 50 sucks and compresses surrounding air. In the illustrated example, the compressor 50 is configured as a reciprocating compressor. Note that the compression method of the compressor 50 is not limited to the reciprocating method, and may be other methods. The compressor 50 will be described in detail later with reference to FIGS. 3 and 4.

Brushless motor 30 drives compressor 50 , and transmission mechanism 40 transmits the driving force of brushless motor 30 to compressor 50 . In the illustrated example, the transmission mechanism 40 converts the rotational motion of the brushless motor 30 into reciprocating motion of the piston 52 and transmits the same. The transmission mechanism 40 will be described in detail later with reference to FIGS. 3 to 5.

The brushless motor 30 includes a cylindrical motor core, a motor housing 31 that accommodates the motor core, and a control section electrically connected to the motor core. The motor core includes a stator 32 and a rotor 33. The control unit controls the timing of applying the voltage of the battery 20 and rotates the rotor 33 with respect to the stator 32 .

The control section includes a switching element 34 that determines the timing of applying the voltage of the battery 20. In the blower 1 of the present invention, the compressor 50 is housed in the main body part 11, while the switching element 34 is arranged in the grip part 12. The switching element 31 will be described in detail later with reference to FIGS. 6 to 8. A motor connection terminal 35 is provided on the outer peripheral surface of the motor housing 31. The switching element 34 is electrically connected to the motor connection terminal 35 via the power line 25.

In the illustrated example, the brushless motor 30 is configured as an inner rotor type brushless DC motor in which a rotor 33 rotates inside a stator 32. Note that the brushless motor 30 is not limited to an inner rotor type, but may be an outer rotor type. The rotor 33 includes, for example, a cylindrical rotor core (rotor core) and a plurality of permanent magnets fixed to the outer peripheral surface of the rotor core.

The stator 32 includes, for example, a plurality of bobbins arranged along the rotational direction of the rotor 33. A magnet wire (winding wire) is wound around each bobbin. The stator 32 may further include a stator core (stator core) through which the magnetic flux of the magnet wire passes. The respective magnet wires are interconnected and connected to the motor connection terminal 35. The stator 32 is provided with a rotation angle sensor such as a Hall element that detects the rotation angle of the rotor 33. Note that the rotation angle sensor may be an encoder or the like, or a resolver or the like. The rotation angle sensor may be omitted and the rotation angle may be detected from the waveform of the induced voltage generated by the rotation of the rotor 33.

An output shaft 36 that outputs the driving force of the brushless motor 30 is fixed to the rotation center of the rotor 33 . In the illustrated example, the output shaft 36 extends along the longitudinal direction (vertical direction) of the grip portion 12 and passes through the rotor 33 . A bearing 37 that supports the output shaft 36 is attached to the motor housing 31 . In the illustrated example, the bearings 37 are arranged as a pair of upper and lower bearings with the rotor 33 in between, and the center of the stator 32 and the rotation axis of the rotor 33 are aligned.

FIG. 3 is a perspective view of the compressor 50 shown in FIG. 2. As shown in FIG. 3, the compressor 50 includes a cylindrical cylinder 51. The cylinder 51 extends in a direction intersecting the longitudinal direction of the grip portion 12 described above. Inside the cylinder 51, a piston 52 and the like, which will be described later, are accommodated. A funnel-shaped cylinder head 53 is attached to the tip of the cylinder 51. A discharge valve 55 (shown in FIG. 2) is interposed between the cylinder 51 and the cylinder head 53. The discharge valve 55 closes the flow path between the cylinder 51 and the cylinder head 53 until the pressure inside the cylinder 51 reaches a pressure suitable for blowing off dust or more.

The transmission mechanism 40 includes a crankcase 41 and a crankshaft 42 housed in the crankcase 41. A crank gear 44 forming a part of the crankshaft 42 meshes with a motor gear 38 of the brushless motor 30. In the illustrated example, the cylinder 51 of the compressor 50 is configured as an integral structure with the crankcase 41 of the transmission mechanism 40.

FIG. 4 is a perspective view showing the transmission mechanism 40 shown in FIG. 3. A bearing 47 is attached to the above-mentioned crankcase 41, as shown in FIG. 4. The bearing 47 rotatably supports the crankshaft 42. The transmission mechanism 40 further includes a connecting rod 43 in addition to the crankcase 41 and crankshaft 42 described above.

The connecting rod 43 connects the crank arm 46 of the crankshaft 42 and the piston 52 of the compressor 50. A crank pin 461 fixed to the crank arm 46 swingably supports the connecting rod 43. A suction valve (check valve) 54 is attached to the piston 52 . The suction valve 54 allows air flowing into the cylinder 51 described above to pass therethrough, and blocks air flowing out from the cylinder 51.

FIG. 5 is an exploded perspective view of the crankshaft 42 shown in FIG. 4. As shown in FIG. As shown in FIG. 5, the crankshaft 42 further includes a crank journal 45 extending along the rotation axis of the crank gear 44, in addition to the above-described crank gear 44 and crank arm 46.

In the illustrated example, one end of the crank journal 45 has a D-cut surface (flattened) to prevent rotation, and passes through the center of rotation of the crank gear 44 . The crank arm 46 is fixed to the other end of the crank journal 45. The above-mentioned crank pin 461 is inserted into a pin boss 462 eccentric from the rotation center of the crank arm 46.

The blower 1 of the present invention may include a cooling fan 48 that cools the motor housing 31 and the switching element 34 of the brushless motor 30. In the illustrated example, the cooling fan 48 is integrally molded with the crank gear 44. This will be explained with reference to FIG. 2 again. As shown in FIG. 2, the compressor 50 is located above the cooling fan 48. The switching element 34 is located below the cooling fan 48. The compressor 50 and the switching element 34 are located on opposite sides of the cooling fan 48.

FIG. 6 is a perspective view showing an example of the battery connection board 22 shown in FIG. 2. As shown in FIG. 6, a battery connection terminal 24 that is electrically connected to the battery 20 is attached to the battery connection board 22. In the illustrated example, the battery connection board 22 and the battery connection terminals 24 are housed in a bracket 23 formed in a deep dish shape from an insulating material such as a resin material. Preferably, the bracket 23 is filled with resin. The filled resin covers the battery connection board 22 and the like housed in the bracket 23, so that the waterproof and dustproof properties of the battery connection board 22 can be ensured.

In the illustrated example, the switching element 34 is mounted on the battery connection board 22. By arranging the switching element 34 on the battery connection board 22 and sealing the battery connection board 22 with resin, the waterproof and dustproof properties of the switching element 34 can be easily improved. The control section of the brushless motor 30 described above may further include another control element 39 in addition to the switching element 34. The control element 39 may be mounted on the battery connection board 22 together with the switching element 34. Even if the number of switching elements 34 and the like increases, if they are mounted on the existing battery connection board 22, there is no need to add a new circuit board 29, which will be described later. By reducing the number of parts, the blower 1 can be configured to be small and lightweight.

However, the arrangement of the switching element 34 is not limited to the location on the battery connection board 22. FIG. 7 is a left side view showing a first modification of the embodiment of the present invention. As in the modification shown in FIG. 7, a new circuit board 29 may be added to the battery mounting portion 21, and the switching element 34 may be mounted on the circuit board 29. In the illustrated example, the circuit board 29 is connected to the battery connection board 22. By arranging the battery connection board 22 and the circuit board 29 side by side and sealing the battery connection board 22 with resin, the waterproof and dustproof properties of the circuit board 29 and the switching element 34 mounted on the circuit board 29 can be easily maintained. can be increased.

FIG. 8 is a sectional view showing a second modification of the embodiment of the present invention. As in the modification shown in FIG. 8, a new circuit board 29 may be added to a portion of the protruding end 12E that is different from the battery attachment portion 21, and the switching element 34 may be mounted on the circuit board 29. In the grip portion 12, for example, there is more space near the trigger 13 than in the vicinity of the protruding end 12E. According to the modification shown in FIGS. 7 and 8, the degree of freedom in layout design can be increased.

According to the blower 1 of the embodiment of the present invention and its modification configured as described above, as shown in FIG. 2, the switching element 34 that controls the brushless motor 30 is separated from the compressor 50. Therefore, it is not easily affected by the heat generated by the compressor 50. Even when the remaining capacity of the battery 20 decreases, the timing can be determined so that the switching element 34 keeps the rotation speed of the brushless motor 30 constant, and the blower 1 can be provided with high output and can be used for a long time.

As shown in FIG. 2, the switching element 34 is disposed at the battery mounting portion 21 at the lower end of the grip portion 12, and is connected to the brushless motor 30 via a power line 25 extending over the grip portion 12. Since the switching element 34 can be moved away from the brushless motor 30 by the length of the power line 25, the influence of heat generated by the brushless motor 30 can be suppressed. In particular, as shown in FIG. 6, if the switching element 34 is mounted on the existing battery connection board 22, the number of parts can be reduced and the blower 1 can be made smaller and lighter.

As shown in FIG. 2, the compressor 50 and the switching element 34 are located on opposite sides of the cooling fan 48. As a result, the cooling fan 48 can actively cool the switching element 34, thereby suppressing the temperature rise of the switching element 34. Transfer of heat from compressor 50 toward switching element 34 can be prevented by cooling fan 48 .

The embodiments described above are intended to facilitate understanding of the present invention, and are not intended to be interpreted as limiting the present invention. Each element included in the embodiment, as well as its arrangement, material, conditions, shape, size, etc., are not limited to those illustrated, and can be changed as appropriate. Further, it is possible to partially replace or combine the structures shown in different embodiments.

DESCRIPTION OF SYMBOLS 1...Blower, 10...Housing, 11...Body part, 12...Grip part, 12E...Protruding end, 13...Trigger, 14...Nozzle, 20...Battery, 21...Battery mounting part, 22...Battery connection board, 23...Bracket , 24...Battery connection terminal, 25...Power line, 29...Additional circuit board, 30...Brushless motor, 31...Motor housing, 32...Stator, 33...Rotor, 34...Switching element, 35...Motor connection terminal, 36... Output shaft, 37... Bearing, 38... Motor gear, 39... Control element, 40... Transmission mechanism, 41... Crank case, 42... Crank shaft, 43... Connecting rod, 44... Crank gear, 45... Crank journal, 46... Crank arm , 47... bearing, 48... cooling fan, 50... compressor, 51... cylinder, 52... piston, 53... cylinder head, 54... suction valve, 55... discharge valve, 461... crank pin, 462... pin boss.

Claims (3)

A blower that blows out compressed air,
A compressor that compresses air;
a brushless motor that drives the compressor;
a battery that applies voltage to drive the brushless motor;
a switching element that determines the timing of applying voltage to the battery;
a housing having a main body in which the compressor is housed and a grip protruding from the main body ;
A cooling fan that cools the brushless motor and the switching element ,
The compressor is housed in the main body, while
The switching element is arranged on the grip part so as to be separated from the compressor and the brushless motor arranged connected to the compressor ,
The compressor and the switching element are located on opposite sides of the cooling fan ,
Blower. a battery attachment part provided at an end of the grip part and to which the battery is attached;
further comprising a power line connecting the switching element and the brushless motor,
The switching element is provided in the battery attachment part,
The power line extends along the longitudinal direction of the grip part,
A blower according to claim 1. The battery attachment part includes a battery connection board provided with a battery connection terminal electrically connected to the battery,
the switching element is mounted on the battery connection board;
The blower according to claim 2.

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