JPH08336803A - Ventilating structure for power tool - Google Patents

Abstract

PURPOSE: To provide a ventilating structure for a power tool which cools a motor efficiently and has excellent fan performance, and can reduce noise. CONSTITUTION: A ventilating structure in a power tool is equipped with a cooling fan 4 to be rotated by a motor 3 and a ventilating passage for generating air flow which flows to the outside through the motor 3 and the fan 4. The ventilating passage has a ventilating member 6a which is arranged at the downstream side of the fan 4 and forms a part of the ventilating passage. The ventilating member 6a has blowoff windows 8 arranged in a series in the rotating direction of the fan 4 and a plurality of partition walls 9 which partition these windows reciprocally. As for the height of the partition wall, the more the partition wall looks out on the rotating direction of the fan 4, the higher the partition wall becomes toward the side of the fan 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilation structure for cooling air generated by a fan for cooling a motor in an electric tool such as a portable or tabletop electric circular saw, grinder or driver.

[0002]

2. Description of the Related Art Generally, as a ventilation structure for cooling air in an electric tool of this type, a fan is attached to a motor disposed in a motor housing, and the cooling air generated by the fan passes around the motor housing. Alternatively, it is configured to flow out from an outlet provided in a gear housing immediately downstream thereof, and conventionally, as such an outlet, a plurality of elliptical blowing windows are provided along the rotation direction of the fan. The one provided is known. However, many noises such as a wind noise of the fan and a noise of the motor cooling wind are generated from these blowout windows, which impairs the usability of the electric tool. Therefore, for the purpose of reducing the above noise, it is known that a large number of partition walls are provided in each of the blowing windows, and the blowing windows have a slit shape having a certain length in the ventilation direction. In this slit-shaped blowing window structure, the partition walls have the same height (the same distance in the direction of the rotation axis of the fan or the same distance in the radial direction about the rotation axis).

[0003]

In the ventilation structure provided with such slit-shaped blow-out windows, the cooling air flows across the front of the blow-out windows, so that the inside of the blow-out windows on the front side in the rotation direction of the fan has a negative pressure. As a result, the air is sucked into the housing from the outside in reverse, the cooling air is not smoothly discharged, the amount of discharged air is reduced, and the cooling efficiency of the motor is reduced. Further, in this way, the inside of the blowout window on the front side in the rotation direction of the fan becomes a negative pressure and the air is sucked into the housing from the outside, so that the flow of the sucked air is changed to the flow of the air coming from the front of the blowout window. It was supposed that the collision would generate a turbulent flow and generate a collision noise. Furthermore, because the cooling air flows across the front of the blow-out window, wind noise is generated at the partition wall, and the amount of air discharged from the blow-out window to the outside is larger toward the rear side of the fan. In the blowing window on the rear side, the blowing sound is generated by the air flow passing through the blowing window.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a ventilation structure for an electric power tool capable of improving the cooling efficiency of the motor and the fan performance by making the exhaust air volume of the motor cooling air sufficient. Also,
Another object of the present invention is to provide a ventilation structure for an electric tool, in which cooling air is dispersed little by little in a blowing window for efficient discharge, and collision noise, wind noise, and blowing noise between air flows can be reduced. is there.

[0005]

Therefore, the invention according to claim 1 is provided with a cooling fan which is rotationally driven by a motor, and an air passage for generating a flow of air to the outside through the motor and the fan. A ventilation structure in an electric tool comprising: the ventilation passage includes a ventilation member that is disposed on a downstream side of the fan and forms a part of the ventilation passage.
The ventilation member includes a plurality of blow-out windows arranged in the rotation direction of the fan, and a plurality of partition walls for partitioning the blow-out windows from each other, and the height of the partition wall faces the rotation direction of the fan. It is characterized in that the higher it is, the higher it is toward the fan side. In the invention according to claim 1, the height of the partition wall for partitioning the blowing window is higher toward the fan side as it goes in the rotation direction of the fan.
Refrigerant cooling air flowing from the fan is gradually dispersed by the partition wall into the blowing window and smoothly flows out. Therefore, a sufficient amount of exhaust air can be obtained, and the cooling efficiency of the motor and the fan performance are improved. Further, according to such a configuration, negative pressure is suppressed from being generated in the blow-out window located on the front side in the rotation direction of the fan due to the circulation of the return flow above the blow-out window (on the fan side), and the backflow of the blow-out air is prevented. This prevents the collision of air with each other, and the smooth flow reduces wind noise and blowout noise, thus reducing noise as a whole. The invention according to claim 2 is the electric circular saw according to claim 1, wherein the electric tool is provided with a blade case accommodating a saw blade, and the ventilation path extends from the ventilation member to the outside through the inside of the blade case. It is characterized by According to such a configuration, since the cooling air is blown from the passage member into the blade case, the blown air is not blown to the operator, and the wind noise when being blown into the blade case is Marunoco improves the quietness of Marunoco and thus improves its usability.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to FIGS. This example relates to an embodiment in which the present invention is applied to an electric circular saw, and an electric circular saw 1 is shown in FIG. Reference numeral 2 in the drawing denotes a motor housing, in which a drive motor 3 is incorporated. However, in the figure, only the armature of the drive motor 3 is shown. Further, in the figure, 1a indicates a circular saw tooth.

A cooling fan 4 for cooling the motor is attached to the output shaft 3a of the drive motor 3. Therefore, when the drive motor 3 is started, the cooling fan 4 is also rotated integrally, so that the outside air is introduced from the suction port (not shown) provided at the rear end surface (right end surface in the drawing) of the motor housing 2, This flows to the left in the drawing while cooling the drive motor 3, and is sprayed into the gear housing 6 provided on the back surface (right side in the drawing) of the blade case 5.

As shown in the drawing, the gear housing 6 has a cylindrical shape having substantially the same diameter as the motor housing 2, and a passage member 6a facing the cooling fan 4 is formed on the inner peripheral side thereof. The inside of the blade case 5 and the inside of the motor housing 2 are almost partitioned by the passage member 6a. A bearing 7 for rotatably supporting the output shaft 3a of the drive motor 3 is attached at substantially the center of the passage member 6a. An intermediate gear 11a is meshed with the output shaft 3a, the intermediate gear 11a is attached to the main shaft 11, and a circular saw tooth 1a is attached to the tip of the main shaft 11. Therefore, the rotational force of the drive motor 3 is transmitted to the main shaft 11 via the output shaft 3a and the intermediate gear 11, and thereby the circular saw teeth 1a rotate. The main shaft 11 is rotatably supported by bearings 10a and 10b. In this way, the gear housing 6 has a built-in transmission mechanism for transmitting the rotational force of the drive motor 3 to the circular saw teeth 1a.

Further, as shown in FIG. 2, this passage member 6a is provided.
Blow-out windows 8 to 8 for blowing out the outside air sucked by the fan 4 into the blade case 5 are provided in a substantially half-circumference near the outer circumference of the same on the same circumference. In the following description, the rotation direction of the fan 4 (see FIG.
In the counterclockwise direction), the blow-out windows 8 to 8 are distinguished from each other by attaching symbols a to h from the front side. In this example,
Although the case where eight blowing windows 8a to 8h are provided is illustrated, the number is not limited to this, and the number of blowing windows 8 may be changed as necessary.

The blowing windows 8a to 8h are formed by being partitioned by partition walls 9a to 9g, respectively. Here, the passage member 6a of the gear housing 6 has a stepped shape, the central D surface portion is the shallowest (highest, the most front side in FIG. 2), and the outer peripheral C surface portion is the deepest, that is, the lowest. ing. Blow-out windows 8a to 8h are formed in a range of a half circumference in the rotation direction of the cooling fan 4 along the outer circumference from the lowest C surface portion.

Moreover, as shown in FIG. 3, the height of each of the partition walls 9a to 9g gradually changes. That is,
The frontmost partition wall 9a in the rotation direction of the cooling fan 4
Although it is one step higher than the C-plane portion, it is the lowest, and the partition walls 9b → 9c are turned toward the rotation direction of the cooling fan 4 below.
→ 9d → 9e → 9f becomes higher in a stepwise manner, and the partition wall 9g closest to the tip in the rotational direction is formed to be the highest. However, the last partition wall 9g is one step lower than the D surface portion. As a result, the ventilation path extending from the C surface portion to the D surface portion in the counterclockwise direction is provided so as to be gradually shallow.

Eight blowing windows 8a to 8h are formed by the partition walls 9a to 9g whose heights are gradually changed in this way, and the blowing windows 8a to 8h are opened in the blade case 5, respectively. ing. Therefore, the cooling air blown to the passage member 6a of the gear housing 6 by the cooling fan 4 flows in the counterclockwise direction on the inner peripheral side of the gear housing 6 while passing through the blowing windows 8a to 8g to the front, that is, the blade. It is blown into the case 5.

Incidentally, a part of the D portion, which is a side portion of the path from the C surface portion to the blowing windows 8a to 8c (a portion denoted by reference numeral 6b in FIG. 2) is located outside the center of the passage member 6a. It is formed so as to be inclined in a downward direction, so that the cooling air can flow into the blow-out windows 8a to 8c more smoothly.

According to the ventilation structure thus constructed,
Since the partition walls 9a to 9g for partitioning the blow-out windows 8a to 8h are gradually increased along the rotation direction of the cooling fan 4, that is, the circulation direction of the cooling air, the cooling air is gradually fed to the blow-out windows 8a to 8h. The particles are dispersed and efficiently blown into the blade case 5, whereby the blowing noise is further reduced, and the cooling efficiency of the motor 3 and the performance of the cooling fan 4 are improved.

Assuming that the partition walls are formed at the same height, for example, the cooling air flows across the front of the blow-out window as described in the section of the prior art.
The inside of the blow-out window on the front side in the direction of rotation of the fan becomes negative pressure, and the air is sucked into the housing from the outside in the opposite direction. It will decrease. More specifically, if each partition wall is formed at the same height, the cooling air recirculation is less likely to hit the partition wall, so the amount of air blown out through the blow-out window is reduced, and therefore it is not blown out. As a result, the amount of air that recirculates increases, and as a result, negative pressure is generated locally (particularly near the inlets of the blow-out windows 8g and 8h on the tip side), and conversely the outside air is sucked in from inside the blade case through the blow-out window ( It is also possible that the wind will flow backwards.

Further, according to the ventilation structure of this embodiment, the cooling air is not blown from the side portion of the motor housing 2 but is blown into the blade case 5, so that a wind noise (cooling air blowing noise) is generated. Is confined in the blade case 5, noise is greatly reduced compared to a configuration in which it is directly blown to the outside, the quietness of the electric circular saw 1 is greatly improved, and the usability thereof is improved. Further, since the cooling air is blown into the blade case 5, the cooling air is not blown to the operator, and in this respect also, the feeling of use of the electric circular saw 1 is improved.

As described above, according to the ventilation structure of this embodiment, the partition walls 9a to 9g are gradually increased along the circulation direction of the cooling air, so that the cooling air is dispersed in a well-balanced manner. The partition walls 9a to 9g are blown against the partition walls 9a to 9g, so that the cooling air is smoothly blown out into the blade case 5 through the blow-out windows 8a to 8h, whereby the quietness of the electric marunoco 1 is further enhanced.

The first embodiment described above can be implemented with various modifications. For example, the gear housing and the blade case are not limited to an integral structure and may be separate bodies. The housing or the motor housing may be divided into two parts.

Next, a second application of the present invention to a grinder
An embodiment will be described below with reference to FIGS.

A grinder 51, the main part of which is shown in FIG. 4, has a motor housing 52 for accommodating a drive motor 53. A fan 54 for cooling the motor is attached to an output shaft 53a of the drive motor 53. Also, the motor housing 52
An air intake port (not shown) is provided in the rear part. A gear housing 55 is attached to the front portion of the motor housing 52, and the gear housing 55 supports the output shaft 53a of the drive motor 53 via a bearing 56.

A bearing box 57 is attached to the lower part of the gear housing 55, and a spindle 58 is arranged in the bearing box 57 in the vertical direction, that is, in the direction perpendicular to the output shaft 53a of the drive motor 53. Spindle 5
8 is a bearing 55 on the upper end by a gear housing 55.
And the center portion is supported by the bearing box 57 via the bearing 60, and the lower end projects downward from the bearing box 57. A grindstone 61 is attached to the lower end of the spindle 58 by a nut 62 and a flange 63, and a wheel cover 64 that covers the grindstone 61 in a partially exposed state is attached to the lower part of the bearing box 55.

A bevel gear 65 is key-fixed to the tip of the output shaft 53a inside the gear housing 55.
A bevel gear 66 having a larger number of teeth than that of the bevel gear 65 is key-fixed to the spindle 58.

Here, in the gear housing 55, a bearing 56 that supports the output shaft 53a of the drive motor 53.
Is attached to the passage member 67 that faces the fan 54 in the axial direction.
In this passage member 67, as shown in FIG. 5, blowing windows 68a to 68c are provided in the range of approximately 90 ° in the circumferential direction.
The groups are symmetrically arranged in a vertical pair with respect to the output shaft 53a. The blowout windows 68a to 68c are arranged in the rotation direction of the fan 54 (clockwise direction in the drawing) in the order of 68a, 68b, 68c. It is divided by. A wall surface 67a of the passage member 67 is located in front of the blow-out window 68a and behind the blow-out window 68c, and a partition wall 69c is provided in a portion of the wall surface 67a adjacent to the blow-out window 68c. In FIG. 4, the passage member 67 is shown by the EE cross section of FIG.

As shown in FIG. 6, partition walls 69a-69.
Similarly to the partition walls 9a to 9g of the first embodiment, c is a partition wall 69a → 69b toward the rotation direction of the fan 54.
→ It is gradually increasing in the order of 69c.

In this embodiment, the blowing window 68
The sides of a to 68c opposite to the fan 54 and the opposite side communicate with the outside air directly.

In the present embodiment, when the fan 54 is rotated by the activation of the motor 53, air is introduced into the motor housing 52 from the suction port, and after cooling the motor 53, it is exhausted to the outside through the blowing windows 68a to 68c. . Here, the blowing windows 68a to 68c have walls 69a that become higher in the rotation direction of the fan 54, as in the first embodiment.
Since it is equipped with ~ 69c, the cooling air is blown through each blowing window 68.
The particles a to 68c are dispersed little by little and are efficiently blown out to the outside, so that the blowing noise is reduced, and the cooling efficiency of the motor 53 and the performance of the fan 54 are improved. Further, in this embodiment, since the pair of upper and lower blowing windows 68a to 68c are provided in the passage member 67, there is an advantage that the ventilation area is increased and the above effect is further enhanced.

As described above, the example in which the present invention is applied to the circular saw in the first embodiment and the example in which the present invention is applied to the grinder are shown in the second embodiment. Then, the present invention can be applied to any other electric tools such as a driver. Further, although the air is directly discharged to the outside in the second embodiment, the air may be discharged through the wheel cover, so that the same effect as that obtained through the blade case in the first embodiment can be obtained. . Also,
In the above-mentioned embodiments, the blow-through windows are all penetrated in a direction parallel to the axial direction of the fan, but the partition wall may be formed in an inclined shape so that it is slightly inclined in the rotational direction of the fan.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of an electric circular saw according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and is a plan view of a gear housing.

FIG. 3 is a development view taken along line BB of FIG. 2 and is a vertical cross-sectional view of a blowing window.

FIG. 4 is a partially cutaway side view of a main part of the grinder showing the second embodiment of the present invention.

5 is a cross-sectional view taken along the line GG of FIG. 4, which is a plan view of the gear housing.

FIG. 6 is a development view taken along line FF of FIG. 5, which is a vertical cross-sectional view of a blowing window.

[Explanation of Codes] 1 ... Electric Marunoco 2 ... Motor housing 3 ... Drive motor 3a ... Output shaft 4 ... Cooling fan 5 ... Blade case 6 ... Gear housing, 6a ... Passage member 8 (8a-8h) ... Blowout window 9 ( 9a to 9g) ... Partition wall C surface portion ... Deepest surface, D surface portion ... Shallowest surface

Claims (2)

[Claims] 1. A ventilation structure in an electric power tool, comprising: a cooling fan that is rotationally driven by a motor; and a ventilation path that causes a flow of air to the outside through the motor and the fan. The passage has a ventilation member that is arranged on the downstream side of the fan and forms a part of the ventilation passage, and the ventilation member has a plurality of blowing windows arranged in the rotation direction of the fan and these blowing windows. A ventilation structure for an electric power tool, comprising: a plurality of partition walls that are partitioned from each other, and the height of the partition walls increases toward the fan side in the direction of rotation of the fan. 2. The ventilation structure according to claim 1, wherein the power tool is an electric circular saw provided with a blade case accommodating a saw blade, and the ventilation passage extends from the ventilation member to the outside through the inside of the blade case.