JP2022032132A - Working machine - Google Patents

Abstract

To improve cooling efficiency of a fan in a work machine having a rear cover and a main housing split into left and right parts.SOLUTION: A housing 10 of a work machine 1 comprises: a main housing 10 split into left and right parts; and a cup-shaped rear cover 60. Ventilation windows 18 for suctioning air are formed at left and right side surfaces of the main housing 10, and ventilation windows 64 (exhaust ports) for exhausting air exhausted from a fan to the outside are formed at the rear cover 60. A through hole 65 which penetrates to a protruding part 14 side of the main housing 10 in a downward direction is formed at the rear cover 60. Air is flowed into the protruding part 14 of the main housing 10 through the through hole 65, and air is exhausted to the outside through ventilation windows 19 formed at left and right sides of the protruding part 14. Addition of the ventilation windows 19 in this way increases a total area of the exhaust port in the downsized housing.SELECTED DRAWING: Figure 2

Description

INDUSTRIAL APPLICABILITY The present invention improves the cooling performance in a working machine in which a tip tool is operated by using a motor as a drive source.

A work machine that drives a motor using the power supply of a removable battery pack and operates a tip tool to perform work is widely used. An impact tool is an example of such a working machine, and the working machine uses a battery pack as a power source to drive a motor. The motor of the work machine is held by a housing made of synthetic resin that can be divided into a plurality of parts. In the impact tool disclosed in Patent Document 1, a housing made of a synthetic resin is formed by three members, a left-right split type main housing and a substantially cup-shaped rear cover that covers an opening at the rear of the main housing.

Japanese Unexamined Patent Publication No. 2020-082522

In a portable work machine such as Patent Document 1, since there is a strong demand for miniaturization of the work machine, the housing is designed to be as compact as possible, but as a result of promoting the miniaturization of the housing, the cooling performance is improved. There is a problem that the place to increase the wind window is limited. In addition, with the pursuit of miniaturization of the housing and the increase in motor output due to the demand for improved output, ensuring cooling performance has become an increasingly important issue.

The present invention has been made in view of the above background, and an object of the present invention is to provide a working machine having improved cooling performance.
Another object of the present invention is to provide a working machine capable of suppressing the exhaust from being applied to the hand of a worker holding the handle.

The following is a description of typical features of the invention disclosed in the present application.
According to one feature of the invention, a motor that drives a tip tool, a main housing that houses at least a portion of the motor and has a fuselage that extends in the anterior-posterior direction and opens rearward, and is connected to the opening. A rear cover, a protruding portion provided in the main housing extending rearward from the opening, a fan driven by the rotation of a motor, and a first intake portion provided in the fuselage portion to take in external air into the fuselage portion by the fan. In a work machine having a first exhaust portion provided on the rear cover and discharging air taken in from the first intake portion by a fan, the first exhaust portion is a side surface (outer peripheral surface) of the rear cover facing the protruding portion. It is provided in. The first exhaust unit may be provided on the lower side surface of the rear cover. A handle portion gripped by an operator is provided below the main housing, and a protruding portion is provided on the lower portion of the rear cover.

According to another feature of the present invention, the second intake portion is formed at a position facing the first exhaust portion of the protruding portion, and the air discharged from the first exhaust portion is re-entered into the main housing from the second intake portion. The inflowing air is discharged to the outside through the second exhaust portion formed in the main housing. Further, on the left and right side surfaces or the upper side surface of the rear cover, a third exhaust portion for discharging the air taken in from the first intake portion by the fan to the outside is formed at a position not facing the protruding portion. The second exhaust portion is provided on the protruding portion. Further, a switch operation unit for starting the motor and a switching lever for switching the rotation direction of the motor are provided so as to be exposed from the inside of the main housing to the outside, and the air taken in from the second intake unit is provided. A part of it is configured to be discharged to the outside through the gap between the operation unit and the main housing and / or the gap between the switching lever and the main housing.

According to still another feature of the present invention, the second exhaust portion is arranged above the handle portion of the main housing, and the air exhausted from the second exhaust portion is the hand of the operator holding the handle portion. It is discharged in a direction other than. At least a part of the outer surface of the main housing and the rear cover is formed of an elastomer, and the connection portion between the first exhaust portion and the second intake portion is sealed by the gap between the elastomer on the main housing side and the elastomer on the rear cover side. Elastomer.

According to still another feature of the present invention, a gap is provided between the rear cover and the protruding portion so that the air discharged from the first exhaust portion is discharged to the atmosphere through the gap. This gap is formed so as to open in the left-right direction or rearward. The upper surface of the protruding portion may have a concave shape or a bow shape. Further, a battery pack mounting portion to which the battery pack can be attached and detached is provided at the lower end of the handle portion, and the main housing is configured to be split left and right, and is configured to have a body portion, a handle portion, and a battery pack mounting portion.

According to the present invention, in a working machine in which a motor for driving a tip tool, a main housing having a tubular body portion, and a rear cover connected to a rear opening of the main housing and having a structure different from that of the main housing are combined. By providing the first through hole of the rear cover on a surface other than the left and right side surfaces of the rear cover, the area of the exhaust port can be increased as compared with the conventional case, and the flow rate of the cooling air can be increased. Further, a wind window formed on the protruding portion side of the main housing by forming a protruding portion extending behind the rear opening of the main housing below the rear cover and forming an air passage on the protruding portion side from the rear cover. Since the air is discharged to the outside through (4th through hole, discharge part), it is possible to further increase the displacement from only the air windows (2nd through hole) formed on the left and right side surfaces of the rear cover. become. By providing a flat space (gap portion) extending on both the left and right sides and the rear side between the first through hole of the rear cover and the protruding portion of the main housing, the air is exhausted from the gap to the outside. It is possible to prevent the exhaust from hitting the hands of the operator who grips the handle.

It is a vertical sectional view of the impact tool 1 which concerns on embodiment of this invention. It is a partial side view of the impact tool 1 of FIG. It is an enlarged view of the part A of FIG. It is a partially enlarged view which shows the modification 1 to 3 of the Example of this invention. It is a vertical sectional view of the impact tool 1A which concerns on the 2nd Embodiment of this invention. FIG. 5 is a rear view of the body portion 11 of the impact tool 1A of FIG. It is a vertical sectional view of the impact tool 1B which concerns on the 3rd Embodiment of this invention. FIG. 7 is a rear view of the body portion 11 of the impact tool 1B of FIG. 7. It is a figure of the impact tool 1C which concerns on the 1st modification of 3rd Embodiment of this invention, (A) is the vertical sectional view which passes through the rotation axis A1, and (B) is the back view. It is a figure of the impact tool 1D which concerns on the 2nd modification of 3rd Embodiment of this invention, (A) is the vertical sectional view which passes through the rotation axis A1, and (B) is the back view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following figures, an impact tool will be used as an example of the working machine, and the same parts will be described with the same reference numerals. Further, in the present specification, the front-back, left-right, and up-down directions are described as the directions shown in the drawings.

FIG. 1 is a vertical sectional view of an impact tool 1 according to an embodiment of the present invention. The impact tool 1 is for fastening a tip tool such as a bit (not shown), and is an aspect of a working machine. The impact tool 1 uses a rechargeable battery pack 100 as a power source, drives a rotary striking mechanism using a motor 20 as a drive source, and converts the rotation of the rotating member into an intermittent striking force in the rotational direction by the rotary striking mechanism to strike. It drives the anvil 55 connected to the mechanism unit. The housing of the impact tool 1 is composed of a left-right split type main housing 10, a hammer case 3 connected to the front side of the main housing 10, and a rear cover (rear housing) 60 that covers the rear opening of the main housing 10. To.

The main housing 10 is formed below a substantially cylindrical body portion 11 extending in the front-rear direction, a handle portion 12 connected to the body portion 11 so as to form a substantially T shape in a side view, and a lower portion of the handle portion 12. It has a battery pack mounting portion 13. In the main housing 10 of this embodiment, in addition to the front opening 11a (see FIG. 2 for reference numerals) of the cylindrical body portion 11, a rear opening portion 11b (see FIG. 2 for reference numerals) is formed on the rear side as well. The rear opening 11b is closed by the rear cover 60. A metal hammer case 3 is connected to the front opening 11a. The hammer case 3 is fixed so as to be sandwiched from the left-right direction by the split type main housing 10. The outside of the hammer case 3 is covered with a synthetic resin cover 5 so that the operator cannot directly touch the metal portion of the hammer case 5. The rear end side of the cover 5 is connected to the front opening 11a (see FIG. 2 for reference numerals) of the main housing 10.

The handle portion 12 extends downward so as to be substantially orthogonal to the central axis (rotation axis A1) of the body portion 11, and the operator grips the handle portion 12 with one hand as shown by the dotted line of the hand 110. A trigger lever 6a is provided at a position where the index finger of the hand 110 is located when the hand is gripped. The trigger lever 6a is an operation unit of the trigger switch 6 for controlling the on / off and rotation speed of the motor. Normally, it is located forward as shown in FIG. 1 and can be moved backward from the state shown in FIG. 1 by the hand 110. be. Above the trigger lever 6a, a forward / reverse switching lever 7 for switching the rotation direction of the motor is provided.

A battery pack mounting portion 13 is formed on the lower side of the handle portion 12 for mounting the battery pack 100. The battery pack mounting portion 13 is a diameter-expanded portion formed so as to extend in the radial direction (orthogonal direction) from the longitudinal central axis of the handle portion 12. A control circuit board 34 for controlling the rotation of the motor 20 is mounted in the battery pack mounting portion 13 of the main housing 10. Various control elements (not shown) including a microcomputer for controlling the on / off, rotation direction, and rotation speed of the motor 20 are mounted on the control circuit board 34. The battery pack 100 accommodates a plurality of secondary batteries such as lithium-ion batteries, and can be removed from the main housing 10 by moving the battery pack 100 forward while pushing the latch button 101 from the mounted state shown in FIG. Is possible. The power supply of the impact tool 1 of this embodiment is arbitrary, and may be one using not only the battery pack 100 but also a commercial power supply supplied via an AC power cable.

The split type main housing 10 is made of synthetic resin, and a plurality of screw bosses 16a to 16h for screwing are formed on one side (left side), and the main housing 10 on the other side (right side) (not shown) has a plurality of screw bosses 16a to 16h. A screw hole is formed. The left and right main housings 10 are screwed while sandwiching the hammer case 3 on the front side, and then an integrated rear cover 60 is attached to the main housing 10 with a plurality of screws (not visible in the figure). The rear cover 60 has a cup shape, and an opening surface 63 (see FIG. 2 for reference numerals) is formed on the front side, and a rear wall portion 62 which is a bottom surface of the cup is formed on the rear side.

The motor 20 which is a drive source is housed in the space defined by the body portion 11 and the rear cover 60. The rotary shaft 25 of the motor 20 is arranged so as to extend in the front-rear direction, and on the front side of the rotary shaft 25, a reduction mechanism 40 using planetary gears and the rotational force generated by the output of the reduction mechanism 40 are converted into a striking force. The rotary striking mechanism 50 for transmitting to the tip tool holding portion 35 is arranged side by side on the rotary axis A1. The brushless motor 20 is driven by using an inverter circuit (not shown), in which a rotor core 23 having a permanent magnet 24 rotates inside, and a stator in which a coil 22 is wound around a stator core 21 is located on the outer peripheral side. Be placed. A rotary shaft 25 penetrates the rotor core 23, and the rotary shaft is pivotally supported by a bearing 28 on the front side and is pivotally supported by a bearing 29 on the rear side. The bearing 28 is a ball bearing, and its outer ring is held by the inner cover 44. The bearing 29 is a ball bearing and is held by a bearing holder 68 formed on the inner wall side of the rear cover 60.

The hammer case 3 has a bell-shaped shape with a gradually narrowed tip, a cylindrical through hole 3a is formed at the tip, and a bearing 49 such as a needle bearing is mounted inside the through hole 3a. Inside the hammer case 3, a rotary striking mechanism 50 including an anvil 55, a deceleration mechanism 40, and bearings 45 and 49 are housed, and the inside is sufficiently filled with lubricating grease. The opening on the rear side of the hammer case 3 is closed by the inner cover 44. The anvil 55 exposed to the front side from the through hole 3a on the front side of the hammer case 3 constitutes an output shaft, and a tip tool holding portion 35 for holding a tip tool (not shown) is provided at the tip thereof.

The opening surface 63 of the rear cover 60 is connected to the rear opening 11b of the main housing 10. A semiconductor switching element, for example, a substantially circular circuit board 30 on which a hall IC 31 is mounted is provided on the front side of the motor 20. The circuit board 30 is on the front side of the motor 20, that is, on the main housing 10 side, and fits in the internal space of the main housing 10. A cooling fan 33 is provided on the rotating shaft 25 on the rear side of the motor 20. The fan 33 sucks outside air from wind windows 18 (see FIG. 2 to be described later for reference numerals) provided on both the left and right sides of the main housing 10 and flows the outside air from the front to the back in the rotation axis A1 direction, thereby causing the motor 20 and the circuit board. The electronic element mounted on the 30 is cooled. Air windows 64 (see FIG. 2 for reference numerals) and first through holes 65 are formed on the left and right side surfaces and the lower side surfaces of the rear cover 60, and most of the cooling air is external through the air windows 64. The rest is discharged into the body portion 11 of the main housing 10 through the first through hole 65. In order to allow inflow into the main housing 10, a protrusion 14 projecting rearward is formed in the main housing 10, and the first through hole 65 is a second through hole 15 formed in the protrusion 14 (the first through hole 15 is formed. Communicate with the inflow section). The air that has flowed into the protrusion 14 of the main housing 10 is exhausted to the outside through the wind window 19 formed in the body portion 11 of the main housing 10. The wind window 18 corresponds to the first intake unit in the present invention. Further, the wind window 19 corresponds to the second exhaust unit in the present invention.

In this way, the space for accommodating the motor 20 is defined by the main housing 10 and the rear cover 60, but the type of the motor 20 used is arbitrary. In FIG. 1, a brushless DC motor is used. Since the stator core 21 of the brushless motor 20 is held by the main housing 10, the rear cover 60 substantially holds the bearing 29 and functions to accommodate the fan 33.

The rotary shaft 25 of the motor 20 is connected to the reduction mechanism 40. The reduction mechanism 40 decelerates the output of the motor 20 at a predetermined reduction ratio and transmits it to the spindle 46, and here, it is a mechanism using planetary gears. The reduction mechanism 40 is provided in the space between the sun gear 41 fixed to the tip of the rotary shaft 25 of the motor 20, the ring gear 43 provided on the outer peripheral side of the sun gear 41 so as to surround the sun gear 41 at a distance, and the space between the sun gear 41 and the ring gear 43. It comprises a plurality of planetary gears 42 that are arranged and meshed with both of these gears. The ring gear 43 has a gear formed on the inner peripheral surface of the ring-shaped member, and is fixed to the main housing 10 via the inner cover 44. The sun gear 41 is a spur gear that serves as an input unit for the speed reduction mechanism 40. Since the three planetary gears 42 revolve around the sun gear 41 while rotating between the outer peripheral side gear surface of the sun gear 41 and the inner peripheral side gear surface of the ring gear 43, the spindle 46 having the function of a planetary carrier can be used. , Rotates in a decelerated state at a predetermined ratio.

The inner cover 44 is a component manufactured by integrally molding a synthetic resin, and is held by the body portion 11 of the main housing 10 so as to be sandwiched from the left-right direction. At this time, the inner cover 44 is held so as not to rotate relative to the main housing 10. The main role of the inner cover 44 is to hold the bearing 45 provided in the rotary impact mechanism and to hold the bearing 28 formed on the front side of the motor 20 to perform axial positioning. The bearing 45 held by the inner cover 44 is for axially supporting the rear end of the spindle 46, and for example, a ball bearing is used. The rotary striking mechanism 50 is configured to be sandwiched between the hammer case 3 and the inner cover 44 in order to suppress grease leakage, and the air flow around the motor 20 hardly flows to the deceleration mechanism 40 and the rotary striking mechanism 50 side. ..

A spindle cam groove 46a is formed on the outer peripheral surface of the spindle 46 integrally formed with the planetary carrier portion. The hammer 51 is arranged on the outer peripheral side of the shaft portion of the spindle 46, and a hammer cam groove 52 is formed on the inner peripheral side. The hammer 51 is held by a cam mechanism using a cam ball 47 that can move inside the spindle cam groove 46a and the hammer cam groove 52. The front side of the hammer spring 48 abuts on the hammer 51 side, and the rear side abuts on the planetary carrier portion of the spindle 46.

At the rear end of the anvil 55, two blade portions 56, which are impacted portions, are formed at positions separated by 180 degrees in the circumferential direction. The blade portion 56 has a shape extending outward in the radial direction, and is hit by the hitting claw of the hammer 51. The rotating body of the spindle 46 and the anvil 55 is pivotally supported by the inner wall of the hammer case 3 by the bearing 49 on the front side. The shapes of the hammer 51 and the blade portion 56 are arbitrary, and the number of the blade portions 56 may be three instead of two in the circumferential direction, or any other number.

The tip tool holding portion 35 is formed at two locations in the circumferential direction and has a hexagonal mounting hole 57 extending axially rearward from the front end portion of the anvil 55 and penetrates in the radial direction for arranging the steel ball 37. It is configured to include two holes to be formed and a sleeve 36 provided on the outer peripheral side. A spring 38 that urges the sleeve 36 to the rear side is mounted on the inside of the sleeve 36.

The rotational driving force of the motor 20 is transmitted from the rotary shaft 25 to the rotary impact mechanism 50 side via the reduction mechanism 40 using planetary gears. The reduction mechanism 40 transmits the output of the motor 20 to the spindle 46, and the revolution motion of the planetary gear 42 is converted into the rotational motion of the planetary carrier portion, and the spindle 46 rotates. When the spindle 46 rotates, the hammer 51 rotates accordingly, and the anvil 55 is rotated. While the load applied from the hammer 51 to the anvil 55 is small, the hammer 51 rotates so as to be substantially interlocked with the spindle 46. When the reaction force received from the tip tool becomes large, the cam ball 47 moves, causing the relative positions of the hammer 51 and the spindle 46 in the rotational direction to fluctuate slightly, and the relative positions of the hammer 51 and the spindle 46 in the rotational direction to be slightly. It fluctuates, and the hammer 51 retracts while compressing the hammer spring 48. The movement of the hammer 51 to the rear side is a movement while compressing the hammer spring 48.

Due to the backward movement of the hammer 51, the hitting claw of the hammer 51 gets over the blade portion 56 of the anvil 55 and the engagement between the two is released. Then, the hammer 51 is rapidly accelerated in the rotational direction and forward by the elastic energy stored in the hammer spring 48 and the action of the cam mechanism in addition to the rotational force of the spindle 46, and is forward by the urging force of the hammer spring 48. That is, it is moved to the anvil 55 side, and the striking claw of the hammer 51 reengages with the blade portion 56 of the anvil 55 and begins to rotate integrally. At this time, since a strong rotational striking force is applied to the anvil 55, the rotational striking force is transmitted to a tip tool (not shown) mounted on the anvil 55. After that, the same operation is repeated to tighten the screws and the like.

FIG. 2 is a partial side view of the main housing 10 of FIG. The main housing 10 has a front opening 11a for attaching the hammer case 3 to the front, and a rear opening 11b for attaching the rear cover 60 to the rear. The main housing 10 is a left-right split type with a vertical surface passing through the rotation axis A1 of the motor 20 as a split surface, and the left and right split pieces are fixed by a plurality of screws 17a to 17h (17e to 17h cannot be seen in the figure). .. The rear cover 60 has a cylindrical shape in which one end (front end) in the direction of the rotation axis A1 is formed by an opening surface 63, and the other end (rear end) is closed as a rear wall portion 62. be. The rear cover 60 is attached to the main housing 10 from the rear to the front in the direction of the rotation axis A1, and is fixed by a plurality of screws 71a to 71d (see FIG. 6) described later. On the side surface of the impact tool 1, a wind window (intake port) 18 for sucking in external air and a wind window (exhaust port) 64, 19 for discharging air are provided. The wind window 18 for sucking outside air is formed at substantially the same position as the circuit board 30 (see FIG. 1) when viewed in the direction of the rotation axis A1, and 12 small elliptical openings are formed in the vertical direction on the right side surface of the fuselage portion 11. It was formed. The opening group forming the wind window 18 is integrally formed at the time of molding the main housing 10, and communicates the internal space of the main housing 10 with the outside.

The rear cover 60 is manufactured by integrally molding a synthetic resin. The rear cover 60 has a cylindrical cylindrical portion 61, an opening surface 63 is formed on the front side of the cylindrical portion 61, and the rear side is a rear wall portion 62. A wind window 64 is formed on the right side surface of the cylindrical portion 61 of the rear cover 60. The wind window 64 is formed by a large number of slits elongated in the vertical direction, and these slits enable air to communicate with the internal space of the rear cover 60 and the outside. The wind window 64 is the third exhaust unit of the present invention. The wind window 64 is similarly formed not only on the right side surface of the cylindrical portion 61 but also on the left side surface. In the conventional impact tool 1, only the wind windows 64 formed on both the left and right sides function as exhaust ports. However, as the size of the main housing 10 becomes smaller, it becomes necessary to design the rear cover 60 as small as possible, so that the air volume cannot be sufficiently secured only by the size and number of slits that can be formed as the wind window 64. Therefore, in the present invention, the wind window, which was conventionally formed only on the left and right side surfaces of the cylindrical portion 61 of the rear cover 60, is formed on the upper surface or the lower surface of the cylindrical portion of the rear cover 60 to sufficiently increase the size and number of the wind windows as a whole. Secured in.

Regarding the idea of forming a wind window on the upper surface of the cylindrical portion of the rear cover 60, when the impact tool 1 falls on the floor or the like, or when the rear cover 60 collides with another object, the upper part of the rear end of the rear cover 60 is used. Since the probability of breakage is high, it is necessary to newly configure the strength near the upper part of the rear end to be sufficiently high. Since performing new processing in order to suppress damage leads to an increase in cost, it is preferable to form a wind window on the lower surface of the rear cover 60 rather than the upper surface of the cylindrical portion. In the hand tool of the type that does not provide the protruding portion 14, when the through hole 65 (first exhaust portion) is provided as a wind window on the lower surface of the cylindrical portion of the rear cover 60, the warm air discharged from the through hole 65 is discharged. In some cases, the operator's hand 110 that grips the hand-held tool is located. When the exhaust air directly hits the operator's hand in this way, it causes discomfort to the operator. Therefore, in this embodiment, the protrusion 14 is arranged between the through hole 65 (first exhaust portion) on the lower surface of the rear cover 60 and the worker's hand 110, and the through hole 65 (first exhaust portion) on the lower surface of the rear cover 60 is arranged. The exhaust gas discharged from the air is not suitable for the worker's hand 110. Whether or not the protrusion 14 is provided is determined by the temperature of the exhaust gas, the distance from the exhaust gas portion to the operator's hand 110, and the like.

In the lower portion of the rear cover 60, a protruding portion 14 extending rearward from the rear opening 11b of the fuselage portion 11 is provided. The protruding portion 14 is formed from the rear opening portion 11b of the body portion 11 to the rear end portion by the front-rear length L1 in the rotation axis A1 direction. On the other hand, the protruding portion 14 of the rear cover 60 is formed as a part of the body portion 11 of the main housing 10, and the wind window 19 which is the second exhaust port is formed on the side surface of the protruding portion 14. The front-back length in the rotation axis A1 direction is L. In this embodiment, L ₁ <L, and the rear cover 60 protrudes rearward from the protruding portion 14 by L ₂ minutes. However, if L ₁ ≤ L, the rear side of the protruding portion 14 The amount of extension to can be set arbitrarily. However, it is not preferable to make the relationship L ₁ > L because the rear end of the protruding portion 14 is more likely to hit another object and be damaged. The wind window 19 is provided on the side surface of the fuselage portion 11 of the main housing 10 near the rear end and near the handle portion 12.

It is desirable that the wind window 19 serving as the second exhaust portion is provided symmetrically with respect to the vertical surface passing through the rotation axis A1, but the installation location is such that the worker's hand 110 is not exposed to the wind and there is no problem in strength. If so, it may be arranged at any position on the main housing 10, may be arranged asymmetrically on the left and right sides of the main housing 10, and the size and number of wind windows may be arbitrary. The opening portion adjacent to the fan 33, such as the wind window 64, needs to be configured so that the wire or the like does not come into contact with the built-in fan 33 when the wire or the like is inserted. The wind window 19, the through hole 15, and the through hole 65 of the present invention have a labyrinth structure in their arrangement itself, so that foreign matter from the outside does not easily come into contact with the fan 33. Therefore, the wind window 19 may be formed into an oval shape (s) and the through holes 65 (1 piece) may be formed, or the wind window 19 may be formed into an oval shape (1 piece) and the through holes 65 may be formed into a grid shape (1 piece). Multiple) may be used. Further, if the size is such that the intrusion of a wire or the like can be prevented, the wind window 19 may be oval (1 piece) and the through hole 65 may be oval (1 piece). However, it is preferable to use one air passage for the through hole 15 whose outer circumference is surrounded by the bent portion 10c (see FIG. 3 described later for reference numerals) for convenience of molding. A wind window 19 is similarly formed on the left side surface of the impact tool 1.

FIG. 3 is an enlarged view of part A in FIG. The rear cover 60 is manufactured by two-layer molding, and an elastomer 60b having rubber characteristics is formed as an outer layer (or outer skin) on the inner resin portion 60a. The opening surface 63 of the rear cover 60 and the rear opening 11b of the main housing 10 are fitted in an inlay. That is, the opening edge portion 63a of the rear cover 60 is attached so as to be located outside the inner cylindrical portion 11c formed in the vicinity of the rear opening portion 11b of the main housing 10. In this way, since the rear cover 60 and the opening of the main housing 10 are connected so as to be in-row fitted, air leakage from the vicinity of the joint portion between the rear cover 60 and the main housing 10 can be prevented.

A through hole 65 penetrating from the inside to the outside in the radial direction is formed on the lower side surface of the rear cover 60. The through hole 65 corresponds to the first through hole of the present invention, and is a hole that communicates vertically with a part of the lower side surface 61b of the rear cover 60 to allow air to flow from the inside to the outside of the rear cover 60. It is possible. A through hole 15 that opens upward at the protrusion 14 is formed on the lower side of the through hole 65. By forming the protrusion 14 on the lower surface of the through hole 65, it is possible to prevent dust and needles from entering through the through hole 65. Therefore, the shape of the through hole 65 can be any shape such as a hole, a notch, or an opening.・ Size can be adopted. The larger the size of the through hole 65, the more the flow rate of the cooling air can be increased. The through hole 15 corresponds to the second intake portion of the present invention.

The main housing 10 also has a two-layer structure, and an elastomer 10b having rubber properties is formed as an outer layer (or outer skin) on the outer side of the inner resin portion 10a. At the lower end of the elastomer 60b of the rear cover 60, a bent portion 60c formed so as to be bent inward is formed. The elastomer 60b does not exist in the portion of the protrusion 14 facing the through hole 15 below the through hole 65. At the upper end of the elastomer 10b of the main housing 10, a bent portion 10c formed so as to be bent inward is formed. The bent portion 10c is configured to surround the outer periphery of the through hole 15, and the resin portion 10a is not formed inside the bent portion 10c in the horizontal direction, and the bent portion 10c is a large opening-shaped through hole 15. The outer edge of the through hole 15 seen in the horizontal direction is surrounded by the bent portion 10c by the elastomer 10b except for the front side, and the upper side of the bent portion 10c is the elastomer 60b bent to have substantially the same length. Will be in close contact. In this way, the elastomer 10b on the main housing 10 side and the elastomer 60b on the rear cover 60 side are in close contact with each other, thereby fulfilling a sealing function of closing the gap in the connection portion from the through hole 65 to the through hole 15. Further, due to the close contact between the bent portion 10c and the bent portion 60c, for example, the impact load transmitted from the rear cover 60 to the main housing 10 when the product is dropped can be attenuated, so that the durability of the impact tool 1 can be improved. ..

One or more through holes 65 are formed in a portion of the cylindrical portion of the rear cover 60 located on the lower side, and a part of the wind generated by the fan 33 flows into the projecting portion 14 side through the through holes 65. .. As described above, for example, the wind window 19 may be formed into a grid shape (s) and the through holes 65 may be formed into an oval shape (one piece), or the wind window 19 (second discharge portion) may be formed into an oval shape (1). The through holes 65 may be in the shape of a grid (s). Further, if the shape is small enough to prevent the intrusion of a wire or the like, the wind window 19 may be oval (1 piece) and the through hole 65 may be oval (1 piece). Since the through hole 15 on the protrusion 14 side is an opening of sufficient size, the air flowing through the through hole 65 does not leak and is formed inside the main housing 10, here as a part of the body portion 11. It will flow into the section 14. The wind window 19 corresponds to the second exhaust unit in the present invention.

The air that has flowed into the internal space of the protrusion 14 is discharged to the outside of the main housing 10 by three methods. The main discharge path is to discharge the air flowing in from the through hole 15 to the outside through the wind windows 19 formed on both the left and right sides of the protrusion 14. This exhaust path is a path shown as a dotted arrow F1 in FIG. As shown in FIG. 1, the wind window 19 is formed so as to be positioned so as not to interfere with the hand 110 holding the handle portion 12, that is, to be located above the hand holding the handle portion 12. The wind window 19 is an oval shape elongated in the front-rear direction, and is formed one on each of the right side surface and the left side side of the protrusion 14. The number of wind windows 19 (second exhaust sections) is not limited to one on each of the left and right sides, but the housing of the impact tool 1 (main housing 10, rear cover 60, hammer case 3) is downsized as in this embodiment. In the product pursuing the above, since the wind window 19 has to be arranged in a slight gap portion, in this embodiment, one is provided on each of the left and right side surfaces. In addition, when arranging the wind window 19, if it is too close to the opening surface of the screw boss 16d or the through hole 15, the local strength of the main housing 10 will decrease, so care must be taken.

The air that has flowed into the internal space of the protrusion 14 is discharged to the outside through the wind window 19, but can be discharged to the outside not only from the wind window 19 but also through a gap portion formed in the main housing 10. It is possible. Here, as shown by the dotted line arrow F2 in FIG. 1, it can be discharged to the outside through the gap portion of the through hole for the forward / reverse switching lever 7, and further, it is triggered as shown by the dotted line arrow F3 in FIG. It can be discharged to the outside through the gap portion of the opening for the lever 6a. The air volume of the dotted arrows F2 and F3 is actually small. However, the air volume of the dotted arrow F2 and F3 is adjusted by optimizing the size of the gap between the through hole for the forward / reverse switching lever 7 and the through hole for the trigger lever 6a formed in the main housing 10, or the shape of the air passage. It is possible to control. When the air by the fan 33 is discharged through the gap conventionally existing in the main housing 10 as shown by the dotted line arrows F2 and F3, consideration should be given so that the exhaust does not directly hit the worker's hand 110. is important. Therefore, it is preferable to arrange the position of the wind window 19 above the handle portion 12, or to discharge the wind window 19 in the horizontal direction or upward rather than in the horizontal direction when the air is discharged from the gap portion.

The sealing structure of the connecting air passage from the bottom of the rear cover 60 of the first embodiment described above to the inside of the protruding portion 14 of the main housing 10 is formed by the surface contact between the bent portion 10c by the elastomer 10b and the bent portion 60c by the elastomer 60b. In addition to the method of realizing it, it is also possible to realize it by other methods. FIG. 4 is a partially enlarged view showing modified examples 1 to 3 of the first embodiment of the present invention, and is a view corresponding to the part A of FIG. FIG. 4A shows that the lower end of the elastomer 60b is brought into contact with the bent portion 10c of the elastomer 10b on the main housing 10 side without forming the bent portion 60c shown in FIG. 3 on the rear cover 60 side. Here, the upper surface near the front end of the bent portion 10c is in contact with the elastomer 60b of the rear cover 60. At this time, if the thickness of the bent portion 10c is slightly larger than the distance between the opening surface of the through hole 15 and the peripheral surface of the through hole 65, the main housing 10 of the rear cover 60 as shown in FIG. 4 (A) can be used. Since the elastomer of the bent portion 10c is compressed in the vertical direction of the surface at the time of attachment to the rear cover 60, the sealing between the resin portion 60a of the rear cover 60 and the resin portion 10a of the main housing 10 is sufficiently maintained.

FIG. 4B does not form the bent portion of the elastomer 10b on the main housing 10 side, but forms the bent portion 60c only on the rear cover 60 side. Even with such a configuration, the lower surface of the bent portion 60c near the front end portion is in contact with the resin portion 10a of the main housing 10. At this time, if the thickness of the bent portion 60c is slightly larger than the distance between the opening surface of the through hole 15 and the peripheral surface of the through hole 65, the bent portion is formed when the rear cover 60 is attached to the main housing 10. Since the elastomer of 60c is compressed in the normal direction of the contact surface, the airtightness is sufficiently maintained.

In FIG. 4C, the bent portions 10c and 60c are formed on both the elastomer 10b of the main housing 10 and the elastomer 60b of the rear cover 60 as in the first embodiment, and the bent portions 10c and 60c are closely connected to each other. It is something that makes you. However, in this third modification, by forming the concave portion 60d and the convex portion 10d in the bent portions 10c and 60c, a so-called inlay fitting portion is formed in the joining between the bent portions by the elastomer. Further, a stepped portion 60e is formed on the resin portion 60a side to accommodate a part of the thickly formed bent portion 60c and the bent portion 10c. Although the shape of the resin portion 10a on the main housing 10 side is the same as that of the first embodiment, a rib-shaped convex portion 10d protruding upward is formed in the inner portion of the bent portion 10c. The convex portion 10d fits into the concave portion 60d formed in a concave shape inside the bent portion 60c. With this configuration, it is possible to maintain a high degree of adhesion at the joint surface between the rear cover 60 and the main housing 10.

As described above, even in the first to third modifications shown in FIG. 4, the same effect as in the first embodiment shown in FIGS. 1 to 3 can be achieved. The first to third modifications shown in FIG. 4 are all modifications in which the degree of sealing of the through hole 15 is improved by the bent portions 10c and 60c made of elastomers, or the convex portions 10d and the concave portions 60d. As long as the through hole 15 can serve as an air passage, not only a configuration using an elastomer but also any connection configuration between the main housing 10 and the rear cover 60 may be adopted.

FIG. 5 is a vertical cross-sectional view of the impact tool 1A according to the second embodiment of the present invention. In the second embodiment, as the air windows (second exhaust section) 19 formed in the main housing 10 in the first embodiment, in addition to the two air windows 19a on the left and right, the air window 19b on the rear side (see FIG. 6). ) Is formed. That is, the second exhaust section is composed of a total of four wind windows 19a and 19b. Other configurations are the same as in the first embodiment. In the figure of FIG. 5, the wind window 19b on the rear side cannot be seen due to the vertical cross-sectional position. A part of the air discharged from the fan 33, passing through the through holes 65 and 15 and flowing into the main housing 10 side is from the wind window 19b (see FIG. 6 below for the reference numeral) as shown by the dotted arrow F4. It is discharged to the rear side, and the rest is discharged from the wind window 19a to both the left and right sides of the impact tool 1. Further, air is discharged horizontally from the wind window 19a in both the left and right directions.

FIG. 6 is a rear view of the body portion 11 of the impact tool 1A of FIG. The rear cover 60 has the same shape as that of the first embodiment, and the rear cover 60 is fixed to the main housing 10 by four screws 71a to 71d oriented in a direction parallel to the rotation axis A1. The outer surface of the rear wall portion 62 of the rear cover 60 is flat, and an exhaust air window is not formed here. Wind windows 64 (see also FIG. 2) are formed on the left and right side surfaces of the rear cover 60. Here, when the rotation axis A1 is divided into four sections in the circumferential direction by 90 degrees each, the wind window 64 is formed on the right side surface portion and the left side surface portion of the cylindrical portion 61 of the rear cover 60. Is. Further, in a part of the lower portion of the cylindrical portion 61 of the rear cover 60, that is, within the range facing the protruding portion 14 of the main housing 10 (opposing range θ), the rear cover 60 has a through hole 65 (see FIG. 5 for reference numerals). Is formed. As described above, in the rear cover 60, by providing the through holes 65 on the surfaces other than the left and right side surfaces of the rear cover 60, it is possible to add an exhaust path such as the dotted line arrow F4 shown in FIG. 5 and the dotted line arrow F5 shown in the present figure. Therefore, the area of the exhaust port can be increased as compared with the conventional case. As the flow rate of the cooling air increases as the exhaust path increases, the cooling performance of the heat generating portion of the motor, the inverter circuit, or the like increases. In the first and second embodiments, the wind window (third exhaust portion) is not set in the upper portion of the cylindrical portion 61 of the rear cover 60, but if the strength of the rear cover 60 can be sufficiently secured, the rear cover is used. A wind window may be installed on the upper side surface of the 60.

FIG. 7 is a vertical cross-sectional view of the impact tool 1B according to the third embodiment of the present invention. In the first and second embodiments described above, the air that has flowed into the protrusion 14 of the main housing 10 through the through hole 65 is discharged to the outside through the discharge port or the gap formed on the main housing 10 side. Configured. In the third embodiment, the upper portion of the protruding portion 14 of the main housing 10 and the rear cover 60 are not brought into close contact with each other, but conversely, the upper portion of the protruding portion 14 of the main housing 10 and the cylindrical portion 61 of the rear cover 60 are separated from each other. A smaller gap was formed in the air, and air was exhausted into the atmosphere through the gap. Since the upper portion of the protrusion 14 is formed as a wall surface 14a instead of the through hole 15 as shown in FIG. 3, the air discharged from the rear cover 60 does not flow into the inside of the protrusion 14. In FIG. 7, as shown by the dotted arrow F6, the air discharged from the through hole 65 flows rearward along the upper surface of the wall surface 14a and is released into the atmosphere. Although the dotted arrow F6 is shown in FIG. 7 so as to flow only in the rear direction, the gap 8 extends in a direction of about 180 degrees from the opening of the through hole 65 in the left-right direction and diagonally backward. , Air is discharged so as to diffuse even toward the right side and the left side.

FIG. 8 is a rear view of the body portion 11 of the impact tool 1B of FIG. 7. The rear cover 60 has the same shape as that of the first and second embodiments, and is fixed to the main housing 10 with four screws 71a to 71d. An exhaust air window is not formed on the rear wall portion 62 of the rear cover 60, and air windows 64 (second through holes; see FIG. 2) are formed on the left and right side surfaces. A through hole 65 (see FIG. 7 for reference numerals) is formed in a part of the lower portion of the cylindrical portion 61 of the rear cover 60. The lower side surface 61b of the rear cover 60 is a horizontal surface in the left-right direction, and a minute gap 8 is formed between the rear cover 60 and the horizontal upper surface of the protrusion 14. The distance between the gaps 8 is constant except for the left and right peripheral edges.

9A and 9B are views of the impact tool 1C according to the first modification of the third embodiment of the present invention, FIG. 9A is a vertical sectional view passing through the rotation axis A1, and FIG. 9B is a rear view. Here, in order to improve the discharge efficiency from the gap 8, the gap 8 is formed so that the distance in the vertical direction becomes slightly larger as the gap 8 goes from the front to the rear, that is, the diameter is increased. In order to realize such a gap 8, the upper surface 14b of the protrusion 14 may be an inclined surface that slightly descends toward the rear, or the upper surface of the lower side surface 61b of the cylindrical portion of the rear cover 60 may be rearward. The slope should be slightly elevated as it goes, or both should be applied.

In FIG. 9B, the gap 8 is configured to be substantially horizontal in the left-right direction. Since the position of the worker's hand 110 is near the protrusion 14, the air passage is configured horizontally with respect to the left-right direction in order to prevent the wind from being discharged in the direction of the protrusion 14. The curved portion 61c was formed so that the distance in the left-right direction of the lower opposing surfaces of the curved portions 61c on both the left and right sides was shorter than the distance in the left-right direction of the upper surface 14b of the protruding portion 14. By forming the curved portions 61c on both the left and right sides in this way, the air discharged from the through hole 65 and flowing to the left or right on the upper surface 14b of the protruding portion 14 is above the upper surface 14b near the curved portion 61c. Since it is discharged into the atmosphere while diffusing in the direction, it becomes difficult for the exhaust air to hit the operator's hands.

As described above, in the first modification of the third embodiment, the gap 8 is formed between the rear cover 60 and the protrusion 14, and the gap 8 is formed so as to widen toward the rear. , The exhaust efficiency could be improved. Further, since the gap 8 is formed so as to increase in the rearward direction and the gap 8 becomes larger on the lower side of the curved portion 61c, the assembleability is improved when the rear cover 60 is assembled to the main housing 10. rice field.

10A and 10B are views of an impact tool 1D according to a second modification of the third embodiment of the present invention, FIG. 10A is a vertical cross-sectional view passing through the rotation axis A1, and FIG. 10B is a rear view. In FIG. 10, the upper surface of the protruding portion 14 of the rear cover 60 is formed as an inclined surface 14c that slightly rises toward the rear. This configuration is mainly intended to prevent foreign matter from entering the through hole through the gap without increasing the exhaust efficiency. Of the air exhausted from the through hole 65, the air flowing backward in the direction of the rotation axis A1 flows along the inclined surface 14c and is discharged into the atmosphere slightly diagonally upward at the trailing edge of the gap 8. .. As a result, the exhaust gas flows in the direction away from the hand, so that the exhaust air does not easily hit the operator's hand 110. Similar to the configuration of FIG. 9B, the configuration of FIG. 10B is such that the gap 8 is configured substantially horizontally in the left-right direction. Since the position of the worker's hand 110 is near the protrusion 14, the rear cover 60 is longer than the length of the inclined surface 14c, which is the lower surface in the left-right direction, in order to prevent the wind from being discharged in the direction of the protrusion 14. The length of the lower side surface in the left-right direction is shortened.

Although the present invention has been described above based on the examples, the present invention is not limited to the above-mentioned examples, and various modifications can be made without departing from the spirit of the present invention. For example, in FIG. 9B, the gap 8 serving as an air passage is configured to be substantially horizontal in the left-right direction, but the inclined surface 14 is angled in the left-right direction as a configuration in which the wind is not discharged to the worker's hand 110. May be provided so that the left and right sides are curved downward so as to be slightly upward from the horizontal direction. Further, for example, in a state where the left-right split type main housing is assembled, the upper surface of the protrusion 14 is configured to have a concave shape that is recessed downward, or the vertical cross section is formed to have a bow shape, so that the air can be discharged from the through hole 65. Since the air that has hit the upper surface of the protruding portion 14 flows along the slope of the upper surface of the protruding portion 14, the discharge direction can be changed slightly upward from the horizontal plane. Although the impact tool 1 has been described as an example of the working machine in the above embodiment, the working machine is not limited to the impact tool, and any working machine having a similar main housing and rear cover can be used. It can also be applied in.

1, 1A ~ 1D Impact tool 3 Hammer case 3a Through hole 5 Cover 6 Trigger switch 6a Trigger lever 7 Forward / reverse switching lever 8 Gap 10 Main housing 10a Resin part 10b Elastoma 10c Bent part 10d Convex part 11 Body part 11a Front opening 11b Rear opening 11c Inner cylindrical part 12 Handle part 13 Battery pack mounting part 14 Protruding part 14a Wall surface 14b, 14c Top surface (inclined surface) 15 Opening part (second intake part)
16a ~ 16h Screw boss 17a ~ 17h Screw
18 Wind window (1st intake section) 19, 19a, 19b Wind window (2nd exhaust section)
20 Motor 21 Stator Core 22 Coil 23 Rotor Core 24 Permanent Magnet 25 Rotating Shaft 28, 29 Bearing 30 Circuit Board 31 Hall IC 33 Fan 34 Control Circuit Board 35 Tip Tool Holder 36 Sleeve 37 Steel Ball 38 Spring 40 Deceleration Mechanism 41 Sun Gear 42 Planetary Gear 43 Ring gear 44 Inner cover 45 Bearing 46 Spindle 46a Spindle cam groove 47 Cam ball 48 Hammer spring 49 Bearing 50 Rotational impact mechanism 51 Hammer 52 Hammer cam groove 55 Anvil 56 Blade part 57 Mounting hole 60 Rear cover 60a Resin part 60b Elastoma 60c Folded part 60d (Elastoma) concave part 60e (resin part) stepped part 61 Cylindrical part 61b (cylindrical part) lower side surface 61c Curved part 62 Rear wall part 63 Opening surface 63a Opening edge part 64 Wind window (third exhaust part) ) 65 Through hole (1st exhaust part)
68 Bearing holder 71a-71d Screw 100 Battery pack 101 Latch button 110 (Worker's) Hand A1 Rotation axis

Claims (13)

The motor that drives the tip tool and
A main housing that accommodates at least a portion of the motor and has a fuselage that extends in the front-rear direction and opens rearward, and a rear cover that is connected to the opening.
A protrusion provided on the main housing and extending rearward from the opening,
A fan driven by the rotation of the motor and
A first intake unit provided on the body portion and taking in external air into the body portion by the fan, and a first intake unit.
It has a first exhaust unit provided on the rear cover and exhausts air taken in from the first intake unit by the fan.
A working machine characterized in that the first exhaust portion is provided on a side surface of the rear cover and a portion facing the protruding portion. The working machine according to claim 1, wherein the first exhaust unit is provided on the lower side surface of the rear cover. A handle portion to be gripped by an operator is provided below the main housing.
The working machine according to claim 1 or 2, wherein the protruding portion is provided on the lower side of the rear cover. A second intake portion is formed in the protruding portion at a position facing the first exhaust portion.
The air discharged from the first exhaust section flows into the main housing again from the second intake section, and the air flows into the main housing again.
The working machine according to claim 3, wherein the inflowing air is discharged to the outside through a second exhaust portion formed in the main housing. A third exhaust portion for discharging the air taken in from the first intake portion by the fan to the outside is formed on the left and right sides or the upper portion of the rear cover at a position not facing the protruding portion. The working machine according to any one of claims 1 to 4, wherein the working machine is characterized by the above. The working machine according to claim 4, wherein the second exhaust portion is provided on the protruding portion. An operation unit of a switch for activating the motor and a switching lever for switching the rotation direction of the motor are provided so as to be exposed from the inside to the outside of the main housing.
A part of the air taken in from the second intake unit is discharged to the outside through the gap between the operation unit and the main housing and / or the gap between the switching lever and the main housing. The working machine according to claim 4 or 6. The second exhaust portion is arranged above the handle portion of the main housing, and the air exhausted from the second exhaust portion is directed to a direction other than the operator's hand while holding the handle portion. The working machine according to claim 7, wherein the work machine is discharged from the air. At least a portion of the main housing and the rear cover is formed of an elastomer.
6. The working machine described in item 1. One of claims 7 to 9, wherein a gap is provided between the rear cover and the protruding portion, and the air discharged from the first exhaust portion is discharged into the atmosphere through the gap. The working machine described in. The working machine according to claim 10, wherein the gap is formed so as to open in the left-right direction or rearward. The working machine according to any one of claims 3 to 11, wherein the upper surface of the protruding portion has a concave shape or a bow shape. A battery pack mounting portion to which the battery pack can be attached and detached is provided at the lower end of the handle portion.
The working machine according to any one of claims 6 to 11, wherein the main housing is configured as a left-right split type and has the body portion, the handle portion, and the battery pack mounting portion.

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