JP2018122420A - Hand power tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hand power tool which has a new configuration without requiring an increase in the size of the device and impairing operability of the device when increasing in the size (increasing in the diameter) of a centrifugal fan to enhance cooling performance of a hand power tool.SOLUTION: In a hand power tool 10, a centrifugal fan 19 fixed to a motor shaft 32 provided in a motor 31 is arranged inside the vicinity of a connection portion of a motor case 12 and a gear case 13. A fan casing 35 which is provided with an opposing face 35a along a rear face of the centrifugal fan 19 and is fixedly installed in the vicinity of a front end of the motor case 12 is arranged on a rear face side of the centrifugal fan 19. An air flow guide surface which deflects an air flow directed radially outward to direct the front by rotation of the centrifugal fan 19 is constituted of the opposing face 35a of the fan casing 35, the front end face 12a of the motor case 12, and an inner peripheral surface 13a of the gear case 13.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a hand-held power tool, and more particularly to a hand-held power tool in which an outer peripheral portion of a motor storage portion in a motor case is configured as a grip portion that receives grip from an operator.

  Conventionally, a hand-held power tool using a motor such as a hand grinder or a hand drill as a drive source is known. In this type of hand-held power tool, the outer periphery of the motor case that houses the motor is configured as a gripping part that is gripped by the operator, and therefore, it is required to efficiently cool the motor that is a heat source. It was. Therefore, in order to air-cool the motor as a heat source, a centrifugal fan is fixedly installed on the motor shaft of the motor, and the motor is cooled by an air flow generated by the centrifugal fan. In addition, in order to distribute the airflow effectively, a fan casing having a shape along the shape of the centrifugal fan is arranged in the vicinity of the centrifugal fan, and an efficient airflow is realized by the action of the shape of the fan casing. It was done.

  In the conventional hand-held power tool, for example, as disclosed in Patent Documents 1 and 2 below, the fan casing is formed in a substantially bowl shape having an opening at the center position, and from the rear surface of the centrifugal fan. It was arrange | positioned so that an outer periphery might be enclosed. The surface surrounding the centrifugal fan of the fan casing is an airflow guide surface that guides the airflow, and the airflow that is generated by the centrifugal fan is deflected forward by the airflow guide surface. It becomes. Furthermore, the airflow guide surface is composed of a surface along the rear surface (a rear edge) of the centrifugal fan blade and a surface extending forward from the surface.

Japanese Patent No. 4416192 JP 2002-18745 A

  By the way, a centrifugal fan installed in a hand-held power tool is for generating a flow of cooling air for cooling a motor or the like that is a heat generation source. ing. However, in the conventional hand-held power tools represented by the above-mentioned Patent Documents 1 and 2, simply increasing the size (increasing diameter) of the centrifugal fan in order to increase the cooling performance leads to an increase in the size of the device. As a result, there is a problem that the operability of the handheld power tool is lowered.

  The present invention has been made in view of the problems existing in the above-described prior art, and its purpose is to increase the size (increase in diameter) of a centrifugal fan in order to improve the cooling performance of a hand-held power tool. Another object of the present invention is to provide a hand-held power tool having a new configuration that does not require an increase in the size of the apparatus and does not impair the operability of the hand-held power tool.

  The present invention will be described below. In addition, in order to make an understanding of this invention easy, the reference number of an accompanying drawing is attached in parenthesis writing, However, This invention is not limited to the form of illustration.

  A hand-held power tool (10, 100) according to the present invention is connected to a motor case (12) that houses a motor (31) serving as a drive source, and a front end of the motor case (12). A gear case (13) that houses driving force transmission means comprising a plurality of gears that decelerate the rotational driving force from the motor (31), and rotation from the motor (31) that is transmitted via the driving force transmission means. A rotating tool (21) that rotates by receiving a driving force, and an outer peripheral portion of a storage portion of the motor (31) in the motor case (12) is configured as a gripping part that receives gripping from an operator. In the hand-held power tool (10, 100), a motor shaft (3) included in the motor (31) is provided in the vicinity of the connection portion between the motor case (12) and the gear case (13). The centrifugal fan (19) fixed to the centrifugal fan (19) is disposed on the rear surface side of the centrifugal fan (19), and is provided with opposing surfaces (35a, 135a) along the rear surface of the centrifugal fan (19). A fan casing (35, 135) fixedly installed in the vicinity of the front end of (12) is disposed, and an airflow that deflects an airflow that is directed outward in the radial direction forward by rotation of the centrifugal fan (19). The guide surface includes the facing surface (35a, 135a) of the fan casing (35, 135), the front end surface (12a) of the motor case (12), and the inner peripheral surface (13a) of the gear case (13). It is characterized by comprising.

  In the hand-held power tool (10, 100) according to the present invention, the front end surface (12a) of the motor case (12) is an outer periphery of the facing surface (35a, 135a) of the fan casing (35, 135). It can be arranged on the extended surface on the side.

  Furthermore, in the hand-held power tool (10, 100) according to the present invention, the inner peripheral surface (13a) of the gear case (13) is disposed so as to surround the outer periphery of the centrifugal fan (19). can do.

  Furthermore, in the hand-held power tool (10, 100) according to the present invention, the outer peripheral edge of the facing surface (35a, 135a) of the fan casing (35, 135) is the front end of the motor case (12). It can be assumed that it is arranged to be fitted to the inner peripheral surface of.

  According to the present invention, when the centrifugal fan is increased in size (increase in diameter) in order to improve the cooling performance of the handheld power tool, it is not necessary to increase the size of the device, and the operability of the handheld power tool is improved. It is possible to provide a hand-held power tool having a new configuration that is not damaged.

It is a figure for demonstrating the external appearance structure of the hand-held power tool which concerns on this embodiment, the division figure (a) in a figure is a right side view, a division figure (b) is a top view, and a division figure (c) Shows the front view. It is the figure which made the cross section the part of the position shown by AA in the fractional drawing (a) in FIG. It is the figure which made a part of the position shown by BB in the sectional view (b) in FIG. It is the longitudinal cross-section front view showing the EE cross section in FIG. It is the longitudinal cross-section front view showing the FF cross section in FIG. It is a longitudinal cross-section right side view showing the principal part of CC cross section shown in the fractional drawing (b) in FIG. It is the longitudinal cross-section right side view showing the principal part of DD cross section shown in the fractional drawing (b) in FIG. It is the perspective view which showed the external appearance of the motor case which the hand-held power tool which concerns on this embodiment has, and the partial figure (a) in a figure is an external perspective view when it sees from the front upper side, ) Is an overview perspective view when viewed from the front lower side. It is a figure for demonstrating the shape of the fan casing which the hand-held power tool which concerns on this embodiment has, The fractional view (a) in a figure shows front view, The fractional view (b) shows left view, The partial diagram (c) shows a GG section in the partial diagram (a). It is the perspective view which showed the external appearance structure of the fan casing which concerns on this embodiment, and the fractional figure (a) in a figure is the perspective view seen from the back side, and the case where the partial figure (b) is seen from the front side It is a perspective view. It is a figure which shows an example among the various modifications of the fan casing applicable to this invention, and is a principal part enlarged view of the figure corresponding to FIG. 3 of this embodiment especially. It is a figure which shows an example among the various modifications of the fan casing applicable to this invention, and is a figure corresponding to FIG. 6 of this embodiment especially.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  First, the external configuration of the handheld power tool 10 according to the present embodiment will be described with reference to FIG. Here, FIG. 1 is a diagram for explaining the external configuration of the hand-held power tool according to the present embodiment, in which a partial view (a) is a right side view and a partial view (b) is a top view. The partial diagram (c) shows a front view. In the following description, for convenience of description, a direction corresponding to the usage state of the handheld power tool 10 is defined. That is, as shown in FIG. 1, the side on which the grindstone 21 that is a rotary tool is installed is “front”, the side on which the power cord 41 is installed is “rear”, and the partial diagram (b) in FIG. The upper side of the drawing is “left”, the lower side of the drawing in FIG. 1B is “right”, the upper side of the drawing in FIG. 1A is “up”, and the drawing in FIG. The lower side of the sheet in FIG. In addition, the direction defined in this specification does not limit the use direction of the handheld power tool 10 according to the present embodiment, and the handheld power tool 10 according to the present embodiment can be used in any posture direction. It is.

  As shown in FIG. 1, a hand-held power tool 10 according to this embodiment is configured as a hand-held portable grinder, and performs a grinding operation with a housing 11 formed to extend in the longitudinal direction. And a disk-shaped grindstone 21 that is a rotating tool for the purpose.

  The housing 11 receives a rotational driving force from the motor case 12 as a casing that houses therein a motor 31 (details will be described later) serving as a driving source, and transmits the rotational driving force to the grindstone 21. A gear case 13 that houses a driving force transmission means composed of a plurality of gear groups, a power cord 41 for supplying power to the motor 31, a power supply device such as a switch box, and a motor 31 for controlling the operation of the motor 31. And a tail case 14 as a casing in which a control board and the like are accommodated.

  The motor case 12 is made of a metal member such as resin or aluminum alloy, and the outer peripheral portion of the motor storage portion in the motor case 12 is configured as a grip portion that receives grip from the operator. Further, the outer shape of the motor case 12 is formed in a substantially cylindrical shape so that the operator can easily grasp it.

  The gear case 13 connected to the front side of the motor case 12 is made of a metal member such as an aluminum alloy. And the grindstone 21 as a rotary tool which will perform grinding work is arrange | positioned in the lower part of this gear case 13, and the chip etc. do not scatter to an operator on the back side of the grindstone 21. In order to achieve this, a safety cover 22 is installed.

  The tail case 14 connected to the rear side of the motor case 12 is made of resin. The tail case 14 has a large number of opening holes 15 at the left and right positions, and is configured to take in external air from the opening holes 15 and to air-cool the members inside the tail case 14. A power cord 41 for supplying power from an external power source (not shown) to the motor 31 can be installed behind the tail case 14.

  The external configuration of the hand-held power tool 10 according to the present embodiment has been described above using FIG. Next, the internal configuration of the hand-held power tool 10 according to the present embodiment will be described by adding FIGS. 2 to 7 to the reference drawings. Here, FIG. 2 is a cross-sectional view of a part of the position indicated by AA in the partial diagram (a) in FIG. FIG. 3 is a cross-sectional view of a part of the position indicated by BB in the partial diagram (b) in FIG. Further, FIG. 4 is a longitudinal sectional front view showing an EE section in FIG. 3, and FIG. 5 is a longitudinal sectional front view showing an FF section in FIG. Further, FIG. 6 is a right side view of the longitudinal section showing the main part of the CC cross section shown in the partial view (b) in FIG. 1, and FIG. 7 is a partial view (b) in FIG. It is a longitudinal cross-section right view showing the principal part of the DD cross section shown.

  Among the drawings illustrating the internal structure of the hand-held power tool 10 according to the present embodiment, as shown in FIGS. 2 and 3 in particular, a drive source for driving the grindstone 21 is provided inside the motor case 12. The motor 31 is arranged so that the axis of the motor shaft 32 substantially overlaps the axis of the substantially cylindrical motor case 12. Further, the front end portion 32 a of the motor shaft 32 protrudes from the motor case 12 into the gear case 13 and is supported by a front bearing 17 installed in the gear case 13. On the other hand, the rear end portion 32 b of the motor shaft 32 is supported by the rear bearing 18 at the rear portion of the motor case 12. Therefore, the motor shaft 32 is configured to be able to rotate at a high speed by supporting both end portions 32a and 32b by the front and rear bearings 17 and 18.

  The centrifugal fan 19 is fixed to the motor shaft 32 at a position behind the front bearing 17 in the vicinity of the front end portion 32a of the motor shaft 32 and in the vicinity of the location where the motor case 12 and the gear case 13 are connected. Has been installed. The centrifugal fan 19 plays a role of passing cooling air through the interior of the motor case 12 by being arranged at a position in the vicinity of the location where the motor case 12 and the gear case 13 are connected. Therefore, when the centrifugal fan 19 rotates together with the motor shaft 32, outside air is taken into the motor case 12 to generate cooling air, which cools the motor 31 and the like through the gap in the motor case 12. Then, it passes through the gear case 13 and is discharged from the front of the hand-held power tool 10 to the outside of the machine.

  Note that the motor 31 of the hand-held power tool 10 according to the present embodiment is configured as a brushless motor. Therefore, a control board or the like for controlling the operation of the motor 31 is disposed inside the tail case 14 connected to the rear of the motor case 12. And the inside of the tail case 14 is also cooled by the cooling air introduced by the action of the centrifugal fan 19 described above.

  In the gear case 13, a small bevel gear 23 fixed to the front end portion 32 a of the motor shaft 32 and a large bevel gear 24 that meshes with the small bevel gear 23 are housed. The bevel gear 24 is fixed to a drive shaft 27 that is vertically supported in the gear case 13 via bearings 25 and 26, and the drive shaft 27 protrudes below the gear case 13, and a grindstone is formed at the protruding portion. 21 is detachably fixed. The members such as the small bevel gear 23, the large bevel gear 24, and the drive shaft 27 function as drive force transmission means, so that when the motor 31 rotates, the rotational drive force is transmitted from the motor shaft 32 to the small bevel gear 23 and the large bevel. Since it is transmitted to the gear 24 and finally the grindstone 21 rotates via the drive shaft 27, it is possible to perform grinding on the workpiece.

  Further, an on / off switch (not shown) and other power supply devices are housed in the tail case 14, and the motor 31 rotates or stops when the operator switches the on / off switch. The power tool 10 can be operated. Further, in the hand-held power tool 10 according to the present embodiment, the operator can adjust the rotation speed of the motor 31 by operating a motor rotation speed control dial (not shown) after turning on the on / off switch. It is possible. Therefore, when the operator holds the motor case 12 with one hand and turns the on / off switch on with the finger of the other hand, the motor 31 rotates and moves from the motor shaft 32 to the small bevel gear 23 and the large bevel gear 24. Power is transmitted and the grindstone 21 rotates. Further, when the operator operates a motor rotation number control dial (not shown), the rotation number of the motor 31 is changed, and the rotation condition of the grindstone 21 corresponding to the workpiece is adjusted. Thereby, suitable grinding processing can be performed on the workpiece. At this time, since the centrifugal fan 19 rotates simultaneously with the rotation of the motor shaft 32, the outside air is taken into the housing 11, that is, the tail case 14, the motor case 12, and the gear case 13. Since this outside air cools the control board in the tail case 14 and the heat source such as the motor 31 in the motor case 12, it passes through the motor case 12 and is discharged from the front side of the gear case 13 to the outside of the machine. Thus, the operation of the safe and stable hand-held power tool 10 is realized. When the grinding operation is completed and the operator turns off the on / off switch, the motor 31 stops and the grindstone 21 stops rotating.

  The basic configuration of the handheld power tool 10 according to the present embodiment has been described above, but the handheld power tool 10 according to the present embodiment has further significant features. Therefore, in addition to the reference drawings of FIGS. 8 to 10, the characteristic configuration of the hand-held power tool 10 according to the present embodiment will be further described. Here, FIG. 8 is a perspective view showing an external shape of a motor case included in the hand-held electric tool according to the present embodiment, and an external perspective view when the partial view (a) in the drawing is viewed from the front upper side. FIG. 5 is a perspective view of the partial view (b) as viewed from the front lower side. Moreover, FIG. 9 is a figure for demonstrating the shape of the fan casing which the hand-held power tool which concerns on this embodiment has, The fractional view (a) in a figure shows a front view, The fractional view (b) A left side view is shown, and a partial view (c) shows a GG cross section in the partial view (a). Further, FIG. 10 is a perspective view showing an external configuration of the fan casing according to the present embodiment, where a partial view (a) in the drawing is a perspective view seen from the back side, and a partial view (b) is a front view. It is a perspective view at the time of seeing from the side.

  As shown in detail in FIG. 6 and FIG. 7, the rear surface side of the centrifugal fan 19 in the hand-held power tool 10 according to the present embodiment is provided with a facing surface 35 a along the rear surface of the centrifugal fan 19 so that the centrifugal fan 19 is centrifuged. A fan casing 35 that guides the airflow generated by the fan 19 is disposed. The fan casing 35 according to the present embodiment is a member that is attached to the front end portion of the motor case 12, and the configuration for attaching both members is shown in detail in FIGS.

  First, as shown in FIG. 8, the motor case 12 is a substantially cylindrical member, and four locking holes 12b as locked portions are formed in the vicinity of the front end surface 12a of the motor case 12. ing. On the other hand, as shown in FIGS. 9 and 10, the fan casing 35 is formed with four locking claws 35 b as locking portions, and these four locking claws 35 b are formed on the motor case 12. It arrange | positions in the position corresponding to the four latching holes 12b. Therefore, by inserting the fan casing 35 from the front end opening of the motor case 12 and engaging the four locking claws 35b with the corresponding four locking holes 12b, respectively, the front end of the motor case 12 is engaged. The fan casing 35 can be fixed and installed easily and reliably.

  Further, two convex key members 12c are formed on the inner peripheral surface of the front end portion of the motor case 12, and two key grooves corresponding to the two key members 12c are formed in one fan casing 35. 35c is formed. Therefore, when the four locking claws 35b are respectively engaged with the corresponding four locking holes 12b, the two key members 12c and the two key grooves 35c are fitted, so that the front end portion of the motor case 12 is engaged. Positioning of the fan casing 35 is executed, and the fan casing 35 can be easily and accurately attached to the front end portion of the motor case 12.

  Further, as shown in FIG. 6 and FIG. 7, in the present embodiment, the outer peripheral edge of the facing surface 35 a of the fan casing 35 is configured to be fitted to the inner peripheral surface of the front end portion of the motor case 12. Has been. Therefore, the engagement of the four locking claws 35b with the four locking holes 12b on the rear side and the fitting of the outer peripheral edge of the facing surface 35a to the inner peripheral surface of the front end portion of the motor case 12 on the front side, The stable attachment state of the casing 35 can be maintained.

  Further, the fan casing 35 according to the present embodiment is attached only to the motor case 12 and is configured to be housed and accommodated with respect to the inner peripheral surface of the front end portion of the motor case 12. Furthermore, the mounting of the motor case 12 and the gear case 13 is realized by tightening the nut 34 located on the outer peripheral surface in a state where the front end portion of the motor case 12 and the rear end portion of the gear case 13 are in contact with each other. When the motor case 12 and the gear case 13 are attached, the fan casing 35 is not involved. Therefore, according to the configuration of the present embodiment, there is no need to consider the accumulated error of the constituent members as in the above-described conventional technology. Therefore, when the fan casing 35 is installed on the hand-held power tool 10, the manufacturing cost is reduced. It is possible to provide a hand-held power tool 10 that can be easily manufactured while maintaining the performance as a power tool.

  Furthermore, with respect to the fan casing 35 according to the present embodiment, as shown in FIGS. 6 and 7, the opposing surface 35 a that is the front surface of the fan casing 35 is upstream from the outer peripheral edge side toward the center direction in the longitudinal sectional view. The rear surface 35d of the fan casing 35 has an inclined surface that is inclined toward the downstream side (front side) from the outer peripheral edge side toward the center direction in a longitudinal sectional view. It is configured. That is, the fan casing 35 according to the present embodiment has a wedge shape in a longitudinal sectional view, as shown in more detail in the partial view (c) of FIG. Therefore, when the airflow conducted from the inside of the motor case 12 is guided toward the front of the gear case 13, the wedge shape guides the airflow without stagnation, so that the airflow generated by the action of the centrifugal fan 19 is efficiently generated. By flowing, it is possible to obtain a more effective cooling effect.

  In the fan casing 35 according to the present embodiment, as shown in FIGS. 9 and 10, the four locking claws 35b are integrally projected from the outer peripheral portion of the rear surface 35d toward the upstream side (rear side). Has been. Therefore, the structure can be manufactured at low cost. Similarly, two leg portions 35e are formed at positions aligned with the four locking claws 35b. The leg portion 35e faces the stator of the motor 31 fixedly installed in the motor case 12 with a slight gap. Thereby, it is possible to prevent the fixing position of the stator of the motor 31 with respect to the motor case 12 from being greatly shifted to the gear case 13 side.

  Furthermore, as shown in FIGS. 6 and 7, in the present embodiment, as described above, the rear surface side of the centrifugal fan 19 is provided with a facing surface 35a along the rear surface of the centrifugal fan 19 and a motor case. A fan casing 35 that is fixedly installed in the vicinity of the front end portion of 12 is disposed. Then, the air flow directed outward in the radial direction by the rotation of the centrifugal fan is directed forward by the three surfaces of the facing surface 35a of the fan casing 35, the front end surface 12a of the motor case 12, and the inner peripheral surface 13a of the gear case 13. The air flow guide surfaces (35a, 12a, 13a) to be deflected are configured. Further, the front end surface 12 a of the motor case 12 is disposed on an outer peripheral surface of the facing surface 35 a of the fan casing 35. That is, the three surfaces of the facing surface 35a of the fan casing 35 constituting the airflow guide surface (35a, 12a, 13a), the front end surface 12a of the motor case 12, and the inner peripheral surface 13a of the gear case 13 are substantially continuous. Since the surface is configured without a step, the airflow generated by the rotation of the centrifugal fan 19 is not disturbed when flowing along the airflow guide surface (35a, 12a, 13a), and the airflow guide surface (35a, 12a, 13a). ) To flow smoothly.

  In the present embodiment, the inner peripheral surface 13 a of the gear case 13 is arranged so as to surround the outer periphery of the centrifugal fan 19. That is, since the outer peripheral side of the centrifugal fan 19 is surrounded by the inner peripheral surface of the gear case 13 on the outer side, there is no fan casing or housing (motor case) as in the prior art. Yes. That is, since there are few members that hinder the enlargement (large diameter) of the centrifugal fan 19 on the outer peripheral side of the centrifugal fan 19, the enlargement (large diameter) of the centrifugal fan 19 can be easily executed. Yes.

  Since it has the structure demonstrated above, in order to improve the cooling performance of the handheld electric tool 10 by providing the structure with the airflow guide surface (35a, 12a, 13a), the handheld electric tool 10 which concerns on this embodiment. When enlarging the centrifugal fan 19 (increasing the diameter), it is not necessary to increase the size of the device, and the operability of the device is not impaired.

  Further, in the present embodiment, the fan casing 35 is not formed so as to extend to the outer peripheral side of the centrifugal fan 19 unlike the fan casing of the prior art, so that the fan casing 35 is reduced in size in the radial direction and the axial direction. Can do. Therefore, the weight reduction of the fan casing 35 is facilitated.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment.

  For example, in the fan casing 35 according to the above-described embodiment, as shown in FIGS. 6 and 7, the facing surface 35a that is the front surface of the fan casing 35 is upstream from the outer peripheral edge side toward the center direction in the longitudinal sectional view. The rear surface 35d of the fan casing 35 is inclined toward the downstream side (front side) from the outer peripheral edge side toward the center in the longitudinal sectional view. It was configured with. However, the form that the fan casing according to the present invention can take is not limited to the above-described embodiment. The fan casing according to the present invention can take various modified forms within a range in which the above-described effects can be exhibited. For example, FIGS. 11 and 12 are views showing an example of various modified embodiments of the fan casing applicable to the present invention. In particular, FIG. 11 is a diagram corresponding to FIG. 3 of the present embodiment. FIG. 12 is a view corresponding to FIG. 6 of the present embodiment. As illustrated in FIGS. 11 and 12, the rear surface 135d of the fan casing 135 according to the modified example is a longitudinal section. It can be configured to have an inclined surface that is inclined in the upstream direction (rear side) from the outer peripheral edge side toward the center direction when viewed. Even when the fan casing 135 having such a shape is employed, a hand-held power tool 100 that can be easily manufactured while maintaining performance as a power tool without increasing the manufacturing cost is provided. Is possible. Note that the handheld power tool 100 according to the modified example also has a configuration of an airflow guide surface (opposing surface 135a, front end surface 12a, inner peripheral surface 13a), so that the cooling performance of the handheld power tool 100 is improved. Therefore, when the centrifugal fan 19 is increased in size (increase in diameter), it is not necessary to increase the size of the device, and the operability of the device is not impaired.

  It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  10,100 Hand-held power tool, 11 Housing, 12 Motor case, 12a Front end surface, 12b Locking hole, 12c Key member, 13 Gear case, 13a Inner peripheral surface, 14 Tail case, 15 Open hole, 17 Front bearing, 18 Rear bearing, 19 Centrifugal fan, 21 Grinding wheel, 22 Safety cover, 23 Small bevel gear, 24 Large bevel gear, 25, 26 Bearing, 27 Drive shaft, 31 Motor, 32 Motor shaft, 32a Front end, 32b Rear end, 34 Nut, 35, 135 Fan casing, 35a, 135a Opposing surface, 35b Locking claw, 35c Keyway, 35d, 135d Rear surface, 35e Leg, 41 Power cord.

Claims (4)

A motor case that houses a motor serving as a drive source;
A gear case that is connected to the front end portion of the motor case and houses driving force transmission means composed of a plurality of gears that decelerate the rotational driving force from the motor;
A rotary tool that rotates and receives a rotational driving force from the motor transmitted through the driving force transmitting means;
An outer peripheral portion of the motor storage portion in the motor case is a hand-held power tool configured as a gripping part that receives gripping from an operator,
A centrifugal fan fixed to the motor shaft of the motor is disposed in the vicinity of the connection portion between the motor case and the gear case,
On the rear surface side of the centrifugal fan, a fan casing provided with a facing surface along the rear surface of the centrifugal fan and fixedly installed near the front end portion of the motor case is disposed.
An airflow guide surface that deflects an airflow that is directed radially outward by the rotation of the centrifugal fan toward the front, the opposed surface of the fan casing, a front end surface of the motor case, and an inner peripheral surface of the gear case A hand-held power tool characterized by comprising The hand-held power tool according to claim 1,
The front end surface of the motor case is disposed on an extended surface on the outer peripheral side of the facing surface of the fan casing. The hand-held power tool according to claim 1 or 2,
A hand-held power tool, wherein an inner peripheral surface of the gear case is disposed so as to surround an outer periphery of the centrifugal fan. In the hand-held power tool according to any one of claims 1 to 3,
A hand-held power tool, wherein an outer peripheral edge of the facing surface of the fan casing is arranged to be fitted to an inner peripheral surface of a front end portion of the motor case.

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