power tools

Abstract

To obtain high cooling efficiency by securing a wide aperture area of an exhaust port even when a lock mechanism of a spindle is provided in a head housing.SOLUTION: A grinder 1 includes: a body housing 1a for housing a motor and a fan; a gear housing 4 connected to a front side of the body housing 1a; and a spindle and a lock mechanism 45 housed in the gear housing 4. The gear housing 4 is formed from a gear housing part 26 for housing the spindle and the lock mechanism 45, and a connection part 25 connected to the body housing 1a. The lock mechanism 45 is arranged in a central region in a left-right direction of the gear housing 4, and a lateral width of the gear housing part 26 is formed smaller than a lateral width of the connection part 25. Side exhaust ports 27, 27 for discharging cooling air for the motor generated by rotation of the fan are formed on left and right sides of the gear storage part 26, respectively, in the front face of the connection part 25.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to power tools such as grinders that use a motor as a power source.

Background Art

[0002] For example, a grinder has a spindle that rotates by motor drive, and a tip tool such as a disc-shaped grindstone is attached to the tip of the spindle that protrudes downward from the housing. Therefore, polishing work and the like can be performed with the tip tool that rotates together with the spindle. In such a grinder, it is necessary to lock the rotation of the spindle when attaching and detaching the tip tool. For example, in Patent Document 1, a gear housing (head housing) that houses a spindle and bevel gears is provided at the front part of a main body housing that houses a motor, and a shaft lock (locking mechanism) is provided in the gear housing. When this shaft lock is pushed into the gear housing, the tip of the shaft lock engages with a recess provided in a bevel gear integrated with the spindle, thereby locking the rotation of the spindle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The shaft lock of the above Patent Document 1 is arranged closer to the right side of the gear housing. Therefore, the left-right width of the housing portion that houses the spindle and bevel gears becomes wider, and the left-right width becomes substantially the same as the connecting portion with the main body housing. Therefore, when a fan for cooling the motor is provided in the main body housing, the exhaust port for the cooling air of the motor to be opened in the gear housing can only be arranged above and below the housing portion. For this reason, it has been difficult to secure the opening area of the exhaust port and improve the cooling efficiency of the motor.

[0005] Therefore, the present disclosure aims to provide a power tool that can secure a wide opening area for the exhaust port even when a spindle locking mechanism is provided in the head housing, thereby achieving high cooling efficiency. [Means for solving the problem]

[0006] To achieve the above objective, this disclosure relates to a power tool, The output shaft is positioned facing forward. It houses the motor and the fan for cooling the motor. and extends in the front-to-back direction The main housing and The head housing is connected to the front of the main housing, Housed in the head housing The axis is positioned in the vertical direction. , a spindle with a detachable tip tool, It includes a locking mechanism housed in the head housing that allows the rotation of the spindle to be locked at will, The head housing is formed from a housing portion that accommodates the spindle and locking mechanism, and a connecting portion that connects to the main body housing. And the locking mechanism is, Between the spindle axis and the connecting part and The head housing is characterized by being positioned in the central region in the left-right direction, with the width of the housing portion being smaller than the width of the connecting portion, and having an exhaust port formed on at least one side of the housing portion on the front of the connecting portion to discharge the cooling air from the motor generated by the rotation of the fan. In this disclosure, the term "central region in the left-right direction" includes not only the exact center in the left-right direction, but also cases where there is an error that causes a deviation to the left or right from the center. [Effects of the Invention]

[0007] According to this disclosure, even with a spindle locking mechanism in the head housing, a wide opening area for the exhaust port can be secured, resulting in high cooling efficiency. Furthermore, the compact size of the housing allows for work in relatively confined spaces, and visibility during operation is also improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a grinder. [Figure 2] This is a plan view of the grinder. [Figure 3] Figure 2 shows an enlarged cross-sectional view of the area along line AA (the locking member is in the unengaged position). [Figure 4] Figure 2 is an enlarged cross-sectional view of the BB line. [Figure 5] Figure 3 is a cross-sectional view along the CC line. [Figure 6] This is an exploded perspective view of the gear housing and locking mechanism. [Figure 7] This is an enlarged cross-sectional view corresponding to Figure 3, where the locking member is in the engagement position. [Figure 8] Figure 7 is a cross-sectional view of the DD line. [Modes for carrying out the invention]

[0009] In one embodiment of this disclosure, the exhaust ports may be formed on both the left and right sides of the housing. This configuration allows for a balanced arrangement of exhaust vents, ensuring a large opening area and improving cooling efficiency. In one embodiment of this disclosure, the exhaust port may also be formed on at least one of the upper and lower sides of the housing portion on the front surface of the connecting portion. This configuration allows for a larger opening area for the exhaust port. In one embodiment of the present disclosure, the spindle is positioned with its axis oriented vertically, and the locking mechanism may be positioned between the axis of the spindle and the connecting portion. This configuration allows the locking mechanism to be placed in the central area in the left-right direction, while keeping the height of the upper end of the storage compartment low, thus ensuring good visibility during operation. In one embodiment of the present disclosure, the motor is arranged with its output shaft facing in the front-rear direction, and the vertical distance from the axis of the output shaft to the upper end of the housing portion may be less than or equal to half the vertical distance from the axis of the output shaft to the upper end of the connecting portion. According to this configuration, the upper end height of the housing portion can be suppressed to be lower, and further improvement in visibility can be expected.

[0010] In one embodiment of the present disclosure, the housing portion and the connecting portion may be integrally formed as a single member. According to this configuration, the structure is simplified and the number of parts is reduced. In one embodiment of the present disclosure, the housing portion may be made of metal and its surface may be covered with resin. According to this configuration, while ensuring the rigidity of the housing portion, the operator's hand will not directly touch the housing portion. Therefore, the feel when operating the locking mechanism is improved. In one embodiment of the present disclosure, the attachment portion of the side handle may be provided behind the head housing. According to this configuration, there is no need to provide an attachment portion for the side handle on the housing portion, and further compactification of the housing portion can be achieved. Also, since the side handle is located closer to the rear than the housing portion, the restrictions on work due to the position of the side handle are alleviated, and the workability in a narrow space is also improved.

Example

[0011] Hereinafter, examples of the present disclosure will be described based on the drawings. FIG. 1 is a perspective view showing a grinder as an example of a power tool. FIG. 2 is a plan view of the grinder. FIG. 3 is an enlarged cross-sectional view of the portion taken along line A - A in FIG. 2. The grinder 1 includes an outer housing 2 and an inner housing 3 as a main body housing 1a. The outer housing 2 and the inner housing 3 are made of resin. A metal gear housing 4 is connected to the front side of the main body housing 1a. The gear housing 4 is an example of the head housing of the present disclosure. A bearing retainer 5 is assembled to the lower part of the gear housing 4, and a spindle 6 projects downward from the bearing retainer 5. The outer housing 2 has a cylindrical shape extending in the front-to-back direction, and a narrow-diameter grip portion 7 is formed at the rear. A switch lever 8 is provided on the grip portion 7. A power cord 9 is connected to the rear end of the grip portion 7. Multiple air intake ports 10, 10... are formed on the left and right sides of the wide-diameter portion of the outer housing 2. Handle mounting portions 11, 11 are provided on the left and right sides of the front end of the outer housing 2. The handle mounting portions 11 are plate-shaped, extending outward from the front end of the outer housing 2 to the left and right, and then projecting forward. Screw holes 12 (Figures 2 and 6) are formed in the handle mounting portions 11, into which the side handle 13 is screwed in.

[0012] The inner housing 3 houses the motor 15. The motor 15 is held with its output shaft 16 facing forward and backward. A cylindrical rubber 17 is fitted around the outer circumference of the inner housing 3. The outer housing 2 holds the inner housing 3 via the cylindrical rubber 17. The cylindrical rubber 17 is fitted with a metal fixing ring 18 to which handle mounting portions 11, 11 are screwed. A partition plate 19 is provided between the inner housing 3 and the gear housing 4. The output shaft 16 protrudes into the gear housing 4 through the partition plate 19. A bearing 20 supporting the output shaft 16 is provided on the partition plate 19. A fan 21 is provided on the output shaft 16 behind the partition plate 19.

[0013] The gear housing 4 integrates a connecting portion 25 and a gear housing portion 26. The connecting portion 25 has a rectangular shape when viewed from the front, and each corner is screwed to the inner housing 3 from the front by four screws 22, 22... together with a partition plate 19. The gear housing 26 protrudes forward from the center of the connecting portion 25 in both the vertical and horizontal directions. The gear housing 26 has a rectangular shape in plan view with an opening at the bottom. The width of the gear housing 26 is smaller than the width of the connecting portion 25. As shown in Figure 4, multiple arc-shaped lateral exhaust ports 27, 27... are formed symmetrically on both sides of the gear housing 26 on the front of the connecting portion 25. Multiple oval-shaped upper exhaust ports 28, 28 are formed above the gear housing 26 on the front of the connecting portion 25, extending in the left-right direction. Multiple arc-shaped lower exhaust ports 29, 29 are formed below the gear housing 26 on the front of the connecting portion 25. In other words, each exhaust port 27, 28, 29 is arranged to surround the base of the gear housing 26 when viewed from the front.

[0014] The output shaft 16 passes through the connecting portion 25 and protrudes into the gear housing portion 26. A first bevel gear 30 is fixed to the tip of the output shaft 16 within the gear housing portion 26. The bearing retainer 5 is cylindrical in shape, with its upper end having the same shape as the gear housing 26 when viewed from above, and is screwed to the lower part of the gear housing 26 from below. The gear housing 26 is covered from above by a front cover 31. The front cover 31 is made of resin and covers the top surface of the gear housing 26, as well as the front and left and right sides of the gear housing 26, and is sandwiched and fixed between the gear housing 26 and the bearing retainer 5. Here, as shown in Figure 3, the vertical distance D1 from the axis A1 of the output shaft 16 to the upper end of the gear housing 26 including the front cover 31 is less than half the vertical distance D2 from the axis A1 to the upper end of the connecting portion 25. Therefore, the gear housing 26 including the front cover 31 is smaller than the connecting portion 25 in both the vertical and horizontal directions.

[0015] The spindle 6 is positioned vertically, straddling the gear housing 26 and the bearing retainer 5. The upper end of the spindle 6 is supported by a bearing 32 held in the gear housing 26. The middle portion of the spindle 6 is supported by a bearing 33 held in the bearing retainer 5. A second bevel gear 34 is fixed to the spindle 6 above the bearing 33. The second bevel gear 34 meshes with the first bevel gear 30. The upper surface of the second bevel gear 34, excluding the teeth on its outer circumference, is a conical surface 35 that gradually rises towards the center. As shown in Figures 5 and 6, three recesses 36, 36·· are formed on this conical surface 35. Each recess 36 extends radially outward from the spindle 6. Each recess 36 is arranged at equal intervals in the circumferential direction of the second bevel gear 34. The lower end of the spindle 6 protrudes downward through the bearing retainer 5. A threaded portion 37 is provided at the lower end of the spindle 6. An inner flange 38 is fitted to the upper side of the threaded portion 37. Below the inner flange 38, an outer flange 39 is screwed onto the threaded portion 37. The tool tip 40 is fixed to the spindle 6 by sandwiching the tool tip (e.g., a disc-shaped grinding wheel) 40 between the inner flange 38 and the outer flange 39 and tightening the outer flange 39. A wheel cover 41 is attached to the bearing retainer 5, covering the upper rear surface and circumferential surface of the tool tip 40.

[0016] The gear housing 26 and the front cover 31 are provided with a locking mechanism 45 that allows the rotation of the spindle 6 to be arbitrarily restricted. The locking mechanism 45 comprises a locking member 46, a coil spring 47, and an operating button 48. The locking member 46 comprises two engaging pins 49, 49 and a connecting portion 50. The engaging pins 49, 49 are shafts that extend vertically and are arranged symmetrically on the left and right sides of the axis A2 of the spindle 6 when viewed from the front. The connecting portion 50 is a rod that extends horizontally, and the upper ends of the engaging pins 49 are press-fitted to both its left and right ends. Therefore, the locking member 46 has an inverted U-shape when viewed from the front. A support base 51 is formed protruding from the upper surface of the gear housing 26, behind the axis A2 of the spindle 6. The support base 51 has a rectangular shape in plan view, with its upper surface defined in the front-rear and left-right directions, and extending left-right across the bearing 32. A pair of through holes 52, 52 are formed through the support base 51 in the vertical direction. The lower part of each through hole 52 is a larger diameter hole 53 than the upper part, opening into the interior of the gear housing 26. A pair of left and right support plates 54, 54 are provided behind the support base 51. Each support plate 54 is erected along the front-to-back direction on the upper surface of the gear housing 26 and extends upward. A semicircular notch 55 is formed at the upper end of each support plate 54.

[0017] The left and right engagement pins 49, 49 protrude into the gear housing 26 through the through holes 52, 52. In a plan view, the engagement pins 49, 49 are located concentrically with the radially outer ends of the recesses 36, 36·· of the second bevel gear 34. The lower end of each engagement pin 49 is cut at an angle to match the shape of the conical surface 35 of the second bevel gear 34. An O-ring 56 located in the large diameter hole 53 is externally mounted on the lower part of each engagement pin 49. At the center in the left-right direction between the lower surface of the joint 50 and the upper surface of the support base 51, two bottomed holes 57, 57 are formed, with their openings facing each other in the vertical direction. The coil spring 47 is supported in the vertical direction by inserting its ends into the upper and lower bottomed holes 57, 57, respectively, and biases the locking member 46 upward. At the rear of the front cover 31, in the center in the left-right direction, a frame portion 60 is formed that bulges upward. The frame portion 60 has a rectangular shape in plan view that extends in the left-right direction, and a space is formed between the support base 51 and the frame portion 60 that allows the connecting portion 50 to move up and down. An operating window 61 is formed in the frame portion 60 that opens up the space except on the left, right, and rear sides.

[0018] The operation button 48 is located on the lower side of the frame 60. The operation button 48 has a front button portion 62 and a rear support portion 63 integrated into one unit. The button portion 62 is rectangular in plan view and fits within the operating window 61 of the frame portion 60, with its front portion curving downwards as it moves forward. A pressing portion 64 extending in the left-right direction is provided protruding downwards from the lower surface of the button portion 62. The support portion 63 is connected to the rear end of the button portion 62, extends downward, and then bends backward, forming an L-shape in side view. A pivot rod 65 extending in the left-right direction is integrally formed at the rear end of the support portion 63. The operation button 48 is assembled by first assembling the locking member 46 together with the coil spring 47 into the gear housing 26, and then placing the pivot rod 65 of the support part 63 onto the notches 55, 55 of the receiving plates 54, 54 of the gear housing 26. When the front cover 31 is placed over it in this state, the pivot rod 65 is sandwiched between the receiving plates 54, 54 and the front cover 31, as shown in Figure 3. Thus, the operation button 48 is supported so that it can swing up and down around the pivot rod 65.

[0019] However, the pressing portion 64 of the button portion 62 is in contact from below by the connecting portion 50 of the locking member 46, which is biased upward by the coil spring 47. Therefore, under normal conditions, the operating button 48 is biased to the upward swing position shown in Figure 3, where the support portion 63 contacts the frame portion 60 at the rear of the operating window 61. In this upward swing position, the button portion 62 is located on the upper side inside the operating window 61. At this time, as shown in Figure 5, the locking member 46 is in its upper limit position, where the O-rings 56, 56 of the engaging pins 49, 49 are located at the upper ends of the large diameter holes 53, 53 of the through holes 52, 52. At this upper limit position, the lower ends of the engaging pins 49, 49 are located above the recess 36 of the second bevel gear 34 and do not engage with the recess 36 in the rotational direction (non-engaged position). On one hand, the button portion 62 of the operation button 48 is pushed downward from the upper swing position. Then, as shown in FIG. 7, the operation button 48 swings downward about the fulcrum rod 65, and the front end of the button portion 62 comes into contact with the upper surface of the front cover 31 to reach the lower swing position. Thus, the coupling portion 50 is also pressed downward by the pressing portion 64, and the locking member 46 moves to the lower limit position against the biasing force of the coil spring 47. At this lower limit position, as shown in FIG. 8, the engaging pins 49, 49 enter into the two recesses 36, 36 of the second bevel gear 34 at their lower ends and can engage with the recess 36 in the rotational direction (engaging position).

[0020] The grinder 1 configured as described above is operated by pushing the switch lever 8 to turn on a switch (not shown) inside the grip portion 7. Then, the motor 15 is driven and the output shaft 16 rotates. The rotation of the output shaft 16 is transmitted from the first bevel gear 30 to the second bevel gear 34 and then transmitted to the spindle 6. Thus, the tip tool 40 rotates and grinding of the workpiece becomes possible. At this time, in the gear housing 4, the locking mechanism 45 is disposed between the axis A2 of the spindle 6 and the connecting portion 25, and due to the setting of D1 < D2 / 2 described above, the height of the gear accommodating portion 26 is kept low. Therefore, it is less likely that the gear accommodating portion 26 and the front cover 31 block the operator's view. Also, it becomes easier to work in a narrow space.

[0021] Then, the fan 21 rotates along with the rotation of the output shaft 16. Then, outside air is sucked in from the rear intake ports 10, 10 ···. This air flows forward inside the inner housing 3, passes through the motor 15, and then passes through a plurality of through holes 19a, 19a ··· (FIG. 6) provided in the partition plate 19 from the outer periphery of the fan 21, and is discharged forward through the exhaust ports 27, 28, 29 of the connecting portion 25. The motor 15 is cooled by this cooling air. Here, since the opening area is widely ensured by the exhaust ports 27, 28, 29 provided in the connecting portion 25, the amount of air flowing inside the inner housing 3 increases, and the motor 15 is effectively cooled.

[0022] When removing the tip tool 40 for replacement or other purposes after the work is completed, the locking mechanism 45 presses the button portion 62 of the operating button 48 downward. As described above, the operating button 48 swings around the pivot rod 65 to the downward swinging position shown in Figures 7 and 8, and the locking member 46 moves to the lower limit position against the biasing force of the coil spring 47. At this time, since the button portion 62 swings at a position away from the pivot rod 65, it can be pressed with a small force against the biasing force of the coil spring 47. In addition, since the pressing force on the button portion 62 acts evenly on the symmetrical engagement pins 49, 49 via the coupling portion 50, the engagement pins 49, 49 descend smoothly without tilting.

[0023] When the locking member 46 reaches its lower limit position, the lower ends of the engaging pins 49, 49 simultaneously engage with the two recesses 36, 36 of the second bevel gear 34. As a result, the rotation of the second bevel gear 34 is restricted by the locking member 46. In this state, the outer flange 39 can be loosened using a tool, allowing for replacement of the tip tool 40, etc. In this case, the locking member 46 has two engaging pins 49, 49 that engage with two recesses 36, 36, so when the outer flange 39 is loosened or tightened, the stress generated in the locking member 46 is distributed. In particular, since the engaging pins 49, 49 are arranged symmetrically, the stress is distributed uniformly. Therefore, the strength and durability of the locking mechanism 45 are improved. In addition, the rotation of the spindle 6 can be reliably locked. Furthermore, even though two engagement pins 49, 49 are provided, there is only one operating button 48, so operability is not impaired.

[0024] When the locking member 46 descends, the lower ends of the engaging pins 49, 49 may not align with the recesses 36, 36 and may come into contact with the conical surface 35 of the second bevel gear 34. In this case, the lower ends of the engaging pins 49, 49 can be aligned by rotating the tip tool 40 to rotate the second bevel gear 34 and changing the position of the recesses 36, 36. When the tip tool 40 is replaced and the pressure on the button 62 is released, the locking member 46 returns to the upper limit position shown in Figures 3 and 5 due to the biasing force of the coil spring 47, separating the engagement pins 49, 49 from the recesses 36, 36. At the same time, the operating button 48 is also pressed from below by the coupling part 50 and returns to the upward swing position.

[0025] As described above, the grinder 1 comprises a main body housing 1a housing a motor 15 and a fan 21 for cooling the motor 15, a gear housing 4 connected to the front side of the main body housing 1a, a spindle 6 housed in the gear housing 4 and on which a cutting tool 40 can be attached and detached, and a locking mechanism 45 housed in the gear housing 4 and capable of locking the rotation of the spindle 6 at will. The gear housing 4 is formed from a gear housing portion 26 (an example of a housing portion) that houses the spindle 6 and the locking mechanism 45, and a connecting portion 25 connected to the main body housing 1a. Furthermore, the grinder 1 has a locking mechanism 45 positioned in the central region of the gear housing 4 in the left-right direction, making the left-right width of the gear housing 26 smaller than the left-right width of the connecting portion 25, and horizontal exhaust ports 27 (an example of exhaust ports) are formed on both the left and right sides of the gear housing 26 in front of the connecting portion 25 to discharge the cooling air from the motor 15 generated by the rotation of the fan 21. With this configuration, even if the gear housing 4 is equipped with a locking mechanism 45 for the spindle 6, a wide opening area for the lateral exhaust port 27 can be secured, resulting in high cooling efficiency. In addition, the gear housing 26 is compact, making grinding work possible even in relatively narrow spaces, and improving visibility during operation.

[0026] The lateral exhaust ports 27, 27 are formed on both the left and right sides of the gear housing 26. Therefore, by arranging the lateral exhaust ports 27 in a balanced manner, a wide opening area can be secured, thereby improving cooling efficiency. The upper exhaust port 28 and the lower exhaust port 29 are formed on both the upper and lower sides of the gear housing portion 26 on the front surface of the connecting portion 25. Therefore, a wider opening area can be secured in combination with the side exhaust port 27. The spindle 6 is positioned with its axis A2 oriented vertically, and the locking mechanism 45 is positioned between the axis A2 of the spindle 6 and the connecting portion 25. Therefore, even if the locking mechanism 45 is located in the center in the left-right direction, the height of the upper end of the gear housing 26 can be kept low, which helps to ensure visibility during operation. The motor 15 is positioned with its output shaft 16 facing forward and backward, and the vertical distance D1 from the axis A1 of the output shaft 16 to the upper end of the gear housing 26 is less than half the vertical distance D2 from the axis A1 of the output shaft 16 to the upper end of the connecting portion 25. Therefore, the upper height of the gear housing 26 can be kept lower, and further improvement in visibility can be expected.

[0027] The gear housing 26 and the connecting portion 25 are integrally formed from a single component. Therefore, the structure is simplified and the number of parts is reduced. The gear housing 26 is made of metal, and its surface is covered with a front cover 31 (an example made of resin). Therefore, while ensuring the rigidity of the gear housing 26, the operator's hands will no longer come into direct contact with the gear housing 26. As a result, the user experience when operating the locking mechanism 45 will be improved. The screw holes 12 (an example of a mounting part) for attaching the side handle 13 are located behind the gear housing 4. Therefore, it becomes unnecessary to provide screw holes in the gear housing 26, making the gear housing 26 even more compact. In addition, since the side handle 13 is located further rearward than the gear housing 26, the constraints on work due to the position of the side handle 13 are reduced, improving workability in confined spaces.

[0028] The following are examples of changes to this disclosure. The housing is not limited to a structure that is positioned in the center of the connecting section in the vertical, horizontal, or lateral directions, as in the gear housing in the example above. It is sufficient if an exhaust port can be formed on at least one side of the front of the connecting section, even if it is slightly offset to the left or right or vertically, rather than being precisely in the center. The shape of the housing itself is also not limited to the example above; it may be semi-elliptical or semi-oblong in plan view, or semi-circular in front view, etc. The number and shape of each exhaust port in the connecting section are not limited to the examples above. For example, all exhaust ports may be arc-shaped or oval-shaped, round holes or square holes may be used, or a combination of these may be used. Depending on the position and shape of the housing, the lateral exhaust port does not have to be symmetrical as in the example above. The lateral exhaust port may be provided on only one side of the housing, either the left or the right. Either the upper exhaust port or the lower exhaust port, or both, can be omitted.

[0029] The distance from the axis of the output shaft to the upper end of the housing may be half the distance from the axis to the upper end of the connecting part. However, this distance setting is not required if visibility can be ensured. The position of the locking mechanism is not limited to between the spindle axis and the connecting part. If an exhaust port can be formed on either the left or right side, the locking mechanism may be positioned, for example, on the left or right outer side or in front of the spindle axis. The head housing is not limited to a structure in which the connecting portion and the gear housing portion are formed integrally, as in the gear housing example above. The connecting portion and the gear housing portion may be formed separately and then joined together. The resin covering the housing is not limited to a cover structure like the front cover in the example above. The resin may be integrally provided on the surface of the housing by, for example, insert molding. The resin can also be omitted. The mounting points for the side handles do not have to be screw holes. If the storage compartment can be made more compact, the mounting points can also be located on the sides of the compartment.

[0030] The locking mechanism is not limited to the structure shown in the example above. For example, the number of engaging pins in the locking member is not limited to two; three or more can be provided. The engagement pins do not necessarily have to be provided in separate left and right regions of the head housing. The coupling portion may be extended upwards from its center and pressed by the operating portion. The engaging pin may be a rod shorter in length than the example above, and its cross-section may not be circular. Depending on the outer shape of the gear, the lower end of the engaging pin may not be a sloped surface. The engaging pin may also be formed integrally with the coupling part rather than being separate. Multiple coil springs may be used. Other elastic materials may also be used. The structure of the operating button is not limited to the example above. For example, the operating button may have a circular shape in plan view, or the pivot rod may be located on the front or left / right side. The operating button may have a structure that moves up and down rather than swinging around the pivot rod. The operating button may be omitted, and the operating part may be integrally formed on the upper surface of the locking member so that it can be operated directly. The locking mechanism is not limited to the structure of the example above, but may also be a conventional structure in which one engagement pin biases the bevel gear and locks the rotation of the spindle by engaging with the bevel gear.

[0031] In addition, the grinder may be a DC tool that uses a battery pack, rather than an AC tool that uses commercial power. The main housing of the grinder is not limited to the structure consisting of an outer housing and an inner housing as in the example above. For example, it may have only an outer housing as the main housing. The power tools described herein are not limited to grinders. For example, the head housing structure described herein is applicable to other grinding and polishing tools such as polishers and sanders. [Explanation of symbols]

[0032] 1. Grinder, 2. Outer housing, 3. Inner housing, 4. Gear housing, 5. Bearing retainer, 6. Spindle, 10. Intake port, 11. Handle mounting section, 12. Screw hole, 13. Side handle, 15. Motor, 16. Output shaft, 21. Fan, 25. Connecting section, 26. Gear housing, 27. Side exhaust port, 28. Upper exhaust port, 29. Lower exhaust port, 30. First bevel gear, 31. F Front cover, 34...Second bevel gear, 36...Recess, 37...Threaded section, 38...Inner flange, 39...Outer flange, 40...Tip tool, 45...Locking mechanism, 46...Locking member, 47...Coil spring, 48...Operation button, A1...Axis of the output shaft, A2...Axis of the spindle, D1...Vertical distance from the axis of the output shaft to the upper end of the front cover, D2...Vertical distance from the axis of the output shaft to the upper end of the connecting section.

Claims

1. A main body housing that extends in the front-to-back direction and houses a motor positioned with its output shaft facing forward and a fan for cooling the motor, The head housing is connected to the front side of the main body housing, A spindle housed in the head housing and positioned with its axis oriented vertically, from which a cutting tool can be attached and detached, The head housing includes a locking mechanism that can arbitrarily lock the rotation of the spindle, The head housing is formed from a housing portion that accommodates the spindle and the locking mechanism, and a connecting portion that connects to the main body housing, The locking mechanism is positioned between the axis of the spindle and the connecting portion and in the central region of the head housing in the left-right direction, and the left-right width of the housing portion is formed to be smaller than the left-right width of the connecting portion, and an exhaust port is formed on at least one side of the housing portion on the front of the connecting portion to discharge the cooling air of the motor generated by the rotation of the fan.

2. The power tool according to claim 1, characterized in that the exhaust ports are formed on both the left and right sides of the housing.

3. The power tool according to claim 1 or 2, characterized in that the exhaust port is also formed on at least one of the upper and lower sides of the housing portion on the front surface of the connecting portion.

4. The power tool according to any one of claims 1 to 3, characterized in that the vertical distance from the axis of the output shaft to the upper end of the housing is less than or equal to half the vertical distance from the axis of the output shaft to the upper end of the connecting portion.

5. The power tool according to any one of claims 1 to 4, characterized in that the housing portion and the connecting portion are integrally formed in a single member.

6. The power tool according to any one of claims 1 to 5, characterized in that the housing is made of metal and its surface is covered with resin.

7. The power tool according to any one of claims 1 to 6, characterized in that the mounting portion for the side handle is provided behind the head housing.

Images