JP2005193310A - Electric hammer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric hammer effective for improving cooling efficiency further. <P>SOLUTION: The electric hammer has a driving motor 121, a tip tool 111 for performing prescribed machining of a workpiece, a first housing 105, which houses a driving part for applying striking to the tip tool by its linear motion via the driving motor and the driving motor, and a second housing 107 which is connected to the first housing and houses the driving part. The electric motor has the following constitution. Cooling air used for cooling the driving motor is discharged from the first housing to atmosphere. After that, the cooling air is circulated into a ventilation passage 139 set inside the second housing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cooling technique for an electric hammer capable of performing a hammering operation on a workpiece by causing a tip tool to perform a striking motion.

  As an example of the electric hammer, Japanese Patent Laid-Open No. 2000-84868 (Patent Document 1) discloses a technique for cooling a drive motor and a drive unit. In this conventional electric hammer, a first cooling air passage for cooling a drive motor and a second cooling air passage for cooling a driving unit such as a striking mechanism and a power transmission mechanism are partitioned in a housing. It is set. Then, by rotating the cooling fan, external air is introduced into the cooling air passage from the suction port provided for each cooling air passage to individually cool the drive motor and the drive unit, and then the cooling air is joined to the housing. It is configured to discharge to the outside.

The above disclosed technique is configured to cool by introducing air into the housing. As for the cooling air passage for the drive motor, since there is a gap between the rotor and the stator, an air flow path can be formed by the gap, so that a relatively smooth air flow with low flow resistance can be obtained. It is possible to secure. However, if the cooling passages of the drive motor and the drive unit are made a series of passages, the total length of the passages becomes long and the resistance of the air flow becomes large. Further, regarding the cooling air passage for the drive unit, the shape of the passage formed in the housing tends to be intricate due to the large number of components of the drive unit and the complicated structure. Furthermore, the passage cannot be formed linearly because the drive unit and the motor are arranged orthogonally or arranged in two upper and lower stages. As a result, there is a problem in that the flow resistance of the cooling air increases, adversely affects the suction function of the cooling fan, and the cooling efficiency decreases.
JP 2000-84868 A

  This invention is made | formed in view of this point, and it aims at providing an effective technique in raising cooling efficiency more in an electric hammer.

In order to achieve the above object, the invention described in each of the claims is configured.
According to the first aspect of the present invention, a drive motor, a tip tool that performs a predetermined machining operation on the workpiece, a drive unit that linearly moves via the drive motor and strikes the tip tool, and a drive An electric hammer having a first housing that houses a motor and a second housing that is connected to the first housing and houses a drive unit is configured. The “electric hammer” according to the present invention is not limited to a mode in which the cutting tool performs a crushing operation or a drilling operation by causing the cutting tool to perform a long-axis hitting operation. It also includes a mode that can be used in a so-called hammer drill mode, in which a crushing operation, a drilling operation, or the like is performed on a workpiece by performing an operation and a rotation operation. The “drive unit” typically includes a piston that linearly moves in a cylinder via a motion conversion mechanism that converts rotation of the drive motor into linear motion, and an air spring that is generated in the cylinder based on the linear motion of the piston. It is composed of an impactor that linearly moves at high speed by the action, and an intermediate element that linearly moves by collision of the impactor and strikes the tip tool, but the impactor directly strikes the tip tool without going through the intermediate element. Include. In addition to the above, the “drive unit” is a cylinder that linearly moves via a motion conversion mechanism that converts rotation of the drive motor into linear motion, and an air spring that is generated in the cylinder based on the linear motion of the cylinder. Based on an impactor that linearly moves at a high speed based on this, an intermediate element that linearly moves by the impact of the impactor, and that strikes the tip tool, or via a motion conversion mechanism that converts rotation of the drive motor into linear motion Consists of a piston that moves linearly in the cylinder, the cylinder that moves linearly via an air spring generated in the cylinder by the linear movement of the piston, and a striker that linearly moves when the cylinder collides and hits the tip tool. Any of the embodiments to be included is suitably included. Furthermore, a form using a mechanical spring instead of an air spring in the above-described components may be used.

  According to the first aspect of the present invention, as a characteristic configuration, after the cooling air used for cooling the drive motor is discharged from the first housing to the atmosphere, the ventilation passage is set in the second housing. It has a configuration for distribution. In addition, as an aspect of the “second housing” in the present invention, an aspect in which the second housing is formed only by a housing main body that accommodates the driving portion, or a housing main body that accommodates the driving portion, and an outer side of the housing main body. Any of the aspects established from the attachments to be attached is suitably included. And as a mode of “setting a ventilation passage in the second housing” in the present invention, a mode in which the ventilation passage is formed in the housing main body as long as the second housing is formed only by the housing main body. Corresponds to this. Further, if the second housing is an aspect formed by the housing main body and an accessory on the outside of the housing main body, an air passage is formed in the housing main body or formed between the housing main body and the accessory. Any of the aspects, and also the aspects formed respectively in the housing main body and between the housing main body and the attached object, can be suitably handled. Further, as an aspect in which the ventilation passage is formed in the housing body, when the driving unit accommodated in the housing body has a cylinder, an aspect in which the ventilation passage is formed between the cylinder and the housing body is preferable. .

  In the present invention, cooling air is circulated in the first housing to cool the drive motor and then discharged to the atmosphere. In the case of a drive motor, the gap between the rotor and the stator or between the stator and the inner surface of the housing can be set as an air passage having a low flow resistance. Performance can be ensured. A cooling fan is typically used as a means for circulating the cooling air. In the present invention, a ventilation passage is set in the second housing that houses the drive unit, and the cooling air discharged from the first housing into the atmosphere is taken into the ventilation passage and circulated. The second housing can be cooled without impairing the fan suction function. In the second housing, heat is generated by the compression action of the air by the piston or by the striking operation of the tip tool by the striking element, and the second housing is heated to a high temperature. It can be cooled efficiently. In addition, this invention does not prevent installation of the wind guidance means which guides the cooling air discharged | emitted from the 1st housing to the channel | path for ventilation.

(Invention of Claim 2)
According to a second aspect of the present invention, in the electric hammer according to the first aspect, the first housing and the second housing are connected in a crossing manner, and the crossing connection portion is connected to the first hammer. An exhaust port for discharging the cooling air from the housing and an inlet for passing the cooling air discharged from the exhaust port into the air passage are set. In the case of a so-called angle-shaped electric hammer in which the first housing and the second housing are arranged in an intersecting manner, for example, in an intersecting manner at an angle of approximately 90 degrees, a cooling is provided at a portion where the two housings intersect and connect. Since the air exhaust port and the inlet can be set close to each other, the cooling air discharged from the first housing can be easily taken into the air passage without needing to set the cooling air guiding means. be able to. This provides a reasonable cooling structure. In addition, when setting an exhaust port and an inlet in an intersection connection part, the aspect which sets an inlet in the position which can take in the cooling air discharged | emitted from the said exhaust port with respect to an exhaust port is suitable.

(Invention of Claim 3)
According to the third aspect of the present invention, the second housing in the electric hammer according to the first or second aspect includes a housing main body that houses the drive unit and a detachable cover member that covers the housing main body. And a ventilation passage is set between the housing body and the cover member. The housing main body of the second housing in the electric hammer is generally called a barrel portion and is generally formed in a cylindrical shape (barrel shape). Depending on the work form, the worker may hold the original hand grip portion with one hand and may perform the processing work by holding the barrel portion with the other hand. Therefore, when the housing body is covered with a detachable cover member, there is an effect that the operator's hand is not heated even if the cover member is gripped in order to perform the above-described work mode. For this reason, the cover member is preferably made of a material having low thermal conductivity, such as rubber or resin. Further, as an aspect of “detachable cover member” with respect to the housing body, the cover member is set to a shape (cylindrical shape) having a slit similar to the outer shape of the second housing and extending in the axial direction. A mode in which the slit is expanded and removed is suitable. For example, the cover member is constituted by a plurality of members divided in the circumferential direction, and the plurality of members are individually fixed to the outer peripheral surface of the housing body or connected to each other. A mode in which it is fastened to is included.
In the invention according to claim 3, a ventilation passage is set between the housing body and the cover member. The ventilation passage set in this way can be formed so as to reduce the flow resistance without being subjected to special restrictions, and the cover member can be cooled by the cooling air flowing through the ventilation passage. When the cover member is used as a hand grip portion, it is more effective.

  According to the present invention, in the electric hammer, a technique effective in increasing the cooling efficiency is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 shows the overall configuration of the electric hammer, FIG. 2 shows the external configuration of the electric hammer on the tip side, and FIG. 3 shows the overall configuration of the barrel cover in plan view. . 4 to 6 show the cross-sectional structures of the portions cut based on the respective cross-section indicating lines in FIG. In addition, the arrow in drawing shows the flow of the cooling air.

  As shown in FIG. 1, the electric hammer 101 according to the present embodiment is mainly configured by a main body portion 103 that forms an outline of the electric hammer 101 when viewed generally. The main body 103 mainly includes a motor housing 105, a barrel 107, and a tool holder 109 that occupies a tip (front end) region (left side in FIG. 1) of the barrel 107. The barrel 107 includes a barrel main body 107a formed in a substantially cylindrical shape and a barrel cover 131 that covers the barrel main body 107a. A handle (hand grip) 113 is provided on the rear end side (right side in FIG. 1) of the motor housing 105. The motor housing 105 corresponds to the “first housing” in the present invention, and the barrel 107 corresponds to the “second housing” in the present invention. The barrel main body 107a corresponds to the “housing main body” in the present invention, and the barrel cover 131 corresponds to the “cover member” in the present invention.

  Although not shown in the drawing except for a part for convenience, a hitting drive mechanism for applying a hitting operation to the hammer bit 111 held by the tool holder 109 is built in the main body 103. This hammer bit 111 corresponds to the “tip tool” in the present invention.

The configuration of the hammer drive mechanism of the hammer bit 111 is well known in the art and will be described only briefly. A drive motor 121 as a drive source is installed in the motor housing 105. The rotational output of the drive motor 121 is converted into a reciprocating linear motion of the piston through a crank mechanism installed in the motor housing 105. The striker as the striker linearly moves at high speed in the tip direction (forward) by the action of a so-called air spring generated in the cylinder based on the linear motion of the piston, and collides with the impact bolt as the intermediate. Along with this, the impact bolt further linearly moves in the tip direction at high speed and collides with the hammer bit 111 held by the tool holder 109. Accordingly, the hammer bit 111 linearly moves at a high speed in the long axis direction (forward). In this manner, the hammer bit 111 performs a hammering operation (hammer operation), and thus a hammering operation such as a chipping operation on a workpiece (concrete) not shown is performed.
Of the above-described striking drive mechanism, the piston, the cylinder, the striking element and the intermediate element are arranged in the barrel main body 107a, and these constitute the “driving part” in the present invention.

  The striker and the impact bolt constitute a striking mechanism for striking the hammer bit 111 and are disposed in the barrel body 107a. The striking mechanism and the hammer bit 111 are configured to move linearly on substantially the same straight line. The crank mechanism constitutes a motion conversion mechanism. The axial direction of the drive motor 121 and the linear motion direction of the striking mechanism are arranged so as to intersect substantially orthogonally. Accordingly, as shown in FIG. 1, the outer shape of the motor housing 105 and the barrel main body 107a is an L shape that intersects substantially orthogonally in a side view. In other words, the barrel main body 107a is connected to the upper front portion of the motor housing 105, thereby forming a so-called angle-shaped electric hammer.

  A cooling fan 125 is attached to the output shaft 123 of the drive motor 121 so as to rotate integrally with the output shaft 123. The cooling fan 125 is rotated by energization driving of the drive motor 121 and sucks external (atmospheric) air from a suction port (not shown) opened at a lower end portion (lower side in FIG. 1) of the motor housing 105. In FIG. 1, the suction direction of the suction cooling air is indicated by arrows. The energization driving or the stop of the drive motor 121 is performed by operating a trigger 115 disposed on the handle 113. The cooling fan 125 constitutes cooling air for cooling, that is, cooling air circulation means for circulating the cooling air in the motor housing 105.

  The cooling air sucked into the motor housing 105 flows through the motor housing 105 and cools the drive motor 121 (and electric parts such as a motor control controller). The flow of the cooling air at this time uses a gap existing between the stator and the rotor, which is a constituent member of the drive motor 121, as a main passage. In the present embodiment, a centrifugal fan is used as the cooling fan 125. Therefore, the cooling air after cooling the motor is guided in the circumferential direction through the baffle plate 129 as shown by an arrow in FIG. 1, and then passes through the exhaust port 127 formed in the front wall portion 105a of the motor housing 105. It is configured to be discharged to the outside (atmosphere). As shown in FIGS. 1 and 2, the front wall portion 105a of the motor housing 105 is formed in a substantially flat surface, and the exhaust port 127 is located at a position in the vicinity of the connection portion of the front wall portion 105a with the barrel body 107a. Is open. The exhaust port 127 is formed continuously or intermittently over substantially the entire width of the front surface region of the motor housing 105. That is, when the cooling air sucked into the motor housing 105 from the suction port is discharged from the exhaust port 127 in a state where the operator holds the handle 113, the exhaust port 127 is discharged obliquely upward and forward. Therefore, the cooling air supplied to the motor cooling is discharged forward as viewed from the worker, and is not blown to the worker.

  The barrel main body 107a is configured to be entirely covered with a detachable barrel cover 131. The barrel cover 131 is made of rubber or resin having low thermal conductivity and moderate flexibility. As shown in FIG. 3, the barrel cover 131 has a generally cylindrical shape and has a slit 133 extending over the entire length in the axial direction, and can be expanded outward (in the radial direction) from the slit 133. ing. Therefore, the flexibility of the barrel cover 131 is preferably set to have a degree of flexibility that allows the operator to easily perform the expanding operation. The barrel cover 131 is mounted so as to cover the barrel main body 107a from the outer peripheral side or from the front (front end side) with the slit 133 widened, and is fixed by a fixing piece 135 having a surface fastener 137 as a fixing means. It is set as the structure. The fastening piece 135 is extended in the circumferential direction with a predetermined width so as to overlap the outer peripheral surface of the other end from the one end with the slit 133 interposed therebetween, and a surface fastener 137 is provided on the surface overlapping each other. . The barrel body 107a is made of metal such as aluminum.

  The barrel cover 131 attached to the barrel main body 107a forms a plurality of ventilation holes 139 between the barrel cover 107a and the outer peripheral surface of the barrel main body 107a. This ventilation hole 139 corresponds to the “ventilation passage” in the present invention. A plurality of ribs 141 extending in the axial direction are formed on the inner peripheral surface of the barrel cover 131 at a predetermined interval in the circumferential direction. When the barrel cover 131 is attached to the barrel main body 107a, the rib 141 The tip surface (projecting end surface) is in close contact with the outer surface of the barrel body 107a. Thus, a recess extending in the axial direction is formed between the rib 141 and the rib 141, and the recess and the outer peripheral surface of the barrel constitute a ventilation hole 139 (see FIG. 4). The ventilation hole 139 has a plurality of inlets 143 for taking in cooling air on the rear end side, which is the connection part side (right side in FIG. 1) between the motor housing 105 and the barrel body 107a, and is on the front end side. A plurality of outlets 145 for discharging cooling air are provided on the drill bit 111 side (left side in FIG. 1). The plurality of ventilation holes 139 are configured to communicate with each other on the inlet side and the outlet side.

  As shown in FIGS. 1 and 5, the inlet 143 is opened in the lower wall portion 131 a of the barrel cover 131 to communicate the ventilation hole 139 with the atmosphere. That is, the plurality of inlets 143 are juxtaposed across the entire width of the rear end lower surface region of the barrel cover 131 and are approximately 90 degrees with respect to the direction of cooling air discharged from the exhaust port 127 of the motor housing 105. It opens with a crossing angle. As shown in FIG. 6, the plurality of outlets 145 are opened in the upper wall portion 131 b and the side wall portion 131 c on the front end side of the barrel cover 131 to communicate the ventilation holes 139 with the atmosphere.

  The electric hammer 101 according to the present embodiment is configured as described above. Next, the operation and usage method of the electric hammer 101 will be described. When the drive motor 121 is energized and driven by the pulling and drawing operation of the trigger 115, the rotation output of the drive motor 121 is converted into a linear motion of the piston through the crank mechanism, and in the cylinder by the linear motion of the piston. An air spring action is generated, and the hammer bit 111 is added as a striking operation to the hammer bit 111 via a striking mechanism constituted by a striker and an impact bolt, and the hammer work by the hammer bit 111 is performed on the workpiece.

  When the cooling fan 125 is rotated by energization driving of the drive motor 121, outside air is sucked into the motor housing 105 from the suction port as cooling air, as indicated by an arrow in FIG. The cooling air passes through the motor housing 105 and cools the drive motor 105, and is then discharged from the exhaust port 127 to the outside (atmosphere). Of the cooling air discharged from the exhaust port 127 of the motor housing 105, the cooling air blown slightly upward flows into the ventilation hole 139 from the inlet 143 that opens close to the exhaust port 127. The cooling air that has flowed into the ventilation hole 139 flows through the ventilation hole 139 to cool the outer surface of the barrel body 107a, and then is discharged from the outlet 145. Thereby, the heat generated by the compression action of the air by the piston and the striking operation by the striking mechanism is rationally dissipated.

  As described above, in the present embodiment, after the cooling air used for cooling the drive motor 121 accommodated in the motor housing 105 is once discharged out of the motor housing 105, a part of the discharged cooling air is discharged. The outer surface of the barrel body 107a is cooled by being taken in and circulated through a ventilation hole 139 formed between the outer surface of the barrel body 107a and the barrel cover 131. In the conventional apparatus in which the cooling air is sucked into the motor housing 105 and the barrel 107 to cool the driving motor and the driving unit, various components in which the cooling air flowing in the barrel 107 is arranged in the barrel 107. As a result, the flow is obstructed, and the passage structure must have a large flow resistance. As a result, the suction function of the cooling fan 125 is degraded. However, when the cooling air is once discharged from the motor housing 105 as in the present embodiment, the cooling of the drive motor 121 can be efficiently cooled without impairing the suction function of the cooling fan 125. Can do.

  In addition, according to the present embodiment, since the ventilation hole 139 is formed between the outer surface of the barrel main body 107a and the barrel cover 113 that covers the barrel main body 107a, the flow can be performed without any special restriction. Since the ventilation hole 139 with low resistance can be formed, the barrel main body 107a can be efficiently cooled. The inlet 143 of the ventilation hole 139 is configured to open to the atmosphere. For this reason, when the cooling air after cooling the motor flows into the inlet 143, air in the atmosphere is also mixed. As a result, the temperature of the cooling air passing through the ventilation hole 139 is lowered than the temperature of the cooling air discharged from the motor housing 105, and as a result, the cooling effect of the barrel body 107a is further enhanced.

  Further, in the present embodiment, the exhaust port 127 of the motor housing 105 and the inlet 143 of the ventilation hole 139 on the barrel side are arranged close to the connection portion where the motor housing 105 and the barrel main body 107a intersect each other in a substantially orthogonal shape. Accordingly, it is possible to allow the cooling air discharged from the exhaust port 127 to flow into the atmosphere 143 to the inlet 143 of the air hole 139 without using any special guiding means, and rational intake of the cooling air is achieved. .

  By the way, at the time of hammer work, the worker may perform the hammer work by grasping the barrel main body 107a with the other hand in addition to grasping the original handle 113 with one hand. In the present embodiment, since the barrel main body 107a is almost entirely covered with the barrel cover 131, when the operator grips the barrel cover 131 to perform the hammering operation in the above-described form, the operator's hand is not heated. There is. In that sense, the barrel cover 131 is preferably made of a heat insulating material. The ventilation hole 139 also effectively acts as a heat insulating layer that blocks heat conduction from the barrel body 107a to the barrel cover 131. The barrel cover 131 is configured to be detachable from the barrel main body 107a. For this reason, it can be removed when unnecessary.

  In the present embodiment, the ventilation hole 139 that forms the cooling air passage is formed between the barrel main body 107a and the barrel cover 131 that covers the barrel main body 107a, but may be formed in the barrel main body 107a. Good. In the present embodiment, the barrel cover 131 is formed of a flexible material. However, for example, if an integral hinge is set on the opposite side of the slit 133 and is configured to be rotatably connected, the barrel main body 107a. It can be made of a hard material without impairing the attachment / detachment function. Further, in the present embodiment, the exhaust port 127 set in the motor housing 105 is cooled so that the direction of the cooling air exhausted from the exhaust port 127 flows toward the lower surface of the barrel body 107a obliquely above. It is preferable to set the opening position in consideration of the arrangement relationship with the fan 125.

In the present embodiment, the L-shaped electric hammer in which the motor housing 105 and the barrel main body 107a are arranged in an intersecting manner has been described. However, an electric hammer of the type in which the motor housing 105 and the barrel main body 107a are arranged in a straight line is described. Applicable. In that case, it is preferable to install a guide means for guiding the cooling air discharged from the exhaust port 127 to the inlet 143 of the ventilation hole 139 or a guide means for guiding the intake of the cooling air on the inlet 143 side of the ventilation hole 137. Of course, the installation of the guide means does not prevent the L-shaped electric hammer 101 from being implemented.
Moreover, although this Embodiment demonstrated the hammer bit 111 as a tip tool by the electric hammer which reciprocates linearly, it is natural that it can apply to what is called a hammer drill which makes a tip tool perform a linear reciprocating motion and a rotational motion. .

It is a partial cutting side view showing the whole composition of an electric hammer. It is a top view which shows the external appearance structure at the front-end | tip part side of an electric hammer. It is a top view which shows the whole structure of a barrel cover. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is CC sectional view taken on the line in FIG.

Explanation of symbols

101 Electric Hammer 103 Main Body 105 Motor Housing (First Housing)
105a Front wall 107 barrel (second housing)
107a barrel body 109 tool holder 111 hammer bit 113 handle 115 trigger 121 drive motor 123 output shaft 125 cooling fan 127 exhaust port 129 baffle plate 131 barrel cover (cover member)
131a Lower wall part 131b Upper wall part 131c Side wall part 133 Slit 135 Fastening piece (fastening means)
137 Surface fastener 139 Ventilation hole 141 Rib 143 Inlet 145 Outlet

Claims (3)

A drive motor; a tip tool that performs a predetermined machining operation on the workpiece; a drive unit that linearly moves via the drive motor to strike the tip tool; and a first housing that houses the drive motor And an electric hammer having a second housing connected to the first housing and accommodating the drive unit,
An electric hammer characterized in that the cooling air used for cooling the drive motor is discharged from the first housing to the atmosphere and then circulated through a ventilation passage set in the second housing. . The electric hammer according to claim 1,
The first housing and the second housing are connected in an intersecting manner, an exhaust port for discharging cooling air from the first housing to the intersecting connected portion, and an exhaust port from which the cooling air is discharged An electric hammer characterized in that an inlet for taking cooling air into the ventilation passage is set. The electric hammer according to claim 1 or 2,
The second housing includes a housing main body that houses the drive unit and a detachable cover member that covers the housing main body, and the ventilation housing is provided between the housing main body portion and the cover member. An electric hammer characterized in that a passage is set.

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