JP2009208208A - Working tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique that contributes to improving an assembling property of a damping mechanism in a hammering tool. <P>SOLUTION: The hammering tool includes: a motor 111 for driving a tool bit 119; a tool body 103 in which the motor 111 is housed; a dynamic damper body part 151 for damping the tool body 103 during hammering work; and a compulsorily driving mechanism part 171 driven by the motor 111 during hammering work, for compulsorily driving this dynamic damper body part 151 by adding external force other than a vibration of the tool body 103 to the dynamic damper body part 151, wherein at least one of the dynamic damper body part 151 and the compulsorily driving mechanism part 171 is assembled into the tool body 103 in a previously combined state of at least one of a plurality of constituent members constituting the dynamic damper body part 151 and a plurality of constituent members constituting the compulsorily driving mechanism part 171, namely as assembly bodies A1 and A2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration control technique for an impact tool that drives a tool bit linearly, such as a hammer or a hammer drill.

Japanese Unexamined Patent Publication No. 2003-11073 (Patent Document 1) discloses a configuration of an electric hammer provided with a vibration damping mechanism. This conventional electric hammer is provided with a dynamic vibration absorber as means for suppressing vibration in the long axis direction of the hammer bit associated with the hammer work, thereby reducing the vibration of the hammer during the hammer work. The dynamic vibration absorber has a weight capable of linear motion in a state in which an urging force is applied by a coil spring, and the weight moves in the long axis direction of the tip tool so as to control the hammer during hammering. It is said.
In a conventional electric hammer, a weight and a coil spring are arranged in a space having an annular cross section between a cylinder and a barrel portion that accommodates the cylinder.

However, in the arrangement configuration as described above, when assembling the electric hammer, an operation of individually assembling the weight and the coil spring, which are the components of the dynamic vibration absorber, to the cylinder or the barrel portion is required. In other words, the conventional electric hammer still has room for improvement in terms of ease of assembly with respect to the vibration damping mechanism.
JP 2003-11073 A

  This invention is made | formed in view of this point, and it aims at providing the technique which contributes to the improvement of the assembly | attachment property of a damping mechanism in an impact tool.

  In order to achieve the above object, a preferred embodiment of a striking tool according to the present invention is a striking tool that performs a predetermined hammering operation on a workpiece by a striking operation in the long axis direction of a tool bit. It has a vibration absorber body and a forced drive mechanism. The motor drives the tool bit. The tool body houses a motor. The dynamic vibration absorber main body controls the tool main body during hammering. The forcible drive mechanism is driven by a motor during hammering, and forcibly drives the dynamic vibration absorber main body by applying an external force other than the vibration of the tool main body to the dynamic vibration absorber main body. The “predetermined hammering work” in the present invention is not limited to a hammering work in which the tool bit performs only a linear striking operation, but also an electric hammering work in which a linear striking operation and a circumferential rotation operation are performed. Included.

  In the present invention, in terms of forcibly driving the dynamic vibration absorber main body by applying an external force other than the vibration of the tool main body to the dynamic vibration absorber main body, when the impact tool is hand-held, the impact tool The vibration value that is theoretically estimated to occur at the time of work on the impact tool may actually be output as a lower vibration value due to the pressing action of the hand of the operator. . For this reason, by applying a constant external force other than the vibration of the tool main body to the dynamic vibration absorber main body, the dynamic vibration absorber is forcibly and constantly driven, so that the vibration generated in the tool main body is In a situation where the apparent vibration value of the tool body is low due to being received, that is, in a situation where the operator's hand has received a considerable amount of vibration generated in the tool body, it is highly compatible with the design vibration. A vibration damping function adapted to the vibration value is imparted to the dynamic vibration absorber so that the operator's hand does not need to receive the vibration of the tool body part unnecessarily.

  According to a preferred embodiment of the impact tool according to the present invention, at least one of the dynamic vibration absorber main body and the forced drive mechanism is configured with a plurality of components constituting the dynamic vibration absorber main body and the forced drive mechanism. A state in which at least one of the plurality of constituent members is combined in advance, that is, an assembly body is assembled to the tool body.

  Therefore, according to the present invention, at least one of the dynamic vibration absorber main body or the forced drive mechanism constituting the vibration damping mechanism can be handled as one component by forming an assembly body. For this reason, the assembly | attachment operation | work with respect to a tool main body can be performed easily, and assembly | attachment property improves. Further, since the assembly body can be removed as one part, the repairability is improved.

According to the further form of the impact tool which concerns on this invention, it further has the barrel part joined to a tool main body, and the cylinder accommodated in a barrel part. The dynamic vibration absorber main body includes a weight that can linearly move in the tool bit long axis direction and an elastic element that applies a biasing force in the tool bit long axis direction to the weight, and the weight and the elastic element are connected to the cylinder. An assembly body is obtained by being assembled to one of the barrel portions.
According to the present invention, the dynamic vibration absorber main body can be handled as a single part integrated with the cylinder or barrel by assembling it to the cylinder or barrel. For this reason, it is only necessary to perform the work of assembling the cylinder or barrel portion to the tool body.

  According to the further form of the impact tool according to the present invention, the forcible drive mechanism section includes a cam shaft that is rotationally driven by a motor, an eccentric cam that is integrally formed with or attached to the cam shaft, and at least the length of the cam shaft. A bearing that rotatably supports one end in the axial direction is combined with a bearing housing that houses the bearing. The forcible drive mechanism is further arranged in series in the tool bit long axis direction to forcibly drive the dynamic vibration absorber main body by linearly moving in the tool bit long axis direction based on the rotational movement of the eccentric cam. The pin closer to the eccentric cam is assembled to the bearing housing so as to intersect the axis of the cam shaft, thereby forming an assembly body.

  As described above, according to the present invention, by assembling the cam shaft with the eccentric cam integrally formed or fixed to the bearing housing as the main body through the bearing, and further mounting the pin closer to the eccentric cam. It is an assembly body. Therefore, the bearing housing can be easily fixed to the tool body in such a manner that the bearing housing is inserted and fixed in the axial direction of the cam shaft from the opening for mounting the forced drive mechanism formed in the tool body into the tool body. It can be assembled.

The two pins arranged in series in the tool bit major axis direction convert the rotational motion of the eccentric cam into a linear motion, and use the elastic element of the dynamic vibration absorber main body as the driving force in the tool bit major axis direction. It is provided as a member which transmits to a weight via. The pin closer to the eccentric cam is required to have a certain thickness for the reason of ensuring the stabilization of the operation.
By the way, a barrel part is attached by fitting to the outer side of the cylindrical part formed in the tool main-body part. Then, when adopting a configuration in which the pin far from the eccentric cam is attached to the cylindrical portion, for example, if the pin diameter is large, the cylindrical portion must be formed thick, resulting in a large cylindrical portion. Diameter. In the present invention, the power transmission pin is composed of two pins, and the pin closer to the eccentric cam is the target of assembly. For this reason, the pin far from the eccentric cam can be set as thin as possible within a range in which the strength is guaranteed. As a result, it is possible to reduce the diameter of the barrel portion for attaching the barrel portion, and thus to reduce the diameter of the barrel portion.

  According to the further form of the impact tool which concerns on this invention, it further has the drive mechanism which converts the rotational output of a motor into linear motion, and drives a tool bit, and the sealed accommodation space which accommodates a drive mechanism. In the bearing housing, in a state where the bearing housing is assembled to the tool main body portion, lubricating oil is supplied to the air release mechanism and the storage space for adjusting the pressure of the storage space by communicating the inside and the outside of the storage space. A fuel filler cap for closing the fuel filler to be supplied is assembled, whereby an assembly body of the forced drive mechanism is configured. The “air bleeding mechanism” in the present invention typically has an air passage that communicates the inside of the housing space of the drive mechanism with the outside, and a cylindrical shape that contains a filter that adsorbs lubricating oil in the air passage. It is composed mainly of members. For example, it is set as the structure assembled | attached by inserting in the axial direction of a cam shaft with respect to the opening provided in the bearing accommodating part of the bearing housing.

  Thus, according to the present invention, the assembly body can be further improved by assembling the air bleed mechanism and the oil filler cap with the bearing housing.

  According to the present invention, in the impact tool, a technique that contributes to an improvement in the assembling property of the vibration damping mechanism is provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. This embodiment will be described using an electric hammer as an example of an impact tool. FIG. 1 shows the overall configuration of the electric hammer 101, FIG. 2 shows an enlarged configuration of the main part of the electric hammer 101, and FIG. 3 shows a further enlarged portion of FIG. 4 shows a state in which a plurality of constituent members constituting a dynamic vibration absorber 151 as a vibration damping mechanism are assembled to the cylinder 141 to form a dynamic vibration absorber assembly A1, and FIG. 5 shows a dynamic vibration absorber. A state in which a plurality of constituent members of the vibration mechanism 171 that actively drives 151 is combined into a vibration assembly body A2 is shown. FIG. 6 shows details of the power transmission pin 174 that transmits the driving force of the vibration exciting mechanism 171 to the dynamic vibration absorber 151.

  As shown in FIG. 1, an electric electric hammer 101 according to the present embodiment generally includes a main body 103 that forms an outline of the electric hammer 101, and a tip region in the major axis direction of the main body 103. A tool holder 137 connected to (left side in the figure), a hammer bit 119 detachably attached to the tool holder 137, and an operator connected to the other end part (right side in the figure) in the major axis direction of the main body 103 are gripped. The hand grip 109 is mainly used. The main body 103 corresponds to the “tool main body” in the present invention, and the hammer bit 119 corresponds to the “tool bit” in the present invention. The hammer bit 119 is capable of relative reciprocation in the major axis direction (major axis direction of the main body 103) with respect to the tool holder 137, and relative rotation in the circumferential direction is restricted. Held in a state. For convenience of explanation, the hammer bit 119 side is referred to as the front, and the hand grip 109 side is referred to as the rear.

  The main body 103 is mainly composed of a motor housing 105 that accommodates the drive motor 111 and a gear housing 107 that is joined to the motor housing 105 and accommodates the motion conversion mechanism 113, and a striking element is disposed in front of the gear housing 107. A barrel portion 108 that accommodates 115 is disposed. The gear housing 107 is disposed on the front side and the upper region of the motor housing 105. The barrel portion 108 is joined to the front end portion of the gear housing 107 and extends forward on the long axis of the hammer bit 119. In addition, the hand grip 109 is formed in a U shape with an opening at the front, and is connected to the rear portion of the motor housing 105. In the upper region of the handgrip 109, a power switch 131 that energizes and drives the drive motor 111 and an operation member 133 that operates the power switch 131 between an on position and an off position are disposed. The operation member 133 is assembled so that the hand grip 109 is slidable in the horizontal direction (left-right direction) intersecting the long axis direction of the hammer bit, and is slid by the operator's fingers to move the power switch 131 to the on position. Then, the drive motor 111 is energized.

  The rotational output of the drive motor 111 is appropriately converted into a linear motion by the motion conversion mechanism 113 and then transmitted to the striking element 115, and the major axis direction of the hammer bit 119 (the left-right direction in FIG. 1) via the striking element 115. Generates an impact force on. The drive motor 111 is arranged in an intersecting manner so that the axis of the motor shaft 112 crosses the long axis of the hammer bit 119. A motion conversion mechanism 113 that converts the rotational output of the drive motor 111 into a linear motion and transmits it to the striking element 115 is accommodated in the upper region of the internal space of the gear housing 107.

  The motion conversion mechanism 113 converts the rotational motion of the drive motor 111 into a linear motion and transmits it to the striking element 115. The crankshaft 121 that is rotationally driven by the drive motor 111 and the crank plate that rotates together with the crankshaft 121. 124, an eccentric pin 122 provided at a position shifted from the rotation center of the crank plate 124, a crank arm 123 connected through the eccentric pin 122, a piston 125 linearly reciprocated by the crank arm 123, and the like. Consists of a crank mechanism. The piston 125 constitutes a driver for driving the so-called striking element 115, and can slide in the cylinder 141 in the same direction as the major axis direction of the hammer bit 119.

  The crank mechanism is disposed in front of the drive motor 111 and is driven by the drive motor 111 at a reduced speed via the reduction gear mechanism 161. The gear reduction mechanism 161 meshes and engages with a small gear 112a formed on the motor shaft 112, an intermediate gear 163 meshingly engaged with the small gear 112a, an intermediate shaft 165 rotatably supporting the intermediate gear 163, and the intermediate gear 163. The driven gear 167 is mainly used. The driven gear 167 is fixed to the crankshaft 121 so as to rotate integrally. The crankshaft 121 is arranged in an intersecting manner so that its axis crosses the long axis of the hammer bit, and is arranged in parallel with the intermediate shaft 165 with respect to the motor shaft 112. The crank mechanism and the gear reduction mechanism 161 constitute the “drive mechanism” in the present invention. The crank mechanism is housed in a crank chamber 116 that is a sealed internal space in the gear housing 107, and the gear reduction mechanism 161 is placed in a gear chamber 117 that is a sealed internal space above the crank chamber 116 in the gear housing 107. Be contained. The crank chamber 116 and the gear chamber 117 correspond to the “accommodating space” in the present invention.

  The striking element 115 is slidably disposed on the striker 143 slidably disposed on the bore inner wall of the cylinder 141 and the tool holder 137, and transmits the kinetic energy of the striker 143 to the hammer bit 119. And an impact bolt 145 as an intermediate element. An air chamber 141 a is formed in the cylinder 141 between the piston 125 and the striker 143. The striker 143 is driven via an air spring in the air chamber 141a of the cylinder 141 accompanying the sliding movement of the piston 125, and collides (hits) an impact bolt 145 as an intermediate element slidably disposed on the tool holder 137. The striking force is transmitted to the hammer bit 119 via the impact bolt 145.

  During processing of the electric hammer 101 (when the hammer bit 119 is driven), shock and periodic vibration in the long axis direction of the hammer bit occurs in the main body 103. It should be noted that the main vibration as a vibration suppression target generated in the main body 103 is the compression reaction force when the piston 125 and the striker 143 compress the air in the air chamber 141 a, and the striker 143 causes the hammer bit 119 to pass through the impact bolt 145. This is a striking reaction force generated slightly after the compression reaction force when striking.

  As shown in FIG. 2, the electric hammer 101 includes a dynamic vibration absorber 151 as a vibration suppression mechanism that suppresses the vibration generated in the main body 103 and an excitation that forcibly (positively) drives the dynamic vibration absorber 151. A mechanism 171 is provided. The dynamic vibration absorber 151 corresponds to the “dynamic vibration absorber body” in the present invention, and the vibration mechanism 171 corresponds to the “forced drive mechanism” in the present invention.

  As shown in FIG. 4, the dynamic vibration absorber 151 is a state in which a weight 153 and two coil springs 155 and 157, which are a plurality of constituent members, are assembled to the cylinder 141 in advance, that is, a dynamic vibration absorber assembly A1. In the state, as shown in FIGS. 2 and 3, it is assembled to the gear housing 107 and accommodated by the barrel portion 108. The dynamic vibration absorber 151 is mainly composed of an annular damping weight 153 and front and rear coil springs 155 and 157 disposed on the front side and the rear side of the weight 153 in the hammer bit major axis direction, respectively. The coil springs 155 and 157 correspond to the “elastic element” in the present invention.

  The weight 153 is disposed outside the cylinder 141. The front coil spring 155 is interposed between the front end surface of the weight 153 and the front spring receiving sleeve 158 slidably fitted to the outer periphery of the front end of the cylinder 141 in the hammer bit major axis direction. The rear coil spring 157 is interposed between the rear end surface of the rear spring receiving sleeve 159 and the weight 153 which are fitted to the outer periphery of the rear end of the cylinder 141 so as to be slidable in the longitudinal direction of the hammer bit. The front and rear coil springs 155 and 157 act on the weight 153 so as to oppose the urging force in the hammer bit major axis direction. In other words, the weight 153 is movable in the hammer bit axis direction in a state where the urging forces of the front and rear coil springs 155 and 157 act in an opposing manner. As shown in FIG. 3, the front spring receiving sleeve 158 is prevented from coming forward by the front end surface of the small diameter portion 158 c coming into contact with the rear end surface in the major axis direction of the front end large diameter portion 141 b of the cylinder 141. The rear end of the rear spring receiving sleeve 159 is prevented from coming out backward by a retaining ring 142 fitted to the rear outer surface of the cylinder 141.

  The dynamic vibration absorber 151 configured as described above has a front spring receiving sleeve 158, a front coil spring 155, a weight 153, a rear coil spring 157, and a rear spring receiving sleeve with respect to the cylinder 141 before being assembled to the gear housing 107. 159 are fitted from the rear end side of the cylinder 141 in the above order, and a retaining ring 142 is fitted to the rear outer surface of the cylinder 141 so that the cylinder 141 is prevented from coming off and integrated. That is, the dynamic vibration absorber 151 is inserted into the cylinder portion 107a of the gear housing 107 from the front of the gear housing 107 in a state where the dynamic vibration absorber 151 is assembled to the cylinder 141 in advance to form an assembly body A1. As a result, the gear housing 107 is assembled.

  The barrel portion 108 is covered with the cylinder 141 and the dynamic vibration absorber 151 from the front, and the rear end portion is fitted to the outside of the cylindrical portion 107a of the gear housing 107, and then joined by a fastening means such as a screw 114. The Thus, the dynamic vibration absorber 151 is accommodated in a space having an annular cross section between the cylinder 141 and the barrel portion 108. The barrel portion 108 joined to the gear housing 107 has a fitting step portion 108 a that fits with the outer surface of the front end circular portion 158 a of the front spring receiving sleeve 158. That is, the front spring receiving sleeve 158 is interposed between the outer surface of the cylinder 141 and the inner surface of the barrel portion 108 in a state of contacting the outer surface and the inner surface. Thereby, the cylinder 141 and the barrel part 108 are relatively positioned with respect to the radial direction. That is, the cylinder 141 and the barrel portion 108 are held coaxially.

  Further, in front of the front spring receiving sleeve 158, the cylinder 141 is provided with a vent hole 141c for preventing punching in the radial direction and an O-ring 146 as a check valve for closing the vent hole 141c from the outer diameter side. Is provided. When the striker 143 is struck in a no-load state where the hammer bit 119 is not pressed against the workpiece, that is, a load is not applied to the hammer bit 119, the striker 143 is pressed forward by the striker 143. The air in the cylinder 141 flows out through the vent hole 141c while pushing away the O-ring 146. The front spring receiving sleeve 158 has a small hole 158b penetrating in the longitudinal direction of the hammer bit, and the air that is pressed by the striker 143 and flows out of the cylinder 141 passes through the small hole 158b. And the barrel portion 108 are configured to flow out to the rear of the annular space. Therefore, the damper effect of air can be appropriately determined by adjusting the size of the small hole 158b.

  The dynamic vibration absorber 151 mounted on the main body portion 103 has a weight 153 that is a vibration damping element in the dynamic vibration absorber 151 and front and rear coil springs with respect to the main body portion 103 that is the object of vibration suppression when the electric hammer 101 is processed. 155 and 157 cooperate to perform passive vibration suppression. As a result, the vibration generated in the main body 103 of the electric hammer 101 is suppressed.

  Next, the vibration mechanism 171 that actively drives the dynamic vibration absorber 151 will be described. As shown in FIG. 2, the vibration excitation mechanism 171 is disposed directly below the crankshaft 121 and behind the dynamic vibration absorber 151. The vibration exciting mechanism 171 drives the dynamic vibration absorber 151 by linearly operating in the longitudinal direction of the hammer bit based on the cam shaft 172, the circular eccentric cam 173 that rotates together with the cam shaft 172, and the rotational motion of the eccentric cam 173. The power transmission pin 174, bearings 175, 176 that rotatably support the cam shaft 172, and a bearing housing 177 that houses the bearings 175, 176 are mainly configured. The eccentric cam 173 is formed integrally with the cam shaft 172, but may be fixed by press fitting or the like. As shown in FIG. 5, the vibration mechanism 171 is a vibration assembly body A2 in which the above-described components are combined in advance. The vibration assembly body A2 is in the state of the vibration assembly body A2 and is attached to the gear housing 107 of the main body 103 from below. Assembled.

  The cam shaft 172 of the vibration mechanism 171 has a small-diameter portion 172a at the lower portion with the eccentric cam 173 interposed therebetween, a large-diameter portion 172b at the upper portion, and a crank plate 172c above the large-diameter portion 172b. The cam shaft 172 is inserted into the upper and lower bearing housing portions 177a and 177b of the bearing housing 177 from above, and the small diameter portion 172a and the large diameter portion 172b rotate to the bearing housing portions 177a and 177b via the bearings 175 and 176, respectively. It is supported freely. As a result, the cam shaft 172 is integrated with the bearing housing 177 via the bearings 175 and 176. A needle bearing 178 is attached to the outer side of the eccentric cam 173, thereby preventing wear due to sliding with the power transmission pin 174. Further, the crank plate 172c of the cam shaft 172 is formed with an engaging portion 172d made of a U-shaped recess (may be a groove or a long hole) at a position shifted from the center. The engaging portion 172d is engaged with a small-diameter protruding end 122a provided at the lower end of the eccentric pin 122 in the crank mechanism when the vibration assembly A2 is assembled to the gear housing 107 as shown in FIG. To do.

The power transmission pin 174 is constituted by two front and rear pins 174a and 174b arranged in series in the longitudinal direction of the hammer bit, and of the two pins 174a and 174b, an eccentric cam 173 (substantially a needle) One (rear) pin 174 a that abuts the outer ring of the bearing 178 (hereinafter the same) is attached to the bearing housing 177, and the other (front) pin 174 b is attached to the cylindrical portion 107 a of the gear housing 107. One pin 174a, that is, the pin 174a closer to the eccentric cam 173, as shown in FIGS. 5 and 6, intersects with the axis of the cam shaft 172 provided in the bearing housing 177 (hammer bit major axis direction). The pin guide hole 177c is slidably inserted, and the rear end surface as an end portion in the insertion direction is brought into contact with the eccentric cam 173. Thus, one of the power transmission pins 174a 174a is assembled into the pin guide hole 177c of the bearing housing 177, so that the vibration assembly body A2 is obtained.
As shown in FIG. 6, when the eccentric cam 173 is rotated, one pin 174a deviates from the straight line in the longitudinal direction of the hammer bit passing through the center P of the eccentric cam 173 when the eccentric cam 173 is rotated. The thickness is set to have a diameter that is at least twice the eccentric amount e of the eccentric cam 173 (the distance between the center P and the rotation center P1 with respect to the eccentric cam 173). 6A to 6D show a rotational operation mode of the eccentric cam 173 in units of 90 degrees.

The other pin 174b, that is, the pin 174b farther from the eccentric cam 173 is inserted into the pin guide hole 107b in the longitudinal direction of the hammer bit formed in the cylindrical portion 107a of the gear housing 107, as shown in FIGS. It is attached in a penetrating state by inserting from the front. The other pin 174b is attached to the pin guide hole 107b prior to the above-described attachment of the dynamic vibration absorber assembly A1 to the gear housing 107. The front end surface of the other pin 174b in the long axis direction is in contact with the rear end surface of the rear spring receiving sleeve 159 of the dynamic vibration absorber 151, and the vibration assembly body A2 is assembled to the gear housing 107 at the rear end surface of the long axis direction. When it is, it comes into contact with the front end surface of one pin 174a. Further, the other pin 174b is set as thin as possible within a range in which the strength is ensured. That is, the diameter is smaller than that of the one pin 174a, thereby enabling the cylindrical portion 107a to which the barrel portion 108 is attached to be reduced in diameter, and the barrel portion 108 can be reduced in diameter.
If the power transmission pin 174 is composed of one piece, the thickness of one pin 174a is required as a whole, and as a result, the diameter of the cylindrical portion 107a increases, and the barrel portion 108 also increases in diameter accordingly. It will be. However, according to the present embodiment, by configuring the power transmission pin 174 with the two pins 174a and 174b, the diameter of the barrel portion 108 can be reduced while maintaining the operation stability of the power transmission pin 174. The

  The lower portion of the bearing housing portion 177b of the bearing housing 177 has an opening 177d, and an air vent mechanism 181 for adjusting the pressure in the crank chamber 116 is assembled to the opening 177d from below. The air vent mechanism 181 is mainly configured by a filter case 184 having an air passage 182 communicating between the inside and the outside of the crank chamber 116. The filter case 184 has a filter housing chamber, and a filter 183 that adsorbs the lubricating oil that prevents the lubricating oil in the crank chamber 116 from leaking to the outside through the air passage 182 is housed in the filter housing chamber. Yes. The filter case 184 is detachably attached to the opening 177d of the lower bearing housing portion 177b by fitting from below, and is held in the fitting position by friction of the sealing O-ring 185 interposed between the fitting surfaces. . In the present embodiment, a filter case 184 for air bleeding is attached immediately below the cam shaft 172, and at least the inner opening of the air passage 182 is formed on the axis of the cam shaft 172. For this reason, it is difficult for the lubricating oil in the crank chamber 116 to enter the air passage 182 due to the centrifugal force generated by the rotation of the cam shaft 172, and leakage of the lubricating oil can be reduced.

  Further, the bearing housing 177 is formed with an oil supply port 186 for supplying lubricating oil (grease) to the crank chamber 116. A fuel filler cap 187 that closes the fuel filler 186 is removably attached to the fuel filler 186 by fitting from below. The oil filler cap 187 is held at the insertion position by the friction of the sealing O-ring 188 interposed between the fitting surfaces.

  As described above, the vibration assembly A2 includes not only the vibration mechanism 171 but also the air vent mechanism 181 and the fuel filler cap 187. The vibration assembly body A2 having such a structure is inserted from below into a circular opening 107c for mounting formed on the lower surface side of the gear housing 107, that is, the side facing the crank mechanism, and is connected to the crank chamber of the gear housing 107. In this state, the bearing housing 177 is fixed to the gear housing 107 by fixing means such as a screw 189.

  By the way, if the crank mechanism is assembled to the gear housing 107 prior to the assembly operation of the vibration assembly body A2 to the gear housing 107, the cam shaft 172 is used when the vibration assembly body A2 is assembled to the gear housing 107. Alignment work is required for engaging the engaging portion 172d provided on the crank plate 172c with the protruding end portion 122a of the eccentric pin 122 provided on the crank plate 124 of the crank mechanism. That is, when the vibration assembly A2 is attached to the gear housing 107, it is necessary to adjust the circumferential position of the cam shaft 172.

Therefore, in the present embodiment, the angular shaft portion (double surface width) 172e is set at the lower end portion of the cam shaft 172, while the outer surface shape of the angular shaft portion 172e is formed at the insertion direction end portion of the filler cap 187. A square hole 187 a having a corresponding shape is set, and the position of the cam shaft 172 in the circumferential direction can be adjusted using the oil filler cap 187. As a matter of course, the position adjustment operation of the cam shaft 172 is performed at a stage before the filter case 184 is attached to the opening 177d of the lower bearing housing portion 177b, and the oil filler cap 187 is opened in the bearing housing portion 177b. It is formed in a size that can be inserted into 177d and rotated.
Therefore, by adjusting the circumferential position of the cam shaft 172 using the filler cap 187, the engaging portion 172d of the crank plate 172c can be easily engaged with the protruding end portion 122a of the eccentric pin 122 of the crank shaft 121. be able to. As a result, the cam shaft 172 can rotate together with the crank shaft 121. When the vibration assembly A2 is assembled to the gear housing 107, the camshaft 172 is disposed substantially coaxially with the crankshaft 121 of the crank mechanism.

  The vibration assembly body A2 is covered with a cover member 191 attached to the gear housing 107 so as to close the opening 107c on the lower surface side of the gear housing 107. The cover member 191 presses and holds the filter case 184 and the filler cap 187 in the vibration assembly body A2 from below. The cover member 191 extends to a lower region of the motor housing 107 disposed behind the gear housing 107, covers the lower region, and allows the bearing housing portion 105a at the lower portion of the motor housing 107 to be viewed from below. It is set as the structure pressed and hold | maintained. Note that the cover member 191 is fixed to the gear housing 107 with screws not shown for convenience.

  In the electric hammer 101 configured as described above, when the crank mechanism is driven by energization driving of the drive motor 111, the cam shaft 172 of the vibration exciting mechanism 171 is rotationally driven together with the crank shaft 121 of the crank mechanism. The rotation operation of the cam shaft 172 is converted into a linear operation via the eccentric cam 173 and the power transmission pin 174 and input to the dynamic vibration absorber 151. That is, the weight 153 is forcibly driven in the long axis direction of the hammer bit via the rear spring receiving sleeve 159 and the rear coil spring, thereby causing the dynamic vibration absorber 151 to perform a vibration damping action. That is, the dynamic vibration absorber 151 acts as an active vibration damping mechanism by forced vibration that forcibly drives the weight 153 in addition to the above-described passive vibration damping action, and is generated in the main body 103 during the hammering operation. Vibration is suppressed more effectively.

  According to the present embodiment, the weight absorber 153, the front and rear coil springs 155 and 157, and the front and rear spring receiving sleeves 158 and 159, which are constituent members of the dynamic vibration absorber 151, are assembled to the cylinder 141 in advance and the dynamic vibration absorber assembly A1. In this state, the gear housing 107 is assembled. That is, the dynamic vibration absorber 151 can be handled as one part integrated with the cylinder 141, so that the assembling work with respect to the gear housing 107 is facilitated and the assembling property is improved. Moreover, since the removal from the gear housing 107 is also easy, repairability improves.

  In the present embodiment, the camshaft 172, the eccentric cam 173, the bearings 175, 176, and the pin 174a, which are constituent members of the vibration exciting mechanism 171 that actively drives the dynamic vibration absorber 151, are previously attached to the bearing housing 177. The vibration assembly body A2 is assembled to be assembled to the gear housing 107 in this state. For this reason, the vibration mechanism 171 can be handled as one component, so that the assembling work with respect to the gear housing 107 is facilitated, and the assembling property is improved. Moreover, since the removal from the gear housing 107 is also easy, repairability improves.

  In this embodiment, the dynamic vibration absorber assembly A1 is configured by previously assembling the components of the dynamic vibration absorber 151 to the cylinder 141. However, the assembly target is changed to the cylinder 141 and changed to the barrel portion 108. Also good. In this embodiment, the drive motor 111 is described as an electric hammer in which the axis of the motor shaft 112 is arranged so as to cross the long axis of the hammer bit, but the axis of the motor shaft 112 crosses the long axis of the hammer bit. However, the present invention may be applied to an electric hammer of a type in which the drive motor 111 is arranged so as to be away from the long axis of the hammer bit. Moreover, although this Embodiment demonstrated taking the example of the electric hammer as a striking tool, you may apply to the hammer drill in which the hammer bit 119 performs a striking operation | movement and rotation operation | movement.

In view of the gist of the present invention, the following aspects can be configured.
(Aspect 1)
“A striking tool according to claim 2,
The dynamic vibration absorber has a spring receiving sleeve that receives one end of the elastic element, and the spring receiving sleeve is in contact with the outer surface and the inner surface between the outer surface of the cylinder and the inner surface of the barrel portion. An impact tool characterized in that the impact tool is interposed, whereby the cylinder and the barrel are positioned in the radial direction. "
According to the first aspect of the invention, the cylinder and the barrel can be positioned and held coaxially.

(Aspect 2)
“A striking tool according to claim 3,
The impact tool according to claim 1, wherein both ends of the cam shaft are supported by bearings in the assembly. "
According to the invention described in the aspect 2, the rotational operation of the camshaft is stabilized.

It is sectional drawing which shows the whole structure of the electric hammer which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the principal part of an electric hammer. FIG. 3 is a partially enlarged view of FIG. 2. It is an external view which shows a dynamic vibration damper assembly body. It is sectional drawing which shows a vibration assembly body. It is a figure which shows the detail of a power transmission pin.

Explanation of symbols

101 Electric hammer (blow tool)
103 Main body (tool body)
105 Motor housing 105a Bearing housing portion 107 Gear housing 107a Cylindrical portion 107b Pin guide hole 107c Opening portion 108 Barrel portion 108a Fitting step portion 109 Hand grip 111 Drive motor 112 Motor shaft 112a Small gear 113 Motion conversion mechanism 114 Screw 115 Impacting element 116 Crank chamber 117 Gear chamber 119 Hammer bit (tool bit)
121 Crankshaft 122 Eccentric pin 122a Projection end 123 Crank arm 124 Crank plate 125 Piston 131 Power switch 133 Operation member 137 Tool holder 141 Cylinder 141a Air chamber 141b Front end large diameter portion 141c Vent hole 142 Stop ring 143 Strike 145 Impact bolt 146 O Ring 151 dynamic vibration absorber (dynamic vibration absorber body)
153 Weight 155 Front coil spring (elastic element)
157 Rear coil spring (elastic element)
158 Front spring receiving sleeve 158a Front end circular portion 158b Small hole 158c Small diameter portion 159 Rear spring receiving sleeve 161 Gear reduction mechanism 163 Intermediate gear 165 Intermediate shaft 167 Driven gear 171 Excitation mechanism (forced drive mechanism)
172 Cam shaft 172a Small diameter portion 172b Large diameter portion 172c Crank plate 172d Engagement portion 172e Square shaft portion 173 Eccentric cam 174 Power transmission pin 174a One (rear) pin 174b The other (front) pin 175, 176 Bearing 177 Bearing housing 177a Upper bearing housing portion 177b Lower bearing housing portion 177c Pin guide hole 177d Opening 178 Needle bearing 181 Air release mechanism 182 Air passage 183 Filter 184 Filter case 185 O-ring 186 Oil supply port 187 Oil supply port cap 187a Square hole 188 O-ring 189 Screw 191 Cover member A1 Dynamic vibration absorber assembly A2 Excitation assembly

Claims (4)

A striking tool that performs a predetermined hammering operation on a workpiece by a striking motion in the long axis direction of a tool bit,
A motor for driving the tool bit;
A tool body for housing the motor;
A dynamic vibration absorber body for damping the tool body during hammering;
And a forcible drive mechanism that is driven by the motor and forcibly drives the dynamic vibration absorber main body by applying an external force other than the vibration of the tool main body to the dynamic vibration absorber main body during hammering operation. And
At least one of the dynamic vibration absorber main body and the forced drive mechanism is at least one of a plurality of components constituting the dynamic vibration absorber main body and a plurality of components constituting the forced drive mechanism. A striking tool characterized in that one of them is assembled in advance, that is, assembled to the tool body as an assembly. The impact tool according to claim 1,
A barrel part joined to the tool body;
A cylinder accommodated in the barrel portion,
The dynamic vibration absorber main body includes a weight capable of linear movement in the tool bit long axis direction and an elastic element that exerts an urging force in the tool bit long axis direction on the weight, and the weight and the elastic element Is an assembly body by being assembled to either one of the cylinder and the barrel portion. The impact tool according to claim 1 or 2,
The forced drive mechanism portion rotatably supports a cam shaft that is rotationally driven by the motor, an eccentric cam that is integrally formed with or attached to the cam shaft, and at least one end portion in the long axis direction of the cam shaft. A bearing and a bearing housing that accommodates the bearing are combined, and the dynamic vibration absorber main body is forcibly driven by linear movement in the tool bit long axis direction based on the rotational movement of the eccentric cam. Therefore, the assembly has the two pins arranged in series in the tool bit long axis direction, and the pin closer to the eccentric cam is assembled to the bearing housing so as to intersect the axis of the cam shaft. The impact tool characterized by being made into a body. The impact tool according to claim 3,
A drive mechanism that converts the rotational output of the motor into a linear motion to drive the tool bit;
A sealed housing space for housing the drive mechanism,
In the bearing housing, in the state where the bearing housing is assembled to the tool main body portion, an air vent mechanism that communicates the inside and outside of the housing space to adjust the pressure of the housing space and lubricates the housing space. A striking tool comprising an oil filler cap for closing an oil filler opening for supplying oil, whereby an assembly body of the forced drive mechanism is configured.

Images