JP2006062039A - Working tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an effective mounting technique for absorbing dispersion in manufacturing between arrangement intervals of mounting portions and arrangement intervals of mounting portions set on the side of a dynamic vibration absorber, when mounting the dynamic vibration absorber on a working tool. <P>SOLUTION: In this working tool having the dynamic vibration absorber 151, a tube body 153 of the dynamic vibration absorber 151 is constituted of first and second tube parts 161 and 163 connected to be relatively movable in the longitudinal axis direction of the tube body 153, while receiving elastic repulsion force of elastic elements 157 and 159. In the first and second tube parts 161 and 163, mounting parts 167 and 169 mountable on mounted parts 181 provided at prescribed arrangement intervals are provided in a tool main body part. The first and second tube parts 161 and 163 can be displaced to a connected position where the first tube part 161 and the second tube part 163 are mutually connected by at least relative movement in the peripheral direction of the first and second tube parts 161 and 163 and a connection releasing position where the connection is released. At the connected position, the relative movement of the first tube part 161 and the second tube part 163 in a prescribed range of the axial direction is allowed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration damping technique for a work tool that drives a tip tool linearly, such as a hammer or a hammer drill.

  Japanese Patent Application Laid-Open No. 52-109673 (Patent Document 1) discloses a configuration of an electric hammer provided with a vibration damping device. In this conventional electric hammer, an anti-vibration chamber is formed integrally with the main body housing (and the motor housing) in a region below the main body housing and in front of the motor housing. Accommodates a vibration absorber. And it is comprised so that the strong vibration to the hammer major axis direction produced in the case of a hammer drive may be absorbed by the said dynamic vibration absorber.

In the electric hammer disclosed in Patent Document 1, a vibration isolator is set in the main body housing, and the dynamic vibration absorber is accommodated in the vibration isolator. For this reason, it is necessary to directly attach weights, elastic members, and the like, which are constituent members of the dynamic vibration absorber, to the main body housing, and there is still room for improvement when assembling properties are taken into consideration.
By the way, the assembling property of the dynamic vibration absorber to the main body housing as the tool main body, for example, adopts a method in which the dynamic vibration absorber is modularized and this modularized dynamic vibration absorber assembly is attached to the main body housing as the tool main body. You can improve it. In this case, as an attachment structure of the dynamic vibration absorber, for example, if an attachment structure in which the dynamic vibration absorber is attached to the tool main body portion of the work tool at two fixed intervals, the attachment set on the dynamic vibration absorber side is adopted. The accuracy of the arrangement interval of the attached parts set on the tool body side and the tool body part side is extremely important.
JP 52-109673 A

  The present invention, when mounting a dynamic vibration absorber on the tool main body of a work tool, produces an arrangement interval of mounting locations set on the tool main body side and an arrangement interval of mounting locations set on the dynamic vibration absorber side. An object of the present invention is to provide an installation technique that is effective in absorbing variations in the size.

In order to achieve the above object, the invention described in each claim is configured.
According to the first aspect of the present invention, the cylinder, the weight accommodated in the cylinder so as to be movable in the long axis direction of the cylinder, and the elastic element that connects the weight to the cylinder A work tool that performs vibration suppression when the tool bit is driven is configured by the dynamic vibration absorber. The dynamic vibration absorber is a device for reducing the vibration of the vibration control object via a weight connected to the vibration control object via an elastic element or a damping element. The dynamic vibration absorber according to the present invention includes a cylinder, a weight accommodated in the cylinder and accommodated so as to be movable in the longitudinal direction of the cylinder, and each end of the weight connected to the cylinder. And an elastic element. When vibration is generated when the work tool is driven, the weight connected to the cylinder via the elastic element operates in opposition to the vibration to exert a damping action. It is sufficient that the weight is connected to the cylindrical body by at least an elastic element, and a configuration in which the weight is connected to the cylindrical body by a damping element is also included. The “tubular body” in the present invention does not limit the cross-sectional shape.

  The “work tool” in the present invention typically corresponds to a hammer, a hammer drill, or the like, depending on the degree of necessity of vibration suppression by a dynamic vibration absorber. In addition, typically, an electric method or an air method corresponds to the working tool drive format.

  The cylindrical body of the dynamic vibration absorber according to the present invention includes first and second cylindrical portions that are coaxially arranged opposite to each other, and the first cylindrical portion and the second cylindrical portion are connected to the tool main body portion. An attachment portion that can be attached to the attachment portion provided at a predetermined arrangement interval is provided. The first and second cylinder parts are connected to each other at least by a relative movement in the circumferential direction, the connection position where the first cylinder part and the second cylinder part are connected to each other, and the first and second cylinder parts. The first cylinder part and the second cylinder part are allowed to move relative to each other within a predetermined axial range at the connection position. As a result, the axial interval between the attachment portion of the first cylinder portion and the attachment portion of the second cylinder portion can be adjusted to an interval corresponding to the arrangement interval of the attached portions.

  According to the present invention, in the state where the first and second cylindrical portions are connected, that is, in the state where the dynamic vibration absorber is assembled, the arrangement of the mounting portion in the first cylindrical portion and the mounting portion in the second cylindrical portion is arranged. The interval can be changed by relatively moving the first and second cylindrical portions in the major axis direction within an allowable predetermined range. For this reason, even if a manufacturing variation occurs between the arrangement interval of the attachment portion on the tool body side and the arrangement interval of the attachment portion on the dynamic vibration absorber side, the attachment portion is attached while absorbing the variation. Accordingly, it is possible to provide a work tool that contributes to an improvement in the assembly of the dynamic vibration absorber to the tool body. The “allowable predetermined range” in the present invention refers to a range set in consideration of a presumed size of “variation”. Moreover, in this invention, it is the structure by which the said cylinder part is mutually connected or a connection is cancelled | released by relatively moving the 1st cylinder part and the 2nd cylinder part in the circumferential direction. For this reason, it is possible to easily connect or disconnect the first tube portion and the second tube portion, and in the disconnected state, the first tube portion and the second tube portion are separated, and the tube Maintenance and inspection of the weight and the elastic element accommodated in the unit can be performed.

(Invention of Claim 2)
According to invention of Claim 2, each of the 1st cylinder part and the 2nd cylinder part in the work tool of Claim 1 is the said 1st as a means to connect the said 2 cylinder parts mutually. The first and second cylindrical portions have engaging portions that are engaged or disengaged with each other by relative movement in at least the circumferential direction. In the engaged state of the engaging portion, the engaged state is maintained by the elastic force of the elastic element, and the first and second tube portions are long axes in the direction opposite to the direction of the elastic force of the elastic element. It is configured to allow relative movement in the direction. As the “engagement portion” in the present invention, for example, a symmetric key shape (hook shape) that engages and engages with each other by relative movement in the circumferential direction of both tube portions on the opposite end face sides of both tube portions. This embodiment suitably includes an embodiment in which an L-shaped groove extending in the major axis direction and the circumferential direction is provided on one cylindrical portion side, and a protrusion that can be engaged with the other cylindrical portion along the groove. The aspect which provides is included suitably. Further, “maintaining the engaged state” means that the elastic force of the elastic element acts in a direction in which the engaging portion on the first cylindrical portion side and the engaging portion on the second cylindrical portion side are engaged with each other. This is the case.

  According to the present invention, in the engaged state of the engaging portion, the engaged state is maintained by the elastic force of the elastic element. For this reason, the connection state of the 1st cylinder part and the 2nd cylinder part will be fixed (stabilized), and the attachment operation of the attachment part by the side of a dynamic vibration absorber to the attachment part of a tool main part will be simplified. Can be carried out. Further, as a means for maintaining the engaged state of the engaging portion, it is possible to reduce the number of constituent members by using an elastic element used for the vibration damping function of the dynamic vibration absorber. Further, in the engaged state of the engaging portion, the first and second cylindrical portions are allowed to move in the major axis direction opposite to the direction in which the elastic force of the elastic element acts. For this reason, the cylindrical portion side mounting portion is made to coincide with the position of the mounted portion on the tool main body portion side by relatively moving both the cylindrical portions in the major axis direction against the elastic force of the elastic element, and this state The attachment portion can be attached to the attachment portion.

(Invention of Claim 3)
According to the third aspect of the present invention, the first and second cylindrical part mounting portions in the work tool according to the first or second aspect are provided on the outer peripheral surface of the cylindrical part so as to project radially. The connection portion having a vent hole communicating with the internal space of the cylinder portion is configured, and the attached portion provided on the tool main body portion side is configured by a connection port having a vent hole communicating with the internal space of the tool main body portion. Yes. The dynamic vibration absorber is attached to the tool body by fitting the connection port to the connection port, and when the work tool is driven, the weight of the dynamic vibration absorber is the inner space of the first cylindrical portion or the second space. It is set as the structure driven through the fluctuation | variation pressure of the internal space of the tool main-body part introduce | transduced into at least one of the internal space of this cylinder part.
The dynamic vibration absorber is essentially a mechanism in which a weight is driven based on an external vibration input, thereby passively suppressing vibration. In this invention, about the dynamic vibration damper which is this passive vibration suppression mechanism, it is the structure which drives the weight actively via the fluctuation | variation pressure of the internal space of a tool main-body part. Therefore, the dynamic vibration absorber can be steadily operated regardless of the magnitude of vibration acting on the work tool. For this reason, the operator himself / herself is forced to press the work tool strongly despite the high demand for vibration suppression, for example, to perform machining work while applying a strong pressing force to the work tool. As a result, the vibration of the work tool is suppressed, and as a result, the amount of vibration input to the dynamic vibration absorber is small, and even in a work mode in which the dynamic vibration absorber does not operate sufficiently, sufficient vibration suppression is achieved. A work tool capable of securing the function is provided. Here, the “fluctuating pressure in the internal space” typically corresponds to the fluctuating pressure in the crank chamber that houses the crank mechanism used as the drive mechanism for the tool bit. The pressure in the crank chamber fluctuates based on a linear motion of a piston that is a final drive member in the crank mechanism. By introducing this fluctuating pressure into the internal space of the dynamic vibration absorber, the weight can be actively driven.

  In the present invention, the attachment portions of the first and second cylindrical portions are configured by connection ports provided in a protruding shape in the radial direction on the outer surface of the cylindrical portion. And the said connection port is set as the structure which connects the internal space of a cylinder part, and the internal space of a tool main-body part by fitting in the to-be-connected port as a to-be-attached part provided in the tool main-body part side. According to such a configuration, the piping work connecting the internal space on the dynamic vibration absorber side and the internal space on the tool body side is performed simultaneously by performing the work of attaching the dynamic vibration absorber to the tool body portion. Become. For this reason, piping work after assembling the dynamic vibration absorber to the tool main body is not necessary, and the assemblability is further improved.

(Invention of Claim 4)
According to invention of Claim 4, the 1st and 2nd cylinder part in the working tool in any one of Claims 1-3 is relative to the said cylinder part, receiving the elastic force of an elastic element. And each elastic element receiving member is fixed to the tool main body through a relative movement operation with respect to the first and second cylindrical portions. . According to such a configuration, since the dynamic vibration absorber can be attached to the tool main body using the elastic force of the elastic element, it can be rationally attached with fewer parts than a fastening structure using screws, for example. Realized. Further, the elastic force of the elastic element is configured not to act on the first and second cylindrical portions, so that the elastic force of the elastic element is avoided from acting on the mounting portion, and the mounting portion is protected. Is possible.

  According to the present invention, when the dynamic vibration absorber is attached to the tool main body of the work tool, the mounting interval between the mounting positions set on the tool main body side and the mounting interval between the mounting positions set on the dynamic vibration absorber side. An effective mounting technique for absorbing manufacturing variations was provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In the embodiment of the present invention, an electric hammer drill will be described as an example of a work tool. 1 to 3 mainly show the external configuration of the hammer drill 101 as a whole, FIGS. 4 to 6 show a structure for mounting a dynamic vibration absorber, and FIGS. 7 and 8 show the structure of the dynamic vibration absorber. Has been. As shown in FIG. 1 to FIG. 3, the hammer drill 101 according to the present embodiment generally has a main body 103 that forms an outline of the hammer drill 101, and a tool holder 137 through a tip region of the main body 103. The main body is composed of a hammer bit 119 that is detachably attached. 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 main body 103 of the electric hammer drill 101 is roughly divided into a motor housing 105 that houses a drive motor 111 (see FIG. 3), a crank housing 107 that houses a motion conversion mechanism constituted by a crank mechanism, although not particularly shown for convenience, and a gear. A gear housing 108 (see FIG. 3) that houses a power transmission mechanism and the like constituted by the apparatus, a barrel housing 106 that houses a striking element made up of a striker and an impact bolt, and a hand grip 109. The rotation output of the drive motor 111 is appropriately converted into a linear motion by a motion conversion mechanism and then transmitted to the striking element, and the impact in the major axis direction (left and right direction in FIG. 1) of the hammer bit 119 is transmitted through the striking element. Generate power. The rotational output of the drive motor 111 is appropriately decelerated by the power transmission mechanism and then transmitted as a rotational motion to the hammer bit 119, and the hammer bit 119 is rotated in the circumferential direction. In addition, the hammer drill 101 is operated by an operator as appropriate, so that only a striking force in the long axis direction is applied to the hammer bit 119 to perform processing of the workpiece, and so-called hammer mode and striking in the long axis direction. It is possible to switch between a so-called hammer drill mode in which a workpiece is processed by applying a force and a rotational force in the circumferential direction. FIG. 2 shows a hammer mode switching lever 113.

  Details of hammer drive that applies hammering force in the major axis direction to hammer bit 119, hammer drill drive that applies hammering force in the major axis direction and rotational force in the circumferential direction, and modes between hammer mode and hammer drill mode The details of the switching are known matters and are not directly related to the present invention, so that the description thereof is omitted.

  In the upper region of the main body 103 of the hammer drill 101, dynamic vibration absorber accommodating spaces 115 are formed on the left and right sides of the long axis of the hammer bit 119, respectively, and the dynamic vibration absorber 151 is formed in the left and right dynamic vibration absorber accommodating spaces 115. Is arranged. The detailed structure of the dynamic vibration absorber 151 is shown in FIGS. The structure of the dynamic vibration absorber 151 is the same for both the left and right dynamic vibration absorbers 151. The dynamic vibration reducer 151 includes a cylindrical body 153 formed in an elongated hollow shape, a weight 155 disposed in the cylindrical body 153, and the weight 155 illustrated so as to connect the weight 155 to the cylindrical body 153. The biasing springs 157 and 159 arranged on the left and right are mainly configured. The biasing springs 157 and 159 correspond to “elastic elements” in the present invention.

  The cylindrical body 153 includes a cylindrical first cylindrical portion 161, a cylindrical second cylindrical portion 163, and a cylindrical inner cylinder 165. The first cylinder part 161 and the second cylinder part 163 are fitted to the outer peripheral surface of the inner cylinder 165 so as to be slidable in the circumferential direction and the long axis direction. As a result, the first tube portion 161 and the second tube portion 163 are arranged coaxially and are relatively movable in the long axis direction of the tube body 165. A seal 164 for preventing air leakage is interposed between the fitting surfaces of the inner cylinder 165, the first cylinder part 161, and the second cylinder part 163. The first cylindrical portion 161 corresponds to the “first cylindrical portion” in the present invention, and the second cylindrical portion 163 corresponds to the “second cylindrical portion” in the present invention.

  The first cylindrical portion 161 and the second cylindrical portion 163 are connected to each other at one end in the major axis direction facing each other via key-shaped (hook-shaped) engaging portions 161a and 163a that engage with each other. Is done. The engaging portion 161a of the first tube portion 161 and the engaging portion 163a of the second tube portion 163 are extended from the end surface of the tube portion by a predetermined length in the major axis direction, and both the tube portions 161 and 163 are mutually connected. In the approached state (the state where the end face of the cylinder part and the tip of the engaging part are in contact with each other), the two cylinder parts 161 and 163 are engaged with each other by relative movement in the circumferential direction, whereby the first cylinder part is engaged. 161 and the 2nd cylinder part 163 are connected. Therefore, if the first cylinder part 161 and the second cylinder part 163 are relatively moved in the circumferential direction opposite to the above, the meshing engagement between the engaging parts 161a and 163a is released, and the first cylinder part 161 is released. And the connection of the 2nd cylinder part 163 is cancelled | released. FIG. 7 shows a state before the first tube portion 161 and the second tube portion 163 are connected, that is, a connection release state, and FIG. 8 shows that the first tube portion 161 and the second tube portion 163 are connected. The state, that is, the assembled state of the dynamic vibration absorber 151 is shown.

  The meshing engagement operation of the engaging portions 161a and 163a performed to connect the first cylindrical portion 161 and the second cylindrical portion 163 is performed while resisting the elastic force of the biasing springs 157 and 159. . And in the connection state of both the cylinder parts 161 and 163 in which the engaging parts 161a and 163a are engaged and engaged with each other, as shown in FIG. 8, the long axis direction end faces of the first cylinder part 161 and the second cylinder part 163, Predetermined gaps C are respectively set between the end faces of the engaging parts 163a facing each other, and the first cylinder part 161 and the second cylinder part 163 are in the major axis direction within the range of the gaps C. Relative movement is possible. Thus, the entire cylinder 153 can be expanded and contracted in the major axis direction within the range of the gap C. In addition, regarding the size of the gap C, a manufacturing variation between an arrangement interval of the connection ports 181 on the main body 103 side, which will be described later, and an arrangement interval of the connection ports 167 and 169 on the dynamic vibration absorber 151 side is considered. Is set.

  On the outside of the first cylinder portion 161 and the second cylinder portion 163, connection ports 167 and 169 having air vent holes 167a and 169a are provided in a protruding shape in the radial direction, and the connection ports 167 and 169 are It is set as the structure connected to the to-be-connected port 181 which has the ventilation hole 181a of the air provided in the main-body part 103 of the electric hammer drill 101. FIG. In a state before the dynamic vibration absorber 151 is attached to the main body portion 103, as described above, the cylinder body 153 is held in the state (the state shown in FIG. 8) extended to the maximum by the elastic force of the biasing springs 157 and 159. Therefore, at this time, the arrangement interval between the connection ports 167 and 169 is maximized. And the arrangement | positioning space | interval of both the connection ports 167 and 169 can be adjusted through the relative movement of the 1st cylinder part 161 and the 2nd cylinder part 163 in the axial direction. Further, the connection port 167 of the first tube portion 161 and the connection port 169 of the second tube portion 163 are engaged with the engagement portion 161a of the first tube portion 161 and the engagement portion 163a of the second tube portion 163, so that both tubes In the state shown in FIG. 8 in which the parts 161 and 163 are connected, the positions in the circumferential direction coincide with each other, that is, they are set on the same straight line in the axial direction of the cylindrical body 153. The connection ports 167 and 169 correspond to the “attachment portion” in the present invention, and the connection port 181 corresponds to the “attachment portion” in the present invention.

  In addition, spring receivers 171 and 173 that receive the resilient force of the biasing springs 157 and 159 are provided at the other end portions in the major axis direction of the first and second cylindrical portions 161 and 163, respectively. Is fitted to the inner circumferences of the other end portions of the first and second cylindrical portions 161 and 163 so as to be relatively movable in the major axis direction (left and right direction in the drawing) of the first and second cylindrical portions 161 and 163. Yes. The spring receivers 171 and 173 always come out of the first and second cylindrical portions 161 and 163 by contacting the stepped surfaces provided on the inner peripheral surfaces of the first and second cylindrical portions 161 and 163. It is regulated. The spring receivers 171 and 173 are provided with stoppers 175 and 177, respectively, and the movement range of the weight 155 is regulated by the stoppers 175 and 177. A seal 172 for preventing air leakage is interposed between the fitting surfaces of the spring receivers 171 and 173 and the first and second cylindrical portions 161 and 163. The spring receivers 171 and 173 correspond to the “elastic element receiving member” in the present invention.

  The weight 155 has a large-diameter portion 155a and small-diameter portions 155b located on both sides of the large-diameter portion 155a, and the large-diameter portion 155a slides on the inner peripheral surface of the inner cylinder 165. Biasing springs 157 and 159 are disposed on both sides of the large diameter portion 155a in the moving direction, respectively. The biasing springs 157 and 159 are compression coil springs, one end of which is in contact with the spring receivers 171 and 173, and the other end is in contact with the end surface in the major axis direction of the large diameter portion 155 a of the weight 155. As a result, the biasing springs 157 and 159 impart an opposing elastic force to the weight 155 when the weight 155 moves in the long axis direction of the cylindrical body 153 (the long axis direction of the hammer bit 119).

  In order to attach the dynamic vibration absorber 151 configured as described above to the main body portion 103 of the electric hammer drill 101, the side surfaces of the right side surface and the left side surface of the main body portion 103 across the major axis of the hammer bit 119 are respectively Each of the two connected ports 181 and the two fastening members 183 are provided. Each of the two connected ports 181 is set to be connected to the connection ports 167 and 169 of the dynamic vibration absorber 151, and is arranged at a predetermined interval in a direction parallel to the major axis direction of the hammer bit 119. Each of the two fastening members 183 is set so as to latch and hold the spring receivers 171 and 173 of the dynamic vibration absorber 151, and is arranged to face each other in a direction parallel to the major axis direction of the hammer bit 119. Yes.

  As shown in FIGS. 4 and 5, the connected port 181 is provided integrally with the inner housing 117, and has a fitting recess 181 b into which the connecting ports 167 and 169 of the dynamic vibration absorber 151 can be fitted. The fitting recess 181b is open in the side surface direction. That is, the connection port 167 and 169 of the dynamic vibration absorber 151 are fitted to the connected port 181 by moving the dynamic vibration absorber 151 substantially horizontally from the side of the main body portion 103 toward the side surface of the main body portion 103. It is the structure which is fitted and connected to the recessed part 181b.

  As shown in FIGS. 4 and 5, the two fastening members 183 are formed in a substantially L shape in plan view by bending an iron plate and are fixedly attached to the inner housing 117. The fastening member 183 has a locking recess 183b in which the ends of the spring receivers 171 and 173 are locked to a counter plate 183a extending in a direction parallel to the fitting direction of the connection ports 167 and 169. Based on the moving operation when moving the dynamic vibration absorber 151 so as to fit the connection ports 167 and 169 of the dynamic vibration absorber 151 into the connected port 181, the spring receivers 171 and 173 of the dynamic vibration absorber 151 are arranged to face each other. In addition to being inserted between the opposing plates 183a of the fastening member 183, the ends of the spring receivers 171 and 173 are engaged with the engaging recesses 183b of the opposing plate 183a, whereby the cylindrical body 153 of the dynamic vibration absorber 151 is It is fixed to the fixing member 183. Thus, the dynamic vibration absorber 151 is attached to the main body 103 such that the long axis direction of the cylindrical body 153 is parallel to the long axis direction of the hammer bit 119.

  When the spring receivers 171 and 173 are inserted between the opposing plates 183a of the fastening member 183, the spring receivers 171 and 173 attached to the first and second cylindrical portions 161 and 163 so as to be relatively movable are biased springs 157 and 157, respectively. It is pushed into the first and second cylindrical portions 161 and 163 against 159. For this reason, in the state where the dynamic vibration absorber 151 is attached to the main body 103, the resilient force of the biasing springs 157 and 159 is received by the fastening member 183 via the spring receivers 171 and 173, and the first Further, the resilient force of the urging springs 157 and 159 does not act on the second cylindrical portions 161 and 163. As a result, it is possible to avoid the elastic force of the biasing springs 157 and 159 acting on the connection ports 167 and 169 fitted to the connection port 181 in the radial direction of the connection ports 167 and 169.

  Inclined surfaces 171a and 173a (see FIG. 4) which are inclined inward in the insertion direction with respect to the opposing plate 183a are provided at the distal ends of the spring receivers 171 and 173, and outwardly at the insertion side end of the opposing plate 183a. An inclined portion 183c that is inclined is formed, thereby facilitating the insertion operation of the spring receivers 171 and 173 between the opposed plates 183a. As shown in FIG. 3, the dynamic vibration absorber accommodation space 115 is closed by a cover 191 and is hidden so that the dynamic vibration absorber 151 attached to the main body 103 as described above cannot be seen from the outside. .

  Each of the two connected ports 181 on the main body 103 side connected to the connection ports 167 and 169 of the dynamic vibration absorber 151 has a vent hole 181a. As schematically shown in FIG. 5, the vent hole 181a of one of the connected ports 181 is an internal sealed space of the main body 103, specifically, an internal space of the crank housing 107 that houses the motion conversion mechanism and the like. The vent hole 181a of the other connected port 181 communicates with a certain crank chamber 185, and the internal sealed space of the main body 103, specifically, the gear housing 108 that houses the power transmission mechanism, the striker, and the piston are slidable. Is communicated with a cylinder housing space 187 surrounded by a barrel housing 106 that houses a cylinder to be fitted into the cylinder. That is, among the internal spaces formed on both sides of the weight 155 of the dynamic vibration absorber 151, the working chamber 151a on the first tube portion 161 side, which is one of the internal spaces, communicates with the crank chamber 185 and the other internal space. The working chamber 151 b on the second cylinder portion 163 side is in communication with the cylinder housing space 187.

The operation of the hammer drill 101 configured as described above will be described. When the drive motor 111 shown in FIG. 3 is energized and driven, its rotational output is converted into a linear motion via the motion conversion mechanism, and then the hammer bit 119 is linearly moved in the major axis direction via the striking mechanism. Make the hammer move. Further, in addition to the above-described hammer operation, the hammer bit 119 is transmitted with a rotation operation through a power transmission mechanism driven by the rotation output of the drive motor 111, and thus a drill operation in the circumferential direction is applied. That is, when the hammer drill 101 is driven in the hammer drill mode, the hammer bit 119 performs a hammer operation in the long axis direction and a drill operation in the circumferential direction, and performs a hammer drilling operation on the workpiece.
When the hammer drill 101 is driven in the hammer mode, the rotational power transmission is interrupted via a clutch provided in the middle of the rotational power transmission system in the power transmission mechanism. For this reason, when driving in the hammer mode, the hammer bit 119 performs only a hammer operation in the long axis direction, and performs a hammering operation on the workpiece.

  As described above, the dynamic vibration absorber 151 provided in the main body 103 has a vibration damping function against shocking and periodic vibration generated when the hammer bit 119 is driven. That is, when the main body portion 103 of the hammer drill 101 is regarded as a vibration suppression target body to which a predetermined external force (vibration) acts, the vibration damping element in the dynamic vibration absorber 151 with respect to the main body portion 103 that is the vibration suppression target body. The weight 155 and the biasing springs 157 and 159 cooperate to perform passive vibration suppression. Thereby, the vibration of the electric hammer 101 in the present embodiment is effectively suppressed. Since the vibration damping principle itself by the dynamic vibration absorber 151 is a known matter, a detailed description thereof is omitted.

  In the present embodiment, the working chamber 151 a of the first cylindrical portion 161 in the dynamic vibration absorber 151 communicates with the crank chamber 185, and the working chamber 151 b of the second cylindrical portion 163 communicates with the cylinder housing space 187. The crank chamber 185 is a sealed space that is cut off from the outside, and the pressure in the crank chamber 185 varies with the drive of the motion conversion mechanism. This is based on the fact that the piston, which is a component of the motion conversion mechanism, linearly moves in the cylinder. That is, when the piston moves forward (when the hammer bit 119 moves in the long axis direction to perform hammering), the pressure in the crank chamber 185 decreases based on the expansion of the volume of the crank chamber 185 due to the piston moving forward, When the piston moves backward, the volume of the crank chamber 185 is reduced and the pressure is increased.

  On the other hand, the cylinder housing space 187 is not communicated with the crank chamber 185 but is an independent sealed space. When the piston is moved forward, the striker, which is a component of the striking mechanism, is moved forward in the cylinder via the air spring and applies an impact force to the hammer bit via the impact bolt. And the space in the cylinder between the impact bolts is reduced, and accordingly, the air in the cylinder space is pushed out from the vent hole formed in the cylinder into the cylinder housing space 187. For this reason, the pressure in the cylinder housing space 187 increases. When the striker returns to the initial position, the air in the cylinder housing space 187 is sucked into the cylinder inner space based on the expansion of the cylinder inner space, thereby reducing the pressure in the cylinder. The striker corresponds to the “stroker” in aspect 1, the crank chamber corresponds to the “first internal space” in aspect 1, and the cylinder housing space corresponds to the “second internal space” in aspect 1. ".

  As described above, when the hammer drill 101 is driven, the pressure in the crank chamber 185 and the cylinder housing space 187 fluctuates with the drive of the motion conversion mechanism or the striking mechanism, and the pressure fluctuation has a phase difference of approximately 180 degrees. Is. That is, when the pressure in the crank chamber 185 increases, the pressure in the cylinder housing space 187 decreases, and when the pressure in the crank chamber 185 decreases, the pressure in the cylinder housing space 187 increases. In the present embodiment, the pressure of the internal space of the main body 103 that varies in this way is introduced into the working chambers 151a and 151b of the first and second cylindrical portions 161 and 163 of the dynamic vibration absorber 151. That is, a configuration in which the dynamic vibration absorber 151 is subjected to a vibration damping action by a so-called forced vibration method that actively drives the weight 155 of the dynamic vibration absorber 151 using the fluctuating pressure in the crank chamber 185 and the cylinder housing space 187. It is.

  When the hammer drill 101 is driven, when the piston advances and the hammer bit 119 is hammered via the striker, the pressure in the crank chamber 185 decreases and the pressure in the cylinder housing space 187 increases (however, they coincide with each other in time). Not a thing, but with a gap). Accordingly, a suction force acts on the weight 155 of the dynamic vibration absorber 151 in the working chamber 151a of the first cylinder portion 161, and a pressing force acts on the working chamber 151b side of the second cylinder portion 163. As a result, the weight 155 is moved in a direction (right side in the figure) opposite to the movement direction of the striker. That is, the dynamic vibration absorber 151 acts as an active vibration suppression mechanism by forced vibration that actively drives the weight 155 and can effectively suppress vibration generated in the main body 103 during hammering.

  On the other hand, when the piston is retracted, that is, when the striker is retracted, as described above, the pressure in the crank chamber 185 increases and the pressure in the cylinder housing space 187 decreases. As a result, a pressing force acts on the weight 155 of the dynamic vibration absorber 151 in the working chamber 151 a of the first cylinder portion 161, and a suction force acts on the working chamber 151 b side of the second cylinder portion 163. As a result, the weight 155 is moved in a direction (left side in the figure) opposite to the movement direction of the striker. That is, the dynamic vibration absorber 151 effectively acts as an active vibration suppression mechanism by forced vibration that actively drives the weight 155 even when the striker moves backward.

  As described above, according to the present embodiment, the weight 155 is driven based on the vibration input from the outside (hammer drill 101 side), and this is a mechanism that passively suppresses the vibration. For the vibration absorber 151, the weight 155 is a forced vibration system that is actively driven so as to oppose the linear motion of the striker 143 using the fluctuating pressure in the internal space of the main body 103. As a result, the dynamic vibration absorber 151 can be steadily operated regardless of the magnitude of vibration acting on the hammer drill 101. As a result, for example, the operator performs a hammering operation or a hammer drilling operation while applying a strong pressing force to the hammer drill 101, but the vibration absorber 151 has a high demand for vibration suppression. Even in a work mode in which the amount of vibration input becomes small and the dynamic vibration absorber 151 does not operate sufficiently, the weight 153 can be actively driven to ensure a sufficient vibration damping function. .

  In the present embodiment, when the forced vibration type modular dynamic vibration absorber 151 using the fluctuating pressure as described above is attached to the main body portion 103, the connection port provided in the cylinder 153 of the dynamic vibration absorber 151 is provided. By inserting 167 and 169 into the connected port 181 provided on the main body 103 side, the working chambers 151 a and 151 b that are the internal space of the dynamic vibration absorber 151 are the crank chamber 185 that is the internal space of the main body 103. And it is set as the structure connected to the cylinder accommodation space 187 simultaneously. According to such a configuration, after assembling the dynamic vibration absorber 151 to the main body portion 103, the working chambers 151a and 151b of the dynamic vibration absorber 151 are purposely connected to the crank chamber 185 and the cylinder housing space 187 of the main body portion 103. Therefore, troublesome piping work is not required, and the efficiency of assembly work can be improved.

  In this case, there may be a manufacturing variation in the arrangement interval of the two connection ports 167 and 169 on the dynamic vibration absorber 151 side and the arrangement interval of the connection port 181 on the main body 103 side. In the present embodiment, in order to cope with the occurrence of such variation, the cylindrical body 153 of the dynamic vibration absorber 151 is constituted by the first cylindrical portion 161 and the second cylindrical portion 163 provided with the connection ports 167 and 169, respectively. The two cylinder portions 161 and 163 are connected to each other through the engaging portions 161a and 163a so as to be relatively movable in the major axis direction while receiving the elastic force of the biasing springs 157 and 159. When the connection ports 167 and 169 are fitted into the connection port 181, the longitudinal direction of the first and second tube portions 161 and 163 is within the range of the gap C set in the engagement portions 161 a and 163 a. The arrangement interval can be adjusted (changed) through relative movement. That is, the position shift of the connection ports 167 and 169 with respect to the connection port 181 is absorbed. Therefore, even if manufacturing variations occur between the arrangement interval of the connection ports 167 and 169 on the dynamic vibration absorber 151 side and the arrangement interval of the connection port 181 on the main body 103 side, the first and second cylinder portions 161 are provided. , 163 can be attached to the connected port 181 without any trouble while absorbing the variation within the range of the gap C in which the relative movement in the major axis direction is allowed.

  The first and second cylindrical portions 161 and 163 are connected via engaging portions 161a and 163a that engage and engage with each other by relative movement (rotation operation) in the circumferential direction, and are relatively opposite to each other. It is the structure by which connection is cancelled | released by moving. Therefore, the first cylinder part 161 and the second cylinder part 163 can be easily connected or disconnected without using a special tool, and in the disconnected state, the first cylinder part 161 and the second cylinder part are connected. 163 and the inside weight 155 and the elastic elements 157 and 159 can be inspected and maintained.

  In the present embodiment, the spring receivers 171 and 173 that receive the resilient force of the biasing springs 157 and 159 are fitted to the first and second cylindrical portions 161 and 163 so as to be movable relative to each other. The receivers 171 and 173 are configured to be fixed to the fixing member 183 of the main body 103 through a relative movement operation with respect to the first and second cylindrical portions 161 and 163. According to such a configuration, since the dynamic vibration absorber 151 can be attached to the main body 103 using the elastic force of the biasing springs 157 and 159, it can be mounted rationally with fewer parts than a fastening structure such as a screw. Can be easily removed as necessary, which is advantageous for maintenance and inspection work. In addition, the elastic force of the biasing springs 157 and 159 does not act on the first and second cylindrical portions 161 and 163, so that it is avoided that the resilient force acts on the connection ports 167 and 169. The connection ports 167 and 169 can be protected.

  Note that, in the above-described embodiment, the forced vibration type that actively drives the weight 155 of the dynamic vibration absorber 151 using the fluctuating pressure in the internal space of the main body 103 has the relationship described on the main body 103 side. The mounting portion is composed of the connected port 181 having the vent hole 181a, and the mounting portion of the dynamic vibration absorber 151 is composed of the connecting ports 167 and 169 having the vent holes 167a and 169a. Is not limited to the connected port 181 and the connecting ports 167 and 169. In the above-described embodiment, the hammer drill 101 is described as an example of the working tool. However, the present invention is not limited to the hammer drill 101, and can naturally be applied to a hammer. Any work tool that performs a machining operation can be applied. For example, it can be suitably used for a jigsaw or a reciprocating saw that performs a cutting operation of a workpiece by reciprocating a saw blade linearly.

In view of the gist of the invention, the following aspects can be configured.
In a conventional dynamic vibration absorber disclosed in, for example, Japanese Patent Application Laid-Open No. 52-109673, a weight placed in a state where an urging force by an elastic element is applied acts on the magnitude of vibration input to the dynamic vibration absorber. The vibration control action is achieved by being driven according to the above. That is, the dynamic vibration absorber has a passive characteristic that the amount of vibration suppression is determined according to the amount of vibration generated. By the way, in an actual machining operation, vibrations are suppressed because a considerable load is applied to the tool bit from the workpiece side, such as when an operator works with the work tool pressed strongly against the workpiece side. However, there is a case where the amount of vibration input to the dynamic vibration absorber is suppressed in spite of a high demand.
The invention of Aspect 1 has been made in view of such a point, and an object thereof is to provide a technique that contributes to further improving the vibration damping performance of a work tool.

(Aspect 1)
“With the tool bit,
A drive motor;
A motion conversion mechanism for converting the rotational output of the drive motor into linear motion in the tool bit long axis direction;
A first internal space in which the pressure varies based on the operation of the motion conversion mechanism;
A striking element that is driven linearly by the motion conversion mechanism and applies an impact force in the long axis direction to the tool bit, thereby causing the tool bit to perform a predetermined machining operation;
A second internal space in which the pressure varies based on the operation of the striker;
A work tool having a dynamic vibration absorber for damping vibration during a machining operation using the tool bit,
The dynamic vibration absorber has a weight configured to be capable of linear motion in a state in which urging forces of a plurality of elastic elements act in an opposing manner, and the weight includes a fluctuating pressure introduced from the first internal space, The working tool is configured to be driven in both directions by the fluctuating pressure introduced from the second internal space. "

  According to the invention described in the aspect 1, the work tool having the tool bit, the drive motor, the motion conversion mechanism, the first internal space, the striker, the second internal space, and the dynamic vibration absorber is configured. Is done. The motion conversion mechanism converts the rotational output of the drive motor into linear motion in the tool bit long axis direction. The striker is driven linearly by a motion conversion mechanism to apply an impact force in the major axis direction to the tool bit, thereby causing the tool bit to perform a predetermined machining operation. Typically, a hammer bit corresponds to this tool bit. In the first internal space, when the motion conversion mechanism is driven, the pressure varies based on the operation of the motion conversion mechanism. The “first internal space” typically corresponds to a crank chamber that houses a crank mechanism as a motion conversion mechanism. The crank chamber is accompanied by a change in pressure based on a linear movement of a piston, which is a component of the crank mechanism, in the cylinder. When the striker is driven, the pressure in the second internal space varies based on the operation of the striker. The “second internal space” typically corresponds to a cylinder housing space that houses a cylinder that guides the linear motion of the striker. The cylinder housing space is accompanied by a pressure change based on the air in the cylinder flowing into or out of the cylinder housing space by the linear movement of the striker.

  The dynamic vibration absorber in the present invention has a weight configured to be capable of linear motion in a state where an urging force by an elastic element is applied. The weight, which is an element of the dynamic vibration absorber, is sufficient if at least an urging force by an elastic element is applied, and further includes a configuration in which the action of a damping force by a damping element is received.

  As a feature of the present invention, the weight of the dynamic vibration absorber is configured to be driven in both directions by the fluctuating pressure introduced from the first inner space and the fluctuating pressure introduced from the second inner space. The dynamic vibration absorber is essentially a mechanism in which a weight is driven based on an external vibration input, thereby passively suppressing vibration. In the present invention, the weight of the dynamic vibration absorber, which is such a passive vibration damping mechanism, is positively driven by fluctuating pressure due to the operation of the motion conversion mechanism for driving the tool bit and the striker. Therefore, the dynamic vibration absorber can be steadily operated regardless of the magnitude of vibration acting on the work tool. For this reason, for example, the amount of vibration input to the dynamic vibration absorber is small even though the demand for vibration suppression is high, such as when a machining operation is performed while applying a strong pressing force to the work tool, and the dynamic vibration absorber Even in a work mode in which the motor does not operate sufficiently, it is possible to ensure a sufficient vibration damping function. In particular, by actively driving the weights in both directions, it is possible to provide a vibration damping action for both the stroke in which the striker moves in the direction of applying an impact force to the tool bit and the stroke returning to the initial position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cut side view showing an overall external configuration of an electric hammer drill according to an embodiment of the present invention. It is a partial cutting top view which similarly shows the external appearance whole structure of a hammer drill. It is a partially cut rear view which similarly shows the overall appearance configuration of the hammer drill. It is a plane sectional view which shows the attachment structure of the dynamic vibration absorber with respect to a main-body part, and the state before attaching is shown. It is a plane sectional view which similarly shows the attachment structure of the dynamic vibration absorber with respect to a main-body part, and the attached state is shown It is a longitudinal cross-sectional view which similarly shows the attachment structure of the dynamic vibration absorber with respect to a main-body part. It is an external view which shows the structure of the dynamic vibration absorber by which the 2nd cylinder part was cut away from the 1st cylinder part. It is an external view which shows the assembled dynamic vibration absorber.

Explanation of symbols

101 Hammer drill (work tool)
103 Body 105 Motor housing 106 Barrel housing 107 Crank housing 108 Gear housing 109 Hand grip 111 Drive motor 113 Mode switching lever 115 Dynamic vibration absorber housing space 117 Inner housing 119 Hammer bit (tool bit)
137 Tool holder 151 Dynamic vibration absorber 151a, 151b Working chamber 153 Cylindrical body 155 Weight 155a Large diameter part 155b Small diameter part 157, 159 Biasing spring (elastic element)
161 1st cylinder part (1st cylinder part)
161a Engagement part 163 2nd cylinder part (2nd cylinder part)
163a Engagement part 164 Seal 165 Inner cylinder 167,169 Connection port (attachment part)
167a, 169a Ventilation holes 171, 173 Spring receiver (elastic element receiving member)
171a, 173a Inclined surface 172 Seals 175, 177 Stopper 181 Connected port (attached part)
181a Vent hole 181b Fitting recess 183 Fastening member 183a Opposing plate 183b Locking recess 183c Inclined portion 185 Crank chamber 187 Cylinder housing space 191 Cover

Claims (4)

When a tool bit is driven by a dynamic vibration absorber having a cylinder, a weight accommodated in the cylinder so as to be movable in the axial direction of the cylinder, and an elastic element connecting the weight to the cylinder A work tool for damping
The cylindrical body of the dynamic vibration absorber is composed of first and second cylindrical portions arranged coaxially and opposed to each other, and on the outer peripheral surface of the first cylindrical portion and the outer peripheral surface of the second cylindrical portion. In addition, an attachment portion that can be attached to the attachment portion provided at a predetermined arrangement interval in the tool body portion is provided,
The first and second tube portions are connected at positions where the first tube portion and the second tube portion are connected to each other by relative movement of the first and second tube portions in at least the circumferential direction. And can be displaced to a connection release position at which the connection is released. At the connection position, the first cylinder part and the second cylinder part are allowed to move relative to each other within a predetermined range in the axial direction. A work tool characterized in that an axial interval between the attachment portion of the first tube portion and the attachment portion of the second tube portion can be adjusted to an interval corresponding to the arrangement interval of the attached portions. . The work tool according to claim 1,
Each of the first tube portion and the second tube portion is engaged with each other by means of relative movement in at least the circumferential direction of the first and second tube portions as means for connecting the tube portions to each other. The engagement portion is engaged or disengaged, and in the engagement state of the engagement portion, the engagement state is maintained by the elastic force of the elastic element, and the first and second tube portions are elastic A work tool characterized in that it is allowed to relatively move in an axial direction opposite to the direction in which the elastic force of an element acts. The work tool according to claim 1 or 2,
The attachment part of the first cylinder part and the attachment part of the second cylinder part are provided on the outer peripheral surface of the cylinder part so as to project radially, and have a vent hole communicating with the internal space of the cylinder part The mounted portion provided on the tool main body portion side is configured by a connected port having a vent hole communicating with the internal space of the tool main body portion,
The dynamic vibration absorber is attached to the tool main body portion by fitting the connection port to the connected port, and when the work tool is driven, the weight of the dynamic vibration absorber is set inside the first cylindrical portion. A work tool configured to be driven through a fluctuating pressure in the internal space of the tool main body portion introduced into at least one of the space or the internal space of the second cylindrical portion. The work tool according to any one of claims 1 to 3,
The first and second tube portions have elastic element receiving members that are movable relative to the first and second tube portions while receiving the elastic force of the elastic elements, and each elastic element The work tool is characterized in that the receiving member is fixed to the tool body through a relative movement operation with respect to the first and second cylinders.

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