JP4568600B2 - Hammer drill - Google Patents

Description

  The present invention relates to a hammer drill capable of switching between a drill mode in which only a rotating operation is performed on a tool bit and a hammer drill mode in which a rotating operation and a striking operation are performed on a tool bit.

  An electric hammer drill capable of switching between a drill mode and a hammer drill mode is disclosed in, for example, Japanese Utility Model Publication No. 5-37479 (Patent Document 1). In the electric hammer drill according to this prior art, a power transmission mechanism that constantly transmits the rotational output of the motor as a rotational force to the tool bit via the tool holder, and after converting the rotational output of the motor into a linear motion, the striking element is And a motion conversion mechanism for transmitting the tool bit as a striking force. The motion conversion mechanism has a meshing clutch in its rotation path, and when the clutch is meshed and engaged, the tool bit is driven by a rotating operation and a hammering operation (hammer drill mode), and the clutch meshing engagement is performed. In the state in which is released, the tool bit is driven only in the rotation operation (drill mode). The clutch is in meshing engagement via a mode switching change plate that moves with the tool holder when the tool holder is moved backward with respect to the main body by the pressing operation of the tool bit against the workpiece. When the pressing of the tool bit against the workpiece is released, the meshing engagement is released via the change plate moved forward together with the tool holder by the biasing force of the compression coil spring arranged on the outer periphery of the tool holder. This is a configuration.

The tool holder is formed in a cylindrical shape, and the outer peripheral portion thereof is supported by the front and rear bearings so as to be rotatable and movable in the long axis direction. In the electric hammer drill disclosed in Patent Document 1, On the other hand, the compression coil spring is arranged in series. For this reason, an arrangement space for the compression coil spring is required in the long axis direction of the tool holder, and as a result, the axial length (full length) of the hammer drill becomes long. Further, when the compression coil spring is disposed close to the outer peripheral surface of the tool holder, the compression coil spring rubs due to relative rotation with the tool holder, and as a result, there is a risk of causing problems such as wear or heat generation.
Japanese Utility Model Publication No. 5-37479

  The present invention has been made in view of such a point, and an object thereof is to provide a technique effective in reducing the size of a hammer drill.

In order to achieve the above object, the invention described in each claim is configured.
According to invention of Claim 1, the hammer drill which has a main-body part, a tool bit, a tool holder, a bearing, an operation member for mode switching, and a biasing spring is comprised. The tool bit is disposed in the tip region of the main body. The tool holder holds the tool bit in a state in which relative rotation in the circumferential direction is restricted while allowing relative movement in the long axis direction. A bearing is arrange | positioned in the outer peripheral part of the said tool holder in order to support a tool holder so that rotation with respect to a main-body part and movement to a long-axis direction are possible. The mode switching actuating member is arranged on the outer periphery of the tool holder, and the drill mode in which the tool bit only rotates together with the tool holder and the tool bit rotates together with the tool holder by the mode switching operation by the user. On the other hand, the operation is switched between a hammer drill mode in which a striking operation is performed in which the tool holder moves relative to the long axis. The biasing spring biases the mode switching actuating member to actuate either the drill mode side or the hammer drill mode side.

  According to the present invention, when the mode switching operation member is switched to the drill mode side by the mode switching operation by the user, the tool bit can be driven only by the rotation operation together with the tool holder. When the operating member is switched to the hammer drill mode side, the tool bit can be driven in the hammer drill mode in which the tool bit rotates together with the tool holder and performs a striking movement that moves relative to the tool holder in the long axis direction. The Note that, as an aspect of the “mode switching operation by the user” in the present invention, typically, a tool bit pressing operation and a pressing releasing operation with respect to the workpiece correspond to this, but the mode is arranged outside the main body. The mode switching operation member switching operation is preferably included. Further, as a mode in which the mode switching operation member is switched, when the tool holder relatively moves in the major axis direction with respect to the main body in accordance with the pressing operation and the pressing release operation of the tool bit on the workpiece, A mode in which the mode switching operation member is switched in conjunction with the movement operation of the tool holder, and when the mode switching operation member arranged outside the main body is switched, the mode switching operation member is operated by the mode switching operation. Includes any of the modes in which the switching operation is performed. The “biasing spring” typically corresponds to a compression coil spring, but preferably includes a spring other than the compression coil spring.

In the present invention, as a characteristic configuration, the main body has a cylindrical portion that supports the outer peripheral surface of the bearing. The biasing spring is arranged in parallel with the bearing outside the cylindrical portion in the radial direction of the tool holder. Furthermore, the cylindrical portion is equivalent to the reduced length of the biasing spring when the biasing spring is contracted by the tool holder being moved to the main body side together with the tool bit by pressing the tool bit against the workpiece. It is set as the structure which has the axial direction length. With such a configuration, it is not necessary to secure a space for arranging the urging spring in the long axis direction of the tool holder, and as a result, it is possible to reduce the overall length of the hammer drill and achieve compactness. When the biasing spring and the bearing are arranged in parallel, it is a matter of course that a space for arranging the biasing spring is required in the radial direction, but the radial dimension of the biasing spring is smaller than that in the major axis direction. The main body (housing) of the hammer drill tends to have an empty space in the radial direction because it accommodates an operating mechanism for driving the tool bit. For this reason, even if the biasing spring and the bearing are arranged in parallel, an increase in the radial dimension of the main body can be suppressed. In the present invention, by arranging the biasing spring outside the bearing, it becomes possible to avoid contact with the outer peripheral surface of the tool holder, and the problem of wear or heat generation due to contact with the outer peripheral surface can be solved. Can do.
In addition, the configuration in which the urging spring is arranged outside the cylindrical portion makes it possible to rationally arrange the bearing and the urging spring, and the cylindrical portion is provided when the urging spring is contracted. Since the length in the major axis direction is equal to the reduced length of the biasing spring, the operation of the biasing spring can be stabilized.

(Invention of Claim 2)
According to the second aspect of the present invention, the hammer drill according to the first aspect of the present invention is long on the inner peripheral surface of the tool holder when the front end region side of the tool body is defined as the front portion and the opposite side is defined as the rear portion. A stop ring is provided for receiving a rear portion in the longitudinal direction of the meson that is slidably disposed in the axial direction. The stop ring is configured such that movement in the major axis direction is restricted by a spring ring and a seal ring disposed on the inner peripheral surface of the tool holder. Further, the seal ring includes a sealing protrusion that abuts on the inner peripheral surface of the tool holder, a sealing protrusion that abuts on the outer peripheral surface of the intermediate element, a rattling prevention protrusion that abuts on a step portion on the inner peripheral surface of the tool holder, and a stop. And a projection for preventing rattling that abuts against the front surface of the ring.

  According to the present invention, a technique effective for achieving a compact hammer drill is provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3 show the configuration of an electric hammer drill 101 (hereinafter simply referred to as hammer drill 101) according to the present embodiment. FIG. 4 shows an A portion of FIG. 1 as an enlarged view, and FIG. 5 shows a cross-sectional structure of the seal ring 163. 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 tip region (front end side) of the main body 103. A drill bit 119 that is detachably attached via a hammer chuck 135 and a hand grip (not shown) disposed on the rear end side of the main body 103 opposite to the drill bit 119 are mainly configured. The drill bit 119 is held with respect to the hammer chuck 135 in a state where relative sliding in the major axis direction is possible and relative rotation in the circumferential direction is restricted. The drill bit 119 corresponds to a “tool bit” in the present invention. In the following description, for convenience of explanation, the drill bit 119 side is referred to as the front side, and the hand grip side is referred to as the rear side.

  The main body 103 includes a motor housing 105 that houses a drive motor 111 (the tip portion is shown in FIGS. 1 to 3), and a gear housing 107 that houses a power transmission mechanism 113, a motion conversion mechanism 115, and a striking element 117. It is configured. The drive motor 111 is disposed such that the motor shaft 111a is parallel to the long axis direction of the main body 103 (that is, the long axis direction of the drill bit 119). The rotational output of the drive motor 111 is transmitted to the tool holder guide 131 after being appropriately decelerated by the power transmission mechanism 113, and the drill bit 119 rotates in the circumferential direction together with the hammer chuck 135 attached to the tip of the tool holder guide 131. Be operated. The above-mentioned tool holder guide 131 and hammer chuck 135 constitute a “tool holder” in the present invention. The rotation output of the drive motor 111 is appropriately converted into a linear motion by the motion converting mechanism 115 and then transmitted to the striking element 117 and acts as an impact force in the major axis direction on the drill bit 119 via the striking element 117. To do.

  In FIG. 4, the power transmission mechanism 113, the motion conversion mechanism 115, and the striking element 117 are shown enlarged. The power transmission mechanism 113 includes a driven gear 122 (see FIGS. 1 to 3) that meshes with and engages with a pinion 121 provided on the motor shaft 111 a of the drive motor 111, and an intermediate shaft that rotates in the vertical plane together with the driven gear 122. 123, a first transmission gear 124 that is rotationally driven together with the intermediate shaft 123, and a second transmission gear 125 that meshes and engages with the first transmission gear 124. The second transmission gear 125 is attached to the outer periphery of the tool holder guide 131 via a torque limiter 126. When the circumferential load acting on the drill bit 119 exceeds a set torque value, the second transmission gear 125 rotates to the tool holder guide 131. Cut off power transmission. The intermediate shaft 123 is disposed in parallel with the long axis direction of the drill bit 119. The tool holder guide 131 is formed in a cylindrical shape, and an outer peripheral portion of the tool holder guide 131 is rotatably supported in a vertical plane via front and rear bearings 127 and 128 and is supported so as to be movable in the axial direction. The chuck mounting portion 133 is integrally connected to the distal end side of the sleeve 132.

The motion conversion mechanism 115 is mainly composed of an intermediate shaft 123, a clutch cam 141, a rotating body 142, a swash plate 143, and a cylinder 147. The clutch cam 141 is attached to the intermediate shaft 123 via a spline so as to rotate together with the intermediate shaft 123 and to move relative to the axial direction. The rotating body 142 is mounted so as to be rotatable relative to the intermediate shaft 123 in a state where movement in the axial direction is restricted. The clutch cam 141 and the rotating body 142 are arranged in an opposing manner, and have clutch teeth 141a and 142a on the opposing surfaces. Then, on the intermediate shaft 123, the clutch cam 141 is moved in a direction approaching the rotating body 142, whereby the clutch teeth 141a of the clutch cam 141 are engaged with the clutch teeth 142a of the rotating body 142, and the clutch cam 141 rotates. The meshing engagement is released by moving in a direction away from the body 142.
The swash plate 143 is attached to the inclined outer peripheral surface of the rotating body 142 via a bearing 144 so as to be relatively rotatable, and is swung in the major axis direction of the drill bit 119 as the rotating body 142 rotates. The movement causes the cylinder 147 to reciprocate linearly in the cylindrical hole of the sleeve 132 in the tool holder guide 131. Note that the swash plate 143 and the cylinder 147 are joined to the swing rod 145 protruding from the swash plate 143 by engaging the engaging member 148 provided at the rear end of the cylinder 147 in a loose fit. .

  The striking element 117 is slidably disposed in the cylindrical hole of the chuck mounting portion 133 of the tool holder guide 131 and the striker 151 as a striking element slidably disposed on the bore inner wall of the cylinder 147. An impact bolt 152 as a meson that transmits 151 kinetic energy to the drill bit 119 is mainly configured. An air chamber 153 defined by a radial wall surface of the cylinder 147 and the striker 151 is formed in the cylinder 147, and the striker 151 includes an air chamber 153 that accompanies the reciprocating linear motion of the cylinder 147 in the sleeve 132. It is driven linearly through pressure fluctuations inside, that is, through an air spring. The striker 151 transmits the kinetic energy to the drill bit 119 by colliding with the impact bolt 152.

  In the motion conversion mechanism 115, the meshing engagement operation and the releasing operation of the clutch teeth 141a of the clutch cam 141 and the clutch teeth 142a of the rotating body 142 are performed via a change plate 155 that moves in the longitudinal direction together with the tool holder guide 131. It is set to be performed. The change plate 155 corresponds to the “mode switching operation member” in the present invention. The change plate 155 is disposed so as to straddle the sleeve 132 of the tool holder guide 131 and the intermediate shaft 123, and can be relatively rotated with respect to the outer peripheral portion of the sleeve 132 and can be relatively moved in the axial direction. The clutch cam 141 is engaged with the outer periphery of the clutch cam 141 so as to be rotatable relative to the outer periphery of the clutch cam 141 and in a state where movement in the axial direction is restricted. The change plate 155 is normally pressed forward by the urging force of the compression coil spring 157 and is held at a position regulated by a flange-like stopper plate 132 a provided on the outer periphery of the sleeve 132.

  The compression coil spring 157 is arranged in parallel with the bearing 128 in the outer peripheral region of the rear bearing 128 that supports the rear outer peripheral portion of the sleeve 132 in the tool holder guide 131. That is, the gear housing 107 is formed with a bearing holding cylindrical portion 158 fitted to the outer periphery of the bearing 128, and a compression coil spring 157 is disposed on the outer peripheral side of the cylindrical portion 158. The compression coil spring 157 is interposed such that one end in the axial direction is in contact with a vertical wall surface connected to the cylindrical portion 158 of the gear housing 107 and the other end is in contact with the change plate 155 via a washer plate 156.

  The urging force of the compression coil spring 157 acts as a force for moving the tool holder guide 131 together with the change plate 155. Therefore, in a state where the drill bit 119 is not pressed against the workpiece, that is, in an unloaded state where the pressing force is not applied to the tool holder guide 131, the change plate 155 is moved forward by the urging force of the compression coil spring 157. The clutch cam 141 is moved to move away from the rotating body 142, and the meshing engagement between the clutch teeth 141a of the clutch cam 141 and the clutch teeth 142a of the rotating body 142 is released (see FIGS. 1 and 2). On the other hand, the change plate 155 resists the compression coil spring 157 together with the tool holder guide 131 when the drill bit 119 is pressed against the workpiece and the tool holder guide 131 is moved backward relative to the main body 103. Then, it moves rearward and moves the clutch cam 141 toward the side close to the rotating body 142. As a result, the clutch teeth 141a of the clutch cam 141 are engaged with and engaged with the clutch teeth 142a of the rotating body 142 (see FIG. 3).

  A mode change lever 159 as a mode switching operation member that can be rotated by the user is disposed outside the gear housing 107 as indicated by a two-dot chain line in FIGS. The mode change lever 159 has a rotation center P in a direction orthogonal to the long axis direction of the tool holder guide 131 and protrudes inward of the gear housing 107 at an eccentric position spaced from the rotation center P by a predetermined distance. And a stop pin 159a disposed on the rear surface side of the change plate 155. When the mode change lever 159 is switched to the drill mode side, the stop pin 159a comes into contact with the rear surface of the change plate 155 (washer plate 156) to move the change plate 155 backward as shown in FIG. When it is restricted and the mode change lever 159 is switched to the hammer drill mode side, as shown in FIGS. 2 and 3, the change plate 155 is allowed to move backward as shown in FIGS.

  A stop ring 161 for receiving the rear portion of the impact bolt 152 is disposed on the inner peripheral surface of the tool holder guide 131, and a gap between the impact bolt 152 and the tool holder guide 131 is sealed on the front side of the stop ring 161. A seal ring 163 is disposed. The stop ring 161 includes a spring ring 165 disposed on the inner peripheral surface of the sleeve 132 of the sleeve 132 in the tool holder guide 131 and a seal ring 163 disposed on the inner peripheral surface of the chuck mounting portion 133 of the tool holder guide 131. Therefore, the back-and-forth movement can be suppressed. In the present embodiment, as shown in an enlarged view in FIG. 5, the sealing function and prevention of rattling of the stop ring 161 are combined by changing the cross-sectional shape of the generally known X ring for sealing. Yes. That is, the dust-proof seal ring 163 has two seal protrusions 163a arranged in the axial direction on each of the inner peripheral side and the outer peripheral side, and one ratchet prevention protrusion 163b on each end face in the axial direction. It is set as the structure which has. As a result, the seal ring 163 has a backlash prevention function in addition to the seal function. One of the seal protrusions 163a contacts the inner peripheral surface of the cylindrical hole of the tool holder guide 131 and the other contacts the outer peripheral surface of the impact bolt 152. One of the backlash prevention protrusions 163b is a step of the chuck mounting portion 133. The other is in contact with the front surface of the stop ring 161.

  The hammer drill 101 according to the present embodiment is configured as described above. Next, the operation and usage method of the hammer drill 101 will be described. In the unloaded state where the drill bit 119 is not pressed against the workpiece, the change plate 155 is pushed forward together with the tool holder guide 131 by the urging force of the compression coil spring 157 as shown in FIGS. The clutch teeth 141 a of 141 are separated from the clutch teeth 142 a of the rotating body 142. In this state, as shown in FIG. 1, when the mode change lever 159 is switched to the drill mode side, the stop pin 159a is displaced forward and comes into contact with the rear surface of the change plate 155. The rearward movement of the holder guide 131 is restricted.

  In this state, when the drive motor 111 is energized and driven, the rotational output of the drive motor 111 is transmitted as a rotational force to the tool holder guide 131 via the power transmission mechanism 113, and the hammer chuck 135 attached to the tool holder 131 is used. At the same time, the drill bit 119 is rotated. On the other hand, on the motion conversion mechanism 115 side, the clutch teeth 141a of the clutch cam 141 are separated from the clutch teeth 142a of the rotator 142, so the rotator 142 is not rotated. That is, in the state switched to the drill mode, the drill bit 119 is driven only by the rotation operation. The operator can perform the drilling operation by appropriately pressing the drill bit 119 against the workpiece. At this time, although a pushing force is applied to the tool holder guide 131 by the pushing operation of the drill bit 119, the backward movement is restricted by the stop pin 159a of the mode change lever 159 as described above. Stable work at is realized.

  On the other hand, when the mode change lever 159 is switched to the hammer drill mode side, as shown in FIG. 2, the stop pin 159a of the mode change lever 159 is displaced rearward and the movement restriction of the change plate 155 is released. When the drill bit 119 is pressed against the workpiece in this state, as shown in FIG. 3, the hammer chuck 135, the tool holder 131, and the change plate 155 together with the drill bit 119 compress the compression coil spring 157 against the main body 103. It moves backwards relative to it. As a result, the change plate 155 moves the clutch cam 141 toward the rotating body 142, and the clutch teeth 141 a of the clutch cam 141 are engaged with and engaged with the clutch teeth 142 a of the rotating body 142. Therefore, the rotational force is transmitted to the rotating body 142 side, and the cylinder 147 moves linearly in the tool holder guide 131 through the swinging motion of the swash plate 143. As the cylinder 147 moves linearly, the striker 151 constituting the striking element 117 is moved via the air spring, and further, the linear movement is transmitted to the drill bit 119 via the impact bolt 152. That is, in the hammer drill mode, the drill bit 119 is driven by a rotating operation and a striking operation, so that a drilling operation can be performed on the workpiece.

  In the present embodiment, the compression coil spring 157 arranged to urge the tool holder guide 131 together with the mode change change plate 155 is disposed on the rear side of the tool holder guide 131 in the radial direction of the tool holder guide 131. The bearings 128 are arranged in parallel to the outside in the radial direction of the bearings 128 to be supported. By adopting such a configuration, it is not necessary to secure a space for arranging the compression coil spring 157 in the long axis direction of the tool holder guide 131. As a result, the overall length of the hammer drill 101 can be shortened to achieve compactness. Further, since the compression coil spring 157 is disposed outside the bearing 128, it is possible to avoid contact with the outer peripheral surface of the tool holder guide 131. As a result, the problem of wear or heat generation due to contact with the outer peripheral surface can be solved.

  Further, in the present embodiment, the dust-proof seal ring 163 has two seal protrusions 163a arranged in the axial direction on each of the inner peripheral side and the outer peripheral side, and one end face in the axial direction has one With the configuration having the rattling prevention protrusion 163b, the sealing function and the rattling prevention of the stop ring 161 can be combined. Since the seal ring 163 also serves to prevent rattling of the stop ring 161, the space can be reduced, and the number of parts can be reduced to reduce the cost.

Although the present embodiment has been described in the case of an arrangement configuration in which the long axis of the drive holder 111 is parallel to the long axis of the tool holder guide 131, the drive motor 111 has a long axis of the tool holder guide 131. You may apply to the electric hammer drill 101 which employ | adopted the crank mechanism as the electric hammer drill 101 of the arrangement configuration which a long-axis cross | intersect, ie, the motion conversion mechanism 115 which converts the rotational output of the drive motor 111 into a linear motion.
In this embodiment, the mode switching change plate 155 moves with the tool holder guide 131 to engage and disengage the clutch cam 141. However, the tool holder guide 131 moves. Regardless of whether or not the mode change lever 159 is switched, the clutch cam 141 may be engaged and released. In that case, the urging direction of the compression coil spring 157 may be either the direction in which the clutch cam 141 is engaged or engaged, or the direction in which the engagement is released.

It is sectional drawing which shows the electric hammer drill which concerns on this Embodiment, and shows the time of drill mode. It is sectional drawing which shows the electric hammer drill which concerns on this Embodiment, and shows the time of no load at the time of hammer drill mode. It is sectional drawing which shows the electric hammer drill which concerns on this Embodiment, and shows the time of a load at the time of hammer drill mode. It is an enlarged view of the A section of FIG. It is sectional drawing of a seal ring.

101 Electric hammer drill (hammer drill)
103 Body 105 Motor housing 107 Gear housing 111 Drive motor 111
111a Motor shaft 113 Power transmission mechanism 115 Motion conversion mechanism 117 Impact element 119 Drill bit (tool bit)
121 pinion 122 driven gear 123 intermediate shaft 124 first transmission gear 125 second transmission gear 126 torque limiter 127 bearing 128 bearing 131 tool holder guide (tool holder)
132 Sleeve 132a Stopper plate 133 Chuck mounting part 135 Hammer chuck (tool holder)
141 Clutch cam 141a Clutch tooth 142 Rotating body 142a Clutch tooth 143 Swash plate 144 Bearing 145 Swing rod 147 Cylinder 148 Engaging member 151 Striker 152 Impact bolt 153 Air chamber 155 Change plate (Mode switching operation member)
156 Washer plate 157 Compression coil spring (biasing spring)
158 Cylindrical portion 159 Mode change lever 159a Stop pin 161 Stop ring 163 Seal ring 163a Seal projection 163b Anti-rattle projection 165 Spring ring

Claims (2)

The main body,
A tool bit arranged in a tip region of the main body,
A tool holder for holding the tool bit in a state in which relative rotation in the circumferential direction is restricted while allowing relative movement in the long axis direction;
A bearing disposed on the outer periphery of the tool holder to support the tool holder so as to be rotatable with respect to the main body and movable in the long axis direction;
Drill mode in which the tool bit is rotated only together with the tool holder by a mode switching operation by a user, and the tool bit is rotated while rotating together with the tool holder. A mode switching operation member that is switched between a hammer drill mode that performs a striking motion that moves relative to the holder in the long axis direction;
A hammer drill that biases the mode switching actuating member to actuate either the drill mode side or the hammer drill mode side;
The main body portion includes a cylindrical portion that supports an outer peripheral surface of the bearing, and the biasing spring is disposed in parallel with the bearing on the outer side of the cylindrical portion in the radial direction of the tool holder, and The cylindrical portion has a length equivalent to a reduced length of the biasing spring when the tool holder is moved toward the main body by pressing the tool bit against the workpiece, and the biasing spring is reduced. A hammer drill characterized by having an axial length. The hammer drill according to claim 1,
When the front end region side of the tool body is defined as the front portion and the opposite side is defined as the rear portion , the rear portion in the long axis direction of the meson that is slidably disposed in the long axis direction on the inner peripheral surface of the cylindrical hole of the tool holder The stop ring is configured to be sandwiched between a spring ring and a seal ring disposed on the inner peripheral surface of the tool holder, and the movement in the long axis direction is restricted. The seal ring includes a sealing projection that abuts on the inner peripheral surface of the tool holder, a sealing projection that abuts on the outer peripheral surface of the intermediate element, and a rattling-preventing projection that abuts on a step portion on the inner peripheral surface of the tool holder. A hammer drill having a backlash preventing projection that abuts against the end surface in the major axis direction of the stop ring.

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