JP4106709B2 - Vibration drill - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration drill used for drilling, for example, concrete, mortar, tile, and the like, and more particularly, a drill mode in which drilling is performed by rotating the drill bit, and drilling by rotating and vibrating the drill bit. The present invention relates to a vibration drill having a vibration drill mode for performing.
[0002]
[Prior art]
[Patent Document 1]
Utility Model Application Publication No. 59-69808
[Patent Document 2]
JP-A-8-323520
A conventional example of this type of vibration drill is shown in FIG. In the figure, reference numeral 1 denotes a main body frame portion that forms the outline of the vibration drill and arranges built-in components at predetermined positions, and includes a gear cover 17, an inner cover 18, an outer cover 19, a housing 7, and a handle portion 6. Reference numeral 2 denotes a spindle inserted laterally in the gear cover 17, and 3 denotes a drill chuck attached to the tip of the spindle. A rotating ratchet 4 is attached near the center of the spindle 2. The rotating ratchet 4 rotates with the rotation of the spindle 2 and moves with the axial movement of the spindle 2. In addition, serrated irregularities are formed on one surface 4 a of the rotating ratchet 4.
[0003]
Reference numeral 5 denotes a fixed ratchet disposed at a position facing the rotating ratchet 4, and serrated irregularities are similarly formed on one surface 5 a thereof. The fixed ratchet 5 has a hollow cylindrical shape and is fixed regardless of the rotation of the spindle 2 and the movement in the axial direction.
[0004]
On the other hand, a motor 8 is disposed inside a housing 7 connected to the handle portion 6. The rotational driving force of the motor 8 is transmitted to the gear 10 through the rotating shaft 9. Since the gear 10 is press-fitted into the second pinion 11, the rotational driving force is transmitted to the second pinion 11. The second pinion 11 has two pinion portions 11a and 11b having different numbers of teeth, which are engaged with the low speed gear 12 and the high speed gear 13, respectively, and when the second pinion 11 rotates, both the gears 12 and 13 also rotate. .
[0005]
A clutch disk 14 is engaged with the spindle 2 and is slidable in the axial direction. When the clutch disk 14 is inserted into the recess of the low speed gear 12 as shown in FIG. 1, the rotation of the second pinion 11 is transmitted to the spindle 2 via the low speed gear 12 and the clutch disk 14. On the other hand, when the clutch disk 14 slides to the right from the position of FIG. 1 and is inserted into the recess of the high speed gear 13, the rotation of the second pinion 11 is transmitted to the spindle 2 via the high speed gear 13 and the clutch disk 14. Is done. Accordingly, the spindle 2 can be rotated at a low speed or at a high speed by the movement of the clutch disk 14.
[0006]
Reference numeral 15 denotes a change lever for switching the operation mode of the vibration drill, that is, switching between the drill mode and the vibration drill mode. A change shaft 16 is press-fitted into the change lever 15, and when the change lever 15 is rotated, the change shaft 16 is also rotated together. As shown in FIGS. 2, 3 and 4, the change shaft 16 has a notch 16a. When the notch 16a is in the position shown in FIG. 2, the impact drill operates in the drill mode, and the notch 16a is shown in FIG. When in position, it operates as a vibration drill mode.
[0007]
(A) Drill mode
Now, when a bit (not shown) attached to the drill chuck 3 is brought into contact with the surface to be processed and the handle portion 6 is pushed in the direction of the arrow in FIG. 1, the notch portion 16a of the change shaft 16 is brought to the position in FIG. If so, the end of the spindle 2 abuts against the change shaft 16 and cannot move to the right. Therefore, the uneven surface 4 a of the rotating ratchet 4 and the uneven surface 5 a of the fixed ratchet 5 are not in contact with each other. Therefore, the rotational driving force of the motor 8 is transmitted to the spindle via the low speed gear 12 or the high speed gear 13, and the bit is given a rotational force.
[0008]
(B) Vibration drill mode
On the other hand, in the case of the vibration drill mode, the change lever 15 is rotated to bring the cutout portion 16a of the change shaft 16 to the position shown in FIG. Then, when the bit mounted on the drill chuck 3 is brought into contact with the work surface and the handle portion 6 is pushed in the direction of the arrow in FIG. 1, the end of the spindle 2 enters the notch 16a as shown in FIG. That is, since the spindle 2 moves slightly in the right direction, the uneven surface 4 a of the rotating ratchet 4 comes into contact with the uneven surface of the fixed ratchet 5.
[0009]
4, when the spindle 2 is rotated in the state shown in FIG. 4, the rotating ratchet 4 is engaged with the fixed ratchet 5 to rotate, so that vibration is generated by the uneven surfaces of both the ratchets 4 and 5. This vibration is transmitted to the bit (not shown) through the spindle 2. That is, a rotational force and a vibration are applied to the bit, and a drilling operation is performed by both.
[0010]
However, in the vibration drill as described above, when operating in the vibration drill mode, not only the vibration generated by the rotation of the concave and convex surfaces of the ratchets 4 and 5 is transmitted to the bit, but also the fixed ratchet 5 and the inner It is also transmitted from the housing 7 to the handle portion 6 through the cover 18. For this reason, a big vibration is transmitted to the user of a vibration drill, and there exists a problem of producing discomfort. In particular, when using a vibration drill continuously for a long time, care must be taken so that vibration transmitted to the user does not affect the health of the user.
[0011]
Several proposals have been made on structures for reducing vibration transmitted to the user. For example, Patent Document 1 discloses a structure in which a clutch cam 21 is supported so as to be movable in the axial direction of a spindle 20 as shown in FIG.
[0012]
In the figure, reference numeral 21 denotes a rotating cam that rotates together with the spindle 20. The cam surface 21a of the rotary cam 21 is formed with serrated irregularities.
[0013]
On the other hand, the clutch cam 22 includes a hollow cylindrical portion slidable in the axial direction with respect to the spindle 20 and a flange portion 22b. A serrated irregular surface is formed on the cam surface 22c of the flange portion 22b. A restricting groove 22a is provided in the vicinity of the rear end portion of the clutch cam 22. A plate 24 extending in the vertical direction is engaged with the restriction groove 22a. A spring 23 is provided between the flange 22 b of the clutch cam 22 and the plate 24.
[0014]
The spring 23 always urges the clutch cam 22 toward the rotating cam 21, and the cam surfaces 21 a and 22 c are pressed against each other when the spindle 20 is retracted. When the pressing force applied to the spindle 20 overcomes the elastic force of the spring 23, the spring 23 is compressed and the clutch cam 22 moves backward (moves in the right direction in the figure). However, since the restriction groove 22a is provided, the clutch cam 22 can move only within the lateral width of the groove. When the clutch cam 22 moves forward from the retracted position by the spring force of the spring 23, it collides with the rotating cam 21, and the rotating cam 21 vibrates together with the spindle 20.
[0015]
According to such a structure, the vibration generated by the contact between the cam surfaces 21a and 22c is alleviated by the spring 23 and transmitted to the handle portion (not shown), so that the ratchet 5 is fixedly arranged as shown in FIG. Thus, there is an effect that vibration transmitted to the user is reduced.
[0016]
However, since the clutch cam 22 repeatedly advances and retreats in the range of the lateral width of the groove 22 a engaged with the plate 24, the rear end portion 22 d of the clutch cam 22 repeatedly collides with the plate 24.
[0017]
Therefore, it is unavoidable that vibration generated in this portion is still transmitted to the handle portion, and the rear end portion 22d or the plate 24 is easily broken due to mechanical fatigue. Further, there is a product using the same technology as that of Patent Document 1, but avoiding the transmission of vibration to the handle part by causing the spindle or clutch cam to collide rearward only by giving a slight pressing force during drilling work. I couldn't.
[0018]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a vibration drill that solves the above-mentioned conventional problems.
[0019]
Specifically, an object of the present invention is to provide a vibration drill that can reduce vibration transmitted to the user without impairing the drilling ability.
[0020]
Another object of the present invention is to provide a vibration drill that generates a large vibration in a bit attached to a drill chuck and transmits a relatively small vibration to a handle portion.
[0021]
Another object of the present invention is to provide a first ratchet that rotates together with the spindle and a second ratchet that moves in the axial direction of the spindle, and a component that vibrates by supporting the second ratchet with a spring collides with the main body frame. It is to provide a vibration drill in which the members constituting the ratchet are less likely to cause mechanical fatigue by adopting a structure that does not (hereinafter referred to as a floating structure).
[0022]
[Means for Solving the Problems]
  In order to achieve the above object, the present inventionA body frame part that forms an outline of the vibration drill, and the built-in components are arranged at predetermined positions; a motor that is housed in the body frame part; a spindle that is rotated by the motor and is movable in the axial direction; A first ratchet fixed to the spindle and capable of rotating and moving in the axial direction together with the spindle, and having a concave and convex portion surface, and a concave and convex portion surface facing the concave and convex portion surface of the first ratchet. A second ratchet provided so as to slide on the spindle in the axial direction, and urging the second ratchet in the first ratchet direction, and the first ratchet with respect to the second ratchet In a vibration drill that brings the concave and convex surfaces into contact with and apart from each other by relative rotation, and applies axial vibration to the spindle, the spindle extends from the main body frame portion in the spindle direction. A first spring for urging the second ratchet in the first ratchet direction is provided between the side wall portion and the second ratchet, and between the body frame portion and the second ratchet, A second spring for urging the second ratchet in a direction opposite to the urging force of the first spring is provided, and when a pressing force is not applied to the main body frame portion and a light pressing force is applied to the main body frame portion, One characteristic is that the first ratchet and the second ratchet are in contact with the main body frame portion in a state where the first ratchet and the second ratchet are in contact with each other, and maintain a floating state with respect to the main body frame portion.
[0025]
  Another feature of the present invention is that the main body frame is 15 to 25 kg.fWhen the pressing force is applied, the second ratchet and the second spring are disengaged from each other, and the second ratchet is biased only from the first spring.
[0026]
Another feature of the present invention is that f / fc is 2 or more, more preferably 3 or more, where f is the vibration frequency of the second ratchet and fc is the natural frequency determined by the spring constant of the vibration drill body and the first spring. It is in that.
Other features and advantages of the present invention will be more clearly understood from the following description.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described in detail below.
(First embodiment)
FIG. 6 is a block diagram of the main part showing the first embodiment of the vibration drill of the present invention.
As shown in the figure, a spindle 102 is provided in a main body frame 101 so as to be able to move forward (move leftward in the figure) and move backward (move rightward in the figure) relative to the work material 119. A chuck 103 for mounting a bit 118 is provided at the tip of the spindle 102. A first ratchet 104 and a second ratchet 105 are provided at substantially the center of the main body frame 101. The first ratchet 104 rotates and moves in the axial direction together with the spindle 102 and has serrated irregularities on one surface. The second ratchet 105 has a double cylindrical shape, and the inner cylindrical portion 105 a slides on the spindle 102. The outer cylindrical portion 105b slides in the axial direction of the spindle 102 along the inner wall of the main body frame portion 101, but has a cutout portion at a part of the circumferential surface so as not to rotate. Cam surfaces are formed on the inner cylindrical portion 105a and the bottom portion 105c of the outer cylindrical portion 105b, and serrated irregularities are formed. A side wall 122 extends from the main body frame 101 toward the inner spindle, and a spring 120 is provided between the side wall 122 and the cylindrical bottom 105c. In the present embodiment, the spring constant of the spring 120 is appropriately selected so that the end portion 105d of the second ratchet 105 does not contact the side wall portion 122 when the bit 118 is pressed against the work material 119. There is a special feature.
[0028]
Usually, when a human uses a vibration drill, the pressing force to the main body frame 101 when the bit 118 is pressed against the work material 119 is measured, and although there is variation depending on the person, it may be in the range of 15 to 25 kgf. It was found. Therefore, in this embodiment, the spring 120 having a spring constant is used so that the rear end portion 105d of the second ratchet 105 does not contact the side wall member 122 when a pressing force of 15 to 25 kgf is applied to the main body frame portion 101. That is, when the pressing force is in the range of 15 to 25 kgf, the second ratchet 105, which is a striking force generating portion, is structured to float from the housing by the spring 120, so that vibration transmitted to the user is reduced as will be described later.
[0029]
  That is, FIG. 6 shows the case where the force for pressing the main body frame portion 101 is zero, and the first ratchet 104 and the second ratchet 105 are separated from each other, but when a small pressing force is generated, the first ratchet 104 is generated as shown in FIG. The ratchet 104 and the second ratchet 105 come into contact with each other, and a larger pressing force (15 to 25 kg)f) Occurs, the spring 120 is compressed as shown in FIG. However, even if a large pressing force is generated, the second ratchet 105 maintains a floating state as shown in FIG.
[0030]
  In addition, although it demonstrated on the premise of the state at the time of a stop here, pressing force is 15-25 kg also at the time of a drilling operation | work.fIt has been confirmed by experiments that the vibration transmitted to the hand is small in the range up to. Further, as can be seen from FIG. 8, the spindle 102 does not come into contact with the main body frame portion 101.
[0031]
Returning to the description of FIG. 6, reference numeral 109 denotes a rotating shaft to which a rotational driving force is transmitted by a motor (not shown), and the rotational driving force is transmitted to the second pinion 111 via the gear 110. Reference numeral 112 denotes a low-speed gear, 113 denotes a high-speed gear, and 114 denotes a clutch disk. When the clutch disk 114 is in the position shown in the drawing, the rotational force is transmitted to the spindle 102 via the low-speed gear.
[0032]
On the other hand, when the change lever 117 is rotated to rotate the clutch disk 114 to a position where the high speed gear and the spindle 102 are engaged, the rotational force of the second pinion 111 is transmitted to the spindle 102 via the high speed gear 113. Therefore, the spindle 102 can be rotated at a low speed or can be rotated at a high speed according to the rotation position of the change lever 117.
[0033]
Next, the reason why the vibration transmitted to the user by the structure of the above embodiment, that is, the vibration of the vibration drill main body is reduced will be described.
[0034]
If the structure of FIG. 6 is considered as a model in which the second ratchet 105 is connected to one end of the spring 120 and the vibration drill body M other than the second ratchet is connected to the other end, it is represented as a simple model as shown in FIG. be able to. When the displacement due to the vibration of the second ratchet 105 is Zr, and the displacement due to the vibration of the main body due to this displacement is Zb, the vibration transmissibility T is
T = | Zb / Zr | (1)
It is represented by
[0035]
Further, if the vibration frequency of the second ratchet 105 is f and the natural frequency determined from the drill body M and the spring constant is fc, T is expressed by the following equation.
T = | Zb / Zr | = 1 / | 1- (f / fc)²| (2)
However, the vibration frequency of the second ratchet 105 is represented by N × A, where N is the number of rotations of the first ratchet 104 and A is the number of sawtooth-shaped convex portions of the first and second ratchets. For example, if N = 36.7 rps and A = 13, f will be about 480 HZ.
The equation (2) indicates that the vibration of the second ratchet 105 is less likely to be transmitted to the drill body M as the ratio of the vibration frequency f of the second ratchet 105 to the natural frequency of the drill body M is greater than 1.
[0036]
FIG. 10 shows a logarithmic graph of the expression (2). When f / fc = 1, T is infinite and it is a dangerous region that causes resonance. However, if f / fc = √2 from equation (2), T = 1, and f / fc = √ It can be seen that the vibration transmissibility T becomes smaller as the value becomes larger than 2. From experiments, it has been found that if the vibration transmissibility T is about 0.5 or less, the effect of vibration reduction is sufficiently recognized. To satisfy this condition, f / fc needs to be larger than about 2. Further, if f / fc is larger than 3, T becomes about 0.1 and the effect becomes more remarkable.
[0037]
In the embodiment of FIG. 6, when the bit 118 does not contact the work material 119, that is, when the pressing force is zero, the spindle 102 is moved forward (left of the figure) by the spring 123 provided between the spindle 102 and the bearing 124. The first ratchet 104 also moves forward. At this time, a locking member 125 is provided in front of the second ratchet 105, and the second ratchet 105 comes into contact with the locking member 125 and stops. On the other hand, the spindle 102 and the first ratchet 104 are further advanced by the force of the spring 123 and move to a position where the ratchets are not engaged with each other. When the pressing force is 0, only the rotation is transmitted without generating vibration. The locking member 125 is thick and has no stress concentration, and does not break due to mechanical fatigue due to collision with the first ratchet 104 as in the prior art. However, in such a configuration, when the pressing force is relatively small, it is inevitable that the second ratchet 105 and the locking member 125 collide and the vibration is transmitted to the main body frame 101. In order to solve this problem, it can be considered that the locking member 125 is made of an elastic body such as rubber. This is because vibration transmission can be reduced by the elastic force and damping effect of rubber.
(Second embodiment)
FIGS. 11 to 14 show another embodiment of the present invention which solves the above-described problem. The second spring 121 biases the second ratchet 105 in the opposite direction to the biasing force of the first spring 120. Is provided.
[0038]
In the figure, the same components as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0039]
When the pressing force applied to the main body frame 101 is zero (FIG. 11), the spindle 102 is moved forward by the spring 123, and therefore the first ratchet 104 is also moved forward. The second ratchet 105 moves forward to a position where the forces of the first spring 120 and the second spring 121 are balanced. Therefore, the first ratchet 104 and the second ratchet 105 can be separated from each other by appropriately selecting the spring constants of the springs 120 and 121.
[0040]
When the main body frame 101 is lightly pressed, an extremely light pressing force acts on the spindle 102, and the first ratchet 104 and the second ratchet 105 are lightly engaged as shown in FIG. In this case, the washer 128 attached to the end of the second spring 121 is separated from the abutting portion 101a of the housing, and the second ratchet 105 is completely lifted from the vibration drill body. Therefore, the vibration transmitted to the user is small because the vibration of the second ratchet 105 is difficult to be transmitted to the housing 101. Further, since the fluctuation of the housing 101 is small, the drilling position of the work material 119 is easily determined.
[0041]
When the main body frame 101 is pressed a little harder, the washer 128 and the abutting portion 101a of the housing come into contact with each other as shown in FIG. However, with respect to the impact applied to the main body frame 101, the weight of the parts of the washer 128 is very light compared to the collision by the second ratchet 105, and the pressing force of the second spring is an internal force of the main body frame 101, and Since it does not become the force which moves the part 101, it is a level which does not become a problem, and this has also been confirmed by experiment.
[0042]
On the other hand, when the main body frame 101 is strongly pressed, the spindle 102 and the first ratchet 104 move rearward (rightward in the drawing), and a washer 128 provided on the second spring 121 comes into contact with the portion 101a. As shown in FIG. 14, when the first ratchet 104 further moves rearward from this state, it moves rearward together while engaging with the second ratchet 105. However, the spring constant of the first spring 120 is selected so that a gap is formed between the second ratchet 105 and the side wall 122 at 15 to 25 kgf which is a normal human pressing force as in the first embodiment. Therefore, the second ratchet 105 is in a floating state. Therefore, the vibration of the second ratchet 105 is not easily transmitted to the main body frame portion 101, and does not give the user unpleasant feeling.
[0043]
In the above embodiment, when the pressing force is 0, the second ratchet 105 is set to be held at a position where the forces of the first spring 120 and the second spring 121 are balanced, as shown in FIG. B) It may be set so that the washer 128 is held in contact with the abutting portion 101a. In this way, the stationary position of the second ratchet 105 can be accurately determined. Even if it does in this way, the influence which it has on a vibration is a level which does not become a problem as mentioned above.
(Third embodiment)
FIG. 16 shows another embodiment of the vibration drill according to the present invention. The same components as those in FIGS. 6 and 11 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0044]
In this embodiment, there is a recess at the center of the main body frame 101, and a hole is formed at the bottom. On the other hand, a concave portion is also formed in the outer cylindrical portion 105b of the second ratchet 105, and the change ball 129 can be inserted into and removed from the concave portion of the outer cylindrical portion 105b through the hole of the main body frame portion 101 described above. A change lever 126 with a magnet is provided above the change ball 129.
[0045]
Now, when the magnet of the change lever 126 is excited and the change ball 129 is attracted, the change ball 129 is detached from the concave portion of the outer cylindrical portion 105b of the second ratchet 105, and the state shown in FIG.
[0046]
Therefore, when the spindle 102 rotates, both the first ratchet 104 and the second ratchet 105 rotate, and the vibration drill operates in the drill mode.
[0047]
On the other hand, when the magnet of the change lever 126 is de-energized, the change ball 129 engages with the concave portion of the outer cylinder portion 105b, and the state shown in FIG. 18 is obtained. Therefore, when the cylinder 102 rotates, the first ratchet 104 rotates, but the second ratchet 105 does not rotate. Therefore, a striking force is generated by the serrated uneven surface between the first and second ratchets, and the vibration drill is in the vibration drill mode. Works with. In this embodiment, the second ratchet 105 is in a floating state even when operating in the drill mode. Further, since vibrations oscillated by the first and second ratchets 104 and 105 are difficult to be transmitted to the main body frame portion, vibrations transmitted to the user are reduced.
[0048]
Further, since the frictional force acting between the second ratchet 105 and the outer cylindrical portion 105b is reduced by the rolling of the ball 129, the friction loss can be reduced.
(Fourth embodiment)
FIG. 19 shows another embodiment of the vibration drill of the present invention, and the same components as those of FIGS.
[0049]
In this embodiment, a ratchet holder 130 that is an anti-rotation part of the ratchet 105 is formed on the outer periphery of the outer cylindrical portion 105 b of the second ratchet 105, and an elastic body 131 is interposed between the ratchet holder 130 and the main body frame portion 101. Is provided.
[0050]
In this case, the first spring 120 not only makes it difficult for the vibration of the second ratchet 105 to be transmitted to the main body, but even if the vibration is transmitted, it is buffered by the elastic body 131 so that the vibration transmitted to the user is further reduced. Get smaller.
[0051]
【The invention's effect】
As is apparent from the above description, the present invention relates to the axial vibration of the spindle caused by the relative movement of the first ratchet relative to the second ratchet, causing the second ratchet to repeatedly contact and move away from the first ratchet. A first spring for urging the second ratchet in one axial direction of the spindle, and a second spring for urging the second ratchet in the other axial direction of the spindle. Is elastically held from the main body frame, so that vibrations generated by the first and second ratchets are less likely to be transmitted to the vibration drill main body. Therefore, there is no discomfort for the user of the vibration drill, and there is no concern about harm to health.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a conventional vibration drill.
FIG. 2 is an explanatory diagram of a drill mode of a vibration drill.
FIG. 3 is an explanatory diagram of a vibration drill mode of the vibration drill.
FIG. 4 is an explanatory diagram of a vibration drill mode of the vibration drill.
FIG. 5 is a partial configuration diagram showing another example of a conventional vibration drill.
FIG. 6 is a cross-sectional view showing a first embodiment of a vibrating drill according to the present invention.
FIG. 7 is an explanatory diagram when the pressing force is small in FIG. 6 showing the first embodiment.
FIG. 8 is an explanatory diagram when the pressing force is large in FIG. 6 showing the first embodiment.
FIG. 9 is an explanatory view of a vibration transmission mechanism in the vibration drill according to the present invention.
FIG. 10 is a characteristic diagram of vibration transmission of the vibration drill of the present invention.
FIG. 11 is a cross-sectional view showing a second embodiment of the vibration drill according to the present invention.
FIG. 12 is an explanatory diagram when the pressing force is small in FIG. 11 showing the second embodiment.
FIG. 13 is an explanatory diagram when the pressing force is medium in FIG. 11 showing the second embodiment.
FIG. 14 is an explanatory diagram when the pressing force is large in FIG. 11 showing the second embodiment.
FIG. 15 is an explanatory diagram when the pressing force is 0 in the second embodiment.
FIG. 16 is a cross-sectional view showing a third embodiment of the vibration drill according to the present invention.
17 is a cross-sectional view taken along the line AA ′ of FIG.
18 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 19 is a cross-sectional view showing a fourth embodiment of the vibration drill according to the present invention.
[Explanation of symbols]
101: Body frame
102: Spindle
103: Chuck
104: First ratchet
105: Second ratchet
109: Rotating shaft
110: Gear
111: Second pinion
112: Low speed gear
113: High speed gear
114: Clutch disc
117: Change lever
118: Bit
119: Work material
120: First spring
121: Second spring
122: Side wall
123: Spring
124: Bearing
125: Locking member
126: Change lever
128: Washer
129: Change ball
130: Ratchet holder
131: Elastic body

Claims (4)

A body frame portion that forms the outline of the vibration drill and places the built-in parts at predetermined positions;
A motor housed in the main body frame,
A spindle that is rotated by the motor and movable in the axial direction;
A first ratchet fixed to the spindle and capable of rotating and moving in the axial direction together with the spindle;
A second ratchet having a surface of the concavo-convex portion facing the surface of the concavo-convex portion of the first ratchet and provided to slide on the spindle in the axial direction;
The second ratchet is urged in the first ratchet direction, and the first ratchet is rotated relative to the second ratchet to bring both the concave and convex surfaces into contact with and away from each other, thereby causing the spindle to vibrate in the axial direction. In the vibration drill that gives
A first spring for urging the second ratchet in the first ratchet direction between the side wall portion extending in the spindle direction from the main body frame portion and the second ratchet;
A second spring that biases the second ratchet in a direction opposite to the biasing force of the first spring is provided between the main body frame portion and the second ratchet, and the pressing force is applied to the main body frame portion. When not applied and when a light pressing force is applied to the main body frame portion and the first ratchet and the second ratchet are in contact, the second ratchet does not contact the main body frame portion, and is in a floating state with respect to the main body frame portion. A vibrating drill characterized by maintaining. According to claim 1, when the pressing force of 15 to 25 kg f is applied to the main frame portion, the second ratchet and out of engagement with the second spring, the second ratchet biasing of only the first spring Vibration drill characterized by being made.   2. The vibration drill according to claim 1, wherein f / fc is 2 or more, where f is the vibration frequency of the second ratchet and fc is the natural frequency determined by the spring constant of the vibration drill body and the first spring. The vibration drill according to claim 3, wherein f / fc is 3 or more.

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