JPH07328954A - Hammer drill - Google Patents

Abstract

PURPOSE:To provide an operation mode switching device for a hammer drill resolving the problems that the pin shaft of a switching lever is abraded in the operation mode of 'rotation only' and impact force is applied to a tool and having a simple structure and good operability by holding the inner ring of a reciprocating bearing and a clutch with a fixed member. CONSTITUTION:A reciprocating bearing 4 and a clutch 5 are invariably coupled. When the clutch 5 is moved in the axial direction, the coupling between the clutch 5 and an intermediate shaft 3 is released, the rotation transmission to the clutch 5 is insulated, and the abrasion of the pin shaft 6a of a switching lever is reduced. Since a fixed member 7 holding or pinching the clutch 5 or blocking the rotation of the crutch 5 in the operation mode of 'rotation only' is provided, no impact force is applied to a tool 14 due to the sliding friction of the reciprocating bearing 4 in the operation mode of 'rotation only'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hammer drill operation mode switching device.

[0002]

2. Description of the Related Art "Rotation + impact" of a conventional hammer drill,
In the "rotation only" switching device, the clutch and the reciprocating bearing that reciprocates the piston are disengaged from each other, and the rotation transmission to the reciprocating bearing is insulated to set the "rotation only" operation mode. However, since the inner ring of the reciprocating bearing can rotate freely, sliding friction between the inner ring of the reciprocating bearing and the intermediate shaft causes the inner ring of the reciprocating bearing to rotate, which gives a striking force to the tool and causes a large amount of vibration. The operability during work such as tightening was poor. Alternatively, there was a method of reducing the above-mentioned sliding friction by providing a needle bearing or the like inside the reciprocating bearing, but it was expensive, and this method only reduced the sliding friction, and the rotation of the reciprocating bearing was completely reduced. I haven't stopped. Furthermore, the inner ring of the reciprocating bearing becomes thinner, so the problem of easy cracking cannot be ignored. Also, the clutch that converts the rotation of the motor into reciprocating motion and transmits rotation and insulation between the reciprocating bearing and the intermediate shaft is movable in the axial direction on the intermediate shaft and always rotates integrally with the intermediate shaft. It has a structure that Therefore, even when the clutch is disengaged from the reciprocating bearing, the clutch always slides with the part that moves the clutch in the axial direction, the pin shaft of the switching lever, and the pin shaft of the switching lever is worn. It was a switching device with a short life.
Alternatively, it is expensive due to complication and increase in number of parts, such as addition of parts to the sliding part in order to prolong the service life. Alternatively, there has been a method of insulating transmission of rotation to the clutch by disconnecting both the engagement between the clutch and the reciprocating bearing and the engagement between the clutch and the intermediate shaft, but the rotation of the clutch is not completely stopped. Therefore, the clutch was rotated due to sliding friction, which had some effect, but the wear could not be completely prevented.

[0003]

As described above, in the prior art, due to the sliding friction between the inner ring of the reciprocating bearing and the intermediate shaft, the tool is impacted even in the "rotation only" operation mode, and vibration is large. The operability during work such as was poor. Further, since the clutch that constantly rotates, the component that moves the clutch in the axial direction, and the pin shaft of the switching lever are constantly sliding, wear of the pin shaft of the switching lever occurs,
It was a switching device with a short life.

It is an object of the present invention to solve the above problems and provide a hammer drill having a long life and good operability.

[0005]

In the hammer drill operation mode switching device of the present invention, the reciprocating bearing and the clutch are always engaged, and the clutch and the intermediate shaft are disengaged from each other. At this time, it can be achieved by holding or sandwiching the clutch with a fixing member, or locking the rotation of the clutch. Further, in the hammer drill as described above, in which the clutch is biased by the spring in the direction in which the clutch engages with the intermediate shaft, the width L6 of the ring-shaped groove in which the pin shaft of the switching lever formed on the clutch is located ( (Hereinafter referred to as a ring-shaped groove width), an intermediate axial width L7 of the pin shaft of the switching lever (hereinafter referred to as a pin shaft width of the switching lever), and the clutch with a fixed member having a pressure contact or a tightening margin. When inserted, the length L2 of the portion that is held or pinched (hereinafter referred to as the clutch holding length) and the state in which the clutch is moved maximally in the direction of disconnecting the engagement with the intermediate shaft ("rotation only") Distance L1 until the clutch of the operation mode (1) is engaged with the intermediate shaft
(Hereinafter, referred to as a non-engagement distance), from the position of the clutch at which the engagement between the clutch and the intermediate shaft is maximum (“rotation + striking” operation mode), the “rotation only” operation mode state L5 to the clutch (hereinafter referred to as the clutch movement amount) and the intermediate shaft axial movement amount L4 of the switching lever pin shaft (hereinafter referred to as the switching lever pin shaft movement amount).
By providing the dimensional relationship of L1> L4 + L7-L6> L2 and L4> L5, the operability of switching can be improved.

[0006]

In the operation mode switching device for the hammer drill constructed as described above, in the operation mode of "rotation only",
Even if the clutch and the intermediate shaft are disengaged, they are always engaged with the inner ring of the reciprocating bearing, and even if they try to rotate due to sliding friction, the weight becomes heavy. The reduction of pin shaft wear is more effective than the conventional technique. Also, in the "rotation only" operation mode, the clutch and the reciprocal bearing are always engaged by holding or sandwiching the clutch with the fixed member or locking the rotation of the clutch, so that the clutch and the reciprocal bearing are both rotated. It is possible to completely solve the problems that the pin shaft of the switching lever is abraded and the tool is hit with a striking force due to sliding friction in the "rotation only" operation mode.

In the above-mentioned "rotation only" operation mode,
An operation mode switching device for a hammer drill that holds or clamps a clutch with a fixing member, in which the clutch is biased by a spring in a direction in which the clutch engages with the intermediate shaft,
When switching from the "rotation only" operation mode to the "rotation + impact" operation mode, the pin shaft of the switching lever hits the groove wall formed on the clutch, removes the clutch from holding or pinching the fixing member, and the intermediate Move in the direction in which the shaft engages. At this time, the non-engagement distance L1 between the clutch and the intermediate shaft, the clutch holding length L2, the switching lever pin shaft movement amount L4, the clutch groove width L6, and the switching lever pin shaft width L7 are L1. By providing the dimensional relationship of> L4 + L7−L6> L2, the clutch is released from the holding member or the holding member before the clutch and the intermediate shaft are engaged, and the force of the spring for urging the clutch causes the clutch and the intermediate shaft to move. By engaging with, the switching operation can be made smooth. Furthermore, since the pin shaft movement amount L4 of the switching lever and the clutch movement amount L5 are provided in a dimensional relationship of L4> L5, the pin shaft of the switching lever does not come into contact with the clutch in the "rotation + striking" operation mode. Therefore, wear of the pin shaft of the switching lever is completely eliminated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 3, the rotation of a motor 1 is transmitted to an intermediate shaft 3 via an output shaft pinion 1a and a fast gear 2, and a second gear 11 meshes with a second pinion 3a.
The rotation is always transmitted to the tool 14, and the tool 14 is rotated via the cylinder 10. On the other hand, a reciprocating bearing 4 rotatably fitted on the intermediate shaft 3 and an inner ring 4a of the reciprocating bearing.
And the clutch 5 which is always engaged with the claw (in the present embodiment, the claw engagement is adopted, but spline engagement can also be performed) is urged by the clutch spring 8 to engage with the intermediate shaft 3. , The rotation of the motor 1 is transmitted to the reciprocating bearing 4, and the piston 9 is reciprocated. Utilizing the resulting air spring, the impact force is transmitted to the tool 14 via the impact element 12 and the intermediate element 13. That is, FIG. 3 shows an operation mode of "rotation + striking". From the state shown in the figure, by operating the switching lever 6 connected to the outside of the housing 15, the pin shaft 6a of the switching lever is eccentric, the clutch 5 is moved, and the spline between the clutch 5 and the intermediate shaft 3 is moved. Reciprocating bearing 4 if disengaged
The rotation of the motor 1 is not transmitted to the motor, and the operation mode becomes "rotation only". In this state, since the clutch 5 does not rotate and is engaged with the inner ring 4a of the reciprocating bearing, wear of the pin shaft 6a of the switching lever can be reduced with a simple structure. Also, in FIGS. 1 and 2, "rotation only"
FIG. 3 is a longitudinal sectional view of an embodiment of a hammer drill that employs a hammer drill operation mode switching device according to the present invention, in which a fixing member 7 for holding or holding the clutch 5 in the operation mode is provided. FIG. 1 shows a "rotation only" operation mode, and FIG. 2 shows a "rotation + striking" operation mode. Here, the transmission of the rotational force and the striking force to the tool 14 will be described with reference to FIG.
Therefore, the operation mode switching mechanism will be described below. When the operation mode of "rotation + striking" is switched to the operation mode of "rotation only", the pin shaft 6a of the switching lever is eccentrically operated by operating the switching lever 6, and the pin shaft 6a of the switching lever is provided on the clutch 5. The groove wall A5b, the clutch 5 is moved to disconnect the spline engagement between the clutch 5 and the intermediate shaft 3, and the clutch 5 is fixed.
Hold or pinch with. That is, the transmission of rotation to the reciprocating bearing 4 or the clutch 5 is insulated, and the clutch 5 is held or pinched, so that the "rotation only" operation mode is set. As a result, due to the sliding friction, a striking force is applied to the tool 14 or abrasion of the pin shaft 6a of the switching lever can be prevented in the operation mode of "rotation only" by the rotation of the inner ring 4a of the reciprocating bearing or the clutch 5. . On the other hand, from "rotation only" operation mode to "rotation + hit"
When the operation mode is switched to the above operation mode, by operating the switching lever 6, the pin shaft 6a of the switching lever 6 moves the clutch 5 to the upper groove wall 5
Upon hitting c, the clutch 5 is moved to disengage the clutch 5 from the holding or clamping of the fixing member 7, and the force of the clutch spring 8 for urging the clutch 5 engages the spline portion 5d of the clutch and the spline portion 3b of the intermediate shaft. Reciprocating bearing 4 which is engaged and always engaged with clutch 5.
The rotation is transmitted to the tool 14, and a striking force is applied to the tool 14. As a result, the "rotation + striking" operation mode is obtained. here,
In the direction in which the clutch 5 engages with the intermediate shaft 3, the clutch 5
If the urging clutch spring 8 is not provided, the switching operation may not be smooth in some cases, but if the switching is performed while the motor 1 is rotating, the switching operation may be smooth. Next is Fig. 4
As shown in, the non-engagement distance L between the clutch 5 and the intermediate shaft 3
1, clutch holding length L2, switching lever pin shaft movement amount L4, clutch movement amount L5, and ring-shaped groove width L
6 and the pin width L7 of the switching lever are L1> L4 + L
An operation mode switching device for a hammer drill according to an embodiment of the present invention, which has a dimensional relationship of 7-L6> L2 and L4> L5, will be described. If it is provided in such a dimensional relationship, "rotation +
When the operation mode of "striking" is switched to the operation mode of "rotation only", since L1> L2, the clutch 5 is pressed against the fixing member 7 after the clutch 5 and the intermediate shaft 3 are completely disengaged. Since it is inserted with a tightening allowance, when the clutch 5 is held or pinched, it is possible to prevent the clutch 5 from rotating, and the switching operation can be performed well. On the other hand, when switching from the "rotation only" operation mode to the "rotation + batting" operation mode, L4 +
Since L7-L6> L2, the clutch 5 is fixed to the fixing member 7
Can be removed from the hold. Further, since L1> L2, the clutch 5 can be removed from holding or pinching the fixing member 7 before the clutch 5 and the intermediate shaft 3 are engaged with each other, and the clutch 5 and the intermediate shaft 3 can be separated by the force of the clutch spring 8. By engaging them, the switching operation can be made smooth. Further, since L4> L5, the minimum clearance in the axial direction of the intermediate shaft 3 between the clutch 5 and the pin shaft 6a of the switching lever is L4− when the intermediate shaft 3 and the clutch 5 are completely engaged.
Since L5> 0, the pin shaft 6a of the switching lever is not worn in the "rotation + striking" operation mode. Therefore, from the above, in the operation mode of "rotation only", the problem that the striking force is given to the tool 14 and the rotating clutch 5
At the same time, the problem of wear of the pin shaft 6a of the switching lever due to friction with and is completely solved by a simple and inexpensive method.

FIG. 5 is a sectional view of the fixing member 7 taken along the line AA in the state where the clutch 5 according to the above-described embodiment is held or sandwiched by the fixing member 7, and FIGS. 6 to 8 show the fixing member 7. A- of another embodiment according to the present invention in which the shape of
A sectional view is shown.

FIG. 6 is a sectional view taken along line AA of the embodiment in which the fixing member 7 is formed of a thin wall. In this embodiment, when converting from the "rotation + striking" operation mode to the "rotation only" operation mode, the clutch 5 is inserted between two thin walls with a tightening margin, and the clutch 5 is clamped. Rotation of the clutch or the reciprocating bearing 4 due to sliding friction is prevented. Since the fixing member 7 is formed of a thin wall, it is easily deformed, and the clutch 5 is easily inserted between the fixing member 7 and the operation mode switching operation is facilitated. 7 and 8 are sectional views taken along the line AA of the embodiment in which the fixing member 7 is formed by a protrusion extending in the direction of the intermediate shaft 3 axis. In this embodiment, when the "rotation + striking" operation mode is converted to the "rotation only" operation mode, the clutch 5 has an allowance because the fixing member 7 extends in the three axial directions of the intermediate shaft. When inserting, the area in which the clutch 5 and the fixing member 7 interfere is small, so that the clutch 5 can be easily inserted. However, since the interference area is large in the direction in which the rotation of the clutch 5 is prevented, the clutch 5 does not rotate, and the above-mentioned problems can be solved.

In the embodiment described above, when the fixing member 7 is made of an elastic member, the fixing member 7 is easily deformed. Therefore, the clutch 5 is inserted into the fixing member 7 with pressure contact or a tightening margin. It is clear that the operation is easy.

Next, another embodiment according to the present invention shown in FIG. 9 will be described. In this embodiment, the elastic member 21 is fixed on the clutch 5. In this embodiment, when the "rotation + striking" operation mode is changed to the "rotation only" operation mode, the upper elastic member 21 of the clutch 5 is deformed, and the fixing member 7 is inserted with the tightening allowance. However, since the clutch 5 is held or held together with the elastic member 21, the operation can be facilitated. 10 and 11 are cross-sectional views of the hammer drill provided with the fixed projection 20 for locking the clutch in the state of the "rotation only" operation mode in which the projection 5e provided on the clutch 5 is in contact.

[0013]

According to the present invention, by holding the inner ring of the reciprocating bearing and the clutch by the fixed member, the pin shaft of the switching lever is worn and the impact force against the tool is exerted in the "rotation only" operation mode. It is possible to provide an operation mode switching device for a hammer drill that eliminates the problem of giving and is simple and has good operability.

[Brief description of drawings]

FIG. 1 is a longitudinal side view showing a “rotation only” operation mode according to the present invention.

FIG. 2 is a vertical sectional side view showing an operation mode of “rotation + striking” according to the present invention.

FIG. 3 is a vertical sectional side view showing a “rotation only” operation mode in another embodiment of the present invention.

FIG. 4 is a vertical sectional side view showing a switching device unit according to the present invention.

FIG. 5 is a cross-sectional view taken along the line AA showing the “rotation only” operation mode in the present invention.

FIG. 6 is a cross-sectional view taken along the line AA showing the “rotation only” operation mode in the example in which the fixing member according to the present invention has a thin wall.

FIG. 7 is a cross-sectional view taken along the line AA showing the “rotation only” operation mode in the example in which the fixing member according to the present invention includes a protrusion.

FIG. 8 is a cross-sectional view taken along the line AA showing the “rotation only” operation mode in another example in which the fixing member according to the present invention includes protrusions.

FIG. 9 is a vertical cross-sectional side view showing an “rotation only” operation mode in an example in which an elastic member is fixed to the clutch according to the present invention.

FIG. 10 is a vertical cross-sectional side view showing a “rotation only” operation mode in an example in which the clutch upper protrusion according to the present invention is locked by a fixed protrusion.

FIG. 11 is a cross-sectional view taken along line BB showing the “rotation only” operation mode in the example in which the clutch upper protrusion according to the present invention is locked by the fixed protrusion.

[Explanation of symbols]

1 is a motor, 3 is an intermediate shaft, 5 is a reciprocating bearing, 6
Is a switching lever, 7 is a fixing member, 8 is a clutch spring, 9 is a piston, 14 is a tool, L1 is a non-engagement distance between the clutch and the intermediate shaft, L2 is a clutch holding length, L3 is a clutch upper protrusion and a fixing protrusion. And L4 is the switching lever pin shaft movement amount, L5 is the clutch movement distance, L6 is the ring groove width, and L7 is the switching lever pin shaft movement amount.

Claims (9)

[Claims] 1. A reciprocator for transmitting the rotation of a motor to a piston reciprocating portion via an intermediate shaft, rotatably mating on the intermediate shaft, converting the rotation of the motor into a reciprocating movement, and reciprocating a piston. A hammer drill having a bearing and a clutch for controlling rotation transmission between the reciprocating bearing and the intermediate shaft, wherein the clutch is axially movable and engaged with the reciprocating bearing, and is connected to the outside of the housing. A hammer drill, characterized in that a tool for selectively engaging or disengaging the clutch and the intermediate shaft by a switching lever can be rotated and hit, or switched to a rotation mode. 2. When the clutch is moved from the state in which the clutch is engaged with the intermediate shaft by the switching lever to release the engagement with the intermediate shaft, the clutch is pressed against a fixing member which is integral with the housing or is a separate component. 2. The hammer drill according to claim 1, wherein the hammer drill holds the outer peripheral portion of the clutch or holds the outer peripheral portion of the clutch in a state where the clutch and the intermediate shaft are disengaged from each other. 3. The clutch is urged by a clutch spring in a direction in which the clutch engages with the intermediate shaft, and the pin shaft of the switching lever is located in a ring-shaped groove formed on the clutch. Groove width L6 and intermediate shaft axial width L of the pin shaft of the switching lever located in the ring-shaped groove
7 and a direction in which the clutch is disengaged from the length L2 of the clutch that is held or clamped by inserting the clutch into a fixing member with pressure contact or with an allowance. The distance L1 until the clutch in the maximum moved state engages with the intermediate shaft,
The hammer drill according to claim 2, wherein the hammer drill is provided in a dimensional relationship of L1> L4 + L7-L6> L2. 4. A state in which the clutch lever and the intermediate shaft are moved from the clutch position where the engagement between the clutch and the intermediate shaft is maximized in a direction in which the clutch and the intermediate shaft are disengaged by the switching lever. The distance L5 to the clutch position and the amount L4 of movement of the switching lever in the direction of the pin shaft intermediate shaft are L
4. The dimensional relationship of 4> L5 is established.
Stated hammer drill. 5. The hammer drill according to claim 2, wherein the fixing member is made of an elastic material. 6. The hammer drill according to claim 2, wherein the fixing member has a thin wall, and the clutch is held by the fixing member. 7. The hammer drill according to claim 2, wherein the hammer drill comprises a protrusion extending in the axial direction of the intermediate shaft of the fixing member. 8. When the clutch is disengaged from the state in which the clutch is engaged with the intermediate shaft by the switching lever,
The elastic member fixed on the clutch is deformed by the fixing member, and the clutch is held or clamped together with the elastic member in a state where the engagement between the clutch and the intermediate shaft is released. The hammer drill according to Item 1. 9. A clutch provided in a rotation-only operation mode is provided so that a projection provided on the clutch abuts a fixed projection in a state where the clutch and the intermediate shaft are disengaged from each other. 2. The hammer drill according to claim 1, wherein the distance L1 until the engagement and the length L3 at which the clutch upper protrusion and the fixed protrusion interfere with each other are provided in a dimensional relationship of L1> L3.