JP4046464B2 - Impact tools - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impact tool having an impact force generator.
[0002]
[Prior art]
As shown in FIG. 7, a conventional impact tool (see Japanese Patent Laid-Open No. 59-88264) hits the anvil by the rotational inertia of the hammer, thereby generating an impact rotation on the anvil, thereby mounting the anvil on the anvil. Screws or bolts were tightened with a bit.
[0003]
[Problems to be solved by the invention]
A conventional impact tool generates an impact rotational force necessary for screw or bolt tightening by hitting a hammer and an anvil. For this reason, a hammer and anvil made of steel materials hit each other and hit a large amount of noise. The hammer and anvil striking part is fully closed by the front housing that supports the anvil and the inner cover that supports the spindle that transmits rotation to the hammer, so the noise generated by the hammer and anvil striking part itself Most of is blocked by the front housing. However, simultaneously with this noise, a large vibration is generated in the hammer and the anvil, and the vibration of the anvil is transmitted from the bearing supporting the anvil to the front housing supporting the bearing, thereby vibrating the front housing. When the front housing vibrates, noise is also generated from the front housing. On the other hand, the vibration of the hammer is transmitted from the hammer to the spindle via a spring that is axially biasing the hammer and a ball in the cam groove of the spindle and the spindle, or by contact between the hammer inner diameter and the spindle outer diameter. There is something to communicate. The vibration transmitted to the spindle vibrates the rear housing on the motor side through a bearing supporting the spindle and an inner cover holding the bearing.
[0004]
As described above, since the vibration generated when the hammer and the anvil collide is transmitted to the front housing and the rear housing, a large noise is generated from the front housing and the rear housing in addition to the noise generated when the hammer and the anvil metal collide with each other. There was a problem to do.
[0005]
The object of the present invention is to reduce noise by cutting off the vibration transmission of each part, paying attention to the fact that noise during screw or bolt tightening is generated more than the impact hitting between the hammer and anvil metal. It is to provide impact tools.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the following means are provided so as not to transmit the vibration at the time of impact hitting of the hammer and the anvil to the housing.
(1) A vibration insulating material is provided between the bearing supporting the anvil output shaft and the housing. As a result, the vibration insulating material separates the housing from which the anvil bearing is in contact, so even if the vibration generated in the anvil is transmitted to the bearing, the housing is hardly vibrated by the vibration insulating material. It is possible to suppress noise generation due to vibrations. Here, in a tool using a long bit, the anvil moves in a chopped shape, and the axis of the drive bit attached to the anvil shifts, causing a phenomenon that the screw attached to the drive bit cannot be rotated smoothly. However, in order to suppress this phenomenon, there is also a method of preventing the anvil's pricking motion by lengthening the portion supporting the bearing.
(2) Normally, the housing is divided into a front housing that surrounds the anvil output shaft and the like, and a rear housing that surrounds the motor and the like, and a vibration insulating material is installed between the front and rear housings. In this case, when the vibration of the anvil is transmitted to the front housing, the front housing vibrates and generates noise. However, the vibration transmission amount of the rear housing is suppressed, and the noise of the rear housing is reduced. Furthermore, it is possible to further reduce noise by lengthening the rear housing and shortening the front housing as much as possible and reducing the surface area of the housing which is a sounding body.
(3) A vibration insulating material is installed between a bearing that is a spindle bearing and an inner cover that supports the bearing. As for the support part of the spindle, the front end shaft of the spindle is inserted into the center hole of the anvil at the front, and the other rear is supported by the bearing. This bearing is normally held by an inner cover, which is in contact with the front and rear housings. Therefore, by inserting a vibration insulating material between the bearing and the inner cover that supports the bearing, the amount of spindle vibration transmitted to the front and rear housings can be reduced, so that noise from the front and rear housings can be reduced.
[0007]
In addition, noise reduction can be achieved more effectively by combining (1) to (3) described above.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The impact tool in a present Example is demonstrated using FIGS. In the figure, an electric motor 2, an inner cover 6, a planetary gear 8, a spindle 14, a spring 12, a hammer 15, and an anvil 17 are arranged in the front housing 10 and the rear housing 1 from the rear, and the anvil 17 is a cross screw driver bit 20. Can be connected. The speed reduction mechanism includes a pinion 5 attached to the motor 2, a ring gear 7, a planetary gear 8, and a needle pin 9, and the planetary gear 8 and the needle pin 9 constitute a part of the spindle 14. When the impact torque is generated, the motor 2 supplied with power from a rechargeable battery (not shown) is driven when the switch 4 arranged on the handle 3 is turned on, and the power of the motor 2 is applied to the tip of the motor 2. The planetary gear 8 is transmitted via the connected pinion 5. The power of the planetary gear rotates the spindle 14 via the needle pin 9, and the rotation of the spindle 14 via the ball 16 disposed between the cam groove 14 a of the spindle 14 and the cam groove 15 a of the hammer 15 causes the hammer 15 to rotate. To communicate. The hammer 15 is urged forward by a spring 12 disposed between the hammer 15 and the planetary gear 8 of the spindle 14 and is pushed forward along the cam grooves 14a and 15a. Thereafter, the hammer claw 15b of the hammer 15 having energy by spring force, rotational speed, and moment of inertia strikes the anvil claw 17b of the anvil 17, whereby the anvil 17 is driven to rotate, and the bit 20 connected to the anvil 17 and Torque is applied to a cross screw (not shown) connected to the tip of the bit, and the screw tightens wood or the like. Thereafter, when the impact energy of the hammer 15 is reduced and the torque of the anvil 17 is reduced, the hammer 15 is repelled from the anvil 17 with the spring back of the screw, and the hammer 15 is reversed along the cam grooves 15b and 14b. While moving in the direction of the motor 2. After the hammer 15 hits the stopper 22 or before it hits the stopper 22, the hammer 15 is pushed back along the cam grooves 15b and 14b again in the direction of the anvil 17 by the compression force of the spring 12, and further the cam groove 14a of the spindle. The hammer 15 is accelerated by the rotation of the spindle 14 via the ball 16 disposed between the cam groove 15a of the hammer. Since the spindle 14 continues to rotate while the hammer 15 reciprocates along the cam grooves 14a and 15a up to the stopper 22, the claw 15b of the hammer 15 gets over the claw 17b of the anvil 17, and again the hammer claw 15b. When hitting the anvil claw 17b, the anvil 15 is hit with the hammer 15 rotated 180 °. In this way, by repeatedly striking the anvil 17 by the axial movement and rotation of the hammer 15, a pulse-like impact torque is generated and the screw is tightened.
[0009]
FIG. 1 shows an example in which a vibration insulating material 21 a is provided between the bearing metal 18 supporting the output shaft of the anvil 17 and the housing 10, and the vibration insulating material 21 a is inserted between the bearing metal 18 of the anvil 17 and the housing 10. As a result, even if the vibration generated in the anvil 17 is transmitted to the bearing metal 18, the vibration is suppressed by the vibration insulating material 21a, and the housing 10 hardly vibrates.
[0010]
FIG. 2 is an example in which a portion that supports the bearing metal 18 is lengthened to increase the support rigidity of the bearing metal 18. For example, when a hard wood is screwed using a long bit, the bit 20 extends from the cross hole of the screw. There is a case where the screw is tightened while pressing the impact tool strongly in the screw axis direction so as not to come off. In such a case, the anvil 17 holding the bit 20 performs a pestle-like motion, and the axis of the bit 20 attached to the anvil 17 is displaced, so that the screw attached to the bit 20 cannot rotate smoothly. Sometimes. Therefore, the bearing metal 18 and the vibration insulating material 21b are turned up to the side surface of the anvil 17 to increase the rigidity of the support portion of the bearing metal 18 to prevent the anvil 17 from being squeezed. In this case as well, the vibration insulating material 21b between the bearing metal 18 and the housing 10 does not cause the housing to vibrate without causing vibration.
[0011]
In FIG. 3, the housing is usually divided into a front housing 10 surrounding the output shaft side of the anvil 17 and a rear housing 1 surrounding the motor 2 side, and a vibration insulating material 21 c is installed between the front housing 10 and the rear housing 1. It is an example. In this case, the vibration of the anvil 17 is transmitted to the front housing 10, so that the front housing 10 vibrates and generates noise. However, the vibration of the front housing 10 is not transmitted to the rear housing 1, and Noise from the housing 1 is reduced.
[0012]
FIG. 4 is an example in which the noise from the front housing 10 of FIG. 3 is further reduced. In this example, the front housing 10 is shortened as much as possible, only the bearing metal 18 of the anvil 17 is supported, and the rear housing 1 is lengthened accordingly. Therefore, by arranging the vibration insulating material 21d between the short front housing 10 and the long rear housing 1, the noise of the housing is reduced only from a small area portion of the front housing 10, and the noise is reduced as compared with the case of FIG. .
[0013]
FIG. 5 shows a method of installing a vibration insulating material 21 e between a bearing 22 that is a bearing of the spindle 14 and the inner cover 6 that holds the bearing 22. As for the support part of the spindle 14, the front end shaft 15 c of the spindle 14 is inserted into the center hole of the anvil 17 on the front side, and the other rear side is supported by the bearing 22. The inner cover 6 that holds the bearing 22 is normally in contact with the front housing 10 and the rear housing 1, and the vibration of the spindle 14 is transmitted to the front housing 10 and the rear housing 1 through the inner cover. Therefore, by inserting the vibration insulating material 21e between the bearing 22 and the inner cover 6 holding the bearing 22, the vibration of the spindle 14 is not transmitted to the front housing 10 and the rear housing 1, and the front housing 10 and the rear housing 1 are not transmitted. It is possible to prevent noise caused by vibration.
[0014]
6 is a view similar to FIG. 7 in which a vibration insulating material 21f is provided between the bearing metal 18 of the anvil 14 and the housing 10, and a diagram in which the vibration insulating material 21f is provided between the bearing 22 which is the bearing metal of the spindle 14 and the inner cover 6. 5 is a method in which a vibration insulating material 21 f is further provided between the ring gear 7, the inner cover 6, and the housing 10, and at the same time, a vibration insulating material 21 f is provided on the inner surface of the housing 10. This example can prevent vibration transmitted to the housing when an impact occurs, and can enhance the soundproofing effect of the housing itself, and can reduce the impact sound between the metal of the hammer 15 and the anvil 17.
[0015]
As described above, by using the vibration insulating material 21, vibration transmission to the front housing 10 and the rear housing 1 can be suppressed and noise can be reduced. Therefore, indoors, at night, and in the vicinity of hospitals, schools, etc. It becomes easy to work.
Thus, noise is prevented, and the vibration insulating material 21 used here can use various vibration-proof rubbers, soft plastics, felts, and the like having a damping effect.
[0016]
【The invention's effect】
According to the present invention, the vibration to the housing due to the hammer and anvil that is the vibration generation source in the impact tool is reduced, so that the worker who uses the impact tool is lightly fatigued even if it is used for a long time. Therefore, workability can be improved and noise can be reduced.
[Brief description of the drawings]
FIG. 1 is a partially omitted vertical side view showing a configuration in which a vibration insulating material is inserted between an anvil bearing metal and a housing according to the present invention.
FIG. 2 is a partially omitted vertical side view showing another configuration in which a vibration insulating material is inserted between an anvil bearing metal and a housing according to the present invention.
FIG. 3 is a partially omitted vertical side view showing a configuration in which a vibration insulating material is inserted between front and rear housings according to the present invention.
FIG. 4 is a partially omitted vertical side view showing a case of a short front housing, which is another configuration in which a vibration insulating material is inserted between the front and rear housings according to the present invention.
FIG. 5 is a partially omitted vertical side view showing a configuration in which a vibration insulating material is inserted between a bearing which is a spindle bearing according to the present invention and an inner cover.
6 is a partially omitted vertical side view showing a configuration in which a vibration insulating material is inserted between an anvil bearing metal and a housing according to the present invention, between a bearing and an inner cover which are spindle bearings, between a ring gear and an inner cover and a housing, and an inner surface of the housing. FIG.
FIG. 7 is a partially omitted vertical side view showing a hitting mechanism portion of a conventional impact tool.
[Explanation of symbols]
Reference numeral 1 denotes a rear housing, 2 denotes a motor, 10 denotes a front housing, 14 denotes a spindle, 15 denotes a hammer, 17 denotes an anvil, 18 denotes a bearing metal, 20 denotes a cross screw driver bit, and 21 denotes a vibration insulating material.

Claims (1)

A hammer that has a driving part, a spindle that is rotated by the driving part, a hammer that has a hammer claw and is movable in the axial direction of the spindle, and an anvil claw that meshes with the hammer claw; An anvil that rotates, a bearing that supports the anvil, a hammer cam formed on the hammer, a spindle cam formed on the spindle, a steel ball that engages the spindle cam and the hammer cam, and a counter drive of the hammer An impact tool including a spring that is constantly energized on the part side, and a housing that houses the anvil, wherein a vibration insulating material is provided between the bearing and the housing , and the vibration insulating material and the The impact tool, wherein the bearing extends to a side surface of the anvil .

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