JP3894106B2 - Impact tools - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary impact tool such as an impact driver or impact wrench.
[0002]
[Prior art]
FIG. 5 shows the structure of a conventional impact driver. The battery pack 1 is used as a power source, the impact mechanism is operated by the driving force of the motor unit 3, and the anvil 10 is struck to give a rotational impact force to the tip tool.
[0003]
Hereinafter, the impact mechanism unit will be described. The driving force of the motor unit 3 rotates the spindle 6 via the speed reduction unit 5. The spindle 6 and the hammer 7 are connected by a cam mechanism constituted by a steel ball 8 and a V-shaped cam groove 6b. Further, the hammer 7 is always urged toward the distal end by the spring 9. As a result, when the spindle 10 and the hammer 7 are relatively twisted, the hammer 7 moves backward to the motor unit 3 side, and when released from the twist, rotates and moves forward while being accelerated by the spring 9. In addition, the hammer 7 and the anvil 10 have protrusions 7a and 10C that are relatively disposed at two locations on the rotation plane, respectively. The rotation direction of the bolt, the tip tool, and the anvil 10 is restricted to each other.
[0004]
With the above configuration, the operation of the impact mechanism section will be described. The rotational force of the spindle 6 is transmitted to the hammer 7 through the cam mechanism and starts to rotate together. The protrusions of the hammer 7 and the anvil 10 are engaged before the half rotation. As the spindle 6 and the hammer 7 are twisted relative to each other, the hammer 7 starts to retract while the spring 9 is contracted.
[0005]
Finally, it gets over the height of the convex part and leaves. The hammer 7 is rapidly accelerated in the rotational direction by the elastic energy stored in the spring 9 in addition to the rotational force of the spindle 6 and starts to advance. While the hammer 7 is accelerated, the convex part is engaged again. At this time, a strong rotational impact force is applied to the anvil, and screws and bolts are inserted through the tip tool attached to the anvil tip. Tighten. The above is the rotation hitting cycle. FIG. 4 is an enlarged view of the fitting portion in which the spindle 6 and the anvil 10 and the metal 11 are slidably fitted. The fitting shaft 6a at the tip of the spindle is fitted into a fitting hole provided in the anvil, and an oil sump chamber 10a is provided on the output side. The oil sump chamber 10a and the oil groove 11a provided in the metal 11 are communicated with each other through an oil hole 10b provided perpendicular to the thrust direction of the anvil 10, and grease is supplied to the sump chamber 10a as a lubricant. Filled. This grease is gradually pushed out by changing the pressure in the hammer case due to the reciprocating movement of the hammer 7 when bolts and screws are tightened, passes through the oil hole 10b of the anvil, and is sent to the metal oil groove 10a. The metal 11 is lubricated.
For example, it is disclosed in Patent Document 1.
[0006]
Here, in order to ensure smooth lubrication of the anvil 10 and the metal 11, it is necessary to ensure a fitting distance L1 ′ between the anvil and the metal of a certain dimension or more. Therefore, the position of the anvil oil hole 10b must be provided on the output side of the anvil rather than the fitting distance L1 ′ between the anvil and the metal, and accordingly, the fitting hole depth L2 ′ of the anvil needs to be longer. The distance L3 ′ between the oil sump chamber end face and the bit insertion hole end face must be secured to a certain dimension or more, and the oil hole 10b of the anvil provided vertically has a negative effect on shortening the total length of the anvil. Further, while the bolts are tightened, the hammer 7 and the spindle 6 rotate at a high speed, but the anvil 10 rotates at a very low speed and the grease centrifugal force is reduced. In some cases, grease could not be replenished smoothly.
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-46078
[0007]
[Problems to be solved by the invention]
In the past, there has been an opportunity to use impact drivers in narrow places at construction sites and the like, and it has been desired to be smaller. The problem to be solved by the present invention is to shorten the total length of the anvil and the tool body and to smoothly supply grease to the metal while ensuring the same fitting distance between the anvil and the metal. It is in.
[0008]
[Means for Solving the Problems]
The purpose of the above is to provide the anvil oil hole 10b provided in the anvil of FIG. 1 at a certain angle rather than perpendicular to the thrust direction, thereby reducing the fitting hole depth L2 of the anvil, The overall length of the anvil 10 can be shortened by reducing the distance L3 between the end surfaces of the bit insertion holes. In addition, the diagonal hole generates radial component force in the grease in the oil hole, and the grease can be replenished to the metal more smoothly by vibration from the axial direction from the hammer.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment in which the present invention is applied to a power tool will be described with reference to FIGS.
FIG. 3 shows an electric tool using the battery pack 1 as a power source and the motor unit 3 as a drive source. Except for the shape of the anvil 10, it is as described in the section of the prior art. In order to ensure smooth lubrication between the anvil 10 and the metal 11, the fitting distance L1 between the anvil and the metal needs to be ensured to be a certain dimension or more. Therefore, the position of the oil hole 10b of the anvil must be provided on the output side of the anvil rather than the fitting distance L1 between the anvil and the metal, and the fitting hole depth L2 of the anvil needs to be longer, as shown in FIG. If the anvil fitting hole depth L2 is shortened and the oil hole 10b of the anvil communicating with the oil sump chamber 10a and the metal oil groove 11a is provided at an angle with respect to the thrust direction of the anvil The total length of the anvil can be shortened and the total length of the tool body can be shortened without sacrificing the fitting distance L1 between the anvil and the metal. This can reduce the weight of the tool body, reduce the materials used, and reduce the cost. As shown in FIG. 2, when the axial vibration of the hammer 7 is applied to the anvil 10, the oil hole 10 b of the anvil is oblique, so that the grease 13 in the oil hole has an axial component force fa. A force fr that moves outward along the oblique hole is generated. With this force, the grease 13 tries to move from the inside to the outside, and replenishment of the grease 13 to the metal is assisted. This effect is particularly significant when the anvil is stopped during bolt tightening or during intermittent rotation, that is, when the centrifugal force due to rotation is small.
[0010]
【The invention's effect】
According to the present invention, an anvil oil hole communicating with the oil sump chamber and the metal oil groove is provided at an angle so that the fitting hole of the anvil does not sacrifice the fitting length of the anvil and the metal. By shortening the depth and moving the bit insertion hole to the spindle side, the total length of the anvil can be shortened, and the total length of the tool body can also be shortened. In addition, by shortening the total length of the anvil, it is possible to reduce costs and weight by reducing the amount of material used.
In addition, grease can be replenished smoothly to the metal, and the tool life can be extended.
[Brief description of the drawings]
FIG. 1 is a partial sectional view of an impact tool showing an embodiment of the present invention. FIG. 2 is a partial sectional view of an impact tool showing an embodiment of the present invention. Sectional view of the impact tool according to the prior art. FIG. 5 is a sectional view of the impact tool according to the prior art.
1 is a battery pack, 2 is a switch, 3 is a motor unit, 4 is a housing, 5 is a deceleration unit, 6 is a spindle, 6a is a spindle fitting shaft, 6b is a V-shaped cam groove, 7 is a hammer, 7b is a hammer Projection, 8 is steel ball, 9 is spring, 10 is anvil, 10a is an oil sump chamber, 10b is an anvil oil hole, 10c is an anvil projection, 11 is metal, 11a is a metal oil groove, and 12 is a hammer. Case, 13 is grease, L1 and L1 'are anvil-metal fitting distances, L2 and L2' are anvil fitting hole depths, L3 is the distance between the oil sump chamber end face and the bit insertion hole end face, and fa is the axial direction The force due to the vibration, fr, is an outward force.

Claims (1)

A motor, a speed reducer that decelerates rotation of the motor, a spindle that rotates through the speed reducer, a hammer that transmits the rotational force of the spindle, an anvil that transmits the rotational impact force of the hammer to a tip tool, In an electric tool composed of metal disposed as a bearing for an anvil, an oil sump chamber is provided on the tip tool side of a fitting hole for fitting the spindle and the anvil, and the oil sump chamber and the metal are oil An electric power tool characterized by being communicated by a hole, wherein the oil hole is inclined with respect to a thrust direction of the anvil .

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