JP2001260051A - Electric tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve performance and life of a motor by automatically supplying lubricant to a motor bearing and preventing dust intrusion. SOLUTION: In an electric tool provided with a motor housed in a housing, a power transmission mechanism part transmitting motive power, an inner cover supporting the power transmission mechanism part and a motor bearing, and a space formed between the motor bearing and the inner cover, performance and life of the motor are improved by automatically supplying lubricant to the motor bearing and preventing intrusion of dust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing lubrication means for a motor incorporated in a power tool such as an impact driver, a wrench or a driver drill, which is an impact tool.

[0002]

2. Description of the Related Art Power tools include an impact tool (impact driver, wrench) and a rotary tool (driver drill) shown in FIG. 2, and a motor 1 as a driving source is housed in a housing 1 of these power tools. Have been. The housing 1 shown in FIG. 2 includes a first housing portion 1a for housing the motor 2,
It has a second storage section 1b for storing the storage battery 3 and the switch 4 and the like, and the storage battery 3 is configured to be detachably provided at one end of the second storage section 1b. Also, the first
An aluminum hammer case 6 for accommodating a power transmission mechanism 5 for transmitting the power of the motor 2 to a tip tool (not shown) is adjacent to the housing 1b.

The above impact tool is disclosed in Japanese Patent Application Laid-Open No. 7-237.
No. 152, a power transmission mechanism 5 is provided. Specifically, a steel ball 9 is accommodated in a spindle cam 7a and a hammer cam 8a formed in a spindle 7 and a hammer 8, and both cams are provided. The hammer 8 is configured to slide while rotating on the spindle 7 along the leads 7a and 8a. This allows the anvil 10 to rotate while striking it,
Fastening work such as screws and nuts can be performed. In addition,
As for the mechanism of the impact, as shown in FIG. 3, the hammer 8 rotates forward along the leads of both cams 7a, 8a and strikes the anvil 10 with a diagonal force F. It is generated by the action of F1 and a force F2 that produces an impact action in the axial direction.

A motor 2 electrically connected to the switch 4 in the housing 1 via a lead wire 11 is fixed so as not to move in the housing 1 in the axial direction due to the impact (vibration) described above. I have. As a fixing means, the end cap 2a side of the motor 2 is
And a drive part side of the motor 2 is received by an inner cover 13 via a front damper 12 made of an elastic body, so that the front damper 12 is appropriately compressed in a stationary state. It is considered that the motor 2 is provided. In addition, Innakaba 1
3 is sandwiched between the housing 1 and a hammer case 6 that accommodates a rotation transmission mechanism and a percussion transmission mechanism, which are power transmission mechanisms 5, and the inner cover 13, the hammer case 6, and the housing 1 are fastened with screws or the like. Have been.

The inner cover 13 retains the outer diameter of the ball bearing 14 that rotatably supports the spindle 7 and is fitted to the outer diameter of the motor bearing 2b. Is provided with a front damper 12 for mitigating the above-described impact in the thrust direction and the like. An O-ring 16 for holding the inner cover 13 in the radial direction is inserted into the fitting portion 16, and the thrust of the motor shaft 2c is provided between the inner cover 13 and the outer diameter end surface of the motor bearing 2b. Space (gap) in consideration of backlash in the direction, deflection of damper, cumulative tolerance of each part, etc.
17 are provided.

[0006]

In the above-described conventional power tool, since the lubricating oil of the motor bearing gradually disappears due to the heat generated by the motor, the motor bearing is damaged by friction or the like, and as a result, the performance (efficiency) of the motor is reduced. ) And shorten the life. When the cooling fan of the motor rotates, dust enters the housing through the wind window, and when the dust passes through the motor and adheres to the motor bearing, the motor bearing is damaged by the influence of the dust. As a result, there is the same problem as described above in that the performance and life of the motor are reduced.

An object of the present invention is to solve the above problems and to improve the performance and life of a motor by automatically supplying a lubricant to a motor bearing and preventing dust from entering.

[0008]

SUMMARY OF THE INVENTION The object is to provide a motor housed in a housing, a power transmission mechanism for transmitting the power of the motor, and an inner cover for supporting the power transmission mechanism and the motor bearing. Further, in a power tool including a space formed between a motor bearing and an inner cover, the power tool is achieved by providing a lubricant in the space.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Power tools include impact tools (impact driver, wrench) and rotary tools (driver drill) shown in FIG.
A motor 2 serving as a driving source is accommodated therein. A housing 1 shown in FIG.
a, and a second accommodating portion 1b for accommodating the storage battery 3 and the switch 4 and the like. The second accommodating portion 1b is configured so that the storage battery 3 is detachably provided at one end. Also,
An aluminum hammer case 6 accommodating a power transmission mechanism 5 for transmitting the power of the motor 2 to a tip tool (not shown) is adjacent to the first housing 1b.

In the power transmission mechanism 5 of the impact tool, a steel ball 9 is accommodated in a spindle cam 7a and a hammer cam 8a formed on a spindle 7 and a hammer 8, and a steel ball 9 is accommodated along the leads of the cams 7a and 8a. The hammer 8 slides on the spindle 7 while rotating. As a result, the anvil 10 can be rotated while being struck by impact, so that screws and nuts can be fastened. As for the mechanism of the impact, as shown in FIG. 3, the hammer 8 rotates forward along the leads of both cams 7a, 8a and strikes the anvil 10 with a diagonal force F. Force F1 and the force F that causes an axial impact action
It is generated by the action of 2.

A motor 2 electrically connected to the switch 4 in the housing 1 via a lead wire 11 is fixed so as not to move in the housing 1 in the axial direction due to the above-mentioned impact (vibration). I have. As a fixing means, a rear damper 18 made of an elastic body on the end cap 2a side of the motor 2 is received by a rib 1c,
Through the front damper 12 made of an elastic body on the motor shaft 2c side (opposite the rib side), the inner cover 13 made of aluminum die-casting or resin which is robust and has high heat dissipation so as to withstand the shock generated from the spindle 7 and the like. The inner cover 13 is configured to receive the motor 2 in a position where the front damper 12 and the rear damper 18 are appropriately compressed in a stationary state. Further, the rear damper 18 is arranged in the radial direction in addition to the axial direction of the end cap 2a, so that the end cap 2a does not contact the housing 1 and the rib 1c. Both the axial direction and the radial direction are received by the rib 1c via the rear damper 19. The inner cover 13 is sandwiched between the housing 1 and the hammer case 14 that houses the rotation transmission mechanism and the impact transmission mechanism, which are the power transmission mechanism 5,
These inner cover 13, hammer case 6, housing 1
Are fastened with screws or the like. A rear damper hole 18a is provided near the motor shaft 2c of the rear damper 18, and
In a flow path formed by providing a housing hole 1d communicating with the rear damper hole 18a in the housing 1 near the rear damper hole 18a, a felt or sponge is disposed as a dust suppressing member 19 having a filter function (filtering function). ing. For this reason, the motor 2 can be cooled by the inflow of outside air, and the intrusion of dust can be prevented. The felt or sponge is provided on the rear damper 18 or the housing 1 by using a method such as adhesion so as to close the flow path.

The inner cover 13 holds the outer diameter of the ball bearing 15 that rotatably supports the spindle 7 and is fitted to the outer diameter of the motor bearing 2b. Is provided with a front damper 12 for mitigating the above-described impact in the thrust direction and the like. An O-ring 16 for holding the inner cover 13 in the radial direction is inserted into the fitting portion 15, and a thrust of the motor shaft 2c is provided between the inner cover 13 and the outer diameter end surface of the motor bearing 2b. Space (gap) in consideration of backlash in the direction, deflection of damper, cumulative tolerance of each part, etc.
The space 17 is filled with grease 20 as a lubricant. The grease 20 is:
The grease 20 gradually enters the interior of the motor bearing 2b, for example, when subjected to an impact action, because the viscosity decreases and the fluidity is affected by the influence of heat from the motor. Therefore, the grease 2 is automatically added to the motor bearing 2b.
Since 0 is supplied, troubles due to running out of lubricating oil in the motor bearing 2b can be eliminated, and the performance and life of the motor 2 can be improved.

Further, even if dust that has entered the housing 1 from the wind window further enters the motor 2 due to the rotation of the cooling fan provided in the motor 2, the motor bearing 2b is covered by the above-described grease 20, ie, Since the dust only adheres to the surface of the grease 20 and does not reach the inside of the motor bearing 2b, the performance and life of the motor 2 can be improved without being adversely affected by the dust.

The O-ring 16 disposed on the fitting portion 15
Means that the grease 20 filling the space 17 is
Of the space 1
Grease 2 on the motor bearing 2b by increasing the airtightness of
It works to make 0 easily drawn.

[0015]

According to the present invention, since a lubricant is provided in a space formed between the motor bearing and the inner cover, the lubricant is automatically supplied to the motor bearing and dust can be prevented from entering. Performance and life can be improved.

[Brief description of the drawings]

FIG. 1 is a partially omitted longitudinal side view showing an embodiment of a power tool according to the present invention.

FIG. 2 is a partially omitted longitudinal side view showing one embodiment of a conventional power tool.

FIG. 3 is a state diagram showing a conventional mechanism for generating an axial force due to impact of a hammer and an anvil of a power tool.

[Explanation of symbols]

1 is a housing, 1a is a first housing, 1b is a second housing, 1c rib, 1d is a housing hole, 2 is a motor, 2a
Is an end cap, 2b is a motor bearing, 2c is a motor shaft, 3 is a storage battery, 4 is a switch, 5 is a power transmission mechanism,
6 is a hammer case, 7 is a spindle, 8 is a hammer, 9 is a steel ball, 10 is an anvil, 11 is a lead wire, 12 is a front damper, 13 is an inner cover, 14 is a ball bearing, 15 is a fitting part, and 16 is an O. Ring, 1
7 is a space, 18 is a rear damper, 18a a rear damper hole, 1
9 is a dust suppression member, and 20 is grease.

Claims (2)

[Claims] A motor housed in a housing, a power transmission mechanism for transmitting the power of the motor, and an inner cover for supporting the power transmission mechanism and a motor bearing;
An electric tool having a space formed between the motor bearing and the inner cover, wherein a lubricant is provided in the space. 2. The power tool according to claim 1, wherein the lubricant is grease.