JPH0660274U - Three-layer brush - Google Patents

Abstract

(57) [Summary] [Objective] The present invention is particularly advantageous for a power tool with a built-in motor, but an object of the present invention is to develop a brush that can be used for a general-purpose motor. [Structure] A brush material 1'of an abrasive material is arranged in the central layer, and brushes 2'of a long-life material having no abrasive material are arranged on both sides to integrate the three layers, and the three-layer brush leads. A three-layer brush in which one end of the wire 3 is embedded and fixed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a three-layer brush, and is configured to be used for both an electric tool motor with a brake function and a motor that does not require a brake function.

[0002]

[Prior art]

In the present specification, a brake material is a brush material having coarse particles, relatively high resistivity, relatively low apparent specific gravity, abrasiveness, a lot of commutator wear, and a short brush life (hr). That is, typical examples are an apparent specific gravity of 1.40, a resistivity (μΩ · cm) of 60500, a Shore hardness of 30, and a bending strength of 230 Kg / cm ² . A long-life material is a brush material with fine particles, a relatively low resistance ratio, a relatively high apparent specific gravity, no abrasiveness, little commutator wear, and a long brush life (hr). Has an apparent specific gravity of 1.53, a resistivity (μΩ · cm) of 46900, a Shore hardness of 41, and a bending strength of 340 Kg / cm ² .

Motors for electric tools, especially motors for electric tools with a built-in motor, such as a handheld sander, are required to ensure the safety of the user. Is required and has been adopted as a generator. However, when using a brush made from a brake material for a general-purpose motor without a brake circuit, the brush life is short and commutator wear is large, which is a disadvantage.

[0004]

[Problems to be solved by the device]

 The present invention is particularly advantageous for a power tool with a built-in motor, but it is an object of the invention to solve the development of a brush that can be used for a general-purpose motor, and is an object of the invention.

[0005]

[Means for Solving the Problems]

 The present invention, which meets the above-mentioned object, has a brush made of abradable brake material on the central layer and brushes made of a long-life material not abraded on both sides to integrate the three layers. The present invention relates to a three-layer brush in which one end of a lead wire is embedded and fixed in the three-layer brush.

[0006]

[Action]

 The three-layer brush of the present invention has the brush 1'of the brake material 1 having abrasiveness on the central layer and the brushes 2'of the long-life material 2 having no abrasiveness on both sides thereof. '1'2' is one brush, and one end of the lead wire is embedded and fixed in the three-layer brush, and the thickness dimension of each layer of the three-layer brush shown in the embodiment, 1: 1: Regarding brush No. 1, the results of experiments conducted under the conditions of [10 seconds no-load operation, 3 seconds stop, 10000 repetitions] for the brush used in the motor with stop circuit, and for the motor without stop circuit [20 seconds Table 1 shows the results of the experiment conducted under the conditions of no load operation, 5 seconds stop, 10,000 times.

[Table 1] As is clear from this table, it can be judged that the three-layer brush of the present invention can be used for a motor for a power tool with a stop circuit and a motor without a stop circuit.

[0007]

1 is a perspective view and FIG. 2 is a side view. 1 and 2 show an embodiment of the present invention, in which a brush 1'made of a brake material 1 is arranged on the central layer and brushes 2 ', 2'made of long-life materials 2 and 2 are arranged on both sides. The three layers are manufactured by a single press for brush manufacturing, and one end of the lead wire 3 is embedded and fixed in the three-layer brush at the time of manufacturing. The concave arc surface on the opposite side to the embedded lead wire is the surface that contacts the rotor, and the arrow indicates the direction of rotation of the rotor. The ratio of the thickness dimension of each layer is set to 1: 1: 1, but it was clarified by experiments that it is effective even if the central layer is 10% to 70%. Regarding the brake material 1 and the long-life material 2 of the brush having the above structure,

As defined in the section. The apparent specific gravity, resistivity, Shore hardness, bending strength, etc., were the same as those described in the section as a typical example.

[0008]

[Effect of device]

 The three-layer brush of the present invention can be used for both a small motor for a power tool with a stop circuit and a small motor without a stop circuit, as has been clarified in the section of operation. Since the brush made of brake material used for small motors had a brush life (hr) of 40 and commutator wear (Фmm / 100hr) of 1.20, the brush life was extended especially for small motors for power tools with stop circuits. The effect is to reduce commutator wear.

[Brief description of drawings]

 The accompanying drawings show one embodiment of the present invention,

FIG. 1 is a perspective view.

[Figure 2] Side view

[Explanation of symbols]

1 brake material, 1'brush, 2 long life material, 2'brush, 3 lead wire

Claims (1)

[Scope of utility model registration request] 1. A brush material made of abrasive material having abrasiveness is disposed on the central layer, and brushes made of long-life material having no abrasiveness are disposed on both sides to integrate the three layers, and the three-layer brushes are made of lead wires. A three-layer brush with one end embedded and fixed.