JP2003244897A - Holding structure for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively cool a portion of a commutator. <P>SOLUTION: In a brush holder 27 comprising a central bearing box 30 and a ring-shaped holder body 28 connected to the box at the external periphery of the box, baffle plates 35, 35 except for a sleeve 31 portion are extended toward the commutator 26 side at the internal periphery of the holder body 28. Using such a configuration, cooling air that has abutted against the baffle plate 35 causes to form guide passages 36, 36, etc., at the brush holder 27, in order to be made to move forward after flowing to the commutator 26 side along the sleeve 31. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for accommodating a motor having a stator and a rotor such as a DC motor or an AC motor together with a brush in a housing such as an electric tool.

[0002]

2. Description of the Related Art An invention disclosed in Japanese Patent Application Laid-Open No. 2000-341903, which is a prior application of the applicant of the present application, is known as a housing structure for the motor. FIG. 4 shows an impact driver 50 to which the invention is applied. Reference numeral 52 denotes a DC motor including a stator 53 and a rotor 54, which is housed in the housing 51. The rear portion (left side in FIG. 4) of the rotor 54 is formed by a brush holder 55 that is separate from the housing 51. It is pivotally supported. That is, the brush holder 55 integrally has a holder body 57 that holds the pair of brushes 56, 56 and a bearing box 59 that holds a ball bearing 58 that pivotally supports the rotor 54, and the holder body 57 and the housing 51. Rubber pin 6 interposed between the inner surface
0, 60, ..., It is elastically supported in the housing 51. On the other hand, the rotor 54 has a fan 6
1, the outside air is sucked in through the intake ports 62, 62, ... Formed at the rear end of the housing 51, and is discharged through the exhaust ports 63, 63 ,. The commutator 64 portion of 54 can be cooled.

[0003]

In the motor housing structure described above, it is possible to effectively prevent the occurrence of vibration and disconnection, and the holder body 57 and the bearing box 59 are in the same phase, which may cause commutation failure or malfunction. This is preferable because it has the advantage that the life of the brush is less likely to be shortened. However, the cooling air flows from the intake ports 62, 62, ... Between the holder main body 57 and the bearing box 59 to the fan 61, so that the surface of the commutator 64 is, as indicated by a dotted arrow in FIG. The portion of the commutator 64 which flows in parallel with the brush 56 and is in sliding contact with the brush 56 is not cooled effectively. On the other hand, if the fan 61 is enlarged in order to obtain the required cooling effect, the housing 51 will be enlarged.

Therefore, an object of the present invention is to provide a motor housing structure capable of efficiently cooling a commutator portion of a motor without changing the shape of the fan.

[0005]

In order to achieve the above object, the invention according to claim 1 forms a guide passage in the brush holder for guiding cooling air to the commutator side along the brush. It is a feature. According to a second aspect of the present invention, in addition to the object of the first aspect, the brush holder connects the central bearing holding portion and the ring-shaped brush holding portion arranged on the outer periphery thereof with a plurality of connecting pieces, In a device for passing cooling air between the bearing holding part and the brush holding part, the cooling air is provided by a baffle plate protruding near the brush on the inner circumference of the brush holding part in order to easily form a guide path. Is guided to the commutator side. According to a third aspect of the invention, in addition to the object of the second aspect, a baffle is provided between the bearing holding portion and the brush holding portion so that the cooling air can be used for cooling the commutator portion without waste. It is closed except for the plate part.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a rechargeable impact driver 1 to which a motor housing structure of the present invention is applied. A housing 2 is a combination of a pair of half-split housings 3 and 4 which are vertically divided as shown in FIG. , Screwed and formed. Reference numeral 5 denotes a switch, which is provided with a switch trigger 7 that is connected to a battery pack (not shown) that is detachably mounted under the housing 2 with lead wires 6 and 6 and that is biased to project forward (to the right in FIG. 1). There is. Also,
Reference numeral 8 denotes a DC motor including a stator 9 and a rotor 10. The stator 9 has a cylindrical yoke 11 and permanent magnets 12 and 12 fixed to the inner surface of the yoke 11, and the housing 2
In the assembled state, the ribs 13, 13 ... Protruded on the inner surfaces of the half housings 3, 4 are supported.

On the other hand, in the rotor 10, its output shaft 1
The front end of 4 is pivotally supported by a ball bearing 16 in a gear housing 15 fixed to the front end of the housing 2, and the rear end is pivotally supported by a ball bearing 17 incorporated in a brush holder 27 described later. The rotation of the output shaft 14 is
It can be transmitted to the bit 20 via a well-known planetary gear reduction mechanism 18 and a hitting mechanism 19. Also, the rotor 10
The fan 21 between the brush holder 27 and the stator 9.
Is installed. The fan 21 is separated from the brush holder 27 by a baffle 22 provided upright on the inner circumference of each of the half housings 3 and 4, and is formed behind the housing 2 and around the yoke 11 as the rotor 10 rotates. Intake port 2
Intake outside air from 3, 23 ...
Exhaust port 2 formed in the housing 2 around the fan 21
The rotor 10 and the stator 9 are cooled by discharging from 5, 25.

As shown in FIGS. 2 and 3, the brush holder 27 includes a ring-shaped holder main body 28 serving as a brush holding portion, and four connecting pieces 29, 29 ... At the rear center of the holder main body 28. The bearing box 30 serves as a bearing holding portion that is coaxially and integrally connected, and the ball bearing 17 that supports the rear end of the output shaft 14 is held in the bearing box 30. In addition, the holder main body 28 includes a metal sleeve 31, 31 having a rectangular cross section.
Are fixed in the radial direction so as to pass through between the connecting pieces 29, 29, and the carbon brushes 32 are inserted in the sleeves 31, 31, respectively. Each of the carbon brushes 32 protrudes toward the center by a coil spring (not shown) arranged between the brush cap 33 and a brush cap 33, which is connected to the brush cap 33 via a pigtail (not shown). Rotor 10
It comes into contact with the commutator 26.

In the brush holder 27, between the connecting pieces 29, 29 through which the sleeve 31 does not pass (upper and lower in FIG. 2).
Walls 34, 34 are formed on the inner wall of the holder 34 to close the space between the holder body 28 and the bearing box 30. On the other hand, the space between the connecting pieces 29, 29 through which the sleeve 31 passes (left and right in FIG. 2) is a space through which cooling air can pass in the axial direction. A pair of baffle plates 35, 35 for partitioning the space except for the sleeve 31 are provided to protrude toward the commutator 26 side. Therefore, in the brush holder 27, the cooling air that has entered only between the connecting pieces 29 having the sleeves 31, 31 comes into contact with the baffle plate 35 to the commutator 26 side, as shown by the dotted arrow in FIG. After the direction is changed to, the guideway 3 that contacts the commutator 26 and moves forward
6, 36 ... Will be formed.

Reference numerals 37, 37 denote male screw portions 3 formed on the outer periphery of the holder main body 28 in the storage portions of the sleeves 31, 31.
With a holder cap that is screwed to 8, 38 to close the relevant portion, the carbon brush 32 can be replaced by exposing the brush cap 33 by removing the holder cap 37. Further, 39, 39 are lead wires connecting the switch 5 and each sleeve 31.

On the outer periphery of the holder main body 28, the support pieces 40, 40, ... Are respectively in the left-right direction above and below the holder main body 28 and in the up-down direction on the left and right sides of the holder main body 28, and the tips of the support pieces are not in contact with each other. It is projected so that. At the center of each support piece 40, a slit 41 is formed from the tip to give elasticity to the support piece 40. On the other hand, on the inner surface of each of the half housings 3 and 4, the supporting pieces 40 and
Receiving seats 42, 4 into which the shapes of the corners formed by each other can be fitted
2 are formed respectively, and when the brush holder 27 is assembled to the housing 2, the brush holder 27 is attached to each receiving seat 4
Housing 2 via support pieces 40, 40 fitted in 2.
It will be elastically supported within.

In the rechargeable impact driver 1 configured as described above, when the DC motor 8 is driven by the operation of the switch trigger 7 and the rotor 10 rotates, the fan 21 rotates and the intake port 23 of the housing 2 23.
. And 24, 24 ....., Cooling air is sucked, passes through the brush holder 27 and the DC motor 8 in the housing 2, and is discharged from the exhaust ports 25, 25. When passing through the brush holder 27, the cooling air flows through the walls 34, 34.
It enters into the guide path 36 from between the connecting pieces 29, 29 without a wire, and is guided to the commutator 26 side (axial center side of the rotor 10) along the sleeve 31 by the baffle plates 35, 35 as described above. After coming into contact with 26, it will move forward. Therefore, the cooling air can reliably pass through the commutator 26 portion with which the carbon brush 32 is in sliding contact and can be cooled.

As described above, according to the motor housing structure of the above embodiment, the brush holder 27 is provided with the guide passage 36 for guiding the cooling air to the commutator 26 side along the carbon brush 32. Commutator 2 with which 32 slides
Six parts are cooled efficiently. Therefore, a sufficient cooling effect can be obtained without increasing the size of the fan. In particular, the baffle plate 35 protruding near the sleeve 31 on the inner circumference of the holder body 28 allows the cooling air to flow through the commutator 26.
By being able to guide to the side, the guide path 36 can be easily formed. Further, since the space between the holder main body 28 and the bearing box 30 is closed by the wall 34 except between the connecting pieces 29, 29 where the baffle plate 35 is provided, the cooling air is not wasted in cooling the commutator 26 portion. It is available.

The wall 34 is not always necessary,
Even if the wall 34 is eliminated, the effect of guiding the cooling air to the commutator 26 side by the baffle plate 35 can be obtained, and the guide path can be formed. Further, the baffle plate may be a single continuous sheet as long as it does not interfere with the sleeve, or the tip may be further extended as long as it does not interfere with the commutator.

[0015]

According to the first aspect of the present invention, since the brush holder is provided with the guide path for guiding the cooling air to the commutator side along the brush, the commutator portion with which the brush is in sliding contact is efficient. Well cooled. Therefore, a sufficient cooling effect can be obtained without increasing the size of the fan. According to the invention of claim 2, in addition to the effect of claim 1, the brush holder connects the central bearing holding part and the ring-shaped brush holding part arranged on the outer periphery thereof with a plurality of connecting pieces. However, in the case of passing cooling air between the bearing holding portion and the brush holding portion, the baffle plate protruding near the brush on the inner circumference of the brush holding portion directs the cooling air to the commutator side. By being able to guide, the guide path can be easily formed.
According to the invention described in claim 3, in addition to the effect of claim 2, the space between the bearing holding portion and the brush holding portion is closed except for the baffle plate portion, so that the cooling air is commutated. It can be used for cooling parts without waste.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an impact driver.

FIG. 2 is a cross-sectional view of an impact driver when the brush holder is viewed from the rear.

FIG. 3 is a perspective view of the brush holder (shown with the bearing box down).

FIG. 4 is a vertical sectional view of a conventional impact driver.

[Explanation of symbols]

1 ... Impact driver, 2 ... Housing, 8 ...
DC motor, 9 ... Stator, 10 ... Rotor, 21 ...
Fans, 23, 24 ... Intake port, 25 ... Exhaust port, 26
..Commutator, 27..Brush holder, 28..Holder body, 29..Coupling piece, 30..Bearing box, 3
1 ・ ・ Sleeve, 32 ・ ・ Carbon brush, 34 ・ ・
Walls, 35 ... Baffle plates, 36 ... Taxiways.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H609 BB06 BB12 BB18 PP13 PP14                       QQ02 QQ14 RR03 RR16 RR27                       RR38 RR41                 5H613 BB14

Claims (3)

[Claims] 1. A brush holder in which a bearing holding portion for holding a bearing of a rotor of a motor having a commutator and a brush holding portion for holding a brush of the motor are integrated is held in a housing, while the rotation is performed. It is a housing structure of a motor that allows a cooling air sucked into the housing to be passed through the brush holder and discharged to the outside of the housing by a fan provided in a child, the cooling air being supplied to the brush holder. A housing structure for a motor, characterized in that a guide path is formed along the brush toward the commutator side. 2. A brush holder connects a central bearing holding part and a ring-shaped brush holding part arranged on the outer periphery thereof with a plurality of connecting pieces, and cools between the bearing holding part and the brush holding part. 2. The motor according to claim 1, wherein the cooling air can be guided to the commutator side by a baffle plate protruding near the brush on the inner circumference of the brush holding portion. Containment structure. 3. The motor housing structure according to claim 2, wherein a space between the bearing holding portion and the brush holding portion is closed except for a baffle plate portion.