JPH11190296A - Motor driven blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure stable and high airtightness even against a flaw of an air flow inlet of a fan and to improve efficiency of a blower by using a putty seal for a sealing member. SOLUTION: A putty seal 21 which is not low in elasticity as polytetrafluoroethylene or the like but constantly maintains initial flexibility in a clay type regardless of elasped time for a sealing member is filled in a ring groove provided toward the outside from an air flow inlet of a casing 14. As it is rich in flexibility in comparison with PTFE by using the putty seal 21, it is possible to follow up eccentricity of a fan 12, deflection of the fan 12 during driving of a motor driven blower, etc. Additionally, even when there is a flaw on a head end of the fan, the head end of the fan 12 is already put in the putty seal 21 at the time of assembly. Additionally, as the putty seal 21 is soft, even when there is the flaw on the head end of the fan 12 or a middle of the putty seal 21 is damaged, the flaw is buried with time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower using a centrifugal fan.

[0002]

2. Description of the Related Art The structure of a blower comprising a centrifugal fan and a rectifying plate and the structure of a motor for driving the blower are as shown in FIG. 12). The fan 12 draws in external air from the air inlet 15 and discharges it from the outlet. The discharged airflow is decelerated through the current plate 13 and exhausted through the inside of the electric blower 1.
The air flow that has flowed out of the fan 12 is
3 passes through the gap between the casing 14 and the fan 12 again.
It is known that the air blower flows into the air intake of the electric blower 1 and significantly lowers the efficiency of the electric blower 1.

For this reason, a member (hereinafter referred to as a sealing member) 17 such as PTFE (polytetrafluoroethylene) is attached to an overlapping portion between the air inlet of the fan 12 and the casing 14, and the fan 12 and the sealing member are assembled at the time of assembly. 17 is pressed into contact, and when the electric blower 1 is operated thereafter, the tip of the fan 12 cuts the overlapping portion of the seal member 17 with the fan 12 so that the seal member 17 has the same shape as the tip shape of the fan 12. Of the casing 1
The inside of the fan 4 and the air inlet of the fan 12 are kept airtight to prevent the efficiency of the electric blower 1 from decreasing.

[0004]

Conventionally, the casing 14
The seal member 17, which has been used to keep the inside and the air intake of the fan 12 airtight and prevent the efficiency of the electric blower 1 from decreasing, is cut by the fan 12 together with the operation of the electric blower 1 so as to have the tip shape of the fan 12. According to the conventional method of forming airtight grooves by forming mating grooves, not only the flexibility of the seal member 17 is low and the followability to the swing of the fan 12 during operation of the electric blower is low, but also the fan 12 at the time of manufacturing the fan 12 is reduced.
If the tip of the fan 12 is damaged or the entrance of the fan 12 is eccentric, a groove larger than the tip of the fan 12 is formed, and sufficient airtightness cannot be obtained in many cases.

The sealing member 17 is also punched out of a large sheet material into an annular shape having a hole having the same diameter as the air inlet 15 of the casing 14, so that a large amount of material is wasted. There is also known a method in which the cut material is wound around the air inlet 15 of the casing 14 and fixed, but this method requires much labor since the waste of the material is improved but the assemblability is poor.

[0006]

In order to solve the above-mentioned problems, according to the present invention, the seal member 17 is not made of a material having low flexibility such as conventional PTFE (polytetrafluoroethylene), and is not affected by the elapse of clay-like time. A member that always maintains the initial flexibility (hereinafter referred to as a putty seal) is filled into an annular groove provided from the air inlet 15 of the casing 14 to the outside thereof. By using putty seal, conventional PTFE
(Polytetrafluoroethylene) is softer than PTFE (Polytetrafluoroethylene) and follows the eccentricity of the fan 12 and the runout of the fan 12 during operation of the electric blower. With the seal member 17 using fluoroethylene), the seal member 17
When the electric blower 1 starts operation only when the surface of the seal member 17 is in pressure contact with the fan 12, a groove having a radius of a distance at a portion farthest from the rotation center is formed at a depth corresponding to the overlap between the surface of the seal member 17 and the fan 12. The sealing effect has been remarkably reduced because the gap between the fan 12 and the seal member 17 has been increased, but the putty seal has been used for the seal member as in the present invention. Since the tip enters the sealing member, and the sealing member is soft, the tip of the fan 12 has a flaw, and even if the sealing member is damaged, the flaw is filled with time. The wound part has a wider groove, but the other part conforms to the shape of the tip of the fan 12, so that sufficient sealing performance can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 2 shows the internal structure of a conventional electric blower 1. The electric blower 1 includes an outer frame 2, a stator 3 fixed to the outer frame 2, a bearing 4 a provided on the outer frame 2, and a rotating shaft 5 supported by a bearing 4 b provided on an end bracket 16. Fixed rotor 6, rotating shaft 5
And a brush 9 for making electrical connection with the commutator 7 and a holder 9 for holding the brush and fixing the brush to the outer frame 2.

The commutator 7 has commutator segments on its circumferential surface, and each commutator segment is connected to a coil in the rotor 6.

The brush 8 is housed in a holder 9 and has a spring 1
It is pressed against the commutator 7 by 0 and is in sliding contact with the commutator 7. Reference numeral 11 denotes a lead wire electrically connected to the brush 8 for connecting the brush 8 to an external electrode, and is connected to a terminal (not shown) provided on the holder 11.

At one end of the rotating shaft 5, a centrifugal fan 12 is fixed to the rotating shaft 5 by screws 20, and is constituted by a rectifying plate 13 for rectifying the air flowing out of the fan 12, and a casing 14 for covering the fan 12 and the rectifying plate 13. You.

When the electric blower 1 starts rotating, the rotor 6
Rotates, and the fan 12 provided coaxially with the rotor also rotates. When the fan 12 rotates, air flows in from the air inlet 15 of the casing 14 and is exhausted to the motor side through the fan 12 and the rectifying plate 13. The fan 12 is a casing 14
Is in contact with the hermetic seal 17 provided at The hermetic seal 17 is made of PTFE (polytetrafluoroethylene) resin and has a high heat resistance and a small friction at a contact portion with the fan. When the casing 14 is assembled, it is merely in pressure contact with the fan 12 as shown in FIG. 3A. However, when the motor is energized for the first time after assembly, it is cut by the air inlet of the fan 12 with its rotation. ), And a sealing effect occurs.

However, as shown in FIG. 4A, if there is a flaw such as a dent formed at the time of manufacturing the fan 12 at the air inlet of the fan 12 as shown in FIG.
2 is sharply cut away from the point farthest from the rotation center of the tip, that is, a circle having a radius at the tip of the wound.
A gap is formed between the outside of the airtight seal 17 and the fan 1
A part of the air flow discharged from the fan casing 14
Flows through the gap between the fan and the fan 12, and the efficiency of the blower decreases.

If the center of the air inlet of the fan 12 does not coincide with the center of the rotating shaft as shown in FIG.
L2) A gap is generated between the hermetic seal 17 and the fan 12, and the sealing effect is significantly reduced. FIG. 6 is an enlarged view of a contact portion between the fan 12 and the hermetic seal 17, but the hermetic seal 17 has been largely removed due to the eccentricity of the fan 12. When the fan 12 rotates from this state, the tip of the fan 12 moves from the inside to the outside of the groove formed in the hermetic seal 17 because the fan 12 is eccentric, and does not contact the seal during the movement, As in the case of the scratch at the tip of the air inlet of the fan 12, the efficiency of the blower is reduced. As shown in FIG. 1, in the present invention, a seal member having a low elasticity such as a conventional PTFE (polytetrafluoroethylene) is used to solve the above-mentioned problems that occur when the conventional hermetic seal 17 is used. Rather than a clay-like material that keeps its initial flexibility regardless of the passage of time (hereinafter referred to as putty seal)
21 is filled into an annular groove provided from the air inlet 15 of the casing 14 to the outside thereof. Putty seal 21
By using, it is more flexible than conventional PTFE (polytetrafluoroethylene), so it follows the eccentricity of the fan 12 and the run-out of the fan 12 during operation of the electric blower. Even if there is a scratch, FIG.
As shown in (1), the tip of the fan 12 has already entered the putty seal 21 at the time of assembly, and the tip of the fan 12 is scratched because the putty seal 21 is soft.
Even if the middle of the fan 1 is damaged, the wound is filled with time, and when the electric blower 1 is operated, the wound portion at the tip of the fan 12 has a wide groove as shown in FIG. Therefore, sufficient sealing performance can be obtained.

Further, in this embodiment, when the putty seal 21 filled in the groove of the casing is partially filled in the groove of the casing 14, the putty seal 21 is in contact with the fan 12 when the electric blower 1 is operated, and also prevents the putty seal 21 from falling off. Retainer plate 19
Is provided. The holding plate 19 is fixed to the casing 14 by spot welding.

[0016]

Conventionally, airtightness is established between the fan 12 and the casing 14 covering the same, and the air discharged from the fan 12 flows into the fan 12 again through the gap between the casing 14 and the fan 12. PTF between the fan 12 and the casing 14
Hermetic seal 1 made of E (polytetrafluoroethylene)
However, it was not possible to stably obtain the desired effect due to eccentricity or damage of the air inlet of the fan 12 with respect to the rotating shaft 5 or the like. According to the present invention, by using the putty seal 21 having high flexibility for the seal member, a high airtightness can be stably obtained even when the air inlet of the fan 12 is damaged. Can be provided stably.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric blower 1 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional electric blower 1.

FIG. 3 is a partially enlarged view of a contact portion between a fan 12 and an airtight seal 17;

FIG. 4 is a partially enlarged view of a contact portion with a hermetic seal 17 when a tip of a fan 12 has a flaw.

FIG. 5 is a partially enlarged view of a contact portion with a hermetic seal 17 when the tip of a fan 12 is eccentric.

FIG. 6 is a partially enlarged view of an air inlet of the fan 12;

FIG. 7 is a partially enlarged view of a contact portion between the fan 12 and the putty seal 21 in one embodiment of the present invention.

[Description of Signs] 1 ... Electric blower, 3 ... Stator, 5 ... Rotary shaft, 6 ... Rotor, 14 ... Casing, 17 ... Hermetic seal, 18 ... Hermetic seal holder.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisanori Toshima 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division (72) Inventor Hideyuki Harada Higashi Taga, Hitachi City, Ibaraki Prefecture 1-1-1, Machi, Hitachi, Ltd.Electrical Equipment Division, Taga Headquarters

Claims (2)

[Claims] 1. A centrifugal fan and a flow straightening plate, and a casing for covering the centrifugal fan and the flow straightening plate. The casing has an opening at the same center as an air intake of the centrifugal fan, and the opening is An air inlet of the centrifugal fan and a cylindrical opening inside the air inlet of the centrifugal fan, wherein the air inlet of the centrifugal fan overlaps the casing opening. Fill the part with a sealing member that always keeps the initial flexibility regardless of the elapse of clay-like time, the tip of the air intake of the centrifugal fan enters the member with the rotation of the electric motor, and the air intake of the centrifugal fan An electric blower characterized by being airtight with the outside. 2. A casing according to claim 1, wherein an annular groove is provided outwardly from the opening of the casing, and the seal member is filled into the groove, and an opening smaller than the outer diameter of the annular groove is formed. An electric blower, wherein the elastic body is sandwiched between a casing and a casing by a plate member.