JPH05321898A - Electric motor driven air pump - Google Patents

Abstract

PURPOSE:To reduce a noise, and provide a small electric motor driven air pump by arranging sound absorbing materials on the whole circumference of an air passage in a noise reducer, and forming the air passage in the perpendicular direction to a rotary shaft of the air pump. CONSTITUTION:Air is introduced to a pump chamber 6 through an air inlet passage 11 which is formed in the perpendicular direction to an air pump rotary shaft 3 and is surrounded with three-layer sound absorbing materials 8, 9 and 10, and the air pressurized in the pump chamber 6 is discharged through an air outlet passage formed integrally with a cover 14. The air inlet passage 11 surrounded with the three-layer sound absorbing material 8, 9 and 10 is formed effectively within range of an outside diameter of a pump part. Thereby, a noise can be reduced, and a small electric motor driven air pump 1 can be also provided. The noise is apt to be leaked easily since the air inlet side is communicated with an air cleaner and reduction is necessary, on the one hand, since the air outlet side is communicated with an exhaust pipe of an engine, the noise is hardly leaked, so that the necessity of the reduction is low.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system of an automobile engine, and in particular, by supplying air to the exhaust system, combustion of hydrocarbons and carbon monoxide in exhaust gas is promoted and released to the atmosphere. The present invention relates to an electric motor driven air pump in a secondary air supply device for an automobile engine, which is suitable for purifying engine exhaust gas.

[0002]

2. Description of the Related Art A means for purifying engine exhaust gas released to the atmosphere by supplying secondary air to an exhaust system of an automobile engine to promote combustion of hydrocarbons and carbon monoxide in the exhaust gas. As a secondary air supply system for an automobile engine, for example, P.45 of Automotive Technology Encyclopedia published by Asakura Shoten
4 to P.460 and the like are known techniques. As shown in these figures, in the past, the air pump was generally driven by the engine, and therefore, the output of the engine was consumed in all operating modes. However, nowadays, due to the progress of catalysts, secondary air is not required,
The current exhaust gas regulation values are being satisfied.

In the future exhaust gas regulation, the regulation value becomes stricter, and it cannot be satisfied only with the present catalyst technology, and it is necessary to supply secondary air. However, unlike the air pumps of the past, it is not necessary to supply secondary air in every motion mode, and if the secondary air is supplied only until the catalyst is heated and activated, the exhaust gas regulation value is satisfied. It is becoming possible to do it. Therefore, the secondary air is supplied only for a short time until the catalyst is activated,
After that, in order not to consume the engine output, an electric motor driven air pump that operates the air pump for the short period of time has been proposed (for example, USP4893995). In this electric motor driven air pump, a DC brush electric motor is generally used for cost reduction of the electric motor, and high speed rotation (10,000 rotations or more) is used for downsizing the pump.
It is usually driven in.

However, in such an electric motor driven air pump, noise that causes discomfort to human beings is generated. Conventionally, in order to solve this problem, the Japan Society of Mechanical Engineers, July 10, 1988.
As shown in FIG. 364 of B5 Fluid Machine P153, published by Japan Mechanical Engineering Handbook, a silencer is provided in the air inlet / outlet passage.

[0005]

In the conventional vortex type electric motor driven air pump used for general industry, the stationary type is the outer diameter of the air pump of less than φ200 to φ5.
The outer diameter of the electric motor was smaller than that of the 00 type, and a silencer was provided on the electric motor side. However, for the purpose of supplying the secondary air to the exhaust system of the automobile, it is a necessary condition that the size of the electric motor driven air pump is suppressed to about φ120 × 170 from the viewpoint of vehicle mountability. In this case, the pump part can be downsized by driving the air pump at high speed, but it is difficult to reduce the size of the electric motor as much as the pump part from the viewpoint of service life. Therefore, the muffler must be installed on the pump side, not on the conventional position. However, in this case, the silencer capacity,
It is difficult to secure the length and minimum wall thickness. That is, there is a problem that it is difficult to achieve both reduction of noise and miniaturization.

The object of the present invention is to solve these problems,
An object of the present invention is to provide a small-sized motor-driven air pump with low noise.

[0007]

In the present invention, as means for solving such a conventional technique, a sound absorbing material is arranged around the entire circumference of an air inlet passage, and the air passage is formed in a direction perpendicular to an air pump rotating shaft. Formed. The air inlet / outlet is integrally formed with the cover to increase the volume of the sound absorbing material forming the air inlet passage.

Further, in order to manufacture the sound absorbing material by simply punching out a flat material, the air inlet passage is constituted by three layers of the sound absorbing material.

[0009]

As described above, air is introduced into the pump chamber through the air inlet passage which is formed in the direction perpendicular to the rotation axis of the air pump and which is surrounded by the three layers of sound absorbing material. , Is discharged through an air outlet passage integrally formed with the cover. Since the air inlet passage surrounded by the three layers of sound absorbing material is effectively formed within the outer diameter of the pump portion, noise can be reduced and a small electric motor driven air pump can be obtained. Further, while the air inlet side is communicated with the air cleaner and the noise is likely to leak and needs to be reduced, the air outlet side is communicated with the exhaust pipe of the engine, so the noise is less leaked and the need for the reduction is small.
Therefore, by forming the air outlet passage integrally with the cover and increasing the capacity of the three layers of the sound absorbing material forming the air inlet passage, noise can be further reduced.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. The electric motor driven air pump 1 is fixed to the electric motor 2, the air pump rotating shaft 3, and the shaft 4 of the electric motor 2 which is the air pump rotating shaft, and is rotated integrally with the impeller 5 and the impeller 5.
And a casing 7 forming the pump chamber 6, a sound absorbing material (A) 8, a sound absorbing material (B) 9, a sound absorbing material (C) 10 for reducing noise,
An air inlet passage 11 and an air cleaner (not shown) which are surrounded by the sound absorbing material (A) 8, the sound absorbing material (B) 9, and the sound absorbing material (C) 10 and are formed in the direction perpendicular to the air pump rotating shaft 3. Inlet pipe 1 communicating with and taking in air
2, an outlet pipe 13 that communicates with an engine exhaust pipe (not shown) and sends out pressurized air, a cover 14 integrally formed with the outlet 13 pipe and the inlet pipe 12, and the cover 1
4, an air outlet passage 15 formed integrally with the motor 4, a motor cover 16 for protecting the motor 2, and the motor 2 having a screw (A) 1
7, a housing 18 fixed by 7, an O-ring 19 for keeping the seal between the housing 18 and the casing 7, and a seal rubber (A) for keeping the seal between the casing 7 and the cover 14.
20, a seal rubber (B) 21 for keeping the seal between the housing 18 and the electric motor cover 16, a cover 14, a casing 7, a screw (B) 22 for fixing the housing 18 and the electric motor cover 16 at the same time.

When the impeller 5 is driven by the electric motor 2, air enters from the inlet pipe 12 and is introduced into the pump chamber 6 via the air inlet passage 11, and the air is pressurized in the pump chamber 6 to generate air. It is discharged from the outlet pipe 13 through the outlet passage 15 and is supplied to the engine exhaust system as secondary air.

According to this embodiment, the sound absorbing material (A) 8, the sound absorbing material (B) 9, and the sound absorbing material (C) 10 which have the minimum wall thickness and the minimum capacity necessary for reducing noise are made compact. It is possible to effectively obtain the air inlet passage 11 within the range of the outer diameter of the electric motor drive air pump 1 that has been optimized. Further, by integrally forming the air outlet passage 15 with the cover 14, the capacities of the sound absorbing material (A) 8, the sound absorbing material (B) 9, and the sound absorbing material (C) 10 can be increased. As a result, it is possible to provide a small-sized motor-driven air pump 1 with low noise, which is comfortable and has the effect of increasing the degree of freedom on the vehicle.

[0013]

According to the present invention, a three-layer sound absorbing material which secures a minimum thickness and a minimum capacity for reducing noise is formed so as to surround the air inlet passage, and further, the outer diameter of the electric motor driven air pump is reduced. Since the air inlet passage is effectively constituted within the range, it is possible to provide a small motor driven air pump with low noise. In addition, this has the effect of being comfortable and increasing the degree of freedom on the vehicle.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an air inlet side of an embodiment.

FIG. 2 is a longitudinal sectional view of an air outlet side of the embodiment.

[Explanation of symbols]

2 ... Electric motor, 3 ... Air pump rotating shaft, 6 ... Pump chamber, 7
... casing, 8 ... sound absorbing material (A), 9 ... sound absorbing material (B),
10 ... Sound absorbing material (C), 11 ... Air inlet passage, 14 ... Cover, 15 ... Air outlet passage.

Claims (2)

[Claims] 1. A motor-driven air pump, which comprises a combination of an electric motor and a vortex type air pump, and has a silencer in front of an air pump inlet, wherein a sound absorbing material is arranged all around an air passage in the silencer, and the air passage is provided. An electric motor-driven air pump, characterized in that it is formed in a direction perpendicular to the rotation axis of the air pump. 2. An electric motor driven air pump according to claim 1, wherein the sound absorbing material is manufactured by punching out a flat material and is formed by stacking three layers to form an air passage.