JPH02196198A - Fan for vehicle - Google Patents

Abstract

PURPOSE:To attempt to reduce noise as well as to enhance the cooing efficiency by arranging that the shape of a sound is properly changed in conformity with the difference in the condition of a draught system at the time of high pressure loss or low pressure loss of an axial flow fan. CONSTITUTION:At the idling time of a high draught system, a working ring 20 is placed at the position a little to the front, and the boundary line 2c of an air conducting part 17 and a releasing part 16 is placed at the adjacent position of the front edge 4a of an oil flow fan 4 to make the forward open angle theta of the releasing part 16 large. On that account, the inflow air along the release part 16 from the blade tip of the fan 4 to the conducting part 17 is decreased, and the turbulence generated at the blade tip of the fan is removed by the leading-edge of the conducting part 17 and the noise generation is reduced. As the loss in the air blasting is decreased when the turbulence and the centrifugal flow at the conducting part 17 are further removed, the cooling efficiency of a radiator 1 is enhanced. Next, since the ring 20 is placed a little to the center when changed to the time of low draught system, and the position of the boundary line 2c is separated from the fan 4 to the extent of distance L making the angle theta small, the turbulence at the blade tip of the fan 4 is made small and the reduction of noise generation and enhancement of cooling efficiency become possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle blower used for cooling a radiator, a condenser, etc. mounted on a vehicle.

[Prior Art] Conventionally, as this type of blower, an axial fan 32 rotated by a motor 31 is used, for example, as shown in FIGS. 15 and 16.
and an air conduction section 33 containing the axial flow fan 32.
and a shroud 35 consisting of an opening part 34 that is continuous with the air conduction part 33 and opened to the front of the axial flow fan 32 in order to guide a wide range of air in front of the coaxial flow fan 32 to the air conduction part 33. , those used for cooling the radiator 36 and the like of a vehicle are known.

In this blower, the front resistance varies depending on the shape of the radiator grille, the arrangement of the radiator 36, and the ventilation system conditions such as when the vehicle is idling or driving, and the noise and air volume vary depending on the ventilation system conditions. It is something. However, in reality, the shape and assembly of the shroud 35 and the axial fan 32' are set in a fixed manner depending on certain ventilation system conditions.

That is, in the blower shown in FIG. 15, the boundary 35a between the air conduction part 33 and the open part 34 of the shroud 35 is arranged a predetermined distance rearward from the front edge 32a of the axial fan 32, so that the open part 34 The taper of the open part 34 is made relatively small, that is, the rear end of the open part 34 is disposed further back than the front edge 32a of the axial fan 32, and the inner diameter of the air conducting part 33 that is continuous therewith is made equal over the entire length. According to this shape of the blower, although air flows in from the blade tips of the axial fan 32 when the front resistance is small, such as when the vehicle is running, the air flow of the axial component is stronger, so the air conduction portion Air outflow from 33 became smooth and there were no problems with noise.

[Problem to be solved by the invention] However, when the front resistance is large, such as when idling or when the radiator grill is small, the axial component airflow decreases, but the radial and circumferential airflow decreases, as shown in Figure 16. Since the flow of the component in the direction is maintained without decreasing, the air inflow from the blade tip decreases, causing turbulence near the leading edge of the air conducting section 33 or colliding near the exit of the air conducting section 33. Such centrifugal flow occurs, causing noise.

Therefore, in order to deal with the noise generation when the front resistance is large as described above, the air conduction section 3 is constructed as shown in FIG.
The position of the boundary 35a between the opening part 34 and the axial flow fan 32
The opening part 340 taper is relatively thick (i.e., the rear end of the opening part 34 is arranged close to the front edge 32a of the axial flow fan 3).
It is conceivable to reduce the diameter to the front edge 32a of the air conduction section 32, and then gradually widen the inner diameter of the air conduction section 33 near the outlet 33a to the rear.

However, even with this shape of the blower, when the vehicle climbs a slope at low speed, the forward resistance is large despite the high heat load on the blower, making it impossible to secure a sufficient amount of airflow, resulting in poor cooling efficiency. There is a possibility.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a vehicle blower that can reduce noise and improve cooling efficiency in response to differences in ventilation system conditions.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes an air conduction portion in which air flows and has a cylindrical shape, and from the air conduction portion to the upstream side with respect to the air flow. In a vehicle blower equipped with a shroud consisting of an open part that is continuously opened in a tapered shape, and an axial fan that is enclosed and fixed in the air conduction part and rotated by a drive source, the air conduction part and An actuating member is provided to move the border with the opening part to at least one side of the upstream side or the downstream side with respect to the air flow of the shroud, and this actuating member allows the axial fan to open when the upstream resistance is low and the pressure drop is low. In order to make the taper of the open part relatively small, the boundary position is placed a predetermined distance downstream from the leading edge of the axial fan, and when the upstream resistance of the axial fan is high and the pressure loss is high, the taper of the open part is made relatively small. In order to increase the size, the boundary position is placed close to the leading edge of the axial fan.

[Function] Therefore, in order to make the taper of the opening relatively small during low pressure drop when the upstream resistance of the axial fan is small, the position of the boundary between the air conduction part and the opening part is adjusted by the actuating member from the leading edge of the axial fan. By arranging them a predetermined distance apart on the downstream side, the flow of air flowing in from the opening and passing through the axial fan is directed in the centripetal direction. As a result, the axial component of the air flow becomes stronger, and the air flows out smoothly from the air conducting portion, reducing noise and improving cooling efficiency.

On the other hand, in order to make the taper of the opening relatively large when the upstream resistance of the axial fan is high and the pressure drop is high, the boundary between the air conduction part and the opening part is moved close to the leading edge of the axial fan using an actuating member. This arrangement reduces air inflow from the blade tips of the axial fan, eliminates turbulence near the leading edge of the air conducting portion, and reduces noise.

[First Embodiment] A first embodiment embodying the present invention will be described below with reference to FIGS. 1 to 1.
This will be explained in detail based on FIG.

As shown in FIGS. 1 to 3, a shroud 2 is disposed on the rear side of a radiator l assembled to a radiator grill of a vehicle (not shown) so as to cover the entire surface thereof. Further, an axial fan 4 rotated by a motor 3 serving as a drive source is disposed within the shroud 2.

In this embodiment, the shroud 2 is made of a stretchable material such as rubber and is formed into a substantially funnel shape as a whole, and the inlet 2a side (
A square frame frame 5 is installed on the exit 2b side (front side) and
A circular frame 6 is fixed to each. Both tube frames 5 and 6 are fixed to the frame of the vehicle near the radiator grille, and the shroud 2 itself is supported and fixed.

As shown in Fig. 4, the original shape of the shroud 2 is from the inlet 2a on the upstream side to the outlet 2b on the downstream side with respect to the air flow.
It has a shape that converges continuously to the sides. Further, an actuating ring 7 as an actuating member is attached to the outer periphery of the shroud 2 between the tube frames 5 and 6. As shown in FIG. 5, the operating ring 7 consists of a ring portion 8 and L-shaped arms 9a, 9b, 9c, and 9d that protrude in all directions from the top, bottom, left, and right of the ring portion 8, and includes an upper arm 9a. A rack 9e is provided on the top surface. Further, in this embodiment, the inner diameter of the ring portion 8 is set smaller than the outer diameter of the outlet 2b of the shroud 2.

Then, the ring portion 8 is fitted around the outer periphery of the original shroud 2 shown in FIG. 4 against the tension thereof, and the shroud 2 is
A constriction is formed in the middle of the .

As a result, as shown in FIG. 1.2, the shroud 2 has a substantially tubular air conduction section 10 and an open section continuous to the front side thereof and tapered to introduce air from the radiator 1 side. 11 are provided. Further, due to the taper of the open portion 11, a predetermined front opening angle θ1 is formed on the side of the shroud 2 on the side of the population 2a. Furthermore, the outlet 2b of the shroud 2
Due to the difference between the outer diameter of the ring part 8 and the inner diameter of the ring part 8, the outlet 2b side becomes tapered to widen rearward, and a predetermined rearward opening angle θ2 is formed.

Further, as shown in FIG. 3, in this embodiment, guide frames 12 are provided on the left, right, and lower sides of the radiator l.
The distal ends of the left and right arms 9c, 9d and the lower arm 9b of the actuating ring 7 are supported so as to be reciprocally movable through each guide frame 12.

Then, each arm 9b to 9d in each guide frame 12
The movement of the actuating ring 7 is guided, and the back and forth movement of the actuating ring 7 is guided.

On the other hand, in order to drive the actuation ring 7 back and forth, a drive motor 13 capable of forward and reverse rotation is provided corresponding to the upper arm 9a, and a pinion 14 fixed to the output shaft 13a of the motor 13 is connected to the rack of the upper arm 9a. It is meshed with 9e. By rotating the drive motor 13 forward and backward, the upper arm 9a is rotated through the engagement between the pinion 14 and the rack 9e.
is moved back and forth, and the operating ring 7 is reciprocated back and forth along the outer periphery of the shroud 2 to change the shape of the shroud 2.

That is, when the front resistance of the axial flow fan 4 is low, such as when the axial flow fan 4 is running, the taper of the open portion 11 is made relatively small, that is, the front opening angle θl is made relatively small. In order to do this, as shown in FIG.
It is arranged at a predetermined distance backward from the position. On the other hand, the axial fan 4 during idling etc.
In the case of high pressure loss (high ventilation system) where the frontal resistance is large, the second
As shown in the figure, the operating ring 7 is moved closer to the shroud 2, and the position of the border 2c is adjusted to the front edge 4 of the axial fan 4.
It is designed to be placed close to a.

In this embodiment, the shape of the shroud 2 is automatically changed and controlled in response to the difference in ventilation system conditions between running, which is a low ventilation system, and idling, which is a high ventilation system. There is. That is, the drive motor 13 is driven and controlled based on control (No. 8) from a controller (not shown). This controller outputs a control signal to the drive motor 13 based on a detection signal from a vehicle speed sensor (not shown). In the idling state, which is zero, the operating ring 7 is located at the forward position (original position) shown in FIG.
When the vehicle starts running and reaches a predetermined speed or higher, the controller outputs a control signal to the drive motor 13 to cause it to rotate forward by a predetermined amount in order to position the actuating ring 7 in the center position shown in FIG.

Further, when the running vehicle stops and returns to the idling state, the controller outputs a control signal to the drive motor 13 to return the operating ring 7 to the forward position shown in FIG. let

In this embodiment, the setting of the movement amount of the actuating ring 7 corresponding to the ventilation system conditions, that is, the position setting for changing the boundary 2C of the shroud 2, was determined in advance through experiments, and the explanation will be given in Sections 6 to 6. Perform the following according to Figure 9.

FIG. 9 shows distances LL, L2, L3, . L4
．． Shows the noise level for the size of L5, when in a high ventilation system,
Measurement results corresponding to each condition under medium ventilation and light conditions are shown. Each of the distances L1 to L5 is a different distance corresponding to the amount of movement of the actuating ring 7, as shown in FIGS. 6 to 8, and as shown in FIG. at a predetermined interval (10 in this example) up to L5.
This is the value decreased by mm). In addition, in order to set each ventilation system condition, a certain amount of air (1000 m3/hour in this example) is blown from the front of the radiator 1, and then the number of wire meshes that shield the front side of the radiator 1 is increased or decreased. .

As is clear from FIG. 9, it can be seen that the distance LL-L5 that provides the best noise level differs depending on the ventilation system conditions. That is, in a high ventilation system, the noise level is highest at the maximum distance L1 (approximately 65 dB), and the lowest at the minimum distance L5 (approximately 62 dB).
I understand that.

Also, in the medium ventilation and light conditions, the difference in noise level is small over each distance L1 to L5, but at distance L3. Low at L4 (
It can be seen that there is a tendency of approximately 59 dB). Furthermore, in the case of a low ventilation system, it can be seen that the noise level is the highest at the minimum distance L5 (approximately 58 dB), and the lowest at the distance L2, which is close to the maximum (approximately 56 dB).

Therefore, based on these measurement results, the relationship between the lowest noise level and each distance L1 to L5 for each ventilation condition, that is, the optimum level, is shown in FIG. 9 by a chain line.

As is clear from this optimum level, it is desirable that the distance from the front edge 4a of the axial fan 4 to the boundary 2C of the shroud 2 be large in the case of a low ventilation system, and It can be seen that it is desirable to keep the value small in terms of system time.

In this embodiment, as shown in FIG. 10, in consideration of the longitudinal body size W of the axial fan 4 (4Q mm in this case), in the case of a low ventilation system, the shroud 2 is The distance to the boundary 2C is set to be half the size of the physique W (20 mm in this case). Also, the front opening angle θ1 of the open part 11 at this time is 35
The angle is set to be as small as 1°. on the other hand,
In high ventilation systems, the distance is set to zero. Also, at this time, the front opening angle θ1 of the open portion 11 is set to a large angle of about 70°, and the rear opening angle θ2 of the air conducting portion 10 is set to a large angle of about 70°.
The angle is set to approximately a.

Next, the operation of the blower configured as described above will be explained.

First, during idling, which is a high ventilation system, while the axial component airflow passing through the shroud 2 decreases, the radial and circumferential component flows remain unchanged.

At this time, the actuating ring 7 is placed at the front position, which is the original position shown in FIG. The taper of the open portion 11, that is, the front opening angle θ1 is large.

Therefore, less air flows from the blade tip of the axial fan 4 to the air conduction part 10 along the slope of the open part 11, and air is generated at the blade tip of the axial fan 4 at the leading edge of the air conduction part 10. Turbulence is removed and noise generation can be reduced.

In addition, in this state, a rear opening angle θ2 is formed on the outlet 2b side of the air conducting portion 10, and the outlet 2b side is in a state of expanding rearward, so that there is no possibility that the air may collide with the vicinity of the outlet 2b of the air conducting portion 10. Since the centrifugal flow is removed, the generation of noise on the outlet 2b side can be reduced.

Furthermore, by removing turbulent flow and centrifugal flow in the air conduction section 10 as described above, loss in air blowing can be reduced, so that the cooling efficiency of the radiator 1 can be improved.

On the other hand, when the vehicle starts running and becomes a low ventilation system, the axial component airflow passing through the shroud 2 increases. Then, when the vehicle speed exceeds a predetermined value, the drive motor 13
is actuated, the actuating ring 7 is switched to the central position shown in FIG. The taper of the open portion 11, that is, the front opening angle θ1 is relatively small.

Therefore, the flow of air that flows obliquely along the slope of the open part 11 and passes through the axial fan 4 is directed toward the centripetal direction of the axial fan 4, and turbulence occurs at the blade tips of the axial fan 4. can be made smaller, and the axial component airflow passing through the shroud 2 can be made stronger. As a result,
Air outflow from the air conduction portion 10 becomes smoother, and the generation of noise can be reduced, and the cooling efficiency of the radiator 1 can be improved.

When the vehicle stops and returns to the idling state, the drive motor 13 is activated and the operating ring 7 is returned to the forward position shown in FIG. becomes smaller again.

[Second Embodiment] Next, a second embodiment embodying the present invention will be described with reference to FIGS. 11 to 14. In this embodiment, the same members as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted, and only the different points will be explained.

In this embodiment, as shown in FIGS. 11 and 12, the shroud 2 is constituted by a tapered open part 16 and a cylindrical air conducting part 17, which are formed separately.

The open portion 16 is formed by leaving an opening edge 16a corresponding to the inlet 2a of the shroud 2, and the other portions are divided into a plurality of strips 16b extending in the radial direction. As shown in FIG. 13, each strip 16b are respectively bendable about the opening edge 16a as a fulcrum.

Further, the open portion 16 has a double structure consisting of an outer hard layer 18 and a rubber layer 19 attached to the inner side. and,
Based on the tension of the rubber layer 19, each strip 16b
As shown by the solid line in the figure, it is held in an inwardly bent state, that is, in a state in which the front opening angle θ1 is relatively large. Therefore, in order to make the front opening angle θ1 relatively small, when the strips 16b are bent outward as shown by the two-dot chain line in FIG.
It will be bent against the tension of.

The air conduction portion 17 is formed by dividing into a plurality of front strips 17b extending in the axial direction at the front side, leaving the middle section 17a, and similarly, the rear section is divided into a plurality of rear strips 17c extending in the axial direction. It is formed by dividing. Moreover, as shown in FIG. 14, each strip piece 17b, 17c
Each can be bent using a as a fulcrum. Unlike the open part 16, the air conduction part 17 has an outer rubber layer 19,
It has a double structure with an inner hard layer 18. and,
Based on the tension of the rubber layer 19, each strip piece 17b, 17c
is adapted to maintain an outwardly bent state as shown by the solid line in FIG. That is, in the rear strip 17C, the rear opening angle θ2 is maintained in a large state.

Therefore, when each of the strips 17b and 17c is bent inward as shown by the two-dot chain line in FIG.
b, 17C is bent against the tension of the rubber layer 19. In this inwardly bent state, the rear strip 17c has a smaller rear opening angle θ2 (in this case, θ°).
It is bent into a bent position.

Of the open portion 16 and air conduction portion 17 thus formed, the front strip 17b of the air conduction portion 17 is engaged with and assembled inside the open portion 16 to form the shroud 2.

An actuation ring 20 serving as an actuation member is provided on the outer periphery of the air conducting portion 17 so as to be able to reciprocate and slide in the front and rear directions, and a rack 20a is formed above the actuation ring 20.

Further, the output shaft 13 of the drive motor 13 is connected to this rank 20a.
A pinion 14 fixed to a is engaged with the pinion. When the drive motor 13 is rotated forward and backward, the operating ring 20 is rotated through the engagement between the pinion 14 and the rack 20a.
is reciprocated back and forth along the outer periphery of the shroud 2 to change the shape of the shroud 2.

That is, in this embodiment, in order to make the taper of the opening part 16, that is, the front opening angle θ1, relatively small in a low ventilation system where the frontal resistance is small such as when driving, the actuation ring 20 is adjusted as shown in FIG. is moved closer to the center of shroud 2. As a result, the front strip 17b of the air conduction section 17
The actuating ring 20 is separated from the front strip 17b, and the front strip 17b is bent outward by the tension of the rubber 1!19. At the same time, the actuation ring 20 engages with a part of the rear strip 17c,
The rear strip 17c is forcibly bent inward against the tension of the rubber layer 19. Therefore, the air conduction portion 17 and the open portion 16
The boundary 2C is spaced a predetermined distance rearward from the front edge 4a of the axial fan 4. Further, the air conducting portion 17 has a cylindrical shape with an equal inner diameter from the intermediate portion 17a to the outlet 2b side. In other words, the rear opening angle θ2 of the air conducting portion 17 is 06.

On the other hand, in a high ventilation system where the front resistance is large such as during idling, the taper of the opening part 16, that is, the front opening angle θ1
In order to make it relatively large, the actuating ring 20 is moved toward the front center of the shroud 2, as shown in FIG. As a result, the actuating ring 20 separates from the rear strip 17C of the air conducting portion 17, and the rear strip 17c is bent outward by the tension of the rubber layer 19. At the same time, the front strip 1
The actuation ring 20 engages with a part of the front strip 17b.
is forcibly bent inward against the tension of the rubber layer 19. Therefore, the position of the boundary 2C is the front edge 4 of the axial fan 4.
located close to a. In addition, the outlet 2 of the air conduction section 17
The b side tapers to the rear. In other words, the rear opening angle θ2 of the air conducting portion 17 becomes a predetermined angle.

In this embodiment, in order to automatically change and control the shape of the shroud 2 in response to the difference in ventilation system conditions between running, which is a low ventilation system, and idling, which is a high ventilation system, As in the first embodiment, the drive motor 13 is controlled based on the vehicle speed.

Next, the operation of the blower configured as described above will be explained.

First, during idling, which is a high ventilation system, the operating ring 20 is placed in a forward position as shown in FIG.
The boundary 2C between the air conduction part 17 and the open part 16 is located close to the front edge 4a of the axial fan 4, and the taper of the open part 16, that is, the front opening angle θ1 is large.

Therefore, less air flows from the blade tip of the axial fan 4 to the air conduction part 17 along the slope of the open part 16, and air is generated at the blade tip of the axial fan 4 at the leading edge of the air conduction part 17. Turbulence is removed and noise generation can be reduced.

In addition, in this state, a rear opening angle θ2 is formed on the outlet 2b side of the air conducting portion 10, and the outlet 2b side is in a state of expanding rearward, so that the air conducting portion 17 may collide with the vicinity of the outlet 2b. Since the centrifugal flow is removed, the generation of noise on the outlet 2b side can be reduced.

Furthermore, by removing turbulent flow and centrifugal flow in the air conduction section 17 as described above, loss in air blowing can be reduced, so that the cooling efficiency of the radiator 1 can be improved.

On the other hand, when the vehicle starts running and enters the low ventilation system, the drive motor 13 is activated and the operating ring 20 is switched to the central position shown in FIG. 2c is arranged at a predetermined distance from the front edge 4a of the axial fan 4, so that the taper of the open portion 16, that is, the front opening angle θ1 is relatively small, and the rear opening angle θ2 of the air conducting portion 17 is O''.

Therefore, the flow of air that flows obliquely along the slope of the open part 16 and passes through the axial fan 4 is directed toward the centripetal direction of the axial fan 4, and turbulence occurs at the blade tips of the axial fan 4. can be made smaller, and the axial component airflow passing through the shroud 2 can be made stronger. As a result,
Air outflow from the air conduction portion I7 becomes smooth, and the generation of noise can be reduced, and the cooling efficiency of the radiator 1 can be improved.

When the vehicle stops and returns to the idling state, the drive motor 13 is activated and the operating ring 20 is returned to the forward position shown in FIG.
6, that is, the front opening angle θ1 becomes small again.

As described above, in the blower of each of the embodiments described above, the shape of the shroud 2 can be changed as appropriate depending on the ventilation system conditions such as when the vehicle is idling or running. That is, when the vehicle is in a high-airflow system such as when idling, the shroud 2 can be changed to a low-noise type, and when the vehicle is running in a low-airflow system, the shroud 2 can be changed to a low-noise type with a high cooling efficiency. Can be changed.

Therefore, in the blower of each of the embodiments described above, unlike the conventional blower having a fixed shape, the noise of the blower can be constantly reduced regardless of the driving condition of the vehicle, and the cooling efficiency of the radiator 1 can be improved. Can be done.

The present invention is not limited to the above-mentioned embodiments, and may be implemented as follows by appropriately changing a part of the structure without departing from the spirit of the invention.

(1) In each of the above embodiments, in order to change the shape of the shroud 2 according to the ventilation system conditions, the drive motor 13 is configured to be driven and controlled based on the vehicle speed. A pressure sensor for measuring wind pressure is attached to each, and the ventilation system conditions such as high ventilation system or low ventilation system are determined based on the difference in the detection values of the meat pressure sensors, and the drive motor 13 is driven based on the condition determination. It may be configured to control. Alternatively, the drive motor 13 may be driven and controlled simply by operating a changeover switch provided at the driver's seat.

(2) In each of the above embodiments, a predetermined rear opening angle θ2 is provided so that the outlet 2b side of the shroud 2 widens rearward, but in other words, the rear opening angle θ2 is always set to θ '' may be configured.

(3) In each of the embodiments described above, the motor 3 is provided as a drive source for rotating the axial fan 4, but a vehicle engine may be used as the drive source.

[Effects of the Invention] As detailed above, according to the present invention, the shape of the shroud can be appropriately changed according to differences in ventilation system conditions such as during high pressure loss or low pressure loss, thereby achieving noise reduction. In addition, it exhibits an excellent effect of being able to improve cooling efficiency.

[Brief explanation of the drawing]

Figures 1 to 10 are drawings showing a first embodiment embodying the present invention, in which Figure 1 is a side sectional view showing the blower in a state adjusted to low pressure 1-person operation, and Figure 2 is a high pressure loss 3 is a front view of the blower, FIG. 4 is a partially cutaway side view showing the original form of the shroud, FIG. 5 is a perspective view of the actuation ring, and FIGS. Figure 8 is a partially cutaway side view illustrating the relationship between the moving position of the actuating ring and the shape of the shroud, and Figure 9 is a graph showing the relationship between the distance from the leading edge of the axial fan to the leading edge of the air conducting part and the noise level. , FIG. 1O is a partially cutaway side view explaining the shape setting of the shroud, FIGS. 11 to 14 are drawings showing a second embodiment embodying the present invention, and FIG. FIG. 12 is a partially cutaway side view showing the blower in a state where it is adjusted to high pressure loss. FIG. 13 is a partially cutaway side view showing the double structure of the open part.
Fig. 4 is a partially cutaway side view showing the double structure of the air conducting part, Fig. 15 is a partially cutaway side view illustrating the effect of a conventional blower at low pressure loss, and Fig. 16 is a partially cutaway side view showing the effect at high pressure loss. FIG. 17 is a partially cutaway side view for explaining the operation of the blower that can cope with high pressure loss. In the figure, 2 is a shroud, 2C is a boundary, 3 is a motor as a driving source, 4 is an axial fan, 4a is a front edge, 7.20 is an operating ring as an operating member, 10° 17 is an air conduction part,
11.16 is the open part, 13 is the drive motor, L is the distance, θ
1 is the front opening angle, and θ2 is the rear opening angle.

Claims (1)

[Claims] 1. The shroud includes a shroud through which air flows and is composed of an air conduction portion having a cylindrical shape and an open portion that is continuously opened in a tapered shape from the air conduction portion toward the upstream side with respect to the air flow, and the air conduction In a vehicle blower equipped with an axial fan that is enclosed and fixed in a shroud and rotated by a drive source, the boundary between the air conduction part and the open part is on the upstream or downstream side with respect to the air flow of the shroud. An actuating member is provided for moving the opening to at least one side, and the actuating member moves the boundary position to the above in order to make the taper of the opening relatively small when the upstream resistance of the axial fan is low and the pressure drop is low. The axial fan is disposed at a predetermined distance downstream from the front edge of the axial fan, and the border position is set to the axial fan in order to make the taper of the opening relatively large during high pressure loss when the upstream resistance of the axial fan is large. A vehicle blower characterized by being placed close to the front edge of the fan.