JP2010229902A - Engine blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine blower, in which the stiffness of a blow molded frame is partially increased to reduce the resonance vibration level of the frame, shift a resonance frequency of the frame, making it hard-to-resonate, and to suppress weight increase. <P>SOLUTION: In the engine blower, the frame 2 is blow-molded to have hollow parts 23A, 23B, and formed resin 24 is filled in the hollow parts 23A, 23B. Consequently, as the hollow parts 23A, 23B of the frame 2 is filled with the formed resin 24 and is close to a solid structure, the stiffness of the frame 2 (spring constant) is made higher as compared to frames which are not filled with formed resin 24. Namely, the resonance frequency of the frame 2 is shifted, the frame does not easily resonate with the engine, and the resonance vibration level of the frame 2 generated by vibration of the engine is reduced, by increasing the stiffness. Further, the weight increase of the frame 2 is minimized by filling formed resin 24. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine blower.

Conventionally, for example, an engine blower of a backpack type has main components such as an engine, a centrifugal blower, and a fuel tank mounted on a frame having an L shape in side view formed by blow molding having good absorbability of a drop impact. The operator carries the work of blowing grass, dead leaves, etc. on the back of the frame (for example, Patent Document 1).
JP 2008-2310 A

  However, the L-shaped bent portion of the blow-molded frame has a lower rigidity than the bent portion of the injection-molded frame having a rib structure, for example, because of the hollow structure. There was a problem that the level was increased and the worker was uncomfortable.

  As a method for increasing the rigidity of the L-shaped bent portion of the blow-molded frame, it is conceivable to increase the weight of the parison, which is a material, to increase the wall thickness. However, even if the wall thickness of the parison is increased, it is difficult to increase only the thickness of the bent portion due to the nature of blow molding, so the overall thickness of the frame increases and the weight of the frame increases. End up.

  The object of the present invention is to partially increase the rigidity of the blow molded frame, thereby reducing the vibration level of the resonance of the frame, making it difficult to resonate by shifting the resonance frequency of the frame, and suppressing an increase in weight. To provide an engine blower.

  An engine blower according to the present invention includes an engine, a fan driven by the engine, a blower body configured to include a volute case in which the fan is housed, a wind pipe connected to the blower body, A frame for supporting the blower body, the frame being formed by blow molding, having a hollow portion therein, and the hollow portion being filled with foamed resin. And

  In the engine blower according to the present invention, the frame has an L shape having a back support portion that comes into contact with a user's back and a pedestal portion extending in a direction orthogonal to the back support portion, and the foam The resin is filled only in the hollow portion corresponding to the L-shaped bent portion.

  The engine blower according to the present invention is characterized in that the hollow portion is provided across the backrest portion and the pedestal portion.

  In the engine blower according to the present invention, the foamed resin is urethane foam.

  According to the present invention, since the hollow portion of the frame is close to a solid structure filled with the foamed resin, the rigidity (spring constant) of the frame can be increased as compared with the case where the foamed resin is not injected. In other words, by increasing the rigidity, the resonance frequency of the frame is shifted and it is difficult to resonate with the engine, and the vibration level of the resonance of the frame caused by the vibration of the engine can be reduced. Further, the increase in the weight of the frame can be suppressed as compared with the injection molding in which the frame material itself is a solid structure.

When the foamed resin is filled only in the hollow portion corresponding to the bent portion of the L-shape, the extra filling of the foamed resin can be eliminated, and the increase in the weight of the frame can be minimized.
In the case where the hollow portion filled with the foamed resin is formed across the backrest portion and the pedestal portion, the foamed resin can be filled into the bent portion of the frame at once, and the filling operation can be facilitated.
By using urethane foam as the foamed resin, the expansion ratio of urethane foam can be easily adjusted, and the rigidity of the frame can be reliably increased to a target size.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of the engine blower 1 viewed from the back side (back side with respect to the worker), and FIG. 2 is a perspective view of the engine blower 1 viewed from the front side (front side with respect to the worker). 3 is a rear view showing the frame 2, and FIG. 4 is a cross-sectional view of the frame 2 taken along line IV-IV in FIG.
As shown in FIGS. 1 and 2, the engine blower 1 includes a frame 2, a blower body 3 supported by the frame 2, and a wind pipe (not shown) connected to the blower body 3.

  As shown in FIG. 4, the frame 2 includes a backrest portion 21 to which a shoulder belt is attached and abuts against a user's back, and a pedestal portion 22 extending in a direction orthogonal to the backrest portion 21. It is formed in an L shape in side view. As shown in FIG. 2, the operation handle 4 is rotatably attached to the side of the backrest portion 21. During operation, the operation handle 4 is tilted to the front side (left side in FIG. 2) and the operation handle 4 is operated to adjust the output of the engine 31 of the blower body 3.

  The blower body 3 is attached to the engine 31, a fan (not shown) driven by the engine 31, a volute case 32 that accommodates the fan, a fuel tank 33, fuel from the fuel tank 33, and intake air. Is provided with a carburetor 34 that generates an air-fuel mixture and a muffler 35 that silences the sound of the engine 31 and discharges exhaust gas to the outside.

  The blower body 3 is supported by the gantry 22 via left and right vibration isolating rubbers 36A and 36B provided at the lower part of the volute case 32, and via a vibration isolating rubber (not shown) provided at the upper part of the volute case 32. By being connected to the back support portion 21, the frame 2 is supported at three points. In such a blower body 3, when the fan is driven by the engine 31 and the pumped air is generated by the fan, the pumped air is sent from the volute case 32 to the wind pipe connected to the volute case 32. Will be ejected from.

The following is a detailed description of the characteristic configuration of the engine blower 1 of the present embodiment.
The frame 2 of the present embodiment is formed by blow molding and includes a plurality of hollow portions 23. Of the hollow portion 23, the left and right hollow portions 23 </ b> A and 23 </ b> B formed in a portion straddling the backrest portion 21 and the pedestal portion 22 are filled with a foamed resin 24.

  As the foamed resin 24, in the present embodiment, foamed urethane whose foaming ratio can be easily adjusted is used, but foamed polystyrene, foamed polypropylene, or the like can be applied. The filling amount of the foamed resin 24 may be an amount that can increase the rigidity of the frame 2 to such an extent that the frame 2 is less likely to resonate. In this embodiment, the product of the foamed resin 24 and the foaming ratio is the hollow portions 23A and 23B. It is a volume that is substantially equal to the volume of. The foamed resin 24 is in close contact with the frame 2 during the foaming process.

  Such foamed resin 24 is filled after blow molding of the frame 2. That is, after blow molding of the frame 2, a filling hole (not shown) that communicates the inside and the outside is provided in a portion corresponding to the hollow portions 23A and 23B of the frame 2, and a filling nozzle is inserted into the filling hole to fill the foamed resin material. The filled foamed resin material is foamed by the foaming agent mixed in the base material and filled as the foamed resin 24.

  In the configuration as described above, since the hollow portions 23A and 23B corresponding to the bent portions of the frame 2 are filled with the foamed resin 24, the bent portions are close to a solid structure and the foamed resin 24 is not injected. Compared to the case, the rigidity (spring constant) of the bent portion can be increased. That is, by increasing the rigidity, the resonance frequency of the frame 2 can be shifted to make it difficult to resonate with the engine 31, and the vibration level of the resonance of the frame 2 generated by the vibration of the engine can be reduced. Further, since the foamed resin 24 is injected only into the bent portion and the foamed resin is light in weight with respect to the volume, an increase in the weight of the frame 2 can be minimized.

Next, experimental results related to the vibration of the frame 2 are shown below.
FIG. 5 is a diagram showing the rigidity (spring constant) of the frame 2 showing the effect of the present embodiment. The rigidity of the frame 2 is measured by fixing the backrest portion 21 of the frame 2, applying a downward load to the distal end portion of the pedestal portion 22, and measuring the amount of displacement of the distal end portion of the pedestal portion 22 toward the bottom surface. Was measured. FIG. 5 shows that the rigidity (spring constant) of the frame 2 is increased by filling the foamed resin 24.

And FIG. 6 is a figure which shows the vibration level of the flame | frame for every engine speed which shows the effect of this embodiment. From FIG. 6, it was confirmed that when the rigidity of the frame 2 increases, the vibration level of the frame 2 decreases. In particular, it can be seen that the vibration level in the rotational speed range A (3600 to 3800 [rpm]) frequently used during work is reliably reduced. This is considered to be due to the resonance frequency of the frame 2 being shifted due to the improved rigidity.
[Modification of Embodiment]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the frame 2 of the present embodiment has an L-shape when viewed from the side, but the frame of the present invention does not have to be an L-shape, and may be any shape that can support the blower body 3 on the back. . That is, taking into consideration the support structure in the frame, the overall shape of the frame, and the like, the foamed resin may be filled into the hollow portion that can reliably improve the rigidity and lower the vibration level.

  The present invention can be used for an engine blower used for outdoor cleaning of a park or the like.

The perspective view which looked at the engine blower from the back side (back side with respect to an operator). The perspective view which looked at the engine blower from the front side (front side with respect to an operator). The rear view which shows a flame | frame. Sectional drawing at the time of cut | disconnecting a flame | frame by line IV-IV in FIG. The figure which shows the rigidity (spring constant) of a flame | frame. The figure which shows the vibration level of the flame | frame for every engine speed.

  DESCRIPTION OF SYMBOLS 1 ... Engine blower, 2 ... Frame, 3 ... Blower main body, 21 ... Backrest part, 22 ... Mount part, 23, 23A, 23B ... Hollow part, 24 ... Foam resin, 31 ... Engine, 32 ... Volute case.

Claims (4)

A blower body comprising an engine, a fan driven by the engine, and a volute case in which the fan is housed;
A wind pipe connected to the blower body;
And a frame for supporting the blower body,
The frame is formed by blow molding and has a hollow portion inside,
An engine blower characterized in that the hollow portion is filled with foamed resin. The engine blower according to claim 1, wherein
The frame has an L shape having a back support portion that comes into contact with a user's back and a pedestal portion extending in a direction orthogonal to the back support portion.
The engine blower, wherein the foamed resin is filled only in the hollow portion corresponding to an L-shaped bent portion. The engine blower according to claim 2,
The hollow portion is provided across the backrest portion and the pedestal portion. Engine blower, wherein The engine blower according to any one of claims 1 to 3,
The engine blower, wherein the foamed resin is urethane foam.

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