JP2000145685A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve blowing performance of a centrifugal blower mounted with blades in the cantilevered supporting state. SOLUTION: In a centrifugal blower in which many blades 41, 42 are juxtaposedly arranged supporting in the rotational circumferential direction in the cantilevered supporting state in relation to an impeller side plate 40, the outer end edges 41a, 42a of the blades 41, 42 in the rotational radial direction are so formed in an inclined attitude that the blade free ends on the opposite sides to the supporting sides to the impeller side plate 40 may be closer to the rotational axis p.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a centrifugal blower,
More specifically, a centrifugal blower in which a number of blades are arranged side by side in the rotating circumferential direction in a cantilevered state with respect to the impeller side plate to form an impeller, and a main blade extending from near the rotation axis to the outer peripheral portion of the impeller side plate Are arranged side by side in the rotating circumferential direction in a cantilevered state with respect to the impeller side plate, and auxiliary blades located only on the outer peripheral portion of the impeller side plate are arranged between the main blades in a cantilevered state with respect to the impeller side plate. And a centrifugal blower having an impeller formed therein.

[0002]

2. Description of the Related Art Conventionally, this type of centrifugal blower has a rotating radial direction as shown in FIG. 18 similarly to a centrifugal blower in which each blade is provided between two impeller side plates in a double-supported state. Outer edge 41 of each blade 41, 42 at
a and 42a are edges in a posture parallel to the rotation axis P, and the outer edges 41a and 42a of the respective blades 41 and 42 in the radial direction of rotation of the casing 31 in which the impeller 29 is installed.
The inner circumferential surface 31a of the casing opposing the rotating shaft core 42a
, So that each of the blades 41, 42
Between the outer edges 41a and 42a and the inner peripheral surface 31a of the casing facing the outer edges 41a and 42a.

[0003]

However, this type of centrifugal blower requires only one impeller side plate 40 as compared with a type in which the blades 41 and 42 are supported in a double-supported state, so that manufacturing and cost are reduced. In addition, there is an advantage that the required power can be reduced by reducing the weight of the impeller 29. However, since the blades 41 and 42 are in a cantilever support state,
During rotation of the impeller 29, the impeller side plate 40 and the blades 41 and 42 are bent by centrifugal force and gas resistance, and the free ends of the cantilevered blades 41 and 42 (specifically, the impeller side plate 40
Free ends 41b, 42b on the side opposite to the support side for
18 and the blade outer edges 41a and 42a in the rotational radius direction) are displaced so as to protrude from the outer periphery of the impeller side plate 40 as shown by a one-dot chain line in FIG. The blades 41, 42 when rotating
However, there is a danger that the contact with the inner peripheral surface 31a of the casing may cause breakage. In order to avoid such contact, there has been a problem that the rotational speed used is limited to a low value and the blowing performance is limited.

In addition, even if the clearance does not come into contact with the casing inner peripheral surface 31a, the clearance between the outer edges 41a, 42a of the blades 41, 42 in the rotational radial direction and the casing inner peripheral surface 31a opposed thereto is reduced. The displacement of the free end of the blade as described above makes the blade unsuitable, and there is also a problem that the blowing performance is reduced due to this.

[0005] In view of this situation, the main problems of the present invention are:
The problem is to solve the above problem by rational improvement while taking advantage of the form of providing the blade in a cantilevered support state.

[0006]

Means for Solving the Problems [1] In the invention according to the first aspect, in a configuration in which a large number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate, a rotating blade is formed. The outer edge of the blade in the radial direction is formed so as to be inclined toward the rotation axis closer to the blade free end side opposite to the support side with respect to the impeller side plate.

[0007] According to this configuration, it is anticipated that the impeller side plate and the blade itself bend due to centrifugal force and gas resistance during the rotation of the impeller and the free end of the blade is displaced. Since the edge is set as an initial attitude at the time of non-rotation, the outer edge of the blade in the radial direction of rotation is simply formed in a posture parallel to the axis of the rotation because the blade is inclined toward the rotation axis closer to the free end of the blade. Compared to the conventional structure
It is possible to more reliably prevent the blade from contacting the inner peripheral surface of the casing due to the displacement as described above, so that the rotational speed of the impeller can be increased as compared with the conventional structure.

In addition, the clearance between the outer edge of the blade in the radial direction of rotation and the inner peripheral surface of the casing facing the blade is inversely optimized by the displacement of the free end of the blade due to the rotation. Therefore, the blowing performance of this type of centrifugal blower can be effectively improved.

[2] In the invention according to claim 2, a large number of the main blades extending from near the rotation axis center to the outer peripheral portion of the impeller side plate are formed.
Along with being arranged side by side in the rotational circumferential direction in a cantilevered state with respect to the impeller side plate, auxiliary blades located only on the outer peripheral portion of the impeller side plate are placed between the main blades in a cantilevered state with respect to the impeller side plate. In the configuration in which the impeller is formed, the outer edge of the auxiliary blade in the rotational radial direction is inclined toward the rotation axis closer to the blade free end side opposite to the support side with respect to the impeller side plate. Form.

That is, the auxiliary blade provided on the outer peripheral portion of the impeller side plate between the main blades has a function of improving the centrifugal acceleration performance of the entire blade group and improving the blowing ability while keeping the suction resistance small. However, since the auxiliary blade is located only on the outer peripheral portion of the impeller side plate (that is, the length of the blade in the radial direction of rotation is shorter than the main blade extending from near the rotation axis to the outer peripheral portion of the impeller side plate). However, the blade is more likely to bend than the main blade, and the free end of the blade is likely to be displaced from the outer periphery of the impeller side plate, so that the rotation speed used to avoid contact of the auxiliary blade with the inner peripheral surface of the casing is increased. It is easy to be restricted low,
Even without contact, the clearance between the outer edge of the auxiliary blade in the radial direction of rotation and the inner circumferential surface of the casing facing the outer edge is likely to be inappropriate, and the blowing performance is likely to be reduced.

On the other hand, according to the above configuration, the outer edge of the auxiliary blade in the radial direction of rotation is set to the initial posture when not rotating, in anticipation that the free end of the auxiliary blade is largely displaced by rotation. As the free end side of the auxiliary blade is inclined toward the rotation axis closer to the free end side, compared to a conventional structure in which the outer edge of the auxiliary blade in the rotational radius direction is simply formed in a position parallel to the rotation axis. Such a situation that the auxiliary blades come into contact with the inner peripheral surface of the casing due to the displacement as described above can be more reliably avoided, so that the rotational speed of the impeller can be increased as compared with the conventional structure.

[0012] Further, there is provided an operation mode in which the clearance between the outer edge of the auxiliary blade in the radial direction of rotation and the inner peripheral surface of the casing opposite thereto is appropriately adjusted by the displacement of the free end of the auxiliary blade due to rotation. from these things,
The air blowing performance of this type of centrifugal blower can be effectively improved in combination with the improvement of the air blowing performance due to the provision of the auxiliary blades.

[3] According to a third aspect of the present invention, in the embodiment of the second aspect of the present invention, the outer edges of the auxiliary blade and the main blade in the rotational radial direction are supported by the impeller side plate. And the inclination angle of the outer edge in the rotational radius direction of the auxiliary blade is set to the outer end in the rotational radius direction of the main blade. Make it larger than the edge inclination angle.

According to this configuration, the free end of the main blade is displaced by the rotation, and the clearance between the outer edge in the rotation radial direction of the main blade and the inner peripheral surface of the casing facing the outer edge becomes inappropriate. Can also be prevented.

Further, as described above, the auxiliary blade is more flexible than the main blade, but the inclination angle of the outer edge in the rotational radius direction of the auxiliary blade is determined by changing the inclination angle of the outer edge in the rotational radius direction of the main blade. By making it larger than the inclination angle, with the displacement of the free end of each blade due to rotation,
The clearance for the auxiliary blade and the clearance for the main blade can be made equivalent, thereby causing the clearance for the auxiliary blade and the clearance for the main blade to be different from each other. In a state where the generation of vibration and noise due to the pulsating pressure change is effectively suppressed, the improvement of the ventilation performance can be more effectively achieved by optimizing the clearance for each blade.

[4] In the invention according to claim 4, a large number of the main blades extending from near the rotation axis to the outer peripheral portion of the impeller side plate are formed.
Along with being arranged side by side in the rotational circumferential direction in a cantilevered state with respect to the impeller side plate, auxiliary blades located only on the outer peripheral portion of the impeller side plate are placed between the main blades in a cantilevered state with respect to the impeller side plate. In the configuration in which the impeller is formed to be provided in a cantilevered state with respect to the impeller side plate, and in a state in which a protrusion dimension in the rotation axis center direction from the impeller side plate is smaller than the auxiliary blade, the rotational radial direction And a blade extension rib extending from the inner edge of the auxiliary blade toward the rotation axis.

According to this structure, the auxiliary blade is easily bent by the rotation, but the bending of the auxiliary blade itself and the bending of the impeller side plate are suppressed by the blade extending rib, so that the free end portion of the auxiliary blade becomes the blade. It is possible to effectively prevent displacement to a state of protruding from the outer periphery of the vehicle side plate, thereby more reliably avoiding a situation in which the auxiliary blade comes into contact with the inner peripheral surface of the casing. And the clearance between the outer edge of the auxiliary blade in the radial direction of rotation and the inner peripheral surface of the casing opposed thereto can be stably maintained in an appropriate state.

Further, the above-mentioned blade extending ribs extend from the inner edge of the auxiliary blade in the rotational radius direction toward the rotation axis side, but have a protrusion dimension from the impeller side plate in the rotation axis direction. Since the auxiliary blade is smaller than the auxiliary blade, it is possible to avoid an increase in suction resistance due to the provision of the blade extension rib, and the function of the auxiliary blade to enhance the centrifugal acceleration performance of the entire blade group while maintaining a low suction resistance. It can be maintained, and from these, the blowing performance of this type of centrifugal blower can be effectively improved.

[5] In the invention according to claim 5, in the configuration in which a number of blades are arranged side by side in the rotating circumferential direction in a cantilevered support state with respect to the impeller side plate, a casing in which the impeller is provided is provided. The inner peripheral surface of the casing facing the outer edge of the blade in the radial direction of rotation is inclined such that the free side of the blade, which is opposite to the support side of the blade with respect to the impeller side plate, is further away from the rotation axis. Form.

According to this configuration, it is anticipated that the impeller side plate or the blade itself is bent by the centrifugal force or the gas resistance during the rotation of the impeller and the free end of the blade is displaced. Since the inner peripheral surface of the casing facing the edge is inclined away from the axis of rotation toward the free end of the blade, the conventional structure in which the inner peripheral surface of the casing is simply formed in an attitude parallel to the axis of rotation is used. In comparison, it is possible to more reliably avoid a situation in which the blade comes into contact with the inner peripheral surface of the casing due to the displacement as described above, and thus, it is possible to increase the operating rotational speed of the impeller as compared with the conventional structure.

In addition, the operation mode is such that the clearance between the outer edge of the blade in the radial direction of rotation and the inner peripheral surface of the casing opposed thereto is appropriately optimized by the displacement of the free end of the blade due to the rotation. Therefore, similarly to the above-described invention according to claim 1, the blowing performance of this type of centrifugal blower can be effectively improved.

[6] In the invention according to claim 6, in the configuration in which a large number of blades are arranged side by side in the circumferential direction of rotation in a cantilever support state with respect to the impeller side plate, the plate thickness of the impeller side plate is provided. Is increased toward the rotation axis.

According to this configuration, the deflection of the impeller side plate provided with the cantilevered blades due to the centrifugal force is suppressed by the above-described plate thickness setting of the impeller side plate itself, so that the free end of the blade becomes the blade. It is possible to effectively prevent displacement to a state of protruding from the outer periphery of the vehicle side plate, whereby it is possible to more reliably avoid a situation where the blade contacts the inner peripheral surface of the casing, and to increase the rotational speed of the impeller. In addition, the clearance between the outer edge of the blade in the radial direction of rotation and the inner peripheral surface of the casing facing the same can be more stably maintained in an appropriate state. The blowing performance of the centrifugal blower can be effectively improved.

[7] In the invention according to claim 7, in the configuration in which a large number of blades are arranged side by side in the circumferential direction of rotation in a cantilever support state with respect to the impeller side plate, the impeller side plate is A plurality of ridge ribs are provided radially extending from the vicinity of the shaft center to the outer peripheral portion of the impeller side plate in the rotation radial direction as viewed in the rotation shaft center direction.

According to this configuration, the deflection due to the centrifugal force of the impeller side plate provided with the cantilever-supported blades is suppressed by the plurality of radially arranged ribs as described above, and the free end of the blade becomes the blade. It is possible to effectively prevent the vehicle from being displaced so as to protrude from the outer periphery of the vehicle side plate, thereby more reliably avoiding a situation in which the blade contacts the inner peripheral surface of the casing, similarly to the invention according to claim 6 described above. To increase the operating speed of the impeller, and to maintain a stable clearance between the outer edge of the blade in the radial direction of rotation and the inner peripheral surface of the casing in an appropriate state. Therefore, the blowing performance of this type of centrifugal blower can be effectively improved.

[8] In the invention according to claim 8, in the configuration in which a number of blades are arranged side by side in the circumferential direction of rotation in a cantilevered state with respect to the impeller side plate, the impeller of the impeller with respect to the rotating shaft is formed. A boss portion, an inner cylinder portion fitted externally to the rotation shaft, an outer cylinder portion as a connection base for the blades and the impeller side plate, and one end of the inner cylinder portion and the outer cylinder portion in a rotation axis center direction. The inner tubular portion and the outer tubular portion are formed in such a manner that the annular bottom plate portion is formed on the same surface or substantially the same surface as the impeller side plate to be formed with the annular bottom plate portion extending between the portions. With respect to the annular bottom plate portion, the structure is such that it is located on the same side as the side where the blades are connected to the impeller side plate.

According to this configuration, for example, contrary to the above structure, the other end of the inner cylinder and the outer cylinder (that is, the end of the boss on the side where the cavity between the two cylinders opens) is formed. A structure in which the annular bottom plate is arranged at a position separated from the impeller side plate on the same side as the side where the blades are connected to the impeller side plate in the direction of the rotation axis, in a state corresponding to the impeller side plate in the rotation axis center direction. In comparison with the above, the presence of the annular bottom plate located on the same plane or substantially the same plane as the impeller side plate causes the impeller side plate to bend due to centrifugal force (that is, the back surface of the impeller side plate caused by the cantilevered blade). (Bending to the side), the rigidity of the connection base side can be increased.

By this, the deflection of the impeller side plate provided with the cantilevered blades due to centrifugal force is suppressed, and the free end of the blade is displaced so as to protrude from the outer periphery of the impeller side plate. It is possible to effectively prevent the occurrence of such a situation that the blade contacts the inner peripheral surface of the casing, as in the case of the above-described inventions. Can be enhanced,
In addition, the clearance between the outer edge of the blade in the radial direction of rotation and the inner peripheral surface of the casing opposed thereto can be more stably maintained in an appropriate state. Performance can be effectively improved.

If the impeller side plate and the annular bottom plate are disposed on the same plane or substantially on the same plane and formed as a series of integral members, the rigidity of the connection base side against the deflection of the impeller side plate can be further increased. Thus, it is possible to more effectively suppress deflection of the impeller side plate provided with the cantilevered blades due to centrifugal force.

As described above, according to the invention according to any one of the first to eighth aspects, in the centrifugal blower of the type in which the blades are provided in a cantilever support state, the manufacturing, cost, and cost aspects as described above by cantilever support are provided. It can effectively increase the air blowing performance while taking advantage of the required power, especially for air blowers for fertilizer application equipment (air blowers used for air transport of fertilizer)
For example, it is extremely effective for improving the performance of a blower that requires high-speed rotation or a resin blower that is easily bent.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 shows an overall side view of a rice transplanter with a fertilizer application device. In this rice transplanter, a seedling planting device 3 is connected to a rear portion of a riding type traveling machine 1 via a lifting link mechanism 2 so as to be able to move up and down freely, and a fertilizer device 4 is mounted at a rear portion of the traveling machine 1.

The traveling body 1 has an engine 5 mounted on its front part, a transmission 6 to which power from the engine 5 is transmitted, and a pair of left and right front wheels 7 to which power after shifting via the transmission 6 is transmitted. And a steering wheel 9 for steering the rear wheels 8 and the front wheels 7, and a driver's seat 10.

The seedling planting device 3 includes a feed case 11, a planting transmission case 12, and a rotary type that is pivotally supported on the left and right sides of the rear of the planting transmission case 12 to which the power after shifting via the transmission 6 is transmitted. Planting mechanism 13, seedling table 14 which is reciprocated and laterally moved by a predetermined stroke, and leveling float 15
It is constituted by such as.

As shown in FIGS. 1 to 3, the fertilizer applicator 4
A hopper 16 for storing powdered and granular fertilizer, a feeding mechanism 17 for feeding a predetermined amount of fertilizer in the hopper 16, a groove forming device 18 attached to both left and right portions of the leveling float 15, a feeding mechanism 1
A supply hose 19 for communicating and connecting the 7 with the groove generator 18, a centrifugal blower 20 for feeding fertilizer fed from the feeding mechanism 17 to the groove generator 18 via the supply hose 19, and the traveling machine 1. The hopper 16 is composed of a fertilizer application transmission mechanism 22 and the like that extends from an output shaft 21a of the power distribution mechanism 21 to an input shaft 17a of the feeding mechanism 17.
And a feeding mechanism 17 are disposed at a rear portion of the driving seat 10 in the traveling body 1.

The fertilizer application transmission mechanism 22 includes a power distribution mechanism 21.
, A pair of left and right rotating arms 23 connected to both ends of the output shaft 21a so as to be integrally rotatable in different phases, a single drive shaft 24 spanned over each feeding mechanism 17,
An intermittent clutch mechanism 25 interposed between the drive shaft 24 and each input shaft 17a, and a one-way clutch 26
A pair of left and right swing arms 27 connected via
By converting the rotational motion into a reciprocating oscillating motion by a rod 28 or the like that links the corresponding rotating arm 23 and the oscillating arm 27, only one direction of the reciprocating oscillating motion is transmitted via the one-way clutch 26. Each feeding mechanism 17 is configured to be driven intermittently.

As shown in FIGS. 2 to 5, the centrifugal blower 20 for applying fertilizer includes an impeller 29, an electric motor 30 for rotating the impeller 29, and a casing surrounding the impeller 29 having a spiral shape. 31 and the like, and a discharge port a opened in a tangential direction on a peripheral portion of the casing 31 is horizontally laid across the respective feeding mechanisms 17 so as to be connected to the air guide ports 17b of the respective feeding mechanisms 17. The large diameter air supply pipe 32 is connected to the left end.

That is, the fertilizer applicator 4 is provided with each feeding mechanism 1
7 feeds out a predetermined amount of fertilizer from the hopper 16, puts the fed out fertilizer on the air blown from the centrifugal blower 20, and conveys the air through the supply hoses 19 to the respective groove generators 18. The fertilizer is buried in the fertilizer groove formed in the area.

The air supply pipe 32 extending between the centrifugal blower 20 and each feeding mechanism 17 is configured such that the short pipes 32a in each feeding mechanism 17 and the short pipe 32a at the end and the centrifugal blower 20 are detachable. Rubber connecting hose 3
2b, and can be disassembled by removing the connecting hose 32b at the time of maintenance and inspection.

Reference numeral 17c in FIGS. 2 and 3 denotes a fertilizer supply port formed in each feeding mechanism 17, and a supply hose 19 corresponding to the fertilizer supply port 17c is connected thereto. Reference numeral 33 in FIG.
Reference numeral 9 denotes a cap for closing the fertilizer supply port 17c that is not connected. Reference numeral 17d in FIG. 3 denotes a residual manure discharge port formed in each feeding mechanism 17, and reference numeral 34 denotes a residual manure discharge hose connected to the residual manure discharge port 17d. The fertilizer can be discharged from the residual fertilizer discharge port 17d to the outside via the residual fertilizer discharge hose 34.

The centrifugal blower 20 has its discharge port a connected to the left end of an air supply pipe 32 spanning each of the feeding mechanisms 17 disposed at the rear part of the driving seat 10 in the traveling body 1. Thereby, it is located at the upper left position of the left rear wheel 8 in the rear left portion of the driver's seat 10 which is a position near the control section 1A. Therefore, the centrifugal blower 20 is disposed such that the intake port b formed on one side wall of the casing 31 is located on the rear side, and the casing 31 has an intake duct that turns the intake port b downward. 35 is connected so that the noise of the blower 20 leaking from the intake port b is kept away from the control section 1A.

At the inlet end of the intake duct 35,
A barrier body 36 facing the intake port b is disposed in an inclined position closer to the intake port b toward the rear wheel 8 side, and muddy soil, muddy water, etc., which are flipped up by the rear wheel 8 on the left side by the barrier body 36. Is prevented from entering the intake duct 35.

The barrier 36 is formed by a vertical wall portion 38A of a peripheral member 38 forming a peripheral portion of the intake port b in the intake duct 35.
Attached to. The peripheral member 38 has a peripheral wall 38.
B receives rainwater falling around the intake port b, and causes the received rainwater to flow downward from the side opposite to the intake port b in the vertical wall portion 38A below the barrier body 36, so that during rainy weather work Due to the centrifugal blower 20 taking in rainwater together with the outside air from the intake port b, it is possible to avoid occurrence of fertilization failure such as clogging of fertilizer. Further, the peripheral edge of the barrier body 36 and the peripheral edge member 38
A number of vertically oriented louvers 39 are provided at predetermined intervals in the circumferential direction over the peripheral wall portion 38B, thereby allowing other objects to pass between the intake port b and the barrier body 36 and allow other objects to pass therethrough.
We try to prevent from entering from.

As shown in FIGS. 6 to 8, the centrifugal blower 20
The impeller 29 has a large number of blades 41 and 4 attached to one impeller side plate 40 located on the motor 30 side in the casing 31.
2 is provided in a cantilevered support state, and an open type in which the intake port b side is opened is adopted. Specifically, a large number of curved radial main blades 41 extending from the vicinity of the rotation axis P to the outer circumference are used. The auxiliary blades 42 which are arranged side by side in the rotating circumferential direction in a cantilevered state with respect to the side plate 40 and are similarly provided between the main blades 41 in a cantilevered state with respect to the impeller side plate 40 only in the vicinity of the outer periphery. A wheel 29 is formed.

That is, in the case of the open type, since only one impeller side plate 40 is required as compared with a type in which each blade is spread between two impeller side plates and supported in a double-supported state, the manufacturing surface and This is advantageous in terms of cost, and the required power can be reduced by reducing the weight of the impeller. Further, by providing the auxiliary blades 42 as described above, the number of blades is small at the central portion on the intake side of the impeller 29,
The number of blades increases near the outer peripheral portion where the intake air is centrifugally accelerated. Therefore, the centrifugal acceleration function of the blade group can be enhanced without increasing the intake resistance to improve the blowing performance.

In this embodiment, the impeller side plate 40,
The impeller 29 composed of the main blade 41, the auxiliary blade 42, and the boss portion 44 for the rotary shaft 43 is an integrally molded product made of resin, and the casing 31 has a split structure in the rotary shaft core direction. It is a resin molded product.

The outer edges 41a, 42a of the respective blades 41, 42 in the rotational radius direction are formed by the centrifugal force and the gas resistance during the rotation of the impeller 29 and the impeller side plate 40 and the blade 4
The free ends of the blades 41, 42 are bent (specifically, the blade free end edges 41b, 42b opposite to the support side of the impeller side plate 40 and the blade outer edges 41a, 42a in the rotational radius direction). In the vicinity of the intersection with the impeller), the blade is formed in an inclined position closer to the rotation axis P as the free end of the blade on the side opposite to the support side with respect to the impeller side plate 40 is shifted. Since the auxiliary blade 42 located only on the outer peripheral portion of the impeller side plate 40 has a shorter blade length in the radius of rotation direction than the main blade 41 and is more easily bent, the auxiliary blades 42 are not necessary for forming the inclined edges 41a and 42a as described above. Feather 42
The inclination angle of the outer edge 42a in the rotational radius direction is θ
2 is an outer edge 41 of the main blade 42 in the radial direction of rotation.
a is larger than the inclination angle θ1.

That is, by making the outer edges 41a, 42a of the main blade 41 and the auxiliary blades 42 be inclined edges in this manner, the respective blades 41, 42 caused by the displacement of the free blade end due to the bending described above. Interference with the inner peripheral surface 31a of the casing (the inner peripheral surface of the spiral peripheral portion of the casing 31) is reliably prevented, so that the rotation speed of the impeller 29 can be increased. The clearance between the end edge 41a and the casing inner peripheral surface 31a opposed thereto, and the clearance between the outer edge 42a of the auxiliary blade 42 and the opposed casing inner peripheral surface 31a both rotate the impeller 29. During operation, the blades are displaced as shown by a chain line in FIG.

In addition, the impeller side plate 40 is supported in a cantilevered state with respect to the impeller side plate 40, and the protrusion dimension in the rotation axis center direction from the impeller side plate 40 is smaller than the auxiliary blade 42, so that A blade extension rib 45 extending from the inner edge of the auxiliary blade 42 and extending to the edge of the central hole 40a in the donut-shaped impeller side plate 40
, Whereby the bending of the auxiliary blades 42 and the bending of the impeller side plate 40 are suppressed as much as possible.

[Second Embodiment] In the first embodiment, the outer edge 41 of each of the main blade 41 and the auxiliary blade 42 is provided.
Although an example is shown in which the a and 42a are formed in an inclined position closer to the rotation axis P toward the free end of the blade, the main blade 41, which is unlikely to be displaced by bending as shown in FIG. The outer edge 41a in the rotation radius direction is formed in a posture parallel to the rotation axis P, and the outer edge 42a in the rotation radius direction of the auxiliary blade 42, which is likely to be displaced by bending, is set closer to the free end of the blade. It may be formed in an inclined posture closer to the rotation axis P.

[Third Embodiment] In the first and second embodiments, the outer edges 41a, 42a of the blades 41, 42 are provided.
The inner peripheral surface 31a of the casing opposing to the axis is parallel to the rotation axis P, whereas the outer edges 41a, 42a of the auxiliary blades 41 and the main blades 42 are closer to the rotation axis P toward the free ends of the blades. Although the example in which the inclination posture is set is shown, instead of this, FIG.
As shown in FIG.
The inner peripheral surface 31a of the casing facing the outer edges 41a, 42a is formed so as to be inclined away from the rotation axis P toward the free end of the blade, thereby causing displacement of the free end of the blade due to bending. Each blade 41, 42 and casing inner peripheral surface 3
In order to reliably prevent contact interference with the blade 1a and increase the rotational speed of use of the impeller 29, between the outer edges 41a and 42a of the blades 41 and 42 and the casing inner peripheral surface 31a opposed thereto. During the rotation operation of the impeller 29, the clearance is set as appropriate as possible by the displacement of the blade as shown by the one-dot chain line in FIG.

[Fourth Embodiment] In the first to third embodiments, the outer edges 41a and 42a of the blades 41 and 42 are
An example is shown in which only one of the casing inner peripheral surface 31a opposed thereto is formed in an inclined posture. Instead, as shown in FIG. 11, the outer edge 41a of each of the blades 41, 42 in the rotational radius direction is provided. , 42a are inclined closer to the rotation axis P toward the blade free end, and the casing inner peripheral surface 31a facing the outer edge 41a, 42a of each of the blades 41, 42 is rotated closer to the blade free end. It is formed in an inclined posture away from the core P.

Alternatively, as shown in FIG. 12, the outer edge 41a of the main blade 41, which is unlikely to be displaced by bending, is formed in a posture parallel to the rotation axis P. On the other hand, each blade 41,
The inner peripheral surface 31a of the casing facing the outer edges 41a, 42a is inclined away from the rotation axis P toward the free end of the blade, and the outer edge 42a of the auxiliary blade 42, which is liable to be displaced by bending, is changed to the blade. The free end side has an inclined posture closer to the rotation axis P, thereby reliably preventing contact interference between the blades 41 and 42 and the inner peripheral surface 31a of the casing caused by displacement of the free end portion of the blade due to bending. In order to increase the use rotation speed of the impeller 29, the blades 41,
When the impeller 29 rotates, the clearance between the outer edges 41a, 42a and the casing inner peripheral surface 31a opposed to the outer edges 41a, 42a is as appropriate as possible due to the displacement of the blade as shown by the one-dot chain line in FIGS. So that

[Fifth Embodiment] In the first embodiment described above, a blade extension rib 45 extending from the inner edge of the auxiliary blade 42 toward the rotation axis P is provided on the impeller side plate 40, and the auxiliary blade 42 13 and the deflection of the impeller side plate 40 are suppressed, but instead of the addition of the blade extension ribs 45, or together with the addition of the blade extension ribs 45, FIG.
As shown in FIG. 14, a structure in which the plate thickness of the impeller side plate 40 is increased toward the rotation axis P, and as shown in FIG.
A structure is provided in which a plurality of convex ribs 46 extending radially in the rotational radius direction are provided in a radial manner as viewed in the direction of the rotational axis, thereby suppressing the bending of the impeller side plate 40, and causing the blades 41, 42 and the inner peripheral surface 31a of the casing are prevented from contacting with each other, and the outer edge 41 of each of the blades 41, 42 is prevented.
The clearance between the a, 42a and the casing inner peripheral surface 31a opposed thereto is stably maintained in an appropriate state.

[Sixth Embodiment] In the example shown in the first embodiment, the boss 4 of the impeller 29 with respect to the rotating shaft 43 is used.
4, an inner cylindrical portion 44a externally fitted to the rotating shaft 43, an outer cylindrical portion 44b as a connection base for the blades 41, 42 and the impeller side plate 40, and an inner cylindrical portion 44a and an outer cylindrical portion 44b.
And an annular bottom plate portion 44c extending over one end portion in the direction of the axis of rotation, the other end portion of the inner cylinder portion 44a and the outer cylinder portion 44b (that is, between the two cylinder portions 44a and 44b). The annular bottom plate portion 44c is connected to the impeller side plate 40 in the rotation axis direction with the blades 41 and 42 connected to the impeller side plate 40 in a state where the boss end on the side where the cavity is opened) is positioned corresponding to the impeller side plate 40 in the rotation axis direction. Although the structure which arrange | positions in the position spaced apart from the impeller side plate 40 on the same side as the installation side was shown, instead of this,
As shown in FIG. 15, the annular bottom plate portion 44c is
In the state where it is arranged on the same plane or almost on the same plane, the inner cylinder part 44a and the outer cylinder part 44b are
The structure is such that it is located on the same side as the side where the blades 41 and 42 are connected to the impeller side plate 40.

That is, in this boss structure, the impeller side plate 4
An annular bottom plate portion 4 located on the same plane as, or substantially on the same plane as,
Due to the presence of 4c, the rigidity of the connecting base side against bending of the impeller side plate 40 (bending to the rear side of the impeller side plate 40 due to the blades 41 and 42 in the cantilever support state) is increased, and the impeller side plate 40 is The bending is suppressed, thereby preventing the interference between the blades 41, 42 and the inner peripheral surface 31a of the casing caused by the bending, and the outer edges 41a, 42a of the blades 41, 42 and the casing facing thereto. Inner circumference 3
1a so as to stably maintain a proper clearance.

[Other Embodiments] Next, other embodiments will be listed. The outer edge 42a of the auxiliary blade 42 and the outer edge 41a of the main blade 41
These outer edges 4 are used to form a leaning posture that is closer.
Instead of forming the inclined surfaces 2a and 41a in a uniform inclination angle from the blade base end to the blade tip, as shown in FIG. 16, they are formed in an inclination posture in which the inclination angle increases toward the free end of the blade. When the free ends of the blades are displaced due to bending at the time, the outer edges 42a, 42a,
The clearance between 41a and the casing inner peripheral surface 31a opposed thereto may be made more appropriate.

In each of the embodiments described above, the example in which the auxiliary blades 42 are provided has been described. However, the invention according to claim 1 or claims 5 to 8 relates to a centrifugal blower as shown in FIG. Can also be applied.

The present invention is not limited to a centrifugal blower for a fertilizer, but can be applied to a centrifugal blower for various uses as long as the blade is provided in a cantilevered state with respect to an impeller side plate. The impeller is not limited to a resin integrally molded product, and can be applied to centrifugal blowers having various materials and assembled structures.

[Brief description of the drawings]

FIG. 1 is an overall side view of a rice transplanter with a fertilizer application device.

FIG. 2 is a rear view showing the configuration of the fertilizer application and the arrangement of the blowers.

FIG. 3 is a longitudinal sectional side view of a main part showing a configuration of a fertilizer application device.

FIG. 4 is an overall side view of a centrifugal blower.

FIG. 5 is an overall rear view of the centrifugal blower.

FIG. 6 is a cross-sectional view of a centrifugal blower.

FIG. 7 is a longitudinal sectional view of a centrifugal blower.

8A is a longitudinal sectional view of an impeller in a main blade portion. FIG. 8B is a longitudinal sectional view of an impeller in an auxiliary blade portion.

9A is a longitudinal sectional view of an impeller in a main blade portion, and FIG. 9B is a longitudinal sectional view of an impeller in an auxiliary blade portion.

FIG. 10 is a longitudinal sectional view of an impeller.

11A is a longitudinal sectional view of an impeller in a main blade portion. FIG. 11B is a longitudinal sectional view of an impeller in an auxiliary blade portion.

12A is a longitudinal sectional view of an impeller in a main blade portion. FIG. 12B is a longitudinal sectional view of an impeller in an auxiliary blade portion.

FIG. 13 is a longitudinal sectional view of an impeller.

14A is a rear view of the impeller. FIG. 14B is a longitudinal sectional view of the impeller.

FIG. 15 is a longitudinal sectional view of an impeller.

16A is a longitudinal sectional view of an impeller in a main blade part, and FIG. 16B is a longitudinal sectional view of an impeller in an auxiliary blade part.

FIG. 17 (a) Front view of impeller (b) Longitudinal sectional view of impeller

FIG. 18 is a longitudinal sectional view showing a conventional structure.

[Explanation of symbols]

29 Impeller 31 Casing 31a Casing inner peripheral surface 40 Impeller side plate 41 Main blade 41a Outer edge of main blade 42 Auxiliary blade 42a Outer edge of auxiliary blade 43 Rotating shaft 44 Boss 44a Inner cylinder 44b Outer cylinder 44c Annular Bottom plate part 45 Blade extension rib 46 Convex rib P Rotation axis θ1 Angle of inclination of outer edge of main blade θ2 Angle of inclination of outer edge of auxiliary blade

Claims (8)

[Claims] 1. A centrifugal blower in which a number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate to form an impeller, wherein an outer edge of the blade in a radial direction of rotation is formed. A centrifugal blower is formed in an inclined posture in which the blade free end side opposite to the support side with respect to the impeller side plate is closer to the rotation axis. 2. A large number of main blades extending from a position near a rotation axis to an outer peripheral portion of an impeller side plate are arranged side by side in a rotational circumferential direction in a cantilevered state with respect to the impeller side plate, and are provided on an outer peripheral portion of the impeller side plate. A centrifugal blower in which an auxiliary impeller is provided between the main impellers in a cantilevered state with respect to the impeller side plate to form an impeller, wherein an outer edge of the auxiliary impeller in a radial direction of rotation is provided. A centrifugal blower, which is formed in such a manner as to be closer to the axis of rotation as the free end of the blade is opposite to the support side of the impeller side plate. 3. The centrifugal blower according to claim 2, wherein the outer edge of each of the auxiliary blade and the main blade in the rotational radius direction is a blade free end side opposite to a support side with respect to the impeller side plate. And the inclination angle of the outer edge in the radial direction of rotation of the auxiliary blade is larger than the inclination angle of the outer edge in the radial direction of rotation of the main blade. Centrifugal blower. 4. A large number of main blades extending from near the rotation axis to the outer peripheral portion of the impeller side plate are arranged side by side in the rotational circumferential direction in a cantilevered state with respect to the impeller side plate, and are provided on the outer peripheral portion of the impeller side plate. A centrifugal blower provided with only the auxiliary blades positioned only between the main blades in a cantilevered support state with respect to the impeller side plate to form an impeller, in a cantilevered support state with respect to the impeller side plate, And, in a state where the protrusion dimension in the rotation axis direction from the impeller side plate is smaller than the auxiliary blade, a blade extension rib extending from the inner edge of the auxiliary blade in the rotation radial direction and extending toward the rotation axis side. Centrifugal blower provided. 5. A centrifugal blower in which a number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate to form an impeller, wherein a rotating part of a casing inside the impeller is provided. An inner peripheral surface of the casing that faces the outer edge of the blade in the radial direction is formed so as to be inclined away from the axis of rotation as the free end of the blade is opposite to the support side of the blade with respect to the impeller side plate. Centrifugal blower. 6. A centrifugal blower in which a number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate to form an impeller, wherein the plate thickness of the impeller side plate is determined by a rotation axis. Centrifugal blower enlarged toward the side. 7. A centrifugal blower in which a number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate to form an impeller. A centrifugal blower provided with a plurality of radially extending ribs extending in a rotation radial direction over an outer peripheral portion of the impeller side plate. 8. A centrifugal blower in which a number of blades are arranged side by side in a rotating circumferential direction in a cantilevered state with respect to an impeller side plate to form an impeller, wherein a boss portion of the impeller with respect to a rotating shaft is provided. An inner cylinder portion that fits over the rotation shaft, an outer cylinder portion as a connection base for the blades and the impeller side plate, and one end of the inner cylinder portion and the outer cylinder portion in the rotation axis center direction. The inner cylindrical portion and the outer cylindrical portion are formed on the annular bottom plate portion in a state where the annular bottom plate portion is formed on the same surface or substantially the same surface as the impeller side plate. On the other hand, a centrifugal blower located on the same side as the side where the blades are connected to the impeller side plate.