Belt guard and belt-driven blower

Abstract

To provide a belt guard which can secure the strength in torsion directions of the belt guard and can reduce the weight thereof at higher levels.SOLUTION: A belt guard includes a main body plate part GM constituted so as to be arranged on the side opposite to a blower main body part of a belt driving type blower with respect to a belt driving part of the belt driving type blower. The main body plate part has an offset design K represented by the unevenness in a belt guard depth direction. The offset design has a back ground part KB and a plurality of shape parts KN located on either one side in the belt guard depth direction. The back ground part is extended, with an annular first outer circumferential part KR1, in directions inclined with respect to both in a belt guard short side direction and a belt guard long side direction, and at the same time both end parts communicate with the first outer circumferential part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a belt guard and a belt-driven blower. [Background technology]

[0002] Conventionally, a belt-driven fan is provided with a belt guard that covers a belt drive portion (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6576647 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional belt guards, there has been a demand to achieve a higher level of both strength in the torsional direction and weight reduction, which are in a contradictory relationship with each other.

[0005] An object of the present invention is to provide a belt guard and a belt-driven blower that are capable of achieving both sufficient torsional strength in the belt guard and lightweight construction at a higher level. [Means for solving the problem]

[0006] [1] A belt guard for a belt-driven blower, a main body plate portion configured to be disposed on an opposite side of the belt drive portion of the belt drive type blower from the blower main body portion of the belt drive type blower, The main body plate portion has an offset pattern that is expressed by unevenness in the belt guard depth direction, The offset pattern is A background part; A plurality of shaped portions located on either side of the background portion in the belt guard depth direction; It has The background portion is An annular first outer periphery; A pair of inclined dividing line portions each extending in a direction inclined with respect to both the belt guard short-side direction and the belt guard long-side direction, both ends of which are connected to the first outer circumferential portion, and which intersect with each other on the center of the main body plate portion; A lateral dividing line portion extending in a lateral direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at a center of the main body plate portion; It has The first outer peripheral portion includes a pair of short-side outer peripheral portions that connect the ends of the pair of inclined dividing line portions on both sides of the belt guard in the longitudinal direction and extend in a substantially short-side direction of the belt guard, The pair of outer peripheral portions in the short side direction have inner end edges in the longitudinal direction of the belt guard that extend linearly in the short side direction of the belt guard over the entire length of the inner end edges in the longitudinal direction of the belt guard, The belt guard, wherein the plurality of shaped portions are defined between the first outer peripheral portion, the pair of inclined direction dividing line portions, and the short side direction dividing line portions.

[0007] [2] The belt guard described in [1], wherein each of the multiple shaped portions is approximately triangular in shape.

[0008] [3] The background portion is A longitudinal dividing line portion extending in the longitudinal direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at the center of the main body plate portion. and The belt guard described in [1] or [2], wherein the multiple shaped portions are defined between the first outer peripheral portion, the pair of inclined dividing line portions, the short-side dividing line portions, and the long-side dividing line portions.

[0009] [4] A side plate portion extending from an outer peripheral edge of the main body plate portion toward a first side in the belt guard depth direction; A back plate portion extending from an end edge of the side plate portion on a first side in the belt guard depth direction toward an inner peripheral side; A folded plate portion is folded back from an inner peripheral edge of the back plate portion toward a second side in the belt guard depth direction and extends toward an outer peripheral side; The belt guard according to any one of [1] to [3], further comprising:

[0010] [5] The belt guard according to any one of [1] to [4], wherein the belt guard has a substantially octagonal shape in a plan view.

[0011] [6] The belt guard according to any one of [1] to [5], wherein the main body plate portion has a plate thickness of 0.8 to 1.6 mm.

[0012] [7] The belt guard according to any one of [1] to [6], wherein the belt guard is formed by connecting a plurality of members formed separately from each other by riveting.

[0013] [8] A belt guard according to any one of [1] to [7], The belt drive unit; The blower main body, A belt-driven blower. Effect of the Invention

[0014] According to the present invention, it is possible to provide a belt guard and a belt-driven fan that can achieve both ensuring the strength of the belt guard in the torsional direction and reducing its weight at a higher level. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a belt-driven blower according to an embodiment of the present invention; [Diagram 2] 2 is a view taken in the direction of arrow A in FIG. 1 showing the belt-driven blower of FIG. 1. [Diagram 3] 2 is a view taken in the direction of the arrow B in FIG. 1 showing the belt-driven blower of FIG. 1; [Figure 4] 1 is a plan view showing a belt guard according to an embodiment of the present invention, viewed from a second side in the belt guard depth direction toward a first side in the belt guard depth direction. FIG. [Diagram 5] 5 is a perspective view showing the belt guard of FIG. 4 as viewed obliquely from a second side in the belt guard depth direction. FIG. [Figure 6] FIG. 6 is an exploded perspective view showing the belt guard of FIG. 5 in an exploded state. [Figure 7] 7(a) is a perspective view of the belt guard of FIG. 5 taken along the line CC in FIG. 5, and FIG. 7(b) is an enlarged view of part D of FIG. 7(a). [Figure 8] FIG. 8 is an enlarged view of part E in FIG. 7(a). [Figure 9] 5 is a perspective view showing the belt guard of FIG. 4 as viewed obliquely from a first side in the belt guard depth direction. FIG. [Figure 10] FIG. 5 is a plan view corresponding to FIG. 4 and showing a schematic view of the belt guard according to the first modified example of the present invention, as viewed from the second depth side of the belt guard toward the first depth side of the belt guard. [Figure 11] FIG. 5 is a plan view corresponding to FIG. 4 and showing a belt guard according to a second modified example of the present invention, viewed from a second depth side of the belt guard toward a first depth side of the belt guard. [Figure 12] FIG. 5 is a plan view corresponding to FIG. 4 and showing a belt guard according to a third modified example of the present invention, viewed from a second depth side of the belt guard toward a first depth side of the belt guard. [Figure 13] FIG. 5 is a plan view corresponding to FIG. 4 and showing a schematic view of a belt guard according to a fourth modified example of the present invention, as viewed from a second depth side of the belt guard toward a first depth side of the belt guard. [Figure 14]Figures 14(a) and 14(b) are plan views that roughly show the appearance of models of belt guards of different examples used in the analysis, as viewed from the second depth side of the belt guard toward the first depth side of the belt guard. [Figure 15] 15(a) to 15(d) are plan views each showing a schematic view of a model of a belt guard of a different example used in the analysis, as viewed from a second depth side of the belt guard toward a first depth side of the belt guard. [Figure 16] Figures 16(a) and 16(b) are side views each showing a schematic view of a model of a belt guard of a different example used in the analysis, viewed from the second side in the short side direction of the belt guard towards the first side in the short side direction of the belt guard. [Figure 17] FIG. 11 is an explanatory diagram for explaining the twist direction of the belt guard. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The belt guard and belt-driven blower of the present invention can be suitably applied to any type of belt-driven blower, and can be particularly suitably applied to belt-driven blowers equipped with a belt guard whose total longitudinal length is approximately 2 m or more.

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a belt guard and a belt-driven blower according to the present invention will be described with reference to the drawings.

[0018] Fig. 1 to Fig. 3 show a belt-driven blower 1 according to one embodiment of the present invention. Fig. 1 is a perspective view showing, in outline, the belt-driven blower 1 according to one embodiment of the present invention. Fig. 2 is a view seen from the direction of the arrow A in Fig. 1, showing the belt-driven blower 1 in Fig. 1. Fig. 3 is a view seen from the direction of the arrow B in Fig. 1, showing the belt-driven blower 1 in Fig. 1. Figs. 4 to 9 show a belt guard G according to one embodiment of the present invention.

[0019] First, the basic configuration of a belt-driven blower 1 of the present embodiment will be described mainly with reference to Figs. 1 to 3. As shown in FIGS. 1 to 3, a belt-driven blower 1 of this embodiment includes a belt guard G according to one embodiment of the present invention, a belt drive section D, and a blower main body section F.

[0020] The belt guard G has a length in one direction longer than the length in a direction perpendicular thereto in a plan view (FIG. 4). In this specification, for convenience of explanation, as shown with arrows in each drawing, the extension direction of the belt guard G when viewed in a plane (FIG. 4), i.e., the longitudinal direction of the belt guard G, is referred to as the "belt guard longitudinal direction (LD)", one side and the other side in the belt guard longitudinal direction (LD) are referred to as the "belt guard longitudinal direction first side (LD1)" and the "belt guard longitudinal direction second side (LD2)", respectively. The short side direction is called "belt guard short side direction (SD)", one side and the other side in the belt guard short side direction (SD) are called "belt guard short side first side (SD1)" and "belt guard short side second side (SD2)", respectively, and the depth direction of the belt guard G is called "belt guard depth direction (DD)", one side and the other side in the belt guard depth direction (DD) are called "belt guard depth direction first side (DD1)" and "belt guard depth direction second side (DD2)", respectively. The belt guard long side direction (LD), belt guard short side direction (SD), and belt guard depth direction (DD) are perpendicular to each other. The length of the belt guard long side direction LD of the belt guard G is longer than the length of the belt guard short side direction SD. In this specification, a plan view of the belt guard G refers to a view of the belt guard G in the belt guard depth direction DD from the belt guard depth direction second side DD2 toward the belt guard depth direction first side DD1, as illustrated in FIG.

[0021] The blower main body F includes a base F1, a casing F2, an impeller F3, an impeller shaft F4, a motor F5, and a motor shaft F6. The base F1 is configured to be placed on a floor surface, the ground, or the like. The casing F2 and the motor F5 are each mounted on a base F1. The impeller F3 is housed in the casing F2. The impeller shaft F4 is the main shaft of the impeller F3 and is fixed to the impeller F3. The impeller shaft F4 extends in the belt guard depth direction DD and protrudes from the casing F2 to the belt guard depth direction second side DD2. The motor shaft F6 is an output shaft of the motor F5. The motor shaft F6 extends in the belt guard depth direction DD.

[0022] In the example of Figs. 1 to 3, the motor F5 is disposed on the left side of the casing F2 when viewed toward the belt guard depth direction first side DD1. In this case, when viewed toward the belt guard depth direction first side DD1, the belt guard extension direction first side LD1 can be directed toward the right and upward as in the example of Figs. 1 to 3. However, when viewed toward the belt guard depth direction first side DD1, the motor F5 may be disposed on the right side of the casing F2. In this case, when viewed toward the belt guard depth direction first side DD1, the belt guard extension direction first side LD1 can be directed toward the right and downward. However, the belt guard extension direction first side LD1 when viewed toward the belt guard depth direction first side DD1 may be directed in any direction. The motor F5 may be configured to rotate the motor shaft F6 to the right or to the left when viewed toward the first side DD1 in the belt guard depth direction. Furthermore, the casing F2 may be oriented so that its discharge port faces in any direction, not limited to the direction shown in FIG.

[0023] The belt drive unit D includes an impeller-side pulley D1, a motor-side pulley D2, and a belt D3. The impeller-side pulley D1 is fixed to an end of the impeller shaft F4 on a second side DD2 in the belt guard depth direction. The motor-side pulley D2 is fixed to an end of the motor shaft F6 on the second side DD2 in the belt guard depth direction. The belt D3 is, for example, a V-belt. The belt D3 is circular and is wound around the impeller pulley D1 and the motor pulley D2.

[0024] In the belt-driven blower 1 configured as described above, while the motor F5 is driven, the motor-side pulley D2 rotates in conjunction with the motor shaft F6, and the torque is transmitted to the impeller-side pulley D1 via the belt D3. The impeller shaft F4 and thus the impeller F3 rotate in conjunction with the impeller-side pulley D1. The rotation of the impeller F3 exerts a blowing function.

[0025] The belt guard G is configured to cover the belt drive unit D, specifically, to cover at least the side of the belt drive unit D opposite to the blower main body unit F (i.e., at least the second side DD2 in the belt guard depth direction relative to the belt drive unit D). This makes it possible to prevent people and the like from interfering with the belt drive unit D. In this embodiment, the belt guard G is configured to cover at least the side of the belt drive unit D opposite the blower main body unit F relative to the belt drive unit D (i.e., at least the belt guard depth direction second side DD2 relative to the belt drive unit D) and the outer circumferential side of the belt drive unit D.

[0026] In this embodiment, the belt guard G is fixed to the blower body F. More specifically, in this embodiment, both ends of the belt guard G in the belt guard longitudinal direction LD are fixed to the blower body F via connecting members J1 and J2 made of steel plates or the like. More specifically, in this embodiment, a side plate portion GSc (FIG. 5) on a belt guard longitudinal direction first side LD1 of the belt guard G described later is fixed to a casing F2 of the blower body F via a connecting member J1 (FIGS. 1 and 2), and a side plate portion GSd (FIGS. 5 and 6) on a belt guard longitudinal direction second side LD2 of the belt guard G described later is fixed to a base F1 of the blower body F via a connecting member J2 (FIG. 1). However, the belt guard G may be fixed to the blower body F in a form different from this embodiment. The belt guard G and the connecting members J1 and J2 are connected to each other by, for example, fastening.

[0027] The belt guard G of this embodiment will be described in more detail below, mainly with reference to Figs. 4 to 9. Fig. 4 is a plan view showing the belt guard G according to one embodiment of the present invention, viewed from the belt guard depth direction second side DD2 toward the belt guard depth direction first side DD1. Fig. 5 is a perspective view showing the belt guard G of Fig. 4 viewed obliquely from the belt guard depth direction second side DD2. Fig. 6 is an exploded perspective view showing the belt guard G of Fig. 5 disassembled. Fig. 7(a) is a CC cross-sectional perspective view showing the belt guard G of Fig. 5 together with a cross section along the line CC of Fig. 5, and Fig. 7(b) is an enlarged view of part D of Fig. 7(a). Fig. 8 is an enlarged view of part E of Fig. 7(a). Fig. 9 is a perspective view showing the belt guard G of Fig. 4 viewed obliquely from the belt guard depth direction first side DD1. As shown in Fig. 4 to Fig. 9, the belt guard G of this embodiment is configured in a substantially box shape. The belt guard G is mainly configured from one or more plate members. The one or more plate members constituting the belt guard G are preferably, for example, steel plates. The belt guard G of this embodiment includes a main plate portion GM, a side plate portion GS, a back plate portion GB, and a folded-back plate portion GR.

[0028] The main body plate part GM is configured to be disposed on the opposite side of the belt drive part D from the blower main body part F (i.e., the second side DD2 in the belt guard depth direction from the belt drive part D) (FIG. 1). As a result, the main body plate part GM is configured to cover the side of the belt drive part D opposite to the blower main body part F (i.e., the second side DD2 in the belt guard depth direction from the belt drive part D). The main body plate portion GM is perpendicular to the belt guard depth direction DD, that is, the belt guard depth direction DD corresponds to the plate thickness direction of the main body plate portion GM. The portion of the belt guard on the first longitudinal side LD1 of the main body plate portion GM is configured to face either one of the impeller side pulley D1 and the motor side pulley D2 (in the example of Figures 1 to 3, the impeller side pulley D1) in the belt guard depth direction DD, and the portion of the belt guard on the second longitudinal side LD2 of the main body plate portion GM is configured to face the other of the impeller side pulley D1 and the motor side pulley D2 (in the example of Figures 1 to 3, the motor side pulley D2) in the belt guard depth direction DD.

[0029] In this specification, the center of the main body plate portion GM when viewed in a plane (i.e., the center of the main body plate portion GM in the belt guard longitudinal direction LD and the belt guard lateral direction SD) is referred to as the "main body plate portion center (GMC)" (Figure 4). Furthermore, when describing the belt guard G in this specification, unless otherwise specified, the terms "circumferential direction," "outer peripheral side," "inner peripheral side," etc. refer to the circumferential direction, outer peripheral side, inner peripheral side, etc., respectively, when centered on an axis that passes through the center GMC of the main body plate portion and extends in the depth direction DD of the belt guard. Furthermore, in this specification, the side closer to the center GMC of the main body plate portion in the belt guard longitudinal direction LD is referred to as the "belt guard longitudinal direction (LD) inner side", the side farther from the center GMC of the main body plate portion in the belt guard longitudinal direction LD is referred to as the "belt guard longitudinal direction (LD) outer side", the side closer to the center GMC of the main body plate portion in the belt guard transverse direction SD is referred to as the "belt guard transverse direction (SD) inner side", and the side farther from the center GMC of the main body plate portion in the belt guard transverse direction SD is referred to as the "belt guard transverse direction (SD) outer side".

[0030] In this embodiment, the belt guard G (and thus the main body plate portion GM) is substantially octagonal in plan view. Accordingly, the outer peripheral edge of the main body plate portion GM, as shown in Fig. 4 and Fig. 5, is composed of a pair of outer peripheral edge portions GMa, GMb extending parallel to each other in the belt guard longitudinal direction LD, a pair of outer peripheral edge portions GMc, GMd extending parallel to each other in the belt guard lateral direction SD, and four outer peripheral edge portions GMe, GMf, GMg, GMh connecting the pair of outer peripheral edge portions GMa, GMb and the pair of outer peripheral edge portions GMc, GMd and extending linearly in a direction inclined with respect to both the belt guard longitudinal direction LD and the belt guard lateral direction SD. Because the belt guard G has a substantially octagonal shape in plan view, compared to a case in which the belt guard G has a substantially rectangular shape in plan view, the four corners are rounded off, and even if the position of the belt guard G is lowered, the corners of the belt guard G are less likely to hit the floor or ground when the belt guard G is placed tilted from the horizontal as in the example of Figures 1 to 3, making it possible to make the belt-driven blower 1 more compact. In addition, because the belt guard G has a substantially octagonal shape in plan view, processing is easier compared to a case in which the belt guard G has a shape including curved portions, such as a substantially elliptical shape, in plan view. Furthermore, since the belt guard G has an approximately octagonal shape in a plan view, when viewed toward the belt guard depth direction first side DD1, it is possible to use belt guard G of the same shape both when the belt guard extension direction first side LD1 is oriented toward the right and upward (Figure 1) and when it is oriented toward the right and downward (not shown); in other words, there is no need to prepare belt guards G of different shapes depending on the orientation direction of the belt guard G. However, the belt guard G (and thus the main body plate portion GM) may have any shape in plan view, such as a substantially rectangular shape, a substantially elliptical shape, etc. It is preferable that the outer peripheral edge of the main body plate portion GM has at least a pair of outer peripheral edge portions GMa, GMb extending parallel to each other in the belt guard longitudinal direction LD, and more preferably further has a pair of outer peripheral edge portions GMc, GMd extending parallel to each other in the belt guard lateral direction SD.

[0031] The main body plate portion GM and therefore the belt guard G may have a total length in the belt guard longitudinal direction LD (the distance between a pair of outer peripheral edge portions GMc, GMd in the example of FIG. 4) of, for example, 1.0 m or more. Also, the belt guard G may have a total length in the belt guard longitudinal direction LD of, for example, 3.0 m or less. The main body plate portion GM and therefore the belt guard G may have a total length in the belt guard short-side direction SD (the distance between a pair of outer peripheral edge portions GMa, GMb in the example of FIG. 4) of, for example, 30 cm or more. short hand DirectionS The total length of D may be, for example, 80 cm or less.

[0032] The main body plate portion GM has an offset pattern K that appears as unevenness in the belt guard depth direction DD (Fig. 4). As can be seen from Figs. 7 and 8, the main body plate portion GM has a substantially uniform plate thickness T (Fig. 8) over its entirety. The unevenness in the belt guard depth direction DD that constitutes the offset pattern K can be formed by performing offset processing on the flat plate member that constitutes the main body plate portion GM during the manufacture of the belt guard G. By having the main body plate portion GM have the offset pattern K, the rigidity of the main body plate portion GM and therefore the belt guard G (particularly the rigidity in the torsional direction) can be improved compared to a case in which the main body plate portion GM is flat and plate-like.

[0033] As shown in Fig. 4, the offset pattern K has a background portion KB and multiple shape portions KN. As shown in Fig. 7 and Fig. 8, the multiple shape portions KN are located (i.e., offset) from the background portion KB on one side of the belt guard depth direction DD (in the example shown, the belt guard depth direction first side DD1). It is preferable that the background portion KB is continuous and substantially flat throughout its entirety, and it is also preferable that the offset amount OS (FIG. 8) of each of the plurality of shape portions KN with respect to the background portion KB is substantially uniform throughout the shape portion KN and is substantially the same among the shape portions KN. The offset amount OS (Figure 8) between the background portion KB and the shape portion KN is the distance in the belt guard depth direction DD between the surface of the belt guard on the second depth side DD2 in the background portion KB and the surface of the belt guard on the second depth side DD2 in the shape portion KN.

[0034] As shown in Fig. 4, the background portion KB has a substantially truss shape. In this embodiment, the background portion KB has a first outer peripheral portion KR1, a pair of inclined direction dividing line portions KI, and a short side direction dividing line portion KS (more specifically, in the example of Fig. 4, the background portion KB has only these).

[0035] The first outer circumferential portion KR1 extends entirely around the main body plate portion center GMC, that is, has an annular shape. As shown in Fig. 4, the outer peripheral edge of the first outer peripheral portion KR1 is preferably annular and has substantially the same shape as the outer peripheral edge of the main body plate portion GM (substantially octagonal in the example of Fig. 4) so ​​as to fit along the outer peripheral edge of the main body plate portion GM. In the example of Fig. 4, the outer peripheral edge of the first outer peripheral portion KR1 is located on the inner peripheral side of the outer peripheral edge of the main body plate portion GM, and the distance from the outer peripheral edge of the main body plate portion GM is substantially constant over the entire circumference.

[0036] The pair of oblique direction dividing line portions KI extend in a direction inclined with respect to both the belt guard short-side direction SD and the belt guard long-side direction LD. The extending direction of the oblique direction dividing line portion KI is the extending direction of the center line KIc (a line consisting of a collection of center points in the width direction of the oblique direction dividing line portion KI) of the oblique direction dividing line portion KI. Both ends of the pair of oblique direction dividing line portions KI are connected to the first outer peripheral portion KR1. The pair of oblique direction dividing line portions KI intersect with each other on the main body plate portion center GMC. The first oblique direction dividing line portion KI1, which is one of the pair of oblique direction dividing line portions KI, extends to the belt guard short-side direction first side SD1 as it approaches the belt guard long-side direction first side LD1, and the second oblique direction dividing line portion KI2, which is the other of the pair of oblique direction dividing line portions KI, extends to the belt guard short-side direction second side SD2 as it approaches the belt guard long-side direction first side LD1. The pair of oblique direction dividing line portions KI are generally X-shaped. As shown in the example of Fig. 4, it is preferable that the center lines KIc of the pair of oblique direction dividing line portions KI extend in a straight line. It is preferable that the center lines KIc of the pair of oblique direction dividing line portions KI intersect with each other on the main body plate portion center GMC. It is preferable that the acute angle of the center lines KIc of the pair of oblique direction dividing line portions KI with respect to the belt guard longitudinal direction LD is the same as each other. The acute angle of each center line KIc of the pair of inclined dividing line portions KI with respect to the belt guard longitudinal direction LD is, for example, 5° to 40°.

[0037] The short-side dividing line portion KS extends in the short-side direction SD of the belt guard. The extending direction of the short-side dividing line portion KS is the extending direction of the center line KSc of the short-side dividing line portion KS (a line consisting of a collection of center points in the width direction of the short-side dividing line portion KS). Both ends of the short-side dividing line portion KS are connected to the first outer periphery portion KR1. The short-side dividing line portion KS intersects with a pair of inclined dividing line portions KI on the main body plate portion center GMC. As shown in the example of Fig. 4, it is preferable that the center line KSc of the short-side dividing line portion KS extends in a straight line. It is preferable that the center line KSc of the short-side dividing line portion KS intersects with a pair of inclined dividing line portions KI on the main body plate portion center GMC.

[0038] As shown in FIG. 4, the first outer circumferential portion KR1 includes a pair of lateral outer circumferential portions KR1S and a pair of longitudinal outer circumferential portions KR1L. A pair of short-side outer peripheral portions KR1S extend substantially in the short-side direction SD of the belt guard on both sides of the belt guard longitudinal direction LD relative to the body plate center GMC. The extension direction of the short-side outer peripheral portion KR1S is the extension direction of the center line of the short-side outer peripheral portion KR1S (a line consisting of a collection of center points in the width direction of the short-side outer peripheral portion KR1S). The pair of short-side outer peripheral portions KR1S connect the ends of the pair of inclined direction dividing line portions KI on the corresponding sides in the belt guard longitudinal direction LD on both sides of the belt guard longitudinal direction LD relative to the body plate center GMC. That is, the short-side outer peripheral portion KR1S located on the belt guard longitudinal direction first side LD1 relative to the body plate center GMC connects the ends of the pair of inclined direction dividing line portions KI on the belt guard longitudinal direction first side LD1. The short-side outer peripheral portion KR1S located on the belt guard second longitudinal side LD2 with respect to the main body plate portion center GMC connects the ends of the belt guard second longitudinal sides LD2 of the pair of inclined dividing line portions KI to each other. Both ends of each short-side outer peripheral portion KR1S are located on the ends of the pair of inclined dividing line portions KI on the corresponding side in the belt guard longitudinal direction LD. The pair of short-side outer peripheral portions KR1S have their inner edge KR1Sa in the belt guard longitudinal direction LD extending linearly in the belt guard short-side direction SD over the entire length of the inner edge KR1Sa in the belt guard longitudinal direction LD (and thus the entire length of the short-side outer peripheral portions KR1S). In the example of Figure 4, the outer edge KR1Sb of each of the pair of short-side outer peripheral portions KR1S in the belt guard longitudinal direction LD does not extend in a straight line in the belt guard short-side direction SD over the entire length of the outer edge KR1Sb in the belt guard longitudinal direction LD (and thus the entire length of the short-side outer peripheral portion KR1S), but has a non-linear shape along the outer peripheral edge of the main body plate portion GM (specifically, the portion of the outer peripheral edge of the main body plate portion GM excluding the pair of outer peripheral edge portions GMa, GMb extending in the belt guard longitudinal direction LD (outer peripheral edge portions GMe, GMc, GMf and outer peripheral edge portions GMg, GMd, GMh)), and more specifically, forms a bent shape (bent line shape) convex outward in the belt guard longitudinal direction LD. However, the outer edge KR1Sb of each of the pair of short-side outer peripheral portions KR1S in the belt guard longitudinal direction LD may have any non-linear shape different from the example of Figure 4, or may extend linearly in the belt guard short-side direction SD over the entire length of the outer edge KR1Sb of each of the belt guard longitudinal direction LD (and thus the entire length of the short-side outer peripheral portions KR1S). A pair of longitudinal outer peripheral portions KR1L extend linearly in the belt guard longitudinal direction LD on both sides of the belt guard lateral direction SD relative to the main body plate center GMC. The longitudinal outer peripheral portion KR1L extends in the direction of the center line of the longitudinal outer peripheral portion KR1L (a line consisting of a collection of center points in the width direction of the longitudinal outer peripheral portion KR1L). A pair of longitudinal outer peripheral portions KR1L connects the ends of the pair of inclined direction dividing line portions KI on the corresponding sides in the belt guard lateral direction SD on both sides of the belt guard lateral direction SD relative to the main body plate center GMC. That is, the longitudinal outer peripheral portion KR1L located on the belt guard lateral direction first side SD1 relative to the main body plate center GMC connects the ends of the pair of inclined direction dividing line portions KI on the belt guard lateral direction first side SD1. The longitudinal outer peripheral portion KR1L located on the belt guard second short-side side SD2 with respect to the main body plate portion center GMC connects the ends of the pair of inclined dividing line portions KI on the belt guard second short-side side SD2. Both ends of each longitudinal outer peripheral portion KR1L are located on the ends of the pair of inclined dividing line portions KI on the corresponding side in the belt guard short-side direction SD.

[0039] The multiple shape portions KN are portions corresponding to multiple closed regions defined by the background portion KB having a substantially truss shape as described above. That is, the multiple shape portions KN are defined between the first outer periphery portion KR1 of the background portion KB, the pair of inclined direction dividing line portions KI, and the short side direction dividing line portions KS. The first outer periphery portion KR1 is located on the outer periphery side of the multiple shape portions KN. In this embodiment, the multiple shaped portions KN include four first shaped portions KN1 and two second shaped portions KN2. The four first shape portions KN1 are each defined between the first outer peripheral portion KR1 (specifically, the longitudinal outer peripheral portion KR1L) and one of the inclined direction dividing line portions KI and the transverse direction dividing line portions KS. The four first shape portions KN1 are located on both sides of the belt guard longitudinal direction LD and on both sides of the belt guard transverse direction SD with respect to the body plate portion center GMC. Each side of the shape of the first shape portion KN1 is defined by (i.e., extends along) the first outer peripheral portion KR1 (specifically, the longitudinal outer peripheral portion KR1L), the inclined direction dividing line portion KI, and the transverse direction dividing line portion KS. The shapes of the first shape portions KN1 are substantially the same as each other. The two second shape portions KN2 are located on both sides of the belt guard longitudinal direction LD with respect to the main body plate portion center GMC, and are each defined between a first outer periphery KR1 (specifically, a short-side outer periphery portion KR1S) and a pair of inclined direction dividing lines KI. Each side of the shape of the second shape portion KN2 is defined by (i.e., extends along) the first outer periphery KR1 (specifically, a short-side outer periphery portion KR1S) and a pair of inclined direction dividing lines KI. The shapes of the second shape portions KN2 are substantially the same as each other. As shown in the example of Fig. 4, it is preferable that at least a part of each side of the shape of each shaped portion KN (the whole in the example of Fig. 4) extends linearly. It is preferable that each corner (vertex) of the shape of each shaped portion KN is a curved line shape without sharp edges as shown in the example of Fig. 4, but they may be sharp edges.

[0040] As described above, in this embodiment, the main body plate portion GM has an offset pattern K, and the offset pattern K has a background portion KB and a plurality of shape portions KN, the background portion KB has a first outer peripheral portion KR1, a pair of inclined direction dividing line portions KI and a short-side direction dividing line portion KS, and the pair of short-side direction outer peripheral portions KR1S of the first outer peripheral portion KR1 extend linearly in the short-side direction SD of the belt guard over the entire length of the inner edge KR1Sa of the belt guard in the longitudinal direction LD, and the plurality of shape portions KN are defined between the first outer peripheral portion KR1, the pair of inclined direction dividing line portions KI and the short-side direction dividing line portions KS in the background portion KB. In this way, the background portion KB and the offset pattern K form a substantially truss shape. This makes it possible to achieve both ensuring the strength in the torsional direction of the belt guard G and reducing its weight at a higher level compared to when the main body plate portion GM does not have the offset pattern K and is flat, or when the offset pattern K of the main body plate portion GM is not substantially truss-shaped. Therefore, for example, it is possible to reduce the weight of the belt guard G while maintaining the same strength in the torsional direction. Alternatively, conversely, it is also possible to improve the strength in the torsional direction of the belt guard G while maintaining the same weight. Here, the twisting direction of the belt guard G refers to the direction in which the belt guard G is twisted so as to rotate in opposite directions around an axis extending substantially in the belt guard longitudinal direction LD on both sides of the belt guard longitudinal direction LD relative to the body plate portion center GMC, as shown diagrammatically in Fig. 17. Since the belt guard G is long in the belt guard longitudinal direction LD, it is required to ensure strength in such a twisting direction. In addition, as a method for ensuring the strength of the belt guard G in the torsional direction, for example, the thickness of the belt guard G may be increased or a reinforcing frame may be attached by welding to the back surface of the belt guard G (the surface of the belt guard on the first side DD1 in the depth direction). However, in such a case, the material cost and manufacturing cost are high, and the mass is large, making it difficult to attach and detach the belt guard G to the blower body F, and measures to ensure the strength to support the mass of the belt guard G (increasing the plate thickness, reinforcing, etc.) are required in the blower body F, which may lead to an increase in costs. In this regard, according to the method of the present embodiment, for example, it is possible to reduce the plate thickness of the belt guard G or to eliminate the need for a reinforcing frame while sufficiently ensuring the strength of the belt guard G in the torsional direction, which in turn makes it possible to reduce the material cost and manufacturing cost and improve the workability.

[0041] The configuration of the belt guard G is not limited to the examples shown in Fig. 4 to Fig. 9, and various modified examples are possible. Modified examples and preferable configurations of the belt guard G will be described below with reference to Fig. 10 to Fig. 13. Fig. 10 to Fig. 13 are plan views corresponding to Fig. 4, and each of them is a schematic plan view showing the belt guard G according to a different modified example of the present invention, viewed from the belt guard depth direction second side DD2 toward the belt guard depth direction first side DD1.

[0042] As in the examples of Figures 10, 12, and 13, the background portion KB may further have a longitudinal demarcation line portion KL. The longitudinal demarcation line portion KL extends in the belt guard longitudinal direction LD. The extension direction of the longitudinal demarcation line portion KL is the extension direction of the center line of the longitudinal demarcation line portion KL (a line consisting of a collection of center points in the width direction of the longitudinal demarcation line portion KL). Both ends of the longitudinal demarcation line portion KL are connected to the first outer peripheral portion KR1. The longitudinal demarcation line portion KL intersects with a pair of inclined demarcation line portions KI on the main body plate portion center GMC. It is preferable that the center line of the longitudinal demarcation line portion KL extends linearly. It is preferable that the center line of the longitudinal demarcation line portion KL intersects with a pair of inclined demarcation line portions KI on the main body plate portion center GMC. When the background portion KB further has a longitudinal dividing line portion KL, the multiple shape portions KN are defined between the first outer periphery KR1, the pair of inclined dividing line portions KI, the transverse dividing line portions KS, and the longitudinal dividing line portions KL in the background portion KB. In this case, the multiple shape portions KN can be said to be defined between the first outer periphery KR1, the pair of inclined dividing line portions KI, and the transverse dividing line portions KS in the background portion KB. In this case, the multiple shape portions KN include four third shape portions KN3 instead of the two second shape portions KN2 in the example of FIG. 4. The four third shape portions KN3 are defined between the first outer periphery KR1, any one of the inclined dividing line portions KI, and the longitudinal dividing line portion KL. The four third shape portions KN3 are located on both sides of the belt guard longitudinal direction LD and on both sides of the belt guard transverse direction SD with respect to the main body plate portion center GMC. Each side of the shape of the third shape portion KN3 is defined by (i.e., extends along) the first outer periphery KR1, the inclined dividing line portion KI, and the longitudinal dividing line portion KL. The shapes of the third shape portions KN3 are substantially the same as each other. In this way, even when the background portion KB further has a longitudinal dividing line portion KL, the background portion KB and thus the offset pattern K form an approximately truss shape, making it possible to achieve an even higher level of compatibility between ensuring the torsional strength of the belt guard G and reducing its weight.

[0043] Each of the multiple shaped portions KN may have any shape. It is preferable that each of the plurality of shaped portions KN has a substantially triangular shape, as in the examples shown in Fig. 4 and Fig. 10 to Fig. 13. This makes it possible to achieve both the strength in the torsional direction of the belt guard G and the weight reduction at a higher level. It is preferable that each of the first shape portions KN1 has a substantially right-angled triangular shape, as in the examples shown in FIG. 4 and FIG. 10 to FIG. It is preferable that each second shape portion KN2 has a substantially isosceles triangle shape as in the examples shown in Fig. 4 and Fig. 11. It is also preferable that each second shape portion KN2 has a substantially sector shape as in another modified example shown in Fig. 15(a). It is preferable that each of the third shaped portions KN3 has a substantially right-angled triangular shape, as in the examples shown in FIGS.

[0044] As shown in each example in FIG. 4 to FIG. 13, the offset pattern K may further have a second outer periphery KR2. The second outer periphery KR2 is defined between the background portion KB (and thus the first outer periphery KR1 of the background portion KB) and the outer periphery edge of the main body plate portion GM. The second outer periphery KR2 extends all around the main body plate portion center GMC, that is, it is annular. As shown in FIG. 7(a), the second outer periphery KR2 is located (i.e., offset) on the same side as the multiple shape portions KN in the belt guard depth direction DD (in the example shown in the figure, the first side DD1 in the belt guard depth direction) with respect to the background portion KB. The offset amount between the background portion KB and the second outer periphery KR2 is the same as the offset amount OS (FIG. 8) between the background portion KB and the shape portions KN. When the offset pattern K has the second outer peripheral portion KR2, the strength in the torsional direction can be improved compared to when the offset pattern K does not have the second outer peripheral portion KR2, and thus it is possible to achieve both the torsional strength of the belt guard G and lightweight construction at an even higher level. The offset amount between the background portion KB and the second outer peripheral portion KR2 is the distance in the belt guard depth direction DD between the surface of the belt guard on the second depth side DD2 at the background portion KB and the surface of the belt guard on the second depth side DD2 at the second outer peripheral portion KR2.

[0045] As in the examples shown in Figs. 4 and 10, the main body plate portion GM may not be divided and may be composed of only one plate member. Alternatively, as in the examples shown in Fig. 11 and Fig. 13, the main body plate portion GM may be divided along a short-side parting line PS extending in the short-side direction SD of the belt guard. In this case, the main body plate portion GM is a pair of separate plate members located on both sides of the short-side parting line PS, which are connected by fastening or the like on the short-side parting line PS. Specifically, for example, the main body plate portion GM may be a pair of separate plate members located on both sides of the short-side parting line PS, each of which has a bent portion extending to one side of the belt guard depth direction DD on the short-side parting line PS, and the bent portions of the plate members may be connected by fastening or the like in a state where they are overlapped on the short-side parting line PS. As in the examples shown in Fig. 11 and Fig. 13, the short-side parting line PS may pass through the main body plate portion center GMC. As shown in each example in Fig. 12 and Fig. 13, the main body plate part GM may be divided along a longitudinal parting line PL extending in the belt guard longitudinal direction LD instead of or in addition to the short side parting line PS. In this case, the main body plate part GM is a pair of separate plate members located on both sides of the longitudinal parting line PL, which are connected to each other by fastening or the like on the longitudinal parting line PL. Specifically, for example, the main body plate part GM may be a pair of separate plate members located on both sides of the longitudinal parting line PL, each of which has a bent part extending to one side of the belt guard depth direction DD on the longitudinal parting line PL, and the bent parts of each plate member may be connected to each other by fastening or the like in a state where they are overlapped on the longitudinal parting line PL. As shown in each example in Fig. 12 and Fig. 13, the belt guard longitudinal direction LD may pass through the main body plate part center GMC. When the main body plate portion GM is divided on the short-side dividing line PS and / or the long-side dividing line PL as described above, the offset pattern K described in this specification ignores the uneven parts associated with the division (such as the above-mentioned folded parts) and refers only to the pattern that appears due to the unevenness in the depth direction of the belt guard other than that.

[0046] The thickness T of the main body plate part GM (i.e., the thickness of the plate member constituting the main body plate part GM) (FIG. 8) is preferably 0.8 to 1.6 mm, and is preferably, for example, 0.8 mm. In this case, the thickness T of the main body plate part GM is thinner than the thickness of a conventional belt guard, and thus the main body plate part GM and the belt guard G can be made lighter, but the offset pattern K described above ensures that the main body plate part GM and the belt guard G have sufficient strength in the torsional direction. From the same viewpoint, it is preferable that the thickness of each of the plate members constituting the belt guard G is 0.8 to 1.6 mm, and for example, it is preferable that the thickness is 0.8 mm.

[0047] From the viewpoint of improving strength in the torsional direction, the offset amount OS (FIG. 8) between the background portion KB and the shape portion KN in the offset pattern K of the main plate portion GM is preferably 1.3 mm or more, and more preferably 1.5 mm or more. For example, the offset amount OS is preferably 1.6 mm.

[0048] From the viewpoint of improving the strength in the torsional direction, it is preferable that the width W1 (FIG. 4) of the short-side dividing line portion KS is wider. The width W1 of the short-side dividing line portion KS is preferably, for example, 100 mm or more. The width W1 of the short-side dividing line portion KS may be, for example, 150 mm or less. Furthermore, the width W1 of the short-side dividing line portion KS is preferably, for example, 5% or more of the total length of the belt guard longitudinal direction LD of the main body plate portion GM. The width W1 of the short-side dividing line portion KS may be, for example, 7% or less of the total length of the belt guard longitudinal direction LD of the main body plate portion GM. From the viewpoint of improving the strength in the torsional direction, it is preferable that the width W2 (FIG. 4) of each inclined direction dividing line portion KI is wider. The width W2 of the inclined direction dividing line portion KI is preferably, for example, 75 mm or more. The width W2 of the inclined direction dividing line portion KI may be, for example, 100 mm or less. The width W2 of the inclined direction dividing line portion KI is preferably, for example, 4% or more of the total length of the belt guard longitudinal direction LD of the main body plate portion GM. The width W2 of the inclined direction dividing line portion KI may be, for example, 5% or less of the total length of the belt guard longitudinal direction LD of the main body plate portion GM. From the viewpoint of improving the strength in the torsional direction, it is preferable that the maximum value of the width W3 of each lateral outer peripheral portion KR1S (FIG. 4) is approximately equal to the width W1 of the lateral demarcation line portion KS. For example, it is preferable that the maximum value of the width W3 of each lateral outer peripheral portion KR1S is 0.9 to 3.0 times the width W1 of the lateral demarcation line portion KS, and more preferably 1.0 to 1.5 times. Note that the maximum value of the width W3 of the lateral outer peripheral portion KR1S refers to the width of the portion where the width W3 of the lateral outer peripheral portion KR1S is maximum.

[0049] As in the example shown in Figs. 4 to 9, the belt guard G may include a side plate portion GS, a back plate portion GB, and a folded-back plate portion GR in addition to a main plate portion GM.

[0050] The side plate portion GS extends from the outer peripheral edge of the main plate portion GM to a first side DD1 in the belt guard depth direction. The side plate portion GS extends around the entire circumference and is thus annular. The side plate portion GS is configured to cover the outer peripheral side of the belt drive portion D (FIGS. 1 to 3). The presence of the side plate portion GS can further prevent a person or the like from interfering with the belt drive portion D, and can also improve the strength (particularly the strength in the torsional direction). In the example shown in Figures 4 to 9, the side plate portion GS is composed of side plate portions GSa, GSb, GSc, GSd, GSe, GSf, GSg, and GShi extending from the outer peripheral edge portions GMa, GMb, GMC, GMd, GMe, GMf, GMg, and GMh of the main plate portion GM respectively toward the first side DD1 in the depth direction of the belt guard.

[0051] The back plate portion GB extends from the edge of the side plate portion GS on the first side DD1 in the belt guard depth direction toward the inner periphery (FIGS. 7 and 9). It is preferable that the back plate portion GB is configured to be located closer to the first side DD1 in the belt guard depth direction DD than the belt drive portion D (FIG. 2). However, it is preferable that the back plate portion GB is located only on the outer periphery side of the belt drive portion D, so as not to cover the first side DD1 in the belt guard depth direction of the belt drive portion D. For example, it is preferable that the back plate portion GB of the belt guard G is located only on the outer periphery side of the multiple shaped portions KN of the offset pattern K on the projection plane in the belt guard depth direction DD. The back plate portion GB makes it easier for an operator to grasp the belt guard G when attaching or detaching the belt guard G to the blower main body portion F, and also improves strength (especially strength in the torsional direction). In the example shown in Figures 4 to 9, the back plate portion GB is composed of back plate portions GBa, GBb extending inward from the edge of the belt guard's depth direction first side DD1 at side plate portions GSa, GSb, respectively, a back plate portion GBc extending inward from the edge of the belt guard's depth direction first side DD1 at side plate portions GSe, GSc, GSf, and a back plate portion GBd extending inward from the edge of the belt guard's depth direction first side DD1 at side plate portions GSg, GSd, GSh. However, the back plate portion GB is not necessary.

[0052] The folded plate portion GR is folded back from the inner peripheral edge of the back plate portion GB toward the second side DD2 in the belt guard depth direction and extends toward the outer peripheral side (FIGS. 7 and 9). The folded plate portion GR can be formed, for example, by hemming the inner peripheral end portion of the back plate portion GB during the manufacture of the belt guard G. The presence of the folded plate portion GR prevents an operator from injuring his or her hands when touching the inner edge of the back plate portion GB, for example, when attaching or detaching the belt guard G to the blower main body portion F, and also improves the strength of the belt guard G (especially the strength in the torsional direction).In addition, deformation and unevenness of the ends of the plate members that make up the belt guard G can be suppressed, thereby improving the appearance. However, the folding plate portion GR may be omitted.

[0053] The belt guard G may be formed by connecting a plurality of members GPa to GPC, which are separately constructed from one another, by fastening them together, as in the example shown in Fig. 6. As a specific fastening method, riveting is preferable. Since multiple components GPa to GPc are connected together by fastening, welding is not required, which means there is no need to remove spatter (particles that fly off and harden during welding).In addition, since no fumes are generated, the work environment is improved. For example, as shown in the example of Fig. 6, the belt guard G may be composed of three members, a central member GPa and a pair of end members GPb, GPc located on both sides of the central member GPa in the belt guard extending direction LD. In the example of Fig. 6, the central member GPa and the end members GPb, GPc are each provided with a plurality of fastening holes (more specifically, in the example of the figure, riveting holes) H. The end members GPb, GPc each have a plurality of extension piece parts GPE configured to be overlapped with the central member GPa, and each of these plurality of extension piece parts GPE is provided with one or a plurality of fastening holes H. Then, in a state in which the fastening holes H of the central member GPa and the fastening holes H of the end members GPb, GPc are overlapped, fastening (riveting in the example of the figure) is performed at each fastening hole H, and the portion becomes a fastened portion (fastened portion) R (Fig. 5). In the example of Fig. 6, the central member GPa is composed of a main plate portion GM, side plate portions GSa, GSb, back plate portions GBa, GBb, and folded plate portions GRa, GRb. The end member GPb is composed of side plate portions GSe, GSc, GSf, back plate portion GBc, folded plate portion GRc, and multiple extension piece portions GPE. The end member GPc is composed of side plate portions GSg, GSd, GSh, back plate portion GBd, folded plate portion GRd, and multiple extension piece portions GPE. By constructing the belt guard G from multiple members GPa to GPC in this way, it is possible to reduce materials by simplifying the components, to facilitate assembly, and to facilitate parts management. In addition, the end members GPb and GPC can be constructed from members of the same shape, so it is possible to standardize the members. Furthermore, while the central member GPa can be changed depending on the overall length of the belt guard G, the same end members GPb and GPc can be used, so design can be simplified. As a result, it is possible to reduce material costs, labor costs, and management costs for the belt-driven blower 1 as a whole. EXAMPLES

[0054] Comparative Examples 1 to 5 and Examples 1 to 4 of the belt guard G were analyzed, and the results are described below. Details of Comparative Examples 1 to 5 and Examples 1 to 4 are as shown in the following Table 1 and FIGS. 14 to 16. In this analysis, a model of the central member GPa (FIG. 6) of the belt guard G was created for each of Comparative Examples 1 to 5 and Examples 1 to 4, and an index value (Hz) indicating strength in the torsional direction (FIG. 17) was obtained by analysis using each model. The results are shown in Table 1. In Table 1, the higher the index value (Hz) indicating strength in the torsional direction, the higher the strength in the torsional direction. In each of these examples, the total length of the main body plate part GM in the belt guard longitudinal direction LD was 2200 mm, the total length of the main body plate part GM in the belt guard lateral direction SD was 700 mm, and the plate thickness T of the main body plate part GM was 1.2 mm. The physical properties of the materials constituting each of these examples were the same. In Comparative Examples 1 and 2, the side plate parts GSa and GSb were flat as shown in FIG. 16(a), while in Comparative Examples 3 to 5 and Examples 1 to 4, the side plate parts GSa and GSb had offset parts GQ offset in the plate thickness direction as shown in FIG. 16(b). Comparative Examples 3 to 5 and Examples 1 to 3 were different from each other only in the offset pattern K, and the other configurations were the same. In comparative examples 1 to 3, as shown in FIG. 14(a), the background portion KB was composed of a first outer peripheral portion KR1 and three short-side dividing line portions KS, between which four fourth shape portions KN4 were defined as multiple shape portions KN. In Comparative Example 4, as shown in Fig. 14(b), the background portion KB is composed of a first outer peripheral portion KR1 and a pair of inclined dividing line portions KI, and between these are defined two second shaped portions KN2 and two fifth shaped portions KN5 as the multiple shaped portions KN. The two fifth shaped portions KN5 are defined between the first outer peripheral portion KR1 and the pair of inclined dividing line portions KI on both sides of the belt guard short side direction SD relative to the main body plate portion center GMC. As shown in FIG. 15(a), Comparative Example 5 had an offset pattern K that was basically the same as the example in FIG. 4 described above, except for the configuration of the pair of short-side outer peripheral portions KR1S of the first outer peripheral portion KR1. In a pair of short-side outer peripheral portions KR1S in Comparative Example 4 (Figure 14(b)) and Comparative Example 5 (Figure 15(a)), the inner edge KR1Sa of each belt guard in the longitudinal direction LD has a non-linear shape that follows the outer peripheral edge of the main body plate portion GM, and more specifically, has a convex bent shape (bent line shape) outward in the longitudinal direction LD of the belt guard. As shown in Figs. 15(b) to 15(d), Examples 1 to 4 basically had the same offset pattern K as the example in Fig. 4 described above.

[0055] [Table 1]

[0056] As can be seen from the results in Table 1, Examples 1 to 4 had higher strength in the torsional direction than Comparative Examples 1 to 5. [Industrial Applicability]

[0057] The belt guard and belt-driven blower of the present invention can be suitably applied to any type of belt-driven blower, and can be particularly suitably applied to belt-driven blowers equipped with a belt guard whose total longitudinal length is approximately 2 m or more. [Explanation of symbols]

[0058] 1: Belt-driven blower, G: Belt guard, GM: Main body plate, K: offset pattern, KI: Diagonal line section, KI1: First inclination direction division line portion, KI2: Second inclination direction division line portion, KIc: Center line of the inclination direction division line, KS: Short side partition line, KSc: Center line of short side partition line, KN: Shape part KN1: 1st shape part, KN2: 2nd shape part, KN3: 3rd shape part, KN4: 4th shape part, KN5: 5th shape part, KR1: 1st outer periphery, KR1S: Short side outer circumference, KR1Sa: The inner edge of the belt guard in the longitudinal direction of the outer periphery in the short direction, KR1Sb: The outer edge of the belt guard in the longitudinal direction of the outer periphery in the short direction, KR1L: Longitudinal outer periphery, KR2: Second outer periphery, KB: Background section, KL: Longitudinal division line, GMC: Main body plate center, GMa, GMb, GMC, GMd, GMe, GMf, GMg, GMh: outer peripheral edge part, GS: Side plate part, GSa, GSb, GSc, GSd, GSe, GSf, GSg, GSH: Side plate parts, GB: Back plate, GBa, GBb, GBc, GBd: Back plate part, GR: Folding plate section, GRa, GRb, GRc, GRd: folded plate parts, GPa: central member (member), GPb, GPc: end members (members); GPE: extension piece, H: Fastening hole, R: Fastening part, PS: Short direction dividing line, LS: Longitudinal parting line, GQ: Offset section, DD: Belt guard depth direction, DD1: Belt guard depth direction 1st side, DD2: Belt guard depth direction second side, SD: Belt guard short direction, SD1: Belt guard short side first side, SD2: Belt guard short side second side, LD: Belt guard longitudinal direction, LD1: Belt guard longitudinal direction 1st side, LD2: Belt guard longitudinal second side, D: Belt drive unit, D1: Impeller side pulley, D2: Motor side pulley D3: Belt, F: Blower body, F1: Bass, F2: Casing, F3: impeller, F4: Impeller shaft, F5: Motor, F6: Motor shaft, J1, J2: Connecting members

Claims

1. A belt guard for a belt-driven blower, comprising: a main body plate portion configured to be disposed on an opposite side of the belt drive portion of the belt drive type blower from the blower main body portion of the belt drive type blower, The main body plate portion has an offset pattern that is expressed by unevenness in the belt guard depth direction, The offset pattern is A background part; A plurality of shaped portions located on either side of the background portion in the belt guard depth direction; It has The background portion is An annular first outer circumferential portion; a pair of inclined dividing line portions each extending in a direction inclined with respect to both the short-side direction of the belt guard and the long-side direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersect with each other on the center of the main body plate portion; A lateral dividing line portion extending in a lateral direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at a center of the main body plate portion; It has the first outer peripheral portion includes a pair of short-side outer peripheral portions that connect the ends of the pair of inclined dividing line portions on both sides of the belt guard in the longitudinal direction and extend in a substantially short-side direction of the belt guard, The pair of outer peripheral portions in the short side direction have inner end edges in the longitudinal direction of the belt guard that extend linearly in the short side direction of the belt guard over the entire length of the inner end edges in the longitudinal direction of the belt guard, The plurality of shaped portions are defined between the first outer circumferential portion, the pair of inclined direction dividing line portions, and the short side direction dividing line portions, The belt guard is a side plate portion extending from an outer peripheral edge of the main body plate portion toward a first side in a belt guard depth direction; A back plate portion extending from an end edge of the side plate portion on a first side in the belt guard depth direction toward an inner peripheral side; It also has A belt guard, wherein, on a projection plane in the depth direction of the belt guard, the back plate portion is located only on the outer circumferential side of the plurality of shaped portions of the offset pattern.

2. A belt guard for a belt-driven blower, comprising: a main body plate portion configured to be disposed on an opposite side of the belt drive portion of the belt drive type blower from the blower main body portion of the belt drive type blower, The main body plate portion has an offset pattern that is expressed by unevenness in the belt guard depth direction, The offset pattern is A background part; A plurality of shaped portions located on either side of the background portion in the belt guard depth direction; It has The background portion is An annular first outer circumferential portion; a pair of inclined dividing line portions each extending in a direction inclined with respect to both the short-side direction of the belt guard and the long-side direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersect with each other on the center of the main body plate portion; A lateral dividing line portion extending in a lateral direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at a center of the main body plate portion; It has the first outer peripheral portion includes a pair of short-side outer peripheral portions that connect the ends of the pair of inclined dividing line portions on both sides of the belt guard in the longitudinal direction and extend in a substantially short-side direction of the belt guard, The pair of outer peripheral portions in the short side direction have inner end edges in the longitudinal direction of the belt guard that extend linearly in the short side direction of the belt guard over the entire length of the inner end edges in the longitudinal direction of the belt guard, The plurality of shaped portions are defined between the first outer circumferential portion, the pair of inclined direction dividing line portions, and the short side direction dividing line portions, The offset pattern further has an annular second outer periphery, the second outer periphery is defined between the background portion and an outer periphery edge of the main body plate portion, and extends entirely around a center of the main body plate portion; The second outer peripheral portion is located on the same side as the plurality of shaped portions in the belt guard depth direction with respect to the background portion.

3. A belt guard for a belt-driven blower, comprising: a main body plate portion configured to be disposed on an opposite side of the belt drive portion of the belt drive type blower from the blower main body portion of the belt drive type blower, The main body plate portion has an offset pattern that is expressed by unevenness in the belt guard depth direction, The offset pattern is A background part; A plurality of shaped portions located on either side of the background portion in the belt guard depth direction; It has The background portion is An annular first outer circumferential portion; a pair of inclined dividing line portions each extending in a direction inclined with respect to both the short-side direction of the belt guard and the long-side direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersect with each other on the center of the main body plate portion; A lateral dividing line portion extending in a lateral direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at a center of the main body plate portion; It has the first outer peripheral portion includes a pair of short-side outer peripheral portions that connect the ends of the pair of inclined dividing line portions on both sides of the belt guard in the longitudinal direction and extend in a substantially short-side direction of the belt guard, The pair of outer peripheral portions in the short side direction have inner end edges in the longitudinal direction of the belt guard that extend linearly in the short side direction of the belt guard over the entire length of the inner end edges in the longitudinal direction of the belt guard, The plurality of shaped portions are defined between the first outer circumferential portion, the pair of inclined direction dividing line portions, and the short side direction dividing line portions, The belt guard has a total length in the longitudinal direction of 1.0 m or more and 3.0 m or less, and a total length in the lateral direction of 30 cm or more and 80 cm or less, The width W1 of the short-side dividing line portion is 100 mm or more and 150 mm or less, The width W2 of the inclined direction dividing line portion is 75 mm or more and 100 mm or less, The maximum value of the width W3 of each of the short-side outer peripheral portions is 0.9 to 3.0 times the width W1 of the short-side dividing line portion.

4. The belt guard according to any one of claims 1 to 3, wherein each of the plurality of shaped portions has a substantially triangular shape.

5. The background portion is a longitudinal dividing line portion extending in the longitudinal direction of the belt guard, both ends of which are connected to the first outer circumferential portion, and which intersects with the pair of inclined dividing line portions at a center of the main body plate portion; and The belt guard according to any one of claims 1 to 3, wherein the plurality of shaped portions are partitioned between the first outer peripheral portion, the pair of inclined direction dividing line portions, the short side direction dividing line portions, and the longitudinal direction dividing line portions.

6. A folded plate portion folded back from the inner peripheral edge of the back plate portion toward the second side in the belt guard depth direction and extending toward the outer peripheral side, 10. The belt guard of claim 1 further comprising:

7. The belt guard according to any one of claims 1 to 3, wherein the belt guard has a substantially octagonal shape in a plan view.

8. The belt guard according to any one of claims 1 to 3, wherein the main body plate portion has a plate thickness of 0.8 to 1.6 mm.

9. The belt guard described in any one of claims 1 to 3, wherein the belt guard is formed by connecting a plurality of components constructed separately from each other by fastening them together.

10. The belt guard as described in claim 9, wherein the belt guard is composed of three members: a central member and a pair of end members located on either side of the central member in the longitudinal direction of the belt guard.

11. The belt guard according to any one of claims 1 to 3, wherein the belt guard is formed by connecting a plurality of members formed separately from one another by riveting.

12. A belt guard according to any one of claims 1 to 3; The belt drive unit; The blower main body, A belt-driven blower.

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