Air-cooling hydraulic device

Abstract

To provide an air-cooling hydraulic device comprising a hood for improving cooling efficiency of a hydraulic unit by efficiently processing air on the side of a radiator by means of a cooling fan in a configuration where the cooling fan is mounted to a motor shaft of a motor.SOLUTION: An air-cooling hydraulic device comprises a hydraulic pump, a motor which drives the hydraulic pump, an oil tank, a radiator which cools a drain or a return oil returning to the oil tank, a cooling fan which is mounted to a motor shaft of the motor and disposed between the motor and the radiator, and a hood which covers the cooling fan. The hood is configured by including a rectangular part and a cylindrical part, the rectangular part encloses an entire ventilation portion on a surface of the radiator on the side of the motor, and the cylindrical part includes the cooling fan. A diameter of the cylindrical part is slightly larger than a nominal diameter of the cooling fan, and an opening edge of the cylindrical part is provided so as to be opposed to a surface of the motor on the side of the radiator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an air-cooled hydraulic system, and more particularly to an improvement in a hydraulic system in which a radiator is cooled by airflow from a cooling fan for an electric motor that drives a hydraulic pump. [Background technology]

[0002] Water-cooled and air-cooled coolers are used to prevent the temperature of hydraulic oil in hydraulic systems from rising. For example, Patent Document 1 discloses a configuration using an air-cooled cooler. In the air-cooled hydraulic system described in Patent Document 1, the surface of a radiator is installed close to the cooling fan of the electric motor that drives the pump, and the radiator is cooled by the airflow from the cooling fan of the electric motor.

[0003] Furthermore, in Patent Document 2, the applicant discloses an air-cooled hydraulic unit in which a hood is provided between the fan cover of the electric motor and the radiator. One end of this hood has a rectangular opening that opens to the rectangular radiator surface of the air-cooled cooler, and the other end has a hole into which the tip of the fan cover of the electric motor is inserted. The applicant states that this makes it possible to provide an air-cooled hydraulic unit that, even with a rectangular radiator, has a simple structure, can use conventional coolers and electric motors, has good thermal efficiency, and can demonstrate performance according to its cooling capacity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 49-50804 [Patent Document 2] Patent No. 3672153 Summary of the Invention [Problem to be solved by the invention]

[0005] The air-cooled hydraulic system described in Patent Document 2 is premised on the use of a cooling fan for the purpose of cooling the electric motor. Therefore, the main role of the cooling fan is to cool the electric motor, and cooling the radiator is secondary.

[0006] However, depending on the use of the hydraulic unit, the efficiency of the electric motor, and the heat resistance of the electric motor, it does not necessarily have to be configured to primarily cool the electric motor. In other words, since improved cooling performance of the radiator is required, it is effective to increase the relative importance of radiator cooling by using a cooling fan attached to the motor shaft.

[0007] Therefore, an object of the present invention is to provide an air-cooled hydraulic system equipped with a hood that has a cooling fan attached to the motor shaft of an electric motor, and that efficiently processes air on the radiator side using the cooling fan, thereby improving the cooling efficiency of the hydraulic unit. [Means for solving the problem]

[0008] In order to solve the above problems, a typical configuration of an air-cooled hydraulic device according to the present invention comprises a hydraulic pump, an electric motor that drives the hydraulic pump, an oil tank, a radiator that cools the drain or return oil that returns to the oil tank, a cooling fan that is attached to the motor shaft of the electric motor and is arranged between the electric motor and the radiator, and a hood that covers the cooling fan, the hood being configured to include a rectangular portion and a cylindrical portion, the rectangular portion surrounding the entire ventilation portion on the electric motor side surface of the radiator, the cylindrical portion containing the cooling fan, the diameter of the cylindrical portion being slightly larger than the nominal diameter of the cooling fan, and the opening edge of the cylindrical portion being arranged so as to face the radiator side surface of the electric motor.

[0009] The cooling fan is configured to send air from the radiator side toward the motor side, and it is preferable that the opening side of the cylindrical portion is provided with gaps all over to allow the air sent to the motor side to pass through, and that a finger guard is attached to prevent fingers from entering through the opening of the cylindrical portion. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an air-cooled hydraulic device equipped with a hood that can provide high cooling efficiency, particularly for the radiator, in a configuration in which a cooling fan is attached to the motor shaft of the electric motor of a single-rotation pump. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view of an air-cooled hydraulic device according to an embodiment of the present invention. FIG. [Figure 2] FIG. 1 is a perspective view of an air-cooled hydraulic system. [Figure 3] FIG. [Figure 4] FIG. 2 is an exploded perspective view from the electric motor to the radiator. [Figure 5] 1 illustrates parts of an embodiment of an air-cooled hydraulic system. FIG. [Figure 6] FIG. 10 is an analysis diagram of a fluid simulation when the diameter of the cylindrical portion is changed. [Figure 7] FIG. 10 is an analysis diagram of a fluid simulation when the length of the cylindrical portion is changed. [Figure 8] This is an analysis diagram of a fluid simulation when air is discharged from a cooling fan to a radiator. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown or described.

[0013] Fig. 1 is a side view of an air-cooled hydraulic system 100 according to an embodiment of the present invention, with Fig. 1(a) being an overall configuration diagram and Fig. 1(b) being a diagram omitting a hood and finger guards. Fig. 2 is a perspective view of the air-cooled hydraulic system, with Fig. 2(a) being a perspective view seen from the hydraulic pump 120 side and Fig. 2(b) being a perspective view seen from the radiator side.

[0014] In the air-cooled hydraulic system 100, an electric motor 130 assembled integrally with a hydraulic pump 120 is fixed on the top lid of an oil tank 110 that stores hydraulic oil. When the electric motor 130 operates to drive the hydraulic pump 120, the hydraulic oil is discharged. As shown in FIG. 2(a), the electric motor 130 has a generally cylindrical body as a whole. One end of a motor shaft 130a of the electric motor 130 is connected to the hydraulic pump 120, and as shown in FIG. 1(b), a cooling fan 150 is attached to the other end. That is, the cooling fan 150 is directly attached to the motor shaft 130a of the electric motor 130, and when the electric motor 130 drives the hydraulic pump 120, the cooling fan 150 also rotates. The cooling fan 150 is located between the radiator 140 and the electric motor 130. As will be described later, a configuration in which the cooling fan 150 rotates to draw air from the radiator 140 toward the electric motor 130 (suction) is more effective than a configuration in which the air flows in the opposite direction (exhaust).

[0015] The radiator 140 is disposed on the opposite side of the electric motor 130 from the hydraulic pump 120. The radiator 140 cools the drainage generated during operation and returns it to the oil tank 110. The radiator 140 has a simple laminated structure and is a rectangular radiator as shown in FIG. 2(b).

[0016] As can be seen by comparing FIG. 1( a ) and FIG. 1( b ), a hood 160 that covers the cooling fan 150 is attached between the radiator 140 and the electric motor 130 .

[0017] Figure 3 is a diagram for explaining the hood 160, where Figure 3(a) is a three-sided view and Figure 3(b) is a perspective view. Figure 4 is an exploded perspective view from the electric motor to the radiator.

[0018] The hood 160 is composed of a rectangular portion 170 and a cylindrical portion 180. The rectangular portion 170 of the hood 160 has approximately the same dimensions in the height and width directions as the ventilation portion of the rectangular radiator 140. The width direction is a direction perpendicular to the direction from the electric motor 130 toward the radiator 140. In other words, the rectangular portion 170 is provided so as to surround the entire ventilation portion on the surface of the radiator 140 facing the electric motor 130. The rectangular portion 170 is provided with a bracket 172 for mounting to the radiator. By fitting the bracket 172 into the radiator 140, the rectangular portion 170 is positioned in close contact with the radiator 140. This allows the airflow generated by the cooling fan 150 to pass over the entire surface of the radiator 140, thereby achieving high cooling efficiency.

[0019] The cylindrical portion 180 of the hood 160 contains the cooling fan 150. In each drawing, the diameter of the cooling fan 150 is larger than the diameter of the electric motor 130. The diameter of the cylindrical portion 180 is slightly larger than the nominal diameter (the outer edge of the rotating cooling fan) of the cooling fan 150 and is sized to face the surface of the electric motor 130 on the radiator 140 side (see FIG. 1(a)). In other words, the opening of the cylindrical portion 180 facing the electric motor 130 faces the end (or surface) of the electric motor 130 on the radiator 140 side and is close enough to that end to allow the finger guard 190 to be placed thereon (the opening end of the cylindrical portion 180 is close enough to the outer peripheral surface of the electric motor 130 so as not to overlap (cover) it). This prevents the air blown out from the cooling fan 150 from flowing back toward the radiator 140 (the intake side of the radiator).

[0020] Furthermore, the above explanation regarding the diameter of cylindrical portion 180 can be restated as meaning that the height of the opening of cylindrical portion 180 is slightly higher than the height of the body of electric motor 130 when attached to the unit. This height (diameter) is determined according to the size of cooling fan 150. As a result, electric motor 130 does not block the opening of cylindrical portion 180 and does not impede the flow of air, thereby achieving high cooling efficiency.

[0021] The opening of the cylindrical portion 180 is provided with gaps throughout to allow air sent to the electric motor 130 to pass through, and a finger guard 190 is attached to prevent fingers from entering through the opening. The finger guard 190 has a mesh-like structure with wires arranged at predetermined intervals. The wires are preferably spaced 4 mm or less apart to prevent fingertip intrusion. This prevents the worker's fingers from touching the cooling fan 150, improving safety. Fingertip intrusion can also be prevented by having the cylindrical portion 180 cover the radiator side of the body of the electric motor 130. However, such a configuration to protect fingertip is known to impede airflow, as described below, resulting in a deterioration of the radiator's cooling performance. Therefore, in this embodiment, such a finger guard is employed to prevent fingertip intrusion while allowing smooth airflow.

[0022] Furthermore, if the outer diameter of finger guard 190 is equal to or greater than the outer diameter of cylindrical portion 180, it is possible to prevent the worker's fingers from touching the edge of cylindrical portion 180, thereby further improving safety.

[0023] In this embodiment, the finger guard feet 192 are configured to attach to the bolts 132 of the motor 130. However, the finger guard 190 may also be configured to attach to the cylindrical portion 180 of the hood 160.

[0024] 5A and 5B show the components of an embodiment of an air-cooled hydraulic system, with Fig. 5A showing the hood 160 and Fig. 5B showing the distance between the radiator 140 and the electric motor 130 and the cooling fan 150. The numerical values ​​described below are merely examples for explaining the magnitude relationships and do not limit the present invention.

[0025] In one example of this embodiment shown in Figure 5(a), the length L1 of the rectangular portion 170 of the hood 160 is 20 to 23% shorter than the length L2 of the cylindrical portion 180. Furthermore, the length L1 of the rectangular portion 170 is approximately 42 to 44% of the overall length L3 of the hood 160, and the length L2 of the cylindrical portion 180 is approximately 56 to 58%. Note that these lengths are the lengths in the direction from the electric motor 130 toward the radiator 140 as shown in Figure 1 (the left-right direction in Figure 1; the same applies below).

[0026] The inner diameter Φ1 of the cylindrical portion 180 is approximately 20 to 21% larger than the diameter Φ2 of the cooling fan. The diameter of this cooling fan is configured to cover the entire ventilation portion of the surface of the radiator 140 facing the electric motor 130. To balance between increasing the diameter of the cooling fan and shortening the length L2 of the cylindrical portion 180 (preventing the air-cooled hydraulic device from becoming larger), the height of the cylindrical portion 180 is set based on the height of the rectangular portion 170. This is because if the difference in height between the cylindrical portion 180 and the rectangular portion 170 is large, a taper is required to fill the difference, which increases the length of the cylindrical portion 180. As described above, the rectangular portion 170 of the hood 160 is configured to cover the ventilation portion of the radiator 140. Therefore, taking into consideration that the cooling fan will fit inside the cylindrical portion 180, the diameter of the cooling fan is set to a size that covers the entire ventilation portion of the radiator 140. The inner diameter Φ1 of the cylindrical portion 180 is configured to be not too large compared to the diameter Φ2 of the cooling fan.

[0027] Furthermore, length L2 of cylindrical portion 180 of hood 160 is 5 to 6.5% shorter than thickness L4 (length in the above direction) of the cooling fan. Furthermore, length L3 of hood 160 is approximately 4 to 5% shorter than the distance between radiator 140 and electric motor 130 in FIG.

[0028] That is, the inner diameter Φ1 of the cylindrical portion of hood 160 is set to be approximately 21.5 to 22.5% larger than the outer diameter Φ3 of the radiator-side end face of the body of electric motor 130. Furthermore, in FIG. 5 , the length L3 of hood 160 is approximately 4 to 5% shorter than the distance L5 between radiator 140 and electric motor 130, and as a result, the distance from the opening of cylindrical portion 180 to electric motor 130 is set to be approximately 5 to 6% of the distance L5 between radiator 140 and electric motor 130.

[0029] 6A and 6B are diagrams illustrating analysis of a fluid simulation when the diameter of the cylindrical portion is changed, where Fig. 6A is a diagram illustrating Comparative Example 1, and Fig. 6B is a diagram illustrating the above-mentioned Example.

[0030] In Comparative Example 1 shown in FIG. 6(a), the outer diameter of the cylindrical portion 180 is increased by approximately 2.9% compared to the Example (FIG. 6(b)). Because the gap between the hood 160 and the cooling fan 150 is increased, the vortex swirling inside the hood 160 is larger. This reduces the amount of air passing through the radiator 140. Furthermore, because the workload of the cooling fan 150 is reduced, the drive torque is reduced. In addition, the airflow reaching the side of the electric motor 130 is shortened.

[0031] From FIG. 6(a), it can be seen that if the diameter of the cylindrical portion 180 is not too larger than the diameter of the cooling fan 150, the air on the radiator 140 side can be efficiently sucked in.

[0032] Fig. 7 is a diagram illustrating an analysis of a fluid simulation when the length of the cylindrical portion 180 is changed. Fig. 7(a) is a diagram illustrating Comparative Example 2, Fig. 7(b) is a diagram illustrating Comparative Example 3, Fig. 7(c) is a diagram illustrating the above embodiment, and Fig. 7(d) is a diagram illustrating Comparative Example 4.

[0033] In Comparative Example 2 shown in FIG. 7(a), the length is shorter than the cylindrical portion 180 of the embodiment (FIG. 7(c)), and the entire length of the cooling fan 150 is not covered. The difference is 58.6% shorter than that of the embodiment. In Comparative Example 3 shown in FIG. 7(b), the length is shorter than the cylindrical portion 180 of the embodiment (FIG. 7(c)), and the difference is 29.3% shorter than that of the embodiment. In Comparative Examples 2 and 3, a flow occurs in which the air blown out from the cooling fan 150 returns to the radiator 140 side (the intake side of the radiator).

[0034] In Comparative Example 4 shown in FIG. 7(d), the length of the cylindrical portion is 58.6% longer than that of the embodiment (FIG. 7(c)). In Comparative Example 4, the cylindrical portion 180 covers the end of the electric motor 130. If the cylindrical portion 180 of the hood 160 is made longer, the gap between the cylindrical portion 180 and the electric motor becomes smaller, and the load on the downstream side of the cooling fan 150 increases, so the amount of air passing through the radiator 140 decreases. In addition, the workload of the cooling fan 150 increases, so the drive torque increases.

[0035] 7(a) and 7(b), it can be seen that the length of the cylindrical portion 180 is preferably such that the opening of the cylindrical portion 180 on the electric motor 130 side is close to the electric motor 130. Also, it can be seen from FIG. 7(d) that the length of the cylindrical portion 180 is preferably such that it does not overlap with the end of the electric motor 130.

[0036] That is, the opening of cylindrical portion 180 facing electric motor 130 faces the end (or surface) of electric motor 130 on the radiator side, and is close enough to allow a finger guard to be disposed thereon, thereby preventing the air blown out from cooling fan 150 from flowing back toward radiator 140 (the intake side of the radiator). Furthermore, because cylindrical portion 180 does not overlap (cover) electric motor 130, it is possible to prevent a decrease in the amount of air passing through radiator 140 and an increase in the drive torque of cooling fan 150.

[0037] Fig. 8 is a diagram of a fluid simulation analysis in the case where air is discharged from the cooling fan to the radiator. Fig. 8(a) is a diagram showing the above-mentioned embodiment, and Fig. 8(b) is a diagram showing Comparative Example 5. In contrast to the embodiment shown in Fig. 8(a), Comparative Example 5 shown in Fig. 8(b) is configured such that the orientation of the cooling fan 150 is reversed to reverse the direction of the airflow, and air flows toward the radiator 140 in the opposite direction from the electric motor 130.

[0038] 8(b), it can be seen that the airflow swirls between the cooling fan 150 and the radiator 140, preventing it from passing through the radiator 140. This results in a significant decrease in the amount of air passing through the radiator. This shows that a configuration in which the cooling fan 150 rotates to draw air from the radiator 140 toward the electric motor 130 (intake) is more effective than a configuration in which the cooling fan 150 rotates to draw air in the opposite direction (exhaust).

[0039] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0040] The present invention can be used as an air-cooled hydraulic device provided with a cooling fan between an electric motor and a radiator. [Explanation of symbols]

[0041] 100...air-cooled hydraulic device, 110...oil tank, 120...hydraulic pump, 130...electric motor, 130a...motor shaft, 132...bolt, 140...radiator, 150...cooling fan, 160...hood, 170...rectangular portion, 172...bracket, 180...cylindrical portion, 190...finger guard, 192...foot of finger guard

Claims

1. A hydraulic pump, an electric motor that drives the hydraulic pump; Oil tank and a radiator for cooling the drain or return oil returning to the oil tank; a cooling fan attached to a motor shaft of the electric motor and disposed between the electric motor and the radiator; a hood that covers the cooling fan, The hood is configured to include a rectangular portion and a cylindrical portion, the rectangular portion surrounds the entire ventilation portion on the surface of the radiator facing the electric motor, an air-cooled hydraulic device characterized in that the cylindrical portion contains the cooling fan, the diameter of the cylindrical portion is slightly larger than the nominal diameter of the cooling fan, and the opening edge of the cylindrical portion is arranged so as to face the radiator side surface of the electric motor.

2. The cooling fan is configured to send air from the radiator side toward the electric motor side, 2. The air-cooled hydraulic device according to claim 1, wherein a gap is provided on the entire opening side of the cylindrical portion to allow air sent to the electric motor side to pass through, and a finger guard is attached to prevent fingers from entering through the opening of the cylindrical portion.

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