Cooling structure of working machine

Abstract

To provide a cooling structure of an electric component which efficiently cools the electric component with a relatively simple structure.SOLUTION: An engine base 15 is provided on a vehicle body 5, an engine E is mounted on the front side of the vehicle body 5 on the upper surface of the engine base 15, and a generator 25 is mounted on the rear side of the engine E at the substantially center in the longitudinal direction of the vehicle body 5. In a working machine in which an electrical component 104 is mounted on a side or a rear side of a generator 25 and a cover 29 is provided above the generator 25 and the electrical component 104, the generator 25 includes a rotation shaft 99 protruding upward from an upper surface and a power generation shaft 56 protruding downward from a lower surface, the rotation shaft 99 and the power generation shaft 56 are configured to rotate in conjunction with each other, a fan 97 is attached to the rotation shaft 99, the power generation shaft 56 is rotated by driving of an engine E to rotate the fan 97, and cooling air 100 is generated downward and in an outer peripheral direction of the fan 97.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a cooling structure for a work machine equipped with electrical components such as a generator, a battery, and a controller. [Background technology]

[0002] A remote-controlled mower capable of mowing even on steep slopes has been known, as disclosed in Patent Document 1 below. This mower is driven by a motor and is equipped with a battery to drive the motor and an alternator as a generator to charge the battery. It is also equipped with a controller to control the motor and other components, and is covered from above with a cover to protect these electrical components.

[0003] Furthermore, as disclosed in Patent Document 2 below, a technique is known in which electrical components that generate heat during use are cooled by a fan to prevent problems caused by overheating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-005554 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-263921 Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration of the remote-controlled brush cutter described in Patent Document 1, the engine, alternator, battery, etc. are mounted in a limited space on the engine base, so there is not enough clearance between each piece of equipment, and there is room for consideration regarding the disposal of exhaust heat and cooling. Furthermore, because heat-generating elements such as the alternator, battery, and controller are covered from above, there is the inconvenience of heat being easily trapped inside the cover. Other issues include the engine's drive being transmitted by a belt, and because this transmission is performed below the engine base, heat is difficult to dissipate, causing an increase in the ambient temperature and reducing the durability of the belt.

[0006] Furthermore, when cooling each electrical component with a fan, it is difficult to provide a separate fan due to space and cost constraints, and there is also the inconvenience of having to secure a separate power transmission to drive the fan.

[0007] In view of the above-mentioned problems, an object of the present invention is to provide a cooling structure for a work machine that efficiently cools various electrical components mounted on the work machine. [Means for solving the problem]

[0008] The invention described in claim 1 is a cooling configuration for a work machine having an engine base 15 on a vehicle body 5, an engine E mounted on the upper surface of the engine base 15 at the front of the vehicle body 5, a generator 25 mounted rearward of the engine E and approximately in the center of the vehicle body 5 in the fore-and-aft direction, electrical equipment 104 mounted to the side or rear of the generator 25, and a cover 29 provided above the generator 25 and the electrical equipment 104, wherein the generator 25 has a rotating shaft 99 that protrudes upward from its upper surface and a generating shaft 56 that protrudes downward from its lower surface, the rotating shaft 99 and the generating shaft 56 being configured to rotate in conjunction with each other, a fan 97 attached to the rotating shaft 99, the generating shaft 56 being rotated by the drive of the engine E to rotate the fan 97, and cooling air 100 being generated below and in the outer circumferential direction of the fan 97.

[0009] Furthermore, the invention described in claim 2 provides a cooling configuration for a work machine in which at least a portion not covered by the cover 29 is provided above the fan 97 .

[0010] In addition, the invention described in claim 3 is configured such that the engine E has a drive shaft 11 that protrudes below the engine base 15, and the drive shaft 11 and a generator shaft 56 that protrudes below the engine base from the underside of the generator 25 are configured to be capable of belt transmission, and a ventilation hole 105 is provided on the upper surface of the engine base 15 through which cooling air 100 generated downward by the fan 97 passes to the underside of the engine base 15. [Effects of the Invention]

[0011] According to the invention described in claim 1, the generator 25 has a rotating shaft 99 protruding upward from its upper surface and a generating shaft 56 protruding downward from its lower surface. The rotating shaft 99 and the generating shaft 56 are configured to rotate in conjunction with each other. A fan 97 is attached to the rotating shaft 99. The generating shaft 56 rotates when driven by the engine E, rotating the fan 97 and generating cooling air 100 below and around the fan 97. This eliminates the need for a separate power transmission, thereby suppressing cost increases. Furthermore, the cooling air generated below the fan 97 flows along the wall surface of the generator 25, thereby efficiently cooling the generator 25. Furthermore, the cooling air generated below or around the fan 97 can simultaneously cool electrical components 104 arranged around the generator 25, eliminating the need for separate cooling means for the electrical components 104. Additionally, the cooling air 29 generated in the outer circumferential direction stirs the air within the cover 29, thereby lowering the ambient temperature around the electrical components 104 and suppressing temperature increases in the electrical components 104.

[0012] The invention described in claim 2 is configured such that at least a portion of the fan 97 is not covered by the cover 29. Therefore, even if the temperature inside the cover 29 rises due to heat generated by the electrical equipment 104, the fan 97 can take in outside air from the portion not covered by the cover 29, thereby preventing a decrease in the cooling performance of the generator 25 and the electrical equipment 104 due to a rise in temperature inside the cover 29.

[0013] In the invention described in claim 3, the engine E has a drive shaft 11 that protrudes below the engine base 15, and the drive shaft 11 and the generator shaft 56 that protrudes below the engine base from the underside of the generator 25 are configured to be capable of belt transmission, and the upper surface of the engine base 15 is provided with ventilation holes 105 through which cooling air 100 generated below the fan 97 can escape to the underside of the engine base 15.This makes it possible to send the cooling air 100 to the underside of the engine base 15, where air escapes poorly and heat tends to stagnate, and reduces the ambient temperature of the transmission belt stretched between the drive shaft 11 and the generator shaft 56, thereby improving the durability of the belt. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. [Figure 2] FIG. 10 is a partial side view showing the change in the belt transmission mechanism caused by the lifting and lowering of the mowing deck. [Figure 3] FIG. 4 is a side view of the mower showing the attachment state of the mowing deck by the parallel links and the lifting and lowering operation. [Figure 4] FIG. 4 is a plan view of the brush cutter showing the belt transmission mechanism of the blade shaft. [Figure 5] FIG. 4 is a partial plan view showing a belt transmission mechanism and an operating mechanism of the mowing clutch. [Figure 6] FIG. 2 is a plan view of the brush cutter showing the generator transmission mechanism. [Figure 7] FIG. 4 is a front view showing the tilting and rotating state of the engine relative to the vehicle body when traveling on an inclined surface. [Figure 8] FIG. 2 is a plan view showing the cooling configuration using fans on the top of the generator. DETAILED DESCRIPTION OF THE INVENTION

[0015] As shown in the drawings, the brush cutter is equipped with a pair of left and right travel crawlers 4 made primarily of rubber, and is mounted at the upper rear end of the vehicle body 5. The travel motor M that drives the crawlers 4, a transmission case 22, and two controllers 23 (top and bottom) for traveling, mowing, and other operations are mounted at the front end. The front end is equipped with an engine E for driving the blade shaft 2 of the mowing deck 3. The front and rear center sections are equipped with a battery 24a for starting the engine E, a fuel tank 26, a battery 24b for driving the motor M, a generator 25 for charging the battery 24b, and a rectifier box 101. A fan 97 that operates in conjunction with the generator 25 is mounted on the top surface of the generator 25 and is covered from above by a fan cover 98. Guard frames 28 are mounted at the front and rear of the upper section of the vehicle body 5, forming an arch shape and covering guard pipes 27 at the front and rear ends and the middle section of the vehicle body 5. A cover 29 is provided to protect the upper sides of the various mounted equipment.

[0016] The crawlers 4 are hung on end rollers 32, intermediate rollers 33, and a drive sprocket 34 at the rear end, which are arranged in the front-to-rear direction of left and right track frames 31 attached to support legs 30 that stand upright from both the left and right ends of the vehicle body 5.The left and right traveling motors M transmit rotation of the sprocket shafts 35 via transmission gears in the transmission case 22, thereby rotating the left and right crawlers 4 and enabling the vehicle to travel or steer.

[0017] At the bottom of the vehicle body 5, at the interval (tread portion) between the right crawlers 4, 4, a mowing deck 3, on which a blade shaft 2 of a blade 1 for cutting grass is mounted, is pivotally and detachably attached to the rear ends of parallel links 8, 9 that move up and down by link shafts 36, 37. The front ends of these parallel links 8, 9 are rotatable about lateral link shafts 6, 7 that are attached to bearing brackets formed at the front ends of both the left and right sides of the vehicle body 5. The rear ends of the four left and right parallel links 8, 9 are pivotally attached by link shafts 36, 37 to the rear ends of the four left and right parallel links 8, 9, and the mowing deck 3 is raised and lowered, maintaining a position parallel to the ground to be mowed, via lift links 39, by the rotation of a lift arm 38 that is rotated by the extension and contraction of an electric cylinder 50. At the highest height of the mowing deck 3, the upper surface of the ceiling of the mowing deck 3 is close to the bottom of the vehicle body 5, and is set to be at the upper limit of the mowing height. Furthermore, when the mowing deck 3 is lowered to its lowest height, the mowing height of the grass cut by the blade 1 rotating inside the mowing deck 3 is at its lowest position, and if gauge wheels are attached to the front and rear ends of the mowing deck 3, this minimum mowing height position can be maintained on the ground. Furthermore, guard chains 102 are attached to the frame at the front and rear of the mowing deck 3. The guard chain 102 has a rubber plate on the mowing deck 3 side, and a chain hanging on the outside so as to follow the rubber plate, which can effectively prevent stones and other objects from flying about that are forcefully ejected from the mowing deck 3 during mowing work.

[0018] The mowing deck 3 has a vertical blade shaft 2 rotatably mounted in the center, and the center of a blade stay 40, with the blade 1 disposed on the outer periphery, is attached to the lower end of this blade shaft 2. On the upper side of the mowing deck 3, a blade pulley 17 in the form of a V-pulley is attached to the upper end of the blade shaft 2, which engages with a mowing belt 19 made of a V-belt with a V-shaped cross section and guides its rotation.

[0019] A counter shaft 14 is rotatably erected above the mowing deck 3, just behind the blade shaft 2 and parallel to the blade shaft 2, and a V-pulley-type counter pulley 13 is provided on this counter shaft 14, with an upper counter pulley 13a at its upper end and a lower pulley 21 at its lower end. A V-belt-type mowing belt 19 is stretched between the lower pulley 21 of the counter shaft 14 and the blade pulley 17 of the front blade shaft 2, and power transmission from the counter shaft 14 to the blade shaft 2 can be switched on and off by tensioning and loosening a tension pulley 18 on the rotating outer periphery of the mowing belt 19. A clutch arm 41 of the tension pulley 18 is pivotally mounted on a pivot shaft 42 on the upper surface of the mowing deck 3 at the outer periphery of the lower pulley 21, and an operating wire 43 connected to this clutch arm 41 is connected to an operating arm 45 which is rotated about an arm shaft 46 by an electrically extended and retracted mowing clutch 20 and an electric cylinder 44 for braking the blade shaft 2, and the extension and retraction of this electric cylinder 44 engages and disengages the mowing clutch 20 by the tension pulley 18 (see Figures 4 and 5).

[0020] In addition, a brake arm 47 is rotatably mounted around an arm shaft 48 on the upper surface of the mowing deck 3 around the blade pulley 17. The brake arm 47 fits into and slides into the V-groove portion of the blade pulley 17 to brake the rotation of the blade shaft 2, and is connected to an operating arm 45, which is rotated around the arm shaft 46 by the electric cylinder 44, by an operating wire 49. By pushing and rotating the electric cylinder 44, the operating arm 45 can be rotated from the cut-off position b of the mowing clutch 20 to the on position f, pulling the wire 43 and tensioning the tension pulley 18 and clutch arm 41 of the mowing clutch 20 against the mowing belt 19, thereby placing the mowing clutch 20 in a transmission-on position. Also, at this time, when the operating arm 45 is rotated from the brake position f to the brake release position e, the operating wire 49 is pulled, causing the brake arm 47 to rotate around the arm shaft 48, and the brake shoe 47s, which is fitted and pressed against the V-pulley groove of the blade pulley 17, is moved away from the outside in the radial direction, releasing the braking force and allowing smooth transmission of cutting power by the cutting belt 19 from the counter shaft 14 to the blade shaft 12.

[0021] Furthermore, the mowing clutch 20 and brake arm 47, which are operated via the electric cylinder 44, operating arm 45, operating wires 43, 49, clutch arm 41, brake arm 47, etc., are operated by shortening the electric cylinder 44 and rotating the operating arm 45 from clutch-on position a to clutch-off position b, so that the mowing clutch 20 moves away from the mowing belt 19 via the operating wires 43, 49 to a transmission-released position, and the brake shoe 47s of the brake arm 47 slides into contact with the V-groove portion of the blade pulley 17 of the blade shaft 2, putting the blade shaft 2 into a braking state.

[0022] In the abdominal section of the brush cutter body 5, the drive shaft 11 and the generator shaft 56 of the generator 25 hang down from the upper side of the engine base 15, and the upper end of the blade shaft 2 protrudes from the upper side of the mowing deck 3 at the bottom, and the counter shaft 14 is erected in a parallel arrangement with a front-to-rear distance on the center line L in the fore-to-aft direction. When the height of the mowing deck 3 is set to the intermediate position C, the upper counter pulley 13a of the counter shaft 14 is at approximately the same height as the lower drive pulley 12b at the lower end of the drive shaft 11, and the drive belt 10 stretched between the lower drive pulley 12b and the upper counter pulley 13a is configured to be stretched in a substantially horizontal manner from front to back. In this state, the drive belt 10, the mowing belt 19, and the generator belt 58 are stretched horizontally and parallel to each other. In addition, when the drive shaft 11, blade shaft 2, and counter shaft 14 are arranged side by side in a plan view, all of the shafts may be aligned with the center line L, but the drive shaft 11 does not necessarily have to be arranged in the center position of the left and right of the vehicle body 5, and may be offset to the left or right depending on the arrangement of the drive shaft 11 of the engine E, and when a pair of left and right blade shafts 11 are provided, the blade shafts 11 may be arranged to be distributed to the left and right of the center line L in a plan view.

[0023] The drive belt 10, which is a V-shaped belt stretched between the lower drive pulley 12b and the upper counter pulley 13a, has a tension pulley 60 provided near the outer periphery of the lower drive pulley 12b to constantly tension the drive belt 10 in a power transmission mode. The tension pulley 60 is rotatably provided at the tip of a tension arm 92 pivoted on a pivot shaft 91 of the upper engine base 15, and tensions the drive belt 10 by a spring 93. The tension pulley 60 presses against the back surface of the V-shaped drive belt 10 and is configured as a flat pulley (roll shape). The vertical height of the pulley 60 is formed slightly wider than the contact and rolling width of the drive belt 10. This causes the drive belt 10 to be slightly biased up and down when the mowing deck 3 is raised and lowered, and even if the engine base 15 swings left and right, the drive belt 10 is unlikely to come off or derail.

[0024] The engine base 15 has trapezoidal bracket arms 51 formed on the front and rear edges of its bottom to reinforce the support structure for the engine E and other components, and to facilitate setting a range of left and right rotation around a support member 16 on the center line L of the vehicle body 5. Support metal members 53 are provided at the center of the width of horizontal beams 52 extending laterally from left to right at the front and rear of the vehicle body 5, and the support members 16 provided at the lower center ends of the bracket arms 51 are fitted and supported between the front and rear support metal members 53, so that the engine base 15, which is normally positioned horizontally in the left-right direction, can rotate freely left and right over an appropriate angle θ range with respect to the vertical line Y of the vehicle body 5. An electric cylinder 54 provided between the vehicle body 5 and the engine base 15 extends and retracts to manually or automatically control the angle, so that the mounting position of the engine E on the inclined ground can always be maintained in the vertical position Y or at an angle within the allowable range of inclination of the engine E. Furthermore, a gas damper 103 is provided between the vehicle body 5 and the engine base 15, and pressure is constantly applied by the gas damper 103 in a direction that presses the electric cylinder 54, making it difficult for rattles to occur in the engine base 15 and other peripheral components. When the engine base 15 tilts, the gas damper also expands and contracts in accordance with the expansion and contraction of the electric cylinder 54, and the pressure is constantly applied, making it difficult for rattles or damage to occur in the components around the engine base 15.

[0025] An engine E is mounted on the front upper surface of the engine base 15, and at the rear thereof are mounted batteries 24a, 24b for starting the engine E and driving the motor M, a fuel tank 26, a generator 25, etc., which are arranged and attached so that the overall vehicle weight is distributed symmetrically on the left and right sides of the support member 16. The drive shaft 11 of the engine E protrudes vertically downward at the front of the engine base 15, and this drive shaft 11 is formed with pulleys with upper and lower V-shaped belt grooves, and a drive belt 10 is wound between the lower drive pulley 12b and the upper counter pulley 13a of the counter pulley 13 at the rear of the mowing deck 3, with a tension pulley 60 tensioned to constantly transmit rotation. An upper V-pulley 55 for driving the generator 25 is provided above the drive pulley 12, and a generator belt 58 is stretched between this and a generator pulley 57 attached to a generator shaft 56 of the generator 25 mounted at the rear of the upper V-pulley 55, and a tension pulley 59 is tensioned to transmit rotation at all times.

[0026] A rotating shaft 99 that rotates in conjunction with the generator shaft 56 is provided on the upper surface of the generator 25 in the vertical direction. A fan 97 is attached to the rotating shaft 99 and is covered from above by a fan cover 98. The outer diameter of the fan 97 is configured to be approximately the same as the outer diameter of the generator 25 in a plan view. The fan cover 98 has an elongated hole for intake on its upper surface and multiple elongated holes for exhaust on its side surface, and its bottom surface is open. As a result, when the generator shaft 56 is driven by the engine E and the rotating shaft 99 and fan 97 rotate, outside air is taken in through the intake holes on the top surface of the fan cover 98, and cooling air 100 is blown out from holes in the side surfaces of the fan cover 98 and an open portion at the bottom. Furthermore, because the fan cover 98 is configured to be larger than the generator, the cooling air 100 blown downward flows along the side surfaces of the generator 25. The cooling air 100 flows along the side of the generator 25, cooling the generator 25. Furthermore, the cooling air 100 flowing in front of the generator 25 can block heat flowing from the engine E toward the generator 25, improving the cooling performance of the generator 25. Additionally, the cooling air 100 blows down onto the batteries 24a, 24b located below the right side of the generator 25, thereby simultaneously cooling the batteries 24a, 24b. A cover 29 is provided above the fan cover 98, but approximately one-third to one-half of the front of the fan cover 98 is left uncovered by the cover 29 in a plan view. This allows the fan 97 to draw air from outside the cover 29, maintaining high cooling performance. The uncovered area of ​​the fan cover 98 may be at least partially covered by the cover 29, or may not be entirely covered. The holes on the side of the fan cover 98 may be provided on all sides, or may not be provided on some sides. Furthermore, the shape, size, number and arrangement of the holes on the top and side surfaces of the fan cover 98 are not particularly limited.

[0027] On the other hand, cooling air 100 generated from the side of the fan cover 98 in the outer circumferential direction of the fan 97 flows toward the front, side, and rear of the vehicle body 5, respectively. The cooling air 100 generated toward the front of the vehicle body 5 flows toward the top of the engine E. Here, the engine E has a cooling fan located at the top inside it that is driven by the crankshaft of the engine E and generates cooling air in a downward direction. The cooling air 100 generated toward the front of the vehicle body 5 flows around the intake port of the cooling fan provided in the engine E, preventing the intake of heated air by the muffler 88 and other components located in front of the engine E and improving the cooling efficiency of the engine E. In addition, the cooling air 100 flowing toward the right side of the vehicle body 5 flows toward the rectifier box 101. The rectifier box 101 generates a large amount of heat during the rectification process. However, a heat sink 106 is provided at the bottom, and by directing the cooling air 100 against the heat sink 106, the rectifier box 101 can be efficiently cooled. Furthermore, the cooling air 100 flowing toward the rear of the vehicle body 5 cools the fuel tank 26 located behind the generator 25, preventing a rise in fuel temperature and the resulting boiling and blowing out of the fuel. Furthermore, by sending the cooling air 100 into the cover 29, the air inside the cover 29 is agitated, thereby lowering the ambient temperature inside the entire cover 29. This makes it possible to prevent a rise in temperature not only in the batteries 24a, 24b, etc., which are covered by the cover 29, but also in the controller 23 and motor M, which are located toward the rear of the vehicle body 5 and are hardly reached directly by the cooling air 100.

[0028] Furthermore, ventilation holes 105 are provided on the top surface of the engine base 15, below the generator 25 and fuel tank 26. Cooling air 100 generated downward by the rotation of the fan 97 flows along the side of the generator 25 and blows down onto the top surface of the engine base 15, with a portion of the air passing through the ventilation holes 105 and exiting to the underside of the engine base 15. The drive belt 10 and generator belt 58 are stretched across the underside of the engine base 15. The durability of the belts is greatly affected by the ambient temperature around the belts, but the cooling air 100 can lower the ambient temperature around the drive belt 10 and generator belt 58, thereby improving the durability of the drive belt 10 and generator belt 58. [Explanation of symbols]

[0029] 1. Body 11 Drive shaft 15 engine base 25 Generator 29 Cover 56 Power generating shaft 97 Fans 99 Rotational Axis 100 Cooling air 104 Electrical equipment 105 Ventilation hole E-Engine

Claims

1. A cooling configuration for a work machine having an engine base (15) on a vehicle body (5), an engine (E) mounted on the upper surface of the engine base (15) at the front of the vehicle body (5), a generator (25) mounted rearward of the engine (E) and approximately in the center of the vehicle body (5) from front to rear, electrical equipment (104) mounted to the side or rear of the generator (25), and a cover (29) provided above the generator (25) and the electrical equipment (104), wherein the generator (25) has a rotating shaft (99) protruding upward from its upper surface and a generating shaft (56) protruding downward from its lower surface, the rotating shaft (99) and the generating shaft (56) being configured to rotate in conjunction with each other, a fan (97) attached to the rotating shaft (99), the generating shaft (56) rotating by being driven by the engine (E) to rotate the fan (97), and generating cooling air (100) below and in the outer circumferential direction of the fan (97).

2. 2. The cooling structure for a work machine according to claim 1, wherein at least a portion of the fan (97) is provided above the fan (97) that is not covered by the cover (29).

3. 3. A cooling configuration for a work machine according to claim 1 or 2, characterized in that the engine (E) has a drive shaft (11) that protrudes below the engine base (15), the drive shaft (11) and a generator shaft (56) that protrudes below the engine base from the underside of the generator (25) are configured to be capable of belt transmission between them, and a ventilation hole (105) is provided on the upper surface of the engine base (15) through which cooling air (100) generated downward by the fan (97) passes to the underside of the engine base (15).

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