Air conditioning system for work vehicles

Abstract

The objective is to provide a work vehicle that can heat the lower part of the cabin space using the temperature of the radiator coolant. [Solution] A work vehicle (1) is equipped with a cabin (10) that covers the driver's compartment and has an air conditioning unit (71) that air-conditions the inside of the cabin (10), wherein the air conditioning unit (71) uses the warmed cooling water after cooling the engine (E) as a heat source, and the air conditioning system of the work vehicle is equipped with an air conditioning system that supplies the cooling water to floor heater piping (943) located in the lower part of the cabin (10) interior space.

Description

Technical Field

[0001] The present invention relates to a heating device for a traveling vehicle having a cabin such as a tractor.

Background Art

[0002] In a traveling vehicle having a cabin, a work vehicle in which an air conditioner outlet is provided on the roof is known. (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The outlet of the air conditioner is above the living space, making it difficult to heat the driver's feet. An object of the present invention is to provide a work vehicle that can heat from the lower part of the cabin space by using the temperature of the cooling water of the radiator.

Means for Solving the Problems

[0005] The air conditioner of the work vehicle according to the present invention is a work vehicle (1) equipped with a cabin (10) that covers the control part of the work vehicle (1) and has an air conditioner unit (71) that air-conditions the inside of the cabin (10). In the air conditioner unit (71), the warmed cooling water after cooling the engine (E) is used as a heat source, and the cooling water is supplied to a floor heater pipe (943) arranged in the lower part of the space inside the cabin (10).

Effects of the Invention

[0006] According to the air conditioner of the work vehicle according to the present invention, the space inside the cabin (10) can be heated from the lower part.

Brief Description of the Drawings

[0007] [Figure 1] Figure 1 is a schematic diagram of a tractor equipped with an air conditioning structure according to an embodiment. [Figure 2] Figure 2 is a perspective view of the cabin shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of AA in Figure 1. [Figure 4] Figure 4 is a view from the arrow BB in Figure 3. [Figure 5] Figure 5 is a cross-sectional view of CC in Figure 3. [Figure 6] Figure 6 is a perspective view of the cabin frame shown in Figure 1. [Figure 7] Figure 7 is a perspective view of the frame shown in Figure 6, viewed from a different direction. [Figure 8] Figure 8 is a plan view of the air conditioning unit. [Figure 9] Figure 9 is a view from the DD arrow in Figure 8. [Figure 10] Figure 10 is a view from arrow EE in Figure 8. [Figure 11] Figure 11 is a view along the FF arrow in Figure 4, and is a bottom view of the air conditioner unit when it is installed in the air conditioner installation area. [Figure 12] Figure 12 is a schematic diagram showing the overall configuration of the air conditioning system installed in the tractor shown in Figure 1. [Figure 13] Figure 13 is a perspective view of the roof near the air conditioner installation area of ​​the tractor shown in Figure 1. [Figure 14] Figure 14 is an explanatory diagram showing the air conditioner with the top cover shown in Figure 13 removed. [Figure 15] Figure 15 is a view from the arrow GG in Figure 14. [Figure 16] Figure 16 is an explanatory diagram showing the case when the lower cover of the air conditioner shown in Figure 15 is removed. [Figure 17] Figure 17 is a perspective view of the tractor's floor, seen from above. [Figure 18]FIG. 18 is a perspective view showing the configuration of a heater pipe in another embodiment. [Figure 19] FIG. 19 is a left side view inside the bonnet. Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the air - conditioning structure of a work vehicle according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment. Also, the constituent elements in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same.

[0009] FIG. 1 is a schematic view of a tractor equipped with an air - conditioning structure according to an embodiment. In the following description, the front - rear direction, left - right direction, and up - down direction in the normal usage mode of the tractor 1 equipped with the air - conditioning device 70 (see FIG. 12) by the air - conditioning structure according to the present embodiment will be described as the front - rear direction, left - right direction, and up - down direction respectively at each part. The tractor 1 is a work vehicle that performs work in a field or the like, and has a front wheel 3 provided as a steering wheel and a rear wheel 4 provided as a driving wheel. Among these, the rear wheel 4 can transmit the rotational power generated by an engine (not shown) mounted in the bonnet 6 at the front of the machine body, after appropriately reducing the speed by a transmission 7. The rear wheel 4 generates a driving force by this rotational power. Also, this transmission 7 can transmit the rotational power generated by the engine E to the front wheel 3 as needed. In this case, a driving force is generated by the four wheels of the front wheel 3 and the rear wheel 4. That is, the transmission 7 can switch between two - wheel drive and four - wheel drive.

[0010] Also, at a position from above the rear wheel 4 to the front, a fender 33 is provided to cover the rear wheel 4 and suppress the scattering of soil lifted by the rear wheel 4. Further, at the rear part of the machine body of the tractor 1, a connecting device 8 to which a working machine such as a rotary (not shown) can be attached is disposed.

[0011] In the front region of the engine room within the bonnet 6, a base plate is provided on a pair of left and right longitudinally long vehicle frames, and on this base plate, a battery, a fuel cooler as a radiator, a capacitor 92, and a radiator 95 are arranged from the front.

[0012] The fuel cooler is for cooling fuel such as light oil to improve the combustion state of the engine E, and is disposed between the battery and the capacitor 92. The capacitor 92 cools the refrigerant of the air conditioner. The radiator 95 cools the cooling water of the engine E.

[0013] Figure 2 is a perspective view of the cab shown in Figure 1. The tractor 1 has a cab 10 into which a driver enters when operating the tractor 1. This cab 10 has a roof 12 at the upper part, and further has a plurality of pillars which constitute the cab 10 and are vertical pillars formed in the vertical direction of the tractor 1. That is, the cab 10 has, as a plurality of pillars, a front pillar 15, a center pillar 16, and a rear pillar 17, and one of each of these pillars is disposed on both sides in the left - right direction of the tractor 1.

[0014] Among these, the front pillar 15 is formed downward from near the front end of the roof 12 in the front - rear direction of the tractor 1, and the rear pillar 17 is formed downward from near the rear end of the roof 12. Also, the center pillar 16 is disposed at a position between the front pillar 15 and the rear pillar 17 in the front - rear direction, and is formed downward from the roof 12. The cab 10 can visually recognize the outside from the inside while forming a closed space inside by attaching transparent glass or the like to these pillars.

[0015] More specifically, a front windshield 26 is installed between the left and right front pillars 15, and a rear windshield 27 (see Figure 13) is installed between the left and right rear pillars 17. A rear side window 24 is installed between the center pillar 16 and the rear pillar 17. An opening / closing door 20 is positioned between the front pillar 15 and the center pillar 16.

[0016] The opening and closing door 20 is connected to the center pillar 16 by a hinge 21. This allows the opening and closing door 20 to rotate around the center pillar 16 as an axis, and this rotation allows it to open and close between the front pillar 15 and the center pillar 16. The opening and closing door 20 is provided with a side window 22, and the opening and closing door 20 can also see outside from the inside through the side window 22. In addition, a step 31 is provided below the opening and closing door 20 for stepping in and out of the cabin 10, and a side mirror 30 is attached to the front pillar 15 located in front of the opening and closing door 20 for viewing the rear of the tractor 1.

[0017] Furthermore, the tractor 1 is equipped with an air conditioning system 70 for regulating the temperature inside the cabin 10, and an air conditioning unit 71 (see Figure 3), which constitutes part of the air conditioning system 70, is housed in an air conditioning unit installation section 13 at the rear end of the roof 12. This air conditioning unit installation section 13 is located on the roof 12 above the cabin 10 and is provided so as to protrude from the rear of the cabin 10. Therefore, the air conditioning unit 71 is located at the upper rear of the cabin 10.

[0018] Figure 3 is a cross-sectional view AA of Figure 1. Figure 4 is a view along arrow BB of Figure 3. Figure 5 is a cross-sectional view CC of Figure 3. An air conditioning unit 71, which is located above the cabin 10 and protrudes to the rear of the cabin 10, is connected to an air conditioning duct 38 that is arranged forward from the air conditioning unit 71. In other words, the air conditioning duct 38 extends from the air conditioning unit 71 toward the interior of the cabin 10. This air conditioning duct 38 is arranged along the roof 12 toward the interior of the cabin 10 at two locations near both ends in the left-right direction, extending forward from the air conditioning unit 71. Multiple air outlets 39 are formed on the underside of the air conditioning duct 38, which blow the air flowing through the air conditioning duct 38 into the cabin 10.

[0019] Furthermore, within the cabin 10, an air conditioning control unit 35 for operating the air conditioning unit 71 is located in front of the driver's seat 105 where the tractor driver 100 sits. This air conditioning control unit 35 is located in front of the driver's seat 105 within the cabin 10, closer to the roof 12. In addition, the cabin 10 is equipped with comfort features for the driver 100 while driving, such as an audio unit 36.

[0020] Figure 6 is a perspective view of the cabin frame shown in Figure 1. Figure 7 is a perspective view of the frame shown in Figure 6 from another direction. The cabin 10 is constructed with a frame 40, and the frame 40 has a plurality of pillar frames 41 that form the skeleton of the pillars, which are vertical supports. Specifically, the frame 40 has, as pillar frames 41, a front pillar frame 42 that constitutes the front pillar 15, a center pillar frame 43 that constitutes the center pillar 16, and a rear pillar frame 44 that constitutes the rear pillar 17.

[0021] These front pillar frames 42, center pillar frame 43, and rear pillar frame 44 are arranged one on each side in the left-right direction, similar to the front pillar 15, center pillar 16, and rear pillar 17. Of these pillar frames 41, the front pillar frame 42 and rear pillar frame 44 are formed in a pipe-like shape with a hollow interior. The center pillar frame 43, when viewed in the direction of its extension, that is, when viewed in the vertical direction, is formed in a roughly U-shape.

[0022] Furthermore, the pillar frame 41 is connected near its upper end by another member. Specifically, a front cross member 46 extending in the left-right direction is provided between the upper ends of the front pillar frames 42 located on both the left and right sides, and the upper ends of both front pillar frames 42 are connected to this front cross member 46. Similarly, a rear cross member 47 extending in the left-right direction is provided between the upper ends of the rear pillar frames 44 located on both the left and right sides, and the upper ends of both rear pillar frames 44 are connected to the rear cross member 47. These front cross members 46 and rear cross members 47 are connected to the sides near the upper ends of the front pillar frames 42 and rear pillar frames 44, respectively.

[0023] Furthermore, a side member 48 extending in the front-rear direction is provided between the upper end of the front pillar frame 42 and the upper end of the rear pillar frame 44. The upper ends of both the front pillar frame 42 and the rear pillar frame 44 are connected to this side member 48. The upper end of the center pillar frame 43, located between the front pillar frame 42 and the rear pillar frame 44, is also connected to the side member 48, and this side member 48 is provided on both sides in the left-right direction.

[0024] Of these connections, the connection between the side member 48 and the front pillar frame 42 and rear pillar frame 44 is such that the side member 48 is connected to the side of the front pillar frame 42 and rear pillar frame 44 near their upper ends. Therefore, the upper ends of the front pillar frame 42 and rear pillar frame 44 are open. In contrast, the connection between the side member 48 and the center pillar frame 43 is such that the upper end of the center pillar frame 43 is connected to the side of the side member 48.

[0025] Furthermore, an air conditioning cover portion 50 is provided on the rear side of the rear cross member 47 in the longitudinal direction of the tractor 1, covering the lower part of the air conditioning unit 71. This air conditioning cover portion 50 is formed in a tray shape and is positioned behind the rear cross member 47 between the left and right rear pillar frames 44.

[0026] Furthermore, above the rear cross member 47, a bracket mounting frame 51 is positioned parallel to the rear cross member 47, extending in the left-right direction between the rear ends of the side members 48, similar to the rear cross member 47. Specifically, the rear cross member 47 is connected to a position slightly below the upper end of the rear pillar frame 44, while the bracket mounting frame 51 is connected to a position above the rear pillar frame 44.

[0027] A bracket 52 for mounting the air conditioner unit 71 is connected to this bracket mounting frame 51. Multiple brackets 52 extend from the bracket mounting frame 51 to the rear of the bracket mounting frame 51, and all of the brackets 52 are located above the air conditioner cover 50.

[0028] Furthermore, a fender frame 55 is provided on the frame 40 at the position where the fender 33 is mounted. Since this fender frame 55 is formed along the fender 33, it is provided from above to the front of the rear wheel 4 when the rear wheel 4 is mounted. This fender frame 55, like the pillar frame 41, is also formed from pipe-shaped members. That is, the fender frame 55 is formed from pipe-shaped members that are curved so that it extends in the longitudinal direction near the top of the rear wheel 4 and in the vertical direction near the front of the rear wheel 4, so that it is provided from above to the front of the rear wheel 4 when the rear wheel 4 is mounted.

[0029] Furthermore, the rear end of the fender frame 55, which is formed in this manner, is connected to the side of the rear pillar frame 44 near the lower end, in the portion that extends in the front-rear direction. The connection portion of the fender frame 55 on the rear pillar frame 44 is open, and the inside of the rear pillar frame 44 and the inside of the fender frame 55 are in communication with each other.

[0030] Furthermore, the lower end of the portion of the fender frame 55 that extends vertically is connected to the step frame 58, which is the portion to which the step 31 is attached. This step frame 58 is formed by connecting the upper end of a pipe-shaped member that extends vertically to the end of a pipe-shaped member that extends horizontally, and the step 31 is attached to this vertically extending portion. That is, the step 31 is fixed by inserting the mounting member 32 (see Figure 2), which is a pipe-shaped member of the step 31, into the vertically extending portion of the step frame 58.

[0031] The fender frame 55 is connected to the portion of the step frame 58 that extends in the left-right direction, and the connection point between the step frame 58 and the fender frame 55 is open. Therefore, the inside of the step frame 58 and the inside of the fender frame 55 are in communication with each other.

[0032] Figure 8 is a plan view of the air conditioning unit. Figure 9 is a view taken along the arrow DD in Figure 8. Figure 10 is a view taken along the arrow EE in Figure 8. The air conditioning unit 71 has a blower 72 that inhales and blows air, and along the airflow path of the blower 72, there is an evaporator 73 that performs heat exchange between this air and the refrigerant used in the air conditioning system 70, a heater core 74 that performs heat exchange between the air blown by the blower 72 and the coolant of the engine E, and a unit outlet 75 that blows the air, after heat exchange in the evaporator 73 and heater core 74, towards the air conditioning duct 38. The evaporator 73 has a built-in expansion valve, which enables heat exchange between the refrigerant vaporized by the expansion valve and the air blown by the blower 72. Furthermore, the evaporator 73 and the heater core 74 are positioned between the downstream side of the blower 72 and the unit outlet 75 in order to exchange heat with the air blown by the blower 72.

[0033] Furthermore, below the evaporator 73, there is a water collection section 77 that collects moisture in the air that has condensed due to the decrease in air temperature caused by heat exchange in the evaporator 73. The water collection section 77 is provided with a drainage section 78 that drains the water in the water collection section 77 to the outside of the air conditioning unit 71. This drainage section 78 is in the shape of a short pipe and is provided at two locations relative to the water collection section 77. The two drainage sections 78 protrude and open in opposite directions from each other. In addition, both of these drainage sections 78 protrude and open in a direction perpendicular to the direction in which the unit air outlet 75 opens.

[0034] In this configuration, the air conditioning unit 71 is configured such that the blower 72 is driven in response to operations on the air conditioning control unit 35, and the amount of air blown out from the unit outlet 75 can be changed.

[0035] Figure 11 is a view from the FF arrow in Figure 4, and is a bottom view of the air conditioner unit installed in the air conditioner installation section. The air conditioner unit 71 is installed in the air conditioner installation section 13 by being held by a bracket 52. Its orientation is such that the unit outlet 75 opens toward the front of the tractor 1, the water collection section 77 is located downwards, and the two drainage sections 78 provided in the water collection section 77 are attached to the bracket 52 in a direction that faces either left or right in the left-right direction of the tractor 1.

[0036] Two drainage sections 78 are located on the lower side of the air conditioning unit 71 and protrude to the left and right. Drainage hoses 86, which are drainage members, are connected to each of these drainage sections 78. One end of each drainage hose 86 is connected to a drainage section 78, and the other end is attached to a bracket 52. The air conditioning unit 71 is located near the left and right ends of the unit 71 in the tractor 1. In other words, the drainage hoses 86 are provided extending outward from the drainage sections 78 in the left and right directions of the tractor 1.

[0037] Furthermore, since the two drainage sections 78 are located at different distances from the end of the air conditioning unit 71, the length of the drainage hose 86 connected to each drainage section 78 also differs depending on which drainage section 78 the drainage hose 86 is connected to.

[0038] A T-shaped joint 88, having three connecting parts, is connected to the end of the drain hose 86 opposite to the end connected to the drain hose 78. Of the three connecting parts of this T-shaped joint 88, two are oriented in opposite directions on a straight line, and the remaining one is oriented perpendicular to the other two. The end of the drain hose 86 is connected to the connecting part of the T-shaped joint 88 that is oriented perpendicular to the other two. The other two connecting parts of the T-shaped joint 88 are oriented in the front-to-rear direction of the tractor 1 when connected to the end of the drain hose 86.

[0039] Of the three connection points of this T-shaped joint 88, drain hoses 80 that drain water discharged from the drain 78 to the outside of the tractor 1 are connected to the two connection points other than the end connected to the drain hose 86. The two connection points of the T-shaped joint 88 to which the drain hoses 80 are connected are oriented in the front-rear direction of the tractor 1, so the drain hoses 80 connected to these connection points are also positioned on the front and rear sides of the tractor 1, respectively, from the T-shaped joint 88. Thus, of the drain hoses 80 connected to the T-shaped joint 88, the drain hose 80 positioned on the front side is the front drain hose 81, and the drain hose 80 positioned on the rear side is the rear drain hose 82. In other words, the portion of the drain hose 80 located in front of the air conditioning unit 71 is the front drain hose 81, and the portion of the drain hose 80 located behind the air conditioning unit 71 is the rear drain hose 82.

[0040] Since the drain hose 86 and the drain hose 80 are connected via a T-joint 88, the drain hose 80 branches off from the drain hose 86 and is connected in two directions, front and rear, on the tractor 1. Furthermore, the drain hose 86 is connected to the drain hose 78 of the air conditioning unit 71, and the drain hose 80 is connected to the T-joint 88 which is connected to the drain hose 86. In other words, the drain hose 78 and the drain hose 80 are connected via the drain hose 86. Also, since the T-joint 88 and the drain hose 80 are connected to the drain hoses 86 located on both sides in the left-right direction of the tractor 1, the front drain hose 81 and the rear drain hose 82 are also located on both sides in the left-right direction of the tractor 1.

[0041] Figure 12 is a schematic diagram showing the overall configuration of the air conditioning system installed in the tractor shown in Figure 1. The air conditioning system 70 installed in the tractor 1 mainly consists of an air conditioning unit 71 and equipment connected to the air conditioning unit 71 via fluid pathways. The air conditioning unit 71, which constitutes the air conditioning system 70, is connected to a cooler pipe 90, which is a refrigerant passage through which the refrigerant used for heat exchange with air in the evaporator 73 flows, and a heater pipe 94, which is a heat transfer medium passage through which the cooling water of the engine E used for heat exchange with air in the heater core 74 flows.

[0042] Of these, the cooler piping 90 is connected to various components of the air conditioning system 70. Specifically, the cooler piping 90 is connected to, for example, a compressor 91 that compresses the refrigerant by being driven by power generated by the engine E, a condenser 92 which is a condenser that cools the refrigerant by exchanging heat between the refrigerant, whose temperature has risen due to compression, and the atmosphere, and liquefies the gaseous refrigerant, and a receiver dryer 93 which separates the liquid and gaseous parts of the refrigerant and removes moisture from the refrigerant. These components, such as the compressor 91, condenser 92, and receiver dryer 93, are located inside the bonnet 6 at the front of the aircraft.

[0043] The air conditioning unit 71 is connected to cooler piping 90 and supply heater piping 941 through which refrigerant and cooling water flow before heat exchange in the evaporator 73 and heater core 74, and to cooler piping 90 and return heater piping 942 through which refrigerant and cooling water flow after heat exchange. As a result, the air conditioning unit 71 is able to cool or heat the air flowing into the cabin 10 by performing heat exchange between the refrigerant flowing in through the cooler piping 90 and the cooling water flowing in through the supply heater piping 941 and the air flowing into the cabin 10 in the evaporator 73 and heater core 74.

[0044] Furthermore, the refrigerant circulation path is configured such that the cooler piping 90 before and after heat exchange is connected to the air conditioning unit 71, and the refrigerant after heat exchange flows back to the equipment side such as the compressor 91.

[0045] Here, the compressor 91 and other components are located inside the bonnet 6, but the engine E and other power source devices are also located inside the bonnet 6, and these power source devices become hot when in operation. In particular, the DPF (Diesel Particulate Filter) 96, which is a filter that reduces particulate matter contained in the exhaust gas discharged from the engine E, is prone to becoming hot. For this reason, the portion of the cooler piping 90 that passes near the DPF 96 is routed to avoid the heat effects of the DPF 96.

[0046] More specifically, the portion of the cooler piping 90 that passes near the DPF 96 is located behind the DPF bracket 97 that holds the DPF 96. In other words, the condenser 92 is located relatively far forward within the bonnet 6 so that it is easily exposed to the outside air in order to perform heat exchange between the refrigerant and the atmosphere. For this reason, the cooler piping 90 is routed from a forward position within the bonnet 6 to the rear of the cabin 10 where the air conditioning unit 71 is located, and also has a portion that is routed horizontally within the bonnet 6.

[0047] Thus, the DPF 96, which is installed in the bonnet 6, is positioned relatively towards the rear within the bonnet 6, similar to the cooler piping 90 installed in the bonnet 6. The DPF 96 is held in place by a DPF bracket 97, which has a holding portion that actually holds the DPF 96 and a mounting portion that attaches the DPF bracket 97 to the inside of the bonnet 6. The mounting portion is formed in a roughly rectangular plate shape, and most of it is located further rearward within the bonnet 6 than the DPF 96 held by the holding portion.

[0048] Of the cooler piping 90 installed inside the hood 6, the portion running in the left-right direction passes behind the DPF bracket 97. Therefore, the mounting portion of the DPF bracket 97 is interposed between the cooler piping 90 and the DPF 96, and the radiant heat from the high-temperature DPF 96 is blocked by the mounting portion of the DPF bracket 97. In other words, the DPF bracket 97 also plays a role in shielding the cooler piping 90 from the heat generated by the DPF 96.

[0049] Furthermore, since the drain hose 80 connected to the air conditioning unit 71 is branched in two directions, the drain hose outlet 85, which is an opening located at the end of the drain hose 80 and capable of draining water that has flowed through the drain hose 80, is located on both the front and rear sides of the position of the air conditioning unit 71 in the front-rear direction of the tractor 1. Specifically, of the two branched drain hoses 80, the rear drain hose 82 is arranged to be relatively short in length from the T-joint 88 towards the rear. For this reason, the drain hose outlet 85 of the rear drain hose 82 is located near the air conditioning unit 71, and is positioned further rear than the position of the air conditioning unit 71 in the front-rear direction of the tractor 1.

[0050] In contrast, the front drain hose 81 enters the rear pillar frame 44 through an opening at the upper end of the rear pillar frame 44, which is located in front of the air conditioning unit 71. In other words, the front drain hose 81 is connected to the end of the drain hose 86, which is located near where the end of the air conditioning unit 71 is located in the left-right direction of the tractor 1. Therefore, the portion of the front drain hose 81 connected to the T-joint 88 is also located near where the end of the air conditioning unit 71 is located in the left-right direction, and the front drain hose 81 is positioned forward from this location.

[0051] Therefore, the front drain hose 81 is routed from the position where it is connected to the T-joint 88 toward the part where the rear pillar frame 44 is installed, and this front drain hose 81 enters the rear pillar frame 44 through the opening at the upper end of the rear pillar frame 44. Furthermore, the front drain hose 81 enters the fender frame 55, which is connected to the rear pillar frame 44 on both sides, from near the lower end of the rear pillar frame 44.

[0052] Thus, the front drain hose 81, which is routed into the fender frame 55, has its end positioned inside the fender frame 55, or inside the step frame 58 which communicates with the inside of the fender frame 55, with the drain hose outlet 85 opening into the step frame 58. In other words, the front drain hose 81 is routed from inside the rear pillar frame 44 to inside the fender frame 55, with the drain hose outlet 85 opening into the step frame 58.

[0053] Figure 13 is a perspective view of the roof near the air conditioner installation area of ​​the tractor shown in Figure 1. Figure 14 is an explanatory diagram showing the air conditioner upper cover shown in Figure 13 removed. The roof 12 is formed by attaching a roof cover 60 to the side members 48 of the frame 40. An air conditioner installation area 13 is provided at the rear end of the roof 12, and the air conditioner installation area 13 is provided with an air conditioner upper cover 61, which is the upper cover of the air conditioner installation area 13, and an air conditioner lower cover 62. As a result, the air conditioner unit 71 is covered on the outside by both the air conditioner upper cover 61 and the air conditioner lower cover 62. Of these covers, the air conditioner upper cover 61 is detachably mounted to the roof 12 or to the frame 40, and the air conditioner unit 71 can be inspected by removing the air conditioner upper cover 61 from the roof 12.

[0054] Furthermore, the joint between the air conditioner upper cover 61, which is designed to be removable from the roof 12, and the roof cover 60, etc., is waterproofed using a gasket or the like.

[0055] Furthermore, the width of the roof 12, excluding the air conditioner installation area 13, increases from front to rear, with the widest point being directly in front of the air conditioner installation area 13. Within this wider section of the roof 12, located directly in front of the air conditioner installation area 13, is an outside air filter (not shown) that removes dust and dirt from the outside air when the air conditioner unit 71 is operating. When the air conditioner unit 71 draws in outside air, it uses this outside air filter to remove dust and dirt.

[0056] Figure 15 is a view from the direction of arrow GG in Figure 14. While the upper air conditioner cover 61 is removable, the lower air conditioner cover 62 is provided on the air conditioner installation section 13 so that it cannot be easily removed. The lower air conditioner cover 62 is inclined so that its lower surface is located downward from rear to front, and is inclined approximately 5° downward with respect to the direction of the road surface on which the tractor 1 travels. Below the air conditioner unit 71, drain hoses 86 and 80 are provided, but the portion of the drain hose 80 located below the air conditioner unit 71 and the drain hose 86 are covered by the lower air conditioner cover 62.

[0057] From the rear side of the lower air conditioner cover 62, the rear end of the rear drain hose 82 protrudes outwards. In other words, the rear drain hose 82 is positioned inside the lower air conditioner cover 62, and the drain hose outlet 85 is exposed to the outside of the lower air conditioner cover 62 from its rear end. In the rear drain hose 82, the portion exposed to the outside of the lower air conditioner cover 62 bends downwards near its rear end, causing the drain hose outlet 85 to bend downwards. The portion of the rear drain hose 82 exposed to the outside of the lower air conditioner cover 62 is located above the bottom surface of the lower air conditioner cover 62.

[0058] Figure 16 is an explanatory diagram showing the case when the lower air conditioner cover shown in Figure 15 is removed. The lower air conditioner cover 62 is inclined so that the bottom side is inclined so that the front side is inclined downwards, and the drain hose 80, which is located inside the lower air conditioner cover 62, is also inclined so that it is inclined downwards as it is directed towards the front of the tractor 1.

[0059] Specifically, the portion of the drain hose 80 covered by the air conditioner's lower cover 62 is connected to a T-shaped joint 88. The T-shaped joint 88 is inclined downwards from the connection point where the rear drain hose 82 is connected to the connection point where the front drain hose 81 is connected. As a result, the front drain hose 81 and the rear drain hose 82, which are connected to these connection points of the T-shaped joint 88, are inclined downwards from the rear to the front near the point where they are connected to the T-shaped joint 88. Consequently, the drain hose 80, which is installed inside the air conditioner's lower cover 62, has a downward slope towards the front, similar to the slope of the underside of the air conditioner's lower cover 62.

[0060] Furthermore, it is preferable that the inclination angle of the T-shaped joint 88, which is inclined downward from the rear to the front, is greater than or equal to the inclination angle of the lower surface of the air conditioner lower cover 62. For example, if the inclination angle of the lower surface of the air conditioner lower cover 62 is 5°, it is preferable that the inclination angle of the T-shaped joint 88 is inclined at about 10° with respect to the direction of the road surface on which the tractor 1 travels.

[0061] The air conditioning structure of the tractor 1 according to this embodiment has the configuration described above, and its operation will be explained below. When the tractor 1 is in operation, the driver 100 operates the steering wheel, various levers, and pedals inside the cabin 10 to control the movement of the tractor 1 and the operation of the implement connected to the coupling device 8. The tractor 1 is also equipped with an air conditioning system 70, which is operated by operating the air conditioning control unit 35 located inside the cabin 10.

[0062] When the temperature inside the cabin 10 is lowered by the air conditioning system 70 through the operation of the air conditioning control unit 35, first, the compressor 91 of the air conditioning system 70 is driven by the power generated by the engine E. As a result, the compressor 91 draws in and compresses the refrigerant in the cooler piping 90, and the temperature of the refrigerant rises due to this compression. This refrigerant, whose temperature has risen, flows from the compressor 91 to the condenser 92 through the cooler piping 90. The refrigerant that has flowed to the condenser 92 cools down by exchanging heat with the air passing through the condenser 92, etc., due to the operation of an electric fan (not shown). As a result, the refrigerant, whose pressure has increased due to compression by the compressor 91, cools down, and the gaseous refrigerant is liquefied in the condenser 92.

[0063] The liquefied refrigerant is further separated into gas and liquid in the receiver dryer 93, and after the water is removed, only the liquid refrigerant flows through the cooler piping 90 to the air conditioning unit 71. The refrigerant that flows into the air conditioning unit 71 flows to the evaporator 73 of the air conditioning unit 71. The refrigerant that flows to the evaporator 73 is vaporized by the expansion valve, and the temperature of the refrigerant decreases in the process.

[0064] On the other hand, when the air conditioning unit 70 is running, the blower 72 of the air conditioning unit 71 is driven and blows air toward the evaporator 73. The evaporator 73 exchanges heat between this air flowing on the outside of the evaporator 73 and the low-temperature refrigerant flowing on the inside, thereby lowering the temperature of the air. The air whose temperature has been lowered by the evaporator 73 is blown out from the unit outlet 75 and flows into the air conditioning duct 38, and is blown into the cabin 10 from the outlet 39 provided in the air conditioning duct 38. As a result, cooler air flows into the cabin 10, and the temperature inside the cabin 10 decreases. In addition, the refrigerant that has undergone heat exchange in the evaporator 73 flows out from the air conditioning unit 71 and flows again to the compressor 91 through the cooler piping 90.

[0065] In contrast, when the air conditioning unit 70 raises the temperature inside the cabin 10 by operating the air conditioning control unit 35, the engine coolant is supplied to the air conditioning unit 71 via the heater piping 941. In other words, since the engine coolant after warm-up is at a higher temperature than the outside temperature, this coolant is used as a heat transfer medium to raise the temperature inside the cabin 10.

[0066] Cooling water that flows into the air conditioning unit 71 via the supply heater piping 941 flows to the heater core 74 of the air conditioning unit 71. When the air conditioning system 70 is running, air blown from the blower 72 flows through the heater core 74, and the heater core 74 exchanges heat between this air flowing on the outside and the high-temperature cooling water flowing on the inside, raising the temperature of the air. The air whose temperature has risen in the heater core 74 is blown out from the unit outlet 75 and flows into the air conditioning duct 38, and is blown into the cabin 10 from the outlet 39 provided in the air conditioning duct 38. As a result, high-temperature air flows into the cabin 10, and the temperature inside the cabin 10 rises. The cooling water that has undergone heat exchange in the heater core 74 flows out of the air conditioning unit 71 and flows again towards the engine E through the return heater piping 942. When adjusting the temperature inside the cabin 10 by driving the air conditioning unit 70, the desired temperature is achieved by combining the process of lowering the temperature of the air blown into the cabin 10 with a refrigerant and raising the temperature with a refrigerant.

[0067] As shown in Figure 5, when the air conditioning duct 38 is equipped with an outlet 39, heating can only be done from above the driver's head, resulting in poor heating performance at the driver's feet during winter. Therefore, coolant is supplied to a floor heater pipe 943 located between the floor 101 and the floor mat 102, which is the lower part of the cabin space 10. Since the warmed coolant after cooling the engine E flows into the floor heater pipe 943, heating can be done from the lower part of the cabin space, warming the driver's feet.

[0068] Specifically, the coolant cooled by the radiator 95 lowers the temperature of the engine E, and the coolant, which has become hot due to the engine heat, is sent to the air conditioning unit 71 through the supply heater pipe 941 located in the front pillar frame 42. After heat exchange in the heater core 74, the coolant flows out of the air conditioning unit 71, flows again towards the engine E through the return heater pipe 942, and flows through the floor heater pipe 943 located in the lower part of the cabin space 10, and flows towards the engine E again, where it is cooled again by the radiator 95.

[0069] The floor heater piping 943 branches off from the return heater piping and is routed from the front pillar frame 42 under the floor mat 102, returning to the front pillar frame 42 before heading towards the engine E.

[0070] By utilizing the coolant flowing from the air conditioning unit 71 towards the engine E as a heat source, the air conditioning system 70 can also be used to warm the floor from the ground up using residual heat without reducing its performance.

[0071] Alternatively, in another embodiment, the supply heater pipe 941 may be branched before passing through the front pillar frame 42, and coolant may be flowed to the floor heater pipe 943.

[0072] By separating the cooling water supplied to the feed heater piping 941 from the cooling water supplied to the floor heater piping 943, the driver can be efficiently heated from both above their head and below their feet.

[0073] The end of the floor heater piping 943 is equipped with a valve 96 that allows or shuts off the supply of cooling water to the floor heater piping 943. When it is determined that heating from the floor is not necessary, such as when using air conditioning, the operator 100 can switch the valve 96 to stop the supply of cooling water.

[0074] If the coolant supply is stopped, the coolant heated by the engine will not flow through the floor heater pipe 943, so the feet will not be warmed, and the performance of the air conditioning will not be affected.

[0075] The air conditioning unit 70 uses a refrigerant and cooling water to adjust the temperature of the air blown into the cabin 10. When the evaporator 73 performs heat exchange between the air flowing outside the evaporator 73 and the refrigerant flowing inside the evaporator 73, and lowers the temperature of the air, the amount of saturated water vapor in the air decreases. As a result, the moisture in the air is more likely to condense into liquid, and the liquid moisture adheres to the evaporator 73 as water and gradually flows downward. A water collection section 77 is formed below the evaporator 73, so the water that flows downward from the evaporator 73 accumulates in the water collection section 77. The water accumulated in the water collection section 77 is drained from a drain section 78 provided in the water collection section 77 and flows out from the air conditioning unit 71.

[0076] Water drained from the drain section 78 flows into the drain section hose 86 connected to the drain section 78, and then flows from the drain section hose 86 to the drain hose 80 via the T-joint 88. This drain hose 80 is divided into a front drain hose 81 and a rear drain hose 82 by the T-joint 88, but the portion of the drain hose 80 covered by the air conditioner lower cover 62 has a downward slope towards the front. Therefore, when the tractor 1 is on a flat road or in a state where there is little difference in height between the contact surface of the front wheels 3 and the contact surface of the rear wheels 4, the water that flows from the drain section hose 86 to the drain hose 80 flows towards the front drain hose 81.

[0077] Since the front drain hose 81 enters the rear pillar frame 44 through an opening at the upper end of the rear pillar frame 44, which extends vertically, the front drain hose 81 is positioned downward from the opening at the upper end of the rear pillar frame 44. Therefore, when water flowing in the direction of the front drain hose 81 reaches the portion of the front drain hose 81 that is positioned inside the rear pillar frame 44, it flows downward along the front drain hose 81.

[0078] Water that has reached the position of the front drain hose 81 near the lower end of the rear pillar frame 44 flows further into the portion of the front drain hose 81 that extends into the fender frame 55. Since the drain hose outlet 85 of the front drain hose 81 located within the fender frame 55 opens into the step frame 58, the water that flows into this portion of the front drain hose 81 is drained out of the drain hose outlet 85 and flows into the step frame 58.

[0079] Water drained from the drain hose outlet 85 flows into the portion of the step frame 58 that extends in the left-right direction, and this water then flows into the portion of the step frame 58 that extends in the up-down direction. The mounting member 32 of the step 31 is inserted into this portion of the step frame 58, and the insides of both are in communication. Therefore, the water that flows into the step frame 58 flows into the mounting member 32 of the step 31 and flows out from below the mounting member 32. The water that flows into the front drain hose 81 is thus drained from below the step 31.

[0080] In this case, when the contact surface of the front wheels 3 is higher than the contact surface of the rear wheels 4, and the entire tractor 1 tilts downwards towards the rear, the drain hose 80 inside the air conditioner lower cover 62 also tilts downwards towards the rear, the water that flows from the drain hose 86 into the drain hose 80 flows towards the rear drain hose 82. The rear end of the rear drain hose 82 is exposed to the outside of the air conditioner lower cover 62 from the rear end of the air conditioner lower cover 62, and the drain hose outlet 85 is bent downwards, so the water that flows towards the rear drain hose 82 is drained from the drain hose outlet 85 of the rear drain hose 82.

[0081] Furthermore, regardless of the direction of the tractor 1's inclination, if a large amount of water flows from the drain hose 86 to the drain hose 80, the water will split and flow from the drain hose 86 into both the front drain hose 81 and the rear drain hose 82. As a result, the large amount of water flowing into the drain hose 80 will be drained from the drain outlets 85 of both the front drain hose 81 and the rear drain hose 82.

[0082] The air conditioning structure of the tractor 1 described above has drain hoses 80 arranged along the front-rear direction on both the left and right sides of the drain section 78 of the air conditioning unit 71 located at the rear upper part of the cabin 10, and the drain hose outlets 85 of the drain hoses 80 are positioned on both the front and rear sides of the position of the air conditioning unit 71 in the front-rear direction of the tractor 1. As a result, when the air conditioning system 70 is in operation, the water drained from the air conditioning unit 71 can be drained from at least one of the drain hose outlets 85 regardless of the tilt of the tractor 1. Furthermore, since multiple drain hose outlets 85 are formed, even if a large amount of water is drained from the air conditioning unit 71, it can be drained from multiple drain hose outlets 85. As a result, smooth drainage can be achieved.

[0083] Furthermore, the front drain hose 81 passes from the inside of the lower air conditioner cover 62 through the inside of the rear pillar frame 44, so the drain hose outlet 85 is located below the cabin 10 and is difficult to see from the outside. Similarly, the rear drain hose 82 is located inside the lower air conditioner cover 62, and the drain hose outlet 85 is exposed from the rear end of the lower air conditioner cover 62 to the outside, so the rear drain hose 82 is also difficult to see from the outside. For these reasons, both the front drain hose 81 and the rear drain hose 82 are difficult to see from the outside, improving the aesthetics. As a result, smooth drainage and improved aesthetics can be achieved simultaneously.

[0084] Furthermore, the drain hose 80, which is located inside the lower cover 62 of the air conditioner, is inclined downwards towards the front, allowing most of the water discharged from the air conditioner unit 71 to drain out of the drain hose outlet 85 of the front drain hose 81. This makes it less visible from the outside when the water discharged from the air conditioner unit 71 is drained from the drain hose 80 during operation of the air conditioning system 70. As a result, both reliable and smooth drainage and improved aesthetics can be achieved.

[0085] Furthermore, the drain hose 80 is connected to the drain hose 86, which is connected to the drain section 78 of the air conditioner unit 71, via a T-joint 88, and is branched in two directions. This ensures that a sufficient amount of water can be drained through the drain hose 80 per unit time. As a result, more reliable and smoother drainage can be achieved.

[0086] Furthermore, since the portion of the rear drain hose 82 that is exposed to the outside of the air conditioner lower cover 62 is positioned above the lower surface of the air conditioner lower cover 62, the lower surface of the air conditioner installation section 13 can be made flat. As a result, safety can be improved, and the aesthetic appearance can be improved more reliably.

[0087] Furthermore, by making the upper cover 61 of the air conditioner detachable, the air conditioner unit 71 can be easily inspected by removing the upper cover 61. As a result, maintainability can be improved. [Explanation of Symbols]

[0088] E-engine 1. Tractor (work vehicle) 6. Hood 10 cabins 12 Roof 13. Air conditioner installation area 42 Front pillar frame 70 Air conditioner 71 Air Conditioning Unit 94 Heater piping 941 Feed heater piping 942 Return heater piping 943 Floor heater piping 95 Radiator 96 Valves

Claims

1. It is equipped with a cabin that covers the control panel of the work vehicle, In a work vehicle equipped with an air conditioning unit for conditioned air inside the cabin, The aforementioned air conditioning unit utilizes the warmed coolant after the engine has been cooled as a heat source. An air conditioning system for a work vehicle, characterized by supplying the aforementioned cooling water to floor heater piping located in the lower part of the cabin space.

2. A heater supply piping for supplying the cooling water to the air conditioning unit, The air conditioning unit is equipped with a return heater pipe that supplies heater power to the engine, The air conditioning system for a work vehicle according to claim 1, wherein the cooling water is branched from the return heater pipe and supplied to the floor heater pipe.

3. The system includes a supply heater piping that supplies the cooling water to the air conditioning unit, The aforementioned cooling water The air conditioning system for a work vehicle according to claim 1, characterized in that it is supplied by branching to the aforementioned supply heater piping and the aforementioned floor heater piping.

4. The air conditioning system for a work vehicle according to claim 3, characterized in that a valve is provided in the floor heater piping for allowing or shutting off the supply of the cooling water.

Images