INSTALLATION STRUCTURE FOR RESERVOIR TANK

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2024-005450 filed on Jan. 17, 2024, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an installation structure for a reservoir tank.

BACKGROUND ART

In a water-cooled engine, a circulation flow passage is formed in which the cooling water from a water pump returns to the water pump via a water jacket in a cylinder and a radiator. There is known a motorcycle provided with this type of engine, in which a reservoir tank that temporarily stores the cooling water is provided below the engine (for example, see JP 2018-083606 A). In the engine described in JP 2018-083606 A, the reservoir tank is provided by effectively utilizing the lateral space of an oil pan, which includes relatively few components, ensuring sufficient tank capacity of the reservoir tank while preventing the vehicle from becoming larger.

SUMMARY

According to one advantageous aspect of the present invention, there is provided an installation structure for a reservoir tank, the installation structure including:

- a main frame that extends rearward from a head pipe;
- a down frame that extends downward from the head pipe;
- a bridge that connects the down frame and the main frame;
- a radiator disposed in front of the engine and configured to radiate heat from cooling water of an engine; and
- a reservoir tank configured to adjust a flow rate of cooling water in the radiator,
- wherein the reservoir tank is provided above the engine and rearward of the radiator so as to overlap a region surrounded by the main frame, the down frame, and the bridge in a side view.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a right side view of a straddle-type vehicle according to an embodiment.

FIG. 2 is a right side view of the periphery of an engine according to the present embodiment.

FIG. 3 is a front view of the periphery of the engine according to the present embodiment.

FIG. 4 is a side view of the periphery of a reservoir tank according to the present embodiment.

FIG. 5 is a top view of the periphery of the reservoir tank according to the present embodiment.

FIG. 6 is a front view of the periphery of the reservoir tank according to the present embodiment.

DETAILED DESCRIPTION OF EXEMPLIFIED EMBODIMENTS

In the lateral space of the oil pan, the reservoir tank needs to be provided taking into consideration not only the positional relationship with a drain bolt but also the minimum ground height, the bank angle, and the like, which has a significant impact on the vehicle body layout.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide an installation structure for a reservoir tank that can reduce the size of a vehicle while ensuring sufficient tank capacity and that can reduce an impact on the vehicle body layout.

In an installation structure for a reservoir tank according to one aspect of the present invention, a main frame extends rearward from a head pipe, a down frame extends downward from the head pipe, and the down frame and the main frame are connected by a bridge. The heat of the cooling water from an engine is radiated by a radiator in front of the engine, and the flow rate of the cooling water in the radiator is adjusted by the reservoir tank. The reservoir tank is provided using the dead space above the engine and rearward of the radiator so as to overlap a region surrounded by the main frame, the down frame, and the bridge in a side view. Sufficient tank capacity of the reservoir tank is ensured, and the reservoir tank is brought close to the radiator. Since the cooling system components of the engine are compactly arranged and do not interfere with the vehicle body frame, it is possible to prevent an increase in the size of the vehicle while reducing an impact on the vehicle body layout.

Embodiment

A straddle-type vehicle provided with a drainage structure for cooling water according to the present embodiment will be described below with reference to the accompanying drawings. FIG. 1 is a right side view of the straddle-type vehicle according to the present embodiment. In the following drawings, an arrow FR indicates a vehicle front side, an arrow RE indicates a vehicle rear side, an arrow L indicates a vehicle left side, and an arrow R indicates a vehicle right side.

As shown in FIG. 1, a straddle-type vehicle 1 is implemented by mounting various components such as an engine 30 and an electrical system on a vehicle body frame 10. A pair of main frames 12 extend rearward from a head pipe 11 (see FIG. 2) of the vehicle body frame 10, and the rear portions of the pair of main frames 12 form a pair of body frames 13 bent downward. A down frame 14 extends downward from the head pipe 11, and a pair of under frames 15 bent rearward are connected to the lower portion of the down frame 14. The rear end portions of the pair of under frames 15 are connected to the lower portions of the pair of body frames 13, and the vehicle body frame 10 is formed in a cradle shape.

A front fork 17 is supported on the head pipe 11 via a steering shaft (not shown) so as to be able to be steered. A handlebar 18 is provided on the upper portion of the front fork 17, and a front wheel 19 is rotatably supported on the lower portion of the front fork 17. A fuel tank 21 is placed over the upper portions of the pair of main frames 12, and the main frames 12 and the fuel tank 21 are covered by front side covers 22 from the lateral sides. A seat 23 is provided rearward of the fuel tank 21, and a seat frame (not shown) supporting the seat 23 from below is covered from the lateral sides by rear side covers 24.

A swing arm 25 is supported on the body frame 13 so as to be able to swing. The swing arm 25 extends rearward from the body frame 13, and a rear wheel 26 is rotatably supported at the rear end of the swing arm 25. The engine 30 is suspended inside the vehicle body frame 10 via a plurality of suspension brackets. A cylinder assembly in which a cylinder 32, a cylinder head 33, and a cylinder head cover 34 are stacked is provided on the upper portion of a crankcase 31 of the engine 30. A pair of left and right radiators 41 and 51 (only the right radiator 41 is shown in FIG. 1) are provided in front of the cylinder head 33.

In this type of straddle-type vehicle, the cooling water is circulated between the engine and the radiator, and the cooling water expands due to an increase in water temperature, which may damage the flow passage. Therefore, a reservoir tank is provided in the straddle-type vehicle to adjust the flow rate of the cooling water in the radiator. When the cooling water expands due to an increase in water temperature, the cooling water is released from the radiator to the reservoir tank. When the cooling water contracts due to a decrease in water temperature, the cooling water is returned from the reservoir tank to the radiator.

Although the reservoir tank is often provided at the vehicle rear side, the piping from the radiator on the vehicle front side to the reservoir tank is long, making assembly difficult.

Although the reservoir tank is often provided below the engine, it is difficult to provide the reservoir tank while taking into consideration the position of the drain bolt and the ability to drain oil from the drain hole while ensuring the minimum ground height, the bank angle, the seat height, and the like. There is a case in which the vehicle body layout such as the engine shape and the frame line needs to be reviewed as a whole. Therefore, in an installation structure for a reservoir tank 70 (see FIG. 2) according to the present embodiment, the reservoir tank 70 is provided above the engine 30 and rearward of the right radiator 41 using the dead space on the outer side of the vehicle body frame 10 in the vehicle width direction and on the inner side of the front side cover 22 in the vehicle width direction.

A cooling device for the engine will be described with reference to FIGS. 2 and 3. FIG. 2 is a right side view of the periphery of the engine according to the present embodiment. FIG. 3 is a front view of the periphery of the engine according to the present embodiment. In FIGS. 2 and 3, the exhaust pipe is omitted.

As shown in FIG. 2, the pair of left and right main frames 12 and the down frame 14 are connected to each other via a pair of left and right bridges 16 at the upper portion of the vehicle body frame 10. Below the bridge 16, the engine 30 is suspended from the vehicle body frame 10. The cylinder 32 is mounted on the crankcase 31, the cylinder head 33 is mounted on the cylinder 32, and the cylinder head cover 34 is mounted on the cylinder head 33. A clutch cover 35 that covers a clutch (not shown) is attached to the right side surface of the crankcase 31, and a water pump 36 that delivers the cooling water into the engine 30 is provided on the clutch cover 35.

As shown in FIGS. 2 and 3, the right radiator 41 and the left radiator 51 are provided in front of the cylinder head 33 with the down frame 14 at the center of the vehicle interposed therebetween. The right radiator 41 is formed larger than the left radiator 51. In the right radiator 41, a right inlet tank 43 is provided at the lower portion of a right radiator core 42, and a right outlet tank 44 is provided at the upper portion of the right radiator core 42. A radiator cap 46 is attached to a water supply port 45 of the right outlet tank 44. In the left radiator 51, a left inlet tank 53 is provided at the upper portion of a left radiator core 52, and a left outlet tank 54 is provided at the lower portion of the left radiator core 52.

The right inlet tank 43 is connected to the outlet of the cooling water from the engine 30 via an inlet hose 61. A thermostat (not shown) is provided at the outlet of the engine 30, and the inlet hose 61 is connected to the engine 30 via the thermostat. The right outlet tank 44 and the left inlet tank 53 are connected to each other via an inter-radiator hose 62. The left outlet tank 54 is connected to the water pump 36 via an outlet hose 63. A three-way pipe 64 is provided in the middle of the outlet hose 63, and a branch pipe of the three-way pipe 64 is connected to the upstream side of the thermostat via a bypass hose 65.

In the right radiator 41, the cooling water flows upward from the right inlet tank 43 toward the right outlet tank 44, and while the cooling water passes through the right radiator core 42, the heat of the cooling water is radiated into the air. The cooling water is sent from the right outlet tank 44 to the left inlet tank 53 through the inter-radiator hose 62. In the left radiator 51, the cooling water flows downward from the left inlet tank 53 toward the left outlet tank 54, and while the cooling water passes through the left radiator core 52, the heat of the cooling water is radiated into the air. The right radiator 41 and the left radiator 51 radiate the heat from the cooling water from the engine 30 in two stages in front of the engine 30.

The flow of the cooling water is controlled by the thermostat at the inlet of the inlet hose 61. When the temperature of the cooling water is lower than the predetermined temperature, the thermostat is closed, and the flow of the cooling water from the engine 30 toward the right radiator 41 through the inlet hose 61 is blocked at the thermostat. In this case, the cooling water is returned from the engine 30 to the water pump 36 through the bypass hose 65 upstream of the thermostat. When the temperature of the cooling water rises to the predetermined temperature or higher, the thermostat opens, and the cooling water flows from the engine 30 to the right radiator 41 and the left radiator 51 through the inlet hose 61, thereby effectively radiating the heat.

A cooling fan 55 is provided on the rear surface of the left radiator 51, and the reservoir tank 70 is provided rearward of the right radiator 41. The reservoir tank 70 is formed of a translucent resin material, and the colored cooling water that is stored in the reservoir tank 70 is visible from the outside. An F line 71 and an L line 72 are provided on the tank side surface of the reservoir tank 70 as inspection lines, and the F line 71 and the L line 72 are used to check whether the liquid amount of the cooling water is appropriate. A water supply pipe 73 extends obliquely upward and forward from the tank upper portion of the reservoir tank 70, and the cooling water can be added from the water supply pipe 73 when the liquid level of the cooling water falls below the L line 72.

The lower portion of the reservoir tank 70 is connected to the water supply port 45 of the right radiator 41 via a tank hose 74. When the cooling water expands during engine warming or the like, excess cooling water flows from the right radiator 41 into the tank hose 74 and is temporarily stored in the reservoir tank 70. When the engine 30 cools down and the cooling water contracts, the cooling water that is temporarily stored in the reservoir tank 70 is suctioned into the tank hose 74, and the cooling water is drawn back to the right radiator 41. In this way, the flow rate of the cooling water in the radiators 41 and 51 is adjusted by the reservoir tank 70. An overflow hose 75 is attached to the water supply pipe 73 of the reservoir tank 70 to guide the cooling water that overflows from the tank to below the engine 30.

The layout of the reservoir tank will be described with reference to FIGS. 4 to 6. FIG. 4 is a side view of the periphery of the reservoir tank according to the present embodiment. FIG. 5 is a top view of the periphery of the reservoir tank according to the present embodiment. FIG. 6 is a front view of the periphery of the reservoir tank according to the present embodiment. In FIG. 4, the front side cover is indicated by a two-dot chain line, in FIG. 5, the fuel tank is indicated by a two-dot chain line, and in FIG. 6, the left and right radiators are indicated by a two-dot chain line.

As shown in FIGS. 4 and 5, the reservoir tank 70 is provided on the right side of the vehicle body frame 10, and a fixing portion 77 in the vicinity of the water supply pipe 73 of the reservoir tank 70 and a fixing portion 78 on the tank rear side are fixed to the outer side surface of the main frame 12. The right radiator 41 is provided in front of the reservoir tank 70, and two upper and lower fixing portions 67 and 68 of the right radiator 41 are fixed to the down frame 14. A fuel tank 21 is provided above the reservoir tank 70, and the fuel tank 21 is supported from below by the pair of main frames 12. A right side portion 28 of the fuel tank 21 protrudes outward beyond the main frame 12 in the vehicle width direction, and the reservoir tank 70 overlaps the right side portion 28 of the fuel tank 21 in the top view. When the vehicle falls over, damage to the reservoir tank 70 is reduced by the fuel tank 21.

The reservoir tank 70 is located above the cylinder head cover 34 of the engine 30, below the upper surface of the main frame 12, and rearward of the right radiator 41. In the side view, the reservoir tank 70 overlaps a triangular region that is surrounded by the right main frame 12, the down frame 14, and the right bridge 16. In this way, the reservoir tank 70 is provided above the cylinder head cover 34 and rearward of the right radiator 41 in a space with relatively few components. The reservoir tank 70 is located close to the right radiator 41, and sufficient tank capacity is ensured in the reservoir tank 70.

As shown in FIG. 6, the right radiator 41 overlaps the fuel tank 21 in the front view, and the reservoir tank 70 is provided between the right radiator 41 and the fuel tank 21. The reservoir tank 70 acts as a windbreak for the fuel tank 21, and the exhaust air from the right radiator 41 to the fuel tank 21 is blocked by the reservoir tank 70, thereby preventing the thermal damage to the fuel tank 21. The heat shield plate for the fuel tank 21 is no longer necessary, so that the number of components is reduced, and the size of the vehicle is prevented from increasing. In the front view, the reservoir tank 70 is contained within the left-right width of the right radiator 41, and the right side of the reservoir tank 70 protrudes outward beyond the fuel tank 21 in the vehicle width direction.

In the front view, a part of the reservoir tank 70 bulges inward in the vehicle width direction, and a part of the reservoir tank 70 is inserted between the right main frame 12 and the right bridge 16. By expanding the reservoir tank 70 using the space between the main frame 12 and the bridge 16, the tank capacity is ensured without causing the reservoir tank 70 to protrude outward in the vehicle width direction, and an increase in the size of the vehicle is prevented. At the rear side of the right radiator 41, the main frame 12 and the bridge 16 are inclined forward and inward in the vehicle width direction. Therefore, even when the reservoir tank 70 is provided rearward of the right radiator 41, the reservoir tank 70 does not largely protrude outward in the vehicle width direction.

As shown in FIG. 4, the reservoir tank 70 and the right radiator 41 are covered with the right front side cover 22 from the lateral side. A decorative opening 27 is formed in the front side cover 22, and the reservoir tank 70 is partially exposed from this opening 27. In the side view, the opening 27 of the front side cover 22 exposes a portion above the F line 71 of the reservoir tank 70, and the front side cover 22 hides the cooling water below the F line 71 of the reservoir tank 70. Even though the cooling water is colored, the appearance of the vehicle is not marred, and the amount of the cooling water can be easily checked by looking into the reservoir tank 70 through the opening 27 of the front side cover 22.

As shown in FIGS. 4 and 6, the water supply pipe 73 extends forward from the upper portion of the reservoir tank 70 according to the inclination of the main frame 12, and a tank cap 79 is attached to the water supply port (not shown) at the distal end of the water supply pipe 73. The tank cap 79 (the water supply port) is exposed to the upper side of the right radiator 41. Even when the reservoir tank 70 is provided rearward of the right radiator 41, the tank cap 79 can be removed and the cooling water can be easily supplied to the reservoir tank 70. By extending the water supply pipe 73 upward from the reservoir tank 70, the reservoir tank 70 does not become large in the vehicle width direction, and an increase in the size of the vehicle is prevented.

The radiator cap 46 is provided on the upper portion of the right outlet tank 44 of the right radiator 41. In the front view, the tank cap 79 (the water supply port) of the reservoir tank 70 is located between the radiator cap 46 (the water supply port 45) of the right radiator 41 and the right main frame 12. The tank cap 79 of the reservoir tank 70 is provided using an empty space between the radiator cap 46 of the right radiator 41 and the main frame 12. When the radiator cap 46 and the tank cap 79 are brought close to each other, the water supply ports of the cooling water are collected at one place and the maintainability is improved.

As described above, according to the installation structure for the reservoir tank 70 in the present embodiment, the reservoir tank 70 is provided using the dead space above the engine 30 and rearward of the right radiator 41. Sufficient tank capacity of the reservoir tank 70 is ensured, and the reservoir tank 70 is brought close to the right radiator 41. Since the cooling system components of the engine 30 are compactly arranged and do not interfere with the vehicle body frame 10, it is possible to prevent an increase in the size of the vehicle while reducing an impact on the vehicle body layout.

Although the vehicle body frame is formed in the cradle shape in the present embodiment, the shape of the frame is not particularly limited as long as the vehicle body frame is formed in a shape in which the main frame and the down frame are connected by the bridge.

In the present embodiment, the left and right radiators are provided on the front side of the vehicle body. Alternatively, a single radiator may be provided on the front side of the vehicle body.

In the present embodiment, the reservoir tank is provided on the right side of the vehicle body. Alternatively, the reservoir tank may be provided on the left side of the vehicle body.

The drainage structure for cooling water according to the present embodiment is not limited to the straddle-type vehicle as described above, and may be used in other types of straddle-type vehicles. The straddle-type vehicle is not limited to a general vehicle in which a driver rides on a seat in a posture of straddling the seat, and includes a scooter-type vehicle in which the driver rides on the seat without straddling the seat.

As described above, the first aspect provides an installation structure for a reservoir tank, the installation structure including: a main frame (12) that extends rearward from a head pipe (11); a down frame (14) that extends downward from the head pipe; a bridge (16) that connects the down frame and the main frame; a radiator (a right radiator 41) disposed in front of the engine (30) and configured to radiate heat from cooling water of an engine (30); and a reservoir tank (70) configured to adjust a flow rate of cooling water in the radiator, in which the reservoir tank is provided above the engine and rearward of the radiator so as to overlap a region surrounded by the main frame, the down frame, and the bridge in a side view. According to this configuration, the reservoir tank is provided using the dead space above the engine and rearward of the radiator. Sufficient tank capacity of the reservoir tank is ensured, and the reservoir tank is brought close to the radiator. Since the cooling system components of the engine are compactly arranged and do not interfere with the vehicle body frame, it is possible to prevent an increase in the size of the vehicle while reducing an impact on the vehicle body layout.

A second aspect is directed to the first aspect, in which the radiator overlaps a fuel tank (21) in a front view, and the reservoir tank is provided between the radiator and the fuel tank. According to this configuration, the exhaust air from the radiator to the fuel tank is blocked by the reservoir tank, thereby preventing the thermal damage to the fuel tank. The heat shield plate is no longer necessary, so that the number of components can be reduced, and the size of the vehicle can be prevented from increasing.

A third aspect is directed to the first aspect or the second aspect, in which a part of the reservoir tank is inserted between the main frame and the bridge in the front view. According to this configuration, the tank capacity is ensured without causing the reservoir tank to protrude outward in the vehicle width direction, and an increase in the size of the vehicle is prevented.

A fourth aspect is directed to any one of the first to third aspects, the installation structure further including a side cover (a front side cover 22) covering the reservoir tank from a lateral side, in which an opening (27) for partially exposing the reservoir tank is formed in the side cover, and an inspection line (an F line 71) for cooling water is formed on a tank side surface of the reservoir tank, and in which an opening of the side cover exposes a portion of the reservoir tank above the inspection line in the side view. According to this configuration, since the cooling water below the inspection line is hidden by the side cover, even though the cooling water is colored, the appearance of the vehicle is not marred. The amount of the cooling water can be easily checked by looking into the reservoir tank through the opening of the side cover.

A fifth aspect is directed to any one of the first to fourth aspects, in which a water supply pipe (73) extends obliquely upward and forward from a tank upper portion of the reservoir tank, and a water supply port at a distal end of the water supply pipe is exposed to an upper side of the radiator in the front view. According to this configuration, even when the reservoir tank is provided rearward of the radiator, the cooling water can be easily supplied to the reservoir tank.

The reservoir tank does not become large in the vehicle width direction, and an increase in the size of the vehicle is prevented.

A sixth aspect is directed to the fifth aspect, in which a water supply port (45) is formed in an upper portion of the radiator, and a water supply port of the water supply pipe of the reservoir tank is located between the water supply port of the radiator and the main frame in the front view. According to this configuration, the water supply port of the reservoir tank is formed using an empty space between the water supply port of the radiator and the main frame, so that the increase in the size of the vehicle is prevented. By bringing the water supply ports of the radiator and the reservoir tank close to each other, the maintainability is improved.

Although the present embodiment is described, a part or all of the embodiment and a modification may be combined as another embodiment.

The technique according to the present invention is not limited to the above-described embodiment, and may be variously changed, replaced, or modified without departing from the gist of the technical concept. Further, the present invention may be implemented by other methods as long as the technical concept can be implemented by the methods through advance of the technique or other derivative techniques. Therefore, the claims cover all embodiments that may fall within the scope of the technical concept.

INSTALLATION STRUCTURE FOR RESERVOIR TANK

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Priority Claims (1)