JP2024088366A - Work vehicles - Google Patents

Abstract

[Problem] To provide an electric work vehicle with good weight balance. [Solution] In a work vehicle equipped with a work implement 4 mounted on a traveling body 1, electric motors 30, 40 are provided to drive the drive wheels 3 of the traveling body 1 or the work implement 4, a battery 50 is provided to feed power to the electric motors 30, 40 and store electricity, and a mounting frame 57 for mounting a replacement battery 50A is provided in the front of the traveling body 1 in a manner that allows it to be raised and lowered. [Selected Figure] Figure 13

Description

The present invention relates to a work vehicle such as a lawnmower that is driven through parks and other areas to mow the grass there.

A work vehicle equipped with a battery and an electric motor, which is powered by a stored battery and operates the electric motor to drive a work machine or drive wheels, is known in which multiple battery packs are slidably inserted near the axle between the left and right rear wheels (Patent Document 1).

Patent No. 6727861

According to Patent Document 1, in an electric work vehicle in which a work device is located between the front and rear wheels, the battery mounting section is located near the rear wheel axle, a configuration that takes into consideration the space required for installation. However, because the battery is a heavy component, the above configuration poses the problem of the weight balance being biased towards the rear wheels.

The present invention aims to provide an electric work vehicle that can achieve good weight balance.

In order to solve the above problem, the invention described in claim 1 is a work vehicle equipped with a work machine 4 mounted on a traveling body 1, which is provided with electric motors 30, 40 for driving the drive wheels 3 of the traveling body 1 or the work machine 4, a battery 50 for supplying power to the electric motors 30, 40 and storing the power, and a mounting frame 57 for mounting a replacement battery 50A is provided at the front of the traveling body 1 in a manner that allows it to be raised and lowered.

According to the invention described in claim 1, work in the field can be carried out efficiently without being interrupted during charging. In addition, by placing the battery, which is a heavy object, at the front of the traveling body 1, the front-rear weight balance can be adjusted without attaching weights.

FIG. 1 is a left side view of a work vehicle according to an embodiment of the present invention. FIG. 2 is a left side view of the work vehicle with the bonnet cover in an open position. 1 is a perspective view of a main portion of a work vehicle with a part cut away; FIG. FIG. 2 is a plan view of the rear wheels and essential parts of the working machine. FIG. 4 is a left side view of the rear wheel and essential parts of the work machine. FIG. 2 is a left side view of the electric motor for the rear wheels and the electric motor for the work machine. FIG. FIG. FIG. 2 is a perspective view of a battery and a battery bracket. FIG. FIG. 2 is a front view of the front wheel, the battery, and the battery bracket. 1 is a side view of a battery lifting device for a work vehicle according to an embodiment of the present invention. FIG. 2 is a plan view of the main parts of the work vehicle with a portion thereof omitted. FIG. FIG. FIG. FIG. FIG. FIG.

As shown in FIG. 1, a work vehicle such as a riding lawnmower has a running body 1, a pair of left and right front wheels 2 at the front of the running body 1, a pair of left and right rear wheels 3 at the rear of the running body 1, and a working machine 4 for cutting grass and the like between the front wheels 2 and rear wheels 3 on the underside of the running body 1. In addition, a bonnet 5 for storing a battery described below is provided at the front of the upper part of the running body 1, a driver's seat 60 for the driver is provided behind the bonnet 5, a safety frame (ROPS) 8 for protecting the driver is provided behind the driver's seat 60, and a grass collection container 7 for storing grass and the like cut by the working machine 4 is provided below the safety frame 8.

As shown in Figures 2 to 4, a battery 50 is provided inside the bonnet 5 to store electricity to be supplied to the electric motor 30 that drives the rear wheels 3. The bonnet 5 is supported by a support shaft (not shown) that is provided at the upper rear part and extends in the left-right direction. This allows the front part of the bonnet 5 to rotate upward.

Electrical components 61 are provided below the cockpit 60. This allows the space below the cockpit 60 to be used effectively.

The safety frame 8 is formed from a left support section 8L that extends vertically, a right support section 8R that extends vertically, and an inverted U-shaped connecting section 8A that connects the upper parts of the left support section 8L and the right support section 8R.

As shown in Figures 4 to 7, an electric motor 30, such as a synchronous motor or induction motor, operated with a three-phase AC voltage waveform that drives the rear wheels 3, is provided below the electrical components 61. The output shaft 30A, which extends in the left-right direction of the electric motor 30, is connected to the upper part of a gear box 31 that reduces the speed of the output rotation transmitted from the output shaft 30A to increase the output torque or reverse the direction of rotation. The electric motor 30 is provided in a position offset to the left of the center in the left-right direction.

The output rotation that has been accelerated or decelerated by the gear box 31 is transmitted to the drive shaft 33 extending in the left-right direction via a differential gear 32 that is provided at the bottom of the gear box 31 and is composed of a differential gear or the like. The output rotation transmitted to the drive shaft 33 is transmitted to the rear wheels 3 that are supported at both ends of the drive shaft 33.

Below the motor 30, there is provided a motor 40 such as a synchronous motor or induction motor operated with a three-phase AC voltage waveform that drives the work machine 4. The output shaft 40A formed extending in the front-rear direction of the motor 40 is connected to the rear of a universal joint 41 provided extending in the front-rear direction. The output shaft 40A is provided above the drive shaft 33 and perpendicular to the drive shaft 33. This allows the space formed below the motor 30 to be effectively utilized. In addition, the transmission path between the motor 40 and the work machine 4 can be shortened, so that the output rotation of the motor 40 can be efficiently transmitted to the work machine 4. The motor 40 is provided at a position offset to the left of the center in the left-right direction.

The front part of the universal joint 41 is connected to a gear box 42 that reduces the speed of the output rotation transmitted from the universal joint 41 to increase the output torque. The output rotation transmitted to the gear box 42 is transmitted to a left cutting blade (not shown) provided in the left discharge passage 45L of the work machine 4 via an output shaft formed by extending in the vertical direction of the gear box 42.

A connecting member 43 extending in the left-right direction is connected to the gearbox 42, and the right part of the connecting member 43 is connected to the gearbox 44. The output rotation transmitted to the gearbox 44 is transmitted to a right cutting blade (not shown) provided in the right discharge passage 45R of the work machine 4 via an output shaft formed by extending in the up-down direction of the gearbox 44. The output rotation speeds of the output shafts of the gearbox 42 and the gearbox 44 are the same, but the rotation directions are opposite; that is, in a plan view, the output shaft of the gearbox 42 rotates clockwise, and the output shaft of the gearbox 44 rotates counterclockwise.

The discharge outlets of the left discharge passage 45L and the right discharge passage 45R are connected to the inlet of the chute 46, which transports the cut grass and other materials to the grass collection container 7. The discharge outlet of the chute 46 is connected to the inlet of the grass collection container 7.

In plan view, the front of the chute 46 is provided to the right of the universal joint 41, the rear of the chute 46 is provided to the right of the gear box 31, and in rear view, the chute 46 and grass collection container 7 are provided between the gear box 31 and the right rear wheel 3. This allows a large chute 46 to be provided in the space formed to the right of the universal joint 41 and the gear box 31, and grass and other materials cut by the work machine 4 can be efficiently transported to the grass collection container 7.

When viewed from the side, the upper wall of the chute 46 is formed with an upward incline toward the rear, and the rear of the chute 46 extends downward below the electrical components 61. This makes the rear of the chute 46 larger, preventing grass and other debris from clogging the inside of the chute 46.

As shown in Figures 8 and 9, the vehicle body 1 is formed of a vehicle frame 10 that supports the front wheels 2 and the rear wheels 3, and a steering post 11 that supports the steering shaft 63.

The vehicle body frame 10 is formed with a left front-rear frame 10L and a right front-rear frame 10R that extend in the fore-aft direction, and the lower part of the steering post 11 is formed with a left connecting part 11L and a right connecting part 11R that extend forward.

The left connecting part 11L is fixed to the left front and rear frame 10L by a fastening means such as a bolt, and the right connecting part 11R is fixed to the right front and rear frame 10R by a fastening means such as a bolt, and they are integrated to form the traveling vehicle body 1.

A left support member 12L is provided at the front of the left front-rear frame 10L, and the connecting portion of the left support member 12L is formed with an upward incline to the left. A right support member 12R is provided at the front of the right front-rear frame 10R, and the connecting portion of the right support member 12R is formed with an upward incline to the right. The left support member 12L and the right support member 12R are made of channel steel.

A left support member 13L is provided in front of the left connecting part 11L, and the connecting part of the left support member 13L is formed with an upward incline to the left. A right support member 13R is provided in front of the right connecting part 11R, and the connecting part of the right support member 12R is formed with an upward incline to the right. The left support member 13L and the right support member 13R are made of channel steel.

The lower part of the steering post 11 is formed with protrusions 14 that protrude forward at a predetermined distance in the left-right direction, and a buffer member 15 made of rubber or the like is provided at the tip of the protrusion 14.

As shown in FIG. 10, the lower part of the battery 50 provided inside the bonnet section 5 is fitted inside the inner circumference of the battery bracket 52. The battery 50 is formed by connecting multiple high-energy-density lithium-ion batteries in series and parallel. This allows the space formed in the bonnet section 5 to be used effectively. In addition, because the lithium-ion battery has a high energy density, the work vehicle can travel long distances on a single full charge.

As shown in FIG. 11, the battery bracket 52 is formed of a left front-rear frame 52L and a right front-rear frame 52R extending in the front-rear direction, a front left-right frame 52A connecting the front parts of the left front-rear frame 52L and the right front-rear frame 52R, and a rear left-right frame 52B connecting the rear parts of the left front-rear frame 52L and the right front-rear frame 52R. The left front-rear frame 52L and the right front-rear frame 52R are formed from angle steel, and the front left-right frame 52A and the rear left-right frame 52B are formed from channel steel.

The connecting portion of the left front-rear frame 52L is inclined upward to the left, and the connecting portion of the right front-rear frame 52R is inclined upward to the left. In rear view, the connecting portion of the left support member 13L, the connecting portion of the left support member 12L, and the connecting portion of the left front-rear frame 52L are inclined upward to the left at the same inclination angle, and the connecting portion of the right support member 13R, the connecting portion of the right support member 12R, and the connecting portion of the right front-rear frame 52R are inclined upward to the right at the same inclination angle.

A circular left vibration isolator 53L is provided at a predetermined distance in the front-to-rear direction on the underside of the connecting part of the left front-to-rear frame 52L, and a circular right vibration isolator 53R is provided at a predetermined distance in the front-to-rear direction on the underside of the connecting part of the right front-to-rear frame 52R.

The left front and rear frame 52L is connected to the left support member 12L of the left front and rear frame 10L and the left support member 13L of the left connecting part 11L via the left vibration isolator 53L, and the right front and rear frame 52R is connected to the right support member 12R of the right front and rear frame 10R and the right support member 13R of the right connecting part 11R via the right vibration isolator 53R. This prevents vibrations of the traveling vehicle body 10 that occur when the work vehicle is traveling from being transmitted to the battery 50, preventing damage to the battery 50, etc.

As shown in FIG. 12, the connecting portion of the left front and rear frame 52L is provided perpendicular to the left imaginary line 55L that connects the center of the left vibration isolator 53L and the center of the left front wheel 2L on the left side. In addition, the connecting portion of the right front and rear frame 52R is provided perpendicular to the right imaginary line 55R that connects the center of the right vibration isolator 53R and the center of the right front wheel 2R on the right side. This makes it possible to suppress large vibrations caused by unevenness in the driving surface via the front wheels 2 and rear wheels 3, and to prevent damage to the battery 50, etc.

Next, the support structure for the replacement battery 50A will be described. In FIG. 13, a lifting link mechanism 56 is provided at the front of the body frame 10 to support the replacement battery 50A. That is, the lifting link mechanism 56 has a mounting frame 57 at the front, and the mounting frame 57 is connected to the left and right lower links 56a, 56a protruding forward and the top link 56b so that the mounting frame 57 can be raised and lowered. The lower links 56a, 56a are linked together and rotated around the fulcrum on the body frame 10 side by the extension and contraction of the cylinder mechanism 58, thereby allowing the mounting frame 57 to be raised and lowered. The operation of the cylinder mechanism 58, which links the lifting link mechanism 56, is controlled based on the operation of a lifting switch or a lifting lever (not shown).

The support structure for the replacement battery 50A on the mounting frame 57 of the lifting link mechanism 56 is, for example, a battery bracket 52A having a structure similar to the battery bracket 52 (FIG. 11). The traveling vehicle body 1 is brought close to the replacement battery 50A that has been fully charged in advance, and the lifting link mechanism 56 is lowered to mount the replacement battery 50A on the battery bracket 52A of the mounting frame 57. The lifting link mechanism 56 is raised and held at an appropriate height, and work is started while traveling the traveling vehicle body 1. When it is time to replace the battery 50 attached to the main body after a predetermined time has elapsed since the start of work, the traveling vehicle body 1 is stopped, the on-board battery 50 is replaced with the replacement battery 50A on the mounting frame 57 side, and work is continued. Therefore, work in the field can be performed efficiently without being interrupted during charging. In addition, by placing the heavy battery at the front of the traveling vehicle body 1, the front-rear weight balance can be adjusted without attaching a weight.

As shown in Figures 2, 3, and 14, a steering wheel 62 is provided in front of the cockpit 60, and the steering wheel 62 is supported on the upper part of a steering shaft 63 that extends in the vertical direction.

A cleaner lever 65 is provided on the left fender 64L on the left side of the operator's seat 60 to transport grass clippings remaining inside the chute 46 to the grass collection container 7 at the rear, while an operating lever 66 is provided on the right fender 64R of the operator's seat 60 to raise and lower the work machine 4. A brake pedal 68 (described below) is provided on the left front part of the floor 67 on which the operator places his or her feet when operating the vehicle, and a forward accelerator pedal 70 and a reverse accelerator pedal 71 are provided side by side on the right front part.

The electrical components 61 installed in the space between the chute 46 of the work machine 4 and the cockpit 60 are composed of an inverter device 80 that converts the DC voltage supplied from the battery 50 into AC voltage and generates a three-phase AC voltage waveform to operate the electric motor 30, a battery monitoring device 81 that monitors the temperature, charging state, voltage protection, and short-circuit state of each cell of the battery 50, an auxiliary battery 82 such as a lead storage battery that stores electricity to be supplied to the meter panel that displays the driving speed and the like installed in front of the cockpit 60, and a converter device 83 that converts the DC voltage supplied from the battery 50 into DC voltage to be supplied to a sensor that detects the operating position of the cleaner lever 65, etc.

The inverter device 80 is composed of an inverter device 84 that operates the electric motor 30 and an inverter device 85 that operates the electric motor 40. In addition, when regenerative braking is activated, that is, when the forward accelerator pedal 75 or the reverse accelerator pedal 76 is released and the output shaft 30A rotates due to the inertial force of the traveling vehicle body 1 and the electric motor 30 operates as a generator, the inverter device 84 also functions as a charging device that charges the battery 50 with the power supplied from the electric motor 30 to the inverter device 80.

Similarly, when the PTO is switched OFF, the inertial force of the left and right cutting blades rotates the output shaft 40A and the electric motor 40 operates as a generator, but in this case, the regenerative brake is also activated to stop the work machine 4, and the inverter device 85 functions as a charging device that charges the battery 50 with the power supplied from the electric motor 40 to the inverter device 80.

In plan view, an inverter device 80 is provided at the front below the driver's seat 60, and a battery monitoring device 81 is provided behind the inverter device 80. An auxiliary battery 82 is provided to the left of the inverter device 80, and a converter device 83 is provided to the left of the battery monitoring device 81 and behind the auxiliary battery 82. This allows the space formed below the driver's seat 60 to be effectively utilized. Also, by providing the heavy battery monitoring device 81 at the rear, the difference in weight applied to the front and rear of the traveling vehicle body 10 can be reduced, improving traveling stability.

The battery monitoring device 81 is equipped with a means for monitoring the remaining charge, and when the remaining charge falls below a predetermined level, it first stops the drive command to the work machine electric motor 40. This results in output from only the travel electric motor 30, and although work is interrupted, movement for battery charging work is not hindered.

In FIG. 8, a left upper/lower frame 20L is provided at the rear of the left front/rear frame 10L, and a right upper/lower frame 20R is provided at the rear of the right front/rear frame 10R, and the upper parts of the left upper/lower frame 20L and right upper/lower frame 20R are connected to a left/right frame 21 that extends in the left/right direction.

A left connecting part 22L is provided on the left part of the left-right frame 21 to which the lower part of the left support part 8L of the safety frame 8 is connected, and a right connecting part 22R is provided on the right part of the left-right frame 21 to which the lower part of the right support part 8R of the safety frame 8 is connected.

The frame structure frame, which is composed of the left upper and lower frames 20L, the right upper and lower frames 20R, and the left and right frames 21, constitutes the support frame 25 for the grass collection container 7. The grass collection container 7 is connected to this support frame 25. That is, the grass collection container 7 is connected to the fulcrum pin 7P at the front upper part of the grass collection container 7 so that it can rotate up and down around the fulcrum pin 7P. As a result, as shown in FIG. 1, the grass collection container 7 can be changed to a working position in which the front part contacts a shielding plate part (not shown) surrounded by the support frame 25, and a grass clippings discharge position in which the rear part of the grass collection container 7 is flipped up. The right side of the grass collection container 7 is equipped with a known rotating handle 7L, and by grabbing the grip part at the top end and tilting it forward, it can be changed to the grass clippings discharge position, which is a non-working position. In this case, the grass stored in the container is discharged to the ground from the open part at the front.

Next, the dolly 90 on which the replacement battery 50B is placed will be described with reference to Figures 16 and 17. The dolly 90, which is equipped with casters 91, 91, is configured with a battery bracket (not shown) similar to the battery bracket 52, and is configured to be able to place a charged replacement battery 50B. A connecting means (not shown) is provided between the dolly 90 and the body frame 10 of the traveling vehicle body 1, and is configured so that the dollies 90 can be connected in a close proximity to each other without causing any deviation in their relative positional relationship.

Therefore, the bonnet 5 is opened in advance, the battery 50 mounted on the vehicle frame 10 side of the traveling vehicle body 1 is removed, and the replacement battery 50B of the cart 90 connected closely to the traveling vehicle body 1 is slid toward the traveling vehicle body 1 side, so that it can reach the specified storage position along the rail member 92 installed on the traveling vehicle body 1 side. This makes it easy to replace the battery on the cart 90 located at the front.

As shown in Figures 18 to 20, a brake pedal 68 is provided on the floor 67, to which the front end of a brake rod 96 is connected. The rear end of the brake rod 96 is connected to a brake 97 provided on the rear wheel 3 so as to be interlocked. The brake rod 96 is composed of a front rod portion 96a and a rear rod portion 96b, which are interlocked, and when the brake pedal 68 is depressed, the brake pedal 68 rotates counterclockwise around a support shaft 95 extending in the left-right direction, moving the brake rod 96 forward and activating the brake 97. An electric actuator 98 is also provided to interlock the rear rod portion 96b.

An auxiliary link 99 is interposed in the middle of the brake rod 96. That is, the auxiliary link 99 is provided between the front rod portion 96a and the rear rod portion 96b. This auxiliary link 99 has a swing arm portion 99c that allows the upper shaft 99b to swing back and forth around the lower support shaft 99a, and the rear end plate 98c of the actuator rod 98a, which has a long hole 98b formed therein, is connected to the upper shaft 99b, and is configured by fitting and connecting the boss portion 96c at the rear end of the front rod 96a and the boss portion 96d at the front end of the rear rod 96b to the rear end plate 98c at a position displaced in the axial direction of the upper shaft 99b.

By using such an auxiliary link 99, the operating force can be transmitted reliably even if the axial positions of the rods connected to the upper shaft 99b are misaligned in the axial direction.

1 Running body 3 Rear wheels (drive wheels)
4 Working machine 30 Electric motor 40 Electric motor 50 Battery 50A Replacement battery 57 Mounting frame

Claims (1)

The work vehicle is provided with a working machine (4) mounted on a running body (1), and is characterized in that an electric motor (30, 40) is provided for driving the drive wheels (3) of the running body (1) or the working machine (4), a battery (50) is provided for supplying power to the electric motor (30, 40) and storing the power, and a mounting frame (57) for mounting a replacement battery (50A) is provided at the front of the running body (1) so as to be capable of being raised and lowered.