Work vehicle

Abstract

Provided is a work vehicle that is provided with a brake device (52) that brakes a wheel (2), and is provided with an electric actuator (80) that operates and stops operation of the brake device (52). The electric actuator (80) engages with a support frame (84), and when the electric actuator (80) and the support frame (84) are disengaged, the operation of the brake device (52) by the electric actuator (80) is stopped, thereby removing an electric brake that has caused an operation failure and stopping the braking of the wheel.

Description

Work vehicles

[0001] The present invention relates to a work vehicle for cutting grass.

[0002] Conventionally, vehicles have been known that are equipped with a brake that is operated by the operator and an electric brake that is operated via an electrical signal to brake the drive wheels (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2006-256578

[0004] However, the method described in Patent Document 1 had the problem that if the electric brake malfunctioned due to a broken signal line or a low battery charge, the braking of the drive wheels could not be released and the vehicle could not be moved.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a work vehicle that can release the braking of the wheels even if the electric brake malfunctions.

[0006] The present invention, which has solved the above-mentioned problems, is as follows: That is, the present invention is a work vehicle characterized by being provided with a brake device (52) that brakes the wheels (2), and an electric actuator (80) that activates and releases the brake device (52), the electric actuator (80) engages with a support frame (84), and when the engagement between the electric actuator (80) and the support frame (84) is released, the activation of the brake device (52) by the electric actuator (80) is released.

[0007] According to the present invention, even if the electric actuator (80) stops moving while in operation, the operation of the brake device (52) by the electric actuator (80) can be released.

[0008] 1 is a perspective view of a work vehicle viewed from the front left side; FIG. 2 is a perspective view of the front part of the electric compartment viewed from the rear left side; FIG. 3 is a perspective view of the rear part of the electric compartment viewed from the rear left side; FIG. 4 is a plan view of the electric compartment; FIG. 5 is a plan view of the electric compartment with a battery mounted thereon; FIG. 6 is a left side view illustrating the positional relationship between the front wheels and the brake system; FIG. 7 is a left side view of the brake system; FIG. 8 is a perspective view of the brake system viewed from the front lower side; FIG. 9 is a perspective view of the brake system viewed from the rear left side illustrating a method of installing an electric brake; FIG. 10 is a rear view illustrating a method of installing an electric brake; FIG. 11 is a perspective view of the front part of the electric compartment viewed from the rear left side.

[0009] As shown in FIG. 1 , the work vehicle has a pair of left and right front wheels (wheels) 2 provided at the front lower portion of a body frame 1, and a pair of left and right rear wheels 3 provided at the rear lower portion of the body frame 1.

[0010] A working device 4 for cutting grass growing in the field is provided at the front of the machine frame 1, a control unit 5 on which the operator sits is provided at the rear of the working device 4, a safety frame (ROPS) 6 for protecting the operator is provided at the rear of the control unit 5, a grass collection container 7 for storing the cut grass is provided at the rear of the safety frame 6, and an electric motor room 8 is provided below the grass collection container 7 in which a motor 30 and battery 33, which will be described later, which drive the working device 4, are placed.

[0011] A steering column 10 that supports a steering wheel is provided in front of the driver's seat of the control section 5. A monitor that displays the output rotation speed of the electric motor 30 and the like is provided at the top of the steering column 10, and the bottom is fixed to the front part of the floor.

[0012] A brake pedal (brake operating device) 11 for braking the rotation of the front wheels 2 is provided on the left side of a steering column 10 on the floor, and an accelerator pedal 12 for increasing or decreasing the rotation speed of the front wheels 2 is provided on the right side.

[0013] The upper part of the front wheel 2 is covered with a fender 13, and the fender 13 located on the left side of the cockpit is provided with a brake lever (brake operating device) 14 for braking the rotation of the front wheel 2, and the fender 13 located on the right side of the cockpit is provided with a brake switch 15 for operating an electric actuator 80, which will be described later.

[0014] The rear of the working device 4 and the front of the grass collection container 7 are connected by a chute 16 extending in the front-to-rear direction, and a blower for exhausting air into the chute 16 is provided in the middle of the front-to-rear direction of the chute 16.

[0015] A pair of left and right link arms 18 are provided at the front of the left and right walls of the grass collection container 7. The front parts of the link arms 18 are fixed to the left and right parts of the safety frame 6 so as to be able to swing freely, and the safety frame 6 and the link arms 18 are connected by lifting parts 19 such as hydraulic cylinders. In addition, the rear part of the bottom wall of the grass collection container 7 rests on a horizontal frame 21A of a support frame 21, which will be described later. This allows the grass collection container 7 to be raised and lowered by driving the lifting parts 19.

[0016] As shown in Figures 2 and 3, the front electric motor chamber 8A of the electric motor chamber 8 is provided with a working electric motor 30 that drives the working device 4 and a traveling electric motor 31 that rotates the front wheels 2, and the rear electric motor chamber 8B is provided with a battery 33 that stores electricity to be supplied to the electric motor 30 etc.

[0017] In a plan view, the electric motor 30 is provided to the left of the center line in the left-right direction of the body frame 1, and the electric motor 31 is provided to the right of the center line in the left-right direction of the body frame 1. This reduces the weight difference between the weight applied to the left of the center line in the left-right direction of the body frame 1 and the weight applied to the right of the center line in the left-right direction of the body frame 1, thereby improving steering performance.

[0018] When viewed from the side, a support frame 20 extending upward from the body frame 1 is provided in the partition between the front electric chamber 8A and the rear electric chamber 8B, and a support frame 21 extending upward from the body frame 1 is provided at the rear end of the rear electric chamber 8B.

[0019] The support frame 20 is formed of a left vertical frame 20L extending upward from the middle of the left side of the body frame 1, a right vertical frame 20R extending upward from the middle of the right side of the body frame 1, and a horizontal frame 20A extending in the left-right direction connecting the upper parts of the left vertical frame 20L and the right vertical frame 20R.

[0020] The support frame 21 is formed of a left vertical frame 21L extending upward from the rear end of the left side of the body frame 1, a right vertical frame 21R extending upward from the rear end of the right side of the body frame 1, a horizontal frame 21A extending in the left-right direction connecting the upper parts of the left vertical frame 21L and the right vertical frame 21R, and a horizontal frame 21B extending in the left-right direction connecting the middle parts of the left vertical frame 21L and the right vertical frame 21R. The left part of the horizontal frame 21B extends further left than the left vertical frame 21L, and the right part extends further right than the right vertical frame 21R.

[0021] The middle portion of the left vertical frame 20L and the left end portion of the horizontal frame 21B are connected by a left front-rear frame 22L extending in the front-rear direction, and the middle portion of the right vertical frame 20R and the right end portion of the horizontal frame 21B are connected by a right front-rear frame 22R also extending in the front-rear direction. This allows the rear portion of the battery 33 to be located above the drive shaft of the rear wheel 3, preventing the vehicle frame 1 from being significantly deformed.

[0022] The upper part of the left vertical frame 20L and the middle part of the left vertical frame 23 provided at the rear of the control unit 5 are connected by a left front-rear frame 24 extending in the fore-and-aft direction, and the upper part of the right vertical frame 20R of the support frame 20 and the middle part of the right vertical frame 23 provided at the rear of the control unit 5 are connected by a right front-rear frame 24 extending in the fore-and-aft direction.

[0023] 4, the longitudinal direction of the electric motor 30 is aligned along the front-rear direction. The electric motor 31 is aligned adjacent to the right side of the electric motor 30, and the longitudinal direction of the electric motor 31 is aligned along the front-rear direction.

[0024] A radiator 40 that cools the water that cools the electric motor 30 and other components is provided on the outside of the left wall of the electric motor chamber 8, and a fan 41 that blows outside air toward the electric motor chamber 8 is provided between the radiator 40 and the electric motor 30. A circular opening (not shown) is formed in the left wall of the electric motor chamber 8 at a location facing the fan 41. This makes it possible to suppress a rise in temperature of the electric motor 30 and other components, thereby preventing malfunctions of the electric motor 30 and other components.

[0025] An auxiliary battery 42 that stores power to be supplied to the monitor of the control unit 5 is provided on the outside of the part of the right wall of the electric motor compartment 8 that faces the radiator 40. This makes it possible to reduce the weight difference between the left and right parts of the work vehicle.

[0026] As shown in Figures 3 and 5, the front part of the mounting frame 34 that secures the upper part of the battery 33 is removably fixed to the horizontal frame 20A of the support frame 20 by fastening members such as bolts, and the rear part is removably fixed to the horizontal frame 21A of the support frame 21 by fastening members such as bolts.

[0027] The left mounting frame 35 that secures the lower portion of the battery 33 is placed on the left front-rear frame 22L, and the right mounting frame 35 is placed on the right front-rear frame 22R.

[0028] Openings 34A are formed in the front and rear of the mounting frame 34, through which hanging hooks can be inserted when replacing the battery 33. This allows the battery 33 to be easily attached to and detached from the support frames 20 and 21, and the battery 33 can be easily replaced.

[0029] <Brake System> As shown in FIGS. 6 to 8 , the brake system 100 that brakes the rotation of the front wheels 2 is made up of a brake pedal 11, a brake lever 14, an electric actuator 80 operated by a brake switch 15, a rotary shaft 50 extending in the left-right direction that is rotated by, for example, stepping on the brake pedal 11, and a brake device 52 that is operated by the rotation of the rotary shaft 50.

[0030] The tip of an arm 50A provided on the left side of the rotating shaft 50 and the tip of an arm 52A provided on the lower part of the braking device 52 for moving a brake pad are connected via a rod 51 extending in the vertical direction. This allows the rotating shaft 50 to rotate, moving the brake pad of the braking device 52 and braking the rotation of the front wheel 2.

[0031] The base of the brake pedal 11 is pivotally supported on a support shaft 60 extending in the left-right direction. The rear of the base of the brake pedal 11 is connected to the tip of an arm 50B provided on the left part of the rotating shaft 50 via a link 61 extending rearward and downward and a link 62 extending in the front-rear direction.

[0032] The rear portion of link 61 and the front portion of link 62 are rotatably fixed to a pin 64 extending in the left-right direction at the tip of an arm 63A provided on a rotary shaft 63 extending in the left-right direction. As a result, when the brake pedal 11 is depressed, the rotary shaft 50 rotates clockwise when viewed from the axis of the rotary shaft 50, moving the rod 51 upward and activating the brake device 52 to brake the rotation of the front wheel 2. When the brake pedal 11 is released, the rotary shaft 50 rotates counterclockwise when viewed from the axis of the rotary shaft 50, moving the rod 51 downward and activating the brake device 52.

[0033] The base of the brake lever 14 is swingably supported on a support shaft 70 extending in the left-right direction. The lower part of the base of the brake lever 14 is connected to the tip of an arm 50B provided on the left part of the rotation shaft 50 via a link 71 extending in the up-down direction and a link 72 extending in the front-rear direction.

[0034] An opening 71A having a long axis in the vertical direction is formed at the bottom of the link 71, and a pin 74 extending in the left-right direction at the front of an arm 73A provided on the left side of the rotating shaft 73 is engaged in the opening 71A so as to be movable in the vertical direction.

[0035] The front portion of the link 72 is rotatably fixed to a pin 75 extending in the left-right direction at the bottom of an arm 73B provided on the right portion of the rotating shaft 73. As a result, when the brake lever 14 is pulled up, the rotating shaft 50 rotates clockwise when viewed from the axis of the rotating shaft 50, moving the rod 51 upward and activating the brake device 52 to brake the rotation of the front wheel 2. When the brake lever 14 is released from being pulled up, the rotating shaft 50 rotates counterclockwise when viewed from the axis of the rotating shaft 50, moving the rod 51 downward and terminating the activation of the brake device 52.

[0036] When the brake switch 15 on the control unit 5 is pressed, the piston rod 80A of the electric actuator 80, which moves up and down, rises, and when the brake switch 15 is released, the piston rod 80A of the electric actuator 80 descends.

[0037] A lower portion of the piston rod 80A is connected via a link 81 extending in the vertical direction to the tip of an arm 50C provided between the arms 50A and 50B of the rotating shaft 50. As a result, when the brake switch 15 is pressed, the rotating shaft 50 rotates clockwise when viewed from the axis of the rotating shaft 50, moving the rod 51 upward and activating the brake device 52 to brake the rotation of the front wheel 2. When the brake switch 15 is released, the rotating shaft 50 rotates counterclockwise when viewed from the axis of the rotating shaft 50, moving the rod 51 downward and activating the brake device 52.

[0038] 9 and 10 , the upper part of the electric actuator 80 is fixed to a support frame 84 made of channel steel extending in the front-rear direction and provided in the front motor chamber 8A via a plate-shaped support member 83 extending in the up-down direction. The lower part of the piston rod 80A of the electric actuator 80 and the upper part of the link 81 are detachably fixed with a pin 82, and the upper part of the electric actuator 80 and the support member 83 are detachably fixed with a pin 82B. As a result, in the event of a malfunction of the electric actuator 80, the electric actuator 80 can be easily replaced by pulling out the pins 82A and 82B.

[0039] The support member 83 is inserted from bottom to top through openings 84A, which are formed on the lower and upper sides of the support frame 84 and have a long axis in the front-to-rear direction, and an engaging member 83A, such as a rod, extending in the front-to-rear direction is provided at the upper end of the support member 83. The length of the engaging member 83A in the front-to-rear direction is longer than the length of the opening 84A in the front-to-rear direction. This prevents the electric actuator 80 from falling excessively and colliding with other components when a pin 86, which will be described later, is pulled out.

[0040] On the left side of the support frame 84, there are provided a pin 86 extending in the left-right direction and inserted into a circular opening 84B formed in the left side of the support frame 84 and a circular opening 83B formed in the support member 83, and a handle 87 fixed to the left part of the pin 86. The left part of the pin 86 is fixed to the inner periphery of the handle 87 so as to be movable in the left-right direction.

[0041] A protrusion 86A formed by a pin extending in the vertical direction is formed at the middle of the pin 86, and a biasing component 88 such as a spring that presses the pin 86 from the support frame 84 toward the support member 83 is provided between the right part of the handle 87 and the left part of the protrusion 86A. This prevents the pin 86 inserted through the openings 83B and 84B from being pulled out of the openings 83B and 84B due to vibrations during travel, and allows the electric actuator 80 to be suspended in a predetermined position.

[0042] The clockwise rotation angle of the rotating shaft 50 when the brake pedal 11 is depressed and the clockwise rotation angle of the rotating shaft 50 when the brake lever 14 is pulled up are set to be larger than the clockwise rotation angle of the rotating shaft 50 when the brake switch 15 is pressed down to drive the electric actuator 80 and move the piston rod 80A upward. As a result, if the electric actuator 80 malfunctions and the piston rod 80A cannot be moved downward, making it impossible to release the braking of the brake device 52, the brake pedal 11 can be depressed or the brake lever 14 pulled up to reduce the external force acting on the engagement portion between the pin 86 and the opening 83B or opening 84B, and the pin 86 can be pulled out of the opening 83B or opening 84B.

[0043] 11, it is preferable that the brake device 52, rod 51, etc. can be visually observed through the gap between the safety frame 6 and the motor chamber 8. This makes it easy to confirm that the electric actuator 80 has malfunctioned.

[0044] A rotation sensor that measures the rotation angle of the rotation shaft 50 is provided on one side of the rotation shaft 50, and a stroke sensor that measures the vertical movement of the piston rod 80A is provided on the electric actuator 80, and if the measurement value of the rotation sensor does not change when the brake pedal 11 is depressed or released, or if the measurement value of the stroke sensor does not change when the brake switch 15 is pressed or released, a warning is displayed on the monitor of the operation unit 5. This allows the operator to be promptly notified of a malfunction of the electric actuator 80, etc.

Claims

1. A work vehicle comprising: a brake device (52) for braking wheels (2); an electric actuator (80) for activating and deactivating said brake device (52); said electric actuator (80) engaging with a support frame (84); and when the engagement between said electric actuator (80) and said support frame (84) is released, the activation of said brake device (52) by said electric actuator (80) is released.

2. A work vehicle as described in claim 1, further comprising a brake operating device (11, 14) for allowing an operator to directly manually operate the brake device (52), wherein when the brake device (52) is operated by the brake operating device (11, 14), the engagement between the electric actuator (80) and the support frame (84) can be released, and when the brake device (52) is not operated by the brake operating device (11, 14), the release of the engagement between the electric actuator (80) and the support frame (84) is restricted.

3. A work vehicle as set forth in claim 2, wherein the electric actuator (80) is provided with a piston rod (80A) that moves when actuated, the electric actuator (80) engages with the support frame (84) via a support member (83) and a pin (86), the pin (86) is inserted through the support frame (84) and the support member (83) in a direction intersecting the moving direction of the piston rod (80A), and the engagement between the electric actuator (80) and the support frame (84) is released by pulling out the inserted pin (86) from the support member (83).

4. A work vehicle as described in claim 3, wherein the pin (86) is inserted into an opening (83B) formed in the support member (83), the brake operating device (11, 14) and the electric actuator (80) operate the brake device (52) via a common rotating shaft (50), and the rotation angle of the rotating shaft (50) when the brake operating device (11, 14) is operated is set larger than the rotation angle of the rotating shaft (50) when the electric actuator (80) is activated.

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