JP7829338B2 - electric work vehicle - Google Patents

Description

This invention relates to a battery-powered electric work vehicle in which driving power is provided by a motor driven by electricity supplied from a battery.

Patent Document 1 discloses a battery-powered electric work vehicle comprising a work device, a battery, a motor driven by power supplied from the battery, a travel device driven by the motor, and a hydraulic pump driven by the motor.

Japanese Patent Publication No. 2021-104768

In battery-powered work vehicles, the motor noise is quieter than that of conventional engine-powered work vehicles. Therefore, drivers may not notice whether the motor is operating properly or at what rotational speed. The quietness of the motor is an advantage of battery-powered work vehicles. However, drivers accustomed to engine-powered work vehicles rely on engine noise to understand the vehicle's driving and working conditions. The quiet motor noise makes it difficult to perceive these conditions.

Therefore, even with battery-powered electric work vehicles, there is a demand for electric work vehicles that allow the driver to easily perceive the vehicle's driving and working conditions.

The electric work vehicle according to the present invention comprises a machine frame, a support base fixed to the machine frame, an electric motor fixed to the support base, a battery that supplies power to the electric motor, a traveling device driven by the electric motor, a hydraulic pump fixed to the support base, hydraulic equipment supplied with pressurized oil from the hydraulic pump, a driver's seat, and a panel structure positioned in front of the driver's seat, wherein the lower part of the panel structure is connected to at least one of the machine frame and the support base, and the upper part of the panel structure is connected to the upper part of the battery, and comprises a cover member that covers the battery, and a support part connected across the upper part of the panel structure and the upper part of the battery, wherein the cover member is attached to the support part so as to be able to open and close around an opening and closing axis along the left-right direction.

The present invention is based on the inventor's observation that the operating noise (rotational noise) of a hydraulic pump is louder than the rotational noise of a motor, and that the operating noise of the hydraulic pump helps the operator understand the driving and working conditions of the work vehicle. In the configuration of the present invention, the electric motor and the hydraulic pump are fixed to the same support base which is fixed to the machine frame, and furthermore, a panel structure connected to at least one of the machine frame and the support base is positioned in front of the driver's seat. With this configuration, the operating noise of the hydraulic pump is transmitted as solid-conducted sound from the support base through the machine frame, or directly from the support base to the panel structure, and then directly from the panel structure to the operator's ears as air-conducted sound. Since the electric motor and the hydraulic pump are fixed to the support base, the operating noise of the hydraulic pump and the rotational noise of the electric motor are heard as almost the same sound source by the operator. Through this sound, the operator can intuitively understand the driving and working conditions of the work vehicle.
In one preferred embodiment of the present invention, the lower part of the panel structure is connected to the aircraft frame via the support base.

In one preferred embodiment of the present invention, the panel structure comprises a panel assembly to which a notification device for informing the driver of information is attached, and a panel support assembly for supporting the panel assembly. In this configuration, a notification device (meter or display) for informing the driver of various information is attached to the panel assembly that emits the operating sound of the hydraulic pump. Therefore, the driver can understand the driving and working conditions of the work vehicle through a combination of information from the notification device and the operating sound of the hydraulic pump transmitted from the panel assembly.

In one preferred embodiment of the present invention, the support base is a plate member, and the electric motor and the hydraulic pump are fixed to the same surface of the plate member. In this configuration, the rotational noise of the electric motor and the operating noise of the hydraulic pump are integrated and transmitted through the support base, which is made of a plate member with excellent solid-borne sound conductivity, and are ultimately emitted from the panel assembly. As a result, even drivers accustomed to conventional engine-driven work vehicles can understand the vehicle's driving and operating conditions through the operating noise of the hydraulic pump, just as they would in conventional vehicles.

In one preferred embodiment of the present invention, the electric motor and the hydraulic pump are cantilevered to the support base. This allows the rotational noise of the electric motor and the operating noise of the hydraulic pump to be well integrated and transmitted to the panel assembly as solid-borne sound.

Excess load on an electric motor may not be detectable solely by the motor's rotation sound and the hydraulic pump's operating sound. Therefore, in one preferred embodiment of the present invention, a motor load detection unit is provided that detects the excessive load on the electric motor and emits an excessive load detection signal. In response to this excessive load detection signal, at least one of a notification command to alert the driver of the occurrence of the excessive load and a load reduction command to reduce the excessive load is issued. In this configuration, if an excessive load occurs on the electric motor, the driver is notified by a buzzer, lamp, auditory message, visual message, etc., allowing the driver to appropriately address the excessive load. Furthermore, when a load reduction command is output, excessive load reduction processing is performed, such as motor control to increase the torque of the electric motor or reducing the gear ratio in the transmission, thereby appropriately addressing the excessive load on the electric motor.

This is a left side view of the tractor. This is a left side view showing the arrangement of the tractor's powertrain. This is a plan view showing the arrangement and mounting structure of the motor and hydraulic pump. This is an exploded perspective view showing the arrangement and mounting structure of the motor and hydraulic pump. This is a right side view showing the arrangement and mounting structure of the motor, hydraulic pump, and panel structure. This is a front view showing the arrangement and mounting structure of the battery, motor, hydraulic pump, and cover components. This is a perspective view showing the arrangement and mounting structure of the panel structure. This is a functional block diagram showing the configuration of the control system.

The embodiments for carrying out the present invention will be described based on the drawings. In the following description, unless otherwise specified, the direction of arrow F in the figures is considered "forward," the direction of arrow B is considered "backward," the direction of arrow L is considered "left," and the direction of arrow R is considered "right." Furthermore, the direction of arrow U in the figures is considered "up," and the direction of arrow D is considered "down."

[Overall configuration of the tractor]
A tractor, which is an example of an electric work vehicle, will be described as one embodiment. As shown in Figure 1, the tractor is equipped with left and right front wheels 10, left and right rear wheels 11, and a cover member 12.

Furthermore, the tractor comprises a machine frame 2 and a driver's unit 3. The machine frame 2 is supported by the left and right front wheels 10 and left and right rear wheels 11, which constitute the running gear.

The cover member 12 is located at the front of the machine body. The control unit 3 is located behind the cover member 12. In other words, the cover member 12 is positioned in front of the control unit 3.

The driver's unit 3 comprises a protective frame 30, a driver's seat 31, and a steering wheel 32. The driver can sit in the driver's seat 31. This allows the driver to board the driver's unit 3. The left and right front wheels 10 are steered by operating the steering wheel 32. The driver can perform various driving operations from the driver's unit 3.

The tractor is equipped with a battery 4, which is a traction battery. The cover member 12 is configured to pivot around an opening/closing axis Q that runs along the left-right direction of the machine body. This allows the cover member 12 to be opened and closed. When the cover member 12 is closed, the battery 4 is covered by the cover member 12.

As shown in Figure 2, the tractor is equipped with an inverter 14 and an electric motor (hereinafter simply referred to as "motor") 5. The battery 4 supplies power to the inverter 14. The inverter 14 converts the DC power from the battery 4 into AC power and supplies it to the motor 5. The motor 5 is then driven by the AC power supplied by the inverter 14.

As shown in Figure 2, the tractor is equipped with a transmission 16 that includes a power transmission mechanism including a hydrostatic continuously variable transmission (CVT) 15. The hydrostatic CVT 15, also called an HST, has an HST pump 15a and an HST motor 15b. The HST pump 15a is driven by rotational power from the motor 5. When the HST pump 15a is driven, rotational power is output from the HST motor 15b. The hydrostatic CVT 15 is configured so that the rotational power between the HST pump 15a and the HST motor 15b is continuously and smoothly variable in both forward and reverse directions.

The rotational power output from the HST motor 15b is transmitted to the transmission 16. The rotational power transmitted to the transmission 16 is distributed to the left and right rear wheels 11 via the rear differential gear mechanism. Since this tractor is a four-wheel drive type, the rotational power from the transmission 16 is distributed to the left and right front wheels 10 via the front drive shaft 9 and the front differential gear mechanism. This drives the left and right front wheels 10 and the left and right rear wheels 11.

Furthermore, as shown in Figure 2, the tractor is equipped with a mid-PTO shaft 17 and a rear PTO shaft 18. The rotational power output from the motor 5 is distributed to the HST pump 15a, the mid-PTO shaft 17, and the rear PTO shaft 18 via the transmission 16. This causes the mid-PTO shaft 17 and the rear PTO shaft 18 to rotate.

The rotational power of the mid-PTO shaft 17 or the rear PTO shaft 18 drives the work device attached to the mid-PTO shaft 17 or the rear PTO shaft 18. For example, in this embodiment, as shown in Figure 2, a grass cutting device 19 is connected to the mid-PTO shaft 17, and the rotational power of the mid-PTO shaft 17 drives the grass cutting device 19.

As shown in Figure 3, the tractor is equipped with a hydraulic pump 6 alongside the motor 5. The hydraulic pump 6 is driven by the motor 5. The hydraulic pump 6 also supplies pressurized oil to hydraulic actuators (a type of hydraulic equipment) installed on the tractor and to hydraulic actuators installed on the work equipment attached to the tractor.

As shown in Figure 4, the motor output shaft 51 of the motor 5 and the pump input shaft 61 of the hydraulic pump 6 extend in the longitudinal direction of the machine body. A support base 7, which is a plate member, is fixed to the machine frame 2, and the motor 5 and hydraulic pump 6 are fixed to the front surface of the support base 7. Specifically, the motor bracket 50 attached to the motor 5 and the front surface of the support base 7 are in surface contact and bolted together, and the pump bracket 60 attached to the hydraulic pump 6 and the front surface of the support base 7 are in surface contact and bolted together. In other words, the motor 5 and hydraulic pump 6 are cantilevered and supported on the same surface of the support base 7.

Furthermore, a gear transmission mechanism 70 that transmits power from the motor 5 to the hydraulic pump 6 is located on the rear surface of the support base 7. The gear transmission mechanism 70 consists of an output gear 71 attached to the motor output shaft 51 of the motor 5, an input gear 72 attached to the pump input shaft 61 of the hydraulic pump 6, and a gear train 73 that interlocks the output gear 71 and the input gear 72. The support base 7 has a base cover 7a that covers its rear surface, and the base cover 7a is bolted to the support base 7. The gear transmission mechanism 70 is housed in the space created by the support base 7 and the base cover 7a.

With the above configuration, power from the motor 5 is transmitted to the hydraulic pump 6 via the gear transmission mechanism 70, and when the motor 5 is driven, the hydraulic pump 6 is also driven.

As shown in Figure 5, a plate-shaped inverter support section 41 for supporting the inverter 14 is fixed to the aircraft frame 2. Furthermore, a plate-shaped battery support section 40 for supporting the battery 4 is fixed by multiple front supports 42 provided on the inverter support section 41 and a rear support 43 provided on the support base 7. The rear support 43 is a box-shaped structure consisting of multiple plates.

As shown in Figure 5, a panel structure 8 covering the handle post 33 is positioned behind the cover member 12. The cover member 12 is supported by a first support portion 81 and a second support portion 82. The panel structure 8 consists of a panel assembly 8A and a panel support assembly 8B that supports the panel assembly 8A. The panel assembly 8A includes a main panel 85 and an upper panel 86. The panel support assembly 8B includes a vertical support frame 83 and a stay unit 84 consisting of multiple stay members.

As shown in Figure 6, the cover member 12 has a gate-shaped frame portion 12f and a connecting portion 12g in a front view. The frame portion 12f is provided on the inner wall side of the cover member 12. The connecting portion 12g protrudes downward from the lower surface of the upper end of the frame portion 12f. The second support portion 82 is configured in a gate shape that straddles the upper end surface 4a of the battery 4, and the lower end of the second support portion 82 is fixed to the battery 4.

As shown in Figure 6, the first support portion 81 is a projection extending upward from the upper surface of the upper end of the second support portion 82. The first support portion 81 and the connecting portion 12g are connected by a pin, allowing the cover member 12 to swing up and down around the opening/closing axis Q.

Furthermore, left and right side covers 13 are provided below the left and right side walls of the cover member 12. The side covers 13 have a grille 13a (see Figure 1) through which air can pass.

As shown in Figure 5, the front of the driver's unit 3 is equipped with a main panel 85 and a display unit 80 (corresponding to the "notification device" according to the present invention). The display unit 80 is mounted on the top panel portion 85a of the main panel 85. The display unit 80 can notify the driver of various types of information.

As shown in Figures 5 and 7, a vertical support frame 83 is provided between the driver unit 3 and the battery 4. The vertical support frame 83 is supported by the aircraft frame 2 via a rear support 43 and a support base 7, etc. The vertical support frame 83 is gantry-shaped and extends in the vertical direction of the aircraft.

A stay unit 84 is connected to the upper surface of the vertical support frame 83. The upper and lower parts of the top panel portion 85a of the main panel 85 are attached to the stay unit 84. The main panel 85 is supported by the vertical support frame 83 via the stay unit 84. Furthermore, the second support portion 82 and the vertical support frame 83 are connected via the stay unit 84.

Multiple horizontal plates 83a, which function as crossbeams of the vertical support frame 83, are fitted with an electronic control unit (ECU) for controlling the tractor. The ECU is positioned between the top panel portion 85a of the main panel 85 and the vertical support frame 83.

As shown in Figure 8, this tractor is equipped with an electronic control unit (ECU) containing a control unit 100 that controls the behavior of the motor 5 and changes in the transmission state of the transmission 16. The transmission 16 includes a hydrostatic continuously variable transmission 15, a gear shifting mechanism 16A, and a PTO mechanism 16C. The control unit 100 includes a motor control unit 101, a travel control unit 102, and a work control unit 103. The motor control unit 101 controls the output rotational speed of the motor 5 by controlling the inverter 14.
The travel control unit 102 provides control signals to the actuators of the hydrostatic continuously variable transmission 15 and the gear shift mechanism 16A to change the shifting state, such as the gear ratio. The work control unit 103 provides control signals to the actuator of the PTO mechanism 16C to change the power transmission state to the work device.

The motor control unit 101 is equipped with a motor load detection unit 1011 that detects excessive load on the motor 5 and emits an excessive load detection signal. The control unit 100 generates a notification command to alert the motor 5 to the occurrence of excessive load in response to the excessive load detection signal output from the motor load detection unit 1011, and issues an excessive load warning through the display unit 80 and other notification devices such as buzzers and lights. Furthermore, the control unit 100 generates a load reduction command in response to the excessive load detection signal to reduce the excessive load on the motor 5. In response to this load reduction command, the motor control unit 101 controls the motor 5 to increase its torque, or the driving control unit 102 changes the power transmission state of the hydrostatic continuously variable transmission 15, gear shift mechanism 16A, and PTO mechanism 16C to reduce the load on the motor 5. Of course, both load reduction measures may be implemented.

[Another embodiment]
(1) In the embodiment described above, the motor 5 and the hydraulic pump 6 were fixed to the same surface of the support base 7, but they may be fixed to different surfaces.

(2) In the above-described embodiment, the motor 5 and the hydraulic pump 6 were fixed to the support base 7, but the support base 7 may be divided and each part fixed to a separate divided support base.

(3) In the embodiment described above, the sound (vibration) generated by the motor 5 and hydraulic pump 6 is transmitted as solid-conducted sound originating from the support base 7 and emitted by the panel structure 8. Alternatively, a waveguide or similar device may be used in at least a portion of the transmission path of the sound generated by the motor 5 and hydraulic pump 6.

(4) In some work environments, quiet operation may be required. To address this, it is desirable that sound (vibration) absorbing material be selectively inserted into the path of solid-borne sound to minimize noise from the motor 5 and hydraulic pump 6. Ideally, the attachment and detachment of the sound (vibration) absorbing material from the propagation path should be performed by lever operation or similar means.

Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, provided that no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto; they can be modified as appropriate without departing from the purpose of the present invention.

This invention can be used not only for tractors, but also for various electric work vehicles such as combine harvesters, rice transplanters, construction machinery, and off-road vehicles.

2: Aircraft frame 3: Control unit 4: Battery 5: Motor (electric motor)
6: Hydraulic pump 7: Support base 8: Panel structure 8A: Panel assembly 8B: Panel support assembly 12: Cover member 17: Mid PTO shaft 18: Rear PTO shaft 31: Driver's seat 32: Steering wheel 33: Handle post 80: Display unit 81: First support part (support part)
82: Second support part (support part)
83: Vertical support frame 85: Main panel

Claims (6)

The aircraft frame and
A support base fixed to the aforementioned aircraft frame,
An electric motor fixed to the aforementioned support base,
A battery that supplies power to the electric motor,
The traveling device is driven by the aforementioned electric motor,
A hydraulic pump fixed to the aforementioned support base,
A hydraulic device supplied with pressurized oil from the aforementioned hydraulic pump,
The driver's seat and
The system comprises a panel structure positioned in front of the driver's seat,
The lower part of the panel structure is connected to at least one of the aircraft frame and the support base, and the upper part of the panel structure is connected to the upper part of the battery.
The cover member that covers the battery,
It comprises a support portion connected across the upper part of the panel structure and the upper part of the battery,
An electric work vehicle in which the cover member is attached to the support portion so as to be able to open and close around an opening and closing axis that is aligned in the left-right direction . The electric work vehicle according to claim 1, wherein the lower part of the panel structure is connected to the machine frame via the support base. The electric work vehicle according to claim 1, wherein the panel structure comprises a panel assembly to which a notification device for informing the driver of information is attached, and a panel support assembly that supports the panel assembly. The electric work vehicle according to claim 1, wherein the support base is a plate member, and the electric motor and the hydraulic pump are fixed to the same surface of the plate member. The electric work vehicle according to claim 1, wherein the electric motor and the hydraulic pump are cantilevered to the support base. An electric work vehicle according to any one of claims 1 to 5, further comprising a motor load detection unit that detects an excessive load on the electric motor and emits an excessive load detection signal, wherein in response to the excessive load detection signal, at least one of a notification command to notify the occurrence of the excessive load and a load reduction command to reduce the excessive load is emitted.