JP6811734B2 - Work vehicle - Google Patents

Description

The present disclosure relates to a work vehicle having a boom.

It is known that a work machine provided in a work vehicle such as a backhoe or a wheel loader has at least a boom that is rotatably attached to the vehicle in the vertical direction and an arm that is rotatably received at the tip of the boom. There is.

For example, Patent Document 1 discloses a work vehicle in which the work machine is a hydraulic excavator. An arm is attached to the tip of the boom of the work machine, and a bucket is attached to the tip of the arm. The power source of the work machine is an engine, and a fuel cylinder as a fuel supply source for the engine is arranged at the base end of the boom.

Jikkenhei 3-123728 Gazette

In a work vehicle in which a fuel cylinder is mounted on a boom constituting the work machine, the weight of the work machine changes depending on the remaining amount of fuel in the fuel cylinder. Therefore, even if the operating amount of the operating lever is the same, the operating speed of the working machine changes depending on whether the fuel is full or the remaining amount of fuel is low, and the operability deteriorates.

When the fuel cylinder is placed in the vehicle, the vehicle tends to be large. In particular, in a configuration in which the vehicle has a lower traveling body and an upper rotating body mounted on the lower traveling body, and a work machine is attached to the upper rotating body, the space for arranging the fuel cylinder is provided in the upper rotating body. This is necessary, and the upper swivel body becomes larger in the rear, and the turning radius becomes larger. This goes against the requirement to reduce the turning radius. Further, when the fuel cylinder is arranged in the vehicle, the center of gravity of the vehicle tends to change according to the remaining amount of the fuel cylinder, which is not always preferable.

The present disclosure has focused on such a problem, and an object of the present disclosure is to provide a work vehicle in which the vehicle size can be reduced and the operability is improved.

The work vehicle of the present disclosure includes a boom mounted so as to be rotatable in the vertical direction, a boom cylinder for driving the boom, a gas engine as a power source for supplying work oil to the boom cylinder, and the gas engine. A gas cylinder which is a fuel supply source of the above and is arranged at the base end portion of the boom, a fuel remaining amount acquisition means for acquiring a value corresponding to the fuel remaining amount of the gas cylinder, and the fuel remaining amount acquisition means. The flow control means for controlling the flow rate of the work oil supplied to the boom cylinder according to the value corresponding to the remaining amount of fuel is provided.

With this configuration, the flow rate of the work oil supplied to the boom cylinder is controlled according to the value corresponding to the fuel remaining amount acquired by the fuel remaining amount acquisition means, so that the boom operation when the fuel remaining amount is large. It is possible to control so as to reduce or eliminate the difference between the speed and the operating speed of the boom when the remaining fuel amount is low, and it is possible to improve the operability.
Further, the space of the vehicle (upper turning body) can be effectively utilized, the protrusion width at the rear of the vehicle body can be reduced, the turning radius can be reduced, and the vehicle size can be reduced.
Furthermore, if the gas cylinder is placed at the base end of the boom, the gas cylinder will be placed near the center of the vehicle (upper swivel body), reducing fluctuations in the liquid level of the liquid fuel in the gas cylinder and suppressing false detection. You may be able to.

Side view showing the work vehicle of the 1st embodiment and the 2nd embodiment The figure which shows the hydraulic circuit in the work vehicle of 1st Embodiment Explanatory drawing about mapping data of 1st Embodiment The figure which shows the hydraulic circuit in the work vehicle of 2nd Embodiment Explanatory drawing about mapping data of 2nd Embodiment

<First Embodiment>
Hereinafter, the work vehicle of the first embodiment of the present disclosure will be described with reference to the drawings.

[Structure of work vehicle]
As shown in FIG. 1, a schematic structure of a backhoe 1 as an example of a work vehicle will be described. However, the work vehicle is not limited to the backhoe 1, and may be another vehicle such as a wheel loader. The backhoe 1 includes a lower traveling body 2, a working machine 3, and an upper rotating body 4.

The lower traveling body 2 is driven by receiving power from the engine 42 to drive the backhoe 1. The lower traveling body 2 includes a pair of left and right crawlers 21 and 21 and a pair of left and right traveling motors 22R and 22L. The left and right traveling motors 22R and 22L, which are hydraulic motors, drive the left and right crawlers 21 and 21, respectively, to enable the backhoe 1 to move forward and backward. Further, the lower traveling body 2 is provided with a blade 23 and a blade cylinder 24 which is a hydraulic actuator for rotating the blade 23 in the vertical direction.

The work machine 3 is driven by receiving power from the engine 42 to perform excavation work such as earth and sand. The work machine 3 includes a boom 31, an arm 32, and a bucket 33, and by driving these independently, excavation work is possible. The boom 31, arm 32, and bucket 33 correspond to working portions, respectively, and the backhoe 1 has a plurality of working portions.

The boom 31 is rotated by a boom cylinder 31a whose base end portion is rotatably supported by the front portion of the upper swivel body 4 in the vertical direction and which can be expanded and contracted. Further, the arm 32 is rotated by an arm cylinder 32a whose base end portion is supported by the tip end portion of the boom 31 and which can be expanded and contracted. Then, the bucket 33 is rotated by a bucket cylinder 33a whose base end portion is supported by the tip end portion of the arm 32 and which can be expanded and contracted. The boom cylinder 31a, arm cylinder 32a, and bucket cylinder 33a correspond to a hydraulic actuator that drives a working unit. An articulated structure is formed by the boom 31 and the arm 32, and the boom 31 is arranged on the most proximal side among the elements constituting the articulated structure.

The upper swivel body 4 swivels the working machine 3. A control unit 41, an engine 42, a swivel base 43, a swivel motor 44, and the like are arranged on the upper swivel body 4. The swivel motor 44, which is a hydraulic motor, drives the swivel base 43 to swivel the work machine 3. Further, the upper swing body 4 is provided with a plurality of hydraulic pumps (not shown in FIG. 1) driven by the engine 42. These hydraulic pumps supply hydraulic oil to the boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a.

A driver's seat 411 is arranged in the control unit 41. A pair of work operation levers 421 and 412 are arranged on the left and right sides of the driver's seat 411, and a pair of traveling levers 413 and 413 are arranged in front of the cockpit 411. The operator controls the engine 42, each hydraulic motor, each hydraulic actuator, etc. by operating the work operation levers 421, 412, traveling levers 413, 413, etc. while seated in the driver's seat 411, and travels, turns, and works. Etc. can be performed.

As shown in FIG. 1, the backhoe 1 of the first embodiment uses a gas engine 42 as the engine 42. The gas cylinder 6 which is the fuel supply source of the gas engine 42 is arranged at the base end portion of the boom 31. If it is the base end of the boom 31, the shaking is smaller than when it is placed at the tip of the boom 31, and the height of the gas cylinder 6 of the boom 31 is lower, so that the gas cylinder 6 can be easily replaced. Become. In the present embodiment, LPG (Liquefied Petroleum Gas) is used as the fuel, but the present invention is not limited to this, and can be changed as appropriate.

[Basic configuration of hydraulic circuit]
The hydraulic circuit 5 included in the backhoe 1 will be described with reference to FIG. The hydraulic circuit 5 includes a hydraulic actuator (boom cylinder 31a, arm cylinder 32a, bucket cylinder 33a, left traveling motor 22L, right traveling motor 22R, swivel motor 44), a hydraulic pump 50, a direction switching valve 51, and a pilot pump 52. And a remote control valve 53.

As shown in FIG. 2, the hydraulic pump 50 discharges the work oil supplied to the hydraulic actuator. The hydraulic pump 50 is driven by the engine 42 (see FIG. 1) as a power source. In the first embodiment, a plurality of hydraulic pumps 50 are provided, and the first hydraulic pump 50a and the second hydraulic pump 50b are provided. The first hydraulic pump 50a mainly supplies working oil to the boom cylinder 31a, the bucket cylinder 33a, and the left traveling motor 22L. The second hydraulic pump 50b mainly supplies working oil to the right traveling motor 22R, the arm cylinder 32a, and the swivel motor 44. The number of hydraulic pumps 50 can be changed according to the design.

The direction switching valve 51 is provided corresponding to each hydraulic actuator, and is configured to be able to switch the direction and flow rate of the work oil supplied from the hydraulic pump 50 to the hydraulic actuator. The plurality of directional control valves 51 are collectively called a control valve. Specifically, in the first embodiment, the boom direction switching valve 51a corresponding to the boom cylinder 31a, the bucket direction switching valve 51b corresponding to the bucket cylinder 33a, and the left traveling motor corresponding to the left traveling motor 22L. The directional switching valve 51c, the directional switching valve 51d for the right traveling motor corresponding to the right traveling motor 22R, the directional switching valve 51e for the arm corresponding to the arm cylinder 32a, and the directional switching valve 51f for the swivel motor 44. , Are provided.

The pilot pump 52 discharges pilot oil as a command input to the directional control valves 51 (51a, 51b, 51c, 51d, 51e, 51f). The pilot pump 52 is driven by the engine 42 as a power source. In FIG. 2, the oil passage of the work oil supplied to the hydraulic actuator is shown by a solid line, and the oil passage of the pilot oil supplied to the direction switching valve 51 is shown by a broken line.

The remote control valve 53 is configured to be able to switch the direction of the pilot oil input to the direction switching valve 51 according to the operation of the operating levers 421 and 413. The remote control valve 53 is provided for each hydraulic actuator and the corresponding directional control valve 51. For example, as shown in FIG. 2, a boom remote control valve 53a corresponding to a work operation lever 412 for driving the boom 31 is provided, and the boom remote control valve 53a supplies the boom direction switching valve 51a. Switch the direction of pilot oil as a command. Although not shown in FIG. 2, a remote control valve 53 corresponding to each of the direction switching valves 51b, 51c, 51d, 51e, and 51f is provided.

[Basic operation of hydraulic circuit]
Next, the basic operation of the hydraulic circuit 5 will be described.
As shown in FIG. 2, the hydraulic pump 50 and the pilot pump 52 are driven by the drive of the gas engine 42, and the working oil (pressure oil) under pressure is supplied to each direction switching valve 51, and each remote controller is used. Pilot oil is supplied to the valve 53. For example, when the work operation lever 412 for driving the boom 31 is operated in the first operation direction, the boom remote control valve 53a is interlocked with the movement of the work operation lever 412. When the boom remote control valve 53a moves, pilot oil is supplied as a command to the first pilot port of the boom direction switching valve 51a. The valve body of the boom directional control valve 51a is moved by the pilot oil, and the working oil supplied from the hydraulic pump 50 is supplied to the boom cylinder 31a. When the work oil is supplied to the boom cylinder 31a, the boom 31 operates in a direction corresponding to the first operation direction of the work operation lever 412 (for example, ascending). When the work operation lever 412 for driving the boom 31 is operated in the second operation direction opposite to the first operation direction, pilot oil is supplied to the second pilot port of the boom direction switching valve 51a and operates. Oil is supplied to the boom cylinder 31a, and the boom 31 operates in a direction corresponding to the second operation direction of the work operation lever 412 (for example, lowering).

[Fuel level acquisition means]
In the present disclosure, the following configuration is added to the above basic configuration. That is, the fuel remaining amount acquisition means 7 for acquiring the value corresponding to the fuel remaining amount of the gas cylinder 6 is provided. In the example shown in FIG. 2, the fuel remaining amount acquisition means 7 is a pressure sensor 70 that detects the oil pressure on the bottom side of the boom cylinder 31a as a value corresponding to the fuel remaining amount. The weight of the working machine 3 including the fuel of the gas cylinder 6 acts on the boom cylinder 31a. When the remaining amount of fuel in the gas cylinder 6 is large, the oil pressure on the bottom side of the boom cylinder 31a becomes high, and as the remaining amount of fuel in the gas cylinder 6 decreases, the oil pressure on the bottom side of the boom cylinder 31a decreases. The oil pressure on the bottom side of the gas cylinder 6 is used as a value corresponding to the remaining amount of fuel in the gas cylinder 6. The detection signal of the pressure sensor 70 is input to the ECU 54.

[Flow control means]
The flow rate control means 8 for controlling the flow rate of the working oil supplied to the boom cylinder 31a is provided according to the value corresponding to the remaining fuel amount acquired by the fuel remaining amount acquisition means 7. In the example shown in FIG. 2, the flow rate control means 8 is a detection result of the flow rate control valve 80 that controls the flow rate of the oil passage flowing between the boom cylinder 31a and the boom direction switching valve 51a, and the fuel remaining amount acquisition means 7. It has a flow rate valve control unit 81 that controls the flow rate control valve 80 by using a command value according to the above. In the flow valve control unit 81, the larger the remaining fuel amount, the larger the flow rate of the oil passage flowing between the boom cylinder 31a and the boom direction switching valve 51a, and the smaller the remaining amount of fuel, the larger the boom cylinder 31a. The flow rate control valve 80 is controlled so that the flow rate of the oil passage flowing between the and the boom direction switching valve 51a is relatively small.

In the first embodiment, the mapping data 82 is provided in order to keep the operating speed of the boom 31 constant regardless of the remaining fuel amount. The mapping data 82 is data in which a value corresponding to the remaining fuel amount detected by the fuel remaining amount acquisition means 7 and a command value for controlling the flow rate of the working oil flowing through the boom cylinder 31a are associated with each other. For example, as shown in FIG. 3, the oil pressure on the bottom side of the boom cylinder 31a and the command value (current value) corresponding to the throttle amount of the flow control valve 80 are associated with each other. The flow valve control unit 81 determines a command value (throttle amount of the flow control valve 80) corresponding to the detected oil pressure on the bottom side of the boom cylinder 31a with reference to the mapping data 82, and uses the determined command value. The flow control valve 80 is controlled. In the present embodiment, the command value is a current value input to the flow rate control valve 80, but is not limited to this, and can be appropriately changed to a voltage value or other command value. The mapping data 82 is in a table format, a function format, or any other form as long as it is data that associates a value corresponding to the remaining fuel amount with a command value for controlling the flow rate of the working oil flowing through the boom cylinder 31a. It may be implemented.

Although the mapping data 82 is provided in the first embodiment, the mapping data 82 can be omitted. The flow rate control means 8 may be configured to set one or a plurality of threshold values with respect to a value corresponding to the remaining amount of fuel, and to switch and control one or a plurality of command values according to the threshold values.

<Second Embodiment>
The second embodiment will be described below. The same configurations as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the second embodiment, the fuel remaining amount acquisition means 107 and the flow rate control means 108 are changed.

[Fuel level acquisition means]
As shown in FIG. 4, the fuel remaining amount acquisition means 107 of the second embodiment is a level sensor 170 provided in the gas cylinder 6 and using a float for detecting the level of the liquid fuel. The level sensor 170 can detect the remaining amount of fuel by detecting the position of the float.

[Flow control means]
As shown in FIG. 4, the flow rate control means 108 of the second embodiment includes a pressure reducing valve 180 that controls the pressure of the pilot oil from the boom remote control valve 53a to the boom direction switching valve 51a, and the fuel remaining amount acquisition means 107. It has a pressure reducing valve control unit 181 that controls the pressure reducing valve 180 using a command value according to the detection result of. In the pressure reducing valve control unit 181, the more fuel remaining, the higher the pressure of the pilot oil from the boom remote control valve 53a to the boom directional control valve 51a, and the smaller the fuel remaining, the more the boom remote control valve. The pressure reducing valve 180 is controlled so that the pressure of the pilot oil from 53a to the boom direction switching valve 51a becomes relatively small. Generally, the directional control valve 51 including the directional control valve 51a for a boom is a work oil supplied to a corresponding hydraulic actuator (boom cylinder 31a, etc.) by the input pilot oil pressure (also called pilot pressure). It is configured to change the flow rate. That is, if the pilot pressure is high, the flow rate of the work oil flowing through the hydraulic actuator increases, and conversely, if the pilot pressure is low, the flow rate of the work oil flowing through the hydraulic actuator decreases. Therefore, the flow rate control means 108 changes the flow rate of the working oil flowing through the boom cylinder 31a by changing the pilot pressure reaching the boom direction switching valve 51a according to the remaining amount of fuel.

In the mapping data 182, the detection result of the level sensor 170 and the command value (current value) input to the flow control valve 80 are associated with each other. The pressure reducing valve control unit 181 determines a command value (decompression amount of the pressure reducing valve control unit 181) corresponding to the value detected by the level sensor 170 with reference to the mapping data 182, and the pressure reducing valve 180 is determined by the determined command value. To control. Other than that, what has been described in the description of the first embodiment can be appropriately applied. In the present embodiment, the command value is a current value input to the pressure reducing valve 180, but the command value is not limited to this, and can be appropriately changed to a voltage value or other command value.

As described above, the work vehicles of the first embodiment and the second embodiment supply working oil to the boom 31 rotatably attached in the vertical direction, the boom cylinder 31a for driving the boom 31, and the boom cylinder 31a. The gas engine 42, which is the power source for the operation, and the gas cylinder 6 which is the fuel supply source of the gas engine 42 and is arranged at the base end of the boom 31, and the values corresponding to the remaining fuel amount of the gas cylinder 6 are acquired. The flow rate control means 8 that controls the flow rate of the work oil supplied to the boom cylinder 31a according to the values corresponding to the fuel remaining amount acquisition means 7, 107 and the fuel remaining amount acquisition means 7, 107. , 108 and.

Since the gas cylinder is located at the base end of the boom, the weight of the work equipment changes according to the amount of fuel remaining in the gas cylinder. A flow rate of working oil corresponding to the amount of operation of the operating lever is supplied to the boom cylinder that drives the boom. If the operating amount of the operating lever is the same, that is, if the flow rate of the working oil supplied to the boom cylinder that drives the boom is the same, the operating speed of the boom slows down when the working machine is heavy, and conversely, the working machine moves. When it is light, the operating speed of the boom becomes high, and the operability is impaired.
With the above configuration, the flow rate of the work oil supplied to the boom cylinder 31a is controlled according to the value corresponding to the fuel remaining amount acquired by the fuel remaining amount acquiring means 7, 107, so that when the fuel remaining amount is large. It is possible to control so as to reduce or eliminate the difference between the operating speed of the boom 31 and the operating speed of the boom 31 when the remaining fuel amount is low, and it is possible to improve the operability.
Further, the space of the vehicle (upper turning body 4) can be effectively utilized, the protrusion width at the rear of the vehicle body can be reduced, the turning radius can be reduced, and the vehicle size can be reduced.
Further, if the gas cylinder 6 is arranged at the base end portion of the boom 31, the gas cylinder 6 is arranged near the center of the vehicle (upper swivel body 4), and the liquid level fluctuation of the liquid fuel in the gas cylinder 6 is reduced. , False detection may be suppressed.

In the first embodiment, the fuel remaining amount acquisition means 7 is a pressure sensor 70 that detects the oil pressure P on the bottom side of the boom cylinder 31a as a value corresponding to the fuel remaining amount.

When the remaining amount of fuel in the gas cylinder 6 is large, the oil pressure on the bottom side of the boom cylinder 31a becomes high, and as the remaining amount of fuel in the gas cylinder 6 decreases, the oil pressure on the bottom side of the boom cylinder 31a decreases. Since this is used in the above configuration, it is possible to detect a value corresponding to the remaining amount of fuel in the gas cylinder 6. Nevertheless, in the configuration in which the remaining amount of fuel is detected by the float in the container of the gas cylinder 6, a measurement error due to the fluctuation of the fuel level is included, but in the above configuration, such a measurement error can be eliminated. It becomes.

In the second embodiment, the fuel remaining amount acquisition means 107 is a level sensor 170 provided in the gas cylinder 6 and using a float for detecting the level of the liquid fuel.

According to this configuration, it is possible to directly detect the remaining amount of liquid fuel.

In the first embodiment and the second embodiment, there are mapping data 82 and 182 in which the value corresponding to the remaining fuel amount and the command value for controlling the flow rate of the working oil flowing through the boom cylinder 31a are associated with each other. Then, the flow rate control means 8 and 108 determine the command value corresponding to the value corresponding to the fuel remaining amount acquired by the fuel remaining amount acquisition means 7 and 107 based on the mapping data 82 and 182, and use the determined command value. Is configured to control.

According to this configuration, if the mapping data 82 and 182 are configured so that the operating speed of the boom 31 is constant or within a predetermined speed range regardless of the remaining fuel amount, the operability can be improved.

In the first embodiment, the boom direction switching valve 51a capable of switching the direction of the work oil supplied to the boom cylinder 31a is provided, and the flow rate control means 8 is between the boom cylinder 31a and the boom direction switching valve 51a. It has a flow rate control valve 80 that controls the flow rate of the oil passage that flows through the oil passage, and a flow rate valve control unit 81 that controls the flow rate control valve 80 by using a command value according to the detection result of the fuel remaining amount acquisition means 7. This is a preferable specific example of the flow rate control means.

In the second embodiment, the direction of the boom direction switching valve 51a that can switch the direction of the work oil supplied to the boom cylinder 31a and the direction of the pilot oil supplied to the boom direction switching valve 51a can be switched according to the operation. The boom remote control valve 53a and the flow control means 108 include a pressure reducing valve 180 for controlling the pressure of pilot oil from the boom remote control valve 53a to the boom direction switching valve 51a, and a fuel remaining amount acquisition means 107. It has a pressure reducing valve control unit 181 that controls the pressure reducing valve 180 using a command value according to the detection result of. This is a preferable specific example of the flow rate control means.

Although the present embodiment of the present disclosure has been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present disclosure is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

It is possible to adopt the structure adopted in each of the above embodiments in any other embodiment. The specific configuration of each part is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present disclosure.

For example, the fuel remaining amount acquisition means 7 in the first embodiment can be applied as the fuel remaining amount acquisition means in the second embodiment, and the flow rate control means 8 in the first embodiment can be used as the flow rate control means in the second embodiment. Applicable as.

31 Boom 31a Boom cylinder 42 Gas engine 51a Boom direction switching valve 53a Boom remote control valve 6 Gas cylinder 7,107 Fuel level acquisition means 70 Pressure sensor 170 Level sensor 8,108 Flow control means 80 Flow control valve 81 Flow valve control unit 82,182 Mapping data 180 Pressure reducing valve 181 Pressure reducing valve control unit

Claims (6)

With a boom mounted rotatably in the vertical direction,
The boom cylinder that drives the boom and
A gas engine that is a power source for supplying working oil to the boom cylinder,
A gas cylinder that is a fuel supply source for the gas engine and is arranged at the base end of the boom.
A fuel remaining amount acquisition means for acquiring a value corresponding to the fuel remaining amount of the gas cylinder, and
A work vehicle including a flow rate control means for controlling the flow rate of work oil supplied to the boom cylinder according to a value corresponding to the remaining fuel amount acquired by the fuel remaining amount acquisition means. The work vehicle according to claim 1, wherein the fuel remaining amount acquisition means is a pressure sensor that detects the oil pressure on the bottom side of the boom cylinder as a value corresponding to the fuel remaining amount. The work vehicle according to claim 1, wherein the fuel remaining amount acquisition means is a level sensor provided in the gas cylinder and using a float for detecting the level of liquid fuel. It has mapping data in which a value corresponding to the remaining fuel amount and a command value for controlling the flow rate of working oil flowing through the boom cylinder are associated with each other.
The flow rate control means is configured to determine a command value corresponding to a value corresponding to the remaining fuel amount acquired by the fuel remaining amount acquisition means based on the mapping data, and to control using the determined command value. The work vehicle according to any one of claims 1 to 3. It has a boom direction switching valve that can switch the direction of the work oil supplied to the boom cylinder.
The flow rate control means uses a flow rate control valve that controls the flow rate of the oil passage flowing between the boom cylinder and the boom direction switching valve, and a command value according to the detection result of the fuel remaining amount acquisition means. The work vehicle according to any one of claims 1 to 4, further comprising a flow rate valve control unit that controls the flow rate control valve. A boom direction switching valve that can switch the direction of the work oil supplied to the boom cylinder, and a boom remote control valve that can switch the direction of the pilot oil supplied to the boom direction switching valve according to the operation. Have,
The flow rate control means uses a pressure reducing valve that controls the pressure of pilot oil from the boom remote control valve to the boom direction switching valve, and a command value according to the detection result of the fuel remaining amount acquisition means. The work vehicle according to any one of claims 1 to 4, further comprising a pressure reducing valve control unit for controlling the valve.

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