JP2009284712A - Body bending vehicle for industrial use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle for industrial use which can pivot turn even if a stop torque acts on the wheels for traveling. <P>SOLUTION: The wheel loader is provided such that a front side body portion 2a with right and left wheels 3 which are rotated by a motor 7, and a rear side body portion 2b with right and left wheels 4 which are rotated by a motor are bendably coupled. The wheel loader is equipped with: a stop torque providing section 21 which is inputted with the rotating speed of each wheel detected by a rotation detector 9 that can detect the rotating speed with a rotation direction of each wheel taken into consideration and which generates a stop torque which makes the rotating speed of each wheel nearly zero; and a stop torque keeping section 22 which includes an adding section 23 for calculating a sum of rotating speeds of wheels detected by the respective rotation detectors and a pivot turn determining section 24 that is inputted with the sum of rotating speeds calculated by the adding section 23, determines whether the movement of the vehicle is a pivot turn depending on whether the sum of rotating speeds is nearly zero, and outputs a command to keep the stop torque being provided to the stop torque providing section when the movement of the vehicle is found to be a pivot turn. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle body bending type industrial vehicle such as a wheel loader having a vehicle body in which a front vehicle body portion and a rear vehicle body portion are coupled so as to be able to bend each other.

Among industrial vehicles, there is a wheel loader that can be bent.
Recently, a power source has been used as a drive source for a wheel loader, and each traveling wheel provided at four positions on the left and right sides of the vehicle body is driven by an electric motor.

  By the way, such a wheel loader is large and difficult to drive. For example, in order to easily start a slope, a torque is generated in a direction opposite to the direction in which the vehicle body is lowered, that is, a stop torque is generated. Can be considered.

For example, as a specific configuration, a rotation state such as a rotation direction and a rotation speed of a traveling wheel is detected, and torque is applied to the traveling wheel so that the rotation speed is zero in a direction opposite to the rotation direction. There is what is made to act (for example, refer to patent documents 1).
JP 2002-58101 A

  As described above, when starting on a hill, stop torque is generated so that the rotation speed is zero in the direction opposite to the rotation direction. You may want to do

  By the way, when the turn is performed on the spot, for example, the left traveling wheel and the right traveling wheel have different rotational speeds (rotational speeds including the rotational direction), so that the current stop torque further increases. Therefore, there arises a problem that it is impossible to turn on the spot.

  Accordingly, an object of the present invention is to provide a vehicle body bending type industrial vehicle capable of turning on the spot even when a stop torque is applied to a traveling wheel.

In order to solve the above problems, the vehicle body bending type industrial vehicle of the present invention has a front body part having left and right traveling wheels respectively rotated by an electric motor, and a rear body wheel having left and right traveling wheels respectively rotated by an electric motor. The vehicle body is connected to the side vehicle body so as to be swingable in a horizontal plane, and is converted by a bending cylinder device attached over both vehicle body parts,
Rotation detection means capable of detecting the number of rotations in consideration of the rotation direction of each traveling wheel;
Rotation commands that take the rotation direction of each traveling wheel detected by each of these rotation detection means into account are input, and a rotation command is output to each motor so that the respective rotation number becomes substantially zero, thereby generating a stop torque. A stop torque applying portion that can be made;
An adder for obtaining the total value of the rotational speeds in consideration of the rotation direction of each traveling wheel detected by each of the rotation detecting means, and the total value obtained by the adder are input, and the total value is substantially zero. A turn determination unit for comparing whether or not there is a turn on the spot, and when the turn determination unit determines that the turn is on the spot, the stop torque applying unit And a stop torque maintaining unit capable of outputting a torque maintenance command for maintaining the stop torque as it is to the stop torque applying unit.

  According to the above configuration, when the vehicle body is converted by the stop torque applying unit in a state where the stop torque is applied to each travel wheel, the rotation speed of each travel wheel is added, and this total is added. When the value is substantially zero, it is determined that the vehicle is turning on the spot, and the current stop torque is maintained, so that the conversion can be performed even when starting on a slope.

Hereinafter, a vehicle body bending type industrial vehicle according to an embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, as an industrial vehicle, for example, a large wheel loader capable of excavating and transporting sand and the like will be described, and further, a case where the vehicle body is a bending type and an electric driving type will be described.

  As shown in FIGS. 1 and 2, the vehicle body 2 of the wheel loader 1 includes a front vehicle body portion 2a provided with front-side traveling wheels (hereinafter referred to as front wheels) 3 on the left and right sides, and a rear-side traveling device on the left and right sides. The vehicle body 2b is provided with a wheel 4 (hereinafter referred to as a rear wheel), and the vehicle body 2a and the vehicle body 2b are swung in a horizontal plane by connecting pins 5 in the vertical direction. Bendable in any direction by left and right bending hydraulic cylinders (also referred to as diverting hydraulic cylinders) 6 that are connected so as to be able to bend, and that are attached to the front body portion 2a and the rear body portion 2b. So that it can be converted. Each of the wheels 3 and 4 is driven by an electric motor 7, and therefore an inverter (also referred to as a rotational speed controller) 8 for controlling the rotational speed of each electric motor 7 is provided. Further, when the vehicle travel control is performed, the rotational speed in consideration of the rotational direction of each wheel 3, 4 is required, so the rotational direction and rotational speed of each wheel 3, 4 (the rotational speed per hour is A rotation detector (for example, an encoder is used) 9 that can detect a speed) is provided. The rotation detector 9 may be provided on the electric motor 7 side.

The front vehicle body portion 2a is mainly provided with a cargo handling device 13 including a boom 11, a bucket 12, and the like, and the rear vehicle body portion 2b is mainly provided with a power source.
The power source is composed of an engine 13, a generator 14 driven by the engine 13, and a hydraulic pump 15. Further, as a control system of the wheel loader 1, a power source from a traveling operation device 16 provided in a driver's seat is provided. A vehicle-side control unit (also referred to as a vehicle controller) 17 that inputs a travel command and outputs a rotation command to the inverter 8 of each electric motor 7 is provided.

  Of course, although not shown in the figure, the hydraulic pressure from the hydraulic pump 15 is supplied to the control device by being supplied to the working hydraulic cylinder 6 and the bending hydraulic cylinder 6 for driving the boom 11 and the bucket 12 and provided in the driver's seat. In addition, an operation control unit that controls each of the hydraulic cylinders by inputting an operation command from a work operation device such as an operation lever or a handle is provided.

  By the way, in this wheel loader 1, in order to be able to easily perform the start operation when starting on a slope, the stop load of the stop torque is provided together with a stop torque applying function that can be stopped without applying a brake when the vehicle is stopped. When turning in a state stopped by the applying function, that is, when turning on the spot, a torque maintaining function is incorporated so as to maintain the current stop torque, that is, not increase the current stop torque.

The control part having this control function will be described below.
As described above, the control device provided in the wheel loader 1 includes the vehicle-side control unit 17 that controls the traveling device and the work-side control unit that controls the work device. Since the gist of the present invention lies in the stop torque applying function and the torque maintaining function described above, here, the vehicle-side control unit 17 having these functions will be described, and among them, the stop torque is applied and the stop torque is maintained. Focus on the explanation.

  That is, as shown in FIG. 3, the vehicle-side controller 17 receives a vehicle neutral signal or a slope start mode signal from the travel operation device 16, and the rotation direction detected by each rotation detector 9. And a stop torque applying unit 21 for applying a reverse torque, that is, a stop torque so that the wheels 3 and 4 do not rotate, and a rotation direction detected by each rotation detector 9 and When the rotational speed is input to determine whether or not the vehicle is turning on the spot, the current torque maintenance command for maintaining the current stop torque is output to the stop torque applying unit 21 when it is determined that the vehicle is turning on the spot. And a stop torque maintaining unit 22 for performing the operation.

  The stop torque applying unit 21 receives the rotation number from the rotation detector 9 in consideration of the rotation direction, and sets the rotation number in the reverse direction so that the rotation number of each of the wheels 3 and 4 becomes substantially zero, that is, the stop torque. Is provided to each of the inverters 8 according to the respective wheels 3 and 4, and the stop torque applying unit 21 maintains the current torque output from the stop torque maintaining unit 22 described later. When a command is input, a torque maintaining function (also referred to as a torque limiting function) for maintaining the current stop torque so as not to increase is provided.

  In addition, the stop torque maintaining unit 22 receives the rotation number from the rotation detector 9 in consideration of the rotation direction and adds the rotation number of each wheel 5. The total value is compared with a predetermined set value, that is, a range that is substantially zero (for example, less than 1/100 of a revolution, of course, zero itself is included). There is provided a turn determination unit 42 that determines that there is a turn and outputs that fact when it is not substantially zero, and determines that the turn is not on the spot and outputs that fact.

By the way, the reason why it can be determined that the vehicle turns on the spot when the total value of the wheels 3 and 4 is substantially zero will be described.
That is, when the vehicle is turned on the spot, the front and rear vehicle body portions 2a and 2b swing around the connecting pin 5 at the same angle. In other words, in each vehicle body portion 2a and 2b, This is because the left and right wheels 3 and 4 rotate with substantially the same amount of rotation in the opposite directions, and the amount of rotation of both wheels in the front and rear becomes equal than the amount of rotation of both wheels on the left and right. is there.

In the above configuration, when the wheel loader 1 stops on a slope and starts, the slope start mode is selected.
When this hill start mode is selected, the fact is input from the traveling operation device 16 to the stop torque applying unit 21, the function of the torque generating unit 31 corresponding to each of the wheels 3 and 4 operates, and the brake is released. Even in this case, the stop torque is generated so as not to decrease, that is, not to back. For example, when the brake is released, at the moment, the vehicle body 2 is backed and the wheels 3 and 4 are rotated rearward. However, the rotational speed in consideration of the rotational direction detected by the rotation detector 9 (hereinafter referred to as this rotation). The rotational speed considering the direction is simply referred to as the rotational speed) and is input to each torque generator 31, and a rotation command for rotating the wheels 3 and 4 at a rotational speed opposite to the rotational speed is supplied to the electric motor. 7, that is, output to the inverter 8.

For this reason, although the vehicle body 2 is back for a moment, a rotation command for causing the electric motor 7 to move forward is immediately output, so that the vehicle is stopped. Therefore, it is possible to easily start on a slope.
On the other hand, as shown in FIG. 4A, when the vehicle body 2 is straight and the stop torque is applied, the steering wheel is turned in a predetermined direction, for example, the right direction in order to turn, that is, turn in place. As shown in FIG. 4 (b), the front vehicle body portion 2 a and the rear vehicle body portion 2 b are bent into a “<” shape by the bending hydraulic cylinder 6.

  When bent in this way, for example, the left wheel 3 (3L) on the front side rotates forward and the right wheel 3 (3R) rotates rearward, for example, rotating at substantially the same rotational speed in opposite directions. . The same can be said for the rear side. That is, the rear left wheel 4 (4L) rotates rearward and the right wheel 4 (4R) rotates forward.

  Therefore, if the number of rotations of all the wheels 3 and 4 is added in the adding unit 41, the total value becomes substantially zero, so this total value is input to the turning determination unit 42, and a predetermined set value, that is, substantially zero. It is determined whether or not.

  When it is determined that the torque is substantially zero, that is, when it is determined that the vehicle is turning on the spot, a current torque maintenance command for maintaining the current torque is output to each torque generation unit 31 of the stop torque applying unit 21, The currently generated stop torque is maintained.

That is, even when the vehicle starts on a hill or when the vehicle turns on the spot, the current stop torque is not increased, so that conversion can be easily performed.
When the total value is not substantially zero, the torque maintenance signal is not output to the stop torque applying unit 21, and the stop torque function is continued.

  As described above, when the vehicle body 2 is turned in a state where the stop torque is applied to the wheels 3 and 4 by the stop torque applying unit 21, the rotation direction of the wheels 3 and 4 is taken into consideration. When the total number of rotations is added to approximately zero, it is determined that the vehicle is turning on the spot, and the current stop torque is maintained and is not increased. Field turning can be performed easily.

It is a top view which shows schematic structure of the vehicle body bending type industrial vehicle which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of the traveling part of the industrial vehicle. It is a block diagram which shows schematic structure of the control part in the industrial vehicle. It is a schematic plan view which shows the turning state of the vehicle body in the industrial vehicle, (a) shows the time of going straight, and (b) shows the time of bending.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel loader 2 Car body 2a Front side car body part 2b Rear side car body part 3 Front side traveling wheel 4 Rear side traveling wheel 6 Bending hydraulic cylinder 7 Electric motor 8 Inverter 9 Rotation detector 13 Cargo handling device 14 Generator 15 Hydraulic pump 16 Vehicle side Control unit 21 Stop torque application unit 22 Stop torque maintenance unit 31 Torque generation unit 41 Addition unit 42 Turn determination unit

Claims (1)

A front vehicle body portion having left and right traveling wheels respectively rotated by an electric motor and a rear vehicle body portion having left and right traveling wheels respectively rotated by an electric motor are swingably connected in a horizontal plane, and both An industrial vehicle in which turning is performed by a bending cylinder device attached over a vehicle body part,
Rotation detection means capable of detecting the number of rotations in consideration of the rotation direction of each traveling wheel;
Rotation commands that take the rotation direction of each traveling wheel detected by each of these rotation detection means into account are input, and a rotation command is output to each motor so that the respective rotation number becomes substantially zero, thereby generating a stop torque. A stop torque applying portion that can be made;
An adder for obtaining the total value of the rotational speeds in consideration of the rotation direction of each traveling wheel detected by each of the rotation detecting means, and the total value obtained by the adder are input, and the total value is substantially zero. A turn determination unit for comparing whether or not there is a turn on the spot, and when the turn determination unit determines that the turn is on the spot, the stop torque applying unit A vehicle body bending type industrial vehicle, comprising: a stop torque maintaining unit capable of outputting a torque maintenance command for maintaining the stop torque applied in step 1 to the stop torque applying unit.

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