JP2006218974A - Slip preventive system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slip preventive system capable of determining whether slip occurs or not, without using an expensive ground speed sensor. <P>SOLUTION: A control device 2 detects the actual number of rotations of each axle from a rotation number sensor of the axle such as a front side left axle 11a. On the other hand, the estimated number of rotations of each axle is calculated by information obtained from an engine speed sensor 6 and a transmission gear ratio sensor 7. When a rotation number difference between the actual number of rotations and the estimated number of rotations is not less than a set number of rotations, it is determined that slip occurs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for detecting slipping of a wheel of a work vehicle and controlling so as not to slip when slipping is detected.

Conventionally, there is an agricultural work vehicle that performs tillage or the like as an example of a work vehicle.
Since such an agricultural work vehicle performs work by bringing a work machine provided at the rear of the machine body into contact with the farm field, the load on the machine body is large, and thus the wheels may slip.
When slipping occurs in this way, there are problems such as a reduction in work efficiency of the work vehicle, a stop in the field, or a decrease in stability.
Therefore, conventionally, a system for preventing slippage is mounted on a work vehicle to prevent the above-described problem from occurring.
An example of such a technique is shown in Patent Document 1 below.
In Patent Document 1, when slip occurs, the clutch on the path for transmitting the driving force from the engine to the wheels is put into a half-clutch state, thereby reducing the driving force and suppressing the occurrence of slip. .
As another technique, a ground speed sensor or the like is provided on the work vehicle to detect the actual speed of the work vehicle, and when the actual speed does not reach the speed that should come out at the actual number of revolutions of the wheel or axle, it is judged as slip. There is a technology to reduce the engine speed.
JP-A-6-58345

However, in the technique as shown in Patent Document 1 described above, when slip occurs, the generation of slip is suppressed by weakening the driving force that transmits the output of the engine to the axle or the like, so energy is wasted. There is a problem that the vehicle speed drops and the finish becomes worse.
In other words, the technique disclosed in Patent Document 1 does not control the output of the engine when a slip occurs, but simply adjusts the driving force to the axle with a transmission mechanism such as a clutch. In, the engine energy is wasted, the rotational speed of power transmission to all wheels is reduced, and the rotational speed of the engine is also reduced, resulting in a torque drop. Therefore, there is a problem that the finish due to the speed change becomes worse in the tillage work or the like.
In addition, regarding the technique for determining slip using the above-described ground speed sensor, it is necessary to provide the ground speed sensor in addition to the rotational speed sensor that measures the rotational speed of the axle or the like, and the ground speed sensor is expensive. In addition, there is a problem that the manufacturing cost of the work vehicle becomes high.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  In claim 1, based on the detection value of the actual rotational speed detection means for detecting the actual rotational speed of the axle in the work vehicle that transmits the output of the engine to the wheels via the transmission, the differential gear, and the axle. In the anti-slip system for preventing slipping of the wheel, the estimated rotational speed of the axle calculated from the rotational speed of the engine and the transmission gear ratio, and the actual speed of the axle detected by the actual rotational speed detection means. A first slip determination means for determining that a slip has occurred when the difference in rotational speed from the rotational speed is equal to or greater than a predetermined rotational speed is provided.

  In claim 2, based on a detection value of an actual rotation speed detecting means for detecting an actual rotation speed of the axle in a work vehicle that transmits the output of the engine to the wheels via a transmission, a differential gear, and an axle. In the anti-slip system for preventing the wheel from slipping, when the rotational speed difference between the axles exceeds a predetermined number of times based on the detection value of the actual rotational speed detection means, or the actual rotational speed Based on the detection value of the number detection means, it is determined that a slip has occurred when the rotational speed difference between the rotational speed of one of the axles and the average rotational speed of each axle is equal to or greater than a preset rotational speed. Second slip judging means is provided.

  According to a third aspect of the present invention, when it is determined that slip has occurred, the axle having the fastest rotational speed is controlled to decelerate to the estimated rotational speed or the average rotational speed.

  According to a fourth aspect of the present invention, when an operation angle of a steering handle provided in the work vehicle is operated more than a predetermined set angle, it is not determined whether or not slip occurs, and on the other hand, an operation angle of the steering handle is not determined. However, if it is within the range of the predetermined set angle, it is determined whether or not slip has occurred.

  As effects of the present invention, the following effects can be obtained.

  According to the configuration of the first aspect, it is possible to determine the presence or absence of slip without using an expensive ground speed sensor or the like, so that it is possible to configure a slip prevention system at a lower cost than in the past.

  With the configuration of claim 2, the slip prevention processing is performed based on the rotational speed difference between the axles or the rotational speed difference between one of the axles and the average rotational speed. It is possible to grasp the rotational speed balance of each axle (that is, each wheel) and appropriately perform slip generation prevention processing.

  With the configuration according to the third aspect, by reducing the engine speed, it is possible to surely prevent slipping with less energy loss compared to the case of reducing the engine speed using a conventional clutch.

  According to the configuration of the fourth aspect, for example, when the steering handle is greatly operated, the work vehicle turns greatly, and the difference in the rotational speed between the axles becomes large due to the action of the differential gear, slip occurs. It is possible to prevent erroneous determination.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following best mode for carrying out the present invention is an example embodying the present invention, and is not intended to limit the technical scope of the present invention.
FIG. 1 is a schematic configuration diagram illustrating an example of a tractor 200 that employs an anti-slip system 1, FIG. 2 is a block diagram illustrating an example of a control system of the anti-slip system 1 of the present invention, and FIG. FIG. 4 is a flowchart showing an example of a series of processes performed by the control device.

<Models with anti-slip system>
First, a schematic configuration of a four-wheel tractor 200 as shown in FIG. 1 will be described as an example of a work vehicle employing the anti-slip system of the present invention.
In the following description, the direction of arrow A in FIG. 1 is the front side of the tractor 200, and the front side of the page in FIG. 1 is the left side surface of the tractor 200.
A front left wheel 12a, a front right wheel 12b, a rear left wheel 22a, and a rear right wheel 22b are provided before and after the tractor 200. (Illustrated).
An engine 31 is disposed inside the hood 30 on the front side of the machine body, and a cabin 40 is provided behind the hood 30.
In the cabin 40, a steering handle 16 is disposed in the vicinity of the dashboard 17 on the front side, and a seat 18 is disposed behind the steering handle 16. Further, a roof 41 is provided on the upper portion of the cabin 40, and a door 42 is provided on the side surface side.
A clutch housing 34 is disposed at the rear of the engine 31, a transmission 32 is disposed at the rear of the clutch housing 34, and a branch gear box 33 for branching the driving force to the front wheels and the rear wheels is provided. .
The output side of the branch gear box 33 will be described later with reference to FIG.
In addition, a rotary tiller 50 that is lifted and lowered by being connected to a hydraulic cylinder provided at the rear of the tractor 200 is connected to the rear portion of the tractor 200.

<Control device>
Next, an example of a schematic configuration of the control system when the slip prevention system 1 of the present invention is employed in the tractor 200 as described above will be described.
First, the slip prevention system 1 is provided with a control device 2 for performing storage, calculation, analysis, and control in the entire system.
The control device 2 includes a front left axle 11a, a front right axle 11b, a rear left axle 21a, and a rear right axle 21b, which are the axles of the four wheels. The front left axle rotational speed sensor 3a, the front right axle rotational speed sensor 3b, the rear left axle rotational speed sensor 4a, and the rear right axle rotational speed sensor 4b are detected. Connected with.
That is, these four sensors are an example of an actual rotational speed detecting means for detecting the actual rotational speed of each axle.
The control device 2 is connected to a fuel injection valve 5, an engine speed sensor 6, and a gear ratio detection sensor 7 that detects a gear ratio of the transmission 32.

<Differential gear>
The output of the branch gear box 33 is transmitted to the front differential gear 10 and the rear differential gear 20 through the two output shafts of the front wheel side output shaft 33c and the rear wheel side output shaft 33d.
The front differential gear 10 branches the rotational force of the front wheel output shaft 33c to the front left axle 11a and the front right axle 11b.
The rear differential gear 20 branches the rotational force of the rear wheel output shaft 33d to the rear left axle 21a and the rear right axle 21b.

<Steering angle sensor>
Further, at one end of the steering handle 16, a steering gear 16a that meshes with a steering rack 15 that steers the front wheels (the front left wheel 12a and the front right wheel 12b) is provided.
Further, a steering sensor 13 for detecting the rotation amount of the shaft is provided on the shaft connecting the steering handle 16 and the steering gear 16a. However, the steering rack 15 can be steered using a tie rod, or can be configured to steer using a hydraulic cylinder or the like, and the steering sensor 13 detects the steering angle of the front wheels. If it is.
Further, since the steering sensor 13 is connected to the control device 2, the control device 2 can recognize the operation angle of the steering handle 16 based on the detected value of the steering sensor 13.

<Judgment based on the difference between the estimated speed and the actual speed>
Here, the process which the slip prevention system 1 of this invention recognizes generation | occurrence | production of a slip is demonstrated using the flowchart of FIG.
Based on the detection values obtained from the engine speed sensor 6 and the transmission ratio detection sensor 7, the control device 2 sets each axle (that is, the front left axle 11a, the front right axle 11b, the rear left axle 21a, the rear right axle 21b). In the following, the estimated rotational speed of each “axle” is calculated, and each axle rotational speed sensor (front left axle rotational speed sensor 3a, front right axle rotational speed sensor 3b, rear left axle rotational speed) is calculated. The actual rotational speed of each axle is detected from the number sensor 4a and the rear right axle rotational speed sensor 4b (hereinafter simply referred to as “each axle rotational speed sensor”) (S10).
The control device 2 determines whether or not the difference in rotational speed between the estimated rotational speed obtained in step S10 and the actual rotational speed is equal to or greater than a preset rotational speed (S20).
If it is determined in step S20 that the rotational speed is equal to or higher than the set rotational speed, the process proceeds to step S30. If it is determined that the rotational speed is equal to or lower than the set rotational speed, the process proceeds to step S10 again.
When it is determined in step S20 that the rotation speed is equal to or higher than the set rotational speed, the control device 2 determines that slip has occurred (S30).
Theoretically, as long as the engine speed and the gear ratio are determined, other wheel diameters and other specifications do not change, so the rotational speed of each axle can be obtained as the estimated rotational speed. Since the moving gear 20 is provided, the actual rotational speed and the estimated rotational speed do not match and a slight rotational speed difference is generated.
However, when a large rotational speed difference that does not normally occur due to the specifications and characteristics of the work vehicle, the differential gear, and the like occurs, it is necessary to determine that slip has occurred.
Therefore, in step S30, the control device 2 determines that slip has occurred when the rotational speed difference is equal to or greater than the set rotational speed. Further, since it is the control device 2 that determines whether or not slip has occurred, the control device 2 is an example of slip determination means.
The set rotational speed can be obtained in advance and stored in the control device 2 as the maximum rotational speed difference allowable from the specifications and characteristics of the work vehicle and the differential gear in the development stage of the work vehicle. This rotational speed difference is set larger as the speed increases.
And since it was judged that the slip has generate | occur | produced in the said step S30, the control apparatus 2 performs the process which prevents generation | occurrence | production of a slip (S40).
Since the presence / absence of slip is determined in this way, it is possible to determine the presence / absence of slip without using an expensive ground speed sensor or the like, so that a slip prevention system is configured at a lower cost than in the past. It becomes possible.

<Rotational speed difference between axles>
A determination process different from the above will be described.
First, the control device 2 detects the actual rotational speed of each axle from each axle rotational speed sensor, and calculates the rotational speed difference between the detected axles (S11).
And the control apparatus 2 judges whether the rotation speed difference calculated by step S11 is more than the preset setting rotation speed (S21).
If it is determined in step S21 that the rotational speed is equal to or higher than the set rotational speed, the process proceeds to step S31. If it is determined that the rotational speed is equal to or lower than the set rotational speed, the process proceeds to step S11 again.
When it is determined in step S21 that the rotation speed is equal to or higher than the set rotational speed, the control device 2 determines that slip has occurred (S31).
That is, when a large rotational speed difference that does not normally occur due to the specifications and characteristics of the work vehicle, the differential gear, etc. occurs between the axles, it is determined that slip has occurred.
And since it was judged that the slip has generate | occur | produced in the said step S31, the control apparatus 2 performs the process which prevents generation | occurrence | production of a slip (S41).

<Difference between any axle and average speed of each axle>
You may perform the process of the said step S11 and step S21 as follows.
In step S11 described above, the control device 2 detects the rotational speed of each axle and calculates an average value thereof.
In step S21 described above, the control device 2 determines whether or not the difference in rotational speed between the rotational speed of any axle and the average rotational speed is greater than or equal to a predetermined set rotational speed.
In other words, if a large number of rotations that does not normally occur due to the specifications and characteristics of the work vehicle, differential gear, etc. occurs relative to the average rotation number of each axle, it is determined that slip has occurred. To do.
If it is determined by this determination that the rotation speed is equal to or higher than the set rotational speed, the control device 2 performs a process for preventing the occurrence of slip as in step S41 described above.
As described above, since the slip prevention processing is performed based on the rotational speed difference between the axles, or the rotational speed difference between any of the axles and the average rotational speed, the control device 2 can control each axle. In other words, it is possible to grasp the rotation number balance of each wheel and appropriately perform the slip generation prevention process.

<Deceleration control>
A process for preventing the occurrence of slip in the above step S40, step S41 and the like will be described.
For example, the control device 2 performs a process of controlling the rotational speed of the engine 31 so as to decelerate the axle having the fastest rotational speed to the estimated rotational speed or the average rotational speed of each axle.
In this case, the control device 2 shifts the transmission to the low speed side while maintaining the rotational speed of the engine 31 substantially. In other words, a process is performed in which the speed change lever is increased and the speed change lever or the like is operated by an actuator such as a motor or a cylinder so that the rotation of the axle having the highest rotational speed is reduced.
By decelerating in this way, it is possible to reliably prevent slipping with less energy loss compared to the case where the rotational speed is decelerated using a conventional clutch.
In addition, when a work machine is mounted on the machine, the work machine is raised to the set height instead of or in addition to the control for reducing the speed in the process for preventing the slip. It is also possible to control it.

<Operation angle>
It is also possible to determine whether or not to perform a series of processes for determining whether or not slip has occurred as shown in steps S10 to S40 or steps S11 to S41 based on the operation angle of the steering wheel. It is.
In this case, for example, when the operation angle of the steering wheel that can be acquired from the steering sensor 13 is equal to or larger than a predetermined set angle, the control device 2 does not determine whether or not slip has occurred, and on the other hand, the set angle If it is within the range, a process for determining whether or not slip has occurred is performed. In other words, if it is a straight-ahead state, it is being worked, so it is detected whether or not it has slipped, and when turning, it is a state in which no work is being performed, and a difference in rotational speed occurs, so slip determination is not performed It is.
By performing such processing, work efficiency is not lowered in the following situations.
For example, when turning at the field end, the steering handle 16 is largely operated, and the difference in the rotational speed between the left and right wheels is increased by the action of the front differential gear 10 and the rear differential gear 20 described above. It cannot be determined whether slip has occurred.
That is, in such a case, the control device 2 erroneously determines that a slip has occurred, so that the operation angle of the steering handle 16 is larger than the set angle as described above. When the operation is performed, it is possible to prevent the above-described work efficiency from being lowered by not performing the process of determining the presence or absence of slip.

The schematic block diagram which showed an example of the tractor 200 which employ | adopts the slip prevention system 1. FIG. The block diagram which showed an example of the control system of the slip prevention system 1 of this invention. The flowchart which showed an example of the series of processes which a control apparatus performs. The flowchart which showed an example of the series of processes which a control apparatus performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slip prevention system 2 Control apparatus 3a Front left axle rotational speed sensor 3b Front right axle rotational speed sensor 4a Rear left axle rotational speed sensor 4b Rear right axle rotational speed sensor 6 Engine rotational speed sensor 7 Gear ratio detection sensor 13 Steering ratio Sensor 50 Rotary tiller 200 Tractor

Claims (4)

Prevents slipping of the wheel based on the detection value of the actual rotation speed detecting means for detecting the actual rotation speed of the axle in the work vehicle that transmits the engine output to the wheel via the transmission, the differential gear, and the axle. In the slip prevention system that
The difference in rotational speed between the estimated rotational speed of the axle calculated from the rotational speed of the engine and the transmission gear ratio, and the actual rotational speed of the axle detected by the actual rotational speed detection means,
A slip prevention system comprising first slip judgment means for judging that a slip has occurred when the rotational speed is equal to or higher than a predetermined rotational speed. Prevents slipping of the wheel based on the detection value of the actual rotation speed detecting means for detecting the actual rotation speed of the axle in the work vehicle that transmits the engine output to the wheel via the transmission, the differential gear, and the axle. In the slip prevention system that
Based on the detection value of the actual rotational speed detection means, when the rotational speed difference of each axle is equal to or greater than a predetermined number of times,
Or
Based on the detection value of the actual rotational speed detection means, when the rotational speed difference between the rotational speed of any axle and the average rotational speed of each axle is equal to or greater than a preset rotational speed,
A slip prevention system comprising second slip judgment means for judging that slip has occurred. If it is determined that a slip has occurred,
The anti-slip system according to claim 1 or 2, wherein the axle having the fastest rotational speed is controlled to decelerate to the estimated rotational speed or the average rotational speed. When an operation angle of a steering wheel provided in the work vehicle is operated more than a predetermined set angle, it is not determined whether slip has occurred,
On the other hand
The slip prevention system according to any one of claims 1 to 3, wherein when the operation angle of the steering wheel is within a predetermined set angle range, it is determined whether or not slip occurs.

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