JPH11118030A - Transmission control method and control device for wheel crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a wheel crane safely run on the long slope way of a general public road while applying brake and by making other automobiles running in front and back of itself follow. SOLUTION: A control section is added to the controller 22 of a transmission control device 20 for controlling the transmission 3 of a wheel crane provided with a retarder 7 for automatically shifting down the transmission 3 when the running speed of the wheel crane becomes lower than the specified speed prescribed beforehand due to the stepping of a brake pedal while the actual cooling water temperature detected by a water temperature sensor 24 is higher than the specified temperature prescribed beforehand when the actual cooling water temperature of the cooling water after cooling retarder oil is detected by the water temperature sensor 24. In this constitution, retarder oil is effectively cooled due to an increase in cooling water because of an increase in the speed of an engine 1, resulting in the prevention of the retarder 7 from down regulation. Therefore, the wheel crane can run safely followed by other automobiles in front and back of the crane itself on the long slope way of a general public road while applying a brake.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the technical field of a transmission control method for a wheel crane and a transmission control device for a wheel crane.

[0002]

2. Description of the Related Art In a vehicle having a large gross vehicle weight such as a large vehicle and a vehicle for construction equipment, the speed energy becomes extremely large when descending on a slope or when the vehicle speed is high.
With only a main brake device such as a drum brake or a disc brake for braking the running wheels, the braking force gradually decreases as the temperature rises due to continuous braking. To compensate for this, auxiliary brakes such as an exhaust brake and a retarder are provided. Hereinafter, the configuration of a typical vehicle according to Conventional Example 1 having such an auxiliary brake will be described with reference to FIG. 5 which is a schematic plan view thereof.

[0003] The driving force of the engine 1 is transmitted to tires 5 and 5 as running wheels through a torque converter 2, a transmission 3, a hydraulic retarder 7 as an auxiliary brake, and an axle 4, so that the vehicle can run. ing. In the transmission device 20, when traveling on a flat road, downhill road, uphill road, or the like, the speed stage of the transmission 3 automatically changes according to the traveling speed, the engine speed, and the amount of depression of the accelerator pedal. Automatic control (hereinafter referred to as normal automatic shift program control) of a drive system (engine, torque converter, transmission, etc.) that shifts without shock is performed. Further, when the vehicle is decelerating or going down a slope, the tires 5 and 5 are braked by the main brake device, and the power transmitted from the tires 5 and 5 is absorbed by the engine 1 and the retarder 7. . The braking force of the retarder 7 is controlled by the retarder control device 10.
Is operated by operating the control lever 11a of the retarder control lever device 11 which constitutes the above. The retarder control valve 13 is controlled in accordance with the operation angle.

Since such a retarder 7 is configured to convert kinetic energy into heat by circulating the retarder oil, an oil cooler 7a built in the retarder 7
In order to cool the retarder oil by circulating cooling water after cooling the engine, the oil cooler 7a and the engine 1
Are communicated with each other via a cooling water circulation pipe 6 including a cooling water supply pipe 6a and a cooling water return pipe 6b. And
The actual cooling water temperature of the cooling water after the retarder oil cooling detected by the retarder control water temperature sensor 14 provided in the cooling water return pipe 6b constituting the cooling water circulation pipe 6 is a predetermined temperature (for example, When the temperature exceeds 96 ° C.), a control of reducing the braking force of the retarder 7 (hereinafter, referred to as down regulation) is performed to protect the engine 1, the retarder 7, and other cooling systems. Reference numeral 8 provided on the exhaust pipe of the engine 1 is an exhaust brake, and reference numeral 20 is
It is a transmission control device.

By the way, when descending on a slope, the retarder is naturally actuated (if the braking is performed only by the main brake device, heating of the main brake device → generation of vapor lock, fade, etc. → reduction of the braking force of the main brake device). For)
The vehicle is braked, but when the vehicle climbs a steep hill, a large amount of power is required, so immediately after climbing, the temperature of the engine cooling water is inevitably high. If the braking force of the retarder is increased, the amount of heat generated will increase and the temperature of the cooling water will increase further.In addition, if the torque converter lock-up clutch is disengaged due to a decrease in speed, the torque converter will enter the torque converter state. The engine speed drops to the idling state, the engine cooling water volume decreases, and the cooling water becomes hotter,
Eventually, the retarder is down-regulated, which makes it impossible to brake downhill with the retarder, which may lead to a very dangerous situation. At this time, the driver operates the main brake device by depressing the brake pedal in order to drive safely on a slope while braking. Raise the control stage to increase the retarder braking force. Shift down the transmission gear. The above-mentioned danger can be avoided by performing such operations instantaneously.

[0006] However, once the driver enters a dangerous state as described above, the driver may panic and may not be able to take appropriate measures. By the way, the above-mentioned problem is prevented by automatically controlling the retarder to avoid down regulation of the retarder. For example, Japanese Patent Publication No. 63-12827 (Conventional Example 2) JP-B-2-19023 (Conventional example 3) or JP-A-8-19023
No. 26093 (Conventional Example 4)
Hereinafter, these outlines will be sequentially described.

[0007] An automatic retarder brake (hereinafter referred to as "retarder") automatic control device according to Conventional Example 2 disclosed in Japanese Patent Publication No. 63-12827 is applied to a dump truck that reciprocates a predetermined distance. A vehicle speed setting device for setting a command vehicle speed, a detector for detecting an actual vehicle speed, a gear position of a transmission, and a brake cooling oil temperature; When the brake cooling oil temperature exceeds a predetermined value by using the output of the engine as an input, the gear position is shifted, and the provisional command vehicle speed is calculated from the running curve to reduce the speed below the command vehicle speed and increase the engine speed. A control device that outputs a brake signal, and a converter that converts the brake signal into a corresponding braking force and applies the same to a dump truck,
When the brake cooling oil temperature rises, the engine rotation speed is increased to increase the brake cooling oil amount and lower the cooling oil temperature.

Therefore, according to the automatic retarder control apparatus according to the conventional example 2, the command vehicle speed signal, the actual vehicle speed signal, the gear position signal, and the brake cooling oil temperature signal output from the vehicle speed setting device and the respective detectors are provided by the microcomputer. Once read into compares the command vehicle speed V _s and the actual vehicle speed V, when the actual vehicle speed V is higher than the command vehicle speed V _s is output braking signal is judged that it is necessary to lower the vehicle speed, brake The car speed is reduced by being applied. Next, the brake cooling oil temperature T is compared with the preset oil temperature T _1, and when T is less than T _1, V _s = V
The brake is applied until, T is above T ₁ tentative specified vehicle speed V _S of the vehicle speed and outputs a brake signal when '
Down, shift down the gear by one step, and change V _S ′ to V
_The vehicle is driven for a predetermined time at V _S ′ by calculating from the running curve so that the engine speed is as high as possible and the engine speed is as high as possible. In this way, the engine rotation speed is increased to increase the amount of brake cooling oil, and the temperature of the cooling oil is lowered to maintain the braking function. Then, this brake cooling oil temperature T even if the is higher than the preset oil temperature T ₁ are those further so as to further stage downshift.

The automatic retarder control device according to the prior art 3 disclosed in Japanese Patent Publication No. 2-19023 is also applied to a dump truck that reciprocates a predetermined distance, and shifts down according to a decrease in vehicle speed. In a retarder automatic control device for a vehicle equipped with an automatic transmission and a retarder that is oil-cooled by a cooling oil having a flow rate corresponding to a rotation speed of an engine, a vehicle speed setting means for setting a target speed of the vehicle, and a cooling oil for the retarder. A temperature sensor for detecting the temperature, a vehicle speed sensor for detecting the actual vehicle speed of the vehicle, and a cooling oil temperature in order from a low temperature side to a high temperature side in an oil temperature stable area, an oil temperature caution area, and an oil temperature danger area. It is classified into at least three regions, and it is determined which of the three regions the cooling oil temperature detected by the temperature sensor belongs to, and it is determined that the detected cooling oil temperature belongs to the oil temperature stable region. Output, a retarder control signal corresponding to the deviation between the target speed and the actual vehicle speed set by the vehicle speed setting means is output.If it is determined that the detected cooling oil temperature belongs to the oil temperature caution area, In the automatic transmission, the retarder control signal is increased until the currently selected gear shifts down, and after the shift down is performed, the actual vehicle speed at the time of the shift down is set as the temporary setting vehicle speed,
A retarder that outputs a retarder control signal according to the deviation between the provisional vehicle speed and the actual vehicle speed, and outputs a retarder control signal that stops the vehicle if the detected cooling oil temperature is determined to belong to the oil temperature danger area. It comprises a control device and retarder driving means for driving the retarder according to each retarder control signal output from the retarder control device.

According to such a retarder automatic control device, an oil temperature caution area is set between an oil temperature danger area and an oil temperature safety area, and when the cooling oil temperature enters the oil temperature caution area, the engine is shifted down to shift the engine. The temperature of the cooling oil of the retarder is decreased by increasing the rotation speed to increase the amount of the cooling oil. Further, the vehicle speed at the time of downshifting is set as a tentative set vehicle speed, and a retarder control signal corresponding to a deviation between the tentative set vehicle speed and the actual vehicle speed is output to prevent the vehicle speed from increasing. It is.

A braking force control method according to a fourth conventional example disclosed in Japanese Patent Application Laid-Open No. Hei 8-26093 will be described. A braking device control unit for controlling the operation state of each auxiliary braking device includes a retarder using a temperature detection sensor. Monitor the temperature.When the retarder temperature is lower than the reference value, operate the retarder with the highest priority.When the retarder temperature is higher than the reference value, operate the auxiliary braking device other than the retarder with the highest priority, according to the traveling state. This is to obtain a braking force. The auxiliary braking devices in the braking force control method according to Conventional Example 4 are an exhaust brake device and a third valve type engine brake auxiliary system.

[0012]

All of the prior arts 2 to 4 are superior to the prior art 1 in that the retarder down regulation can be automatically avoided and the vehicle can be reliably braked. However, each has the following issues to be solved. First,
The automatic retarder control devices according to Conventional Examples 2 and 3 are applied to a dump truck used for ore transportation in a mine or the like, and when traveling downhill, the retarder automatic control device sets the command vehicle speed set by the retarder using a command vehicle speed setting device. Therefore, if such a technology is applied to a wheel crane traveling on a general public road, which must travel while paying attention to the trends of various vehicles before and after, various speed changes cannot be handled. , Cannot be applied to wheel crane.

Further, in the braking force control method according to Conventional Example 4, the third valve type engine brake auxiliary system is used for an auxiliary braking device other than the retarder that is preferentially operated when the retarder temperature is higher than the reference value. I have. Such a third valve type engine brake assist system is not provided for a general engine, and thus cannot be applied to a vehicle equipped with a general engine. Of course, it is sufficient to use an engine having a third valve type engine brake assist system, but it is expensive because the engine has special specifications, which is not preferable from an economic viewpoint.

Therefore, an object of the present invention is to apply the invention to a wheel crane equipped with a general engine, to always exert a stable braking force, and to quickly perform even if the retarder is in a down-regulation state. An object of the present invention is to provide a transmission control method of a wheel crane and a control device therefor, which make it possible to return to a state where a normal braking force can be exerted.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in order to solve the above-mentioned problems, a transmission control method for a wheel crane according to claim 1 of the present invention has been adopted. The means detects the temperature of the cooling water after cooling the retarder oil supplied from the engine side, compares the detected actual cooling water temperature with a predetermined predetermined temperature, and determines the actual cooling water temperature. When the temperature exceeds the predetermined temperature, the transmission automatically shifts down when the wheel crane becomes lower than the predetermined speed or lower than the predetermined engine speed by depressing the brake pedal that operates the main brake device, while the actual cooling water is When the temperature is equal to or lower than a predetermined temperature, the transmission speed stage is controlled based on normal automatic shift control. .

According to a second aspect of the present invention, there is provided a transmission control method for a wheel crane according to the first aspect, wherein the transmission is controlled by depressing an accelerator pedal. It is characterized by returning to normal automatic shift control.

According to a third aspect of the present invention, there is provided a wheel crane transmission control device including a brake pedal for operating a main brake device for braking a traveling wheel, wherein a braking force is controlled by a retarder control device. Transmission control of a wheel crane for controlling the transmission of a wheel crane provided with a fluid type retarder having an oil cooler for cooling a retarder oil by cooling water after cooling an engine which is a driving source of the traveling wheel In the device,
The transmission control device compares the actual cooling water temperature of the cooling water after cooling the retarder oil returned to the engine side from the oil cooler with a predetermined temperature, and the actual cooling water temperature exceeds the predetermined temperature. When the wheel crane falls below a predetermined speed or below a predetermined engine speed due to depression of a brake pedal, a control unit for automatically shifting down the transmission is added.

According to a fourth aspect of the present invention, in the transmission control apparatus for a wheel crane according to the third aspect, the transmission control apparatus for a wheel crane according to the third aspect is configured such that the transmission control apparatus is operated by depressing an accelerator pedal. An automatic return control unit for returning to normal automatic shift control is added.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A transmission control device according to an embodiment for carrying out a wheel crane transmission control method according to the present invention will be described below with reference to FIG. When,
2 to 4 of a flowchart for explaining the operation of transmission control by the transmission control device shown in FIG. 1, the same components as those of the conventional example 1 and those having the same functions are denoted by the same reference numerals. It will be described using FIG.

First, the arrangement of the main components of the wheel crane will be described with reference to FIG. 1. Reference numeral 1 shown in FIG. 1 denotes a radiator 1a and a water jacket 1b.
And a diesel engine having: This engine 1
A torque converter 2, a transmission 3 whose speed stage is automatically shifted by a transmission control device 20 described later, a hydraulic retarder 7 as an auxiliary brake whose braking force is controlled by a retarder control device 10 described below, The power is transmitted to tires 5 and 5 as running wheels via an axle (axle) 4. Further, an exhaust brake 8 which is an auxiliary brake other than the retarder 7 is provided in the exhaust manifold 1c of the engine 1. In addition,
In this embodiment, the retarder 7 is provided between the transmission 3 and the axle 4. However, even if the retarder is provided between the engine 1 and the torque converter 2, 3 may be provided.

The retarder 7 is provided with an oil cooler 7a that absorbs kinetic energy for braking the wheel crane and cools the hot retarder oil. In order to cool the retarder oil, the oil cooler 7a and the engine 1 are connected to a cooling water supply line 6a communicating with the water jacket 1b and the oil cooler 7a.
And a cooling water return line 6b communicating with the radiator 1a. Accordingly, the cooling water cooled by the radiator 1a flows into the water jacket 1b to cool the engine 1, and then flows into the oil cooler 7a through the cooling water supply line 6a to cool the retarder oil of the retarder 7 and Then, the cooling water is returned to the radiator 1a through the cooling water return pipe 6b, cooled, and the engine 1 and the retarder oil are cooled again.

Next, a retarder control device 10 for controlling the braking force of the retarder 7 is disposed near the retarder control lever device 11 having a control lever 11a and the coolant outlet of the coolant return line 6b. The retarder controller 12 includes a retarder controller 12 to which the water temperature detected by the retarder control water temperature sensor 14 for detecting the temperature of the cooling water after cooling the retarder oil is inputted, and a retarder control valve 13. In other words, the shift lever 11a of the retarder control lever device 11 is operated, and the braking force of the retarder 7 is controlled by the retarder control valve 13 controlled according to the operation angle.

Of course, like the retarder according to the conventional example, the retarder 7 is provided when the actual cooling water temperature detected by the retarder control water temperature sensor 14 exceeds a predetermined temperature (for example, 96 ° C.). , Engine 1, this retarder 7
It is configured to be down-regulated by the retarder controller 12 to protect other cooling systems. Reference numeral 15 denotes a compressed air supply source for supplying compressed air to the retarder control valve 13 that controls the braking force of the retarder 7 by changing the air pressure.

A transmission control device 20 for controlling the speed position of the transmission 3 outputs a shift lever device 21 having a shift lever 21a for selecting an operation position of a speed position, which will be described later, and a control signal for shifting the speed position of the transmission 3. Controller 22
And The controller 22 has a water temperature sensor 24 disposed near the cooling water outlet of the cooling water return pipe 6b and downstream of the retarder control water temperature sensor 14 to detect the temperature of the cooling water. The detected actual coolant temperature is input, the traveling speed of the wheel crane detected by the vehicle speed sensor 25 that detects the rotation speed of the output shaft of the transmission 3 is input, and the rotation of the tires 5 and 5 is braked. A depression signal is input from a brake depression detection sensor that detects depression of a brake pedal (not shown) for operating the brake device.

A speed stage position signal to which a signal from an accelerator depression sensor for detecting the depression amount of an accelerator pedal 9 for the operator to adjust the fuel supply amount to the engine 1 is input, as well as the traveling speed and the engine speed. The drive system (engine, torque converter, transmission, etc.) is provided with the same control unit as in the first conventional example in which the drive system (engine, torque converter, transmission, etc.) is controlled by a normal automatic speed change program so as to shift without a shock according to the number and the depression amount of the accelerator pedal 9. . In addition,
In the transmission control device according to this embodiment, as described above, the actual cooling water temperature detected by the separately provided water temperature sensor 24 is input, but is detected by the retarder control water temperature sensor 14. It is possible to use the actual cooling water temperature, and the arrangement position is not limited to this.

The gear position of the shift lever device 21 is a 1F position for only the first forward speed, which is manually switched, and a 2F position, which is up to the second forward speed, and a forward 1 position for automatically shifting the speed stage of the transmission 3. Speed, forward 2
A drive position D having a third speed, a third forward speed, and a fourth forward speed, and a neutral position N and a reverse position R that are manually switched.

The controller 22 receives a signal from a drive mode switch (not shown), a signal from a retarder switch (hereinafter referred to as a retarder SW), a signal from an on-key switch, and a speed signal from the transmission 3. Has been entered. Further, a first predetermined speed which is a predetermined upper limit value for protecting the drive system in accordance with the speed stage, a second predetermined speed which is a lower limit value, and a predetermined cooling water temperature are stored. A storage unit is provided, and the input signal from each of the above-described sensors and each switch is compared with the storage value of the storage unit to calculate the water temperature sensor 24.
When the actual cooling water temperature of the cooling water after the retarder oil cooling reaches a predetermined temperature (for example, 90 ° C.) and the main brake device is actuated by depressing the brake petal, the vehicle falls below the predetermined speed. Transmission 3
Is automatically shifted down from four steps to three steps. Also,
A comparison operation control unit is provided which starts the speed stage maintaining flag of the transmission 3 which is turned on when such shift-down control is performed and turned off when the normal program control is performed.

When the transmission 3 is shifted down, the lock-up clutch 2a incorporated in the torque converter 2 is released in order to alleviate the shock torque. After 0.5 seconds, the torque converter 2 is re-engaged, so that the slip of the torque converter 2 hardly causes a problem, and the rotation speed of the engine 1 increases without any trouble. Further, in order to protect each drive system, the engine 1 is controlled so that the rotation speed of the engine 1 does not exceed the predetermined rotation speed when the transmission is downshifted, and only when the vehicle speed falls below the predetermined speed during the downshifting. The shift down control of the transmission 3 is performed.

The shift down control of the transmission 3 is different from the normal automatic shift program control for traveling on a flat road, downhill or uphill, and the normal automatic shift control is performed by depressing the accelerator pedal 9. It is configured to return to program control. The normal automatic transmission program control means that when traveling on a flat road, downhill road, uphill road, etc., drivability is prioritized according to the traveling speed, engine speed and accelerator pedal depression amount, and A control method of a drive system (engine, torque converter, transmission) and a control device thereof for preventing unnecessary shifts in speed due to a shock or a change in speed (improvement of driving feeling). It is.

Hereinafter, the flowcharts shown in FIGS. 2 to 4 (A / P, T / M and B / P in the alphabets shown in the figures are an accelerator pedal, a transmission and a brake pedal, respectively). The method of braking by the transmission control device 20 of the wheel crane will be described according to (1). First, in step 1, the traveling speed of the wheel crane input from the vehicle speed sensor 25 is read, the speed stage of the transmission 3 at that time is read, and the water temperature is read. The actual cooling water temperature after the cooling of the retarder oil, which is input from the sensor 24, is read, and the routine proceeds to step 2.

In step 2, it is determined whether or not the work pump is operated, that is, whether the wheel crane is in the work mode for performing crane work or in the travel mode for traveling on a general public road. If it is determined that the wheel crane is in the traveling mode, the process proceeds to step 3, and if it is determined that the wheel crane is in the crane operation mode, the process proceeds to step 12, and the normal automatic transmission program control is performed to control the wheel crane. Traveling is controlled.

In step 3, the retarder SW is turned on
, That is, whether the retarder 7 is operable. In the case of Yes in which the retarder 7 is operable and the braking force can be exerted, the process proceeds to Step 4, and in the case of No in which the retarder 7 is not operated, the process proceeds to Step 12, and the normal automatic The traveling of the wheel crane is controlled by the shift program control.

In step 4, it is determined whether or not the accelerator pedal 9 is depressed, that is, whether or not the traveling wheel crane is being accelerated (whether the operator intends to accelerate). If it is determined that the accelerator pedal 9 has not been depressed and the wheel crane has not been accelerated (Yes), the retarder control device 1
0, the process proceeds to step 5, and if it is determined that the accelerator pedal 9 is depressed and the wheel crane is accelerating, the process proceeds to step 12, and the normal automatic transmission program control controls the wheel crane. Traveling is controlled. (When the accelerator pedal 9 is depressed, the control returns to the normal automatic transmission program control even in the control state of the transmission control device 20.)

In step 5, the shift lever device 2
It is determined whether or not the first shift lever 21a has been switched to the drive position D for automatically shifting the transmission 3. If it is determined that the shift lever 21a has been switched to the drive position D (Yes), the process proceeds to step 6, where the shift lever 21a is moved to the drive position D.
If it is determined that it has not been switched to No., the process proceeds to step 12, where the traveling of the wheel crane is controlled by the normal automatic transmission program control.

In step 6, the transmission control device 20 determines whether or not the transmission 3 is in the third gear position and the maintenance flag is OFF. In other words, if it is determined that the transmission 3 is not maintained at the third gear position, the process proceeds to step 7, where the speed gear position maintaining flag is ON, and it is determined that the transmission 3 is already maintained at the third gear position. If No, the process proceeds to step 11.

In step 7, it is determined whether or not the speed stage of the transmission 3 is at the fourth speed position.
That is, in the case of Yes where it is determined that there are four speed stages, the process proceeds to step 8, and when it is determined that there are three or less speed stages,
In this case, the routine proceeds to step 12, where the traveling of the wheel crane is controlled by the normal automatic transmission program control.

In step 8, the actual cooling water temperature after the cooling of the retarder oil detected by the water temperature sensor 24 is compared with a predetermined temperature (for example, 90 ° C.) to determine the actual cooling water temperature. If it is determined that the actual cooling water temperature is lower than the predetermined temperature, the flow proceeds to step 9; The traveling of the wheel crane is controlled.

In step 9, it is determined whether or not the brake pedal for operating the main brake device for braking the tires 5, 5 is depressed. In the case of Yes where it is determined that the brake pedal is depressed, the process proceeds to step 10, and it is determined that the brake pedal is not depressed.
In this case, the routine proceeds to step 12, where the traveling of the wheel crane is controlled by the normal automatic transmission program control.

In step 10, the traveling speed of the wheel crane is determined, and the traveling speed is determined to be the first predetermined value.
Is determined to be equal to or lower than the predetermined speed V ₁ (for example, 30 km / h), the transmission 3 is automatically shifted from the fourth gear to the third gear by the shift-down control of the controller 22 constituting the transmission control device 20. is shifted down the process proceeds to step 11, the traveling speed is the flow proceeds to step 12 in the case of No it is determined that the first faster than a predetermined speed V _1, the travel of the mobile crane is controlled in a normal automatic shift program control You. When the downshift control is performed, the speed stage maintaining flag of the transmission 3 is turned on. When there is a risk that the engine 1 may overrun due to downshifting, an alarm is issued by a buzzer or the like that is activated by the engine speed detected by the engine speed detection sensor 26.

In step 11, a comparison is made between the traveling speeds of the wheel cranes. When the traveling speed of the wheel crane is the second predetermined speed V ₂ (for example, 16 km / h)
Proceeds are travel control of the mobile crane in the normal automatic shift program control proceeds to step 12 to step 13 in the case of Yes it is determined that the following, the traveling speed of the mobile crane is than the second predetermined speed V ₂ If it is determined that the speed is too fast, the transmission control device 2
Control is returned to step 1 in order to continue the transmission control by 0, and control through the same steps as above is performed again. Note that, by performing the normal automatic shift program control, the speed stage maintaining flag of the transmission 3 is turned off.

In step 13, it is determined whether the engine key switch is turned off and the traveling of the wheel crane is stopped. In the case of Yes in which it is determined that the traveling of the wheel crane has been stopped, the control of the transmission 3 by the transmission control device 20 is stopped, and in the case of No in which it is determined that the wheel crane is running, the transmission control device 20 is stopped. Step 1 for continuation of transmission 3 control by
And the same transmission control as described above is performed again.

According to the transmission control device 20 having such a configuration, the transmission 3 from the fourth stage to the third stage in the temperature range where down regulation can be avoided.
Due to the shift down to the next stage, the rotation speed of the engine 1 is increased, the speed of the cooling water pump 1d and the cooling fan 1e is increased, and more cooling is performed and a large amount of cooling water is supplied to the oil cooler 8a. And with this,
Since the braking force that can be absorbed by the engine 1 increases, the burden ratio of the braking force of the retarder 7 decreases, down regulation can be easily avoided, and the vehicle descends safely while braking with the retarder 7 even on a long slope. be able to. Unlike the retarder automatic control devices according to Conventional Examples 1 and 2, the vehicle does not run at the commanded vehicle speed set by the commanded vehicle speed setting device. And can drive safely. Further, the transmission control by the transmission control device 20 can be automatically performed only by depressing the brake pedal 9, and the transmission control by the transmission control device 20 is released only by depressing the accelerator pedal. Since it is switched to control and there is no need to perform troublesome switching operation of the shift lever, the driver can concentrate on driving and contribute to the improvement of safe traveling of the wheel crane. Further, unlike the braking force control method according to Conventional Example 3, there is no need to mount a third-valve type engine brake auxiliary system on the engine 1 and there is no need to make the engine 1 a special specification. Use is possible), which is advantageous from an economical point of view.

In the above, the transmission 3
The transmission control device 20 provided with the shift lever device 21 having the four forward drive positions D for shifting the gears of the first speed range has been described as an example. However, advance 6
A shift lever device having a stepped drive position D can be employed. Then, in the case of the shift lever device having such a drive position D, the transmission is first shifted down from the sixth stage to the fifth stage as in Conventional Examples 2 and 3, and nevertheless the actual cooling water is used. If the temperature is higher than the predetermined temperature, it is possible to perform a two-stage downshift control in which the transmission is further downshifted from five stages to four stages. The technical idea of the present invention can be applied to a vehicle equipped with the vehicle.

In the above description, the case where the transmission control by the transmission control device 20 is applied to a wheel crane has been described as an example. However, not only a dump truck but also many other large vehicles and construction equipment vehicles are used. The present invention can be applied to a vehicle having a large total vehicle weight.

[0045]

As described in detail above, claim 1 of the present invention
According to the transmission control method for a wheel crane according to the second aspect or the transmission control apparatus for a wheel crane according to the third or fourth aspect of the present invention, the actual cooling water temperature after the retarder oil cooling is higher than the predetermined temperature. When the brake pedal is depressed and the traveling speed of the wheel crane falls below a predetermined speed, the transmission is automatically shifted down and the engine speed increases, so that more cooling water is cooled. Since the oil is supplied to the oil cooler that cools the retarder oil, down regulation of the retarder is avoided, and the retarder that exerts normal braking force, the main brake device, and the exhaust brake drive safely on long hills and go downhill. can do.

Then, instead of running at the commanded vehicle speed as in the automatic retarder control device according to the conventional example 2 or 3,
Since the vehicle can travel at any traveling speed within the predetermined speed, it can be adopted for a wheel crane traveling on a general public road. Also, as in the braking force control method according to Conventional Example 3, a third engine is used. There is no need to mount a valve-type engine brake auxiliary system, and there is no need to make the engine a special specification.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing an arrangement of main components of a wheel crane according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an operation of transmission control by the transmission control device shown in FIG. 1;

FIG. 3 is a flowchart illustrating an operation of transmission control by the transmission control device shown in FIG. 1;

FIG. 4 is a flowchart for explaining an operation of transmission control by the transmission control device shown in FIG. 1;

FIG. 5 is a schematic plan view of a typical vehicle according to Conventional Example 1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 1a ... Radiator, 1b ... Engine water jacket, 1c ... Exhaust manifold, 1d ... Cooling water pump, 1e ... Cooling fan 2 ... Torque converter, 2a ... Lock-up clutch 3 ... Transmission 4 ... Axle 5 ... Tire 6 ... Cooling water circulation line, 6a: cooling water supply line, 6b: cooling water return line, 7: retarder. 7a ... oil cooler 8 ... exhaust brake 9 ... accelerator pedal 10 ... retarder control device, 11 ... retarder control lever device, 11a ... control lever, 12 ... retarder controller, 13 ... retarder control valve, 14 ...
Water temperature sensor for retarder control, 15: compressed air supply air source 20: transmission control device, 21: shift lever device, 21a: shift lever, 22: controller,
23: accelerator depression detection sensor, 24: water temperature sensor,
25: Vehicle speed sensor, 26: Engine speed detection sensor

Claims (4)

[Claims] The temperature of cooling water after cooling the retarder oil supplied from the engine side is detected, and the detected actual cooling water temperature is compared with a predetermined temperature to determine the level of the cooling water.
When the actual cooling water temperature exceeds a predetermined temperature, the transmission automatically shifts down when the wheel crane falls below a predetermined speed or below a predetermined engine speed by depressing a brake pedal that operates a main brake device. A transmission control method for a wheel crane, wherein when the actual cooling water temperature is equal to or lower than a predetermined temperature, the speed stage of the transmission is controlled based on normal automatic shift control. 2. The transmission control method for a wheel crane according to claim 1, wherein the control of the transmission is returned to a normal automatic shift control by depressing an accelerator pedal. 3. A brake pedal for operating a main brake device for braking a traveling wheel, wherein a braking force is controlled by a retarder control device, and the retarder is driven by cooling water after cooling an engine which is a driving source of the traveling wheel. A transmission control device for a wheel crane that controls the transmission of a wheel crane provided with a fluid type retarder having an oil cooler for cooling oil, the retarder oil being returned to the engine side from the oil cooler by the transmission control device. The actual cooling water temperature of the cooling water after cooling is compared with a predetermined temperature, and when the actual cooling water temperature exceeds the predetermined temperature, the wheel crane is moved below the predetermined speed by depressing the brake pedal or When the engine speed falls below the A transmission control device for a wheel crane, characterized by adding a control unit for automatically shifting down the transmission. 4. The transmission control device for a wheel crane according to claim 3, wherein an automatic return control unit that returns to normal automatic shift control by depressing an accelerator pedal is added to the transmission control device.