JP3562589B2 - Inching hydraulic control device, construction machine equipped with the same, and method of determining inching hydraulic pressure - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an inching hydraulic control device for so-called inching travel, which travels slowly while rotating an engine in a construction machine such as a bulldozer, a construction machine equipped with the same, and a method of determining inching hydraulic pressure .
[0002]
[Prior art]
The fine running and stopping of the bulldozer in forward and backward traveling are performed by depressing an inching pedal and operating an inching valve, and the inching valve makes the forward and backward clutch hydraulic pressure variable by a pedal stroke and makes a slight traveling in a half clutch state.
In the conventional inching control, the spool stroke of the inching valve moves according to the depression amount of the pedal, and the relationship between the spool stroke amount (S) and the inching oil pressure (P) changes as shown in FIG. Inching valve inoperative when the spool stroke (S) becomes 0 inching pressure (P) is the set pressure P1 becomes clutch is connected, inching valve fine operation time from P 2 of P 0 in accordance with the depression amount of the pedal you forward or reverse clutch in the half-clutch state by regulating in the range. At the stroke end of depressing the inching pedal, the inching oil pressure becomes P0, the forward or reverse clutch is disengaged, and the vehicle stops.
[0003]
[Prior art]
[Problems to be solved by the invention]
Since the inching oil pressure is determined only by the inching valve stroke as described above, it is acceptable if the relationship between the spool stroke (S) and the oil pressure (P) is set to a gentle oil pressure gradient such as a as shown by the broken line A in FIG. Minimal running with little load fluctuation but no traction. As b Conversely, Then tightly hydraulic gradient, there is a problem that is large allowable load variation can not be finely travel.
[0004]
The present invention has been made to solve the above-mentioned problems of the prior art, and makes the inching oil pressure variable with respect to the inching stroke according to the load, absorbs the load fluctuation, and provides fine running performance and traction at low vehicle speed. It is an object of the present invention to provide an inching hydraulic control device capable of improving the performance .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first invention of the present application, an inching hydraulic control device used for controlling a hydraulic pressure supplied to a hydraulic actuation clutch to be subjected to an inching operation of a vehicle having an inching operation means, An inching operation amount sensor for detecting an operation amount of the inching operation means; an input-side rotation sensor for detecting an input-side rotation speed of the hydraulically operated clutch; and an output side for detecting an output-side rotation speed of the hydraulically operated clutch. A rotation sensor, a signal from the inching operation amount sensor, a signal from the input-side rotation sensor, and a signal from the output-side rotation sensor are input, and a signal for controlling a hydraulic pressure supplied to the hydraulic operation clutch is generated. Calculating the inching oil pressure of the hydraulically actuated clutch by the controller. A base oil pressure is determined based on a signal of the output sensor, a clutch slip ratio is obtained from an output signal of the input rotation sensor and an output signal of the output rotation sensor, and the base oil pressure is corrected by the clutch slip ratio. The value is an inching oil pressure.
The inching control device according to the second invention of the present application is the inching control device according to the first invention of the present application, wherein the controller is configured to control the hydraulically actuated clutch based on an arithmetic expression having a relationship that the larger the clutch slip ratio, the larger the inching oil pressure. The calculation of the inching hydraulic pressure is performed.
The inching control device according to the third invention of the present application is the inching hydraulic control device according to the first invention or the second invention of the present application, wherein the controller further includes an output signal of the input-side rotation sensor and an output signal of the output-side rotation sensor. , The amount of frictional heat generated by the clutch is calculated, and it is determined whether or not the calculated amount of frictional heat is greater than a predetermined reference value.
A construction machine according to a fourth invention of the present application is equipped with the inching control device according to any one of claims 1 to 3.
According to a fifth aspect of the present invention, in a method for determining the inching oil pressure of the hydraulically actuated clutch of a vehicle having an inching operation means and a hydraulically actuated clutch to be subjected to the inching operation, the base oil pressure is determined based on an operation amount of the inching operation means. The clutch slip ratio is determined from the rotational speeds of the input side and the output side of the hydraulically operated clutch, and the base hydraulic pressure is corrected by the clutch slip ratio to obtain an inching hydraulic pressure.
[0006]
[Action]
Since the inching oil pressure control device as described above is used, from the base inching oil pressure of clutch slip ratio 0 to the clutch slip ratio 1 in which the base inching oil pressure is positively corrected according to the clutch slip ratio, according to the stroke of the inching pedal. The variable inching hydraulic pressure with the hydraulic pressure range of is obtained, and even if the inching pedal stroke is constant, the load fluctuation at low vehicle speed can be absorbed, and the inching hydraulic pressure that achieves both fine running performance and traction force is exhibited .
[0007]
【Example】
An embodiment of an inching control device according to the present invention will be described in detail with reference to the accompanying drawings.
[0008]
FIG. 1 is an explanatory diagram of a transmission including an inching control device according to the present invention.
In FIG. 1, the transmission 10 includes a forward / reverse switching unit 20 and a speed switching unit 30 each of which is a planetary gear device. The input shaft 11 of the transmission 10 is connected to an engine 50 via a damper 40. The output shaft 12 is connected to the speed switching unit 30, and a binion 45 of the clutch-type steering device 40 is fixed to a tip of the output shaft 12. A gear 46 is meshed with the pinion 45 so that the rotation of the output shaft 12 can be transmitted to a shaft 47 orthogonal to the output shaft 12. Steering clutches 43 and 44 are provided at both ends of the shaft 47, and steering brakes 41 and 42 are attached to output shafts of these clutches 43 and 44. These brakes 41 and 42 are operated by hydraulic pressure output by electronically controlled modulating valves (ECMV ( Electro-hydraulic Control Valve )) 51 and 52 serving as brake driving units, and steering clutches 43 and 44 are correspondingly operated. It is controlled by a hydraulic pressure supplied through an ECMV ( Electro-hydraulic control valve ) provided.
[0009]
On the other hand, the input shaft 11, the intermediate shaft 13, and the output shaft 12 of the transmission 10 are provided with rotation sensors 71, 72, 73, respectively, so that the rotation speed of each shaft can be detected. Further, the reverse clutch 21, the forward clutch 22, the third speed clutch 31, the second speed clutch 32, and the first speed clutch 33 of the transmission 10 are ECMV ( Electro-hydraulic) provided as corresponding clutch driving units. The control valves 55 to 59 are actuated by hydraulic pressure supplied from the main relief valve 60 to fix or release the corresponding carrier or ring gear.
[0010]
In the cab 90 of the bulldozer, a brake pedal 92 and an inching pedal 93 are provided on the floor in front of a driver's seat 91, and a display panel 94 is arranged at the forefront. Further, a blade lever 95 for operating a blade is disposed on the front right side of the driver's seat 91, and a steering lever 96 for controlling the traveling direction of the bulldozer is provided on the front left side. The operation signal of the steering lever 96 is transmitted to the transmission controller (T / M controller) 81 and the steering controller (S / S) constituting the shift control unit 80 together with the operation signals (depressing signal) of the brake pedal 92 and the inching pedal 93. T controller) 82.
[0011]
T / M controller 81 input shaft 11 of the transmission 10 further rotation sensor 71 to 73 is detected, the intermediate shaft 13, with the rotational speed signal of the output shaft 1 2, of the clutches of the transmission 10 ECMV (electro-hydraulic the control valve) 55 to 59, transmits an electric signal to output a hydraulic pressure modulation control and the clutch engagement pressure controlled fluid pressure, ECMV (electro-hydraulic control valve) 55 to 59 in an electrical signal received Outputs the corresponding pressure fluid . The ECMV ( Electro-Hydraulic Control Valve ) 55, 56 receives the electric signal output from the T / M controller 81 to the forward / reverse clutches 22, 21 and outputs the same pressure fluid as described above, as described in detail later. I do.
[0012]
On the other hand, the S / T controller 82 receives fill signals from ECMVs ( electro-hydraulic control valves ) 51 to 54 for controlling the clutch and brake of the steering device 40 in addition to the signals from the steering lever 96 described above. It is input and is electrically connected to the T / M controller 81 via a signal line, and exchanges data with the T / M controller 81.
[0013]
When the inching pedal 93 is operated in the embodiment configured as described above, control based on the flowchart shown in FIG. When the inching pedal 93 is depressed, a signal indicating that the inching pedal 93 is depressed is input to the T / M controller 81 (step 01), the rotation speed ωE of the T / M input shaft 11 is detected by the rotation sensor 71, and the T / M intermediate shaft 13 Is detected by the rotation sensor 72 and input to the T / M controller 81, and the depression amount S of the inching pedal 93 is input to the T / M controller 81, and a current control signal corresponding to the depression amount S is sent to the ECMV. ( Electro-hydraulic control valve ) 55 or 56 (ECMV ( Electro-hydraulic control valve ) 56 for forward travel, ECMV ( Electro-hydraulic control valve ) 55 for reverse travel) to control the hydraulic pressure of clutch 21 or 22. It is determined whether or not the depression amount S of the inching pedal 93 is larger than the reference value (step 003). If the depression amount S is larger than the reference value (Y), it is determined that the bulldozer is stopped, and the T / M controller is determined. 81 instructs ECMV ( Electro-Hydraulic Control Valve ) 51, 52 to actuate the brakes 41, 42 to actuate the brakes (step 03). If the value is smaller than the reference value (N), an inching operation is performed. The clutch slip rate (α) is determined as follows:
α = 1−ωC / ωE
(Step 05).
When the clutch slip ratio (α) is calculated, the inching oil pressure P (α) is given by
P (α) = Kp × α + P0 (S)
Where Kp is a hydraulic pressure correction coefficient corresponding to the slip ratio, and P0 (S) is a base hydraulic pressure (step 06).
The above equation will be described with reference to FIG. The horizontal axis indicates the depression amount (S) of the inching pedal 93, and the vertical axis indicates the hydraulic pressure (P). The straight lines a, b, and c indicate the depression amount (S) of the inching pedal 93 as a base and the hydraulic pressure (P). For example, if the external load is small and the clutch does not slip, the relationship between the depression amount (S) of the inching pedal 93 and the oil pressure (P) shown by the straight lines a, b, and c is obtained. This is a line indicating the upper limit that can be increased. For example, a value depression amount of the inching pedal 93 has added value clutch slip rate (alpha) is multiplied by 50% in the correction coefficient KP slippery When it is 50% based hydraulic P0 (S0) (0. 5 ) with S0 The following equation is obtained.
(Equation 3)
P (α) = P0 (S0) + KP × 0 . 5
For example, if the depression amount of the inching pedal 93 is S0 and the clutch slip ratio (α) is 100%, the value is obtained by multiplying the base oil pressure P0 (S0) and the oil pressure gradient KP by 100% (1). It becomes as shown in the formula.
(Equation 4)
P (α) = P0 (S0) + KP × 1
In the inching operation, when the clutch slips, the depression amount of the inching pedal 93 is reduced, so that there is a relationship between the depression amount S of the inching pedal 93 and the inching oil pressure P (α) as shown by the dotted line indicated by the arrow A.
When the inching oil pressure P (α) is calculated, the T / M controller 81 outputs a current control signal to the ECMV ( electro-hydraulic control valve ) 55 or the ECMV ( electro-hydraulic control valve ) 56 to operate the clutch 21 or 22 (step). 07) Then return to step 01. Further, I1 is the input equivalent inertia moment, I2 is the inertia of the vehicle, TE is the output torque of the engine, TC is the output torque of the F clutch 22 or the R clutch 21, TL is the running resistance of the vehicle, and ωE0 is the engine torque at time 0. The rotation speed, ωE (t) is the engine rotation speed after time t, ωC0 is the rotation speed of the T / M intermediate shaft 13 at time 0, and ωC (t) is the rotation of the T / M intermediate shaft 13 after time t. Assuming the speed, the frictional heating value QC of the clutch is obtained by the following equation (step 08).
(Equation 5)
(Equation 6)
It is determined whether the frictional heat QC of the clutch is larger than a reference value. If it is larger (Y), an alarm is issued (step 10). If not (N), the process returns to step 01 (step 09).
[0014]
FIG. 4 is a diagram for explaining the relationship between the vehicle speed and the tractive force. The vertical axis represents the tractive force, the horizontal axis represents the vehicle speed, the vertical inclined line represents the clutch slip ratio, and the horizontal inclined lines (S0, S1) represent the amount of depression of the inching pedal 93. ΔF indicates the range of the tractive force that changes according to the hydraulic gradient KP shown in FIG. For example, when the depressed amount of the inching pedal 93 is gradually reduced from S0, the broken line B is obtained. At point B1, since the clutch slip ratio α = 1, the vehicle speed is 0 and the tractive force F (α) is small, but at B2, the amount of depression of the inching pedal 93 decreases and the inching oil pressure increases as approaching S1 ( (See FIG. 3) The vehicle speed increases and the tractive force also increases.
[0015]
As a second embodiment of the present invention, when a signal depressing the inching pedal 93 is input to the T / M controller 81 in step 01 of the flowchart shown in FIG. 2, the T / M controller 81 sends a signal to the engine control device 57. The output is made to reduce the rotation speed of the engine 50, and then a step of going to step 02 is added.
[0016]
【The invention's effect】
As described above, according to the present invention, the inching oil pressure can be changed by the slip ratio of the clutch using the controller, so that not only the fine running can be performed but also the tractive force can be increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a transmission including an inching control device according to the present invention.
FIG. 2 is a flowchart for explaining control performed in a T / M controller.
FIG. 3 is a diagram for explaining an arithmetic expression.
FIG. 4 is a diagram for explaining a relationship between a vehicle speed and a tractive force. FIG. 5 is a diagram showing a relationship between a depression amount of a conventional inching pedal and an inching oil pressure.
[Explanation of symbols]
10: transmission, 11: input shaft, 13: intermediate shaft, 21: reverse clutch, 22: forward clutch, 31: 3rd speed clutch, 32: 2nd speed clutch, 33: 1st speed clutch, 50: engine, 55, 56: electronically controlled modulating valve, 71: engine rotation sensor, 72: intermediate shaft rotation sensor, 81: transmission controller.

Claims (5)

An inching hydraulic control device used for controlling a hydraulic pressure supplied to a hydraulically actuated clutch to be subjected to the inching operation of a vehicle having inching operation means,
An inching operation amount sensor for detecting an operation amount of the inching operation means,
An input-side rotation sensor that detects an input-side rotation speed of the hydraulically actuated clutch,
An output-side rotation sensor that detects the output-side rotation speed of the hydraulically actuated clutch,
A signal is input to the signal of the inching operation amount sensor, the signal of the input side rotation sensor, and the signal of the output side rotation sensor, and a controller is provided for generating a signal for controlling a hydraulic pressure supplied to the hydraulically actuated clutch. ,
The controller calculates the inching oil pressure of the hydraulically actuated clutch by determining a base oil pressure based on a signal of the inching operation amount sensor, and determines a clutch based on an output signal of the input side rotation sensor and an output signal of the output side rotation sensor. An inching hydraulic pressure control device, wherein a value obtained by calculating a slip ratio and correcting the base oil pressure by the clutch slip ratio is set as an inching oil pressure. The inching hydraulic control device according to claim 1,
The controller calculates the inching oil pressure of the hydraulic clutch based on an arithmetic expression having a relation that the inching oil pressure increases as the clutch slip rate increases.
The inching control device according to claim 1, wherein: The inching hydraulic control device according to claim 1 or 2,
The controller further calculates a frictional heating value of the clutch from the output signal of the input-side rotation sensor and the output signal of the output-side rotation sensor, and determines whether the frictional heating value obtained by the calculation is larger than a predetermined reference value. Is to determine
The inching hydraulic control device according to claim 1 or 2, wherein: A construction machine equipped with the inching control device according to claim 1. A method for determining the inching oil pressure of the hydraulically operated clutch of a vehicle having an inching operation means and a hydraulically operated clutch to be subjected to the inching operation,
Determine the base oil pressure based on the operation amount of the inching operation means,
Determine the clutch slip rate from the input side and output side rotation speed of the hydraulically actuated clutch,
A method for determining an inching hydraulic pressure of a hydraulically operated clutch, wherein the base hydraulic pressure is corrected based on the clutch slip ratio to obtain an inching hydraulic pressure .

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