JP3475490B2 - Travel device brake control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for a traveling device. 2. Description of the Related Art A conventionally known Japanese Patent Application Laid-Open No. 5-85398 discloses a power steering lever provided in a driver's seat, a position sensor for detecting when the power steering lever is tilted by a predetermined angle, and a position sensor. It describes a control unit that determines the deceleration ratio of the left and right brake pressure reducing valves based on a signal from a sensor, and turns with a desired turning radius. [0003] In the above-mentioned known example, since a brake pressure reducing valve operated by a solenoid is used, the oil temperature is low immediately after the engine is started, and when the oil temperature is low, the electric resistance of the solenoid is low. When the power steering lever is tilted at a normal angle, the left and right brakes are more controlled than the operator's operation feeling. The power is strong and turns sharply.In addition, if the oil temperature increases during work, the electric resistance of the solenoid increases and the current value decreases, so the hydraulic pressure supplied from the brake pressure reducing valve to the brake hydraulic cylinder chamber Therefore, even if the power steering lever is operated at the same tilt angle as immediately after starting the engine, the braking force of the left and right brakes is weak, the turning radius becomes large, and the There is a problem that the crop intervals are not the same. [0004] It is an object of the present invention to stabilize, secure and facilitate brake control. SUMMARY OF THE INVENTION Accordingly, the present invention provides a position sensor 48 for detecting when a power steering lever provided in a driver's seat is tilted by a predetermined angle, and a left and right signal based on signals from the position sensor 48. Brake pressure reducing valves 46, 4
6 having a control unit 49 for operating the solenoid 47, the control unit 49 presets several types of pressure characteristics for operating the solenoid 47, and the control unit 49 is provided on the lower side of the brake pressure reducing valves 46, 46. The brake control device of the traveling device is configured to judge whether or not the selection of the pressure characteristic is appropriate based on the detected oil pressure value measured by the provided brake pressure sensor 50 and to re-control the same. An embodiment of the present invention will be described with reference to the drawings.
Reference numeral denotes a transmission case of a traveling device of a working machine such as a combine, in which an input shaft 2 is provided horizontally at an upper position, and a hydraulic transmission (hydrostatic transmission) 3 is attached to one end of the input shaft 2. A large gear 4 and a small gear 5 are loosely fitted to the input shaft 2, and a speed increasing clutch 6 is provided between the large gear 4 and the small gear 5 and the input shaft 2. 7 is a first intermediate shaft, 8 is a small gear that always meshes with the large gear 4, 9 is a small gear 5
, A transmission gear fixed to the first intermediate shaft 7, 11 a sub-transmission shaft, 12 a small gear loosely fitted to the sub-transmission shaft 11, 13 a large gear, and 14 a large gear 13. A transmission gear 15 provided so as to rotate integrally therewith is a transmission member provided slidably in the axial direction on the auxiliary speed change shaft 11 between the transmission gear 14 and the small gear 12. Is transmitted to the auxiliary transmission shaft 11. Reference numeral 16 denotes a drive gear fixed to the auxiliary transmission shaft 11, and 17 denotes a side clutch shaft 1.
The passive gear 8 is fixed to the driving gear 16 at all times. The present invention relates to the control of the left and right brakes 19, 19 'in a turning operation performed by a power steering lever (not shown) when the vehicle travels. The configuration of the left and right brakes 19, 19' is as follows. Although any of them may be used, an example is shown below, and the side clutch shaft 1
Left and right rotating drums 22 and 22 'are provided on both left and right sides of 8,
Left and right brakes 19, 1 are provided in left and right rotating drums 22, 22 '.
9 'and left and right clutches 23, 23' are provided. The left and right brakes 19, 19 'and the left and right clutches 23, 2
Since the structure of 3 ′ is symmetrical, it will be described with the same reference numerals. [0008] As shown in FIG.
A partition member 24 that rotates integrally with the left and right rotating drums 22 and 22 ′ is provided at a central portion inside 2 ′, and an inner cylindrical portion 25 and an outer cylindrical portion 26 are connected to the partition member 24, and an inner cylindrical portion 25 is formed.
A hydraulic cylinder chamber 27 for brakes is provided inside the outer cylindrical portion 26 and outside the partition member 24, and a piston 28 is provided in the hydraulic cylinder chamber 27 for brakes.
Numeral 8 is configured to be slidable in the axial direction of the side clutch shaft 18. On the inner surface of the outer tubular portion 26 outside the partition member 24, a rotating disk 29 for braking that rotates together with the left and right rotating drums 22 and 22 'is provided.
Is a fixed disk 30 provided on the transmission case 1 side.
Slidably in contact with the left and right brakes 19, 19 '.
Is composed. A clutch-in cylinder chamber 31, a clutch-off cylinder chamber 32, and a piston 33 of a hydraulic cylinder for a clutch are provided in the inner cylinder part 25 and the outer cylinder part 26 and inside the partition member 24. Is configured to be slidable in the axial direction of the side clutch shaft 18. On the inner surface of the outer cylindrical portion 26 inside the partition member 24,
A clutch disk 34 that rotates together with the left and right rotating drums 22 and 22 ′ is provided.
Is composed. 36, 36 'are left and right rotating drums 22, 2
A side clutch gear that rotates or stops together with 2 ′, and is provided rotatably with respect to the side clutch shaft 18. The transmission case 1 has a turn mode by a turn mode switching lever, a pivot mode in which one of the left and right left and right brakes 19 and 19 'applies a brake to the rotation of the axle, and a left and right axle. Of these, it is possible to switch between a gentle turning mode in which the axle inside the turning is driven and rotated at a predetermined deceleration ratio with respect to the rotation speed of the axle outside the turning, and a spin turn mode in which the left and right axles are reversed with each other. is there. 37 and 37 'are reduction shafts for transmitting rotation to the axle, 38 is a mode selection shaft for selectively transmitting rotation to the reduction shafts 37 and 37', 39 and 39 'are mode selection clutches, and 40 is a mode selection shaft. A mode switching shaft for transmitting low-speed rotation or reverse rotation to 38, 41 is a spin mode gear loosely fitted to the mode switching shaft 40, 42 is a slow turning mode gear, 43 is a spin mode gear 41 and a slow turning mode gear. A sliding gear provided on the mode switching shaft 40 between the gears 42;
Denotes a neutral position located between the spin mode gear 41 and the slow turning mode gear 42, and slides right and left to engage with either the spin mode gear 41 or the slow turning mode gear 42 to rotate. The shifter 44 switches between a spin position and a gentle turning position. FIG. 3 shows a hydraulic circuit diagram of the present invention.
5 is a left and right clutch switching valve, 46 and 46 are left and right brake pressure reducing valves, and the brake pressure reducing valve 46 is configured to be operated by a solenoid 47. FIG. 4 is a block diagram.
8 is a power steering lever position sensor, 49 is a control unit, and 50 is a brake pressure sensor provided below the left and right brake pressure reducing valves 46, 46, respectively. When the power steering lever is tilted, the tilt angle is electrically detected by the position sensor 48. In response, the control unit 49 outputs the tilt angle to the solenoid 47 of the brake pressure reducing valve 46, and outputs the brake hydraulic cylinder. Although the hydraulic pressure in the chamber 27 is changed to change the braking force of the left and right brakes 19 and 19 ′, the solenoid 47 of the brake pressure reducing valve 46 changes the electric resistance of the coil due to a change in oil temperature. As a result, the oil pressure supplied from the brake pressure reducing valve 46 to the brake hydraulic cylinder chamber 27 changes. That is, even when the power steering lever is at the same tilt angle position, when the oil temperature is low, the electric resistance of the solenoid 47 is low and the current value is large, so that the oil is sent from the brake pressure reducing valve 46 to the hydraulic cylinder chamber 27 for brake. If the output hydraulic pressure is high, and if the oil temperature is high, the electric resistance of the solenoid 47 is high and the current value is low, the oil is sent from the brake pressure reducing valve 46 to the brake hydraulic cylinder chamber 27 (output). The operating hydraulic pressure is lower. By preventing the output of the brake pressure reducing valve 46 from changing due to a change in the oil temperature, the brake pressure corresponding to the tilt angle of the operation of the power steering lever is kept constant. The brake pressure sensor 50 is provided in the
0, the hydraulic pressure is measured, and the detected value of the brake pressure sensor 50 is fed back to the control unit 49 to detect and determine a change in hydraulic pressure due to a change in oil temperature. The control unit 49 sets several types of pressure characteristics preset in a memory. Of these, the pressure characteristic that provides an optimum output with respect to the oil temperature at this time is selected, and the solenoid 47 is re-controlled. The measurement of the oil pressure by the brake pressure sensor 50 is performed at an arbitrary predetermined time, for example, every 5 seconds or every 10 minutes from the start of the work (at the time of starting the engine). A characteristic is selected (meaning that the control unit 49 selects and changes the pressure characteristic every predetermined time). FIGS. 7 to 9 show embodiments relating to the conditions under which the control section 49 selects and changes the pressure characteristics. As shown in FIG.
The pressure characteristic is selectively changed every 1 to N for a predetermined time (when the control unit 49 selects and changes the pressure characteristic), but when the power steering lever operation S is performed between the predetermined time 1 and the predetermined time 2 The hydraulic pressure at this time is applied to the brake pressure sensor 50.
Is measured, and as described above, the control unit 49
Selects the pressure characteristic. At this time, when the operation S is performed a plurality of times, the latest operation S after a predetermined time has elapsed is set as a reference,
Until the next predetermined time, control is performed based on the selected hydraulic characteristics. Therefore, the control is performed accurately based on the latest power steering lever operation every predetermined time. Further, there is no operation S between the predetermined time 2 and the predetermined time 3, but at this time, the control based on the hydraulic pressure characteristic selected last time is continued. Left and right brake by power steering lever 1
This is because there is no need to correct when there is no operation on 9, 19 '. In this case, the detection value measured by the brake pressure sensor 50 is one of the tilt angles during the operation of a certain power steering lever, and during operation, the solenoid 47
Changes the engraving and oil pressure, so that it may not be easy to compare the set oil pressure at the power steering lever position with the detection value of the brake pressure sensor 50. For this reason, the control unit 49 sets the hydraulic pressure characteristic to be corrected and changed every predetermined time.
The output corresponding to the tilt angle of the power steering lever when measured by the brake pressure sensor 50 is set to the same output within a certain range, making it easy to compare with the detection result of the brake pressure sensor 50 and accurately selecting the hydraulic characteristics. (Note that after selecting the hydraulic characteristic, the output becomes a normal output corresponding to the tilt angle of the power steering lever as shown in FIG. 9). In the embodiment of FIGS. 10 and 11, when the power steering lever is tilted to the position where the left and right brakes 19 and 19 'are locked, the brake pressure sensor 50 detects the hydraulic pressure at this time, and the control unit 49 The difference between the oil pressure and the set oil pressure is stored, and the oil pressure characteristic is selected at the next predetermined time based on the difference. At this time, when the power steering lever has operated the lock range a plurality of times, the control unit 49 selects the pressure characteristic when correction is necessary based on the detected value immediately before the predetermined time. Next, the operation will be described. When the engine is started, the engine speed is raised to a certain speed, and when the engine is started, the control unit 49 supplies oil to the left and right clutch switching valves 45, 45 to connect the clutch disks 34 and the clutch disks 35 of the left and right clutches 23, 23 '. Abut the left and right clutches 23,
In this state, the rotation of the engine is shifted by the hydraulic continuously variable transmission 3 and transmitted to the input shaft 2, and the rotation of the input shaft 2 is transmitted to the side clutch shaft 18, and The rotation of the shaft 18 is applied to the partition members 24, 2
4 ′, the left and right rotating drums 22 and 22 ′, and the left and right rotating drums 2 via the clutch disc 35 and the clutch disc 34.
2, 22 ', and the rotation of the left and right rotating drums 22, 22' is transmitted to the side clutch gears 36, 36 'engaged with the left and right rotating drums 22, 22', from the side clutch gears 36, 36 '. The rotation is transmitted to the reduction shafts 37 and 37 ′ via the intermediate gears to drive and drive the traveling device. (Note that the rotation of the input shaft 2 by the hydraulic transmission 3 is reversed to be similar to the above. Reverse on the transmission route). When the turn mode switching lever is set to the pivot rotation mode and the power steering lever is tilted left or right, one of the left and right clutches 23 and 23 'is set to "disengage", and the disengaged left and right clutches 23 and 23' are turned off. , 2
3 'is the oil transfer into brake hydraulic cylinder chamber 27 of for example the left brake 1 9 correspond to the fixed disk 30 the piston 28 is fixed to the rotary disk 29 to the transmission case 1
, And the braking of the rotating disk 29 is transmitted to the side clutch gear 36 via the left rotating drum 22, and the rotation of the reduction shaft 37 corresponding to the side clutch gear 36. Is decelerated to perform a left-turn pivot turn. In this case, a signal is output to one of the left and right brake pressure reducing valves 47 and 47 'corresponding to the inside of the turning direction to activate one of the left and right brakes 19 and 19'. When the oil temperature is low, the electric resistance of the solenoid 47 is low, and the current value is large. Therefore, the hydraulic pressure to be supplied to the brake hydraulic cylinder chamber 27 from the brake pressure reducing valve 46 is high, so that the power steering lever is tilted to a normal angle. Even the left and right brakes 1
The braking force of 9 and 19 'is strong and turns sharply. Further, when the oil temperature during operation increases, the electric resistance of the solenoid 47 increases, and the current value decreases.
Since the oil pressure to be supplied to the brake hydraulic cylinder chamber 27 is lower, even if the power steering lever is operated at the same tilt angle as immediately after the start of the engine, the braking force of the left and right brakes 19 and 19 'is weak and the turning radius is large. Become. According to the present invention, the left and right brake pressure reducing valves 46, 46
The hydraulic pressure is measured by a brake pressure sensor 50 provided on the lower side of the vehicle, and several types of pressure characteristics for operating the solenoid 47 are set in the control unit 49. performs measurement of the hydraulic by the brake pressure sensor 50 for each any given time or for each such every 10 minutes 5 seconds, based on the detection result, according to the pressure characteristic control unit 49 that is set in advance (the controller 49 of output change characteristic) to the solenoid 47, to select an optimal pressure characteristics in order to obtain a set pressure for the tilting operation of the power steering lever after hydraulic change (output variation characteristics to the solenoid 47 by the controller 49). For example, when the brake pressure sensor 50 detects that the oil pressure is high immediately after the start of work, the control unit 49 shown in FIG.
Selects the optimum characteristic sequentially from the hydraulic characteristic n toward the hydraulic characteristic 1, makes the pulse output to the solenoid 47 shorter than before the hydraulic characteristic change, reduces the current value, thereby lowers the hydraulic pressure, and reduces the power steering lever. The output of the brake pressure reducing valve 46 corresponding to the tilt operation angle is set to the set pressure. Further, the brake pressure sensor 50 is
Conversely, if it detects that the oil pressure has dropped during work,
The pressure characteristic is shown in FIG.
The optimum characteristics are sequentially selected toward the hydraulic pressure characteristics n, the pulse output to the solenoid 47 is made longer than before the change in the hydraulic pressure characteristics, and the current value is increased.
The output of the brake pressure reducing valve 46 corresponding to the power steering lever tilting operation angle is set to the set pressure. Figures 7-9
In this embodiment, when the control unit 49 selects and changes the hydraulic characteristics, the latest operation of the power steering lever after a lapse of a predetermined time is targeted, and the brake pressure sensor 5
Since the control unit 49 selects the pressure characteristic based on the detected value of 0, the control is performed based on the latest detected value every elapse of a predetermined time, so that the control is accurate and the turning with respect to the power steering lever operation can be performed in the same manner. Can be. In this case, the controller 49 sets the output corresponding to the tilt angle of the power steering lever to the same output within a certain range when it is time to select and change the hydraulic pressure characteristic. This facilitates comparisons and allows accurate selection of hydraulic characteristics. In the embodiment of FIGS. 10 and 11, when the power steering lever is tilted to the position where the left and right brakes 19 and 19 'are locked, the output from the brake pressure reducing valve 46 to the brake hydraulic cylinder chamber 27 is in a stable state. Therefore, based on the detection value of the brake pressure sensor 50 when the power steering lever is tilted to the lock position, the control unit 4
9 selects a pressure characteristic, the brake pressure sensor 50
This makes it easy to compare with the detection result, and the selection of the hydraulic characteristics can be made accurately. The embodiments can be mutually selected and combined. According to the present invention, there is provided a position sensor 48 for detecting when a power steering lever provided in a driver's seat is tilted by a predetermined angle, and solenoids for left and right brake pressure reducing valves 46, 46 based on a signal from the position sensor 48. A control unit 49 for operating the solenoid 47 is set in advance with several types of pressure characteristics for operating the solenoid 47, and the control unit 49 includes a brake provided on the lower side of the brake pressure reducing valves 46, 46. Based on the oil pressure detection value measured by the pressure sensor 50, it is determined that the selection of the pressure characteristic is appropriate or not, and the control device controls the brake of the traveling device. detection result based on the pressure-force characteristic control unit 49 that is set in advance, which is measured by the brake pressure sensor 50 Chi, optimum pressure characteristics in order to obtain a set pressure for the tilting operation of the power steering lever after hydraulic change can be selected, therefore, the output of the brake pressure reducing valve 46 corresponding to the power steering lever tilting operation angle set pressure Thus, the turning can be performed in the same manner without changing the braking force of the brake with respect to the operation of the power steering lever, and the operational feeling and the actual running can be matched. Therefore, it is possible to stabilize, assure, and facilitate the brake control, thereby improving the operability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic longitudinal sectional view of a transmission case in an unfolded state. FIG. 2 is a sectional view. FIG. 3 is a hydraulic circuit diagram. FIG. 4 is a circuit diagram. FIG. 5 is an explanatory diagram showing hydraulic characteristics set in a control unit. FIG. 6 is a chart diagram. FIG. 7 is a chart diagram. FIG. 8 is an explanatory diagram. FIG. 9 is an explanatory diagram of an output state. FIG. 10 is a chart. FIG. 11 is an explanatory diagram of an output state. [Explanation of Signs] 1 ... mission case, 2 ... input shaft, 3 ... transmission, 4
... Large gear, 5 ... Small gear, 6 ... Speed increasing clutch, 7 ... Intermediate shaft, 8 ... Small gear, 9 ... Large gear, 10 ... Transmission gear, 11 ...
Sub transmission shaft, 12: small gear, 13: large gear, 14: transmission gear, 15: transmission member, 16: drive gear, 17: passive gear, 18: side clutch shaft, 19, 19 ': left and right brake, 22, 22 '... left and right rotating drum, 23, 23' ...
Left and right clutches, 24: Partition member, 25: Inner cylinder, 26
... Outer cylinder part, 27 ... Hydraulic cylinder chamber for brake, 28 ...
Piston, 29 ... rotating disk, 30 ... fixed disk,
31 ... Cylinder chamber for clutch engagement, 32 ... Cylinder chamber for clutch release, 33 ... Piston, 36 ... Side clutch gear, 37, 37 '... Reduction shaft, 38 ... Mode selection shaft, 39 ... Mode selection clutch, 40 ... Mode switching axis,
41: a gear for spin mode, 42: a gear for gentle turning mode, 43: sliding gear, 44: shifter, 45: left and right clutch switching valve, 46: left and right brake pressure reducing valve, 47: solenoid, 48: power steering lever position sensor , 49
... Control unit, 50 ... Brake pressure sensor.

Claims (1)

(57) Claims 1. A position sensor 48 that detects when a power steering lever provided in a driver's seat is tilted by a predetermined angle, and a left and right brake pressure reducing valve 46 based on a signal from the position sensor 48. , 46 having a control unit 49 for operating the solenoid 47, the control unit 49 is preset with several kinds of pressure characteristics for operating the solenoid 47, and the control unit 49 is provided on the lower side of the brake pressure reducing valves 46, 46. based on the hydraulic pressure detected value measured by the brake pressure sensor 50 provided in the control device of the brake arrangement the travel device to determine and re-controls the appropriateness of the selection of said pressure characteristics.