JP3731851B2 - Travel braking device in construction machinery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of travel braking devices for construction machines such as asphalt finishers.
[0002]
[Prior art]
In general, some of the traveling devices of this type of construction machine are provided with a high and low speed transmission mechanism that switches between high and low speed gears by a mechanical shifter mechanism. This is done by switching to a gear for low speed and a gear for low speed. When such a mechanical high / low speed traveling shift is performed, it goes through a so-called neutral state in which the gear engagement is released. However, when the traveling shift is performed on a slope such as a slope, the neutral It is assumed that the aircraft will run free by entering the state, and the aircraft will start running carelessly.
Therefore, conventionally, for example, as disclosed in Japanese Patent Application Laid-Open No. 63-162355, a detection switch for detecting a neutral position is provided, and in consideration of the brake detection in conjunction with the neutral detection, an inadvertent start is made. Are known.
[0003]
[Problems to be solved by the invention]
However, in the conventional system, when the high and low side travel shift is performed, the brake braking is automatically operated by detecting the neutral in the middle, so that the shifter gear serving as the lower side drive system of the high and low speed transmission mechanism is in the brake locked state. Therefore, the shifter gear in the brake lock state must be meshed with the transmission gear of the upper-side traveling drive system that is rotating by receiving the driving force, and for that purpose, at the moment when both gears are in meshing state. It is necessary to shift gears to engage the gears, but this operation is very difficult and not only causes tooth skipping, but also automatically releases the brakes in conjunction with the transition from the neutral state to the gear engagement state. There is a problem that the structure must be complicated for this purpose.
In addition, the conventional system detects neutral even when switching on a flat road where there is no worry of inadvertent driving, not only on slopes, but brake braking works each time. There is a concern that the operation frequency of brake braking will increase and the life of various parts such as electrical parts such as detection switches and relays, hydraulic parts and brake operating parts will be shortened, and this is the problem to be solved by the present invention. .
[0004]
[Means for Solving the Problems]
The present invention has been created in view of the above-described circumstances and has been created for the purpose of solving these problems, and the invention of claim 1 is a neutral drive gear transmission being released as a transmission device for a traveling drive system. In a construction machine having a high / low speed transmission mechanism for switching between high / low speed gear meshing across a state, the upper / lower side of the driving drive system of the upper / lower side of the high / low speed transmission mechanism may be While the upper side and lower side detection means for detecting the rotational speed or the rotational speed of the side traveling drive system are provided, respectively, when the ratio of the detected values is not a preset value or range in the traveling drive system given braking for traveling, when in the case of the set value or set range Ru provided a brake control means is controlled to the brake release for traveling, the braking control means running stop command is output When the travel stop command detection means for detecting whether or not the vehicle is in a state is connected and the travel stop command detection state is detected, the lower side detection means applies braking to the travel when the travel detection state is detected. This is a travel braking device in a construction machine that is controlled to release braking for travel when the side detection means is in a stop detection state . In this way, the problem is solved by applying braking only when the aircraft is truly inadvertently traveling, and inadvertent traveling in the state where the traveling stop command is output. In some cases, braking can be reliably applied .
According to a second aspect of the present invention, in the first aspect, the braking control means is configured such that the main driving tool for turning on the power is connected to the electric circuit of the driving system, and the main driving tool is in the OFF state. Is a traveling braking device for a construction machine, which is controlled so as to apply braking to traveling and to release braking for traveling in the ON state. In such a case, the driving main operation tool is turned off so that the braking state is maintained when the operator does not intend to travel, and when the traveling intention is not intended, the high / low speed transmission mechanism is neutral. It is designed to avoid inadvertent running of the aircraft even when it is in a state.
According to a third aspect of the present invention, in the first or second aspect, the braking control means is provided in a brake device that performs a braking operation by receiving pressure oil supplied from the hydraulic pump, and an oil path from the hydraulic pump to the brake device. An electromagnetic switching valve and a braking control unit for controlling power supply to a solenoid provided in the electromagnetic switching valve are provided. When the solenoid exciting current is supplied by a command from the braking control unit, the electromagnetic switching valve The road braking device for a construction machine is characterized in that the road is opened and the oil path is closed when the road is not supplied. And by doing in this way, certainty can be improved by using the control for applying braking as a negative theory.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a main body of a wheel type asphalt finisher. The main body 1 is provided at a driver's seat 2 for an operator to perform a driving operation and a front portion of the driver's seat 2 and an asphalt composite material is dumped. A hopper 3 fed from a truck, a screw spreader 4 for uniformly spreading the mixed material conveyed rearward from the hopper 3 through a bar feeder (not shown) to a paving width, a rear portion of the screw spreader 4, As in the conventional art, the screed 5 is composed of various member devices such as a screed 5, a two-wheel front wheel (driven wheel) 6, and a rear wheel (drive wheel) 7 described later.
[0006]
FIG. 2 shows a power transmission mechanism for the rear wheel 7. Pressure oil from a main hydraulic pump 9 driven by the drive of the engine 8 is supplied to a hydraulic motor 11 via a pipe 10, and hydraulic pressure based thereon As the motor 11 is driven, the drive gear 13 disposed in the transmission case 12 is driven to rotate together with the drive shaft 13a. A first intermediate shaft 14, a second intermediate shaft 15, and an output shaft 16 are rotatably supported on the transmission case 12. The first intermediate shaft 14 is a driven gear that is always meshed with the drive gear 13. 17 and high and low speed transmission gears 18 and 19 having different diameters are provided in a fixed state. The second intermediate shaft 15 is configured using a spline shaft, and a shifter gear 20 that is spline-fitted to the second intermediate shaft 15 so as to be movable in the axial direction and restricted in rotation around the axis. An intermediate gear 21 that is in a fixed state is provided.
[0007]
The shifter gear 20 is engraved with small and large gear teeth 20a, 20b that selectively mesh with the high and low speed transmission gears 18, 19, and is formed between the gear teeth 20a, 20b. The tip of the shifter 22 is engaged with the shifter groove 20c. The shifter 22 is provided in a fixed state on a shifter shaft 23 provided in the transmission case 12 so as to be axially movable. The shifter shaft 23 is provided with a detent mechanism 24 including a ball 24a on one end side thereof and a bullet machine 24b for urging the ball 24a. The shifter 22 is connected to a switching lever (switching operation tool) 25 through an interlocking mechanism (not shown), and the shifter 22 moves in the axial direction in conjunction with the switching operation of the high / low speed switching lever 25 by the operator. The small and large diameter gear teeth 20a and 20b are selectively engaged with the transmission gears 18 and 19 across the neutral position where the gear is not meshed. Thus, the high and low speed transmission mechanism of the present invention is implemented. Incidentally, the position movement of the shifter shaft 23 to the respective shift positions can be confirmed by fitting the balls 24a of the detent mechanism 24 into the shift position confirmation grooves 23a formed on the shifter shaft 23.
[0008]
On the other hand, the output shaft 16 is provided with a differential mechanism (differential mechanism) 26 having a final gear 26a in which a fixed intermediate gear 21 meshes with the second intermediate shaft 15, and the second intermediate shaft 15 is When the speed change rotation is performed, the rotation is transmitted to the output shaft 16 via the differential mechanism 26, and this is configured to transmit power to the rear wheel 7 via the chain transmission mechanism 27 that transmits power in the decelerated state. ing. Further, the main braking disk 28 is provided on the output shaft 16, and the main braking disk 28 is braked by the operation of the main braking mechanism 29 in conjunction with the stepping operation of the foot pedal 29 a provided in the driver's seat 2. In response, the output shaft 16 is set to be braked.
[0009]
The second intermediate shaft 15 is provided with a parking brake 30 and an auxiliary braking disk 31. The parking brake 30 is provided with a parking brake lever (operating tool) (not shown) provided near the driver's seat 2. ), And the sub-braking disc 31 is braked by the actuation of a hydraulic sub-braking mechanism 33 that operates based on a control command from a braking control unit 32 described later. In response to this, the second intermediate shaft 15 is braked. That is, the auxiliary braking mechanism 33 is operated by pressure oil supplied from the auxiliary hydraulic pump 34 that has been driven by the engine, but an electromagnetic switching valve 36 is provided in the oil passage from the auxiliary hydraulic pump 34 to the auxiliary braking mechanism 33. . When there is no command (excitation current supply) from the brake control unit 32, the electromagnetic switching valve 36 is stored to close the oil passage from the sub hydraulic pump 34. In this state, the sub brake mechanism 33 operates in the oil tank. The unloading state communicates with 34a, whereby the braking state is established and the rotation of the second intermediate shaft 15 is restricted. On the other hand, the solenoid 36a is excited by receiving a command from a braking control unit 32, which will be described later, and the valve path is switched against the stored power to open the oil path from the auxiliary hydraulic pump 34 while the oil is opened. The oil passage to the tank 34a is closed, whereby the auxiliary braking mechanism 33 is set to be supplied with pressure oil and switched to the non-braking state so that the rotation of the second intermediate shaft 15 is free.
[0010]
Further, this includes a travel main switch 37 for supplying power to the travel drive system, a start / stop switch 38 for powering on the main hydraulic pump 9, and an amount of current supplied to the main hydraulic pump 9. An accelerator lever (accelerator dial) 39 for increasing / decreasing is provided. For traveling of the airframe 1, it is necessary to turn on the traveling main switch 39, to operate the high / low speed shift lever 25, and to switch the start / stop switch 37 to the start position. When the lever 39 is set to the travel stop command position (non-acceleration position), the pressure oil supply amount to the hydraulic motor 11 of the main hydraulic pump 9 is not an amount sufficient to travel the airframe, so that the stop state is entered. In this stopped state, by operating the accelerator lever 39 to the speed increasing side, the amount of pressure oil supplied to the hydraulic motor 11 of the main hydraulic pump 9 is increased and the vehicle is traveling.
[0011]
The braking control unit 32 includes a drive-side detection sensor (input-side detection sensor) 40 that detects the rotation speed (or rotation speed detection) of the drive gear 13 and a rotation speed detection (or rotation speed detection) of the final gear 26a. The output side detection sensor 41 is connected to each other, and the travel main switch 37, the start / stop switch 38, and the accelerator lever 39 are connected to each other. The braking control unit 32 is configured to perform a control operation according to the following system flow. In other words, the braking control unit 32 starts the system when the power is turned on by turning on a key switch (not shown), reads necessary data, and is initialized. In this state, it is determined whether or not the traveling main switch 37 is operated to the ON side (traveling side). When the traveling main switch 37 is in the OFF side, an operation command output (excitation current) to the solenoid 36a is determined. Output) is OFF (braking command output). As a result, the electromagnetic switching valve 36 closes the valve path, and the auxiliary braking mechanism 33 is maintained in the braking state to restrict the rotation of the second intermediate shaft 15. .
[0012]
On the other hand, when the travel main switch 37 is operated to the ON side, whether the start / stop switch 38 is operated to the start position or the stop position, whether the accelerator lever 39 is in the non-acceleration position (stop) It is determined whether the vehicle is operated to the position) or the acceleration position (traveling position). Even if the start / stop switch 38 is operated to the start position, if the accelerator lever 39 is operated to the non-acceleration position (stop position), it is determined that the travel stop command is being output. Then, it is determined whether or not the rotation speed detection value Y from the output side detection sensor 41 is zero (Y = 0), that is, whether or not the vehicle is traveling (stopped). In this case, control is performed to output a non-braking command (excitation current output) to the solenoid 36a, the solenoid 36a is excited, the electromagnetic switching valve 36 is switched, and the valve path is opened. The braking mechanism 33 is in a non-braking state and the second intermediate shaft 15 is free to rotate. On the other hand, when it is determined that the rotation speed detection value Y from the output side detection sensor 41 is not zero (Y ≠ 0), a braking command (stop of excitation current output) is output to the solenoid 36a. As a result, the electromagnetic switching valve 36 enters a braking state. Incidentally, in the present invention, instead of detecting the operation position of the accelerator lever 39, the travel stop command output state can be detected by determining that the detection value of the input side detection sensor 40 is zero. Of course, the travel stop command detection means may be set in this way.
[0013]
On the other hand, when it is determined that the accelerator lever 39 is set at the acceleration position, that is, when it is determined that the vehicle is traveling, the rotational speed detection value Y of the output side detection sensor 41 and the drive side detection sensor 40 are detected. The ratio (X / Y) of the rotation speed detection value X is calculated, and the obtained value (X / Y) is set in advance as a ratio (normal value) or a set range ( In the case where it is determined whether it is a set value (setting range), if the non-braking command is determined not to be a setting value (setting range) The braking command described above is set to be output to the solenoid 36a.
[0014]
In the structure constructed as described, the vehicle 1 travels when the travel main switch 37 is turned on, the start / stop switch 38 is switched to the start side, and the high / low speed switching lever 25 is shifted from the neutral position to either the high speed or the low speed. The operation is performed by operating the accelerator lever 39 from the stop position to the speed increasing side in the state of being operated to the position. When shifting such a body travel to a high or low side, the main brake mechanism 29 is operated by depressing the foot pedal 29a, and the accelerator lever 39 is returned to the stop position, and the travel is stopped. In this operation state, when the output side detection sensor 41 is detected as being in the travel stop state, it is normal, and therefore, the sub braking mechanism 33 is controlled in the non-braking state. As a result, when shifting the high / low speed switching lever 25 beyond the neutral position, the shifter gear 20 on the lower side of the high / low speed transmission mechanism is engaged with either of the high / low speed transmission gears 18, 19. Since the shifter gear 20 is in a non-braking state, the shifter gear 20 has a degree of freedom of rotation compared to the conventional case where the neutral state is detected and braked and fixed. The shifter gear 20 can be rotated after being in the aligned state, the gear meshing property is improved, and the occurrence of the tooth skip phenomenon can be reduced. On the other hand, if the travel is detected in the operation state when the travel shift is performed, this is abnormal, so the subbraking mechanism 33 is switched to the braking state, and the inadvertent travel of the body 1 is avoided.
[0015]
Further, when it is determined that the ratio (X / Y) of the detection values of the input / output side detection sensors 40 and 41 is not a normal value in the airframe traveling state, the gear meshing of the shifter gear 20 with respect to the high and low speed transmission gears 18 and 19 is This means that it has been inadvertently disengaged for some reason (for example, when the high / low speed switching lever 25 is unintentionally touched and set to the neutral position). The mechanism 33 is switched to the braking state, and inadvertent traveling of the airframe 1 is avoided. As described above, in the embodiment in which the present invention is implemented, the auxiliary braking mechanism 33 is automatically activated only when braking is really necessary such as inadvertent traveling because it happened to be an inclined place at the time of traveling speed change. Therefore, the auxiliary brake mechanism 33 is operated less frequently, and frequent detection or the like is not required every time the conventional neutral detection sensor is switched, and electrical components such as a detection switch and a relay are provided. There is an advantage that the life of various parts such as hydraulic parts and brake operating parts can be extended.
[0016]
In addition, in this case, when the traveling main switch 37 is turned off, the auxiliary braking mechanism 33 is controlled to be in a braking state, so that inadvertent aircraft traveling is avoided. -Switching to non-braking is configured such that the control command output from the braking control unit 32 is in a braking state when the solenoid 26a is not excited and is in a non-braking state when the solenoid 26a is excited. As a result, the braking operation of the auxiliary braking mechanism 33 is a negative theory, that is, the output is stopped when braking is performed, and the output is performed when braking is not performed. In other words, when the operator does not intend to travel, in other words, the traveling main When the switch 37 is OFF or the engine is stopped, the braking state without the excitation of the solenoid 26a results in a high / low speed shift lever. Body 1 also is set to the neutral position 25 it is reliably is improved without the inadvertent driving.
[0017]
Furthermore, the traveling stop command output Sometimes abnormal or aircraft traveling not there, because they were the normal decision, when traveling stop command output, non (X / Y) is the input-output-side detection sensor 40 and 41 Even in an abnormal case where the vehicle runs at a high speed / low speed gear change ratio, it is convenient to be able to brake reliably.
The input / output detection sensor is not limited to the above-described embodiment as long as it can detect the rotation (travel) of the upper and lower sides of the high / low speed switching mechanism provided in the travel drive system. Obviously it is.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an asphalt finisher.
FIG. 2 is a system diagram showing a travel drive system.
FIG. 3 is a system diagram of a high / low speed switching mechanism.
FIG. 4 is a block circuit diagram showing a braking control mechanism.
FIG. 5 is a flowchart showing a braking control state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Airframe main body 9 Main hydraulic pump 11 Hydraulic motor 12 Transmission case 18 High speed transmission gear 19 Low speed transmission gear 20 Shifter gear 32 Drive control part 33 Sub brake mechanism 34 Sub hydraulic pump 36 Electromagnetic switching valve 36a Solenoid 37 Traveling main switch 38 Start / Stop switch 39 Accelerator lever 40 Drive side detection sensor 41 Output side detection sensor

Claims (3)

In a construction machine comprising a high / low speed transmission mechanism that switches between high / low speed gear meshing across a neutral state where gear meshing is released as a traveling drive transmission, the upper side of the high / low speed transmission mechanism The driving system for the lower side is provided with upper side and lower side detection means for detecting the rotational speed or rotational speed of each upper side and lower side driving system, while the driving system for the lower side is provided with the above detection. Upon giving braking for traveling when the ratio of the value is not the value or range is set in advance, Ru provided a brake control means is controlled to the brake release for traveling when a set value or the set range, the The braking control means is connected to a travel stop command detection means for detecting whether or not a travel stop command is being output, and when it is in the travel stop command detection state, the lower side detection means Traveling given braking the running when detecting a state, when the downstream side detection means is a stop detection state is intended to be controlled to the brake release for traveling the traveling brake system in the construction machine.   The braking control means according to claim 1, wherein a traveling main operation tool for turning on power is connected to an electric circuit of the traveling drive system, and braking is performed for traveling when the traveling main operation tool is in an OFF state. And a braking device for a construction machine that is controlled to release braking for traveling in the ON state.   3. The braking control means according to claim 1, wherein the braking control means includes a brake device that receives a pressure oil supply from the hydraulic pump and performs a braking operation, an electromagnetic switching valve provided in an oil passage from the hydraulic pump to the brake device, and the electromagnetic switching valve. The electromagnetic switching valve opens the oil passage from the hydraulic pump when the solenoid exciting current is supplied in response to a command from the braking control unit. A traveling braking device for a construction machine, characterized in that it is set to close an oil passage when not.

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