JPH10325454A - Running drive device for construction vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a running drive device of a construction vehicle to abolish a brake device, effect brake by double-engaging clutches for a high speed and a low speed, and be compacted, and facilitate manufacture. SOLUTION: A running drive device for a construction vehicle having a planetary reduction gear comprises a high speed clutch 40 coupled on the same core as that of the output shaft of a hydraulic motor 2 and between the output shaft 2 and a carrier 13, and connect and disconnect a power to a carrier 13; a low speed clutch 41 coupled on the same core as that of the high speed clutch between the output shaft of the hydraulic motor 2 and the carrier 13 and connecting and disconnecting a power to the carrier 13; and a first control means to bring the high and low speed clutches 40 and 41 into a simultaneous engaging state and apply brake on a vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling drive system using a planetary gear reducer of a construction vehicle, and more particularly to an arrangement of a high-speed clutch and a low-speed clutch incorporated in a planetary gear reducer by eliminating a brake device. The present invention relates to a traveling drive device for a construction vehicle in which an improvement and a control method thereof are improved.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional traveling drive device using a planetary gear reducer for driving tracks or wheels of a construction vehicle.
This will be described with reference to FIGS. FIG. 13 is a side sectional view of a two-stage planetary gear reducer, and FIG. 14 is a skeleton diagram thereof. As shown in one example of the traveling drive device of the construction vehicle in FIGS. 13 and 14, a variable displacement hydraulic motor 80 is provided in the case 1. The variable displacement hydraulic motor 80 includes a speed switching regulator valve (not shown), a counterbalance valve for preventing overrun, a safety valve, and a multi-plate parking brake device 81 which are not shown. The output shaft 82 of the variable displacement hydraulic motor 80 has a first planetary gear reducer 1
The first sun gear 16 of 0 is fixed. The first sun gear 16 meshes with the first planetary gear 12. The first planetary gear 12 meshes with a ring gear 6 fixed to a drum 5 rotatably attached to the case 1 via a bearing 4 via a bearing 4. The first carrier 13 that supports the first planetary gear 12 is the second sun gear 21 of the second planetary gear reducer 20.
Is engaged. The second sun gear 21 meshes with a second planetary gear 22 rotatably attached to a pin 83 fixed to the case 1. The second planetary gear 22 meshes with the ring gear 6. The ring gear 6 is fixed to the drum 5. A sprocket 7 is provided on the outer periphery of the drum 5.
Is fixed.

A traveling drive device shown in FIGS. 13 and 14 for driving a crawler belt or wheels of a construction vehicle drives the first sun gear 16 by the output rotation of a variable displacement hydraulic motor 80. The rotation of the first sun gear 16 causes the first
Power is transmitted from the planetary gear reducer 10 to the second planetary gear reducer, and the sprocket 7 is driven by being reduced in two stages. When a brake is applied to the traveling drive device using the planetary gear reducer, a hydraulic brake (not shown) (generally, the traveling valve is set to a neutral position and the supply of pressure oil to the traveling motor is stopped) is used. . When the vehicle overruns, for example, when descending a hill, a counter balance valve (not shown) is activated to activate a hydraulic brake to prevent this. At the time of parking, the multi-plate parking brake device 81 is operated.

Next, FIG. 15 is a side sectional view of a two-stage planetary reducer using a spur gear and a planetary gear reducer, and FIG. 16 is a skeleton diagram thereof. As shown in FIGS. 15 and 16, a variable displacement hydraulic motor 80 is provided with a speed switching regulator valve, a counterbalance valve, and a safety valve (not shown), and an output shaft 82 of the variable displacement hydraulic motor 80. Is provided with a multi-plate parking brake device 81. Further, a reduction pinion 91 of the spur gear 90 is fixedly provided at the tip of the output shaft 82. This deceleration pinion 91 meshes with a deceleration gear 92 rotatably attached to the case 1. The sun gear 94 of the planetary gear reducer 93 connected to the reduction gear 92 meshes with the planetary gear 95. Planetary Gya 95 is Case 1
Is engaged with a ring gear 96 fixedly mounted on the ring gear 96. The sprocket 7 is fixed to a carrier 97 that supports the planetary gear 95 via a drive shaft 98.

In the traveling drive system for a construction vehicle shown in FIGS. 15 and 16, the power generated by the output rotation of the variable displacement hydraulic motor 80 is reduced by a spur gear 90, and the reduced power is further reduced by a planetary gear reducer 93. Output after deceleration.
When a brake is applied to the traveling drive device using the planetary gear reducer, a hydraulic brake (not shown) is used. Overrun of the vehicle is prevented by the counterbalance valve. At the time of parking, the multi-plate parking brake device 81 is operated.

Japanese Patent Application Laid-Open No. 53-129768 has been filed as an example of the prior art of a power transmission device using a planetary gear reducer. This application consists of a fixed frame,
An input device, an output device, and first and second planetary gear assemblies, each of the assemblies having a carrier having at least one sun gear, a ring gear, and a planetary gear; The reversible speed-variation connecting the ring gear of the second planetary gear assembly to and via the carrier of the second planetary gear assembly to the output device and the input device to the first sun gear. Module, and a brake device for releasably connecting the carrier of the first planetary gear assembly to the frame, wherein when the brake device is engaged, the output device is connected to the speed-change module by the input device. A first releasable clutch device (high) for driving via a first planetary gear assembly and for coupling a carrier of the first planetary gear assembly to the input device. And use), the second second releasable clutch device the planetary gear assembly of the sun gear is connected to the input device (power transmission device characterized by comprising a low-speed), is described. That is, a brake device for releasably connecting the carrier of the first planetary planetary gear assembly to the frame, a first releasable clutch device (for high speed), and a second releasable clutch device (for low speed) There is a structure with.

Japanese Patent Application Laid-Open No. 7-174209 has been filed as two prior art examples of a power transmission device using a planetary gear reducer. This application discloses two independent variable displacement hydraulic pumps driven from one input shaft via a transfer, two variable displacement hydraulic motors respectively connected to the two via oil passages, Gears, a first-stage planetary gear unit, a second-stage planetary gear unit, two shift-stage switching clutches for low-speed and high-speed stages, and a wet-type built-in brake, The variable displacement hydraulic motor and the final reducer are of the same type arranged on the left and right, and the output shaft of the variable displacement hydraulic motor is connected to a gear reduction device in the final reducer. A technique characterized by the following is described. This prior art is also configured similarly to the above, including two shift speed switching clutches for a low speed stage and a high speed stage, and a wet built-in type brake.

[0008]

However, FIG.
In the traveling drive device using the planetary gear reducer shown in FIG. 16 to FIG. 16, when the traveling speed is changed from low speed to high speed, the swash plate angle of the variable displacement hydraulic motor is increased or decreased. Since a motor is required, the cost is high, and the speed range in which the traveling speed is controlled from low to high by controlling the swash plate angle is also limited. In addition, various valves such as a counterbalance valve are required, and a dedicated brake device is required for parking or the like, so that there is a problem that the structure is complicated.

The power transmissions described in the above-mentioned JP-A-53-129768 and JP-A-7-174209 are both provided with a high-speed and low-speed clutch and a brake device, so that the structure is complicated. There is a problem that it cannot be made compact.

The present invention focuses on the above-mentioned problems of the prior art, and disposes a high-speed and low-speed clutch with a simple structure in a traveling drive device using a planetary gear reducer that drives a track or a wheel of a construction vehicle. In addition, the present invention provides a traveling drive device for a construction vehicle that is compact and easy to manufacture by eliminating a brake device as in the conventional art and enabling braking by double-engaging a high-speed and low-speed clutch. With the goal.

[0011]

In order to achieve the above object, a first invention of a traveling drive device for a construction vehicle according to the present invention receives supply of pressure oil from a hydraulic pump driven by an engine. A hydraulic motor, a planetary gear reducer connected to an output shaft of the hydraulic motor, and a traveling drive device of a construction vehicle for driving power from the planetary gear reducer through a gear reducer to drive a sprocket. 2 is disposed between the hydraulic motor 2 and the carrier 13 of the planetary gear reducer, coaxially with the output shaft of the hydraulic motor 2 and when the output shaft of the hydraulic motor 2 and the carrier 13 are in the engaged state. A high-speed clutch 40 for transmitting the driving force of the high-speed rotation to the gear reducer via the carrier 13 of the planetary gear reducer, and the hydraulic motor 2 and the planetary gear reducer The planetary gear 12 is disposed between the planetary gear 12 and the ring gear 11 of the planetary gear reducer, and the planetary gear 12 meshes with the sun gear 15 when the hydraulic motor 2 is in the engaged state with the sun gear 15. And a first control means for simultaneously engaging the high-speed clutch 40 and the low-speed clutch 41 to bring the vehicle to a stop state. . According to the above configuration, the vehicle can travel at high speed by setting the high speed clutch 40 to the engaged state, and can run at low speed by setting the low speed clutch 41 to the engaged state. The low-speed clutch 41 is double-engaged to act as a brake. For this reason, according to the present invention,
It is not necessary to incorporate a brake device as described in Japanese Patent Application Laid-Open No. 9768 and Japanese Patent Application Laid-Open No. 7-174209.
Therefore, the traveling drive device incorporating the planetary gear reducer can be made compact and the cost can be reduced.

According to a second aspect of the present invention, there is provided a hydraulic motor driven by receiving a supply of pressure oil from a hydraulic pump driven by an engine, and a first motor rotatably driven by an output shaft of the hydraulic motor.
A first stage planetary gear reducer including a sun gear, a first planetary gear meshed with the first sun gear and supported by the first carrier and meshed with the first ring gear, and a first gear driven by an output shaft of a hydraulic motor. A second stage planetary gear reducer including a second sun gear and a second planetary gear engaged with the second carrier and supported by the second carrier and meshed with the second ring gear engaged with the first carrier. In a traveling drive device of a construction vehicle in which a planetary gear reducer is disposed and a sprocket is driven by rotation of a second ring gear,
A first-stage planetary gear reducer and a second-stage planetary gear reducer are arranged in parallel, and a high-speed clutch 40 for connecting and disconnecting power to the first carrier 13, and for connecting and disconnecting power to the second carrier 23. The low-speed clutch 41 to be performed is coaxially arranged in parallel, and a first control means for controlling the high-speed clutch 40 and / or the low-speed clutch 41 to an engaged state is provided. According to the above configuration, as shown in FIG. 3, the traveling drive device can shorten the L dimension in the longitudinal direction. In addition, by driving the high-speed clutch 40 in the engaged state, the vehicle can travel at high speed, and by engaging the low-speed clutch 41 in the engaged state, the vehicle can travel at low speed.
When the vehicle is stopped, the high-speed clutch 40 and the low-speed clutch 41 are double-engaged to function as a brake. For this reason, according to the present invention, JP-A-53-129768 and JP-A-7-174 are disclosed.
There is no need to incorporate a brake device as described in No. 209. Therefore, the traveling drive device incorporating the planetary gear reducer can be made compact and the cost can be reduced.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the first control means includes a high / low speed changeover switch 7 for switching between a high speed position, a low speed position and a neutral position.
0, high-speed solenoid valve 7 connected in parallel with the pilot pump
1 and a low-speed solenoid valve 72, and a high-low switching valve 7 having one connected to the high-speed solenoid valve 71 and the low-speed solenoid valve 72 and the other connected to the high-speed clutch 40 and the low-speed clutch 41.
3 and outputs a command to the high-speed solenoid valve 71 to engage the high-speed clutch 40 when the high-low speed switch 70 is in the high-speed position and to run at high speed. When the high / low speed switch 70 is in the neutral position, the high speed clutch 40 and the low speed clutch 41 are simultaneously engaged to output a command to the low speed solenoid valve 72 to engage the vehicle at low speed. High-speed solenoid valve 71 and low-speed solenoid valve 72 to apply braking
And a controller 63 that does not output a command to the controller 63. According to the above configuration, when the high / low speed changeover switch 70 is set to the neutral position, the high speed clutch 40 and the low speed clutch 41 are simultaneously engaged to apply braking to the vehicle so that the high speed solenoid valve 71 and the low speed solenoid valve 72 are engaged.
The controller 63 does not output a command. Therefore, the high-speed solenoid valve 71 and the low-speed solenoid valve 72
Is in the closed position, and the high / low speed switching valve 73 is not operated and is in the neutral position. Therefore, the pilot pressure from the pilot pump does not act on the high speed clutch 40 and the low speed clutch 41. Thus, the high-speed clutch 40 and the low-speed clutch 41 can be simultaneously engaged to brake the vehicle. This constitutes a so-called negative brake. Therefore, in addition to the effects of the first and second inventions, when the pilot pressure does not act on the high / low speed switching valve 73, the vehicle can be braked. Since the control circuit of the low-speed clutch 41 is simply configured, manufacture is easy.

According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, there is provided a first detecting means 66 for detecting an overrun rotation of the engine. When the engine speed exceeds a set value based on the calculation result, the high-speed clutch 40 and the low-speed clutch 41 are double-engaged to stop the vehicle. Low speed switching valve 7
3 is provided with a controller 63 that does not output a command signal. According to the above configuration, the overrun rotation of the engine is detected in advance, and the high-speed clutch 40 and the low-speed clutch 41 are simultaneously double-engaged, thereby braking the vehicle and automatically preventing overrun.
Therefore, it is possible to drive safely even when the vehicle is going downhill, and it is particularly useful for a road or a construction vehicle during land preparation work.

According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, a first detecting means 66 for detecting a stop state of the engine is provided. When the engine speed is less than a set value based on the calculation result, the high-speed clutch 40 and the low-speed clutch 41 are double-engaged to stop the vehicle at a low speed. The configuration includes a controller 63 that does not output a command signal to the switching valve 73. According to the above configuration, by turning off the engine key switch when the vehicle is parked, the high-speed clutch 40 and the low-speed clutch 41 can be simultaneously double-engaged and the vehicle can be automatically stopped. Thus, as described above, there is no need to provide a brake device in addition to the high-speed clutch 40 and the low-speed clutch 41 unlike the conventional structure. Therefore, only by turning off the engine key switch, the vehicle can be safely parked, and the structure is simple and the manufacturing cost is low.

According to a sixth aspect of the present invention, in the configuration according to any one of the first to fifth aspects, a second detecting means 65 for detecting a traveling oil pressure of the hydraulic motor 2 is provided. The high speed clutch 40 is engaged when the calculated value is equal to or less than the set value of the traveling oil pressure stored in advance based on the result of the calculation, or the calculated result is equal to or greater than the set value of the travel oil pressure. In such a case, the controller 63 does not output a command signal to the high / low speed switching valve 73 so that the low speed clutch 41 is engaged.
According to the above configuration, the high-speed clutch 40 or the low-speed clutch 41 can be automatically engaged depending on the running load condition of the vehicle (a road surface having unevenness, a steep slope, a flat road, or the like), so that the running performance is improved. Is improved. Therefore, even if the traveling load condition differs depending on the work site, stable traveling can be performed, which is useful for a construction vehicle.

According to a seventh aspect of the present invention, in the configuration according to any one of the first to sixth aspects, a travel lever 64 for switching a travel solenoid valve 62 disposed between the hydraulic pump 61 and the hydraulic motor 2 is provided. Receiving the operation position signal of the traveling lever 64, the traveling electromagnetic valve 62 is set to the neutral position when the traveling lever 64 is in the neutral position, and the high-speed clutch 4
The controller 63 does not output a command signal to the high / low speed switching valve 73 so as to stop the vehicle by double-engaging the 0 and low speed clutch 41. According to the above configuration, by setting the traveling lever 64 to the neutral position, the high-speed clutch 40 and the low-speed clutch 41 can be simultaneously double-engaged to automatically stop the vehicle. Thus, as described above, there is no need to provide a brake device in addition to the high-speed clutch 40 and the low-speed clutch 41 unlike the conventional structure. Therefore, the vehicle can be safely parked only by setting the traveling lever to the neutral position, and the structure is simple and the manufacturing cost is low. According to the configuration in which the seventh invention is added to the fifth invention,
By simply turning off the engine key switch or setting the travel lever to the neutral position, the vehicle can be safely parked, which improves safety and is useful as a construction machine.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a construction driving apparatus for a construction vehicle according to an embodiment of the present invention; First, a first embodiment of a traveling drive device for a construction vehicle according to the present invention will be described with reference to FIGS. 1, 2, 7, and 8. FIG. FIG. 1 is a side sectional view of the traveling drive device, and FIG. 2 is a skeleton diagram thereof. FIG. 7 is a control circuit of the traveling drive device, and FIG. 8 is a schematic explanatory diagram of the control device. The main part of the first embodiment is to transmit power to a sprocket (drive wheel) via a high-speed clutch incorporated in a planetary gear reducer and a low-speed clutch for rotationally driving an output shaft of a hydraulic motor. The high-speed clutch and the low-speed clutch are controlled by a first control unit described later in detail, and
Alternatively, the low-speed clutch can be brought into the engaged state. The first embodiment requires a brake device in addition to the conventional high-speed clutch and low-speed clutch, and is disclosed in JP-A-53-129768 and JP-A-7-17.
The drive device described in No. 4209 was improved, and the brake device was abolished.
The purpose of the double engagement is to apply a brake to the vehicle to bring it into a stopped state. Hereinafter, the traveling drive device of the first embodiment will be described in order. A first ring gear 11 of a first planetary gear reducer 10 is fixed to an output shaft 3 of a fixed displacement hydraulic motor 2 fixed to a case 1 as shown in FIGS. First
A second sun gear 21 of a second planetary gear reducer 20 is provided at a distal end of a shaft 14 fixed to a first carrier 13 that supports a first planetary gear 12 that meshes with the ring gear 11. A high-speed clutch 40 is provided between the output shaft 3 and the first carrier 13, and the first planetary gear reducer 1
A low-speed clutch 41 is provided between the first sun gear 15 and the case 1. The high speed clutch 40 is a spring 42
As a result, the clutch 40 is disengaged (hereinafter, referred to as ON) by the pilot pressure acting on the clutch 40 (hereinafter, referred to as ON).
Say OFF. ). Further, the low-speed clutch 41 is engaged (hereinafter, referred to as ON) by the spring 43, and
Pilot pressure acts on the clutch 41 to bring it into a non-engaged state (hereinafter referred to as OFF). The second carrier 23 supporting the second planetary gear 22 meshing with the second sun gear 21 of the second planetary gear speed reducer 20 has the third sun gear 31 of the third planetary gear speed reducer 30 attached thereto. The third carrier 32 fixed to the first carrier 32
It is in mesh with the planetary gear 33. A drum 5 is rotatably mounted on an outer peripheral portion of the case 1 via a bearing 4, and a ring gear 6 provided on an inner periphery of the drum 5, a second planetary gear 22 of a second planetary gear reducer 20, and a third gear 5. The planetary gear reducer 30 is in mesh with the third planetary gear 33.
A sprocket 7 is attached to the outer periphery of the drum 5.

Next, the traveling drive device shown in FIGS. 1 and 2 will be described. (1) At low speed running The low speed clutch 41 is turned on and the high speed clutch 40 is turned off.
By driving the fixed displacement hydraulic motor 2,
The power is input to the first ring gear 11 of the first planetary gear reducer 10 via the output shaft 3. At this time, the first sanguya 1
Power is output from the first carrier 13 because 5 is fixed to the case 1. In this case, the reduction ratio i is i = 1 + ZS / ZR or (ZS + ZR) / ZR, where ZS is the number of teeth of the sun gear 15 and ZR is the number of teeth of the ring gear 11. The second planetary gear reducer 20 has a second sun gear 21. 13 and 14, and output to the sprocket 7 via a two-stage speed reducer constituted by a second planetary gear reducer 20 and a third planetary gear reducer 30 in the same manner as the conventional one described in FIGS. . (2) During high-speed running The high-speed clutch 40 is turned on and the low-speed clutch 41 is turned off.
The first ring gear 11 and the first sun gear 1
5 and the first carrier 13 are integrated, and the power of the fixed displacement hydraulic motor 2 is directly output to the second sun gear 21 of the second planetary gear reducer 20 and output to the sprocket 7 via the two-stage reduction gear. . (3) During braking, the high-speed clutch 40 and the low-speed clutch 41 are simultaneously turned on.
As a result, a double engagement state is established, which acts as a dynamic brake and brakes.

With the above configuration, the gear ratio can be increased as compared with the conventional traveling drive device.
Further, high-speed traveling is possible even if the rotation speed of the hydraulic motor is reduced, noise can be reduced, and a small fixed displacement hydraulic motor can be used, and the cost is low. Further, during either high-speed or low-speed traveling, the other clutch can be turned on to operate as a dynamic brake, and the braking feeling is improved. Furthermore, the high-speed clutch 40
When the hydraulic pressure is cut off while the engine is stopped, the low speed clutch 41 is urged by the springs 42 and 43, and both clutches 40 and 41 are turned on, and can be used as a parking brake, so that the safety is high. Note that the fixed displacement hydraulic motor 2 may be a variable displacement hydraulic motor. In this case, the speed range can be further expanded and the continuously variable transmission can be achieved.

Next, a control circuit diagram of the traveling drive device shown in FIGS. 7 and 8 will be described. A hydraulic pump 61 driven by the engine 60 is connected to the fixed displacement hydraulic motor 2 via a traveling solenoid valve 62. The traveling solenoid valve 62 has three positions: forward (F), neutral (N), and reverse (R).
It is connected to the controller 63. A traveling lever 64 for operating three positions of forward, neutral, and reverse is provided by a controller 63.
Is connected to The traveling lever 64 is shown as a hydraulic pilot type in the figure, but may be an electric lever using a known potentiometer instead. One of the operation directions of forward, neutral and reverse of the travel lever 64 is input to the controller 63, and the travel solenoid valve 62 is switched according to the operation direction. The opening of the traveling solenoid valve 62 is controlled in accordance with an operation signal (pilot pressure, operation angle, stroke, etc.) from the traveling lever 64,
The supply amount of the pressure oil discharged from the hydraulic pump 61 is adjusted,
Pressure oil is supplied to the hydraulic motor 2 to control the number of rotations of the motor 2.

A high / low speed switch 70, a high speed solenoid valve 71, and a low speed solenoid valve 72 having three positions, a high speed position, a low speed position, and a neutral position, are connected to the controller 63.
The operation signal from the high / low speed switch 70 is selected from the high speed position, the low speed position, and the neutral position.
And a command signal is output from the controller 63 to the high-speed solenoid valve 71 or the low-speed solenoid valve 72 in accordance with the operation signal, and is controlled. The high-speed solenoid valve 71 and the low-speed solenoid valve 72 have two positions, an open position and a closed position. The high-speed clutch 40 and the low-speed clutch 41 incorporated in the planetary gear reducer of the traveling drive device 50 are provided with a high-low speed switching valve 73,
It is connected to a pilot pump 74 via a high-speed solenoid valve 71 and a low-speed solenoid valve 72. The high / low speed switching valve 73 has three positions: a high speed position (a), a drain position (b), and a low speed position (c).
It has a position and is connected to the high-speed solenoid valve 71 and the low-speed solenoid valve 72 by pilot lines 75 and 75. Hydraulic pressure sensors 65, 65 are provided in the discharge pipeline of the hydraulic pump 61. The pressure signals from the oil pressure sensors 65, 65 are input to the controller. A rotation speed signal from an engine rotation speed detection sensor 66 for detecting the rotation speed of the engine 60 is input to the controller 63. 67 is an oil tank.

Next, FIGS. 7 and 8 will be described with reference to FIG. In the case of forward traveling, the traveling lever 64 is moved forward (F).
In this position, the traveling solenoid valve 62 is switched to the forward (F) position by a command signal from the controller 63, and the hydraulic motor 2 rotates in the forward direction. In the case of reverse travel, the controller 63 is set by moving the travel lever 64 to the reverse (R) position.
The traveling electromagnetic valve 62 is switched to the reverse (R) position in response to a command signal from the controller, and the hydraulic motor 2 rotates in the reverse direction. In the stop state, when the travel lever 64 is set to the neutral (N), no command signal is output from the controller 63, the travel solenoid valve 62 is set to the neutral (N) position, and the hydraulic line is shut off.
The rotation of the hydraulic motor 2 stops. Here, as described above, the high-speed clutch 40 and the low-speed clutch 41 are turned off (the clutch is disengaged) by the action of the pilot pressure, and
When the pilot pressure is not applied, the spring 4 shown in FIG.
It is configured to be pushed ON by 2 and 43 to be turned ON (clutch engagement state).

In the case of high-speed running, when the high-low speed switch 70 is set to the high-speed position, the controller 63 outputs a command signal for opening the high-speed solenoid valve 71. Therefore, the pilot pressure discharged from the pilot pump 74 acts on the high / low speed switching valve 73 via the high speed solenoid valve 71,
The switching valve 73 is switched to the high speed (a) position. As a result, the pilot pressure becomes high (a) of the high / low switching valve 73.
It acts on the low-speed clutch 41 from the position, and turns off the clutch 41. At this time, the high speed clutch 40 is in communication with the drain line via the high / low speed switching valve 73. For this reason, the pilot pressure acting on the high-speed clutch 40 is drained, and the clutch 40 is pushed by the spring 42 to be turned ON, so that the traveling drive device 50 is driven for high-speed traveling.

When the vehicle is traveling at a low speed, when the high / low speed changeover switch 70 is set to the low speed position, a command signal for opening the low speed solenoid valve 72 is output from the controller 63. For this reason, the pilot pressure discharged from the pilot pump 74 acts on the high / low speed switching valve 73 via the low speed solenoid valve 72,
The switching valve 73 is switched to the low speed (C) position. As a result, the pilot pressure becomes lower (C) of the high / low speed switching valve 73.
It acts on the high-speed clutch 40 from the position, and turns off the clutch 40. At this time, the low-speed clutch 41 is in communication with the drain pipe via the high-low speed switching valve 73. For this reason, the pilot pressure acting on the low-speed clutch 41 is drained, and the clutch 41 is pushed by the spring 43 to be turned on, and the traveling drive device 50 is driven for low-speed traveling.

When braking, the high / low switch 70
Is set to the neutral position, the controller 63 sends the high-speed solenoid valve 7
1 and no command signal to the low-speed solenoid valve 72 is output, so the high-low speed switching valve 73 is at the neutral position. Therefore, the pilot pressure acting on the high-speed clutch 40 and the low-speed clutch 41 is drained.
41 is pushed by the respective springs 42 and 43 to be in a double engagement state. As a result, the power output from the hydraulic motor 2 is not transmitted, and the vehicle enters a braking state. With the above configuration, the counterbalance valve, safety valve, and brake device for preventing overrun provided in the conventional hydraulic motor are not required, and the structure of the traveling drive device can be simplified.

Next, the operation of FIGS. 1, 2, 7 and 8 will be described. According to the first embodiment of the present invention, the high-speed clutch 4
0 can be driven at high speed, and the low speed clutch 41 can be driven at low speed when the low speed clutch 41 is engaged.
0 and the low-speed clutch 41 are simultaneously engaged in a double operation to act as a brake. Therefore, as described above, there is no need to incorporate a brake device as described in JP-A-53-129768 and JP-A-7-174209. As a result, the traveling drive device incorporating the planetary gear reducer can be made compact and the cost can be reduced.

When the high / low speed switch 70 is set to the neutral position, the high speed clutch 40 and the low speed clutch 4
1 to the high-speed solenoid valve 71 and the low-speed solenoid valve 72 to simultaneously engage the
Does not output any command. Accordingly, the high-speed solenoid valve 71 and the low-speed solenoid valve 72 are in the closed position, and the high-low speed switching valve 73 does not operate and is in the neutral position, so that the pilot pressure from the pilot pump 74 is applied to the high-speed clutch 40 and the low-speed clutch. Does not act on 41. Thus, the high-speed clutch 40 and the low-speed clutch 41 can be simultaneously engaged to brake the vehicle. This constitutes a so-called negative brake. Accordingly, the vehicle can be braked when the pilot pressure does not act on the high / low speed switching valve 73, so that the safety is improved, and the high speed clutch 40 and the low speed clutch 41 are improved.
Since the control circuit is simply constructed, it is easy to manufacture.

Further, an engine speed sensor 66 for detecting overrunning of the engine (hereinafter referred to as first detecting means 6)
Say 6. ), The controller 63 receives the signal from the first detecting means 66, performs an operation, and based on the operation result, when the engine speed stored in advance exceeds a set value, the high speed clutch 40 and the low speed clutch 41 and 2
In order to stop the vehicle by double engagement, the high / low speed switching valve 7
3 is not operated. For this reason, the overrun rotation of the engine is detected in advance, and the high-speed clutch 40 and the low-speed clutch 41 are simultaneously double-engaged.
The vehicle can be braked to automatically prevent overrun. This allows the vehicle to run safely even when the vehicle is downhill, and is particularly useful for roads and construction vehicles during land reclamation work.

Further, an engine speed sensor 66 (hereinafter referred to as a first detecting means 66) for detecting a stopped state of the engine.
Say ), The controller 63 receives the signal from the first detecting means 66 and calculates the result. Based on the calculation result, when the engine speed stored in advance is equal to or less than the set value, the high-speed clutch 40 and the low-speed clutch 41 The high and low speed switching valve 73 is not operated in order to stop the vehicle by double-engaging the two. Therefore, by turning off the engine key switch when the vehicle is parked, the high-speed clutch 40 and the low-speed clutch 41 are simultaneously double-engaged, and the vehicle can be automatically stopped. As a result, as described above, the high-speed clutch 40
It is not necessary to provide a brake device in addition to the low-speed clutch 41 and the vehicle can be safely parked only by turning off the engine key switch, and the structure is simple and the manufacturing cost is low.

Further, a hydraulic sensor 65 (hereinafter, referred to as second detecting means 65) for detecting the traveling oil pressure of the hydraulic motor 2 is provided. Based on the calculation result, the high-speed clutch 40 is engaged when the driving oil pressure is equal to or less than the set value of the traveling oil pressure stored in advance, or the low-speed clutch 41 is engaged when the operation result is equal to or more than the setting value of the driving oil pressure. Therefore, the high / low speed switching valve 73 is not operated. For this reason, the high-speed clutch 4 is automatically turned on according to the running load conditions of the vehicle (a road surface having unevenness, a steep slope, a flat road, or the like).
0, or since the low-speed clutch 41 can be engaged, the traveling performance is improved. Accordingly, stable traveling can be performed even when traveling load conditions differ depending on the work site, which is useful for a construction vehicle.

Further, a traveling lever 64 for switching a traveling electromagnetic valve 62 disposed between the hydraulic pump 61 and the hydraulic motor 2 is provided, and a controller 63 receives an operation position signal of the traveling lever 64 and the traveling lever 64 When the neutral position is reached, the traveling electromagnetic valve 62 is set to the neutral position, and the high / low speed switching valve 73 is not operated in order to stop the vehicle by double-engaging the high speed clutch 40 and the low speed clutch 41. is there. By setting the traveling lever 64 to the neutral position, the high-speed clutch 40 and the low-speed clutch 41 are simultaneously double-engaged, and the vehicle can be automatically stopped. For this reason, as described above,
It is not necessary to incorporate a brake device as described in Japanese Patent Application Laid-Open No. 9768 and Japanese Patent Application Laid-Open No. 7-174209.
Thus, the vehicle can be safely parked only by setting the traveling lever to the neutral position, and the structure is simple and the manufacturing cost is low. If the vehicle can be parked safely only by setting the traveling lever to the neutral position, in addition to the above-described method of parking the vehicle by turning off the engine key switch, the safety is further improved and the construction machine Useful as

Next, a second embodiment of the traveling drive device for a construction vehicle according to the present invention will be described with reference to FIGS. FIG. 3 is a side sectional view of the traveling drive device, and FIG. 4 is a skeleton diagram thereof. Note that the control circuit of the traveling drive device of FIGS. 7 and 8 described in the first embodiment can also be applied to the second embodiment, and the detailed structure and operation of the control circuit will not be described here. Further, the second embodiment will be described using a three-stage planetary gear reducer, but a two-stage planetary gear reducer or
The present invention can be applied to other planetary gear units. Similar to the first embodiment, the main part of the second embodiment is to drive the rotation of the output shaft of the hydraulic motor to a sprocket (drive wheel) via a high-speed clutch incorporated in a planetary gear reducer and a low-speed clutch. Is transmitted. The high-speed clutch and the low-speed clutch are described in detail in
By the control means, the high speed clutch and / or the low speed clutch can be brought into the engaged state. The second embodiment requires a brake device in addition to the conventional high-speed clutch and low-speed clutch.
In the second embodiment of the present invention, the drive device described in JP-A-129768 and JP-A-7-174209 is improved, and the brake device is omitted, and the high-speed clutch and the low-speed clutch are simultaneously double-engaged. In this case, the vehicle is put into a stopped state by braking. Hereinafter, the traveling drive device of the second embodiment will be described in order. First, the output shaft 3 of the fixed displacement hydraulic motor 2 fixed to the case 1 shown in FIGS.
The first sun gear 15 of the first planetary gear reducer 10 and the second
The second sun gear 21 of the planetary gear reducer 20 is fixed adjacently in parallel. The first carrier 13 that supports the first planetary gear 12 that meshes with the first sun gear 15 of the first planetary gear reducer 10 and the second ring gear 24 of the second planetary gear reducer 20 are engaged. 2nd planetary gear reducer 2
The second carrier 23 that supports the second planetary gear 22 that meshes with the second sun gear 21 and the second ring gear 24 of FIG.
, The third sun gear 31 of the third planetary gear reducer 30 is engaged. The third ring gear 34 of the third planetary gear reducer 30 is fixed to the case 1 and the third sun gear 31
A third planetary gear 33 meshing with the third ring gear 34 is rotatably mounted on the drum 5 rotatably mounted on the case 1 via the bearing 4. A sprocket 7 is fixed to the drum 5. A high-speed clutch 40 is provided between the first ring gear 11 meshing with the first planetary gear 12 of the first planetary gear reducer 10 and the case 1, and the second ring gear 24 of the second planetary gear reducer 20 and the case 1 Is provided with a low-speed clutch 41.
The high-speed clutch 40 is engaged by a spring 42 (hereinafter referred to as O).
Say N. ), And the pilot pressure acts on the clutch 40 to be in a non-engaged state (hereinafter, referred to as OFF).
Further, the low speed clutch 41 is engaged (hereinafter, referred to as ON) by the spring 43, and the clutch 41 is disengaged (hereinafter, referred to as OFF) by a pilot pressure acting on the clutch 41.

Next, the traveling drive device shown in FIGS. 3 and 4 will be described. (1) At low speed running The low speed clutch 41 is turned on and the high speed clutch 40 is turned off.
By driving the fixed displacement hydraulic motor 2, power is supplied from the second sun gear 21 of the second planetary gear reducer 20 via the second planetary gear 22 to the second carrier 23.
Is transmitted to Since the third carrier 31 of the third planetary gear reducer 30 is fixed to the second carrier 23, power is transmitted to the drum 5 via the third planetary gear 33 and drives the sprocket 7. (2) During high-speed running The high-speed clutch 40 is turned on and the low-speed clutch 41 is turned off.
By doing so, the second carrier 23 becomes the second sun gear 2
Driven by the first and second ring gears 24, the sprocket 7 is rotated at high speed. (3) During braking, the high-speed clutch 40 and the low-speed clutch 41 are simultaneously turned on.
By acting as a dynamic brake,
Brakes.

With the above configuration, the gear ratio can be further increased, and the capacity of the hydraulic motor can be reduced to further reduce the size and cost. Further, the dimension L in the longitudinal direction can be shortened, so that the whole can be made compact. Further, in both high-speed and low-speed traveling, the other high-speed or low-speed clutch can be turned on to operate as a dynamic brake, and the braking feeling is improved. When the pilot pressure is cut off while the engine is stopped, the high-speed clutch 40 and the low-speed clutch 41 are urged by the springs 42 and 43, and both clutches 40 and 41 are turned on. .

The operation of FIGS. 3 and 4 will be described. Second
According to the traveling drive device of the embodiment, the first sun gear and the first
A first planetary gear reducer including a first planetary gear engaged with the sun gear and supported by the first carrier and engaged with the first ring gear; a second sun gear driven to rotate by an output shaft of a hydraulic motor; A second-stage planetary gear reducer meshed with a sun gear and supported by a second carrier, and a second planetary gear meshed with a second ring gear meshed with the first carrier is arranged in parallel with the first carrier. 13 and a low-speed clutch 41 for interrupting power to the second carrier 23.
And the first control means for controlling the high-speed clutch 40 and / or the low-speed clutch 41 to be in an engaged state, so that the traveling drive device can reduce the L dimension in the longitudinal direction. Can be. As a result, the traveling drive device can be made compact, so that the production cost is low. The high-speed clutch 40 can be engaged to perform high-speed traveling, and the low-speed clutch 41 can be engaged to perform low-speed traveling. When the vehicle is stopped, the high-speed clutch 40 and the low-speed clutch 41 Are double-engaged to act as a brake. For this reason, the second embodiment is disclosed in Japanese Patent Application Laid-Open Nos. 53-129768 and
Since it is not necessary to incorporate a brake device as described in JP-A-174209, the traveling drive device can be simplified.

FIG. 5 is a skeleton diagram of a third embodiment of a traveling drive device for a construction vehicle according to the present invention, and FIG. 6 is a skeleton diagram of a fourth embodiment. Although a detailed description of the configuration is omitted, in the case of the third embodiment shown in FIG. 5, the first embodiment described above is different from the first sun gear 15 of the first planetary gear reducer 10 in the first embodiment.
Is provided with a low-speed clutch.
The ring gear 11 is provided with a low-speed clutch 41. In this case, the interstage ratio is 2.5 to 10. Further, in the case of the fourth embodiment shown in FIG. 6, the ring gear 34 of the third planetary gear reducer 30 is fixed in the above-described second embodiment,
In the fourth embodiment, the carrier 5 is fixed, and the step ratio is 1.
2 to 4.

Next, automatic control of the traveling drive device of the construction vehicle according to the present invention will be described with reference to FIGS. 1, 3, 7, and 8 with reference to the flowcharts of FIGS. 9 to 12. First, a first control flowchart for automatically controlling a traveling drive device of a construction vehicle according to the present invention will be described with reference to FIGS. Note that the following description is for a high-speed clutch in forward running,
Alternatively, a method of controlling the low-speed clutch will be described. FIG.
In S101, the traveling lever 64 is set to the forward (F) position. As a result, a command signal is output from the controller 63 to the traveling solenoid valve 62, and the traveling solenoid valve 62 is switched to the forward (F) position in S102. At the same time, when the high / low speed changeover switch 70 is switched to the high speed side in S103, the command signal for turning the high speed solenoid valve 71 to the open position (ON) is output from the controller 63 as described above.
In this state, the pilot pump 7 shown in FIG.
The pilot pressure discharged from 4 acts on the high / low speed switching valve 73 via the high speed solenoid valve 71, and the switching valve 73 is switched to the high speed (a) position. As a result, the pilot pressure acts on the low-speed clutch 41 from the high-speed (a) position of the high-low switching valve 73, and turns off the clutch 41. At this time, the high speed clutch 40 is in communication with the drain line via the high / low speed switching valve 73. For this reason, the pilot pressure acting on the high-speed clutch 40 is drained, and the clutch 40 is pushed by the spring 42 to be turned ON, so that the traveling drive device 50 is driven for high-speed traveling.

In step S104, a signal from the oil pressure sensor 65 is received and calculated, and if the traveling oil pressure is 330 kg / cm ² or more, 1
It is determined whether or not the operation has continued for at least sec. If YES, the command signal to the high-speed solenoid valve 71 is not output in S105, the valve 71 is closed (OFF), and the low-speed solenoid valve 72 is turned off. With the open position (ON), as described above, FIG.
The pilot pressure discharged from the pilot pump 74 shown in FIG. 7 acts on the high / low speed switching valve 73 via the low speed solenoid valve 72, and the switching valve 73 is switched to the low speed (C) position.
As a result, the pilot pressure acts on the high-speed clutch 40 from the low-speed (C) position of the high-low speed switching valve 73, and turns off the clutch 40. At this time, the low speed clutch 41
A communication state is established with the drain pipe via the high / low speed switching valve 73. For this reason, the pilot pressure acting on the low-speed clutch 41 is drained, and the clutch 41 is pushed by the spring 43 to be turned on, and the traveling drive device 50 is driven for low-speed traveling. That is, the traveling hydraulic pressure is 330 kg
When the speed is longer than / cm ² and continues for 1 ^second or more, the running resistance of the vehicle is large, and high speed running is inappropriate, and switching to low speed running is performed.

At S106, the traveling oil pressure is 220 kg / cm.
It is determined whether ² or more continues for 1 ^second or more.
If NO, the travel lever 64 is neutral (N) in S108.
If NO, the flow returns to S106 to continue the low-speed running, and if YES, the high-speed electromagnetic valve 7 is determined in S118.
No command signal is output to 1 and the low-speed solenoid valve 72, and both valves 71, 72 are set to the closed position (OFF). Then S1
At 19, no command signal is output to the traveling solenoid valve 62, the valve 62 is set to the neutral (N) position, and the vehicle is braked and stopped at S120. The running control ends.

If YES in S106, S107
, The low-speed solenoid valve 72 is set to the closed position (OFF), and as described above, the high-speed solenoid valve 71 is set to the open position (ON) to drive at high speed. In this high-speed running state, the process proceeds to S109, and when the result of S104 is NO, the process also proceeds to S109. In S109, it is determined whether the traveling oil pressure is equal to or less than the set oil pressure according to the engine speed. If NO, it is determined in S111 that the traveling lever 64 is in the neutral position (N).
If NO, the process returns to S104, and if YES, S118
No command signal is output to the high-speed solenoid valve 71 and the low-speed solenoid valve 72, and both valves 71, 72 are set to the closed position (OFF). Next, in step S119, no command signal is output to the traveling electromagnetic valve 62, and the valve 62 is set to the neutral (N) position.
, The vehicle is stopped by braking, the overrun of the hydraulic motor 2 is prevented, and the traveling control ends.

If YES in S109, the hydraulic motor 2
Is determined to be overrun, the high-speed solenoid valve 71 is set to the closed position (OFF) in S110, whereby both the low-speed solenoid valve 72 and the high-speed solenoid valve 71 are closed (OF).
F), the pilot pressure does not act on the high / low speed switching valve 73 as described above, and the valve 73 is in the neutral position (N),
The high-speed clutch 40 and the low-speed clutch 41 are both engaged (ON), and the vehicle is braked to prevent overrun. Next, in S112, it is determined whether the set time has elapsed and the traveling hydraulic pressure has recovered to the normal traveling state.
When it is O, it is determined that the overrun of the hydraulic motor 2 has not been eliminated, and the traveling electromagnetic valve 62 is moved to the neutral position (N) in S113 to reduce the opening amount of the valve 62. Thus, the supply amount of the pressure oil from the hydraulic pump 61 to the hydraulic motor 2 is reduced, so that the rotation speed of the motor 2 is reduced and overrun is prevented. In S114, it is determined whether the traveling hydraulic pressure has recovered to the normal traveling state.
13 and if YES, the traveling solenoid valve 6
Set 2 to the forward position (F). In this state, the flow shifts to S116, and when YES in S112, the flow shifts to S116. At S116, the high-speed electromagnetic valve 71 is set to the open position (ON), and the high-speed driving is performed as described above. S
At 117 it is determined whether the traveling lever 64 is at the neutral position (N). If NO, the process returns to S104, and if YES, the command signal to the high-speed solenoid valve 71 and the low-speed solenoid valve 72 is output at S118. Without closing both valves 71 and 72 to the closed position (O
FF). Next, in S119, the command signal to the traveling electromagnetic valve 62 is not output, the valve 62 is set to the neutral (N) position,
In S120, the vehicle is braked and stopped. The running control ends.

FIGS. 1 and 3 show a second control flow chart for automatically controlling the traveling drive device of the construction vehicle according to the present invention.
This will be described with reference to FIGS. 10 and 11 with reference to FIGS.
In the following description, a method of controlling low-speed traveling by controlling a low-speed clutch in forward traveling will be described. In S201 shown in FIG. 11, the traveling lever 64 is set to the forward (F) position. As a result, a command signal is output from the controller 63 to the traveling electromagnetic valve 62, and the traveling electromagnetic valve 62 is switched to the forward (F) position in S202. At the same time, when the high / low speed switch 70 is switched to the low speed side in S203, the command signal for opening the low speed solenoid valve 72 is output from the controller 63 as described above. For this reason, the pilot pressure discharged from the pilot pump 74 acts on the high / low speed switching valve 73 via the low speed solenoid valve 72,
The switching valve 73 is switched to the low speed (C) position. As a result, the pilot pressure becomes lower (C) of the high / low speed switching valve 73.
It acts on the high-speed clutch 40 from the position, and turns off the clutch 40. At this time, the low-speed clutch 41 is in communication with the drain pipe via the high-low speed switching valve 73. For this reason, the pilot pressure acting on the low-speed clutch 41 is drained, and the clutch 41 is pushed by the spring 43 to be turned on, and the traveling drive device 50 is driven for low-speed traveling.

In S204, it is determined whether or not the traveling oil pressure is equal to or less than a set oil pressure according to the engine speed.
At 206, it is determined whether the travel lever 64 is at the neutral position (N). If NO, the process returns to S204. If YES, the command signal to the low-speed solenoid valve 72 is not output at S213,
The valve 72 is set to the closed position (OFF). Next, in S214, the command signal to the traveling electromagnetic valve 62 is not output, and the traveling electromagnetic valve 62 is set to the neutral (N) position. In S215, the vehicle is braked and stopped, and the traveling control ends.

If YES in S204, the hydraulic motor 2
Is determined to be overrun, the low-speed solenoid valve 72 is set to the closed position (OFF) in S205, whereby both the low-speed solenoid valve 72 and the high-speed solenoid valve 71 are closed (OF).
F), the pilot pressure does not act on the high / low speed switching valve 73 as described above, and the valve 73 is in the neutral position (N),
The high-speed clutch 40 and the low-speed clutch 41 are both engaged (ON), and the vehicle is braked to prevent overrun. Next, in S207, it is determined whether or not a set time has elapsed and the traveling hydraulic pressure has recovered to a normal traveling state.
If it is O, it is determined that the overrun of the hydraulic motor 2 has not been eliminated, and the traveling electromagnetic valve 62 is moved to the neutral position (N) in S208 to reduce the opening amount of the valve 62. Thus, the supply amount of the pressure oil from the hydraulic pump 61 to the hydraulic motor 2 is reduced, so that the rotation speed of the motor 2 is reduced and overrun is prevented. In step S209, it is determined whether the traveling hydraulic pressure has recovered to the normal traveling state.
08, and if YES, the traveling solenoid valve 6
Set 2 to the forward position (F). In this state, the flow shifts to S211. If YES in S207, the flow shifts to S211. At S211, the low-speed electromagnetic valve 72 is set to the open position (ON), and the driving at low-speed traveling is continued as described above. In S212, it is determined whether the traveling lever 64 is at the neutral position (N). If NO, the process returns to S204. If YES, the command signal to the low-speed solenoid valve 72 is not output in S213, and The position is the closed position (OFF). Then S21
4 does not output a command signal to the traveling solenoid valve 62,
2 is set to the neutral (N) position, and the vehicle is braked and stopped in S215. The running control ends.

As described in the first and second control flowcharts, according to the traveling drive device for a construction vehicle according to the present invention, high-speed automatic control can be performed by preventing overrun during traveling of the vehicle. As well as the switching control of the high speed clutch and the low speed clutch is performed reliably,
Even if the running resistance becomes large due to a change in the running road surface or the like, the vehicle can be smoothly driven. In addition, the engine speed and running oil pressure are always input to the controller,
Calculation is performed based on these input signals, and high-speed or low-speed traveling drive is automatically performed based on the result of the computation, and the conventional traveling drive device requires a dedicated brake in addition to the high-speed clutch and the low-speed clutch. Things are
ADVANTAGE OF THE INVENTION According to the traveling drive device of this invention, it is possible to stop a vehicle by applying a brake by performing double engagement of a high-speed clutch and a low-speed clutch, and to improve the traveling performance of the traveling drive device as a construction vehicle. The present invention is useful as a traveling drive device for a construction vehicle, because it is possible to improve the safety, to enhance the safety, to simplify the traveling drive device and to reduce the cost. It goes without saying that the traveling drive device of the present invention can be applied to industrial vehicles other than construction vehicles.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a first embodiment of a traveling drive device of the present invention.

FIG. 2 is a skeleton diagram of the same.

FIG. 3 is a side sectional view of a second embodiment of the traveling drive device of the present invention.

FIG. 4 is a skeleton diagram of the same.

FIG. 5 is a skeleton diagram of a third embodiment of the traveling drive device of the present invention.

FIG. 6 is a skeleton diagram of a fourth embodiment of the traveling drive device of the present invention.

FIG. 7 is a control circuit diagram of the traveling drive device of the present invention.

FIG. 8 is a block diagram of the control device.

FIG. 9 is a first flowchart of the traveling drive device of the present invention.

FIG. 10 is a continuation of the first flowchart.

FIG. 11 is a second flowchart of the traveling drive device of the present invention.

FIG. 12 is a continuation of the second flowchart.

FIG. 13 is a side sectional view of a first example of a conventional traveling drive device.

FIG. 14 is a skeleton diagram of the same.

FIG. 15 is a side sectional view of a second example of the conventional traveling drive device.

FIG. 16 is a skeleton diagram of the same.

[Explanation of symbols]

1 ... case, 2 ... hydraulic motor, 3 ... output shaft, 4 ... bearing,
5: drum, 6: ring gear, 7: sprocket, 10
... 1st planetary gear reducer, 11 ... 1st ring gear, 12 ...
1st planetary gear, 13 ... 1st carrier, 14 ... shaft,
15: first sun gear, 20: second planetary gear reducer, 21
... second sun gear, 22 ... second planetary gear, 23 ... second carrier, 24 ... second ring gear, 30 ... third planetary gear reducer, 31 ... third sun gear, 32 ... third carrier,
33: third planetary girl, 34: third ring girl, 4
0: High speed clutch, 41: Low speed clutch, 42, 43 ...
Spring, 50: traveling drive device, 60: engine, 61: hydraulic motor, 62: traveling solenoid valve, 63: controller, 6
4 travel lever, 65 hydraulic pressure sensor (second detection means),
66 ... engine speed detection sensor (first detection means), 7
0: high / low speed switch, 71: high speed solenoid valve, 72: low speed solenoid valve, 73: high / low speed switch valve, 74: pilot pump, 75: pilot line.

Claims (7)

[Claims] 1. A hydraulic motor driven by receiving a supply of pressure oil from a hydraulic pump driven by an engine, a planetary gear reducer connected to an output shaft of the hydraulic motor, and power from the planetary gear reducer. In a traveling drive device for a construction vehicle that drives a sprocket via a gear reducer, a coaxial drive shaft between the hydraulic motor (2) and the carrier (13) of the planetary gear reducer is coaxial with the output shaft of the hydraulic motor (2). When the output shaft of the hydraulic motor (2) is engaged with the carrier (13), the driving force of the high-speed rotation of the hydraulic motor (2) is transmitted through the carrier (13) of the planetary gear reducer. A high-speed clutch (40) for transmitting the gear to the gear reducer, and disposed between the hydraulic motor (2) and the carrier (13) of the planetary gear reducer coaxially with the high-speed clutch (40), and When engaged with the sun gear (15), the driving force of the low-speed rotation of the hydraulic motor (2) is A low-speed clutch (41) for transmission from a ring gear (11) of the reduction gear to a gear reduction gear via a carrier (13) supporting a planetary gear (12) meshing with the sun gear (15); a high-speed clutch (40); A traveling control device for a construction vehicle, comprising: first control means for simultaneously engaging the low-speed clutch (41) to stop the vehicle. 2. A hydraulic motor driven by receiving a supply of pressure oil from a hydraulic pump driven by an engine, a first sun gear rotatably driven by an output shaft of the hydraulic motor, and a first sun gear meshed with the first sun gear. A first stage planetary gear reducer having a first planetary gear supported by one carrier and meshing with the first ring gear; a second sun gear rotatably driven by an output shaft of a hydraulic motor; and a second sun gear engaged with the second sun gear. A second stage planetary gear reducer supported by the second carrier and including a second planetary gear engaged with a second ring gear engaged with the first carrier; and a planetary gear reducer comprising: In a traveling drive device for a construction vehicle in which a sprocket is driven by rotation of a two-ring gear, a first-stage planetary gear reducer and a second-stage planetary gear reducer are arranged in parallel. A high-speed clutch (40) for connecting and disconnecting power to one carrier (13) and a low-speed clutch (41) for connecting and disconnecting power to the second carrier (23) are coaxially arranged in parallel, and A traveling drive device for a construction vehicle, comprising: first control means for controlling a clutch (40) and / or a low speed clutch (41) to an engaged state. 3. The traveling drive device for a construction vehicle according to claim 1, wherein said first control means includes a high / low speed changeover switch (70) for switching between a high speed position, a low speed position, and a neutral position; One of the high-speed solenoid valve (71) and the low-speed solenoid valve (72) connected in parallel with the pump, and one of the high-speed solenoid valve (71) and the low-speed solenoid valve (72)
(40) and the low-speed clutch (41), the other of which is connected to the high-low speed switching valve (73) and the high-speed switching switch (70) when the high-speed clutch (40) is in the high-speed position so that the vehicle travels at high speed. Command to the high-speed solenoid valve (71), and when the high-low speed switch (70) is in the low-speed position, instructs the low-speed solenoid valve (72) to engage the low-speed clutch (41) and run at low speed. Output and the high-speed clutch when the high-low speed switch (70) is in the neutral position.
(40) and a controller (63) that does not output a command to the high-speed solenoid valve (71) and the low-speed solenoid valve (72) to apply the brake to the vehicle by simultaneously engaging the low-speed clutch (41). A traveling drive device for a construction vehicle, comprising: 4. A first detecting means (66) for detecting overrunning rotation of the engine, receiving and calculating a signal from the first detecting means (66), and pre-stored based on a result of the calculation. When the engine speed exceeds the set value, the controller does not output a command signal to the high / low speed switching valve (73) so that the high speed clutch (40) and the low speed clutch (41) are double engaged to stop the vehicle. The traveling drive device for a construction vehicle according to any one of claims 1 to 3, further comprising (63). 5. It has a first detecting means (66) for detecting a stopped state of the engine, calculates by receiving a signal from the first detecting means (66), and stores in advance based on a result of the calculation. High-speed clutch (4
A controller (63) that does not output a command signal to the high / low speed switching valve (73) so as to stop the vehicle by double-engaging the low speed clutch (41) with the low speed clutch (41). 5. The travel drive device for a construction vehicle according to any one of 4. 6. A second detecting means (65) for detecting a traveling oil pressure of the hydraulic motor (2), receiving a signal from the second detecting means (65), performing an arithmetic operation, and based on the arithmetic result, If the travel hydraulic pressure is less than the pre-stored travel oil pressure, the high-speed clutch (4
0), or a controller that does not output a command signal to the high / low speed switching valve (73) so as to engage the low speed clutch (41) when the calculation result is greater than or equal to the set value of the traveling oil pressure.
The driving device for a construction vehicle according to any one of claims 1 to 5, further comprising (63). 7. A traveling lever (64) for switching a traveling solenoid valve (62) disposed between a hydraulic pump (61) and a hydraulic motor (2).
In response to the operation position signal of the traveling lever (64), when the traveling lever (64) is in the neutral position, the traveling solenoid valve (62) is in the neutral position, and the high speed clutch (40) and the low speed The controller (6) that does not output a command signal to the high / low speed switching valve (73) so as to stop the vehicle by double-engaging the clutch (41).
The traveling drive device for a construction vehicle according to any one of claims 1 to 6, further comprising (3).