JPH08268320A - Hydraulic travel driving mechanism - Google Patents

Abstract

PURPOSE: To dispense with a conventional mechanical transmission system and obviate a vibration control means so as to materialize cost reduction and operability improvement, by performing the variable cam plate operation of HST with pilot oil pressure, and also, providing a hydraulic valve, which opens or closes with the operation of a travel operation lever, in this pilot oil pressure circuit. CONSTITUTION: When each travel operation lever is operated and set in travel stage, pilot pressure is generated in a pilot circuit 33 for a timer valve, and it changes a timer valve BV over into valve-open condition, and sends pressure oil into each parking brake cylinder 29 so as to release a parking brake. At this time, by the interposition of each shaft valve 32, not matter which of pilot circuits 24 and 25 for control of each cam plate the pressure oil may flow to, the pressure oil flows to the pilot circuit 33 for a timer valve. On the other hand, when each travel operation lever is returned into neutral position (stopping means), the pressure oil is let out gradually from each parking brake cylinder 29 to a tank T. When a travel stop lever or a travel stop switch is turned off, a travel stop valve CV opens, and the pressure oil is not supplied to the travel operation valve SV.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler type transport vehicle or the like which can independently drive left and right traveling devices.
The present invention relates to improvement of a pump two-motor type hydraulic traveling drive mechanism.

[0002]

2. Description of the Related Art Conventionally, a configuration is known in which two HSTs are provided in a traveling vehicle in order to independently drive and control a traveling device such as a crawler traveling device provided on the left and right of the traveling vehicle. A configuration is also known in which each HST can be controlled based on the operation of one traveling operation lever.

Among these, first, the HST and the traveling operation lever are conventionally connected via a mechanical mechanism such as a link or a rod.

Further, a parking brake has been conventionally provided so as to prevent the vehicle from unexpectedly traveling when the vehicle is stopped. However, in the past, the parking brake is configured to be manually operated and released. In addition, conventionally, the actual Kaihei 3-279,
As shown in Japanese Utility Model Laid-Open Nos. 3-30603 and 3-108901, it is well known that the brake is released by the hydraulic pressure of the pilot hydraulic circuit, and if the pilot pressure decreases, the brake is operated by the spring force. Is complicated, and
It was not configured to operate two traveling motors and HST.

Further, in the conventional seat and traveling operation lever structure in the cabin, a rotary seat has been conventionally provided so that the user can work in the backward direction when moving backward. The travel operation lever is separate from the seat so that the travel operation lever can be operated even when facing the reverse direction.
In addition to the traveling operation lever provided in front of the seat and operated when moving forward, a traveling operation lever for traveling backward is provided behind the seat.

Further, the traveling operation lever for operating the HST is
The lever returns to the neutral position when the lever is released so that it can be easily and reliably positioned at the neutral position (stop stage).

Further, the hydraulic hose piping is actually open flat 3-64.
As shown in 883, there is a device in which a guide for connection is specially provided, but generally, the conventional HST and hydraulic hose piping configuration will be described with reference to FIGS. 22 to 24. The hydraulic pumps P1 and P2, which are arranged on the main frame 1 of the vehicle, are connected to the engine E, and the hydraulic motors M1 and M2 are connected to the drive wheels 2a and 2a. It was fixed to the outer surface of the outer vertical frame 8. And such H
With the arrangement configuration of ST, the piping of the hydraulic hoses H1, H2, H3, H4 between the pump and motor in each HST is
Since the hydraulic hoses are extended in the left-right direction from the hydraulic pumps P1 and P2, it is unavoidable that an intersecting portion is generated. The hydraulic hoses H1 to H4 are arranged in a straight line in the front and rear, and the fan pulley FP (FB
Is a fan belt), and an intersection portion of all the hoses H1 to H4 is provided on the lower side.

[0008]

First, in the operation system of the traveling operation lever, the vibration of the engine is easily transmitted by the conventional mechanical mechanism such as the link rod. In order to absorb this, it is better to provide a soft elastic material (rubber, etc.) as a vibration-proof material, but this will hinder the operation system,
Since it could lead to erroneous operation, it had to be stiffened to a certain extent, which inevitably resulted in insufficient vibration absorption. Further, the link rod and the like have a problem that the operation is deteriorated due to the accumulation of earth and sand, and the operation load of the lever is heavy.

Speaking of safety, first of all, in the conventional manual parking brake, there is a risk that the vehicle may move unknowingly because the driver forgets the braking operation when the vehicle is stopped on a slope or the like. Further, in the case of being of a manual type, there is a person who makes an erroneous operation of turning on the parking brake and braking when traveling, which causes damage to the parking brake. In addition, although it is conceivable that the traveling operation lever is accidentally put in the traveling stage when the vehicle is stopped, conventionally, there is no means for preventing such a situation.

Next, when the traveling operation levers are separately provided for forward traveling and backward traveling as in the conventional case, the traveling operating levers are provided before and after the seat, so that the working space is narrow and Since it is a separate body, there is a risk of hitting a part of the body against the lever while sitting on the seat and rotating.

Further, when the traveling drive is maintained, the traveling operation lever has to be fixed at the traveling stage (the hand will return to the stop stage if the hand is released). The vibration of the lever made the operator feel pain.

In the HST hydraulic hose piping structure, in the conventional case, the intersection of the hydraulic hoses on the lower side of the fan pulley of the engine is lifted up when the sediment D is deposited below as shown in FIG. The hose may be damaged by interfering with the fan pulley FP. In addition, the hydraulic hose from the intersection to the hydraulic motor may be exposed and may be damaged by being caught on an object while traveling. As described above, the hydraulic hose was highly likely to be damaged.

[0013]

The present invention uses the following means in order to solve the above problems. That is, in a two-pump, two-motor type hydraulic traveling drive mechanism in which a traveling vehicle is equipped with two HSTs and each of the HSTs controls the traveling devices on the left and right, one operation of the movable swash plate of the HST is performed. A pilot hydraulic circuit is provided to operate with pilot pressure oil, and a hydraulic valve that opens and closes by operating the travel operation lever is provided in the pilot hydraulic circuit. Furthermore, when the travel operation lever is set to the travel stage, it automatically When the parking brake is released and set from the running stage to the stop stage, the parking brake is automatically applied gradually.

Further, in a two-pump, two-motor type hydraulic traveling drive mechanism in which a traveling vehicle is provided with two HSTs, and each HST drives and controls the left and right traveling devices one by one.
In order to perform the operation of the movable swash plate of the HST with pilot pressure oil of the HST, a pilot hydraulic circuit is provided, and in the pilot hydraulic circuit, a hydraulic valve that opens and closes by operating the traveling operation lever and a switch operation upstream of the hydraulic valve are provided. And a hydraulic valve for opening and closing the valve.

Further, in a two-pump, two-motor type hydraulic traveling drive mechanism in which a traveling vehicle is provided with two HSTs, and each HST drives and controls the left and right traveling devices one by one.
A pilot hydraulic circuit is provided to perform the operation of the movable swash plate with the pilot pressure oil of the HST, and the pilot hydraulic circuit is switched between a hydraulic valve that opens and closes by operating the traveling operation lever and the seat rotation. A rotary valve is provided, and the travel operation lever rotates integrally with the seat.

Further, in a two-pump, two-motor type hydraulic traveling drive mechanism in which the traveling vehicle is provided with two HSTs and each HST drives and controls the left and right traveling devices one by one,
Each of the traveling operation levers provided for operating the movable swash plate is fixed at the traveling stage and provided with a fixing member that can be easily unlocked.

Further, in a two-pump, two-motor type hydraulic traveling drive mechanism in which a traveling vehicle is provided with two HSTs and each of the HSTs drives and controls the left and right traveling devices one by one.
Was arranged in the main frame of the vehicle, and the hydraulic hose between the hydraulic pump and the hydraulic motor in each HST was fitted into the fitting hole formed in the lateral frame of the main frame for piping.

[0018]

Next, the operation of the present invention will be described. HST
In order to perform the operation of the movable swash plate with the pilot pressure oil of the HST, a pilot hydraulic circuit is provided, and the pilot hydraulic circuit is provided with a hydraulic valve that opens and closes by operating the traveling operation lever. Switching operation of the movable swash plate can be performed without using mechanical transmission means such as. Furthermore, by providing a parking brake that is automatically operated and released in conjunction with the operation of the travel operation lever, the conventional manual operation of the parking brake is unnecessary, and when switching from the travel stage to the stop stage, Safety is secured by gradually applying the parking brake.

Further, a pilot hydraulic circuit is provided so that the pilot pressure oil of the HST can be used, and in the pilot hydraulic circuit, a hydraulic valve that opens and closes by operating the traveling operation lever and an opening / closing valve that is operated upstream by a switch are operated. When the hydraulic valve is closed by operating the switch, the supply of pilot pressure oil to the hydraulic valve that opens and closes by operating the travel operation lever is stopped, and the travel operation lever is operated. Also, the pressure oil for controlling the movable swash plate of the hydraulic pump does not flow, and therefore the traveling drive is stopped.

In addition, a pilot hydraulic circuit is provided so that the pilot pressure oil of the HST can be used, and a hydraulic valve that opens and closes by operating the traveling operation lever and a rotary valve that switches with the rotation of the seat are provided in the pilot hydraulic circuit. And the traveling operation lever is configured to rotate integrally with the seat, so that the traveling operation levers disposed on the left and right and the traveling devices on the left and right to be steered are on the same side regardless of whether the vehicle is facing forward or backward. , A traveling operation lever separate from the conventional two front and rear seats is unnecessary.

Further, by providing a traveling operation lever provided for operating the movable swash plate of each HST at the traveling stage and provided with a fixing member which can be easily released from the fixation, traveling drive can be performed for a long time. When maintaining, the travel operation lever can be fixed and the travel drive can be maintained even if the hand is released. In addition, the fixation can be easily released, and the deceleration operation and the stop operation can be performed immediately.

Further, both HSTs for driving the left and right traveling devices are arranged in the main frame of the vehicle, and a hydraulic hose between the hydraulic pump and the hydraulic motor in each HST is fitted in the lateral frame of the main frame. By inserting the pipe into the insertion hole and piping, the slack portion and the intersecting portion of the hydraulic hose are not generated, and therefore the hose is not hooked and does not interfere with other members.

[0023]

Embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a crawler-type carrier adopting the hydraulic traveling drive mechanism of the present invention, FIG. 2 is a side view of the same, and FIG.
Is a bottom view, FIG. 4 is a plan view showing the arrangement of the engine, HST, and hydraulic hoses in the main frame 1, FIG. 5 is a side view, FIG. 6 is a front view, and FIG. 7 is a side view of the cabin and its interior. FIG. 8 is a perspective view from the upper rear of the cabin, and FIG. 9 is a travel control lever L1 / L2.
10 is a plan view, FIG. 11 is a side view, FIG. 11 is a side view, FIG. 12 is a perspective view showing a structure in which a traveling operation lever can be fixed to a traveling stage, and FIG. 13 is a hydraulic traveling drive of the present invention. 1 is a hydraulic circuit diagram of the mechanism, FIG. 14 is a block diagram showing the hydraulic system of the hydraulic traveling drive mechanism when the seat is facing forward, FIG.
5 is a block diagram showing the communication structure of the rotary valve, FIG. 16 is a block diagram showing the hydraulic system of the hydraulic traveling drive mechanism when the seat is facing backward, and FIG. 17 is a block diagram showing the communication structure of the rotary valve. 1
19 is a block diagram showing the hydraulic system of the hydraulic traveling drive mechanism when the parking brake is applied when traveling is stopped, FIG.
FIG. 20 is a block diagram showing a hydraulic system of the hydraulic traveling drive mechanism when the parking brake is released during traveling drive. FIG. 20 is a hydraulic pressure at the beginning of application of the parking brake when the traveling operation lever is switched from the traveling stage to the stop stage. FIG. 21 is a block diagram showing the hydraulic system of the traveling drive mechanism, and FIG. 21 is a schematic diagram showing the configuration of the parking brake.

The hydraulic traveling drive mechanism of the present invention comprises two HSs.
That is, it is a two-pump, two-motor type hydraulic traveling drive mechanism composed of T, and is used, for example, in the crawler type transport vehicle shown in FIGS. 1 to 3. In this crawler type transport vehicle, a main frame 1 is provided with crawler traveling devices 2 and 2 formed by winding a crawler 2b on the left and right sides, and a cabin 3 on which an operator rides is provided at a front part on the main frame 1.
Is provided. A bonnet 4 having a fuel tank and the like installed therein is disposed on the side of the cabin 3, and is driven up and down by hydraulic lifting cylinders 6 shown in FIG. 3 behind the cabin 2 and the bonnet 4. A packing box 5 is provided.

The structure of the main frame 1 will be described with reference to FIGS. 3 to 6. The mainframe 1 is
The inner vertical frames 7L and 7R are arranged side by side in parallel with each other, and the outer vertical frames 8L and 8R are arranged parallel to each other on the outside thereof. These vertical frames 7L, 7R, 8L and 8R
Are connected by horizontal frames 9 in the left-right direction.

The engine, HST, and hydraulic hose piping for the HST will be described with reference to FIGS. 3 to 6. On the horizontal frame 1a of the main frame 1, an engine E is fixed near the center of the left and right and hydraulic pumps P1 and P are provided at the rear end thereof.
Two hydraulic motors M1 and M2 are fixedly provided on the left and right outer surfaces of the main frame 1, and the motor shafts of the hydraulic motors M1 and M2 are driven wheels of the left and right crawler traveling devices 2L and 2R. It is an axle of 2a, and is configured to rotate the drive wheel 2a and drive the crawler 2b.

The piping of the hydraulic hose between the pump and the motor will be described. Hydraulic motor M1 from hydraulic pump P1
, And hydraulic hoses H3 and H4 from the hydraulic pump P2 to the hydraulic motor M2, respectively, but the hydraulic hoses extending from the ports of the hydraulic pumps P1 and P2 are all lateral Is extended to the hydraulic hose H1
・ H2 is the left inner vertical frame 7L and the outer vertical frame 8
The hydraulic hoses H3 and H4 are arranged between the inner vertical frame 7R and the outer vertical frame 8R on the right side so as not to interfere with the engine E at all, and further support the engine E. In the horizontal frame 9, the insertion holes 9a are provided between the inner vertical frame 7L and the outer vertical frame 8L, and between the inner vertical frame 7R and the outer vertical frame 8R, respectively.
9a is bored, the hose pipes 10 and 10 are fitted into the respective fitting insertion holes 9a and 9a, and the hydraulic hoses H1 and H2 and the hydraulic hoses H3 and H4 are respectively inserted into the hose pipes 10 and 10. Through, they are connected to the ports of the hydraulic motors M1 and M2.

In such a hydraulic hose piping configuration, as in the conventional case, all hydraulic hoses are fan pulleys FP.
There is no part that intersects with the bottom of the engine or the like, and there is no part that interferes with the engine E or the fan pulley FP due to floating due to mud or the like. Then, by inserting the hydraulic hose into the hose pipe 10 inserted into the insertion hole 9a of the horizontal frame 9, the hydraulic hose does not bend downward and no exposed portion is generated, so that the hydraulic hose is caught by an object and damaged. That situation disappears.

Next, the inside of the cabin 3 will be described with reference to FIGS. 7 and 8. A rotatable seat base 1 in the cabin 3.
1 has a seat 12 mounted thereon, and the seat base 11
A traveling operation panel 11a is provided on the front portion of the
From there, left and right traveling operation levers L1 and L2 are provided so as to project above the front part. With the seat 12 facing forward, the left crawler traveling device 2L is driven by the left traveling operation lever L1 and the right crawler traveling device 2R is driven by the right traveling operation lever L2. 18
In the state where the seat 12 is turned backward by 0 ° and the seat 12 is directed rearward, the crawler traveling device 2R on the right side is operated by the traveling operation lever L1 on the left side and the traveling crawler traveling device 2R on the right side is operated by the traveling side operation lever L2 on the left side in order to match the driving feeling of the operator. It is switched to drive the crawler traveling device 2R. For this reason, a switching mechanism for the operation system according to the rotation of the seat base is provided, which will be described in detail later.

The traveling operation levers L1 and L2 are levers for operating the movable swash plates of the hydraulic pumps P1 and P2, and the output shaft (motor shaft) of the hydraulic motor is operated by operating the movable swash plates of the hydraulic pumps P1 and P2. The driving amount and the driving direction are changed, the traveling speed is adjusted by adjusting the driving amount, and the forward and backward switching is performed by changing the driving direction. The traveling operation levers L1 and L2 are rotatable forward and backward, and when the seat 12 is in the forward direction, the forward movement is performed when the seat 12 is tilted forward, and the backward movement is performed when the seat 12 is tilted backward. The crawler traveling device 1 is driven to travel (the reverse is true when the seat 12 is facing backward). When the hand is released, the motor returns to the neutral position (stop stage) and the motor drive is stopped. In addition, hereinafter, the forward stage or the reverse stage other than the stop stage will be referred to as “travel stage”.

The traveling operation levers L1 and L2 are structured so that they can be fixed in a forwardly leaned state. When the seat 12 is facing forward, it is fixed in the forward stage, and when it is facing backward, it is fixed in the reverse stage. Driving drive is maintained. That is, as shown in FIGS. 9 to 12, the traveling operation levers L1 and L
A movable plate 13 is fixedly provided on each base of the second member 2 and is rotated with the movement of the lever. A lateral fixed shaft 14 is fixed to the movable plate 13, and a fixed plate 15 is fixed to the traveling operation panel 11a between the bases of the traveling speed change levers L1 and L2. A shaft fitting member 15a having an arcuate shape in a side view is laterally fixed to the fixed plate 15, and when the traveling operation levers L1 and L2 are pivoted forward and set to a traveling stage, The fixed shaft 14 rotated along with it is naturally fitted into the shaft fitting member 15a, and the traveling operation levers L1 and L2 are fixed at the traveling stage. Traverse operation levers L1 and L
Since 2 can be fixed, traveling drive can be maintained even if the hand is released from the lever, and the burden on the operator is reduced. When the traveling operation levers L1 and L2 are tilted rearward,
The fixed shaft 14 easily comes off the shaft fitting member 15a,
The fixing of the lever at the traveling stage can be easily released, and the traveling operation levers L1 and L2 can be returned to the stop stage.

In the seat base 11, as shown in FIG.
The hub member 16 fixed to the lower end of the seat 12 is attached to the seat base 1
1. A rotary valve RV that is rotatably fitted around a shaft member 17 fixed to the lower end of the seat 1 is provided, and in the travel operation panel 11a at the front of the seat base 11, the travel operation lever is provided. A traveling operation valve SV is provided continuously from the base of L1 and L2.

A traveling stop lever 18 is pivotally supported on the left side surface of the traveling operation panel 11a so as to be rotatable forward and backward, and a main panel 19 disposed on the right side of the seat base 11 in the longitudinal direction. A travel stop button 20 is provided.
When the travel stop lever 18 is tilted forward or the travel stop button 20 is pressed, the travel operation levers L1 and L2 are not driven even if they are moved to the travel stage. This configuration will be described later in detail.

Under the above-described arrangement of levers, switches and valves, the traveling hydraulic system will be described with reference to FIGS.
It will be explained from 1. The swash plate control valves V1 and V2 are attached to the hydraulic pumps P1 and P2 that are connected to the engine E, and the hydraulic pumps P1 and V2 are switched by switching the swash plate control valves V1 and V2. Move the movable swash plate of P2 to the forward side or the reverse side (acceleration side or deceleration side), or
Control to stop is performed. The pilot pressure for switching the swash plate control valves V1 and V2 is obtained from the pilot pump PP that is connected to the hydraulic pump P2.
The hydraulic pumps P1 and P2 and the pilot pump P
The pump shaft of P shares the one extended from the output shaft of the engine E.

A pilot high pressure circuit 21 is piped from the pilot pump PP to the traveling operation valve SV, and the hydraulic system is branched by the traveling operation valve SV to perform traveling operation as shown in FIGS. 13 to 17. Pilot circuits 22a, 22 for swash plate control in which hydraulic oil supply is controlled by lever L1
b, the swash plate control pilot circuits 23a and 23b whose pressure oil supply is controlled by the traveling operation lever L2 are connected to the hub member 16 of the rotary valve RV, and the shaft member 17 of the rotary valve RV connects the swash plate. The control valve V1 is provided with swash plate control pilot circuits 24a and 24b, and the swash plate control valve V2 is provided with swash plate control pilot circuits 25a and 2a.
5b are connected. Then, as shown in FIGS. 14 and 15,
With the seat 12 facing forward, the rotary valve RV is used to control the swash plate control pilot circuits 22a.
b communicates with the swash plate control pilot circuits 24a and 24b, and communicates with the swash plate control pilot circuits 23a and 23b and the swash plate control pilot circuits 25a and 25b. In a state in which the swash plate control pilot circuits 22a and 22b are in communication with the swash plate control pilot circuits 25a and 25b, the swash plate control pilot circuits 23a and 23b and the swash plate control pilot circuit 24a. 24b communicates with each other, and as described above, the operated crawler traveling devices 2L and 2R can be reversed. Thus, the traveling operation levers L1 and L2 are
The pilot pressure is applied to the swash plate control valves V1 and V2 from the traveling operation valve SV whose opening and closing are controlled by the hydraulic pump P.
Operate the movable swash plate of 1 ・ P2 to move the hydraulic motor M1 ・ M
The drive control of 2 is performed.

Conventionally, the movable swash plate of the hydraulic pumps P1 and P2 and the traveling operation levers L1 and L2 were connected by a link or a rod, but in the present embodiment, the traveling operation lever L1 and L2.
L2 is for opening and closing the traveling operation valve SV, and a hydraulic hose for passing pilot pressure oil is provided between the traveling operation valve SV and the swash plate control valves V1 and V2 for switching the movable swash plate. Only by interposing, there is no mechanical transmission system such as links and rods.

Each of the hydraulic motors M1 and M2 is equipped with a parking brake. The drive structure of the parking brake will be described with reference to FIG. 21. The plate 2 is attached to the motor shaft 27 that is inserted into the speed reducer 26 by the hydraulic motor M.
8, a frictional plate 30 is fixed to the end of a piston rod 29a of a hydraulic parking brake cylinder 29, and the frictional plate 30 is moved by piston movement.
It can be crimped on and removed. When the pressure oil is discharged, the piston rod 29a slides downward, the friction plate 30 is pressed against the plate 28, and the motor shaft 27 integral with the plate 28 is formed.
Brake. Further, when pressure oil is sucked into the parking brake cylinder 29, the cylinder rod 29a slides upward, the friction plate 30 separates from the plate 28, and the parking brake is released.

Conventionally, this parking brake switching valve B
The switching operation of V'was performed by manual operation of the parking brake lever (parking brake lever) arranged on the main panel 19 or the like, but the manual operation leads to forgetting to apply the brake or incorrect use. In the present embodiment, the parking brake lever is switched by hydraulic pressure. That is, as shown in FIGS. 13 to 20, the parking brake pilot circuit 3 is connected to the pilot high voltage circuit 21.
1 is branched to supply pressure oil to the parking brake cylinders 29, 29 provided with the left and right hydraulic motors M1, M2. In the parking brake pilot circuit 31, a timer valve B which is a parking brake switching valve is provided.
Although the V is installed, the timer valve BV is provided with pilot circuits 22 and 23 connected to the travel operation valve SV.
The timer valve pilot circuit 33 is switched from 24.25 via the shuttle valve 32.32 by taking pilot pressure.

When the timer valve BV receives pilot pressure from the timer valve pilot circuit 33, it is switched to open the parking brake pilot circuit 31, but when the pilot pressure is stopped, the pressure from the parking brake cylinder 29 is changed. It is configured to gradually drain the oil. The switching of the timer valve BV is switched in conjunction with the operation of the traveling operation levers L1 and L2. This will be described with reference to FIGS. 18 to 20. FIG.
8 to 20, thick lines are high-voltage circuits, and thin lines are low-voltage circuits.

When the parking brake cylinder 2 shown in FIG. 18 is stopped, no pressure oil flows in the timer valve pilot circuit 33, the timer valve BV is closed, and the parking brake cylinder 2 is stopped.
The pressure oil in 9 is completely drained to the tank T, and the parking brake is applied.

Then, as shown in FIG. 19, the traveling operation lever L
When 1 · L2 is operated and set to the traveling stage, pilot pressure is generated in the timer valve pilot circuit 33, the timer valve BV is switched to the open state, pressure oil is sent to the parking brake cylinder 29, and the parking brake is released. To cancel. By the way, the shuttle valves 32 and 32 are installed,
Swash plate control pilot circuit 24a / 24b25c / 2
Even if the pressure oil flows to any of 5d, the pressure oil flows to the timer valve pilot circuit 33. That is, the parking brake is configured to be released regardless of whether the traveling operation levers L1 and L2 are operated, or whether the traveling brake is operated to the forward speed or the reverse speed, and the parking brake is released when the vehicle starts. The vehicle will start running smoothly.

As shown in FIG. 20, when the travel operation levers L1 and L2 are returned to the neutral position (stop stage), the timer valve BV switches to the state shown in FIG. 18, but at this time, the parking brake cylinder. Since the pressure oil is gradually released from the tank 29 to the tank T, the parking brake is gradually applied. That is,
Even if the travel control levers L1 and L2 are switched in conjunction with each other, it is dangerous if the parking brake is applied even when the travel control levers L1 and L2 are returned to the neutral position while traveling, and gradually. The safety is ensured by applying a hydraulic brake to the vehicle so that it can be braked gently.

Finally, the travel stop valve CV, which is a safety device that does not start even if the travel operation levers L1 and L2 are accidentally put in the travel stage, will be described. The travel stop valve CV is provided between the timer valve BV and the travel operation valve SV in the pilot high pressure circuit 21. Therefore, the parking brake is applied even when the travel stop valve CV is closed. The travel stop valve CV is an electromagnetic valve, and when the travel stop lever 18 or the travel stop switch 20 is turned on, the travel stop lever 18 or the travel stop switch 20 is switched to an open state so that the pilot high-voltage circuit 21 communicates with the travel operation lever L1.
The traveling operation by L2 is possible, but when the traveling stop lever 18 or the traveling stop switch 20 is turned off, the traveling stop valve CV is closed, and the pilot high voltage circuit 2
As a result, pressure oil is not supplied to the travel operation valve SV from 1, and the travel operation levers L1 and L2 cannot be traveled even if they are operated.

[0044]

Since the present invention is constructed as described above,
The following effects are obtained. That is, since it is configured as in claim 1, the movable swash plate of the hydraulic pump of the HST is controlled by the pilot pressure by the operation of the traveling operation lever, and is conventionally provided between the movable swash plate and the traveling operation lever. The link was
The mechanical transmission system such as the rod is eliminated, the vibration of the engine is not transmitted to the traveling operation lever, and it is not necessary to provide the vibration isolator, which leads to the cost reduction. In addition, since the movable swash plate operation is hydraulically controlled, the operation load of the traveling operation lever is lightened, and the burden on the operator is reduced. In addition, the deterioration of the operation caused by the trapping of earth and sand, which is a concern in the link and rod, does not occur, and stable operability can be secured for a long time. Since the parking brake is automatically activated and released based on the operation of the travel control lever, an accident may occur due to forgetting to apply the parking brake, or the parking brake may be damaged by applying the parking brake while driving. The adverse effect of erroneous operation of doing is also avoided. Further, when the vehicle is set from the stop stage to the traveling stage, the parking brake is gradually applied to avoid the risk of sudden stop.

Since the pilot hydraulic circuit can be easily closed by the switch operation, the supply of pilot pressure oil to the valve opened / closed by the travel operation lever is cut off. Despite being stopped,
Even if the drive lever is accidentally moved to the drive stage, the vehicle does not suddenly start and it is safe.

Further, since it is configured as in claim 3, the traveling operation lever need not be provided in front of and behind the seat as in the conventional case,
The work space is expanded, and it is possible to avoid the situation of hitting the lever at the time of rotation.Also, when the seat is rotated rearward due to the provision of the rotary valve, the same traveling operation lever can be used to move it to the opposite side from the front side. Since the traveling device can be driven and operated, it is easy to operate in accordance with the operation feeling of the operator.

Further, according to the present invention, since the traveling operation lever can be easily fixed to the traveling stage and the traveling drive can be maintained constant even if the hand is released from the lever, the conventional operation is not possible. It is possible to perform other operations while the vehicle is being driven, freeing the labor of fixing the lever to a fixed position by hand under posture and vibration, which greatly facilitates the traveling operation for the operator.

Further, since the fifth aspect is constructed, the HS
A situation in which the hydraulic hose between the hydraulic pump and the hydraulic motor at T can be piped without being provided with an intersecting portion and without being exposed, so that it can be caught on an object or interfere with an engine pulley or the like as in the past. Can be eliminated, hose damage can be greatly reduced, and a safe and reliable traveling vehicle can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a crawler-type carrier that employs a hydraulic traveling drive mechanism of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a bottom view of the same.

FIG. 4 is an engine, HST, in the mainframe 1.
FIG. 3 is a plan view showing an arrangement configuration of a hydraulic hose.

FIG. 5 is a side view of the same.

FIG. 6 is a front view of the same.

FIG. 7 is a side view of the cabin and its interior.

FIG. 8 is a perspective view from the upper rear side in the cabin.

FIG. 9 is a front view showing a configuration of travel operation levers L1 and L2.

FIG. 10 is a plan view of the same.

FIG. 11 is a side view of the same.

FIG. 12 is a perspective view showing a configuration in which a traveling operation lever can be fixed to a traveling stage.

FIG. 13 is a hydraulic circuit diagram of the hydraulic traveling drive mechanism of the present invention.

FIG. 14 is a block diagram showing a hydraulic system of a hydraulic traveling drive mechanism when the seat is facing forward.

FIG. 15 is a block diagram showing a communication structure of the rotary valve.

FIG. 16 is a block diagram showing a hydraulic system of a hydraulic traveling drive mechanism when the seat is facing rearward.

FIG. 17 is a block diagram showing a communication structure of the rotary valve.

FIG. 18 is a block diagram showing a hydraulic system of a hydraulic traveling drive mechanism when a parking brake is applied when traveling is stopped.

FIG. 19 is a block diagram showing a hydraulic system of a hydraulic traveling drive mechanism when a parking brake is released during traveling driving.

FIG. 20 is a block diagram showing a hydraulic system of a hydraulic travel drive mechanism at the beginning of application of a parking brake when a travel operation lever is switched from a travel stage to a stop stage.

FIG. 21 is a schematic diagram showing the configuration of a parking brake.

FIG. 22 is an engine in a conventional mainframe 1,
It is a top view which shows the arrangement structure of HST and a hydraulic hose.

FIG. 23 is a side view of the same.

FIG. 24 is a front view of the same.

[Explanation of symbols]

E Engine P1 ・ P2 Hydraulic pump PP Pilot pump M1 ・ M2 Hydraulic motor V1 ・ V2 Swash plate control valve L1 ・ L2 Travel operation lever H1 to H4 Hydraulic hose SV Travel operation valve BV Timer valve (parking brake switching valve) CV Travel stop Valve RV Rotary valve 1 Main frame 2 Crawler traveling device 2a Drive wheel 7 Inner vertical frame 8 Outer vertical frame 9 Horizontal frame 11 Seat base 12 Seat 13 Movable plate 14 Fixed shaft 15 Fixed plate 16 Hub member 17 Shaft member 18 Travel stop lever 20 Travel stop switch 21 Pilot high voltage circuit 22a / 22b to 25a / 25b Swash plate control circuit 29 Parking brake cylinder 31 Parking brake pilot circuit 32 Shuttle valve 33 Timer valve pilot circuit

Claims (5)

[Claims] 1. A traveling vehicle is provided with two HSTs, each HS
In the two-pump, two-motor hydraulic traveling drive mechanism that controls the driving of the left and right traveling devices one by one at T, a pilot hydraulic circuit is provided to perform the operation of the movable swash plate of the HST with the pilot pressure oil of the HST, In the pilot hydraulic circuit,
By providing a hydraulic valve that opens and closes by operating the travel operation lever, and further setting the travel operation lever to the travel stage,
A hydraulic traveling drive mechanism characterized in that when the parking brake is automatically released and is set from the travel stage to the stop stage, the parking brake is automatically applied gradually. 2. A traveling vehicle is provided with two HSTs, each HS
In the two-pump, two-motor hydraulic traveling drive mechanism that controls the driving of the left and right traveling devices one by one at T, a pilot hydraulic circuit is provided to perform the operation of the movable swash plate of the HST with the pilot pressure oil of the HST, In the pilot hydraulic circuit,
A hydraulic traveling drive mechanism comprising: a hydraulic valve that opens and closes by operating a travel operation lever; and a hydraulic valve that opens and closes by operating a switch on the upstream side thereof. 3. A traveling vehicle is provided with two HSTs, each HS
In the two-pump, two-motor hydraulic traveling drive mechanism that controls the driving of the left and right traveling devices one by one at T, a pilot hydraulic circuit is provided to perform the operation of the movable swash plate of the HST with the pilot pressure oil of the HST, In the pilot hydraulic circuit,
A hydraulic travel drive characterized in that a hydraulic valve that opens and closes by operating a travel operation lever and a rotary valve that switches as the seat rotates are provided, and the travel operation lever rotates integrally with the seat. mechanism. 4. A traveling vehicle is provided with two HSTs, each HS
In the two-pump, two-motor type hydraulic traveling drive mechanism for driving and controlling the left and right traveling devices one by one at T, one traveling operation lever is provided for operating the movable swash plate of each HST,
A hydraulic traveling drive mechanism comprising a fixing member which can be fixed at a traveling stage and easily released. 5. A traveling vehicle is provided with two HSTs, each HS
In the two-pump, two-motor hydraulic traveling drive mechanism that controls the driving of the left and right traveling devices one by one at T, both HSTs are arranged in the main frame of the vehicle, and the hydraulic pressure between the hydraulic pump and the hydraulic motor in each HST is set. A hydraulic traveling drive mechanism characterized in that a hose is fitted into a fitting hole formed in a lateral frame of the main frame and piped.