JP2003041629A - Parking-brake hydraulic circuit for slewing base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the movement of a swivel base on the completion of the operation of a front attachment. SOLUTION: A brake-release cylinder 19 for a hydraulic motor 3 for a slewing is controlled by an on-off valve 45 with the second pilot chamber 47 in which pilot pressure is changed in response to the operation of direction changeover valves 14, 12a, 12b, 13a and 13b for the front attachment and the first pilot chamber 46 in which pilot pressure is changed by the operation of a slewing operating device 18. The cylinder 19 instantaneously releases a brake for the motor 3 in the operation of the direction changeover valves for the front attachment and the operating device 18, and the motor 3 is stopped and the brake is applied to the motor 3 by a throttling 43 in the case of the completion of the operation of the operating device 18, but the cylinder 19 instantaneously applies the brake to the motor 3 on the completion of the operation of the direction changeover valves for the front attachment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning parking brake for a construction machine such as a hydraulic excavator, and more particularly to a brake releasing cylinder for releasing braking of a rotary shaft of a turning hydraulic motor by supplying pressure oil. The present invention relates to a parking brake hydraulic circuit for turning in a hydraulic circuit device of a construction machine having a mechanical brake device.

[0002]

2. Description of the Related Art FIG. 9 is a circuit diagram showing an example of a conventional parking brake hydraulic circuit for a construction machine. Reference numerals 1 and 2 are main hydraulic pumps, 1a and 2a are pressure oil supply lines, and 1b and 2b. Is a center bypass pipe line, 3 is a turning hydraulic motor, 3a is a rotary shaft, 4 is a left traveling hydraulic motor, 5 is a right traveling hydraulic motor, 6 is a boom cylinder, 7 is an arm cylinder, and 8 is a hydraulic cylinder.
Is a bucket cylinder, 9 is a directional valve for turning, and 12
Reference characters a and 12b are boom direction switching valves, 13a and 13b are arm direction switching valves, 14 is a bucket direction switching valve, 15 is a mechanical brake device, 16 is a spare direction switching valve, and 17a to 17j are tanks. , 18 is an operating device for turning, 18a is an operating lever, 18b is a pilot pump, 18c is a pressure oil supply pipe line, 18d is a return pipe line, 18
e and 18f are pilot valves, 18g is a relief valve, 18
h and 18i are pilot lines, 19 is a brake release cylinder, 19a is a cylinder chamber, 19b is a spring member, and 19c.
Is a brake member, 20 is a brake circuit device, 21 is a check valve, 22 is a throttle, 23 is a relief valve device, 24 is a pilot line, 31 is an auxiliary hydraulic pump, 32 is a control circuit,
Reference numeral 33 is a second control pipeline, and 34 is a first control pipeline.

In FIG. 1, this hydraulic circuit device is provided with two main hydraulic pumps 1 and 2, and by supplying pressure oil from these main hydraulic pumps 1 and 2, the turning hydraulic motor 3 and the left traveling hydraulic motor are provided. The motor 4, the hydraulic motor 5 for traveling to the right, and the cylinder for operating the front attachment, that is, the boom cylinder 6, the arm cylinder 7, the bucket cylinder 8
And so on. Then, a direction switching valve for switching the flow rate and flow direction of the pressure oil for driving these, that is, a direction switching valve 9 for turning and a direction switching valve 10 for left traveling.
And direction switching valve 11 for right traveling and direction switching valve 1 for boom
2a, 12b, directional control valves 13a, 13b for arms, directional control valve 14 for buckets, and a spare directional control valve 16 are provided.

The main hydraulic pump 1 is connected to a pressure oil supply line 1a for receiving the pressure oil that is taken in from the tank 17a and supplied by the main hydraulic pump 1, and this pressure oil supply line 1a is connected.
Are the directional control valves 9, 13a, 12a, 16, 1 described above.
It is connected to a center bypass pipe line 1b which sequentially passes through 0 to reach the tank 17b. This center bypass line 1b
Is the input port 9 in the directional control valve 9 for turning.
It is also connected to the input port of the other directional control valves 13a, 12a, 16 and 10 in the same manner, but it is omitted here. Further, the output port 9b of the turning directional valve 9 is connected to the return line 1b reaching the tank 17b, and similarly, the output ports of the directional control valves 13a, 12a, 16 and 10 are also connected to the tank 17b. Although not shown here, they are connected to the individual return pipes up to.

The main hydraulic pump 2 is also connected to a pressure oil supply line 2a for receiving the pressure oil that is taken in and supplied from the tank 17c, and this pressure oil supply line 2a is connected.
Is the center bypass pipe line 2b which passes through the above-mentioned directional control valves 11, 14, 12b and 13b in order and reaches the tank 17d.
It is connected to the. This center bypass line 2b is also connected to the input ports of these directional control valves 11, 14, 12b, 13b, and these directional control valves 11, 1 are also connected.
The output ports of 4, 12b, and 13b are connected to the return pipes that reach the tank 17d, but they are not shown here.

A turning hydraulic motor 3 is connected to the turning direction switching valve 9 via a relief device 23. Similarly, the left traveling direction switching valve 10 is connected to the left traveling hydraulic motor 4, and the right traveling direction switching valve 11 is connected to the right traveling hydraulic motor 5. Further, each of the directional control valves for the front attachment, that is, the directional control valve 14 for the bucket has the bucket cylinder 8, the directional control valves 12a and 12b for the boom have the boom cylinder 6, and the directional control valve for the arm has the boom cylinder 6. An arm cylinder 7 is connected to each of the direction switching valves 13a and 13b.

A drive gear 3c is mounted on the rotary shaft 3a of the turning hydraulic motor 3 through a speed reducer 3b in a known manner, and an internal gear of a turning base (not shown) meshes with the drive gear 3c. ing.

Further, the turning hydraulic motor 3 is provided with a mechanical brake device 15 for acting on the rotary shaft 3a to brake the turning hydraulic motor 3. The mechanical brake device 5 includes a brake release cylinder 19 that operates by hydraulic pressure.
The brake releasing cylinder 19 is composed of a cylinder chamber 19a, a spring member 19b, and a brake member 19c. When pressure oil is not supplied to the cylinder chamber 19a, the brake member 19b causes the brake member 19c to rotate. Although the brake is running on, when the pressure oil is supplied into the cylinder chamber 19a, the oil pressure is changed to the spring member 1.
The brake member 19c is disengaged from the rotary shaft 3a of the turning hydraulic motor 3 against the biasing force of 9b, and the brake of the turning hydraulic motor 3 is released.

Therefore, this hydraulic circuit device is also provided with a brake circuit device 20 for operating the mechanical brake device 15, and hence the brake release cylinder 19. The brake circuit device 20 includes an auxiliary hydraulic pump 31 that outputs pressure oil, a control circuit 32 that controls the supply of pressure oil from the auxiliary hydraulic pump 31 to the brake release cylinder 19 of the mechanical brake device 15, and a brake release cylinder. The control circuit 32 includes a pilot line 24 connected to the cylinder chamber 19a of the reference numeral 19, a check valve 21, and a throttle 22. The control circuit 32 receives a pressure oil supplied from the auxiliary hydraulic pump 31. 31a,
It is composed of a second control pipeline connected to the pressure oil supply pipeline 31a and a first control pipeline 34. The second control line 33 is connected to the cylinder chamber 19a of the brake release cylinder 19 via the check valve 21 and the throttle 22. In addition, the first control line 34 is provided for each directional control valve 1
4, 12b, 13b, 9, 13a, 12a, 16 to reach the tank 17f, and a partial conduit 34a that connects the pressure oil supply conduit 31a with the pilot input port 14a of the direction switching valve 14 and this direction A partial pipeline 34b that connects the pilot output port 14b of the switching valve 14 and the pilot input port 12c of the directional switching valve 12b, the pilot output port 12d of the directional switching valve 12b, and the pilot input port 13c of the directional switching valve 13b. The partial conduit 34c communicating with the pilot output port 13d of the directional switching valve 13b and the pilot input port 9e of the directional switching valve 9 with the partial conduit 34d communicating with the directional switching valve 9d.
Of the pilot output port 9f and the pilot input port 13e of the directional control valve 13a for communicating with each other
And the pilot output port 13 of this directional control valve 13a
a partial conduit 34f that communicates f with the pilot input port 12e of the direction switching valve 12a, and a partial conduit 34g that communicates the pilot output port 12f of this direction switching valve 12a with the pilot input port 16a of the direction switching valve 16 ,
The directional control valve 16 includes a pilot output port 16b and a partial conduit 34h that connects the tank 17f.

The turning direction switching valve 9 operates according to the operation of the operating device 18 of the turning hydraulic motor 3, and controls the flow rate and the flow direction of the pressure oil to the turning hydraulic motor 3. Similarly, the left and right traveling direction switching valves 10 and 11 also operate in accordance with the operation of an operating device (not shown) to control the flow rate and flow direction of the pressure oil to the left and right traveling hydraulic motors 4 and 5. Directional switching valves 14, 12a, 12 for front attachment
b, 13a, and 13b also operate according to the operation of an operating device (not shown), and the front attachment cylinder 8,
Control the flow rate and direction of pressure oil to 6 and 7. These direction change valves 9, 10, 11, 14, 12a, 12b, 1
3a and 13b are in the neutral position when the operating device is not operated.

Directional changeover valve 9 for turning and direction changeover valves 14, 12b, 13b, 9, 13 for front attachment.
a and 12a, when they are in the neutral position, their pilot input port and pilot output port are in communication. For example, when the turning direction switching valve 9 is in the neutral position, the pilot input port 9e and the pilot output port 9f communicate with each other.

Therefore, these directional control valves 14, 12b,
None of 13b, 9, 13a, 12a is operated,
When all are in the neutral position (however, the directional control valve 16
Is always set to the neutral position as long as it is a spare). Since all these pilot input ports and pilot output ports communicate with each other, the pressure oil from the auxiliary hydraulic pump 31 is supplied with the pressure oil. It is discharged to the tank 17f through the pipeline 31a and the first control pipeline 34. Due to the flow of the pressure oil, no pressure is applied to the second control conduit 33, and the pressure oil does not flow into the second control conduit 33. Therefore, at this time, the pressure oil is not supplied to the cylinder chamber 19a of the brake releasing cylinder 19, and the turning hydraulic motor 3 is in the braked state.

Direction switching valves 14, 12b, 13b, 9, 1
Even if any one of 3a and 12a is operated, for example, when the directional control valve 13b for the arm is operated and is no longer in the neutral position,
That is, even if the neutral position slightly changes, the space between the pilot input port 13c and the pilot output port 13d of the directional control valve 13b is cut off, and the pressure oil does not flow into the first control line 34. For this reason, pressure is applied to the second control pipe 33, and the pressure oil from the auxiliary hydraulic pump 31 flows through the pressure oil supply pipe 31a.
In this way, when the pressure rises in the second control line 33, the check valve 21 is immediately opened, and the pressure oil is immediately supplied into the cylinder chamber 19a of the brake release cylinder 19. For this reason, the brake release cylinder 19 is immediately actuated, and the brake member 19c is removed from the rotary shaft 3a of the turning hydraulic motor 3 to bring the brake release state. Here, to immediately release the brake means to bring the brake release state before the turning hydraulic motor 3 starts to rotate.

In this case, the brake release cylinder 1
When the pressure oil is sufficiently supplied into the cylinder chamber 19a of the cylinder 9 and cannot be further supplied, the relief valve 31b is operated and the pressure oil from the auxiliary hydraulic pump 31 is supplied to the tank 17
to i.

Thereafter, the directional control valve 13b for this arm is used.
When the operation is stopped and the directional control valve 13b returns to the neutral position, the pilot input port 13c and the pilot output port 13d of the directional control valve 13b communicate with each other, and the entire first control conduit 34 communicates with each other. Therefore, the auxiliary hydraulic pump 31
The pressure oil from the first control line 3 is supplied from the pressure oil supply line 31a.
4 and flows into the tank 17f (at this time, the relief valve 31b is closed). As a result, no pressure is applied to the second control line 33, the oil in the cylinder chamber 19a of the brake release cylinder 19 flows through the throttle 22, and the oil flows from the second control line 33 to the first control line 34. Although it flows in and is discharged (at this time, the check valve 21 is closed due to the reverse pressure), the action of the throttle 22 causes the cylinder chamber 19 of the brake release cylinder 19 to be released.
The oil in a is not removed suddenly, but will be removed over time. For this reason, even if the directional control valve 13b is finished operating and returns to the neutral position, the brake release cylinder 19 does not operate immediately, and the turning hydraulic motor 3 is braked after a predetermined time has elapsed. become.

The mechanical brake device 15 protects the brake release cylinder 19 and the like that compose the mechanical brake device 15,
The brake is applied while the turning hydraulic motor 3 is stopped. That is, the turning hydraulic motor 3
When the vehicle starts rotating, the mechanical brake device 1
5 is released to release the brake of the turning hydraulic motor 3, and when the turning hydraulic motor 3 stops rotating, the rotation is surely stopped, and then the mechanical brake device 15 brakes the turning hydraulic motor 3. Try to apply Therefore, as described above, the check valve 21 and the throttle 22 are provided between the second control line 33 and the cylinder chamber 19a of the brake release cylinder 19, and the second control line 3 is provided.
When the pressure is applied to 3, the check valve 21 is activated immediately so that the pressure oil is supplied to the cylinder chamber 19a, and when the pressure in the second control line 33 is exhausted, the throttle 2
2 operates to discharge the pressure oil in the cylinder chamber 19a over time. The discharge time, that is, the time from the start of the discharge until the mechanical brake device brakes the turning hydraulic motor 3 is set to, for example, about 3 to 4 seconds.

By the way, when a front attachment such as a bucket, a boom or an arm is operated to perform a work, a large force for rotating the swivel base may be applied depending on the state of the work. In such a case, a large rotational force is applied to the rotary shaft 3a of the turning hydraulic motor 3, but at this time, if the rotary shaft 3a is braked by the mechanical brake device 15, the speed reducer 3b is applied. A large force is applied, and the speed reducer 3b and the like may be destroyed. In order to prevent this, not only when the turning hydraulic motor 3 is rotated, but also in the direction switching valves 14, 12a, 12b, 13
The brake of the turning hydraulic motor 3 must also be released when operating the a and 13b and changing the neutral position to operate the front attachment.

For this purpose, the first control line 34 is provided not only for the turning direction switching valve 9 but also for the front attachment direction switching valves 14, 12a, 12b, 13a, 13b.
And the brake release cylinder 19 is operated when any of these is operated to change from the neutral position.
The mechanical brake device 15 releases the brake of the turning hydraulic motor 3 by supplying pressure oil to the cylinder chamber 19a.

Here, the operation device of each directional control valve will be described by taking the one for the directional control valve 9 for turning as an example.

The operating device 18 is for operating the directional control valve 9 for turning, and has an operating lever 18a.
And pilot valves 18e and 18f controlled according to the operation of the operating lever 18a, and the pilot valves 18e and 18f.
e, 18f and the return line 18d that connects the tank 17h
, Pilot pump 18b and pilot valves 18e, 1
8f is provided with a pressure oil supply conduit 18c and a pressure oil supply conduit 18c is communicated with the tank 17j, a relief valve 18g is provided, and the pilot valve 18e is provided with a pilot conduit 1
8i is connected to the pilot operating portion 9c of the direction switching valve 9, and the pilot valve 18f is connected to the pilot operating portion 9d of the direction switching valve 9 via the pilot conduit 18h.

In such a construction, when the operating lever 18a is in the neutral position, the pilot valves 18e, 18f.
Both communicate with the return pipe 18d, and the pressure oil of the pilot operating portions 9c, 9d of the direction switching valve 9 is discharged to the tank 17h via the pilot pipes 18i, 18h and the pilot valves 18e, 18f. It will be. Further, the pressure oil pumped up from the tank 17g by the pilot pump 18b is the pressure oil supply pipe line 18c and the relief valve 18
It is discharged to the tank 17j via g. At this time, in the directional control valve 9, pressure is not generated in the pilot operating portions 9c and 9d, so that it is set to the neutral position.

If the operating lever 18a is operated in the W direction in such a state, the pilot valve 18f remains connected to the return line 18d, but the pilot valve 18e remains in the pressure oil supply line. 18c. Therefore, the tank 17g
The pressure oil taken in from is supplied to the pilot operating portion 9c of the direction switching valve 9 through the pressure oil supply pipe line 18c, the pilot valve 18e, and the pilot pipe line 18i. As a result, in the direction switching valve 9, the pilot operating parts 9c, 9
A pressure difference occurs between d and the neutral position is switched to the first operating position. In the first operating state, the pressure oil in the center bypass pipe 1b flows from the input port 9a through the direction switching valve 9 in the first direction and is supplied to the turning hydraulic motor 3. At this time, since the direction switching valve 9 has changed from the neutral position, the mechanical brake operation 15 releases the brake of the turning hydraulic motor 3 as described above. As a result, the turning hydraulic motor 3 starts rotating in the first direction.
The pressure oil that has passed through the turning hydraulic motor 3 passes through the direction switching valve 9, and is further discharged from its outlet port 9b through the return passage 1c to the tank 17b. The relief device 2
3 is for making the pressure applied to the turning hydraulic motor 3 constant by the pressure oil.

When the operating lever 18a of the operating device 18 is operated in the direction opposite to the W direction, the pilot valve 18e is connected to the return line 18d and the pilot valve 18f is connected to the pressure oil supply line 18c. Therefore, similarly, the pressure oil is supplied to the pilot operating portion 9d of the direction switching valve 9, and the direction switching valve 9 moves from the neutral position to the second operating position different from the first operating position. Is switched to. As a result, similarly to the above, the pressure oil that has passed through the inside of the direction switching valve 9 from the inlet port 9a flows in the second direction opposite to the first direction and is supplied to the turning hydraulic motor 3. The turning hydraulic motor 3 starts to rotate in a second direction opposite to the first direction.

Although separate tanks 17a to 17j are used here for convenience of explanation, they are the same tank. In addition, the auxiliary hydraulic pump 31 and the pilot pump 18
b is the same hydraulic pump.

[0025]

By the way, according to the above-mentioned prior art, even when the operation of the attachment is completed,
Immediately the mechanical brake device 15 turns the turning hydraulic motor 3
Instead of applying the brake, the brake is applied after a certain amount of time has passed since the throttle 22 acts, as when the swing hydraulic motor 3 stops.

Therefore, for example, when performing work on a sloping ground, not only when operating only the front attachment, but also when the front attachment is stopped, the swivel base is stopped. There may be a case where an undesired rotational force is applied to. During work, even if a large rotational force is applied to the swivel base, the hydraulic motor 3 for swivel is not braked, and even if the swivel base moves due to the rotational force applied to the swivel base, this movement does not occur. Since it can be operated so as to be adjusted, it does not cause a problem for each, but it may be very dangerous if the swivel moves when the operation of the front attachment is stopped. As described above, if the turning hydraulic motor is not braked for a certain period even if the front attachment is stopped, such a dangerous situation may possibly occur.

An object of the present invention is to solve the above problem and to provide a turning stop brake hydraulic circuit capable of preventing the turning base from moving when the operation of the front attachment is completed.

[0028]

In order to achieve the above object, the present invention releases a brake of a turning hydraulic motor by operating at least one of a front attachment operating device and a turning operating device. However, when all of these operating devices are set to the neutral position, the turning parking brake hydraulic circuit includes a brake releasing cylinder that brakes the turning hydraulic motor, and has a first pilot chamber and a second pilot chamber. , When pressure oil is supplied to the first and second pilot chambers, the first pilot line connected to the brake release cylinder is connected to the second pilot line connected to the hydraulic pump. By supplying pressure oil to the brake release cylinder, the brake of the turning hydraulic motor is released, and when the pressure oil is discharged from the first and second pilot chambers, the breaker is released. An on-off valve that brakes the turning hydraulic motor by switching the first pilot line connected to the release cylinder to a tank and discharging pressure oil from the brake release cylinder; and at least the front valve. A first control line for detecting the state of the directional control valve for attachment; and a second control line for communicating between the first control line and the first pilot chamber of the release valve. The second control line from the hydraulic pump to the release valve when the first control line detects that at least one of the directional control valve for the front attachment is in the actuated position. Supplying pressure oil to the first pilot chamber,
When the first control line detects that all of the directional control valves for the front attachment are in the neutral position, the first valve for discharging the pressure oil in the first pilot chamber of the opening valve to the tank Control circuit and a third control line are connected to the second pilot chamber of the opening / closing valve via a check valve and a throttle, and when the operating device of the turning hydraulic motor is operated, Pressure oil from the pump is supplied to the second pilot chamber of the on-off valve via the third control line and the check valve, and when the operation of the operating device is completed, A second control circuit for discharging the pressure oil in the second pilot chamber to the tank through the throttle and the third control pipe, and returning all the directional control valves for the front attachment to the neutral position. The brake release cylinder operates from the turning oil The time until the brake is applied to the motor is shorter than the time from the end of the operation of the operating device of the turning hydraulic motor to the operation of the brake release cylinder to apply the brake to the turning hydraulic motor. It is configured in.

Further, according to the present invention, similarly, the first and second
Second pilot chamber having a pilot chamber, and when hydraulic oil is supplied to the first and second pilot chambers, a first pilot line connected to the brake release cylinder is connected to a hydraulic pump. The brake of the turning hydraulic motor is released by being connected to a pipe line and supplying pressure oil to the brake release cylinder. When the pressure oil is discharged from the first and second pilot chambers, the brake release is performed. An on-off valve that brakes the turning hydraulic motor by switching the first pilot line connected to the cylinder to a tank and discharging pressure oil from the brake releasing cylinder;
At least one of the operating devices for the front attachment is connected to a hydraulic circuit of the operating device for the front attachment, and when at least one of the operating devices for the front attachment is operated, pressure oil is supplied from the hydraulic pump to the first pilot chamber of the release valve. A first control circuit for discharging the pressure oil in the first pilot chamber of the opening valve to the tank and supplying a third control line when the operation of the operation device for the front attachment is completed. Is connected to the second pilot chamber of the on-off valve via a check valve and a throttle, and when the operating device of the turning hydraulic motor is operated, pressure oil from a hydraulic pump is supplied to the third control unit. It is supplied to the second pilot chamber of the on-off valve via a pipe and the check valve, and when the operation of the operating device is completed, the pressure oil in the second pilot chamber of the on-off valve is throttled. And the And a second control circuit for discharging to the tank via the control pipeline of No. 3, and after returning all the direction switching valves for the front attachment to the neutral position, the brake release cylinder is operated to operate the turning hydraulic motor. The time until the brake is applied is shorter than the time from the end of the operation of the operating device for the turning hydraulic motor to the time when the brake release cylinder is activated and the brake is applied to the turning hydraulic motor. It is composed. And
Further, in these inventions, instead of the throttle, a pressure compensating valve that maintains a constant flow rate of the pressure oil regardless of temperature change is used.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a first embodiment of a parking brake hydraulic circuit for turning according to the present invention.
7k is a tank, 35 is a control circuit, 40 is a shuttle valve, 4
1 is a third control line, 42 is a check valve, 43 is a throttle,
44 is a pilot line, 45 is an on-off valve, 45a is a first position, 45b is a second position, 45c is a spring member, 46 is a first pilot chamber, 47 is a second pilot chamber, 48
Is a pilot pipe line, and 49 is a cylinder control device. The parts corresponding to those in FIG.

In the prior art shown in FIG. 9, the control circuit 32
Although the pressure rising in the second control line 33 of the cylinder control device is used directly for controlling the brake release cylinder 19, in the first embodiment, as shown in FIG.
Is provided so that the brake release cylinder 19 is controlled.

The cylinder control device 49 includes a directional control valve 14, 12a, 12b, 1 for front attachment.
3a and 13b are operated, and also when the turning direction switching valve 9 is operated by the operating device 18, pressure oil is immediately supplied to the cylinder chamber 19a of the brake release cylinder 19 so that the turning hydraulic motor 3 operates. Allow the brakes to be released immediately.

However, in this case, "immediately" means that when the operating device 18 is operated to start the rotation of the turning hydraulic motor 3, as described above, the turning hydraulic motor is actually operated. That is, before the time equal to the time required for 3 to start rotating has elapsed. Below, the time required for releasing the brake of the turning hydraulic motor 3 by operating the brake releasing cylinder 19 after operating the operating device 18 is the required brake releasing time Tc.
I will decide.

Further, when the operation of the turning direction switching valve 9 is finished and returned to the neutral position, at this time, the front attachment direction switching valves 14, 12a, 12b, 13 are returned.
If a and 13b are all in the neutral position, the cylinder control device 49 delays the start of the pressure oil discharge from the cylinder chamber 19a and brakes the turning hydraulic motor 3 as in the conventional example described in FIG. The brake release cylinder 19 brakes the turning hydraulic motor 3 after the turning hydraulic motor 3 which has been rotationally driven until now is surely stopped. The brake start delay time for this purpose will be referred to as a required brake delay time Tb hereinafter), and the directional control valves 14, 12a, 12 for the front attachment.
b, 13a, 13b are finished and returned to the neutral position. At this time, when the turning direction switching valve 9 is in the neutral position, the pressure oil is immediately discharged from the cylinder chamber 19a to turn the turning hydraulic motor. The brake should be applied immediately to item 3.

However, "immediately" in this case does not necessarily mean that the directional control valve 1 for such a front attachment is used.
It may be at the same time when 4, 12a, 12b, 13a, 13b return to the neutral position, but not only this, but also the required brake delay time Tb when the directional control valve 9 for turning is returned to the neutral position. Shorter time than that. In this embodiment, the directional control valve 1 for the front attachment
4, 12a, 12b, 13a, 13b is returned to the neutral position, the time until the brake is applied to the turning hydraulic motor 3 is made shorter than the required brake delay time Tb. Is referred to as shortened brake delay time Trb. This shortened brake delay time Tsb is
The time may be 0 seconds as long as it is shorter than the required brake delay time Tb.

Next, the first embodiment will be described.

In FIG. 1, the brake release cylinder 19
On the other hand, a cylinder control device 49 for controlling this is provided. The cylinder control device 49 is composed of an opening / closing valve 45 having first and second pilot chambers 46, 47, and the opening / closing valve 45 includes pilot lines 44, 4
8 is arranged between the pilot pump 18b and the brake release cylinder 19. The second control line 33 is connected to the second pilot chamber 47 of the opening / closing valve 45. In addition, the pilot conduit 18 from the operating device 18
shuttle valve 40 connected between h and 18i, a third control line 41 connected to this shuttle valve 40, a check valve 42 and a throttle 43 connected to this third control line 41 (this May be a throttle valve. The same shall apply hereinafter) form a control circuit 35, and the check valve 42 and throttle 43 of this control circuit 35 are connected to the first pilot chamber 46 of the opening / closing valve 45. There is. The above configuration constitutes the brake circuit device.

When no pressure oil is supplied to the first and second pilot chambers 46 and 47 and pressure does not rise there, the opening / closing valve 45 is opened by the urging force of the spring member 45c. The position (neutral position) 45a is set. At the first position 45a, the pilot line 48 connected to the brake release cylinder 19 is communicated with the tank 17k, and the pilot line 44 connected to the pilot pump 18b is shut off by the opening / closing valve 45. Also, the first
When pressure oil is supplied to at least one of the second pilot chambers 46 and 47 and a pressure rises there, this pressure overcomes the biasing force of the spring member 45c and the open / close valve 45 switches to the second position, so that the pilot pipe The paths 44 and 48 communicate with each other.

In this structure, the directional control valves 14, 12a, 12b, 13 for the front attachment are now available.
When at least one of a and 13b is operated, as in the conventional example shown in FIG. 9 above, a pressure rises in the second control conduit 33, and the pilot pump 31 moves the second valve of the on-off valve 45 to the second position.
The pressure oil is supplied to the pilot chamber 47 of the. As a result, pressure is generated in the second pilot chamber 47, and this pressure causes the on-off valve 45 to move to the second position against the biasing force of the spring member 45c.
Position 45b. At this time, the operation portion 18 is not operated, and the pressure oil is not supplied to the first pilot chamber 46 of the opening / closing valve 45, as described later.

In this way, when the on-off valve 45 is set to the second position 45a, the pilot lines 44 and 48 are connected to the on-off valve 45, and the pilot pump 18b is immediately connected to the pilot lines 44 and 48. The pressure oil is supplied to the cylinder chamber 19a of the brake release cylinder 19 via. Thereby, the directional control valves 14, 12a, 12
With the operation of b, 13a, 13b, the brake of the turning hydraulic motor 3 is released within the required brake release time Tc.

After that, the directional control valves 14, 12a, 12
When the operation of the directional control valve that has been operated among b, 13a, and 13b is completed, the pressure in the second control line 33 disappears as in the conventional example shown in FIG. The pressure oil in the second pilot chamber 47 of the valve 45 is immediately discharged to the tank 17f through the second and first control pipes 33 and 34, and at the same time, the opening / closing valve 45 is urged by the urging force of the spring member 45c. Switches from the second position 45b to the first position (neutral position) 45a. As a result, the pilot line 44 is shut off by the on-off valve 45, the pilot line 48 communicates with the tank 17k, and the pressure oil in the cylinder chamber 19a of the brake release cylinder 19 is immediately discharged to the tank 17k.

In this way, the directional control valves 14, 12 are
When the operation of the directional control valve, which has been operated among a, 12b, 13a, and 13b, is completed, the brake release cylinder 19 applies the brake to the turning hydraulic motor 3 within the shortened brake delay time Trb.

Next, when the operating device 18 is operated while the on-off valve 45 is in the neutral position (first position 45a), the turning direction switching valve 9 is operated, so that the above-mentioned front is operated. Directional switching valves 14, 12a, 1 for attachment
The pressure oil is supplied to the second pilot chamber 47 of the on-off valve 45 as in the case where 2b, 13a and 13b are operated.
At the same time, the pilot valve 18e or 18f in the operating device 18 is actuated, and the pilot conduits 18i, 18h
Since the pressure oil flows to either one of the above, a part of this pressure oil flows into the third control pipe 41 via the shuttle valve 40, and further, via the check valve 42, the first opening / closing valve 45. It is supplied to the pilot chamber 46. This makes the first
In the pilot room 46 (also the second pilot room 47
Also, a pressure is generated, and this pressure causes the spring member 45c.
The on-off valve 45 switches to the second position 45b against the urging force of. As a result, in the on-off valve 45, the pilot lines 44 and 48 are connected, and the pressure oil is supplied from the pilot pump 18b to the cylinder chamber 19a of the brake release cylinder 19 via the pilot lines 44 and 48. In this way, even when the operating device 18 is operated, the turning hydraulic motor 3 is operated for the required brake release time Tc in accordance with the operation.
The brake will be released.

After that, when the operation of the operating device 18 is completed, the pressure in the second control line 33 also disappears in this case, so that the pressure oil in the second pilot chamber 47 of the on-off valve 45 immediately changes to the control line. It is discharged to the tank 17f via the paths 33 and 34. The pressure oil in the first pilot chamber 46 is also discharged to the tank 17h of the operating device 18 via the shuttle valve 40. Since the discharge passage is provided with the throttle 43, the discharge is performed as described above. It will take a long time. After this time elapses, the on-off valve 45 is moved to the first position (neutral position) 45a by the urging force of the spring member 45c.
Returning to the above, the pilot line 48 is connected to the tank 1 as described above.
The pressure oil in the cylinder chamber 19a of the brake release cylinder 19 is discharged to the tank 17k in communication with the 7k.

In this way, when the operation of the operating device 18 is completed, after the required brake delay time Tb has elapsed, the brake is applied to the turning hydraulic motor 3 by the brake release cylinder 19.

As described above, in the first embodiment,
When all the operations of the front attachment directional control valve are completed, the brake is immediately applied to the turning hydraulic motor 3 to solve the above problems, and the directional control valve 9 for turning is also used. When the operation is finished, the brake is driven to the turning hydraulic motor 3 after the required brake delay time Tb has elapsed, so the brake should be applied after the turning hydraulic motor 3 is reliably stopped. Can be applied and brake release cylinder 1
It is possible to prevent a failure of the mechanical brake device 15 such as a breakage of the mechanical brake 9.

FIG. 2 is a circuit diagram showing a second embodiment of the turning parking brake hydraulic circuit according to the present invention, in which 17 is a tank, 50 is an engine, 51 is an arm operating device, 5
2 is an operating device for the left traveling hydraulic motor 4 (left traveling hydraulic motor operating device), 53 is an operating device for the right traveling hydraulic motor 5 (right traveling hydraulic motor operating device), 54 is a boom operating device, and 55 is a bucket. The operation device, 56 is a pilot pump, and 57 is a throttle. The parts corresponding to those in FIG.

This second embodiment is basically the same as that shown in FIG.
The embodiment has the same configuration as that of the embodiment shown in FIG. 4 and also shows an operating device for a motor other than the turning hydraulic motor and a front attachment.

In the figure, the pilot pump 56 is
Auxiliary hydraulic pump 31 and pilot pump 1 in FIG.
It also serves as 8b. Such pilot pump 5
6 and the main hydraulic pumps 1 and 2 are driven by a common engine 50.

Front attachment operating devices such as the arm operating device 51, the boom operating device 54, and the bucket operating device 55, and the left traveling hydraulic motor operating device 5
2. The right traveling hydraulic motor operating device 52 has the same configuration as the operating device 18 of the turning hydraulic motor 3, and the pressure oil supply pipelines of these operating devices 18, 51, 54, 55, 52, 53 are provided. 18c, 51c, 54c, 55c, 52c,
The pressure oil taken from the tank 17 is supplied to the 53c by the pilot pump 56. Where this tank 1
Reference numeral 7 corresponds to all the tanks in FIG. 1, and one tank is used in this way, and oil is taken in or discharged by each pump from there.

Pilot lines 18i, 1 of the operating device 18
8h are connected to the pilot operating portions indicated by a and b of the directional control valve 9 for turning as described in FIG. 9, and similarly, the pilot conduits of the arm operating device 51 are respectively connected to the arm The direction switching valves 13a, 13b are connected to the pilot operation portions indicated by c and d, and the pilot pipes of the boom operating device 54 are respectively connected to the boom direction switching valves 12a, 1b.
2b is connected to the pilot operating portions indicated by i and j, and the pilot pipelines of the bucket operating device 55 are connected to the pilot operating portions indicated by k and l of the bucket directional control valve 14, respectively, for the left traveling hydraulic motor. The pilot lines of the operating device 52 are respectively connected to the pilot operating portions indicated by e and f of the left traveling directional switching valve 10, and the pilot lines of the left traveling hydraulic motor operating device 52 are respectively switching the right traveling direction. Valve 1
1 is connected to the pilot operation part indicated by g and h.
With such a configuration, by operating the operation devices 51, 54, 55 for the front attachment, the directional switching valves 13a, 13b, 12 for the front attachment are operated in the same manner as in the operation device 18 for the turning hydraulic motor 3.
a, 12b, 14 will be operated.

A throttle 57 (this may be a throttle valve; the same applies hereinafter) is provided in the pressure oil supply pipe 31a connected to the pilot pump 56, and the outlet side of this throttle 57 is provided. It is connected to the control lines 33 and 34.
This restrictor 57 keeps the pressure on the inlet side constant, whereby each operating device 18, 51, 54, 5 is operated.
5, 52, 53 pressure oil supply lines 18c, 51c, 54
The pressures at c, 55c, 52c and 53c are kept constant.

The other parts are the same as those in the configuration shown in FIG. 1, and therefore the same effects as those of the first embodiment shown in FIG. 1 can be obtained.

FIG. 3 is a circuit diagram showing a third embodiment of the parking brake hydraulic circuit for turning according to the present invention.
Is a tank, 60 is a pilot pump, 60a is a pressure oil supply pipeline, and 61 and 62 are control pipelines. The portions corresponding to those in FIG.

In the figure, the third embodiment differs from the first and second embodiments described above in that the first control line 3
4 is removed from the directional control valve 9 for turning. For this reason, in the second pilot chamber 47 of the opening / closing valve 45, the direction switching valves 14, 12a, 1 for front attachment are provided.
The pressure oil is supplied from the auxiliary hydraulic pump 31 only when any one of 2b, 13a, and 13b is operated. Further, a pilot pump 60 is provided, and a pressure oil supply pipe line 60a connected to the pilot pump 60 is connected to control pipe lines 61 and 62 to form a control circuit 64. This control line 61 is provided with an opening / closing valve 45 via a check valve 42 and a throttle 43.
Is connected to the first pilot chamber 46, and the control line 62 leads to the tank 17m through the direction switching valve 9 for turning.

That is, in the third embodiment, the control circuit 33 for the front attachment and the control circuit 64 for the turning hydraulic motor 3 are provided.

Therefore, when the turning operation device 18 is in the neutral position, the direction switching valve 9 is not operated and is in the neutral position. Therefore, the control line 62 communicates with the tank 17m through the direction switching valve 9. Therefore, no pressure builds up in the control conduit 61, and no pressure oil is supplied to the first pilot chamber 46 of the on-off valve 45.

When the operating device 18 is operated, the directional control valve 9 is operated to change from the neutral position, so that the control line 6
2 is shut off by this directional control valve 9. For this reason, pressure rises in the control pipe 61, passes from the pilot pump 60 through the pressure oil supply pipe 60a and the control pipe 61, and further through the check valve 42 to the first pilot chamber 46 of the on-off valve 45. Oil is supplied. In this way, when the operating device 18 is operated, at this time, if none of the directional control valves 14, 12a, 12b, 13a, 13b of the front attachment is operated, the brake is released after the required brake release time Tc. The cylinder 19 operates and the brake of the turning hydraulic motor 3 is released.

After that, when the operation of the operating device 18 is finished and returned to the neutral position, the directional control valve 9 for turning also returns to the neutral position, so that the control line 62 communicates with the tank 17m.
No pressure builds up in the control line 61. Therefore, the pressure oil in the first pilot chamber 46 of the opening / closing valve 45 passes through the throttle 43 and further through the control lines 61 and 62, and then the tank 17
is discharged to m. At this time, if none of the directional control valves 14, 12a, 12b, 13a, 13b of the front attachment are operated, the operating device 18 is returned to the neutral position by the throttle 43 as in the above-described embodiments. After the passage of time, the pressure oil is discharged from the first pilot chamber 46 of the opening / closing valve 45, so that the opening / closing valve 45 returns from the second position 45b to the first position of the neutral position, and the brake is applied. In the release cylinder 19, the pressure oil in the cylinder chamber 19a is removed to the tank 17k, and the turning hydraulic motor 3 is braked. Therefore, after the required brake delay time Tb has elapsed after the operating device 18 returned to the neutral position, the turning hydraulic motor 3 is braked.

As described above, also in the third embodiment, the same effect as in the previous embodiment can be obtained.

In the third embodiment, the pilot pump 60 is not used, and the shuttle valve 40 is provided between the pilot lines 18h and 18i of the operating device 18 as shown in FIG. A configuration may be adopted in which the supply pipeline 60a is connected.

The third embodiment can also be configured as shown in FIG. FIG. 4 shows this as a fourth embodiment, and parts corresponding to those in FIGS. 2 and 3 are given the same reference numerals. In this FIG.
The pilot pump 56 is the auxiliary hydraulic pump 31 in FIG.
60 and the pilot pump 18b. Also in the fourth embodiment, the same effect as that of the previous embodiment can be obtained.

FIG. 5 is a circuit diagram showing a fifth embodiment of the parking brake hydraulic circuit for turning according to the present invention, in which 70 is a pressure compensation valve, 70a is a throttle, 70b is a variable throttle, and 70c.
Is a spring member, and the portions corresponding to those in FIG.

In this figure, the fifth embodiment uses a pressure compensation valve 70 instead of the throttle 43 in the first embodiment shown in FIG.

With a valve having a constant opening amount, when the viscosity of the oil becomes high, it becomes difficult for the oil to pass through this valve and the flow rate decreases. When the viscosity of the oil becomes low, the oil easily passes through this valve and the flow rate becomes low. To rise. When the temperature changes, the viscosity of oil also changes, so the flow rate of the valve having a constant opening amount changes. In this embodiment, by using the pressure compensating valve 70, the discharge flow rate of the pressure oil discharged from the first pilot chamber 46 of the opening / closing valve 45 is made constant, thereby moving the operating device 18 from the operating position to the neutral position. The time from when the brake is released to when the brake releasing cylinder 19 is activated and the turning hydraulic motor 3 is braked, that is, the required brake delay time Tb is not affected by the temperature. In particular, when a valve having a constant opening amount is used, when the temperature rises and the viscosity of the pressure oil decreases, the flow rate at this valve increases, and therefore, when the operating device 18 is returned from the operating position to the neutral position. From the above, the brake release cylinder 19 operates and the required brake delay time Tb from when the brake is driven to the turning hydraulic motor 3 becomes short, and the brake releasing cylinder 19 operates before the turning hydraulic motor 3 is completely stopped. Although a situation may occur in which the turning hydraulic motor 3 is braked, such a situation can be prevented in the fifth embodiment.

The pressure compensating valve 70 includes a throttle 7 having a fixed opening amount.
0a and a variable diaphragm 70b having a variable opening amount. When the temperature changes and the viscosity of the pressure oil discharged from the first pilot chamber 46 changes, the flow rate of the pressure oil in the throttle 70a changes. As a result, the pressure difference between the pressure on the inlet side and the pressure on the outlet side of the throttle 70a changes. On the other hand, the opening amount of the variable diaphragm 70b changes according to the differential pressure and the spring pressure of the spring member 70c. Therefore, when the viscosity of the pressure oil changes and the flow rate at the throttle 70a increases, the differential pressure at the throttle 70a changes, so that the variable throttle 70b reduces the opening amount so that the flow rate there decreases. ,Also,
When the viscosity of the pressure oil changes and the flow rate at the throttle 70a increases, the opening amount increases at the variable throttle 70b so that the flow rate there increases. In this way, the flow rate of the pressure oil in the pressure compensating valve 70 is kept constant even if the viscosity of the pressure oil changes with temperature.

The other structure and operation are the same as those of the first embodiment shown in FIG. Therefore, in the fifth embodiment, the same effect as that of the first embodiment is obtained, and further, even when the viscosity of the pressure oil changes due to the temperature change, the operating device 18 is returned from the operating position to the neutral position. The required brake delay time Tb from when the brake is driven to the turning hydraulic motor 3 can be made constant, and the brake release cylinder 19 is activated before the turning hydraulic motor 3 is completely stopped to turn the turning hydraulic motor 3. A situation in which the hydraulic motor 3 is braked can be avoided.

Of course, also in the first to fourth embodiments described above, the throttle 43 is considered in consideration of the change in the viscosity of the pressure oil with temperature.
However, when the viscosity is low, the brake release cylinder 19 is activated from the time when the operating device 18 is returned from the operating position to the neutral position and the turning hydraulic motor 3 is operated. The required brake delay time Tb until the brake is applied becomes unnecessarily long. In the fifth embodiment, this is not the case.

FIG. 6 is a circuit diagram showing a sixth embodiment of the turning parking brake hydraulic circuit according to the present invention. The parts corresponding to those in FIGS. 2 and 5 are designated by the same reference numerals and their duplicate description will be omitted. .

In FIG. 6, this sixth embodiment uses the pressure compensating valve 70 shown in FIG. 5 instead of the throttle 43 in the second embodiment shown in FIG.
Therefore, in addition to the same effects as those of the second embodiment,
The same effect as that of the fifth embodiment shown in FIG.

In the embodiment shown in FIGS. 3 and 4, instead of the throttle 43, the pressure compensating valve 7 shown in FIG.
The same effect can be obtained by using 0.

FIG. 7 is a circuit diagram showing a seventh embodiment of the parking brake hydraulic circuit for turning according to the present invention.
Reference numeral 84 is a shuttle valve, 85 is a control line, and 86 is a control circuit. The parts corresponding to those in FIG.

This seventh embodiment is similar to the second embodiment shown in FIG.
In the embodiment, instead of the control circuit 32, the opening / closing valve 45 is controlled by the operating device of the front attachment.

7, in the operating device 18 of the turning hydraulic motor 3, as in the second embodiment shown in FIG. 2, the shuttle valve 40 between the pilot conduits 18h and 18i has a third control conduit. 41, the check valve 42, and the throttle 43 are connected to the first pilot chamber 46 of the on-off valve 45 to form the control circuit 35 for the brake release cylinder 19, that is, the operating device 18 for turning. is doing.

Operation device 51 for front attachment,
54, 55 and operating devices 52, 53 for the left and right traveling hydraulic motors 4, 5 have the same structure as the operating device 18 for the turning hydraulic motor 3.

Therefore, the operating device 1 for the turning hydraulic motor 3
8, pilot lines 18h and 18i for controlling the directional control valve 9 for turning are shown.
A shuttle valve 40 is provided between 8h and 18i,
Similarly, in the arm operating device 51, the shuttle valve 80 is provided between the pilot conduits (indicated by c and d) that control the arm directional control valves 13a and 13b, and in the boom operating device 54. Similarly, the shuttle valve 81 is provided between the pilot conduits (indicated by i and j) that control the directional control valves 12a and 12b for the arms, and the operating device 55 for the bucket also similarly operates for the bucket. A shuttle valve 82 is provided between pilot lines (indicated by k and l) that control the directional control valve 14. And
A shuttle valve 83 is provided between the shuttle valves 81 and 82,
Further, a shuttle valve 84 is provided between the shuttle valve 83 and the shuttle valve 80, and the shuttle valve 84 is connected to the second pilot chamber 47 of the opening / closing valve 45 via the control line 85.
It is connected to the.

In such a construction, the shuttle valves 80-8
4 and the control line 85 are the other side of the brake release cylinder 19, that is, the operating device 5 of the front attachment.
A control circuit 86 composed of 1, 54, 55 is formed, and when all of the operation devices 51, 54, 55 of the front attachment are in the neutral position (that is, not operated), the operation device for turning. When 18 is operated, the brake release cylinder 19 releases the brake of the turning hydraulic motor 3 after a required brake release time Tc by operating in the same manner as in the previous embodiment. This operating device 18
When the operation of is finished and returned to the neutral position, the required brake delay time T
After the passage of b, the brake release cylinder 19 brakes the turning hydraulic motor 3.

Further, when the operation device 18 for turning is in the neutral position (that is, when it is not operated), when any of the operation devices 51, 54, 55 of the front attachment is operated, the shuttle valve is operated. The pressure oil is supplied to the second pilot chamber 47 of the on-off valve 45 via any one of 80 to 84 and the control line 85, and the on-off valve 45 moves to the second position 45.
b. As a result, the pilot pump 5
Pressure oil is supplied from 6 to the cylinder chamber 19a of the brake release cylinder 19 via the pilot line 44, the on-off valve 45 and the pilot line 48. In this way, when any of the operating devices 51, 54, 55 is operated, the brake of the turning hydraulic motor 3 is released after the required brake release time Tc.

After that, when one of the operating devices 51, 54, 55 of the front attachment which has been operated is finished and returned to the neutral position, at this time, another operating device of the front attachment or a device for turning is operated. Operating device 1
If 8 is not operated, the pressure oil in the second pilot chamber 47 of the opening / closing valve 45 is controlled by the control line 85 and the shuttle valve 80-
Exhausted rapidly via any of 84. As a result, the on-off valve 45 returns to the first position (neutral position) 45a, and the pressure oil in the cylinder chamber 19a of the brake release cylinder 19 is discharged to the tank 17k. In this way, when the shortened brake delay time Trb elapses after the operation of the operation device for the front attachment is completed, the turning hydraulic motor 3 is braked by the brake release cylinder 19.

In this way, the control circuit 32 used in the previous embodiment is unnecessary, and the same effect as in the previous embodiment can be obtained.

FIG. 8 is a circuit diagram showing an eighth embodiment of the turning parking brake hydraulic circuit according to the present invention. The parts corresponding to those in FIG. 7 are designated by the same reference numerals and the duplicate description will be omitted.

As shown in FIG. 8, this eighth embodiment is similar to the seventh embodiment shown in FIG. 7, except that the throttle 43 in the third control conduit 41 is replaced by the one shown in FIGS. The pressure compensating valve 70 shown in FIG. 2 is used, and these operations are similar to those described above. Therefore, in the eighth embodiment, the same effect as that of the seventh embodiment shown in FIG. 7 can be obtained, and further, the pressure compensating valve 70 causes the turning operation device 18 to finish operating the turning hydraulic pressure. The effect that the required brake delay time Tb until the brake is applied to the motor 3 is maintained constant regardless of the change in the viscosity of the pressure oil due to the temperature is also obtained.

[0083]

As described above, according to the present invention,
When working on a sloping ground, the parking brake acts immediately after the operation of the front attachment is completed, so that the swivel base does not move unnecessarily and it is safe.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 4 is a configuration diagram showing a fourth embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 5 is a configuration diagram showing a fifth embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 6 is a configuration diagram showing a sixth embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 7 is a configuration diagram showing a seventh embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 8 is a configuration diagram showing an eighth embodiment of a turning parking brake hydraulic circuit according to the present invention.

FIG. 9 is a configuration diagram showing an example of a conventional turning parking brake hydraulic circuit.

[Explanation of symbols]

1 and 2 main hydraulic pump 3 turning hydraulic motor 3a rotating shafts 4 and 5 left and right traveling hydraulic motors 6 to 8 cylinders for front attachment 9 turning direction switching valve 10, 11 left and right traveling hydraulic motors 12a, 12b, 13a , 13b, 14 Directional switching valve for front attachment 17 Tank 18 Operating device 18a Operating lever 18b Pilot pump 18e, 18f Pilot valve 18h, 18i Pilot line 19 Brake release cylinder 19a Cylinder chamber 19b Spring member 19c Brake member 21 Check valve 22 Throttle 31 Auxiliary hydraulic pump 32 Control circuit 33 Control line 34 for second 34 First control line 35 Control circuit 40 Shuttle valve 41 Third control line 42 Check valve 43 Throttle 44 Pilot line 45 Open / close valve 45a First Position 45b second position 45c Member 46 First pilot chamber 47 Second pilot chamber 48 Pilot line 49 Cylinder controller 50 Engine 51 Arm operating device 52 Operating device for left traveling hydraulic motor 4 (left traveling hydraulic motor operating device) 53 Right traveling For operating the hydraulic motor 5 for operation (rightward traveling hydraulic motor operating device) 54 boom operating device 55 bucket operating device 56 pilot pump 57 throttle 60 pilot pump 60a pressure oil supply conduits 61, 62 control conduit 70 pressure compensation valve 80 ~ 84 shuttle valve 85 control line 86 control circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16D 65/20 F15B 11/16 A F term (reference) 2D003 AA01 AB02 BA07 CA02 DA03 3H089 AA21 AA60 AA71 CC01 CC08 CC11 DA02 DA07 DB45 DB48 EE07 EE08 EE13 EE22 EE32 FF05 GG02 JJ02 3J058 AA06 AA30 AA38 BA12 CC03 CC72 CC78 CD03 DB21 FA17

Claims (3)

[Claims] 1. A brake of a turning hydraulic motor is released by operation of at least one of an operating device for a front attachment and an operating device for turning, and when the operating devices are all set to a neutral position, A parking brake hydraulic circuit for turning equipped with a brake release cylinder for applying a brake to a turning hydraulic motor, comprising first and second pilot chambers, and supplying pressure oil to the first and second pilot chambers. Then, by connecting the first pilot line connected to the brake release cylinder to the second pilot line connected to the hydraulic pump and supplying pressure oil to the brake release cylinder, When the brake of the hydraulic motor for use is released and pressure oil is discharged from the first and second pilot chambers, the first pilot pipe connected to the brake release cylinder To a tank and discharge pressure oil from the brake release cylinder to brake the turning hydraulic motor, and a first control pipe that detects at least the state of the directional switching valve for the front attachment. A second passage communicating between the first control conduit and the first pilot chamber of the on-off valve.
And a second control line, wherein the second control line detects that at least one of the directional control valves for the front attachment is in the operating position. Pressure oil is supplied to the first pilot chamber of the on-off valve from the first control line, and the first control line detects that all of the directional control valves for the front attachment are in the neutral position. A first control circuit for discharging the pressure oil in the first pilot chamber to a tank, and a third control line are connected to the second pilot chamber of the opening / closing valve via a check valve and a throttle. When the operating device of the turning hydraulic motor is operated, the pressure oil from the hydraulic pump is supplied to the second pilot chamber of the opening / closing valve via the third control line and the check valve. When the operation of the operating device is completed, A second control circuit for discharging the pressure oil in the second pilot chamber to the tank through the throttle and the third control pipe, and returning all the directional control valves for the front attachment to the neutral position. The time from when the brake release cylinder is activated until the brake is applied to the turning hydraulic motor, the brake release cylinder is actuated after the operation of the operating device of the turning hydraulic motor is finished A parking brake hydraulic circuit for turning, which is configured to be shorter than the time it takes to brake the hydraulic motor. 2. When the brake of the hydraulic motor for turning is released by operating at least one of the operating device for the front attachment and the operating device for turning, and when all these operating devices are set to the neutral position, the turning operation is performed. Is a parking brake hydraulic circuit for turning equipped with a brake release cylinder for applying a brake to a hydraulic motor for use, having first and second pilot chambers, and pressure oil is supplied to the first and second pilot chambers. At this time, the first pilot line connected to the brake release cylinder is connected to the second pilot line connected to the hydraulic pump and pressure oil is supplied to the brake release cylinder, whereby When the brake of the hydraulic motor is released and the pressure oil is discharged from the first and second pilot chambers, the first pilot pipe line connected to the brake release cylinder is opened. Connected to at least the hydraulic circuit of the operating device for the front attachment, and an on-off valve that brakes the turning hydraulic motor by discharging the pressure oil from the brake release cylinder. When at least one of the operation devices for the front attachment is operated, pressure oil is supplied from the hydraulic pump to the first pilot chamber of the opening / closing valve, and when all the operations of the operation device for the front attachment are completed. A first control circuit for discharging the pressure oil in the first pilot chamber of the opening / closing valve to a tank, and a third control line for connecting the second pilot of the opening / closing valve via a check valve and a throttle. When the operating device for the turning hydraulic motor is operated, the pressure oil from the hydraulic pump is supplied to the chamber via the third control line and the check valve. The pressure oil in the second pilot chamber of the opening / closing valve is supplied to the second pilot chamber of the closing valve and the operation of the operating device is completed, and the pressure oil is supplied through the throttle and the third control line. And a second control circuit for discharging the front attachment to the tank, and the time from when all the directional control valves for the front attachment are returned to the neutral position until the brake release cylinder is activated to brake the turning hydraulic motor. Is configured to be shorter than the time from the end of the operation of the operating device for the turning hydraulic motor until the brake releasing cylinder is actuated and the brake is applied to the turning hydraulic motor. Parking brake hydraulic circuit for turning. 3. The turning parking brake hydraulic pressure according to claim 1, wherein, instead of the throttle, a pressure compensating valve that maintains a constant flow rate of pressure oil regardless of temperature change is used. circuit.