JPH0444650B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a brake circuit device for a hydraulic swing motor in a hydraulic circuit system for construction machinery, and in particular to braking the rotating shaft of a hydraulic swing motor by supplying pressure oil. The present invention relates to a brake circuit device for a swing hydraulic motor in a hydraulic circuit device for a construction machine such as a hydraulic excavator, which has a mechanical brake device equipped with a brake release cylinder for releasing the brake.

(Prior Art) As shown in FIG. 5, a conventional hydraulic circuit device for a hydraulic excavator includes main hydraulic pumps 1 and 2, and a swing hydraulic system driven by the supply of pressure oil from the main hydraulic pumps. Motor 3, left and right travel hydraulic motor 4,
5, and front attachment operating cylinders, that is, boom cylinder 6, arm cylinder 7, bucket cylinder 8, and control the flow rate and flow direction of pressure oil supplied from the main hydraulic pump to these motors and cylinders, respectively. Directional switching valves for these motors and cylinders, namely, directional switching valve 9 for turning, directional switching valves 10 and 11 for left and right travel,
First and second directional valves 12a, 1 for boom
2b, first and second directional control valves 13 for the arm;
a, 13b, and a directional switching valve 14 for the bucket, and the swing hydraulic motor 3 has a rotating shaft 3a thereof.
A mechanical brake device 15 is provided for braking. 16 is a spare directional control valve. The main hydraulic pump 1 has a pressure oil supply pipe 1a that receives its supply pressure oil, and a directional control valve 9, 13a, 12a,
It is connected to the inlet ports 9a of these directional control valves through the center bypass pipe 1b passing through the directional control valves 16 and 10 (inlet ports other than the directional control valve 9 and the connecting pipes thereto are not shown), and the inlet ports 9a of these directional control valves are The outlet port 9b is connected to the return line 1c (directional control valve 9
(Other exit ports and connecting pipes are not shown), center bypass pipe 1b, and return pipe 1c.
are both connected to tank 17. Further, although not shown, the directional control valves 11, 14, 12b, and 13b are also connected to the main hydraulic pump 2 and the tank 17 in a similar manner. A relief valve device 23 is connected between the directional control valve 9 and the swing hydraulic motor 3, and a similar relief valve device (not shown) is connected between the other directional control valves 10-14 and the corresponding motors or cylinders. A relief valve device is provided.

The directional switching valve 9 for turning is operated by an operating device 18, and the operating device 18 is operated by an operating lever 18a.
, a pressure oil supply pipe 18c that receives the supply pressure oil of the pilot pump 18b, and a return pipe 1 to the tank 17.
8d and selectively operated by the operating lever 18a.
8e, 18f, these pilot valves 18
e and 18f are pilot pipes 18g and 1, respectively.
It is connected to the pilot operating portions 9c and 9d of the directional switching valve 9 for turning via 8h.

Although not shown, the directional control valves 10, 11, 12
A and 12b, and 13a and 13b are also provided with similar operating devices, respectively.

The mechanical brake device 15 has a brake release cylinder 19 that releases the brake on the rotating shaft of the swing hydraulic motor by supplying pressure oil, and the brake release cylinder 19 is connected to the pilot pipes 18g, 1
It is connected via a pipe line 19d to an outlet 19c of a shuttle valve 19b provided in a pipe line 19a connecting the 8h, and constitutes a brake circuit device 20. A check valve 21 that allows the flow of pressure oil but blocks the flow of pressure oil in the opposite direction, and a throttle 22 are connected in parallel.

A driving gear 3c is attached to the rotating shaft 3a of the turning hydraulic motor 3 via a reducer 3b in a well-known manner, and an internal gear of a turning base (not shown) meshes with the driving gear 3c. It's on.

In a hydraulic circuit device including such a brake circuit device 20 for the swing hydraulic motor 3, the operating device 18 of the swing direction switching valve 9 is not operated.
When the valve 9 is in the neutral position, the pressure oil from the pump 1 flows downstream of the valve 9 through the pressure oil supply line 1a and the center bypass line 1b, and the downstream directional control valves 13a, 12a, 10 Depending on the operating status of the valve, it is either directly discharged into the tank 17, or it is supplied to the cylinder or motor of the operated valve to drive it, and then discharged into the tank 17 via the return pipe 1c.

Here, if the operating lever 18a of the operating device 18 is operated in the W direction in FIG. 5, the pilot pressure of the pilot pump 18b enters the pilot pipe 18g via the pilot valve 18e.
Furthermore, it enters the cylinder chamber 19a of the brake release cylinder 19 via the pipe 19e, the shuttle valve 19f and its outlet 19c, the pipe 19d, and the check valve 21, and brakes the rotating shaft 3a of the hydraulic motor 3 against the force of the spring 19b. is released, and the hydraulic motor 3 is made rotatable. Further, the pilot pressure guided to the pilot pipe 18g as described above enters the pilot operating portion 9c of the directional control valve 9, thereby moving the directional control valve 9 from the neutral position shown in the figure to the left operating position. Switched. When the directional control valve 9 is switched in this manner, the oil discharged from the hydraulic pump 1 flows from the pressure oil supply pipe 1a and the center bypass pipe 1b into the valve 9 via the inlet port 9a, and is guided to the hydraulic motor 3. The return oil also returns through the directional valve 9 through its outlet port 9b and is returned to the tank 17 via the line 1c, thereby rotating the hydraulic motor 3.

Further, when the operating lever 18a is returned to the neutral position from the above state, the pilot valve 18e communicates with the tank 17, thereby opening the pilot pipe 18.
g communicates with the tank 17, the pilot operating portion 9c of the directional control valve 9 communicates with the tank 17, and the directional control valve 9 is switched to the neutral position. At the same time, the pressure in the conduit 19d decreases, so the pressure in the cylinder chamber 19a of the brake release cylinder 19 also decreases, and the mechanical brake device 15 is moved in the direction of braking the rotating shaft 3a of the hydraulic motor 3. However, since the pressure oil in the cylinder chamber 19a is stopped by the check valve 21, it passes through the throttle 22. That is, it takes time for the pressure in the cylinder chamber 19a to decrease,
During this time, the outlet port 9b of the directional control valve 9 is closed, the hydraulic motor 3 is braked and the hydraulic motor 3 stops, and then the rotating shaft 3a of the hydraulic motor 3 is locked (braked) by the mechanical brake device 15. ) to be done.

(Problems to be Solved by the Invention) As described above, in the conventional brake circuit device for a swing hydraulic motor, when the operating device 18 of the swing hydraulic motor 3 is operated, the rotation shaft 3a of the hydraulic motor 3 is not braked. The hydraulic motor 3 is released and the hydraulic motor 3 can be rotated, but since the operating devices for other hydraulic cylinders and the motor 4-8 (not shown) are not associated with the brake circuit device 20, these operations cannot be performed. Even if the device is operated, the hydraulic motor 3
The braking of the rotating shaft 3a is not released, which may cause the following problems. In other words, for work using hydraulic cylinders, a front attachment,
In other words, there is excavation work where only the boom, arm, and bucket are moved, but in such work, the side of the bucket is pushed by earth and sand during excavation, or when working on a slope, the turning force is applied to the swivel base. In such a case, the braking of the rotating shaft 3a of the swing hydraulic motor 3 is not released, so the swing reaction force is combined with the relief torque of the relief device 23 for the swing hydraulic motor 3 and the mechanical brake device 15. By receiving the braking force of
Excessive load is placed on the device, reducing its lifespan.

Therefore, an object of the present invention is to improve the hydraulic pressure of construction machinery so that an excessive load is not placed on the reducer of the swing hydraulic motor and its lifespan is not shortened during work in which only the front attachment is moved without rotating the swing base. An object of the present invention is to provide a brake circuit device for a turning hydraulic motor in a circuit.

(Means for Solving the Problems) According to the present invention, in order to achieve the above object, a main hydraulic pump, a swing hydraulic motor driven by the supply of pressure oil from the main hydraulic pump, The hydraulic motor for travel and the hydraulic cylinder for front attachment are operated by their respective operating devices to control the flow rate and flow direction of the pressure oil supplied from the main hydraulic pump to these hydraulic motors and hydraulic cylinders. A mechanical brake device is provided with a hydraulic motor and a directional control valve for the hydraulic cylinder, and the swing hydraulic motor is provided with a brake release cylinder that releases the brake on its rotating shaft by supplying pressure oil. A brake circuit device for a swing hydraulic motor in a hydraulic circuit device for construction machinery, which includes an auxiliary hydraulic pump, and a control circuit connected to the auxiliary hydraulic pump, the brake release cylinder, and the tank, and controlling communication between them. However, when all of the operating devices for the directional switching valve are not operated, and when only the operating device for the directional switching valve for left and right travel is operated, the control circuit controls the brake release cylinder to a tank. and when at least one of the operating device for the directional switching valve for turning and the operating device for other directional switching valves other than the directional switching valve for left and right travel is operated, the brake release cylinder is activated. A brake circuit device is provided, characterized in that it is configured to communicate with the auxiliary hydraulic pump.

(Example) Hereinafter, the present invention will be explained based on a preferred embodiment of a brake circuit device for a swing hydraulic motor shown in the drawings.

FIG. 1 shows a first embodiment of the present invention. In the figure, components equivalent to the conventional brake circuit device shown in FIG. 5 described above are designated by the same reference numerals, and the explanation thereof will be omitted here.

In FIG. 1, a brake circuit device for a swing hydraulic motor of the present invention is generally designated by the reference numeral 30,
It has an auxiliary hydraulic pump 31 and a control circuit 32 connected to the auxiliary hydraulic pump 31, the brake release cylinder 19 and the tank 17 and controlling communication therebetween. The control circuit 32 connects a first pipe line 33 that connects the brake release cylinder 19 with a pressure oil supply line 31a that receives pressure oil supplied from the auxiliary hydraulic pump, and connects the pressure oil supply line 31a and the tank 17. a second conduit 34 that
In the illustrated embodiment, the pipe line 33 is directly connected to the cylinder chamber 19a of the brake release cylinder.
Also, this conduit 33 includes a brake release cylinder 1.
Similar to the conventional one, a check valve 21 and a throttle 22 are provided in parallel at a portion near point 9. Second
The pipe line 34 includes a pipe line portion 34a that communicates the pressure oil supply pipe line 31a and the pilot inlet port 14a of the directional control valve 14, and a pipe section 34a that communicates the pressure oil supply pipe line 31a with the pilot inlet port 14a of the directional control valve 14, and the directional control valves 14, 12b,
Pilot outlet ports 14b, 12d, 13d, 9f, 13f, 1 of 13b, 9, 13a, 12a
2f is the directional control valve 12b, 13b, 9, 13a,
12a, 16 pilot inlet ports 12c, 1
3c, 9e, 13e, 12e, 16a, respectively, and pipe portions 34b, 34c, 34d, 3
4e, 34f, 34g, and a pipe section 34h that communicates the pilot outlet port 16b of the directional control valve 16 with the tank 17. directional switching valves 12a, 12b, 13 for
a, 13b, 14, and a spare directional control valve 16 to reach the tank 17. Each of these directional valves 12a, 12b, 13a, 13b provides communication between the respective pilot inlet port and the pilot outlet port when in the neutral position, thus providing communication between said conduit sections of the second conduit. , and is configured to interrupt communication therebetween when moved even slightly from the neutral position, thus interrupting communication between the conduit portions.

In such a brake circuit device 30, none of the directional control valve operating devices including the turning directional control valve 9 operating device 18 is operated;
Therefore, when all the directional control valves are in the neutral position, the pressure oil from the pump 1 is transferred to the pressure oil supply pipe 1a, the center bypass pipe 1b, and the directional control valves 9, 13.
a, 12a, 16, 10 to the tank 17, and the pressure oil from the pump 2 is also discharged through the pressure oil supply pipe 2a, the center bypass pipe 2b, and the directional control valves 11, 14, 12b, 13b. It is discharged to tank 17 through. At the same time, the auxiliary pump 31
In this state, the pressure oil from the directional control valve 9,
Since the pilot inlet port and pilot outlet port of each of 12a-14 and 12a-12a-14 and 16 are in communication, the pressure oil is discharged into the tank 17 through the pressure oil supply line 31a, the second line 34, and these directional control valves. . Therefore, no pressure is built up in the first pipe line 33,
Pressure oil from the auxiliary pump 31 is not supplied to the cylinder chamber 19a of the brake release cylinder 19, and the rotating shaft 3a of the swing hydraulic motor 3 remains braked by the mechanical brake device 15.

Here, if the operating lever 18a of the operating device 18 of the swing hydraulic motor 3 is operated in the W direction, the pilot pressure from the pilot pump 18b will be transferred to the pressure oil supply pipe 18c and the pilot valve 18e.
The signal enters the pilot line 18g through the pilot line 18g, and is transmitted to the pilot operating portion 9c of the directional control valve 9 for turning, thereby switching the valve 19 to the left operating position. At this time, as mentioned above, the directional control valve 9
is configured so that communication between the pilot inlet and outlet ports 9e and 9f is cut off if the valve is moved even slightly from the neutral position. Communication is cut off between the pipe portions 34d and 34e. Therefore, almost simultaneously with the start of the switching operation of the directional switching valve 9, pressure builds up in the first pipe line 33, and the pressure oil from the auxiliary pump 31 flows through the pressure oil supply pipe 31a, the first pipe line 33, It is supplied to the cylinder chamber 19a of the brake release cylinder 19 through the check valve 21, and the braking of the rotating shaft 3a of the swing hydraulic motor 3 by the mechanical brake device 15 is released. Then, as the switching operation of the valve 9 progresses, pressure oil from the pump 1 flows into the valve 9 through the pressure oil supply pipe 1a, the center bypass pipe 1b, and the inlet port 9a, and the braking is released. is supplied to the hydraulic motor 3,
After being rotated, it is returned to the valve 9 and discharged into the tank 17 through the return line 1c from the outlet port 9b.

When the operating lever 18a of the operating device 18 is returned to the neutral position, the pilot operating portion 9 of the directional control valve 9
c is again communicated with the tank 17, and the valve 9 is also returned to the neutral position. Therefore, the pressure oil from the pump 1 is discharged into the tank 17 through the center bypass line 1b, the return oil from the hydraulic motor 3 is blocked by the valve 9, and the hydraulic motor is braked hydraulically. At the same time, the pilot inlet and outlet ports 9e and 9f of the valve 9 are communicated again, and the second conduit 34 is also communicated with the tank 17 by communicating between its conduit portions 34d and 34e, so that the auxiliary pump 31 Pressure oil from the tank 17 is discharged into the tank 17 through the second line 34. As a result, the pressure in the first pipe line 33 decreases, so the pressure in the cylinder chamber 19a of the brake release cylinder 19 also decreases, and the mechanical brake device 15 is moved in the direction of braking the rotating shaft 3a of the hydraulic motor 3. At this time, the pressure oil in the cylinder chamber 19a is stopped by the check valve 21, so it passes through the throttle 22 and flows into the cylinder chamber 19a.
The pressure in 9a gradually decreases, so that after the hydraulic motor 3 is stopped by hydraulic braking, its rotating shaft 3a
is braked and locked by a mechanical brake device 15.

Note that even if the operating lever 18a is operated in the direction opposite to the W direction in order to rotate the swing hydraulic motor 3 in the opposite direction, the rotation direction of the oiling motor will simply be reversed, and basically the above will not occur. The same thing is done with the action.

Next, when at least one of the operating devices (not shown) of the directional control valves 12a-14, 16, for example, the operating lever of the arm operating device, is operated,
In the same manner as in the case of the operating device 18, the pilot pressure acts on the arm directional control valves 13a, 13b so that at least one of them, e.g., valve 13a,
is switched to one of the operating positions. At this time, in the same way as explained for the directional switching valve 9 for turning,
Communication between the second pipe line 34 and the pipe parts 34e and 34f is cut off, pressure builds up in the first pipe line 33, and pressure oil from the auxiliary pump 31 passes through the first pipe line 33 to release the brake. Cylinder chamber 19a of cylinder 19
is supplied to release the brake on the rotary shaft 3a of the swing hydraulic motor 3 by the mechanical brake device 15, and the pressure oil from the pump 1 is supplied to the arm cylinder 7 through the valve 13a. Therefore, even if a turning force is applied to the turning table due to excavation at this time, all the turning force is transmitted to the hydraulic motor 3 via the drive gear 3c, reduction gear 3b, and rotating shaft 3a.
The turning reaction force is received only by the relief torque of the relief valve device 23 generated by forced rotation of the hydraulic motor 3. Therefore, the reducer 3b
will not be overloaded. When the operating lever for the arm is returned to the neutral position, the directional control valve 13a also returns to the neutral position, and the directional control valve 9 for swinging also returns to the neutral position.
Similarly to the above case, the operation of the arm cylinder 7 is stopped, and the rotating shaft 3a of the swing hydraulic motor 3 is braked and locked by the mechanical brake device 15 again.

The operations described above when operating the arm operating device are the same as those for the boom directional control valve 12.
Substantially the same can be said when operating any of the operating devices for the directional control valve 14, the directional control valve 14 for the bucket, and the directional control valve 16 for the bucket. Braking by the mechanical brake device 15 is released. Therefore, when working to move only the front attachment,
Even if a situation arises in which a turning force is applied to the turning base, the turning reaction force will be received only by the relief torque of the relief device 23 for the turning hydraulic motor 3, so there will be no unnecessary load on the reducer. It is possible to extend its lifespan.

When the operating devices (not shown) for the left and right travel hydraulic motors 4 and 5 are operated, the left and right travel direction switching valves 10 and 11 are switched to one of the operating positions, and the pressure oil from the pumps 1 and 2 is switched to one of the operating positions. It is supplied to hydraulic motors 4 and 5 to rotate them. However, at this time, the second conduit 3 of the control circuit 32
4 is not associated with the valves 10 and 11 in any way, the second pipe line 34 remains in communication with the tank 17, and is braked and locked by the mechanical brake device 15 of the rotating shaft 3a of the swing hydraulic motor 3. It remains as it is. Therefore, when the hydraulic excavator is running, the swivel base is firmly fixed in place.
It is safe because the turning base does not rotate due to turning reaction force when the steering wheel is turned.

The effects of this embodiment can be summarized as follows. First, as is already clear, it is possible to perform work by not only driving the swing hydraulic motor 3, but also by driving the boom cylinder 6, arm cylinder 7, and bucket cylinder 8 to move only the front attachment. Since the braking of the mechanical brake device 15 on the swing hydraulic motor is sometimes released, the swing reaction force generated during such work is received only by the relief torque of the relief valve device for the swing hydraulic motor. , reducer 3b
Excessive load is not placed on the product, and its lifespan is extended. This can be done more effectively by supplying pressure oil to the brake release cylinder 19 by utilizing the switching operation of the directional switching valve. On the other hand, if only the hydraulic motors 4 and 5 for left and right travel are driven, the braking of the mechanical brake device of the hydraulic motor for turning is not released, so when the steering wheel is turned while the vehicle is traveling, the turning base may rotate due to the reaction force of the turning. It is safe. In addition, since pressure oil is supplied to the brake release cylinder 19 by using the switching operation of the directional control valve, when the swing hydraulic motor is driven, the mechanical brake is reliably applied before it starts rotating. The brake of the device can be released, and the mechanical brake device will not drag when starting the swing hydraulic motor. Further, since the brake circuit device 30 is hydraulically completely separated from the pilot circuit system of each operating device, sufficient pressure oil can be supplied to each without being affected by oil pressure fluctuations. For example, in a pilot system such as the operating device 18, the pressure of the pilot pump 18b can be quickly transmitted to the pilot operating parts 9c and 9d of the directional control valve 9, thereby improving the responsiveness of valve operation and the response of hydraulic motor and cylinder operations. You can improve your sexuality. Furthermore, since a sufficient amount of pressure oil is supplied to the brake release cylinder 19 from the auxiliary pump 31, the responsiveness of the operation of the mechanical brake device can also be improved, and therefore the operability is greatly improved. Furthermore, by supplying a sufficient amount of pressure oil to the brake release cylinder 19, the cylinder chamber 1
9a can be made smaller, and the mechanical brake device can be made smaller.

FIG. 2 shows a partial modification of the embodiment shown in FIG. 1, in which the same members as those in the embodiment shown in FIG. 1 are given the same reference numerals, and some parts are omitted. This modified brake circuit arrangement is designated generally at 40 and differs from the embodiment of FIG. 1 in the construction of the directional valve. That is, the turning directional control valve 41 in this brake circuit device 40
has intermediate transitional positions between the neutral position and the left and right forward and reverse operation positions, and in these positions, the pressure oil between the main pump 1 and tank 17 and the swing hydraulic motor 3 is Regarding the main ports related to oil supply and drainage, as in the neutral position, there are an inlet port 41a for pressure oil supply, an outlet port 41b for discharge, and an outlet port 41c on the hydraulic motor 3 side.
41d, and the inlet port 41e and outlet port 41f for the center bypass conduit 1b.
and the second conduit 3 of the brake circuit device.
4, i.e. pilot inlet port 4
1g and pilot outlet port 41h are configured to cut off communication between them, as in the operating position. As a result, in the transitional position, the directional control valve 41 cuts off the communication of the second pipe line 34 between the pipe parts 34d and 34e, but does not cause rotation of the swing hydraulic motor 3. . Operating device 18
The pilot conduits 18g and 18h are connected to pilot operating sections 41i and 41j.

In this modification, when the operating lever 18a of the operating device 18 is operated in the W direction shown in FIG. through the target position to the left operating position. Therefore, when the valve 41 passes through the transitional position, communication between the pilot inlet port 41g and the pilot outlet port 41h is cut off, and the pressure oil from the pump 31 passes through the pressure oil supply pipe 31a to the first
It enters the cylinder chamber 19a of the brake release cylinder 19 through the check valve 21, and the braking of the rotating shaft 3a of the motor 3 by the mechanical brake device 15 is released. During this time,
Pressure oil from the main pump 1 is connected to the pipe line 1a, and the directional control valve 4
The fuel is discharged to the tank 17 through the center bypass inlet port 41e, outlet port 41f, and center bypass line 1b, and therefore the motor 3 is not rotated. Next, when the directional control valve 41 reaches the operating position, the flow from the main hydraulic pump 1 is stopped while the communication between the pilot inlet port 41g and the outlet port 41h is cut off, that is, the brake release cylinder 19 is released from braking. The pressure oil is guided to the hydraulic motor 3 through the pipe line 1a, the pipe line 1b, the inlet port 41a of the directional control valve 41, and the inlet/outlet port 41c,
Also, the return oil is supplied to the inlet/outlet port 41 of the directional control valve 41.
d, is returned to the tank 17 via the outlet port 41b and the return line 1c, thereby causing the hydraulic motor 3 to rotate.

Further, when the operating lever 18a is returned from the above state to the neutral position, the directional control valve 41 is switched from the left operating position to the neutral position through the transitional position. In this case, when the directional control valve 41 passes through the transient position, communication between ports 41a and 41c and between ports 41b and 41d is cut off, ports 41e and 41f are communicated, and the pressure from pump 1 is cut off. As the oil is discharged into the tank 17, a hydraulic brake is applied to the hydraulic motor 3 and the hydraulic motor 3 is stopped. Next, when the directional control valve 41 reaches the neutral position, the pilot inlet port 41g and the outlet port 41h communicate with each other, and the second pipe line 34
The pressure oil from the pump 31 is discharged into the tank 17, and the pressure in the first pipe line 33 is also reduced, so that the pressure in the cylinder chamber 19a of the brake release cylinder 19 is also reduced. Go down. At this time, the pressure in the cylinder chamber 19a is stopped by the check valve 21 and passes through the throttle 22, so the pressure in the cylinder chamber 19a gradually decreases.
Therefore, after the motor 3 has completely stopped, the rotary shaft 3a is braked by the mechanical brake device 15.

Even when the operating lever 18a is operated in the direction opposite to the W direction in FIG. 2 in order to rotate the hydraulic motor 3 in the opposite direction, basically the same effect as described above is performed.

Therefore, according to such a modification, by using a special directional control valve having a transient position as the directional control valve 41 for turning, when the operating device 18 for turning is operated, the hydraulic motor 3 The braking of the rotating shaft 3a by the mechanical brake device 15 is more reliably released before the rotation of the rotary shaft 3a starts, and therefore, the dragging motion due to incomplete release of the braking of the mechanical brake device 15 when the hydraulic motor 3 is started is ensured. Therefore, the life of the mechanical brake device 15 can be extended.

In addition, in the transient device, the directional switching valve 41 blocks communication between the main pump 1, the inlet port 41a and the outlet port 41b, and the inlet/outlet ports 41c and 41d, and the inlet port 4 for center bypass
1e and the outlet port 41f, the structure is not limited to this, but any other structure may be used as long as it does not cause rotation of the swing hydraulic motor 3. For example, the inlet port It is also possible to configure so that either one of the port 41a and the inlet/outlet port 41c or the outlet port 41b and the inlet/outlet port 41d communicate with each other.

In addition, in the modification shown in FIG. 2, only the direction switching valve 41 for turning has been described as having a valve structure having the above-mentioned special transitional position, but this is not limited to this. Such a special valve structure may be adopted for all the other directional control valves 9, 12a-14, 16 except for the directional control valves 10, 11, so that the operating device for the front attachment can be operated. Even in such a case, the braking by the mechanical brake device 15 on the rotating shaft 3a of the swing hydraulic motor 3 can be more reliably released before the front attachment starts operating, and an excessive load is not applied to the reducer 3b. can be avoided more effectively.

FIG. 3 shows a second embodiment of the present invention, in which the brake circuit device of the present invention is generally designated by the reference numeral 50, and members equivalent to those of the embodiment shown in FIG. 1 are designated by the same reference numerals. The operating devices for the arm, left travel, right travel, boom, and bucket that are not shown in FIG. ing. The output lines of the pilot valves in these operating devices are connected to the directional control valve 9 as indicated by symbols a-l.
-14 is connected to the corresponding pilot operating section. The brake circuit device 50 includes an auxiliary hydraulic pump 56 that also serves as a pilot pump, and a control circuit 57 that is connected to the auxiliary hydraulic pump 56, the brake release cylinder 19, and the tank 17, and controls communication between them. , this control circuit 57
, a throttle 58 is provided in the downstream portion of the pressure oil supply pipe 56a that receives pressure oil supplied from the auxiliary hydraulic pump 56, and the first and second pipes 33, 34
is connected to the pressure oil supply pipe 56a further downstream of the throttle 58. Further, from the position between the auxiliary pump 56 and the throttle 58 of the pressure oil supply pipe 56a, the pressure oil supply pipes 56b and 56 for the pilot are connected.
c and 56d are branched, and through these pipes, the pilot pressure generated by the throttle 58 in the pressure oil supply pipe 56a between the auxiliary pump 56 and the throttle 58 is used as the hydraulic pressure source, and the constant directional control valve is operated. 9-14,1
It is designed to act on the inlet of the pilot valve of the operating device 18, 51-55 for 5.

The pressure generated by the throttle 58 in the pressure oil supply pipe 56a can be reduced by using a high discharge output as the auxiliary pump 56 and setting the relief pressure high. When the communication with the first pipe line 3 is cut off, the auxiliary pump 31
It is set to be higher than the pressure generated in 3. Further, the brake release cylinder 19 is made compact with a small hydraulic area so that the braking of the mechanical brake device 15 can be released by a small amount of high-pressure oil entering the cylinder chamber 19a. The diameter of the hole is set to be small enough to generate the high pressure in the pressure oil supply pipe 56a, but to allow a sufficient amount of pressure oil to flow to operate the brake release cylinder 19, In addition, the diameter of the hole in the aperture 22 is set smaller than that of the aperture 58.

In such embodiments, the operating devices 18, 51, 5 for pivoting and for the front attachment are provided.
4 and 55, the second pipe line 34 of the control circuit 57 is connected to the tank 17 at the initial point of the switching operation of the directional control valve, as in the embodiment shown in FIG. communication is cut off,
Since pressure is transmitted quickly even if there is a restriction 58, the high pressure in the pressure oil supply pipe 56a is transferred to the first pipe 33.
The same pressure is instantaneously transmitted to the cylinder chamber 19a of the brake release cylinder 19 through the
At the same time, due to the aforementioned setting of the hole diameter of the throttle 58 and the configuration of the brake release cylinder 19, the amount of pressure oil necessary to operate the brake release cylinder 19 is supplied to the cylinder chamber 19a from the pressure oil supply pipe from the auxiliary pump 56. passage 56a, aperture 58, first conduit 33,
and is instantaneously supplied through the check valve 21 to release the braking of the rotating shaft 3a of the swing hydraulic motor 3 by the mechanical brake device 15. Pressure oil from at least one of the main pumps 1, 2 is then supplied to the associated hydraulic motor or cylinder through the operated directional valve to drive it. When the operating device is returned to the neutral position, the second pipe line 34 is communicated with the tank 17 again, and the pressure in the first pipe line 33 is also lowered, so that the pressure oil in the cylinder chamber 19a of the brake release cylinder 19 is reduced. After the oil is gradually discharged through the throttle 22 with a small hole diameter and the operation of the operated hydraulic motor or cylinder is stopped, the rotating shaft 3a of the swing hydraulic motor 3 is braked again by the mechanical brake device 15. Therefore, substantially the same effect as the embodiment shown in FIG. 1 can be obtained.

Furthermore, in this embodiment, when the operating device is operated, the same pressure as the pressure in the pressure oil supply line 56a is always present in the pipes 56b, 56c, and 56d, so that the pilot valve of the operated operating device is Pressure oil at that pressure is supplied from the auxiliary pump 56 and acts on the pilot operating portion of the directional control valve associated therewith. Therefore, this embodiment eliminates the need for the pilot pump 18b dedicated to the operating device, which was necessary in the embodiment of FIG. 1, and has the additional effect of reducing costs.

FIG. 4 shows yet another embodiment of the present invention, in which the brake circuit device of the present invention is generally designated by the reference numeral 60.
The same reference numerals are given to the same members as in the embodiment shown in FIGS. 1 and 3. The brake circuit device 60 has a control circuit 61 in which a first line 62 is connected to the pressure oil supply line 56a between the auxiliary pump 56 and the throttle 58, and the first line 62 is connected to the pressure oil supply line 56a between the auxiliary pump 56 and the throttle 58.
It is connected to the cylinder chamber 19a of No. 9 via an on-off valve 63. The on-off valve 63 is connected to the pressure oil supply pipe 56a.
The on-off valve 63 has a pilot operating section 63a connected to the downstream side of the throttle 58 via a pilot conduit 64, and this on-off valve 63 has a pilot operating section 63a connected to the downstream side of the throttle 58.
When the pilot pressure is not acting on the first pipe line 62, the communication with the cylinder chamber 19a of the brake release cylinder 19 is cut off and the cylinder chamber 19a is closed.
It is configured to take a closed position in which the first pipe line 62 is communicated with the tank 17 via the return pipe 63b, and to take an open position in which the first pipe line 62 is communicated with the cylinder chamber 19a when pilot pressure is applied. In this embodiment, the orifice 58 is set to have a hole diameter that allows normal pilot pressure to build up in the pressure oil supply pipe 56a, and the hole diameter of the orifice 22 and the dimensions of the brake release cylinder 19 are also normal. .

In this embodiment, operating devices 18, 51, 54, 5 for turning and front attachment are used.
If the communication of the second line to the tank 17 is cut off at the beginning of the switching operation of the directional valve by at least one actuation of the directional valve 58, the pressure is reduced to the throttle 58.
Therefore, the pressure in the pressure oil supply pipe 56a is immediately transmitted to the pilot operating portion 63a of the on-off valve 63 through the throttle 58 and the pilot pipe 64, and switches it to the open position. On the other hand, the first pipe line 62 always has the same pressure as the pressure oil supply pipe line 56a. Therefore, the pressure is immediately applied to the cylinder chamber 19a of the brake release cylinder 19.
, pressure oil from the auxiliary pump 56 is supplied to it, and before the hydraulic motor or cylinder is driven, the braking of the rotating shaft 3a of the swing hydraulic motor 3 by the mechanical brake device 15 is released. When the operating device returns to the neutral position, the second line 34 is communicated with the tank 17 again, the pressure in the pilot line 64 decreases, and the on-off valve 63 returns to the closed position.
Therefore, since the cylinder chamber 19a is communicated with the tank 17 via the return pipe 63b, the pressure oil therein is gradually discharged through the throttle 22, and after the driven hydraulic motor or cylinder is stopped, the turning hydraulic pressure is restored. The motor 3 is braked again by the mechanical brake device 15. Further, as in the embodiment shown in FIG. 3, by installing the throttle 58, the pressure oil from the auxiliary pump 56 can be used as a pressure oil source for the operating device, and a dedicated pilot pump can be omitted.

In this embodiment, the first conduit 62 is connected to the pressure oil supply conduit 56a at a location between the pump 56 and the throttle 58, and the brake release cylinder 19
The structure is such that the pressure is led to a point very close to the tank 17, and the pressure built up by cutting off communication to the tank 17 of the second pipe line is led to the pilot operating part 63a of the on-off valve 63, which requires an extremely small flow rate. ,
This has the effect that the responsiveness to the switching operation of the directional control valve is even better than that of the embodiment shown in FIG.

Note that in both the embodiments shown in FIGS. 3 and 4, the same as explained in the embodiment of FIG.
A special construction is used as a directional valve with a transient position shown in FIG. 2, which further ensures that the braking by the mechanical brake device 15 is released prior to activation of the hydraulic motor or cylinder. I can do it.

(Effects of the Invention) As is clear from the above, according to the brake circuit device for a swing hydraulic motor of the present invention, the control circuit for controlling communication between the auxiliary hydraulic pump, the brake release cylinder, and the tank is connected to the directional control valve. When all of the operating devices are not operated, or when only the operating device for the left/right directional switching valve is operated, the brake release cylinder is communicated with the tank,
When at least one of the operating device for the directional switching valve for turning and the operating device for other directional switching valves other than at least the directional switching valve for left and right travel is operated, the brake release cylinder is communicated with the auxiliary hydraulic pump. Because of this structure, even when the swivel table is not swiveled and only the front attachment is moved, pressure oil is supplied to the brake release cylinder, and the braking caused by the mechanical brake device on the rotating shaft of the swivel hydraulic motor is released. Therefore, even if a turning force is applied to the turning table during such work, the turning reaction force will be received only by the relief torque of the relief device for the turning hydraulic motor, and there will be no space between the turning table and the turning hydraulic motor. This prevents an excessive load from being applied to a certain speed reducer, thereby extending its lifespan.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing a preferred embodiment of a brake circuit device for a swing hydraulic motor according to the present invention, and FIG. 2 is a hydraulic circuit diagram showing a preferred embodiment of a brake circuit device for a swing hydraulic motor according to the present invention, and FIG. FIG. 3 is a partial hydraulic circuit diagram showing a modification; FIG. 3 is a hydraulic circuit diagram showing a second embodiment of the brake circuit device of the present invention;
FIG. 4 is a hydraulic circuit diagram showing a third embodiment of the present invention, and FIG. 5 is a hydraulic circuit diagram showing a conventional brake circuit device for a swing hydraulic motor. In the figure, symbols 1, 2...main hydraulic pump, 3...
Hydraulic motor for swing, 3a... Rotating shaft, 4, 5...
Hydraulic motor for left/right travel, 6, 7, 8... Hydraulic cylinder for front attachment, 9, 41... Directional switching valve for turning, 10, 11... Directional switching valve for left/right running, 12a-14... ...Directional switching valve for front attachment, 15... Mechanical brake device, 17... Tank, 18... Operating device for turning, 19... Brake release cylinder, 30,
40, 50, 60... Brake circuit device, 31,
56... Auxiliary hydraulic pump, 31a, 56a... Pressure oil supply pipe, 32, 57, 61... Control circuit, 3
3, 62...first pipe line, 34...second pipe line,
51, 54, 55... Operating device for front attachment, 52, 53... Operating device for left and right travel, 56b, 56c, 56d... Pressure oil supply pipe for pilot, 58... Throttle, 63 ...Opening/closing valve,
64...Pilot conduit.

Claims (1)

[Claims] 1. A main hydraulic pump, and a swing hydraulic motor driven by the supply of pressure oil from the main hydraulic pump;
The left and right travel hydraulic motors and front attachment hydraulic cylinders are operated by their respective operating devices to control the flow rate and flow direction of the pressure oil supplied from the main hydraulic pump to these hydraulic motors and hydraulic cylinders. The turning hydraulic motor is provided with a mechanical brake device having a brake release cylinder that releases the brake on the rotating shaft by supplying pressure oil. A brake circuit device for a swing hydraulic motor in a hydraulic circuit device for construction machinery, which includes: an auxiliary hydraulic pump; and a control circuit connected to the auxiliary hydraulic pump, the brake release cylinder, and the tank, and controlling communication between them. The control circuit controls the brake release cylinder when all of the operating devices for the directional switching valve are not operated and when only the operating device for the directional switching valve for left and right travel is operated. The brake release cylinder is communicated with the tank, and when at least one of the operating device for the directional switching valve for turning and the operating device for other directional switching valves other than the directional switching valve for left and right travel is operated. A brake circuit device characterized in that the brake circuit device is configured to communicate with the auxiliary hydraulic pump. 2. The control circuit connects a first pipe line that connects the brake release cylinder with a pressure oil supply pipe line that receives pressure oil supplied from the auxiliary hydraulic pump, and connects the pressure oil supply pipe line and a tank. and a second pipe line, and the second pipe line connects the directional control valves to the directional control valves other than the directional control valve for turning and at least the directional control valve for left/right travel. 2. The directional control valves are associated in such a manner that they communicate with the tank when all of the directional control valves are in neutral positions, and that communication with the tank is cut off when at least one of these directional control valves is operated. Brake circuit device. 3. The second pipe line reaches the tank through the directional switching valve for turning and at least other directional switching valves other than the directional switching valve for left and right travel, and these directional switching valves , respectively, are configured to maintain communication with the second conduit when in the neutral position, and to cut off the communication when moved from the neutral position. 4. The brake circuit device according to claim 2, wherein the first pipe line is directly connected to the brake release cylinder. 5 The pressure oil supply pipe is provided with a restriction, and the pressure in the pressure oil supply pipe generated by the restriction is transferred to each of the directional control valves on the upstream side of the restriction. A pilot pressure oil supply line for introduction into the operating device is connected, and both the first and second lines are connected to the first-mentioned pressure oil supply line on the downstream side of the throttle. A brake circuit device according to claim 4. 6 The pressure oil supply pipe is provided with a restriction, and the pressure in the pressure oil supply pipe generated by the restriction is transferred to each of the directional control valves on the upstream side of the restriction. A pilot pressure oil supply pipe for introduction into the operating device is connected, and the first pipe is connected to the first-mentioned pressure oil supply pipe on the upstream side of the throttle and the brake The second pipe line is connected to the release cylinder via an on-off valve, and the second pipe line is connected to the first-mentioned pressure oil supply pipe on the downstream side of the restriction, and furthermore, the second pipe line is connected to the pressure oil supply pipe on the downstream side of the restriction. 3. The brake circuit device according to claim 2, further comprising a pilot conduit connecting the on-off valve to a pilot operating portion of the on-off valve. 7 The swing directional control valve has an intermediate transient state between each of the neutral position and the forward/reverse operating position, which cuts off the communication of the second pipe line with the tank but does not cause rotation of the swing hydraulic motor. The brake circuit device according to claim 2, wherein the brake circuit device is configured to have a targeted position. 8 Each of the directional switching valves for traveling, and at least other directional switching valves other than the directional switching valve for left and right running, is connected to the second conduit between the neutral position and the forward/reverse operation position, respectively. 3. The brake circuit arrangement of claim 2, wherein the brake circuit arrangement is configured to have an intermediate transient position which interrupts communication to the tank but does not cause operation of the associated hydraulic motor and hydraulic cylinder.