JPH0415143B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a brake device for an upper rotating body of a construction/material handling machine, in which the upper rotating body is configured to be able to rotate relative to the lower traveling body. .

BACKGROUND OF THE INVENTION Construction and material handling machines with rotating upper bodies, e.g.
By replacing the front attachment, hydraulic excavators can be used for a wide range of different types of work, such as being used for earth and sand excavation work such as with a backhoe, or being used for cargo handling work such as a clamshell or crane. It has its uses. Its greatest feature is that by fully rotating the upper revolving body, it is possible to move tip tools such as bucket buckets, clam shell buckets, crane hooks, etc. to any position within the rotating work range. ,
Although accurate positioning is easy, different brake operation methods and brake characteristics are required for the revolving body for positioning depending on the type of work. That is, when using the hydraulic excavator as a backhoe shown in Figure 2, operate the swing operation lever to make the desired left and right turns, and return the swing operation lever to the neutral position when the tip tool approaches the predetermined position. Therefore, it is required that a braking force is automatically applied to the hydraulic swing motor by a hydraulic brake to stop the swing hydraulic motor. On the other hand, when used as a crane as shown in Figure 3, or in the case of a clamshell (not shown),
When working by moving the hook block 37 up and down with the winch 35 from the tip of the front attachment via the wire rope 36,
When the revolving body attempts to stop with the same hydraulic braking force as in the case of the backhoe, the crane's hook block 37 or clam shell bucket causes a pendulum movement due to inertia force, causing the hook block 37 or clam shell to move to a predetermined position. In this case, since positioning cannot be performed,
Even when the swing operation lever is set to neutral, no braking torque is generated in the swing hydraulic motor, or only a very small amount of braking torque is generated, and the braking force is adjusted as necessary using a separate means. Equipped with a dynamic brake device that allows for Also,
No matter which type of front attachment is installed, a parking swing brake is required to prevent the upper swing structure from turning due to external force for safety when the machine is not in use.

In order to meet the above requirements, the following methods have been implemented in the past. That is, the hydraulic circuit shown in Fig. 4 is mainly suitable for excavating and loading earth and sand with the backhoe bucket 34 shown in Fig. 2, for example, and the hydraulic circuit shown in Fig. 4 is switched by switching the hydraulic switching valve 3 shown in Fig. When the motor 4 is driven to rotate the upper rotating body and then the hydraulic switching valve 3 is set to the neutral position, the oil passages 24 and 25 are closed, but the upper rotating body forcibly turns the rotating motor 4 due to its inertia. High pressure is generated in the oil passages 24 or 25 when the rotation motor 4 is trying to rotate, and at the same time, hydraulic brake torque is generated in the swing motor 4 due to the lock pressure. A so-called brake valve is provided, which consists of relief valves 9 and 9', and check valves 10 and 10' for replenishment, which are provided for the purpose of preventing the operating circuit from running out of hydraulic oil. The rotational inertia force is absorbed under constant brake torque, gradually decelerating and coming to a stop. In addition, when the machine is parked or when equipped with a parking brake to maintain a certain turning position, a brake disc 6 fixed to the output shaft of the turning motor 4 is provided as shown in the electric/hydraulic circuit diagram in FIG. A spring-loaded hydraulic release type brake cylinder 13' is provided, which is applied after the rotational inertia of the rotating body is completely absorbed by the hydraulic brake torque. An oil passage for hydraulic source pressure oil obtained from the tank 31 or the pilot pump 2 is communicated via the electromagnetic switching valve 12 which is switched according to the opening and closing of the provided switch 15.
Therefore, before operating the hydraulic excavator, first close the switch 15 and connect the power source 16 to the electromagnetic switching valve 12, then the electromagnetic switching valve 12 is switched and the pressure oil of the pilot pump 2 is transferred to the release oil chamber of the brake cylinder 13'. Since the water flows in, no brake torque is generated on the brake disc 6, and the hydraulic excavator can freely swing. Next, when the swing operation is temporarily interrupted, the machine is stopped, etc., when the switch 15 is opened or the drive of the pilot pump 2 is stopped, the release oil chamber of the brake cylinder 13' is transferred to the electromagnetic switching valve 12.
The braking force is applied to the brake disc 6 by the biasing force of the built-in spring because the hydraulic pressure source pressure oil is communicated with the tank 31 through the . In this type of parking brake system, the switch 15 must be operated each time the revolving upper structure needs to be stopped, which may be cumbersome depending on the work, or when the revolving upper structure is rotating. If the switch 15 is opened by mistake, it will not only damage the machine but also be dangerous, so in recent years, a further improved circuit as shown in Fig. 6 has been adopted. There is also. That is, in the figure, when pilot pressure acts on any of the pilot oil chambers by switching the hydraulic switching valve 3 for operating the swing motor, when the pilot pressure oil passes through the shuttle valve 14 and closes the pressure switch 32, The power supply 16 communicates with the electromagnetic switching valve 12 and operates it, so that no pilot pressure acts on the pilot oil chamber of the hydraulic switching valve 3, and the hydraulic switching valve 3 returns to the neutral position and the pressure switch 38 opens. , timer 3
Due to the action of step 9, several seconds later, after the upper revolving structure has completely stopped, the power to the electromagnetic switching valve 12 is cut off, and the brake cylinder 13' (Fig. 5) is turned off.
acts.

On the other hand, during cargo handling work as illustrated in Fig. 3, in the circuits shown in Figs. As a result, the suspended load shakes and normal work cannot be carried out, so as a conventional example to deal with this, the hydraulic circuit and brake device are partially modified as shown in FIG. That is, in the neutral position, the hydraulic switching valve 3' in FIG.
The oil passages 24 and 25 are provided with check valves 10 and 5 for replenishment, respectively.
10', but no relief valve is provided, or even if provided, a relief valve (not shown) set at a very low pressure operates in the neutral state. Therefore, when the upper rotating body is started and the hydraulic switching valve 3' is then set to the neutral position, the swing motor 4 is rotated by the inertial force of the upper rotating body, and the discharged oil is transferred to the oil passages 24, 25. , the neutral position communication path of the hydraulic switching valve 3', or the low pressure relief valve, so that no brake torque is generated in the swing motor 4, or even if it is generated, it is extremely small. On the other hand, since it is necessary to stop the upper swing structure at a predetermined position to prevent the suspended load from shaking greatly, a separate brake disc 6 fixed to the swing motor output shaft and a spring release hydraulically operated type are installed as shown in the figure. A dynamic brake is provided which brakes the brake disc 6 by supplying pressure oil from a master cylinder 18 to the hydraulic oil chamber of the brake cylinder 13 when the brake pedal 17 is depressed as appropriate. . In addition, when applying the parking brake, the brake pedal 17 is depressed by pressing the brake pedal 17 while the brake disc 6 is being braked.
Push in the lock button 19 to hold the position.

Problem to be Solved by the Invention When the front attachment of the illustrated hydraulic excavator is replaced and used for excavation and earthwork work or cargo handling work, the required swing braking performance is different as described above, and therefore the same work is performed. When there are different types of work on site, it is best to bring in multiple hydraulic excavators with swing braking performance suitable for each purpose, or else it will require modification and adjustment each time, but it is not suitable for small work sites. Not only is it not suitable, but it also causes great economic and time loss.

In view of these points, the present invention has made simple changes to the hydraulic circuit of a single hydraulic excavator, and is equipped with a selection operation means that allows the user to freely obtain swing brake performance suitable for earthwork work and cargo handling work. This is an attempt to realize a brake device for a rotating body.

Means for Solving the Problems The means of the present invention taken to realize a brake device having the above-mentioned functions are as follows: (a) Reliefs for regulating a predetermined maximum pressure are provided in each of the inflow and outflow passages of pressure oil for operating the swing motor. valve and
A brake valve consisting of a check valve that relieves and replenishes the insufficient amount of oil is provided, and an internal passage is normally open in the middle of the oil passage that communicates with the oil passage, and is closed when a signal is applied to the receiving part. A first communication valve and a second communication valve whose internal passage is normally closed and which opens when a signal is applied to the receiving part are provided in series, A signal is sent to the receiving part of the first communication valve, and from a shuttle valve that takes out the higher pressure oil of the pilot pressure oil that communicates with the two pilot oil chambers of the hydraulic switching valve for operating the swing motor. Pressure oil signals are guided to the receiving parts of the second communication valves independently, and when the operating means near the driver's seat is operated, the oil passages leading to the receiving parts of the first and second communication valves are switched. , a switching means is provided which switches and connects in the opposite manner to the above.

(c) A brake disk is provided on the output shaft of the swing motor to be braked by a brake cylinder, and the brake cylinder hydraulic oil chamber is equipped with a dynamometer that conducts pressure oil from a master cylinder linked to a brake pedal installed near the driver's seat. A brake system will be installed.

Function When engaging in earthwork work such as backhoe,
When the switch near the driver's seat is left open, pressure oil from the hydraulic source passes through the internal passage of the switching means, regardless of the operating position of the swing motor hydraulic switching valve, and the first communication valve is closed. Since it acts on the receiving part, the internal passage of the communication valve is closed, so regardless of the operating position of the hydraulic switching valve for operating the swing motor, the oil passage that communicates the inflow and outflow passages of the pressure oil for operating the swing motor is closed. Therefore, if the hydraulic switching valve for swing is operated in this state to apply rotational force to the rotating body, and then the hydraulic switching valve is set to the neutral position, the hydraulic motor will be forced by the inertia of the rotating body. As the motor rotates, high pressure is generated in the operating circuit, but due to the action of the relief valve provided in the circuit, the pressure does not exceed a predetermined level, and a braking torque is generated by the hydraulic lock corresponding to the set pressure.

When used as a cargo handling machine, operate the operating means and switch the switching means. Then, the pressure oil from the hydraulic source passes through the internal passage of the switching means and acts on the receiving portion of the second communication valve, opening the internal passage of the communication valve. Further, unless a signal acts on the receiving portion of the first communication valve, the internal passage of the first communication valve is open, so the inflow and outflow passages for the hydraulic motor operating pressure oil communicate with each other. When the swing hydraulic switching valve is operated in this state, pilot pressure is generated in either one of the pilot oil passages leading to the two pilot oil chambers of the hydraulic switching valve, and the pressure oil is transferred to the branch oil passage, the shuttle valve, It acts on the receiving part of the first communication valve via the internal passage of the switching means and closes the internal passage, so that the communication between the inflow and outflow passages of the pressure oil for operating the hydraulic motor disappears, and the hydraulic switching valve for swinging The entire amount of high-pressure oil flows into the swing motor without any hindrance, allowing normal startup and swing operation. Next, when the hydraulic switching valve for operating the swing motor is set to the neutral position, the pilot pressure in the pilot oil chamber of the hydraulic switching valve disappears, and the signal to the receiving section of the first communication valve no longer acts.
The first communication valve is opened, and the two oil passages flowing in and out of the swing motor communicate with each other, and no brake torque is generated in the swing motor due to the hydraulic lock. As described above, in order to apply the necessary brakes while the revolving superstructure is freely turning, it is sufficient to not press the brake pedal near the driver's seat. Also, when the engine that drives the hydraulic source pump is stopped,
The hydraulic pressure from the pump decreases, and at the same time, the pilot pressure oil source that switches the hydraulic switching valve disappears, so the second communication valve is closed regardless of the operating position of the switching means, and the swing motor is operated by the hydraulic lock. Maintain braking condition.

Embodiment FIG. 1 is an electro-hydraulic circuit diagram showing an embodiment of the present invention. In FIG. 1, numeral 1 is a main pump that generates high-pressure oil that serves as a power source for a hydraulic excavator, and numeral 2 is a pilot pump that is driven together with the main pump 1. The oil discharged from the main pump 1 passes through the oil passage 22 and flows into the pilot pressure operated hydraulic switching valve 3, which is connected to the swing operation lever 21.
When pilot pressure is generated from the pilot valve 20 to the pilot oil passage 28 or 29 by operating the pilot valve 20, the left/right position is switched to A or B, and high pressure oil is sent to the swing motor 4 through the oil passage 24 or 25. The swing motor 4 is driven, and the return oil returns to the tank 31 through the oil passage on the opposite side, the A or B position passage of the hydraulic switching valve 3, but when the hydraulic switching valve 3 is in the neutral position C, the oil passes through the oil passage 24, 25 are each closed independently, and the high pressure oil from the main pump 1 passes through the passage in the neutral position C and is sent to the tank 3 via the oil passage 23.
1, or branch off midway and flow into other hydraulic switching valves.

In addition, an oil passage 2 which is an operating circuit of the swing motor 4
A relief valve 9 is located between the communication oil passages 4 and 25.
9' and check valves 10 and 10' are provided to constitute a brake valve that protects the swing motor 4 and ensures reliable operation, which is the same as the swing operation circuit for a conventional hydraulic excavator. In the present invention, another communication passage is provided between the oil passages 24 and 25, and a first communication passage is provided in the middle between which the internal passage is normally open but is closed when a signal acts on the pilot oil chamber. Although the valve 11 and the internal passage are always closed,
A second communication valve 11' which opens when a signal pressure is applied to the pilot oil chamber is provided in series, and furthermore, the oil passage 27 from the pilot pump 2 is normally connected to the pilot oil chamber of the first communication valve 11. Road 3
A second oil passage 30 is connected to the outlet port of the shuttle valve 14 from which pressure oil on the high pressure side is taken out of the branch oil passages of the pilot oil passages 28 and 29 from the pilot valve 20. Communication valve 1
When the switch 15 installed near the driver's seat is closed and the power supply 16 is energized, the oil passage 27 is connected to the pilot oil passage 33.
An electromagnetic switching valve 12 is provided to switch and connect the pilot oil passage 30 to the pilot oil passage 32.
Further, the brake disc 6 fixedly installed on the output shaft of the swing motor 4 is provided with a brake cylinder 13, and braking force is applied by pressure oil from a master cylinder 18 linked to the operation of the brake pedal 17. I'm here. The braking force is also adjusted depending on the magnitude of the pedal force.

Note that 5 is a speed reducer directly connected to the output shaft of the swing motor 4, and 7 is a swing pinion fixed to the end of the output shaft of the speed reducer 5, both of which are generally installed on the upper rotating body (not shown) side. 8 is a swing gear fixedly installed on the lower traveling body (not shown), and 26 is an oil passage for supplying pressure oil from the pilot pump 2 to the pilot valve 20.

The operation of the present invention having the above circuit and configuration will be explained.

First, when the hydraulic excavator is used as a proper earthmoving machine, the switch 15 is left open.
In this case, the electromagnetic switching valve 12 is not excited and maintains the H position, so the pressure oil of the pilot pump 2 passes through the oil passage 27, the H position oil passage of the electromagnetic switching valve 12, and the pilot oil passage 32 to the first communication valve. 11, the communication valve 11 is in the E position,
Close internal passages. In this state, pilot valve 2
When the pilot pressure is generated in the pilot oil passage 28 or 29 communicating with the pilot oil chamber of the hydraulic switching valve 3 by operating the operating lever 21 of 0, the hydraulic switching valve 3 is switched from the C position to the A or B position at the same time. , the pilot pressure in the pilot oil passage 28 or 29, whichever is higher, is taken out by the shuttle valve 14 and passes through the pilot oil passage 30, the H-position passage of the electromagnetic switching valve 12, and the pilot oil passage 33 to the second communication line. It acts on the pilot oil chamber of the valve 11', switches the communicating valve 11' from the F position to the T position, and opens the internal passage, but as mentioned above, since the communicating valve 11 maintains the E position, the hydraulic pressure is switched. Main pump 1 where oil is fed through the A or B position passage of valve 3
The high-pressure oil passes through the oil passage 24 or 25, flows into the swing motor 4, drives the swing motor 4, passes through the reduction gear 5 connected to it, rotates the swing pinion that engages with the swing gear 8, and rotates the swing pinion that engages with the swing gear 8. The upper rotating body rotates due to the reaction force. When the operating lever 21 is placed in the neutral position while the upper revolving structure is turning, the pilot pressure disappears in the pilot oil passages 28 and 29, and the tank 3
1, the pressure in the pilot oil chamber of the second communication valve 11' also decreases, and the second communication valve 11' is switched to the ``F'' position, and the first communication valve 11 is operated by the pilot pump 2. In addition, the hydraulic switching valve 3 is in the neutral position C, so the oil passages 24 and 25 are closed independently, and the swing motor 4 is operated by the relief valves 9 and 9' and the check valve 10. , 10', the swing brake performance is exactly the same as in the swing stop operation of a conventional hydraulic excavator.

Next, when the hydraulic excavator is used for cargo handling work or similar purposes, the switch 15 is closed and a swing operation is performed. Then, the electromagnetic switching valve 12 is energized and switched from the H position to the R position, so the pressure oil of the pilot pump 2 passes through the oil passage 27, the R position passage of the electromagnetic switching valve 12, and the pilot oil passage 33 to the second communication valve. 11' into the pilot oil chamber, and the second
The communication valve 11' is switched from the F position to the T position to open the internal passage.

If you operate the control lever in this state, as above,
The hydraulic switching valve 3 is in the A or B position, and the pilot pressure led to the pilot oil passage 30 acts on the pilot oil chamber of the first communication valve 11 via the pilot oil passage 32 and the pilot oil passage of the electromagnetic switching valve 12. , switching the first communication valve 11 from the D position to the E position,
Since the internal passage is closed, the oil passages 24 and 25 do not communicate with each other and are independent, so the hydraulic switching valve 3
The oil passage 24 or 2 passes through the passage in position A or B.
The high-pressure oil flowing into the upper rotating body 5 is fully supplied to the swing motor 4, and the swing motor 4, that is, the upper rotating body starts up and swings without any trouble. Next, when the operating lever is set to the neutral position while the upper revolving structure is turning, the second communication valve 11' maintains the neutral position, but the first communication valve 11 has its pilot oil chamber connected to the pilot oil passage. 32. As a result of communicating with the tank 31 via the reposition passage of the electromagnetic switching valve 12, the pilot oil passage 30, the shuttle valve 14, the pilot oil passages 28, 29, the pilot valve 20, etc., the position is switched from the E position to the N position. Since the internal passages are opened, oil passages 24 and 2
5 communicate with each other via first and second communication valves 11 and 11'. Therefore, the oil passages 24 and 25 are closed when the hydraulic switching valve 3 is in the C position, but the first and second oil passages are closed.
Since communication is established through the communication valves 11 and 11', the swing motor 4 can be rotated freely by the inertia of the upper swing structure. Furthermore, in order to apply an appropriate braking force to the upper revolving structure to bring it to deceleration or stop during cargo handling work, it is sufficient to apply braking by gradually depressing the brake pedal 17. When it is necessary to maintain the braking force by the lock pressure on the swing motor 4, opening the switch 15 causes the first communication valve 11 to be in the E position, or stopping the pilot pump 2 drives the communication valve 11'. Depending on the position of the oil passage 24,
Since the communication path 25 is closed, the purpose is automatically achieved.

Note that the electromagnetic switching valve 12 in the figure does not necessarily have to be an electromagnetic type, and may be a manual type, for example.
Pilot pressure oil is used as the signal medium for switching the first and second communication valves 11, 11', but it can also be easily replaced with electricity or other medium.

Effects of the Invention In this invention, the swing braking performance of a machine equipped with an upper revolving structure, such as a hydraulic excavator, can be easily controlled from the driver's seat using an automatic braking system using a hydraulic lock and arbitrary braking force applied at any time. In addition to allowing you to select which of the dynamic brake methods to use, regardless of the selection status of the two brake methods mentioned above, when the pilot pump drive is stopped, the hydraulic lock is automatically activated. Since the braking force is provided by the brake system, even in a multi-work site where various front attachments, tip tools, etc. are replaced, only one body such as a hydraulic excavator equipped with the brake device of the present invention is sufficient. So it is economical. What's more, even if you forget to switch to automatic braking when parking, you can safely switch to automatic braking as long as you stop the engine that drives the main pump, pilot pump, etc.

[Brief explanation of drawings]

Fig. 1 is an electric/hydraulic circuit diagram showing the brake device of the present invention, Fig. 2 is a side view of a hydraulic excavator with a bucket belt attached to the front attachment, and Fig. 3 is a diagram of a hydraulic excavator equipped with a crane. A side view, Fig. 4 is an example of a hydraulic circuit diagram for swing operation in a conventional hydraulic excavator, and Fig. 5 is an implementation of an electric/hydraulic circuit diagram in which a swing parking brake is added to the hydraulic circuit for swing operation of a conventional hydraulic excavator. Example, 6th
This figure is an electric/hydraulic circuit diagram showing an improved modification of the embodiment shown in FIG. 5, and FIG. 7 is a hydraulic circuit diagram for swing operation mainly used for cargo handling work. 6... Brake disk, 11... First communication valve, 11'... Second communication valve, 12... Solenoid switching valve, 13... Brake cylinder, 17... Brake pedal, 18... Master cylinder.

Claims (1)

[Claims] 1. A hydraulic lock type brake valve consisting of a relief valve that regulates the pressure in the oil path to a predetermined value and a check valve that replenishes the insufficient amount of oil is installed in each of the inflow and outflow passages for pressurized oil for operating the swing motor. In a brake system for a rotating structure, an internal passage is located between the oil passage communicating with the oil inflow and outflow passages and the oil passage, and is normally open, but when a signal acts on the receiving part, the internal passage is closed. The first communication valve and the second communication valve have internal passages that are normally closed but open when a signal is applied to the receiver.
Which of the pilot pressure oil normally communicates with the communication valve of the first communication valve and the two pilot oil chambers of the hydraulic pressure switching valve for operating the swing motor, which receives the pressure oil signal from the hydraulic pressure source to the receiving part of the first communication valve. The pressure oil from the shuttle valve, which extracts high pressure, is communicated independently to the receiving part of the second communication valve, but when the operating means near the driver's seat is operated, the pressure oil is switched, and the pressure oil is communicated with the receiving part of the second communication valve. Apply pressure oil from the above shuttle valve to the receiving part of the valve.
Further, a switching means for transmitting a pressure oil signal from the hydraulic pressure source to the receiving part of the second communication valve, and a brake disk on the output shaft of the swing motor by a brake cylinder operated by a master cylinder interlocked with the brake pedal. A brake device for a rotating body, comprising: a dynamic brake device for braking; and a dynamic brake device for braking.