JPH08282978A - Driving gear for oil hydraulic motor in crane - Google Patents

Abstract

PURPOSE: To prevent occurrence of a trouble in an oil hydraulic motor due to inferior connection in a drain pipe with a joint serving as a medium. CONSTITUTION: A drain pipe 32 of connecting a drain port of an oil hydraulic motor 14 to a tank 12 is made dividable in the halfway, to provide a quick joint 36 in this dividable part. In this quick joint 36, an oil path is interrupted in a disconnection condition and opened only in a connection condition. In the drain pipe 32, a pressure switch 38 is provided between the drain port and the quick joint 36. In this pressure switch 38, only in the case that a drain pipe internal pressure is a fixed value or more, a solenoid switching valve 4 is operated to be switched, to forcedly stop driving the oil hydraulic motor 14 and to perform an alarm to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a hydraulic motor in a crane (mainly a large crane).

[0002]

2. Description of the Related Art Generally, when a large mobile crane is transported (especially by land transportation), the crane is disassembled for each unit. In this case, the crane is used as a winch drive or a swing drive. It is also necessary to disassemble the hydraulic piping for driving the equipped hydraulic motor. Therefore, conventionally, consideration has been made so that each hydraulic pipe can be divided along the way, and a quick joint is provided at this severable portion to easily connect and disconnect. The quick joint is configured to close the oil passage to prevent leakage of hydraulic oil from the inside of the pipe when not connected to each other, and to open the oil passage only when they are connected to each other.

[0003]

When connecting the drain pipe, which is one of the hydraulic pipes, by the quick joint, if the quick joints are normally connected to each other, when the hydraulic motor is driven in this state, The hydraulic oil discharged from the drain port of this hydraulic motor will be satisfactorily released to the tank, but by mistake, the connection of the quick joint remains incomplete (that is, the drain oil passage is blocked). When the drive of the hydraulic motor is started, the drain oil cannot be satisfactorily released from the hydraulic motor, and the drive pressure causes the drain pressure in the motor casing to rise excessively. As a result, the motor casing may burst, or the oil seal such as the output shaft portion may be deformed or fallen off and the operating oil may be blown out.

In view of the above circumstances, the present invention provides a hydraulic motor drive device for a crane, which can prevent troubles in the hydraulic motor due to a defective connection of drain piping through a joint. With the goal.

[0005]

As means for solving the above-mentioned problems, the present invention makes it possible to divide a drain pipe connecting a drain port of a hydraulic motor in a crane and a tank in the middle of the crane, and to prevent disconnection at this separable point. In a hydraulic motor drive device in a crane provided with a joint that closes the oil passage in the connected state and opens the oil passage only in the connected state, the pressure inside the drain pipe between the drain port of the hydraulic motor and the joint is above a certain level. In the event of a failure, a warning means for warning the outside is provided (Claim 1).

As the warning means, a warning executing means for executing a warning in a state of being connected to a drive source, and a case where the pressure in the drain pipe between the drain port of the hydraulic motor and the joint exceeds a certain level A device provided with the above-mentioned warning execution means and a pressure switch for connecting the drive source is preferable (claim 2).

Further, according to the present invention, the drain pipe connecting the drain port of the hydraulic motor in the crane and the tank can be divided in the middle, and the oil passage is closed in the non-connected state at this disconnectable portion so that the oil passage is opened only in the connected state. In a hydraulic motor drive device for a crane equipped with an open joint, forcibly stop the drive of the hydraulic motor when the pressure in the drain pipe between the drain port of the hydraulic motor and the joint exceeds a certain level. A means is provided (Claim 3).

The forced stop means is a forced stop executing means that is switched between an allowable state in which the driving of the hydraulic motor is allowed and a forced stop state in which the hydraulic motor is forcedly stopped, and a drain between the drain port of the hydraulic motor and the joint. A pressure switch for switching the forced stop executing means to the forced stop state when the pressure in the pipe exceeds a certain level is preferable (claim 4).

[0009]

According to the apparatus of the first aspect, the supply of the drive oil pressure to the hydraulic motor is started while the connection of the drain pipe through the joint is incomplete (that is, the drain oil passage is in the disconnected state). If the drain pressure between the drain port of the hydraulic motor and the joint rises above a certain level, an external warning is given at that point, and the occurrence of a drain abnormality is immediately notified to the operator etc. Emergency stop is urged.

Further, in the apparatus according to the third aspect of the present invention, the driving of the hydraulic motor is automatically stopped at the above-mentioned time point, and the excessive increase of the drain pressure can be prevented more reliably.

More specifically, in the apparatus according to the second and fourth aspects, when the drain pressure between the drain port of the hydraulic motor and the joint becomes equal to or higher than a certain level, the pressure switch is actuated to execute the warning. Means is connected to the drive source to issue a warning, or forced stop executing means switches from the permissible state to the forced stop state to forcibly stop the drive of the hydraulic motor.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

FIG. 2 shows a lattice boom crawler crane. This crane includes a lower traveling structure having a crawler 1 and an upper revolving structure 2 rotatably installed on the lower traveling structure. A boom is provided on the upper revolving structure 2 so as to be able to be raised and lowered, and the boom can be disassembled into a lower boom 3A, an intermediate boom 3B, and an upper boom 3C. A front winch 4 and a rear winch 5 are provided below the intermediate boom 3B. The wire 6 pulled out from these is hung on the sheaves 7A and 7B at the top of the boom, and the hook block 8 is suspended by the wire 6. Since this lattice boom crane is large, it is disassembled into a plurality of units during its transportation.

FIG. 1 shows a circuit for driving the winches 4 and 5.

This circuit includes a hydraulic pump 10 and a tank 1.
2 and a hydraulic motor 14 for driving a winch, and a control valve 16 is provided between the hydraulic pump 10 and the hydraulic motor 14.

The control valve 16 is a three-position pilot switching valve in the illustrated example, and in a neutral state where pilot pressure is not supplied to both pilot portions 16a and 16b, the discharge oil of the hydraulic pump 10 is fed to the hydraulic motor 14. When the oil is directly discharged to the tank 12 without being supplied and the hydraulic pressure is supplied to the pilot portion 16a, the discharged oil is supplied to the hydraulic motor 14 through the hydraulic pipe 18A and the return oil is discharged to the tank 12 through the hydraulic pipe 18B. When hydraulic pressure is supplied to the pilot portion 16b,
The discharge oil is supplied to the hydraulic motor 14 through the hydraulic pipe 18B, and the return oil is released to the tank 12 through the hydraulic pipe 18A.

The drain port of the hydraulic motor 14 is connected to the tank 12 via a drain pipe 32.

The pilot pressure is supplied to the control valve 16 from the pilot hydraulic pump 24 via the remote control valve 20. The remote control valve 20 guides the discharged oil of the pilot hydraulic pump 24 to the pilot portion 16a or the pilot portion 16b while appropriately reducing the pressure of the discharged oil of the pilot hydraulic pump 24 in accordance with the operating direction and the operating amount of the operating lever 22 provided in the operator's cab. is there.

In FIG. 1, reference numeral 26 is a main relief valve and 28 is a pilot relief valve.

In this hydraulic circuit, due to the disassembly of the crane, the hydraulic pipes 18A, 18B and 32 can be divided in the middle, and the quick joints 34A, 34B and 36 are respectively provided at the cuttable portions. There is.

These quick joints 34A, 34B, 36
Have the same structure. As a representative thereof, the structure of the quick joint 36 is shown in FIGS.

The quick joint 36 comprises a male joint 50 and a female joint 52 which are connected to each other. Male joint 5
0 and 52 are provided with cylindrical main bodies 51 and 53,
The female joint body 53 is provided with a fitting hole 64 into which the tip of the male joint body 51 can be fitted.

In the female joint main body 53, a plurality of through holes 53b radially passing through the side wall surrounding the fitting hole 64 are arranged side by side in the circumferential direction, and each through hole 53b has a diameter larger than the thickness of the side wall. A large ball 66 is accommodated. A sleeve 68 is arranged radially outside of the balls 66, and the sleeve 68 is movable in the axial direction between a position for pushing the balls 66 inward and a position for retracting from the positions. It is fitted onto the joint body 53 and is normally held at the position shown by the elastic force of the compression spring 70. On the other hand, on the outer peripheral surface of the male joint body 51,
A circumferential groove 51a into which the ball 66 can be fitted is formed.

Therefore, the sleeve 68 is attached to the compression spring 70.
The sleeve 68 is retracted from the position shown in the drawing against the resilience of the male joint main body 51 in this state and then the sleeve 68 is returned to its original position. Both joints 50 and 52 can be connected and fixed by pushing the ball 66 inward to fit the ball 66 into the circumferential groove 51a. Then, in this state, the sleeve 68 is retracted again from the position shown in the drawing to release the pushing of the ball 66, so that the male joint main body 51 can be pulled out from the fitting hole 64.

A valve body support member 54 is provided at the tip of the male joint main body 51 and at the inner portion of the fitting hole 64 of the female joint main body 53. It is supported.

The valve body 56 includes a valve shaft 57 and a valve cylinder 58 arranged radially outside the valve shaft 57.
7 and the tip of the valve cylinder 58 are connected to each other via a valve tip 59. Then, the valve shaft 57 is connected to the valve body support member 5
In the state that the valve body 58 is fitted in the fitting hole provided on the fourth side and the valve cylinder 58 is externally fitted to the valve body supporting member 54, the entire valve body 56 is axially movable in the valve body supporting member 54. It is supported.

The valve tip portion 59 has a frustoconical shape whose diameter decreases toward the front side, and a seal member 60 is provided on the tapered outer peripheral surface 59a of the valve tip portion 59. On the other hand, at the distal end of the male joint main body 51 and the inner portion of the fitting hole 64 of the female joint main body 53, tapered inner peripheral surfaces 51a and 53a matching the tapered outer peripheral surface 59a are provided on the main bodies 51 and 53 side. Each is formed.

A compression spring 62 is provided between the valve tip portion 59 and the valve body support member 54, and the valve body 56 is urged toward the tip side by the elastic force of the compression spring 62. Then, in a state where the joints 50 and 52 are not connected as shown in FIG. 3,
By pressing each valve tip outer peripheral surface 59a against the main body inner peripheral surfaces 51, 53, respectively, the oil passage is closed, while the joints 50, 52 are connected to each other as shown in FIG.
The valve tip portions 59 of No. 6 come into contact with each other from the front and are pushed rearward, so that the oil passages 72 and 74 are secured between the valve tip outer peripheral surface 59a and the main body inner peripheral surfaces 51a and 53b, respectively. It has become.

In the present invention, regardless of the specific structure of the joint, it suffices that the oil passage is shut off in the unconnected state and the oil passage is opened only in the connected state, and it has been conventionally used. Various things can be applied.

The circuit shown in FIG. 1 is characterized by being equipped with a pressure switch 38, a power source 40, and an electromagnetic switching valve 44.

The electromagnetic switching valve (forced stop executing means) 44 is
The pilot hydraulic pump 24 is provided between the pilot hydraulic pump 24 and the remote control valve 20 and is in a state where no current flows through the solenoid 44a (state shown in the drawing).
The discharge oil is directly guided to the remote control valve 20, and when a current flows through the solenoid 44a, the hydraulic pressure supply from the pilot hydraulic pump 24 to the remote control valve 20 is cut off. The pressure switch 38 is provided in the drain pipe 32 at a position between the drain port of the hydraulic motor 14 and the quick joint 36. When the pressure in the drain pipe 32 at this position is less than a certain value, the power switch 40 is provided. While electrically disconnecting the solenoid 44a from the solenoid 44a, when the pressure is equal to or higher than a certain level, the power source 40 and the solenoid 44a are connected to supply a current to the solenoid 44a.

Next, the operation of this device will be described.

The crane shown in FIG. 2 is disassembled into each unit during transportation and reassembled after transportation and before use. At the time of this assembly, in the circuit shown in FIG. 1, the quick joints 34A, 34B, 36 connection work is performed.

Thereafter, while the hydraulic pump 10 is in operation, the operator appropriately operates the operation lever 22 to supply the pilot pressure corresponding to this operation to the pilot portion 16a or 16b, thereby operating the control valve 16. Then, the oil discharged from the hydraulic pump 10 is supplied to the hydraulic motor 14 through the control valve 16 and the hydraulic pipe 18A (or 18B), and the hydraulic motor 14 is driven in a predetermined direction.

Here, when the quick joint 36 is completely connected, since the oil passage is opened in this quick joint 36, the drain oil discharged from the hydraulic motor 14 is satisfactorily released to the tank 12. The pressure is kept almost constant.

However, if the hydraulic motor 14 starts to be driven while the connection of the quick joint 36 is incomplete, the drain oil is not released to the tank 12 because the oil passage of the quick joint 36 is blocked. This quick fitting 3
The drain pressure begins to rise on the upstream side of 6.

Here, in the prior art, the drain pressure rises beyond the allowable range, which may damage the motor housing or the oil seal, but in this embodiment, the pressure reaches a constant value. Pressure switch 3
8 is activated, the power source 40 causes the solenoid 4
4a, the electromagnetic switching valve 44 is switched from the open position to the shut-off position shown in the drawing, so that the pilot portion 16 of the control valve 16 can be operated regardless of the operation of the operation lever 22.
Pilot pressure is no longer supplied to a and 16b, and the control valve 16 returns to the neutral position. Therefore, the drive of the hydraulic motor is forcibly stopped before the drain pressure rises excessively, and damage to the motor housing and the oil seal is prevented.

The second embodiment is shown in FIG. In this embodiment, instead of the electromagnetic switching valve 44 shown in the first embodiment, a warning lamp 42 is provided in the cab, and the drain pipe 32 is provided.
When the internal pressure is equal to or higher than a certain level, the pressure switch 38 is activated to connect the warning lamp 42 and the power source (driving source) 40.

According to this structure, as in the case of the above-described embodiment, due to the imperfect connection of the quick joint 36, the inside of the drain pipe 3
When 2 rises, the pressure switch 38 detects this and connects the warning lamp 42 to the power supply 40 to light it. Therefore, the operator can quickly grasp the drain abnormality by this lighting, and immediately. By returning the operation lever 22 to the neutral position and stopping the motor drive, it is possible to avoid an excessive increase in drain pressure.

However, if the hydraulic drive is forcibly stopped as the pressure rises as in the first embodiment, the drive is stopped more quickly in an emergency, and an excessive increase in drain pressure is more reliably avoided. There are advantages.

The present invention is not limited to the above embodiments, and the following modes can be adopted as examples.

(1) In the first embodiment, the forced stop executing means is not limited to the electromagnetic switching valve 44. For example, a hydraulic pump 10 and a hydraulic motor 1 are provided separately from the control valve 16.
4 and a hydraulic pump 10
Forcibly stops the oil discharge of the main relief valve 2
Even if 6 is configured to have a variable set pressure and the set pressure is sufficiently lowered when the drain pressure is abnormal, the hydraulic motor drive can be forcibly stopped.

(2) In the second embodiment, the warning means is not limited to the above-mentioned warning lamp 42, but a display for displaying an abnormality, a speaker for issuing a voice or an alarm sound, etc. may be installed.

(3) In the present invention, the pressure in the drain pipe is detected by a pressure sensor or the like, and this detection signal is input to the computer. Only when the detected pressure is above a certain level, a control signal for warning or forced stop is sent. The computer may be configured to output. However, according to each of the above-described embodiments, the drive source such as the power source 40, the electromagnetic switching valve 44 that is the forced stop execution means, and the warning lamp 4 that is the warning execution means.
With the simple structure in which the pressure switch 38 is provided between the pressure switch 2 and the pressure switch 2, there is an advantage that the forced stop and the warning can be properly executed.

[0045]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, a joint is provided in the middle of the drain pipe of the hydraulic motor, and when the pressure inside the drain pipe between the joint and the drain port of the hydraulic motor exceeds a certain level, the external device Since it is equipped with a warning means to warn the operator, if the drain pressure abnormally rises due to incomplete coupling of the above joint, it is immediately detected and a warning is given to the operator etc., and the motor drive is stopped. There is an effect that the damage to the motor housing, the oil seal, etc. due to the excessive increase of the drain pressure can be prevented by promoting the above.

Since the apparatus according to claim 3 is provided with a forcible stop means for forcibly stopping the drive of the hydraulic motor when the pressure in the drain pipe exceeds a certain level, the drain pressure is abnormal. By automatically stopping the hydraulic motor drive when the hydraulic pressure rises, it is possible to more quickly prevent the drain pressure from increasing and to more reliably avoid damage to the motor housing, the oil seal, and the like due to the excessive increase in the drain pressure.

Here, in the apparatus according to claims 2 and 4, there is provided a pressure switch for switching operation when the pressure in the drain pipe exceeds a certain level, and the warning execution means is driven by switching the pressure switch. Since it is connected to the power source or the forced stop executing means is switched to the forced stop state, there is an effect that the above warning and forced stop can be properly performed with a simple structure without using a computer or the like.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing a drive device for a hydraulic motor according to a first embodiment of the present invention.

FIG. 2 is a side view of a lattice boom crane including the hydraulic motor and the drive device.

FIG. 3 is a cross-sectional view showing a state in which a quick joint provided in the hydraulic motor drive device is separated.

FIG. 4 is a cross-sectional view showing a state in which a quick joint provided in the drive unit of the hydraulic motor is connected.

FIG. 5 is a hydraulic circuit diagram showing a drive device for a hydraulic motor according to a second embodiment of the present invention.

[Explanation of symbols]

 10 hydraulic pump 12 tank 14 hydraulic motor 16 control valve 18A, 18B hydraulic piping 20 remote control valve 32 drain piping 36 quick fitting 38 pressure switch 40 power supply (driving source) 42 warning lamp (warning execution means) 44 electromagnetic switching valve (forced stop) Execution means)

Claims (4)

[Claims] 1. A joint that allows a drain pipe that connects a drain port of a hydraulic motor in a crane and a tank to be divided midway, and closes the oil passage in the disconnectable state in a non-connected state and opens the oil passage only in the connected state. In a drive device for a hydraulic motor in a crane provided with, a warning means is provided to warn the outside when the pressure in the drain pipe between the drain port and the joint of the hydraulic motor becomes a certain value or more. Drive device for hydraulic motor in a moving crane. 2. The hydraulic motor drive device for a crane according to claim 1, wherein the warning means is a warning execution means for executing a warning while being connected to a drive source, and a drain port and a joint of the hydraulic motor. A drive device for a hydraulic motor in a crane, comprising: a pressure switch that connects the warning execution means and a drive source when the pressure in the drain pipe between the two becomes higher than a certain level. 3. A joint which allows a drain pipe connecting a drain port of a hydraulic motor in a crane and a tank to be divided in the middle, and the oil passage is closed at the disconnectable position in a non-connected state and the oil path is opened only in a connected state. In a hydraulic motor drive device for a crane provided with, a forcible stop means for forcibly stopping the drive of the hydraulic motor when the pressure in the drain pipe between the drain port of the hydraulic motor and the joint exceeds a certain level. A drive device for a hydraulic motor in a crane characterized by the above. 4. The hydraulic motor drive device for a crane according to claim 3, wherein the forced stop means is a forced stop executing means that is switched between an allowable state in which the driving of the hydraulic motor is allowed and a forced stop state in which the hydraulic motor is forcibly stopped. When,
A hydraulic pressure in a crane, comprising: a pressure switch for switching the forced stop executing means to the forced stop state when the pressure in the drain pipe between the drain port of the hydraulic motor and the joint exceeds a certain level. Motor drive device.