JPS62191398A - Winch drive controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a winch drive control device.

[Prior Art] FIG. 1 is a system diagram showing a conventional winch drive control device.

In FIG. 1, the switching valve 6 either 1) communicates the hydraulic source 4 with the hydraulic conduit 6a and the reservoir 5 with the hydraulic conduit 6b, or 2) or communicates the hydraulic source 4 with the hydraulic conduit 6b. In addition, the reservoir 5 is connected to the hydraulic conduit 6a, and 3) or both of the hydraulic conduits 6a and 6b are selectively opened to the reservoir 5.

The switching valve 7 is configured to: 1) set its switching position to 7A when the switching valve 6 is set to communicate the hydraulic power source 4 with the hydraulic pipe line 6a and the reservoir 5 with the hydraulic pipe line 6b; 3) When the switching valve 6 communicates the hydraulic source 4 with the hydraulic line 6b and the reservoir 5 with the hydraulic line 6a, the switching position is set to 70; 6b are both opened to the reservoir 5, the switching position is set to 7B.

A brake 1b is provided on the drive shaft 1a of the hydraulic motor 1,
The brake 1b is interlocked with a hydraulic actuator 2, and the interlocking structure is such that the brake 1b is operated by a piston 2b in the hydraulic actuator 2, and the brake 1b operates on the piston 2b to brake the rotation of the drive shaft 1a. The biasing force of the spring 2C is applied in the direction of application, and the displacement chamber 2a in the hydraulic actuator 2 communicates with the hydraulic conduit 2d via the throttle channel 2e.
The brake 1b and the hydraulic actuator 2 constitute a brake device, and a drum (not shown) for a winch that hoists a heavy object as a load is fixed to the drive shaft 1a.

One pressure oil supply hole in the hydraulic motor 1 is connected to the hydraulic pipe line 1
d. Connected to the hydraulic line 6a via the counterbalance valve 3.

In such a conventional configuration, 1) When both the hydraulic lines 6a and 6b are opened to the reservoir 5, the switching position of the switching valve 7 is set to 7B, so that the hydraulic pressure is Conduits 6a and 6
b both become atmospheric pressure, the hydraulic motor 1 is not driven,
Moreover, the displacement chamber 2a also becomes atmospheric pressure, and as a result, the spring 2c urges the piston 2b downward, and the brake 1b applies a mechanical brake to the drive shaft 1a due to this urging.

2) Furthermore, when the switching valve 6 is operated to set the hydraulic source 4 in communication with the hydraulic line 6a and the reservoir 5 in communication with the hydraulic line 6b, the switching position of the switching valve 7 is set to 7A.
As a result, the pressure oil from the hydraulic source 4 is force-fed to the displacement chamber 2a via the hydraulic line 6a, the hydraulic line 2d, and the throttle channel 2e, and the hydraulic oil is transferred to the hydraulic actuator 2.
In this case, the pressure oil forced into the displacement chamber 2a lifts the piston 2b against the urging force of the spring 2C, and as a result, the brake 1b is released.

Simultaneously with the release of the brake 1b, the pressure oil in the hydraulic line 6a is force-fed to one pressure oil supply hole in the hydraulic motor 1 via the check valve 3a and the hydraulic line 1d.
In addition, the other pressure oil supply hole in the hydraulic motor 1 discharges the oil into the reservoir 5 via the hydraulic pipe IC1, the hydraulic pipe 6b, and the switching valve 6, so that the hydraulic motor l rotates in one direction and removes the heavy load. Roll it up.

3) On the other hand, when the switching valve 6 is operated to connect the hydraulic source 4 to the hydraulic line 6b and the reservoir 5 to the hydraulic line 6a, the switching position of the switching valve 7 is set to 7C. , the hydraulic pressure rises in the hydraulic pipe 1c, the hydraulic pressure acts on the counterbalance valve 3, and the hydraulic pipe 1c acts on the counterbalance valve 3.
The pressure oil at d is transferred to the counterbalance valve 3. Hydraulic pipe line 6a
The oil is discharged into the reservoir 5 via the switching valve 6, and the hydraulic motor 1 is rotated to the other side by the action thereof, and as a result, the heavy load on the drive shaft 1a is lowered.

Thus, the conventional arrangement in FIG. 1 is operative.

[Problems to be Solved by the Invention] However, the above conventional configuration has the following problems.

If you gently operate the switching valve 6 to gently lift a heavy load and try to finely adjust the height of the heavy load, it will be 1! ! This results in a phenomenon in which the heavy load is lowered against the rider's will. Therefore, the driver is required to have great skill in such so-called inching operations.

This conventional phenomenon occurs for the following reasons.

In FIG. 2, the vertical axis p shows the operating pressure in the hydraulic pipe 1d or 6a with respect to the elapsed time t while the switching valve 6 is slowly operated, and the operating pressure generated in the hydraulic pipe 6a is shown. The pressure characteristic is indicated by p6a, and the operating pressure characteristic generated in the hydraulic line 1d is indicated by pld.

Hereinafter, using FIG. 2, the action of the process of gently hoisting a heavy load will be explained.

As shown in FIG. 2, when the switching valve 6 is gently operated from before its neutral position to increase the hydraulic pressure indicated by the characteristic p6a which increases with the passage of time t in the hydraulic line 6a, the hydraulic pressure is increased. Since the pressure oil in the pipe line 6a is fed under pressure to the hydraulic pipe line 1d via the check valve 3a, the characteristic pld
The pressure also increases at the same value as the characteristic p6a.

However, at the same time as this action, the pressure oil in the hydraulic line 6a is transferred to the switching valve 7, which is in the switching position 7A, and the hydraulic line 2d.
and is forcedly fed to the displacement chamber 2a via the throttle channel 2e. Therefore, when the pumped working pressure reaches the value of PO, the hydraulic pressure in the displacement chamber 2a overcomes the urging force of the spring 2C in the displacement chamber 2a, and the hydraulic actuator 2 releases the brake ib.

When the brake lb is released in this manner, the heavy load on the drive shaft 1a enters a position to drive the drive shaft 1a.

This means that the hydraulic motor 1 performs a pumping action driven by a heavy load from the drive shaft 1a side, and the pumping action is performed by sucking hydraulic fluid from the hydraulic pipe 1c side, and The effect is to discharge the hydraulic fluid to the hydraulic pipe 1d side.

However, in this case, the hydraulic pipe line 1d and the hydraulic pipe line 6
Since the check valve 3a is interposed between the check valve 3a, the pressure oil that is about to be discharged to the hydraulic pipe line 1d by the pumping action of the hydraulic motor 1 is blocked by the check valve 3a, and due to its action, The working pressure in the hydraulic pipe 1d becomes higher than the working pressure in the hydraulic pipe 6a, and its value becomes the load pressure of PL from the operating point a to the operating point a, and the hydraulic motor 1 is able to move against the heavy load. Then, the hydraulic brake is applied.

Here, the load pressure PL is a value determined from the well-known relationship of the following equation.

WR=PL@D/2π or PL=2πφW@R/D (1) However,
W is the weight of the heavy load, R is the radius of the drum on the drive shaft 1a to the point where the rope lifting the heavy load is wrapped around the drum, D is the displacement volume of the hydraulic motor l, π is pi.

In this way, when the brake lb is released, the hydraulic line 1d maintains a constant load pressure PL determined by the weight W of the heavy load, whereas the second
As shown in the figure, the working oil pressure in the hydraulic pipe line 6a is carefully increased as shown in characteristic p6a, and in the operation at points 0 or higher where the working oil pressure becomes higher than the load pressure PL,
For the first time, the pressure oil of the hydraulic source 4 is forced to be fed from the hydraulic pipe line 6a side to the hydraulic pipe line ld side, and it is not until this state, that is, the elapsed time t beyond the operating point C, that the hydraulic motor 1 is activated. The heavy load will be hoisted up and scaled.

Between operating point a and operating point C, a hydraulic motor generally has a seal portion for pressure oil in a rotary valve or the like, and a small amount of pressure oil leaks from the seal portion.

Therefore, if the flow of pressure oil in the hydraulic pipe line 1d is blocked by the check valve 3a as described above, the hydraulic motor 1 will be moved by an amount corresponding to the leakage due to the leakage of the pressure oil from the seal portion. , is driven from the drive shaft 1a side, and as a result, the heavy load falls by the amount of the drive.

That is, as shown in FIG.
When attempting to delicately lift the heavy load on the drive shaft 1a by carefully operating the switching valve 6 toward the operating point C, the heavy load will be lifted between the operating point A and the operating point C. This results in an undesirable phenomenon in which the air pressure drops.

SUMMARY OF THE INVENTION An object of the present invention is to provide a winch drive control device that reduces the problem described above.

[Means for solving problems] The present invention has the following configuration.

The hydraulic motor includes: a: Pressurized oil is fed from the hydraulic source to one pressure oil supply hole in the hydraulic motor, and the pressure oil is discharged from the other pressure oil supply hole in the hydraulic motor to the riser. When the pressure oil rotates the drive shaft of the hydraulic motor to one side and lifts up a heavy load, b: from the side of the other pressure oil supply hole to the side of the one pressure oil supply hole When pressure oil flows to the first pressure oil supply hole, the hydraulic motor rotates the drive shaft in the other direction to lower the heavy load, and the hydraulic motor rotates the drive shaft in the other direction to lower the heavy load; A check valve is interposed between the switching valve and the drive shaft of the hydraulic motor, and a brake device is provided on the drive shaft of the hydraulic motor, and the brake device is configured such that: a: when pressurized oil from the hydraulic source is supplied to the brake device; , the pressure oil releases the brake on the drive shaft, and b = when the supplied pressure oil is released to the atmosphere, the release applies the brake on the drive shaft. A second switching valve is provided between the brake device and the first switching valve.
A switching valve is provided, and the first switching valve is configured to: a: When set to the first switching position, pressurized oil from the hydraulic source is fed to the one pressure oil supply hole through the chinic valve. and the other pressure oil supply hole is set to be open to the reservoir, and at the same time, the pressure oil from the hydraulic pressure source can also be force-fed to the brake device via the second switching valve. b: When set to the second switching position, the pressure oil of the hydraulic source is set to be fed to the other pressure oil supply hole, and the pressure oil is transferred to the one pressure oil supply hole. , c: When set to the neutral position, pressure oil is drawn out from the hydraulic source to the reservoir, and at the same time, pressure oil from the hydraulic source is pumped to the brake device. The second switching valve is configured to close the pressure oil supply to the braking device and to release the pressure oil that has been force-fed to the brake device to the atmosphere, and the second switching valve is configured such that the first switching valve When set to the first switching position, the working pressure between the check valve and the one pressure oil supply hole is changed to the working pressure between the first switching valve and the second switching valve. The operation of the second switching valve is based on the subtracted value (dp), and the operation of the second switching valve is as follows: a: When the subtracted value is smaller than a predetermined value, pressurized oil from the hydraulic source is supplied to the brake device; b = When the subtracted value is larger than a predetermined value, the hydraulic pressure supplied to the brake device is released to the atmosphere.

[Operation] When a heavy load is lifted up to a certain height by a hydraulic motor at a normal speed, the first switching valve is set from its neutral position to the first switching position at a normal speed. By doing so, the following effects are obtained.

When the first switching valve is set to the first switching position, the pressure oil of the hydraulic source is forced to be fed to one pressure oil supply hole in the hydraulic motor via the first switching valve and the check valve, and at the same time Since the same hydraulic pressure is also transmitted to the hydraulic pressure pipe between the first switching valve and the second switching valve, the working pressure between the check valve and one of the pressure oil supply holes is changed from the working pressure to the first switching valve. The value c obtained by subtracting the working oil pressure from to the second switching valve
tp becomes zero and becomes a value smaller than the predetermined value.

Therefore, in this state, the second switching valve supplies pressure oil from the hydraulic source to the brake device, so that the brake device is ready to release the brake of the drive shaft.

From this, the pressure oil fed to one pressure oil supply hole is
Rotates the drive shaft in one direction within the hydraulic motor,
Further, the pressure oil is discharged into the reservoir via the other pressure oil supply hole.

As a result, the heavy load is hoisted up by the rotation of the drive shaft in one direction.

When the heavy load is hoisted to a suitable height, the operator returns the switching valve ':JJ1 from its first switching position to the neutral position.

When the first switching valve is set to the neutral position in this way,
The first switching valve closes the supply of pressure oil from the hydraulic source to the hydraulic motor, and sets the pressure oil that was being fed to the brake system under pressure to be released to the atmosphere. At the same time that the rotation of the drive shaft stops and hoisting of the heavy load stops, the braking device applies a brake to the drive shaft, so that the heavy load is secured at its height position.

However, if the height of the heavy load is not accurate and the height of the heavy load is to be adjusted by final fine adjustment, the following operation will be performed.

The driver gradually switches the first switching valve from its neutral position to the first switching position with the heavy load by an operation such as a so-called inching operation, and this switching is similar to the above-mentioned second switching valve. Assuming that the pressure oil is supplied to the hydraulic motor slowly as in the characteristic p6a explained in the figure, the effect thereof will be explained using FIG.

The vertical axis p and the horizontal axis t in FIG. 3 indicate the same operating pressure p and elapsed time t as in FIG. 2, and the characteristic p6a is the operating pressure in the hydraulic pipe between the first switching valve and the check valve. The # property p1d indicates the operating pressure of the hydraulic pipe line from the check valve to one pressure oil supply hole in the hydraulic motor, and the state of 1 = 0 means that the first switching valve is in the neutral position. This shows the point in time at which switching starts from to the first switching position.

Moreover, PO and load pressure PL in FIG.
Same as in the figure.

When the first switching valve is carefully switched from the neutral position to the first switching position as shown in characteristic p6a, the hydraulic pipe between the first switching valve and one of the pressure oil supply holes road,
In the hydraulic pipeline from the first switching valve to the brake device via the second switching valve, O<p<P as shown in FIG. 3 is initially established.

As shown in the characteristics p6a and P1d in , the oil pressure gradually increases.

In this case, at the first point in time (0<p PO), the oil pressure is at a very low value, so
The hydraulic pressure is not enough to release the brake of the brake system.

As a result, in this state, the brake device is still applying mechanical brakes to the drive shaft, and as a result,
The heavy load is supported by its mechanical braking force,
The heavy load is not ready to drive the hydraulic motor.

However, as explained in the explanation of the action in Figure y12, when the value of the characteristic p6a reaches Po, the brake system is released by the hydraulic pressure, and as a result, the heavy load is hydraulically supported by the hydraulic motor. It becomes like this.

Therefore, as explained in equation (1) above,
The oil pressure (p l d) in the hydraulic pipe between the two-way chain valve and one pressure oil supply hole will rapidly rise toward the value of the load pressure PL, but in this case, in the present invention, Unlike the conventional configuration shown in FIG. 1, since the second switching valve is present, the following operation is performed.

Here, the second switching valve is defined as "When the first switching valve is set to the first switching position, the working pressure (p 1 d) between the check valve and one pressure oil supply hole is It operates according to the value (dp) obtained by subtracting the working oil pressure (p6a) from the first switching valve to the second switching valve, and its operation is as follows: a: When the subtracted value is smaller than a predetermined value, the oil pressure The hydraulic pressure is supplied to the brake equipment from a source, and when the subtracted value (b) is greater than a predetermined value, the hydraulic pressure supplied to the brake equipment is released to the atmosphere. As shown in Fig. 3, when the value of the characteristic pld rapidly increases from the operating point a, which is Po, to the value of the load pressure PL, the difference obtained by subtracting the hydraulic pressure of the characteristic p6a from the hydraulic pressure of the characteristic pld. When the pressure ctp reaches point b1, which exceeds the predetermined value K, as described above, (b): When the subtracted value is greater than the predetermined value, the hydraulic pressure supplied to the brake device is released to the atmosphere. J Therefore, at point b1, the brake device applies a mechanical brake to the drive shaft, the hydraulic braking state by the hydraulic motor disappears, and the hydraulic pressure of the characteristic pld is equal to that of the check valve and one pressure. The pressure oil trapped between the oil supply holes gradually leaks from the seal portion of the hydraulic motor.

In this way, the oil pressure that has reached point b1 gradually leaks from the seal part as described above, and as a result, its characteristic pld
When the differential pressure ctp between the hydraulic pressure of and the characteristic p6a reaches point b2, where it becomes smaller than a predetermined value, 1'a: When the subtracted value becomes smaller than a predetermined value,
Since pressure oil from the hydraulic source is supplied to the brake device, the brake device releases the brake on the drive shaft, and the heavy load is again in a state where the hydraulic brake is applied by the hydraulic motor. Therefore, the characteristic p
ld tries to rise suddenly to the load pressure PL. However, in the same way as when moving from operating point a to point b1, the brake device again applies a mechanical brake to the drive shaft, and this repeating cycle is repeated at point b in Figure 3.
2, b3, b4. It continues like b5...

In this process, while maintaining the differential pressure dp=Kt-, the oil pressure of characteristic p6a increases, and the operation exceeding the predetermined value K of characteristic pld causes the load pressure to rise as shown in Figure 3. When the bs point that becomes PL is reached, the predetermined value K
The effect after exceeding bsl and bs2 is that the hydraulic pressure of characteristic P1d cannot become the working hydraulic pressure higher than the load pressure PL due to the above-mentioned equation (1).
The value of L remains unchanged.

Therefore, in the operation after the bs point, the differential pressure dp becomes less than a predetermined value, and after the bs1 point, the brake device remains in a state where it does not apply the brake, and bsl, bs2 to
As shown in C, the load pressure PL is constant.

As mentioned above, the characteristic p6a gradually increases, and eventually when the hydraulic pressure of the characteristic p6a exceeds the operating point C, which exceeds the value of the load pressure PL, the pressure oil pushes the check valve open and one pressure is increased. Since the oil will be pumped to the oil supply hole, from this point on, slowly rotate the hydraulic motor to one side and gently hoist the heavy load, slightly adjusting the height of the heavy load. It will be possible to adjust.

In this case, the hydraulic brake by the hydraulic motor is about to occur within the time period from point b1 to point bs in FIG.

Since the brake device mechanically supports the heavy load, unlike the conventional action shown in Fig. 2, there is no possibility that the heavy load may fall due to pressure oil leakage during the hydraulic brake action of the hydraulic motor. There are almost no phenomena that occur.

In addition, when lowering a heavy hoisted load as described above, by setting the first switching valve to the second switching position,
The first switching valve is set to "b = pressure oil from the hydraulic source is forced to be sent to the other pressure oil supply hole in the hydraulic motor, and the hydraulic pressure is set to send pressure oil from one pressure oil supply hole in the hydraulic motor to the reservoir. At the same time, the pressure oil from the hydraulic source is set to be pumped to the brake device. Therefore, with the brake of the brake device released, rotate the hydraulic motor in the other direction. As a result, the heavy load begins to fall.

[Example] The present invention will be described below with reference to Examples.

FIG. 4 is a system diagram showing a winch drive control device as an embodiment of the present invention.

In FIG. 4, the same reference numerals as in FIG. 1 indicate the same materials. In FIG. 4, the switching valve 7 in FIG. Conduit 1
The operation of the switching valve 8 is as follows.

The vJ switching valve 8 is similar to a normal switching valve, and its switching position 8A or 8B is switched by the movement in the axial direction of the spool valve inside the switching valve 8, and the movement is as follows: (AaXp8c)> ( AaXp8a)+k
(2) When the switching valve 8 is set to the switching position 8A, (AaX
p8c)<(AaXp8a) +k (3) The switching valve 8 is configured to be set to the switching position 8B.

In this case, Aa is the pressure receiving area of one shaft end surface and the other shaft end surface of the Nisbourg valve, p8a: signal oil pressure in the pilot pipe line 8a.

p8c: Signal oil pressure in pilot pipe 8C, K Nispring 8b affiliated forces, It is.

Here, when formulas (2) and (3) are rearranged, formula (2) shows that when p8cmp8a>k/Aa (5), the switching valve 8 is set to switching position 8A, and formula (3) is as follows: When p8cmp8a<k/Aa (6), the switching valve 8 is arranged to be set at the switching position 8B.

In this way, in equations (5) and (6), k/A
If we set a = K, the operation of the switching valve 8 is as follows.

a: When the differential pressure dp obtained by subtracting the signal oil pressure in the pilot line 8b from the signal oil pressure in the pilot line 8c is greater than a predetermined value (ltiK), the switching position is set to 8A; When the differential pressure dP is smaller than a predetermined value, the switching position is set to 8B.
This means that the configuration is as follows.

The switching valve 9 is operated by a signal hydraulic pressure in a pyrotechnical pipe 9a communicating with a hydraulic pipe 9d, or a signal hydraulic pressure in a pilot pipe 9c communicating with a hydraulic pipe 6a. 5 and when hydraulic pressure is generated in the pilot line 9a, change the switching position to 9A.
b: When the pilot line 9a is open to the reservoir 5 and hydraulic pressure is generated in the pilot line 9C, the switching position is set to 9B.
, c: When the signal oil pressures in the pilot pipes 9a and 9c are both zero, the switching position is set to 9B by the biasing force of the spring 9b.

In this case, the pilot pipe 9 in the switching valve 9
Since the signal oil pressure of a or 9c is determined by the switching position of the switching valve 6, the switching position of the switching valve 9 is as follows: a: When the switching valve 6 is set to the switching position 6A, the switching position is determined by the switching position of the switching valve 6. 9B, b = When the switching valve 6 is set to the switching position 6C, the switching position is also set to 9B, c: When the switching valve 6 is set to the switching position 6B, the switching position is set to 9A. Set.

This means that the configuration is as follows.

The operation of the configuration of the embodiment of the present invention described above will be explained below.

When lifting a heavy load to a certain height by the hydraulic motor 1 at a normal speed, the first switching valve 6 is switched from its neutral position δ60 to the first switching position 6A at a normal speed. Set it to obtain the following effect.

When the switching valve 6 is set to the switching position 6A, the pressure oil of the hydraulic source 4 is transferred from the hydraulic pipe 1d to the hydraulic motor l via the switching valve 6, the hydraulic pipe 6a, and the check valve 3a. The pressure oil is fed to the pressure oil supply hole, and is simultaneously fed to the pilot line 8C, and also from the hydraulic line 6a to the pilot line 8a.
The same hydraulic pressure is transmitted to the reservoir 5 , and the hydraulic line IC communicates with the reservoir 5 via the switching valve 6 .

Therefore, in the switching valve 8, the value dp obtained by subtracting the signal oil pressure in the pilot line 8a from the signal oil pressure in the pilot line 8C becomes zero, and that value is smaller than a predetermined value, so the switching The position is set to 8B.

Therefore, the pressure oil from the hydraulic source 4 is transferred from the hydraulic line 6a to the switching valve 8. It is supplied to the displacement chamber 2a through the hydraulic pipe 2d and the throttle channel 2e, and the piston 2b is supplied by the supply to the displacement chamber 2a.
is pushed up against the biasing force of the spring 2C, and the brake 1b becomes ready to release the brake of the drive shaft.

From this, the pressure oil fed to the hydraulic pipe line 1d rotates the drive shaft 1a in the - direction within the hydraulic motor 1, and furthermore, the pressure oil is transferred from the other pressure oil supply hole in the hydraulic motor 1. It is discharged into the reservoir 5 via the hydraulic line lc.

As a result, the heavy load is hoisted up by the rotation of the drive shaft 1a in one direction, and the operator operates the switching valve at the position where the heavy load is hoisted to an appropriate height. 6 from the switching position 6A to the neutral position 6C.

When the switching valve 6 is set to the neutral position 6C in this way,
The switching valve 6 closes the supply of pressure oil from the hydraulic source 4 to the hydraulic motor l and opens the hydraulic lines 6a and 6b to the reservoir 5. Therefore, the switching valve 9 closes the supply of pressure oil from the hydraulic source 4 to the hydraulic motor l, and opens the hydraulic lines 6a and 6b to the reservoir 5. The signal oil pressure at both becomes zero, and the switching valve 9 is moved to the switching position 9B by the biasing force of the spring 9b.
Similarly, in the switching valve 8, the signal oil pressure in both the pilot pipes 8a and 8C becomes zero (the differential pressure dp is small due to a predetermined value), and the switching valve 8 is set to the switching position i8B. .

As a result, the pressure oil that has been force-fed to the displacement chamber 2a is set to be released to the reservoir 5, so that the rotation of the drive shaft 1a in the hydraulic motor 1 is stopped and the heavy load is removed. As soon as the rolling stops,
The biasing force of the spring 2C acts on the piston 2b to apply the brake 1b, and as a result, the heavy load is secured at its height position.

However, if the height of the heavy load is not accurate and the height of the heavy load is to be adjusted by final fine adjustment, the following operation will be performed.

The driver gradually switches the switching valve 6 from the neutral position 6C to the switching position 6A by a so-called inching operation to move the heavy load, and the switching is explained in FIG. 2 above. It is assumed that pressure oil is supplied to the hydraulic motor l slowly as shown in the characteristic p6a, and its operation will be explained using FIG.

The vertical axis p and the horizontal axis t in FIG. 3 indicate the same operating pressure p and elapsed time t as in FIG. The state of 1=0 indicates the point in time when the switching valve 6 starts switching from the neutral position 6C to the switching position 6A.

In addition, Po and load pressure PL in FIG.
Same as in the figure.

In this way, the switching valve 6 is moved from the neutral position 6C to the switching position 6A.
By carefully switching the hydraulic pressure in the hydraulic pipe 6a to the characteristic p6a, the hydraulic pipe from the hydraulic pipe 6a to the hydraulic pipe 1d, and from the hydraulic pipe 6a to the switching valve 8, the hydraulic pressure 3 (0<p<Po) in the hydraulic pipe line leading to the displacement chamber 2a via the pipe line 2d and the throttle flow path 2e.
As shown in the characteristics p6a and pld, the oil pressure gradually rises.

In this case, at the first point in time (0<p<Po), the oil pressure is at a very low value, so
The hydraulic pressure has not reached the point where the brake 1b is released in the displacement chamber 2a.

As a result, in this state, the brake 1b is still applying a mechanical brake to the drive shaft, and as a result,
The heavy load is supported by its mechanical braking force,
The heavy load is not yet ready to drive the hydraulic motor 1.

However, as explained in the explanation of the action in Fig. 2,
When the value of the above characteristic p6a reaches the operating point a where it becomes PO,
The hydraulic pressure causes the piston 2b to move upward and release the brake lb, so that the heavy load is hydraulically supported by the hydraulic motor 1.

Therefore, as explained in equation (1) above,
The hydraulic pressure (pld) in the hydraulic pipe line 1d is equal to the load pressure PL
It will rapidly rise towards the value of , but in this case,
In the present invention, unlike the conventional configuration shown in FIG. 1, since the second switching valve 8 is present, the following operation is performed.

As shown in Fig. 3, when the value of the characteristic pld is about to suddenly change -hFL from the operating point a at which it becomes PO to the value of the load pressure PL, the oil pressure of the characteristic p6a changes from the hydraulic pressure of the characteristic pld. When the reduced differential pressure cip reaches point b1, where it exceeds a predetermined value K, the differential pressure ctp becomes greater than the predetermined value, and the switching valve 8
Set the switching position to 8A.

As a result, the displacement chamber 2a is connected to the throttle flow path 2e and the hydraulic pipe line 2.
d, is opened to the reservoir 5 via the switching valve 8 and the switching valve 9, so at point b1 in FIG. 3, the hydraulic actuator 2 applies the brake to the brake 1b, and the hydraulic braking state by the hydraulic motor 1 is At that time, the hydraulic pressure of the pld is trapped in the hydraulic conduit 1d between the check valve 3a and one pressure oil supply hole in the hydraulic motor 1, and the trapped pressure oil is caused by the seal in the hydraulic motor l. It gradually leaks from the parts.

In this way, the oil pressure that has reached point b1 gradually leaks from the seal part as described above, and as a result, the momentary pld
When the differential pressure dp between the oil pressure of the brake 1b and the characteristic p6a reaches point b2, which is smaller than a predetermined value, the switching valve 8 is set to the switching position 8B again. is released, and the heavy load is again subjected to hydraulic braking by the hydraulic motor 1, and the characteristic p1d is about to rise rapidly toward the load pressure PL.However, in this case, from the operating point a b1
As with the action on the point, the increase in the characteristic pld causes the brake 1b to mechanically brake the drive shaft again, and this repeating cycle is repeated as b2, b3, b4, b5φ and the fist in Fig. 3. It is repeated like this.

In this way, the differential pressure dp between the characteristic pld and the characteristic p6a
In the process of increasing the oil pressure of characteristic p6a while maintaining =K, the operation exceeding the predetermined value K of characteristic p1d reaches point bs, where the load pressure becomes PL, as shown in Figure 3. If the bsl exceeds the predetermined value K,
, bs2, the oil pressure of the characteristic ptct cannot become the working oil pressure higher than the load pressure PL due to the above-mentioned equation (1), and remains at the value of the load pressure PL.

Therefore, in the operation after the bs point, the differential pressure dp becomes less than a predetermined value, and after the bs1 point, the brake l
bsl, bs2 with no brake applied to b.
As shown in ~C, the load pressure PL is a constant characteristic.

As mentioned above, the characteristic p6a gradually increases, and eventually when the hydraulic pressure of the characteristic pea exceeds the operating point C exceeding the value of the load pressure PL, the pressure oil pushes open the check valve 3a and the hydraulic pipe From this point on, the hydraulic motor 1 is slowly rotated to one side to slowly hoist the heavy load, and the height of the heavy load is finely adjusted. be able to adjust.

In this case, if the hydraulic brake state by the hydraulic motor 1 is about to occur during the to time between point b1 and point bs in FIG. 3, the brake 1b will mechanically support the heavy load. Therefore, unlike the conventional operation shown in FIG. 2, a phenomenon such as a drop of a heavy load caused by leakage of pressure oil during the hydraulic brake operation of the hydraulic motor 1 does not occur.

In addition, when lowering a heavy hoisted load as described above, if the switching valve 6 is set to the second switching position 6B,
The heavy load will descend as shown below.

When the switching valve 6 is set to the switching position 6B, the pressure oil in the hydraulic source 4 is force-fed to the hydraulic line 6b, the hydraulic line 9d, the pilot line 9a, and the hydraulic line IC, and the hydraulic oil is transferred to the hydraulic line 6a and the pilot line 9c. is released to the reservoir 5.

Therefore, the switching valve 9 is set to the switching position 9A, so that the pressure oil in the hydraulic line 9d is transferred to the switching valves 9 and 8.
, the hydraulic oil in the hydraulic pipe line 1c is forced to be fed to the displacement chamber 2a via the hydraulic pipe line 2d and the throttle channel 2e. This acts on the counterbalance valve 3, and as a result of that action, the pressure oil in the hydraulic line 1d is
It is discharged into the reservoir 5 via the counterbalance valve 3, hydraulic line 6a and switching valve 6, and as a result, the drive shaft 1a of the hydraulic motor 1 rotates in the other direction due to its action, lowering the heavy load. I'll let it happen.

[Effects of the Invention] As is clear from the above description, the effects of the winch drive control device according to the present invention are as follows.

A switching valve 8 is interposed between the hydraulic conduit 2d and the hydraulic conduit 6a,
By configuring the operation to be activated by the signal hydraulic pressure of the hydraulic pipe 1d and the hydraulic pipe 6a, the weight of the load can be adjusted against the driver's will in the fine adjustment of the hoisting height of the heavy load. This makes it possible to eliminate the conventional phenomenon of objects falling, and facilitates fine-tuning operations during hoisting.

[Brief explanation of drawings]

FIG. 1 shows a conventional winch drive control device 4 in a system diagram, FIG. 2 shows the operating characteristics of the winch drive control device in FIG. 1 during gentle hoisting, and FIG.
The figure shows the operating characteristics during gentle hoisting when the winch drive control device according to the present invention is used, and FIG. 4 shows the winch drive control device according to the present invention in a system diagram. The main codes used in the examples are as follows. 1: Hydraulic motor, la: drive shaft, 1b = brake, 1d: hydraulic pipe, 2: hydraulic actuator,
3: Counter balance valve, 3a: Check valve,
4: Hydraulic source, 5: Reservoir, 6.8 and 9
: switching valve, 6a and 6b: hydraulic pipe line, 8a and 8, c: pilot pipe line. Patent applicant Sanwa Seiki Co., Ltd. Representative Etsushi Nishikai Figure 1

Claims (1)

[Claims] 1. A hydraulic motor has the following features: a: Pressurized oil is fed from a hydraulic source to one pressure oil supply hole in the hydraulic motor, and the pressure oil is fed from the other pressure oil supply hole in the hydraulic motor. When discharging into the reservoir, the pressure oil rotates the drive shaft of the hydraulic motor to one side, and lifts up the heavy load, b: from the other pressure oil supply hole side to the one side. When the pressure oil flows toward the pressure oil supply hole, the hydraulic motor rotates the drive shaft in the other direction to lower the heavy load, and the one pressure oil A check valve is interposed between the supply hole and the first switching valve, a brake device is provided on the drive shaft of the hydraulic motor, and the brake device includes: a. When pressure oil is supplied, the pressure oil releases the brake on the drive shaft, and b: When the supplied pressure oil is released to the atmosphere, the release applies the brake to the drive shaft. In the above configuration, a second switching valve is interposed between the brake device and the first switching valve, and the first switching valve is moved to the first switching position. When set, the pressure oil of the hydraulic source is set to be forced to be fed to the one pressure oil supply hole through the check valve, and the other pressure oil supply hole is set to be opened to the reservoir; At the same time, the pressure oil of the hydraulic power source is set to be able to be fed under pressure to the brake device via the second switching valve, b: When set to the second switching position, the pressure oil of the hydraulic power source is set to the The pressure oil is set to be fed under pressure to the other pressure oil supply hole, and the pressure oil is set to be drawn out from the one pressure oil supply hole to the reservoir, and at the same time, the pressure oil of the hydraulic pressure source is set to be fed to the brake device. C: When set to the neutral position, the supply of pressure oil from the hydraulic pressure source to the hydraulic motor is closed, and the pressure oil that was being force-fed to the brake device is released to the atmosphere. The second switching valve is set to the first switching position, and the second switching valve has the above-mentioned configuration, and the second switching valve is configured such that when the first switching valve is set to the first switching position, the second switching valve has a It operates based on the value (dp) obtained by subtracting the working oil pressure between the first switching valve and the second switching valve from the working oil pressure, and the operation of the second switching valve is as follows: a: The subtracted value When is smaller than a predetermined value, the pressure oil from the hydraulic pressure source is supplied to the brake device, and b: When the subtracted value is larger than the predetermined value, the hydraulic pressure supplied to the brake device is released to the atmosphere. A winch drive control device having the above configuration, which is configured to be opened to