JPH025680B2 - - Google Patents

Description

Claim 1: A spring-engaged hydraulic release type brake 14 comprising a piston 202 slidably fitted into a brake cylinder 206 and a spring 204 pressing the piston 202, and a high-speed winch transmission 10; A control device for a winch comprising a low-speed transmission 12 and a control valve 28 consisting of a speed control spool 120 and a brake control spool 122 with grooves 160, 162, 164 of different axial length and cross-section, Brake 14 and control valve 28 outlet port 1
52, the brake accumulator 174 has a pressure oil inlet 176 communicating with the control valve 28 and the brake 1.
a housing 178 having a pressure oil outlet 200 communicating with the pressure oil inlet 176; a plurality of passages 186 slidably fitting into a bore 180 in the housing 178 and communicating with the pressure oil inlet 176; and a metering orifice 21 at one end.
4 and pressed by a pair of springs 188, 190; a chamber 194 communicating with the bore 180 at one end thereof and slidably fitting the piston within the housing 178; A metering orifice 214 of the piston 182 and a pressure oil outlet 200 are located within the housing 178.
A chamber 198 is provided between the winch and the chamber 194 and communicates with the chamber 194 through a check valve 196, and when the load of the winch suddenly drops and stops, the high pressure fluid in the chamber 198 and the cylinder 206 is The springs 188 and 190 are fully compressed to communicate the high pressure fluid from the pressure oil inlet 176 to the tank 22, and the reaction force of the springs 188 and 190 causes the fluid in the cylinder 206 to flow into the orifice 214.
cylinder 2 until it no longer communicates with tank 22.
The brake 14 applies back pressure to the hydraulic pressure in the cylinder 206 to cause it to slip, and when the load on the winch slowly drops and stops, the springs 188 and 190 gently press the piston 182 to release the low-pressure fluid in the cylinder 206. A brake force control device for a winch, characterized in that the orifice 214 communicates with the tank 22 and the brake 14 is gradually applied until the communication disappears.

TECHNICAL FIELD The present invention relates to a control device for a hydraulic winch, and more particularly to a brake force control device for a winch such as a pipe layer having a hydraulic boom or hook.

BACKGROUND ART Related prior art includes U.S. Pat. Winches have a variety of uses, and drive and control devices suitable for each use are used. Some of these operate the drum of the winch with a hydraulic motor, with a hydraulic release brake that brakes the drum as the hoisted load descends, and a multi-stage transmission that controls the hydraulic motor to rotate the drum. It also has a device that controls the hydraulic pressure for releasing the brake and adjusts the rate of descent of the load.

There are generally two ways to lower a load, including the US patents mentioned above.

One is "sudden descent," in which the brake force is fully released to allow the load to descend at maximum speed, and after the load has descended to a predetermined point, the brakes are applied again to stop the load. This is a "slow descent" in which the brakes are partially released and the load is lowered at a speed less than its maximum descent speed.

In the case of a ``sudden descent'', the brakes are not applied smoothly when first applied, but are applied suddenly, causing a large impact on related parts, causing premature wear and damage, and shortening the service life.

Therefore, in the case of a "sudden descent" maneuver, it is extremely desirable to apply the brakes gently to soften the impact.

In the case of "slow descent", the load moves further after the operator applies the brake, making it difficult to finely control the stop position of the load, which is undesirable. Furthermore, since the change in braking torque is not large enough to cause the harmful impact described above, there is no need to lower it as described above.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a winch control device which overcomes the above-mentioned drawbacks, softens the large impact when descending rapidly, and allows fine control of the stopping position even when descending slowly.

DISCLOSURE OF THE INVENTION The present invention provides a spring-engaged hydraulic release type brake;
A brake force control device for a winch having a control valve consisting of a high-speed transmission for a winch, a low-speed transmission, a speed control spool, and a brake control spool, including a brake accumulator between the control valve and the brake. By doing this, when the winch descends suddenly, the high pressure fluid in the brake cylinder is communicated with the tank and back pressure is applied to the hydraulic pressure in the cylinder to cause the brake to slip until the fluid communication stops, and when the winch is descending slowly, the high pressure fluid in the cylinder is communicated with the tank. This is a winch brake force control device that communicates low-pressure fluid to a tank and gradually applies the brake until the communication stops.

[Brief explanation of drawings]

FIG. 1 schematically shows the control device and manual actuator of the present invention, FIG. 2 shows a detailed sectional view of the control valve, FIG. 3 shows a sectional view taken along the line - in FIG. 2, and FIG. 3A and 3B show cross-sectional views of brake accumulators, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1 to 4 show an embodiment in which the present invention is applied to a brake force control device for a winch.

In FIG. 1, reference numeral 10 indicates a high-speed transmission, and 12 indicates a low-speed transmission. Pressure oil is sent to each transmission via a control valve 28 to operate the winch at high and low speeds.

Reference numeral 14 is a brake of conventional construction that is spring actuated and hydraulically released.

Reference numeral 16 designates a metering pump which is suitably coupled to a winch drum (not shown) via a clutch (not shown) and rotates at a speed proportional to the rotation of the drum. The metering pump acts as a governor to limit the rotational speed of the drum.

Reference numeral 18 designates a hydraulic control device other than a winch, such as a steering clutch, a power transmission, a service brake for a vehicle, etc. when the device of the invention is used in an earth-moving machine such as a pipe layer.

Reference numeral 20 designates an engine-driven hydraulic pump that sends pressurized fluid from a tank 22 via a connection point 24 to a control valve 28 (described later) and a priority valve (described next).

Code 26 is a priority valve.
Then, pressure oil is sent to the control device of the present invention at a predetermined minimum pressure or a pressure higher than that, and also to the hydraulic device 18 described above. Since the hydraulic device 18 may become insufficiently operated due to a drop in pressure, the priority valve 2 is
6 prevents pressure drops from occurring.

A check valve assembly 54 is located in a line branching from the connection point 24 through a conduit 52 to the control valve 28, and includes a pair of opposing check valves, 56,
60 and the connection point 5 located between these check valves.
8. Check valve 60 is connected to metering pump 16 and prevents backflow of pressure oil from control valve 28 and accumulator 62.

Next, manual actuator 30 and control valve 28
will be explained in detail.

First, the manual actuator 30 is used by an operator to control the control valve 28, and is provided in the operator's cab and includes a handle 32. The handle 32 moves along a slot 34 provided in a console within the driver's cab. Slot 34 forms a shift pattern for handle 32.

A first link 36 connects the handle 32 and the control valve 28 and transmits specific speed control to the transmissions 10,12.

A second link 38 connects the handle 32 and the control valve 28 to control the degree of release of the brake 14.

The third link 40 controls the output and rotation of the winch drive motor and extends to a control device (not shown). The links 36, 38, 40 mentioned above may be control cables or conventional links, for example.

The link 36 effectively acts on the control valve 28 only with respect to the movement of the handle 32 in the left and right direction as seen in FIG. 1, and does not act in any other direction. Link 3
Reference numerals 8 and 40 are effective only for vertical movement of the handle 32, and do not act in other directions.

Slot 34 has a horizontal slot 42, and when handle 32 is at the left end of slot 42, control valve 28 directs transmission 10 to high speed operation. When it is at the right end of the slot 42, it instructs the transmission 12 to operate at low speed.

At both ends of the slot 42, there are further slots 44,
46, and when the handle 32 is pushed down along either of these, a link 40 instructs the winch drive motor to rotate the drum and hoist the load. and slots 44, 46
The speed of the winch drive motor is controlled by the degree to which the inner handle 32 is pushed down.

Furthermore, the slot 42 extends upwardly.
It has 8. When handle 32 engages slot 48, the transmission is in a neutral position. As the brake 14 moves upward in the slot 48, the brake 14 is gradually released, and the degree of release increases as the brake moves upward. At this time, the weight of the load absorbs the friction inside the control device at a certain speed, and after the bump is eliminated, the link 40 is operated to lower the load.

Next, approximately in the middle of slot 42 is a small downwardly extending slot 50 which commands the winch drive motor to rotate as handle 32 moves downwardly within slot 50.

The transmission remains neutral when the handle 32 is located in or between slots 48, 50. Therefore, by using the slot 50, it is possible to drive the winch motor and warm up the components without changing the position of the load. This is an excellent feature when the vehicle is used in cold regions.

Next, the control valve 28 will be explained with reference to FIGS. 2 and 3.

Control valve 28 includes a housing 100 consisting of a center housing 102, a right end housing 104, and a left end housing 106. Left end housing 1
06 is the cable end 1 of each link 36, 38
Accommodates 08,110. central housing 102
has a transmission control bore 112 and a brake control bore 114. housing 10
4 has a cavity 116 concentric with the bores 112, 114, respectively, which accommodates a spring centering assembly 118, which assemblies 118 are fitted into the bores 112, 114, respectively, regardless of the position of the control spools 120, 122 therein. is held in the position shown in FIG.

Spools 120, 122 extend within housing 106 at cable ends 108, 11, respectively.
0 and is moved to the right or left by the handle 32.

Transmission control bore 112 has an exit port 124 that communicates with high speed transmission 10.
and an outlet port 126 communicating with the low speed transmission 12. outlet port 124,
Intermediately between 126 is an inlet port 128 coupled to connection point 24 (FIG. 1). Discharge port 12
Drain ports 130 and 132 are provided on opposite sides of ports 4 and 126, respectively. Drain ports 130, 132 are also common to brake control bore 114 and communicate with tank 22. Spool 1
20 has lands 134 and 136 and the spool 12
Depending on the position of 0, the land 134 is connected to the port 124,
128 or ports 124, 130, land 136 prevents fluid communication between port 1
26 or 128. When the transmissions are in the neutral position of FIG. 2, lands 134 and 136 block the flow of hydraulic fluid to high and low speed transmissions 10 and 12, and drain ports 130 and 132 communicate with tank 22.

To operate the low speed transmission 12, the handle 32 is moved to the right within the slot 42, which moves the spool 120 to the right and brings the inlet port 128 and the outlet port 126 into communication. In this case, port 1
The drain from port 132 is plugged on the right side of land 136, and the drain from port 130 is blocked on the right side of land 136.
40 is the outlet port 124 and the drain port 130
continues because it is not moved sufficiently to prevent communication between the two. Inlet port 128 to outlet port 1
Flow to 24 is still blocked, but this time by land 222 rather than land 134.

Next, to actuate the high speed transmission 10, moving the handle 32 to the left as viewed in the drawing moves the spool 120 to the left from the position shown. At this time, the land 134 is displaced to the left, blocking communication between the port 124 and the drain port 130, and
Inlet port 128 provides fluid communication to port 124 . Land 136 is axially long enough to continue to block communication to outlet port 126.

Next, the brake control system will be explained.

Brake control bore 114 has a cavity 150 that communicates with connection point 58 via an inlet port 156. An exit port 152 adjacent the void 150
is a void 150 and a drain port 1 extending to the tank.
Brake accumulator 1 located between
74 and the metering pump 16 (FIG. 4).

The spool 122 has a relatively long land 1 in the axial direction.
58, the land 158 typically prevents fluid flow from the cavity 150 to the outlet port 152 under conditions described below and drain port 132.
to drain fluid from the outlet port 152 or to interrupt fluid communication between the drain port 132 and the outlet port 152 and communicate the cavity 150 with the outlet port 152 .

As shown in FIGS. 2 and 3, the land 158 has grooves 160, 1 located opposite to each other on its periphery and extending in the axial direction.
62,164. As shown in FIG. 2, grooves 160, 162, and 164 each open toward cavity 150, with groove 160 being relatively long in the axial direction, groove 162 being of intermediate length, and groove 164 being relatively short.
As shown in FIG. 3, 162 and 164 have relatively large cross sections, and groove 160 has a relatively small cross section.
Also, the cross sections of the three grooves gradually decrease from left to right.

When applying a brake to a winch, it is desirable to be able to apply the brake steplessly to adjust the descent speed. Grooves 160, 162, and 164 act as metering grooves to obtain this control characteristic. That is, as spool 122 moves to the right as viewed in FIG. 2, more fluid flows from cavity 150 through groove 160 to outlet port 152. In the case of a hydraulic release type brake, the greater the fluid flow rate, the greater the degree of brake release.

When the spool 122 is further displaced to the right, the empty space 1
50 and port 152 communicate with each other via a large groove 162, increasing the flow rate. When the spool 122 is further displaced to the right, the empty space 150 and the port 15
Fluid between the two is communicated through all of the grooves 160, 162, and 164.

At this time, the fluid flow rate is maximum and the load drops at the maximum speed. A spring 166 is provided to allow the operator to sense this condition. That is, the cavity 16 where the tip of the groove 164 connects to the port 152
8, the washer 167 will touch the shoulder 17.
Touch 0. As the spool 122 moves further to the right, the spring 166 is compressed and the operator senses that the groove 164 has assumed the maximum speed position.

As shown in FIGS. 1 and 4, the control system of the present invention includes the brake 14 and the outlet port 15 of the control valve 28.
Brake accumulator 1 arranged between
74 , and fluid from outlet port 152 flows through connection point 172 to metering pump 16 and brake accumulator 174 . As mentioned above, the brake to which the present invention is applied is of the type that is engaged by a spring and released by hydraulic pressure, so port 1
The brake 14, which is braked only by pressure oil from the brake 52, has a higher degree of brake release as the fluid pressure increases. As shown in FIGS. 1 and 4, the brake 14 is operated only through the brake accumulator 174.

Next, the configuration and operation of the brake accumulator 174 will be explained.

The brake accumulator 174 includes a housing 178 having a pressure oil inlet 176 communicating with the control valve 28 and a pressure oil outlet 200 communicating with the brake 14.
a plurality of passages 186 communicating with a bore 180 in the housing 178; a piston 182 having a metering orifice 214 at one end and pressed by a pair of springs 188, 190;
a chamber 194 communicating with the bore 180 at one end thereof into which the piston 182 is slidably fitted within the housing 178; and a chamber 198 communicating with chamber 194 via a check valve 196.

The pressure oil regulated through the grooves 160, 162, 164 is sent to the pressure oil inlet 176 of the housing 178. Piston 182, which is pushed to the left by a pair of springs 188, 190, has a thin wall 184 with a plurality of passages 186 perforated therein. Pressure oil is port 1
76 and passes through passage 186 to pocket 1.
92, passage 194, check valve 196,
It communicates with the brake 14 via the chamber 198 and the pressure oil outlet 200.

The brake 14 has a conventional structure consisting of a brake cylinder 206, a spring 204, and a piston 202. When the piston 202 is in the leftmost position in the figure, the brake is fully engaged and is moved to the right by pressure oil. When it is pressed, it is released in proportion to the magnitude of the hydraulic pressure.

Spring 204 opposes fluid pressure within cylinder 206 such that fluid pressure within cylinder 206
piston 20 if insufficient to overcome the force of
2 is biased to the left, and the brake 14 is applied.

As previously described, from the control valve outlet port 152 to the accumulator port 176 and thus to the brake 1
The pressure of the hydraulic fluid applied to spool 122
can be changed by the operator.
That is, as the spool 122 is moved graphically to the right in FIG. 2, more fluid flows from the cavity 150 through the groove 160 to the outlet port 152;
2,164, and the degree of brake release becomes even greater.

Depending on the pressure of the fluid supplied to the brake 14, the brake will be released in one of two ways. If the fluid supply pressure is high, the piston 202
The force applied to is sufficient to completely overcome the force of spring 204. In this case, piston 202 is pushed fully to the right and brake 14 is fully released. When the piston 202 moves significantly, a large amount of hydraulic fluid enters the brake cylinder 206.

The relatively low pressure of the hydraulic fluid is insufficient to completely overcome the force of spring 204, and piston 202 is pushed only a short distance to the right. This piston movement is insufficient to completely release the brake 14, resulting in slippage. In this case, the amount of fluid entering cylinder 206 is relatively small.

When the spool 122 returns to the neutral position as shown in FIG.
32 and thus to tank 22. This lowers the pressure of the fluid delivered to the accumulator port 176 and thus lowers the pressure within the chamber 192.

Next, if pressure oil remains in the accumulator chamber 198 and cylinder 206, the check valve 19
6 prevents backflow of fluid into chamber 192.
Thus, all fluid from brake 14 forces through chamber 198 against the left or end faces 208, 210 of piston 182.

A metering orifice 214 provided in the piston wall 212 connects the chamber 1 through a passage 186.
98 and port 176, the remaining pressure oil is transferred to the metering orifice 214.
and communicates with tank 22 via port 176.

When the pressure oil in the brake 14 is discharged, the fluid in the cylinder 206 is in either a steep drop mode or a slow drop mode depending on the amount.
32 into tank 22.

If the pressure in cylinder 206 is low, such as during a slow descent where the brake is partially released and the load is lowered, it may not be sufficient to fully compress chamber 198 and pressure springs 188, 190 in cylinder 206. . Therefore, slight rightward movement of piston 182 will not compress springs 188, 190 enough to create back pressure in chamber 198 and cylinder 206 that would cause brake 14 to slip. Fluid in chamber 198 and cylinder 206 flows through metering orifice 214 as piston 182 moves slowly to the left, and ultimately returns to tank 22 through control valve 28 .

When the oil pressure in the cylinder 206 is high, such as when the brake is completely released, the flow path of the pressure oil flowing back to the control valve 28 is somewhat different. In this case, the hydraulic pressure in the chamber 198 and the cylinder 206, that is, the hydraulic pressure acting on the end surfaces 208, 210 of the piston, is caused by the spring 18.
8,190 is sufficiently compressed. When the piston end face 208 moves beyond the port end face 216, the piston 182 acts as a relief valve, allowing a large amount of oil to escape from the port 176. As the oil pressure in cylinder 206 and chamber 198 decreases, spring 1
88, 190 again pushes the piston 182 to the left. Springs 188, 190 are configured to create sufficient back pressure in chamber 198 and cylinder 206 to maintain brake 14 slippage on piston 182.

When the piston 182 moves slightly to the left, chamber 1
Communication between 98 and port 176 is interrupted and fluid remaining in chamber 198 and cylinder 206 flows through metering orifice 214 and piston passageway 186. In this manner, metering orifice 214 limits the flow from cylinder 206 and brake 14 is gradually applied.

Industrial Applicability When hoisting up and lowering a load with a winch,
There are two operating modes: one in which the load is lowered a certain distance at maximum speed and then stopped at a specific point, and one in which the load is lowered at a somewhat slower speed.

When the load descends at maximum speed, the spool 12
2 is placed at the rightmost position as seen in Figure 2. High pressure fluid flows from the cavity 150 to the grooves 160, 162, 164.
through to outlet port 152. As shown in FIG. 4, fluid flow from outlet port 152 proceeds to connection point 172 and then to accumulator port 176 and metering pump 16. As shown in FIG.
Once the fluid reaches port 176, it flows through passage 186, pocket 19, chamber 194, check valve 196, and finally port 200 to brake cylinder 206. Chamber 198 is completely filled during this process.

Since the fluid pressure and flow are at maximum, the piston 202 is pushed fully to the right and the brake 14 is fully released. Therefore, the load will drop at maximum speed.

When stopping the lowering of the load, use the spool 122
is displaced to the neutral position shown in FIG. As discussed above, outlet port 152 is then in fluid communication with drain port 132 and thus tank 22. Thus, the fluid in pocket 192 and chamber 194 is drained out of drain port 132. At this time, fluid pressure in chamber 198 and cylinder 206 fully seats check valve 196. Since the check valve is closed, it moves piston 182 against all hydraulic fluid springs 188, 189 which are discharged from brake 14. Chamba 19
8 and cylinder 206, the fluid acting on the piston surfaces 208, 210 is
88,190 to fully compress it.

As piston 182 moves to the right, piston face 208 moves past edge 216 of port 176 and piston 182 acts as a relief valve. Accumulator chamber 198 and cylinder 2
When the pressure of the fluid 06 decreases, the springs 188, 19
0 again pushes the piston 182 to the left to open port 1.
76 will be closed.

As mentioned above, springs 188 and 190 are set to provide sufficient back pressure to maintain brake slippage, so that the spring force is applied to chamber 198 and cylinder 20 to the extent that brake 14 continues to slip.
Piston 182 with sufficient force to create back pressure on 6
Press.

Once chamber 198 is no longer in direct fluid communication with port 176, fluid from chamber 198 and brake cylinder 206 must flow through metering orifice 214. Since the flow rate through metering orifice 214 is restricted, the fluid pressure within cylinder 206 is gradually vented, thus modulating brake engagement and gradually stopping the load.

When the load is lowered slowly, fluid from cavity 150 to outlet 152 passes through less than all of grooves 160, 162, 164. This creates a lower fluid pressure within the brake cylinder 206 than is required to fully release the brake 14. However, the fluid pressure within cylinder 206 is of a magnitude that causes brake 14 to slip and rotate to some extent. piston 20
Since the distance traveled by brake cylinder 206 to the right is small, the amount of fluid contained within brake cylinder 206 is relatively small.

When spool 122 returns to its neutral position, fluid from chamber 198 and cylinder 206 is again applied to the left end of piston 182 by check valve 196.

During slow descent, the volume of fluid acting on the piston faces 208, 210 does not fully compress the springs 188, 190 due to the low pressure and volume of fluid contained in the brake cylinder 206. Therefore, springs 188, 190 are not compressed a sufficient distance to create the back pressure necessary to cause brake 14 to slip as described above.

As is clear from the above structure and operation,
When the load suddenly drops, the high pressure fluid in the chamber 198 and the cylinder 206 fully compresses the springs 188, 190, communicating the high pressure fluid from the pressure oil inlet 176 to the tank 22, and the reaction force of the spring causes the fluid in the cylinder 206 to is from orifice 214 to tank 2
The brake 14 applies a slipping back pressure to the hydraulic pressure in the cylinder 206 until it no longer communicates with the cylinder 206, softening the large shock during a sudden descent, and the springs 188 and 190 gently press the piston 182 when the load descends slowly. This provides an effect unique to the present invention in that the low-pressure fluid in the cylinder 206 is communicated from the orifice 214 to the tank 22, and the brake 14 is gradually applied until the communication is stopped.

In addition, in the embodiment of the present invention, when the pump 20 or the engine does not operate, the accumulator 62
It is equipped with a device to discharge pressure oil from. Fluid from the accumulator 62 is supplied to the spools 122, 14
Drain port 1 to tank 22 by position 0
30, or through an orifice 224 for return through port 128 and pump 20 to tank 22.

As described above, by employing the brake accumulator 174 of the present invention in the winch control device, the braking force is adjusted to soften the impact when the load is suddenly descending, and is not adjusted when the load is descending slowly. Extremely useful in applying the brakes.