JPS625877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a valve device for a linear or non-linear hydraulic motor designed to move cargo for unloading or unloading, and is connected to a hydraulic supply source through a positioning valve. and on the other hand to the unloading and unloading sides of the hydraulic motor, the pilot-controlled holding valve and the first check valve being arranged in a conduit leading to the unloading side of the hydraulic motor. Moreover, the check valve is arranged so that the holding valve bypasses and communicates with the unloading side of the hydraulic motor, and the pressure liquid from the unloading side of the hydraulic motor is passed through the check valve. The present invention relates to a valve device for holding a load and braking downward, in which flow bypasses the above-mentioned holding valve when the holding valve is open. The valve arrangement according to the invention is primarily used in hydraulic piston-cylinder units of cranes or similar machines, but it can also be used in other applications.

The prior art in this field does not provide a valve system that can not only hold the load safely and reliably, but also control the rate of descent of the load depending on the cylinder load pressure.

It is an object of the invention to provide a valve device capable of performing the functions described above.

The present invention connects one throttle valve and a second check valve in parallel in the conduit leading to the unloading side of the hydraulic motor, and the second check valve is connected to the unloading side of the hydraulic motor. Only the pressure liquid from the unloading side can flow bypassing the throttle valve, while the pressure liquid to the unloading side of the hydraulic motor is configured to flow through the throttle valve; The hold up valve is
The hold-up valve is actuated by hydraulic pressure in a conduit leading to the unloading side of the hydraulic motor, and the hold-up valve is configured to open when the pilot pressure in the conduit reaches a certain value. In addition, the hold-up valve mentioned above has an aperture adjustment degree of
It is established depending on the hydraulic pressure in the conduit between the above-mentioned hold-up valve and the unloading side of the hydraulic motor, and as a result, when the pressure in the conduit increases, the degree of restriction of the throttle valve increases. It is characterized by being formed in such a way that it increases.

By using the valve device according to the invention, loads can be held safely and reliably. The descending speed of the load is automatically established according to the weight of the load, and as the weight of the load increases, the descending speed becomes slower.

In a variant embodiment of the valve device according to the invention:
A pressure limiter is arranged before the throttle valve. By appropriate selection of the components, it is possible to obtain the desired relationship between the weight of the load and the maximum permissible lowering speed.

The invention will now be explained in detail with reference to several preferred embodiments shown in the drawings.

In the figure, reference numeral 1 denotes a valve device for holding a load and braking downward according to the present invention, which is a hydraulic motor, that is, in the illustrated embodiment, a hydraulic piston cylinder unit 2.
It is connected to the unloading side 3 and the unloading side 4 of. Reference numeral 5 denotes a pressure oil supply source such as a pressure oil pump, which supplies the valve 1 via a positioning valve 6 and conduits 7 and 8.
It is connected to the. The valve 1 is connected to the unloading side 3 of the piston cylinder unit 2 by a conduit 9 and to the unloading side 4 through a conduit 10. In the illustrated example, the crane 11 is raised and lowered by the piston cylinder unit 2.

The valve 1 is provided with a variable throttle valve 12, a pilot-controlled hold-up valve 13, and two check valves 14, 15. One check valve 14 is connected in parallel with a throttle valve 12, and these two valves 14 and 12 are connected via a conduit 10 to the unloading side 4 of the piston-cylinder unit 2. Also, the connection of the check valve 14 is such that pressure oil can be discharged from the unloading side 4 of the piston cylinder unit 2, but the discharged oil is always allowed to pass through the throttle valve 12.

The other check valve 15 is connected in parallel with the hold-up valve 13, and these two valves 15, 13 are connected via a conduit 9 to the unloading side 3 of the piston-cylinder unit 2. Therefore, pressure oil can be supplied to the unloading side 3 of the piston cylinder unit 2, but when the valve 13 is open, all the pressure oil passes only through this valve 13 to the unloading side (3) of the piston cylinder unit 2. (pressure side) 3.

A pilot-controlled hold-up valve 13 is controlled in response to oil pressure at point 16. When the current pressure oil value reaches a certain value, the valve 13 is switched to a state where the pressure oil is conducted. Pressure oil then flows through this valve 13, thereby allowing the working arm of the crane 11 to be lowered. The oil pressure at point 17 influences the adjustment value of throttle valve 12. The higher the oil pressure in the conduit 9, that is, the greater the load on the crane 11, the more strongly the throttle valve 12 is throttled.

The operation of the load holding and descending braking valve device 1 according to the present invention described above will be described as follows.
That is, the load (not shown) is transported by the crane 11.
When attempting to raise the positioning valve 6, the valve member of the positioning valve 6 is moved to the left in FIG. Then, the pressure oil is fed from the pressure oil supply source 5 through the conduit 7 and through the check valve 15, bypassing the valve 13 and being fed under pressure. On the other hand, the pressure oil is connected to conduit 1 from the discharge side of the piston cylinder unit.
0 and flows through the check valve 14, the throttle valve 12 and the conduit 8 to the oil reservoir 5'.

When lowering the load, it is done as follows.

At this time, when the valve member of the positioning valve 6 is moved to the right in FIG. At this time, the check valve 14 performs a blocking action, and the flow of pressure oil is restricted and then flows through the conduit 10 into the unloading side 4 of the piston-cylinder unit 2. Exhaust oil from the unloading side 3 of the unit 2 flows through conduit 9 to hold-up valves 13 and 15. The two valves 13 and 15 serve in this case to prevent the flow of oil from the unloading side. The oil pressure in conduit 10, and therefore at point 16, increases to cause the pilot controlled hold up.
When a value is reached such that the valve 13 opens, the pressure oil in the conduit 9 flows through the conduit 7 into the oil reservoir 5', thus reducing the load.

So, when the oil pressure in conduit 9 and therefore at point 17 decreases, the throttle valve 12 is controlled and the load or oil pressure in the piston-cylinder unit 2 increases, and when the oil pressure in conduit 9 increases, the throttle valve 12 is controlled. Increase the oil flow restriction in step 12. Therefore, when the load is large, the load is automatically lowered gradually, and when the load is small, the lowering speed is accelerated. Therefore, by appropriately selecting the constituent members of the throttle valve 12,
It is possible to obtain a desired effective velocity characteristic as a function of the weight of the load.

In this way, the hold up valve 13
The required safety improvement can be achieved by ensuring that the pilot pressure relative to the piston corresponds to the pressure at the point 16 between the throttle valve 12 and the unloading side 4 of the piston-cylinder unit 2. The size of the load is not the only factor that affects the rate of load descent. When the load lowering rate increases without being controlled, the oil pressure in the conduit 10 decreases accordingly, but in such a case, the oil pressure from the unloading side is throttled by the hold-up valve 13. .

Next, a preferred embodiment of the valve device 1 for holding a load and braking downward will be described in more detail with reference to FIGS. 2 to 6. In particular, the throttle valve 12 shown in detail in FIGS. 2 and 3 is provided with a piston 18, which is self-expanding in the longitudinal direction, as shown slightly to the left in FIG. A coil spring 19 is provided. When the load is lowered, the pressure oil flows from the connection 8' of the conduit 8 through the groove 20 into the first annular passage 21 around the piston 18 and then through the coil spring 19 into the second annular passage. 22. The coil spring 19 serves as the only continuous means for connecting the two annular passages 21 and 22. The second annular passage 22 is a separate passage 23 (see Fig. 4).
It communicates with This passage 23 also communicates with a passage 24. Point 16 (see Figure 1)
may be considered to be within this passage 24. From this passage 24, the pressure oil passes through another passage 25 (see FIGS. 2 and 5) to the connection port 10' of the conduit 10.
guided by. Furthermore, another passage 26 (see FIG. 5) extends from the connection port 8'.
In this case, it communicates with the check valve 14, which is closed. What has just been described corresponds to the connection of valves 12 and 14 in parallel with each other as described above with respect to FIG. When lifting a load, the pressure oil flows in the opposite direction. Oil can flow through check valves 14 and 12.

When lowering the load, oil is introduced under pressure from conduit 9 through connection 9' (see FIG. 2). This oil passes through passage 28 and is held up.
It flows into the valve 13. This valve 13 is closed under the conditions shown in FIG. The oil pressure in the passage 24 increases in this case and reaches such a value that it exerts a certain force on the piston 29, and the valve 13 overcomes the force of the spring 30 and is moved. (This corresponds to the situation shown in FIG. 2).

Note that the point 16 shown in FIG. 1 above may be considered to be within the passageway 24. Oil flows from passage 24 to passage 25 (see FIGS. 2 and 5) to connection 10' of conduit 10. A further channel 26 (see FIG. 5) flows from the connection 8' to the check valve 14, which is currently closed. From this point, passage 27 extends into passage 24. The structure just described corresponds to the check valves 12 and 14 connected in parallel in FIG. When unloading cargo, pressure oil flows in the opposite direction. Oil is check valve 1
4 and 12. Oil from conduit 9 flows through connection 9' (FIG. 2) when lowering the load. In this case, oil flows from passage 28 to hold-up valve 13.

This valve 13 is closed in the case shown in FIG. The oil pressure in the passage 24 will then increase and a force will be exerted on the piston 29, which force will move the valve 13 against the force of the spring 30. This situation corresponds to the situation shown in FIG.

When the conical portion 31 of the valve 13 separates from the valve seat 32 on which it has been seated, oil flows from the passage 28 to the hollow chamber 3.
3 and from there into the annular passage 34 of the valve member 13 (see FIGS. 2 and 6).
This annular passage 34 is provided with a radial opening 35 . This opening 35 opens into an annular passage 36 . From there the oil flows through passages 37, 38, 39 and from there into the connection 7' of conduit 7. Then, this connection port 7' and the flow path 39 (second
(see Fig. and Fig. 6), then check valve 15
reach the place. This check valve 1 when the oil is opened
5 and reaches an annular passage 40. This annular passage 40 is connected to the connection port 9' of the conduit 9 and the lateral passage 41.
(See Figure 6). Pressure oil is in conduit 9
through the piston cylinder unit 2 to the unloading side 3. Pressure oil also flows through this lateral passage 41, which is in communication with a passage 43 (see FIG. 3) through a passage 42. This passage 43 is located at the point 17 mentioned above with reference to FIG.
You can think of it as a place where there is.

The position of the piston 18, that is, the degree of adjustment of the throttle valve 12, depends on the oil pressure in the passage 43 and the spring 44 (third
It is determined by the spring pressure in Figure). When the oil pressure in the passage 43 increases, the piston 18 is pushed to the left in FIG. 3, and the throttling of the valve 12 becomes more pronounced. This is because in this case the narrow part of the cut-off surface 19 is at the edge of the annular channel 21. This throttling action is therefore directly proportional to the weight of the load.

Therefore, by appropriately selecting the characteristics of the spring 44 and the shape of the flattened portion 19 of the piston 18, the relationship between the descending speed of the load and the weight of the load can be made as desired. sell.

FIG. 8 shows a modification of the device according to the invention. In this modified embodiment, a constant adjustment type throttle valve 12a
, a pressure limiter 13a, two throttle valves 14a,
15a. Pressure limiter 45 is connected to conduit 7
and 8. This pressure limiter 4
5 has the function of limiting the pressure that the throttle valve 12a receives. In order to ensure that the rate of descent of the load has the desired characteristics as a function of the weight of the load, a pilot controlled shutoff valve 15a is provided in conduit 9, adapted to employ the hydraulic pressure at point 16 as the pilot pressure.
It is placed inside.

In this embodiment, members 12a and 45 are selected as follows. That is, when the pressure of the load increases, the pressure difference between both sides of the throttle valve 12a is set to an appropriate value. In this case, when the load pressure increases, the pilot pressure against the check valve 15a increases. Since the pressure difference between both sides of the check valve 12a is suppressed to an appropriate value, favorable characteristics of the load drop rate are maintained.

The basic configuration of the further variant shown in FIG. 9 is the same as that described with respect to FIG.
5 is arranged. In this case, the operation of the device of this example is as follows. That is, the pilot pressure on the hold-up valve 13 decreases as the weight of the load increases. In this case, the throttling ratio is changed to obtain the desired load drop rate as a function of the load pressure, so that when the load pressure increases, the pressure oil flow rate decreases significantly. The regulation of the throttle valve 12 is controlled for this purpose by the pressure in the conduit 9.

FIG. 10 shows yet another embodiment. The basic configuration of the device in this example is almost the same as that explained with reference to FIG. 9, but the difference is that it is equipped with a valve 12c for rapid throttling and a pressure limiter 45c. be. As a result, the limiting pressure decreases in the case of an increase in the load pressure. That is, the hydraulic pressure at point 17 is detected, and the adjustment value of the pressure limiter 45c is changed accordingly, so that when the load pressure increases, the limiting pressure decreases accordingly. In this way too, the desired effect of the valve is achieved.

A modified embodiment of the pressure limiter 45c of the above-described embodiment shown in FIG. 10 is shown in FIG. In this example device, conduit 8 is connected to passageway 46 . A rod member 47 is provided in the lower part of this passage 46, the end of which contacts a piston 48 or a conical member 49. A conical member 49 of the piston 48 is arranged on one side of the passage 46. and the piston 48 is in the passage 5
It is disposed so as to be movable from side to side within 0, and its narrowed portion 47 can enter and exit the passage 51,
A conical portion 49 partially enters into this passage 51 . A passage 52 is disposed in contact with the opposite end of the piston 48, so that the piston 48 is connected to the two passages 52 and 4.
6 are separated from each other. The conical portion 49 is constructed with a portion of a member 53, which is disposed within the passageway 54. Reference numeral 55 is a spring, which is press-fitted to the above-mentioned member 53, and normally this conical portion 49 closes the passage 51. The passage 54 also communicates with the passage 56.

The pressure limiter 45c described above operates as follows.

The same hydraulic pressure is present in the passages 56 and 54 as in the conduit 7. This oil pressure cooperates with the force of the spring 55 acting towards the conical part 49 so that the part 49
1 is held in a crimped state so as not to open, so the passage 51 is normally closed. As previously mentioned, since the same pressure is present in passages 46 and 51 as the hydraulic pressure in conduit 8, this pressure pressurizes section 49 to close passage 51 and causes piston 48 to close passage 52. ing. The cross-sectional area of the passage 51 is selected to be larger than that of the passage 50, and the piston 48 and the section 50 are rigidly connected to each other, so that when taken together, the oil pressure in the passage 46 is The drop force acts to the left in Figure 11. The oil pressure in passage 51 is the same as the oil pressure at point 17 in FIG. This oil pressure acts to open the valve and pressure oil flows from conduit 8 to 7. This limits the oil pressure in the conduit 8. The permissible oil pressure in the conduit 8 is therefore dependent on the load pressure; the higher the load pressure, the lower the permissible oil pressure in the conduit 8, which of course leads to favorable outcomes. Thus, the pressure limiters 8 and 9 used in the apparatus shown in FIGS. 8 and 9 can be used similarly to the pressure limiter 45c described above, but this pressure limiter has a simpler structure. It can be done. This is because there is no need to use any pilot oil pressure at point 17.

By using the above-described device of the present invention, various advantages can be obtained as described below.

Since the rate of descent of the load is controlled by the load pressure, the unloading capacity of the crane can be increased without violating the required standards, such as those specified in the West German standard DIN 15068.

As can be seen from the above explanation, if the valve device of the present invention is used, the dynamic unloading capacity will be increased compared to the known example.
It is possible to create a crane that is 20-30% larger.

Since a throttle valve piston is installed on the unloading side 4 of the piston cylinder unit 2 instead of the unloading side 3, the pressure is maintained and controlled within the piston cylinder unit when lowering the load. There's no need to tighten it.

Further, the valve device of the present invention can reliably hold a load, and there is no oil leakage. Further, as shown in FIG. 7, the whole or essential parts of the load holding and braking valve device 1 can be directly disposed at the piston cylinder unit 2.
That is, by disposing the hold-up valve 13 together with the hold-up valve 13 on the unloading side 3 of the unit 2, an intermediate conduit can be omitted. In this way, accidents caused by dangerous pipe bursts can be prevented.

The above-described embodiments are merely illustrative, and the gist of the present invention should not be limited thereto; it is also possible to easily replace linear hydraulic means such as unit 2 with rotary hydraulic means. However, it can be easily carried out by those skilled in the art if necessary, so
Its illustration is omitted.

[Brief explanation of the drawing]

FIG. 1 is a piping diagram of a valve device according to the present invention used in a crane. 2 is a longitudinal sectional view of an embodiment of the valve device taken along the line - from FIGS. 4 to 6, and FIG. 3 is a longitudinal sectional view of the valve device taken along the line - from FIGS. FIG. 2 is a vertical cross-sectional view of one embodiment. Figure 4,
5 and 6 are cross-sectional views taken along the lines -, -, - of FIGS. 2 and 3, respectively. FIG. 7 is a piping diagram of a modification of the valve device according to the present invention. 8, 9 and 10 show piping diagrams of several variations of the valve arrangement. FIG. 11 is a cross-sectional view of a pressure limiter used in a valve system. 1... Valve device for load retention and valve downward braking, 2... Hydraulic piston cylinder unit, 3... Unloading side, 4
...Unloading side, 5...Pressure oil supply source, 6...Positioning valve,
7, 8, 9, 10... Conduit, 12... Throttle valve, 13...
Hold up valve, 14... check valve.

Claims (1)

[Claims] 1. A valve device for a linear or non-linear hydraulic motor designed to move a load for unloading or unloading, which is connected to a hydraulic pressure source via a positioning valve. On the other hand, a pilot-controlled holding valve and a first check valve connected to the unloading side and the unloading side of the hydraulic motor are disposed in a conduit leading to the unloading side of the hydraulic motor, and The stop valve is arranged to bypass the holding valve and communicate with the unloading side of the hydraulic motor, and the pressure fluid from the unloading side of the hydraulic motor is connected to the unloading side of the hydraulic motor when the check valve is open. In the case where the flow bypasses the holding valve of the hydraulic motor 2, one throttle valve 12 and the second check valve 14 in the conduits 8 and 10 leading to the unloading side of the hydraulic motor 2 are connected in parallel. This second check valve 14 allows only the pressure fluid from the unloading side of the hydraulic motor 2 to flow bypassing the throttle valve 12; The hold-up valve 13 operates the pressure liquid in the conduit on the unloading side of the hydraulic motor 2 to cause the hold-up valve to flow through the throttle valve. The valve 13 is configured to open when the hydraulic pressure in the conduit reaches a certain value as a pilot pressure, and the throttle valve 12 is configured such that its throttle adjustment degree is adjusted to the hold level as described above. established depending on the hydraulic pressure in the conduit 9 between the up valve 13 and the unloading side 3 of the hydraulic motor 2, so that when the hydraulic pressure in the conduit 9 increases, the throttle valve 1. A valve device for load holding and downward braking, characterized in that the device is configured to increase the degree of restriction of 12. 2. The load holding and downward braking valve according to claim 1, wherein the pressure limiter 18 limits the hydraulic pressure in the conduit between the throttle valve 12 and the positioning valve 6. Device. 3 The pilot-controlled hold-up valve 13 is such that it is actuated by the hydraulic pressure in the conduit 10 between the unloading side 4 of the hydraulic motor and the throttle valve 12. A valve device for load holding and downward braking according to claim 1 or 2, characterized in that the valve device is configured as follows. 4. The load holding and lowering device according to any one of claims 1 to 3, characterized in that the hold up valve 13 is directly connected to the unloading side 3 of the hydraulic motor 2. Valve device for braking. 5 The pressure difference between both sides of the throttle valve 12 is
is established depending on the hydraulic pressure in the conduit 9 between the up valve 13 and the unloading side 3 of the hydraulic motor 2, so that when the hydraulic pressure in the conduit 9 increases, the Claim 1, characterized in that the device is configured such that the pressure difference between the
The valve device for load holding and downward braking according to any one of Items 1 to 4. 6 Hold/hold the pressure difference between both sides of the throttle valve 12.
The load according to any one of claims 1 to 5, characterized by comprising a member that is controlled by the pilot pressure to the up valve 13 and the valve opening pressure to the pressure limiter 18. Valve device for holding and lowering braking. 7 The pressure limiter (45c, FIG. 10) is actuated by the hydraulic pressure in the conduit 9 between the hoard up valve 13 and the pressure side of the hydraulic motor 2, so that the pressure limiter (45c, FIG. 10) Claim 2 is characterized in that when the oil pressure increases, the permissible oil pressure in the conduit between the throttle valve 12 and the positioning valve 6 is limited to a low value. Valve device for load retention and downward braking.