JPS6222716Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic switching valve for a central lubrication system.
Specifically, it includes a main piston 7 that switches the direction between the pump communication port and the two main pipe connection ports, and a pilot piston that switches the direction between both ends of the main piston and the pump communication port,
The present invention relates to a hydraulic switching valve for a central lubrication system in which the pilot piston is provided with a detent mechanism (hereinafter referred to as a detent mechanism) as a position holding mechanism and the piston is switched using circuit pressure.

Conventionally, in a lubrication line system using this type of hydraulic switching valve, two pressure reducing valves are attached to the hydraulic switching valve, and the supplied hydraulic pressure is reduced by each of the pressure reducing valves, and the pilot piston of the hydraulic switching valve is Japanese Utility Model Application Publication No. 51-157792 discloses a system in which the piston is switched at a pressure lower than the supply oil pressure, and the supply oil pressure is increased to ensure that lubricated parts at the end are also reliably supplied. Apparently, it has already been proposed.

That is, this lubrication line system is of a double-end type, and as shown in Fig. 5, it has a main piston (not shown) and a day tent mechanism (not shown).
Two main pipe connection ports (not shown) of the hydraulic switching valve 50 are equipped with a pilot piston (not shown) for switching the main piston.
The two main pipes 53 and 54 are connected, and each main pipe 5 is connected separately from the hydraulic switching valve 50.
two pressure reducing valves 55 corresponding to 3 and 54, respectively;
A pressure reducing mechanism 57 having 56 is provided, and each main pipe 5
3 and 54 are respectively reduced by the respective pressure reducing valves 55 and 56 to act on the pilot piston to switch the piston, thereby increasing the supply oil pressure of each of the main pipes 53 and 54. However, the hydraulic pressure applied to the pilot piston can be lowered.

In addition, 51 is a pump, and 52 is its discharge pipe.

In the conventional system configured as described above, separate pressure reducing valves 55, 56 were provided for each of the main pipes 53, 54, so differences in pressure reducing performance due to manufacturing tolerances of the pressure reducing valves 55, 56, etc. There is a problem in that the switching pressure when the pilot piston performs the switching operation changes, making it impossible to completely supply oil from the main pipe 53 or 54 to the parts to be lubricated. In other words, for example, when the hydraulic pressure supplied to one of the main pipes 53 reaches a set value, the pressing force due to the hydraulic pressure reduced by the pressure reducing valve 55 overcomes the holding force of the detent mechanism of the pilot piston, Even if the piston is configured to perform a switching operation, as described above, due to the difference in pressure reduction performance between the pressure reducing valves 55 and 56, for example, the pressure reduction of the other pressure reducing valve 56 is smaller than that of the one pressure reducing valve 55. In this case, in the other main pipe 54 corresponding to the other pressure reducing valve 56,
Before the supply oil pressure reaches the set value, the pilot piston switches and the distribution valve connected to the end of the main pipe 54 does not operate, making it impossible to supply oil to the lubricated area, and conversely, the pressure reducing valve 56
If the pressure reduction is larger, the pilot piston will not switch even if the supplied oil pressure reaches the set value, causing a problem in which the supplied oil pressure will become unnecessarily high.

On the other hand, these problems are solved by the pressure reducing valves 55, 56.
This can be solved by increasing the manufacturing precision of the pressure reducing valves 55 and 56, or by providing adjustment means for each pressure reducing valve 55, 56, but on the other hand,
This does not provide a fundamental solution to the problem, since the manufacturing cost is high and the adjustment work is complicated.

The present invention was devised in view of the above-mentioned conventional problems, and the purpose is to reduce the circuit pressure using one pressure reducing mechanism and apply it alternately to both ends of a pilot piston equipped with a position holding mechanism, thereby reducing the pressure in each main pipe. The purpose of this method is to ensure that lubricated parts at the ends can be reliably lubricated by using exactly the same supply oil pressure for mutually switching the supply between the connection ports.

Therefore, the present invention has a main piston that switches the direction between the pump communication port and the two main pipe connection ports, and a main piston that switches the direction between both ends of the main piston and the pump communication port. In the hydraulic switching valve for a centralized lubrication system, the valve is equipped with a pilot piston and a position holding mechanism is provided on the first pilot piston, and a communication path on which circuit pressure acts is provided, and both ends of the communication path and the first pilot piston are connected to each other. A second pilot piston is provided for switching the direction between the main piston and the main piston, and a circuit pressure is selectively applied to both ends of the second pilot piston by the switching action of the main piston to switch the second pilot piston. and the communication passage is configured to selectively communicate with one end of the first pilot piston, while a pressure reduction mechanism is interposed in the communication passage, the circuit pressure is reduced by the pressure reduction mechanism, and the reduced pressure is applied to the pressure reduction mechanism. act on one end of the first pilot piston,
By reducing the circuit pressure and applying it alternately to both ends of the first pilot piston using a pressure reducing mechanism interposed in the communication path on which the circuit pressure acts, the pilot piston is switched. This made it possible to maintain the supply oil pressure supplied to the main pipes from the two main pipe connection ports at a value that would ensure the operation of the distributing valve at the end.

Hereinafter, embodiments of the present invention will be described based on the drawings.

What is shown in FIG. 1 is a housing A in which a hydraulic switching valve 1 according to the present invention and a pump 2 are integrally assembled.

The hydraulic switching valve 1 is provided within the housing A,
A pump communication port 4 that connects the discharge path 3 of the pump 2 and two main pipe connection ports 5 and 6 that connect the main pipes are provided, and the hydraulic switching valve 1 is provided within the housing A. The two main pipe connection ports 5 and 6
a switching valve portion having a main piston 7 for switching the direction of connection between the main piston 7 and the pump communication port 4; and a first pilot piston 8 for controlling the switching operation of the piston 7; and a switching operation of the first pilot piston 8. The pilot piston 9 has a second pilot piston 9 for controlling the pressure, and a pilot section having a relief valve 10 as a pressure reducing mechanism.

More specifically, the switching valve section has two piston holes 7a and 8 in the housing A, similar to the conventional one.
a, and the three-land type main piston 7 and the four-land type first pilot piston 8 are each slidably housed inside.

Then, the two main pipe connection ports 5 and 6 and the tank ports T and T are respectively opened in the piston hole 7a for the main piston 7, and the main supply path 12 (in addition,
Although not shown, the communication port 4 and the supply path 1
2 through a passage extending perpendicularly to the plane of the paper in FIG. connection port 5,
The direction of the connection with 6 is switched.

Further, the main supply path 12 is connected to the piston hole 8a in which the first pilot piston 8 is housed.
and first pilot passages 13 and 14 communicating with both ends of the main piston 7, respectively, are opened, and a detent mechanism 15 is provided in the first pilot piston 8 as a position holding mechanism to hold the piston 8 in the second position. It is set up. Then, by switching the first pilot piston 8 against the holding force of the detent mechanism 15,
The direction of the main supply passage 12 and the first pilot passages 13, 14 is switched, and furthermore, the main piston 7 is operated by switching the direction.

Note that 16 is a safety valve.

In this embodiment, the pilot section constructed as below is connected to the switching valve section constructed as above.

That is, the housing A is provided with a piston hole 9a for the second pilot piston 9, the 3-land type second pilot piston 9 is slidably housed in the piston hole 9a, and the piston hole 9a is further provided with: A second pilot passage 18 opens a communication passage 17 on which circuit pressure acts, connects this communication passage 17 to the pump communication port 4, and communicates with both ends of the first pilot piston 8, respectively.
19 is opened, and the communication path 17 is opened by the two-way switching valve function of the second pilot piston 9.
The direction of connection between the pilot passage and the second pilot passages 18 and 19 can be changed.

Furthermore, the communication path 17 is provided with the relief valve 1 for reducing the supply pressure at the pump communication port 4 and supplying the reduced pressure to the second pilot piston 8.
0 is inserted.

The relief valve 10 has a valve hole 20.
A valve 21 that opens and closes the communication passage 17 on the inflow side to the
A spring 22 that presses the valve 21 in the closing direction is installed inside the valve. The strength of the spring 22 is determined by the strength of the main pipe 2 connected to the main pipe connection ports 5 and 6.
When the oil pressure supplied to the pilot pistons 9 and 30 reaches a set value, the pressure is reduced by the relief valve 10 to switch the oil supply from the main pipes 29 and 30 to each other, and the oil pressure is applied to the end face of the pilot piston 8. The pressing force is set so as to overcome the holding force of the detent mechanism 15 and cause the piston 8 to switch.

That is, the supplied oil pressure when the relief valve 10 is opened is a pressure corresponding to the resultant force of the holding force of the detent mechanism 15 and the force of the spring 22, and if the force of the spring 22 is strengthened, the holding force of the detent mechanism 15 is increased. It goes without saying that the force can be reduced, but the stronger the force of the spring 22, the higher the supply oil pressure, and the supply oil pressure for supplying oil to long-distance distribution valves can be secured.

Further, both end surfaces of the second pilot piston 9 and the main pipe connection ports 5 and 6 are communicated via third pilot passages 23 and 24, respectively, and the supply pressure acting on the connection ports 5 and 6 is used to connect the second piston to the main pipe connection ports 5 and 6. The pilot piston 9 is operated in a switching manner.

The pump 2 has a pump piston 25 slidably installed in the piston hole 25a, and a check valve 2 in the compression chamber of the piston hole 25a.
6 is connected to the discharge passage 3 which is interposed therebetween. Further, 27 and 28 are tank ports.

FIG. 2 shows a double-pipe, end-type lubrication line system using the hydraulic switching valve 1, in which distribution valves 31 are provided at the main pipe connection ports 5, 6 of the hydraulic switching valve 1. Main pipes 29 and 30 are connected to each other.

Next, the operation when the hydraulic switching valve 1 of this embodiment is used in the lubrication line system shown in FIG. 2 will be explained.

First, a description will be given of the state shown in FIG. 1, that is, the case where the first pilot piston 8 is at the left side position in FIG. 1 and lubricant supply is started from one main pipe connection port 5.

When the pump 2 is operated, the lubricant discharged from the pump 2 passes through the discharge passage 3, reaches the pump communication port 4, and flows into the main supply passage 12 via a passage (not shown). At this time, the first pilot piston 8 is connected to the detent mechanism 15, as described above.
15, the supply oil pressure of the lubricant acts on the left end surface of the main piston 7 in FIG. The piston 7 is held at the right end of the piston hole 7a. As a result, the main supply path 12 and one main pipe connection port 5 communicate with each other, and the lubricant is supplied to the main pipe 29 through the connection port 5.
The lubricant is sent out through each distribution valve 31 and supplied to lubricated parts (not shown) such as sliding parts.

The hydraulic switching valve 1 of this embodiment switches the supply of lubricant from the main pipe 29 to the main pipe 30 by changing the connection direction between the main supply path 12 and the main pipe connection ports 5 and 6 as described below. This is done by switching.

That is, when the supply of lubricant is started in the above state, the second pilot piston 9 has the supply oil pressure of the one main pipe 5 acting on its left end surface via the third pilot passage 23, so that the piston hole 9a The connecting passage 17 communicates with a second first pilot passage 18 communicating with the left end of the first pilot piston 8.

However, the communication path 17 has the relief valve 1
0 is interposed, and the valve 21 of the relief valve 10 is connected to the spring 2.
Since the communication passage 17 is closed by pressing at 0, no supply oil pressure acts on the left end surface of the first pilot piston 8 during lubricant supply. Therefore, during this period, the first pilot piston 8 is held at the right end position by the detent mechanisms 15, 15.

On the other hand, by supplying lubricant from the one main pipe connection port 5, all the distribution valves are operated, and when the supply of lubricant is completed, the supply oil pressure rapidly increases and reaches the set value of the relief valve 10. At this time, the relief valve 10 opens and the supplied hydraulic pressure is reduced by the relief valve 10, and the reduced pressure is applied to the left end surface of the first pilot piston 8 via the second first pilot passage 18.

When the reduced pressure reaches a pressure that causes the first pilot piston 8 to perform a switching operation, that is, when it overcomes the holding force of the detent mechanism 15, the first pilot piston 8 is moved to the right in FIG. It is. As a result, the main supply passage 12 and the other first pilot passage 14 are connected, and supply oil pressure acts on the right end surface of the main piston 7, causing the piston 7 to move to the left. As a result, the main supply path 12 is cut off from communication with the one main pipe connection port 5, and is connected to the other main pipe connection port 6, and is now connected to the other main pipe 30 from the main supply path 12.
At the same time, the second pilot piston 9 is moved to the left to move the second pilot piston 9 to the second first pilot passage 19.
is communicated with the spring 22 side of the relief valve 10.

Further, when switching the supply of lubricant from the other main pipe 30 to the one main pipe 29, it can be done in exactly the same way, and the supply pressure of the lubricant supplied from the other main pipe connection port 6 to the main pipe 30 is as follows. When the set value set by the relief valve 10 is reached, the pressure is reduced by the relief valve 10, and the reduced pressure is applied to the right end surface of the first pilot piston 8, and this reduced pressure is used as the switching pressure of the piston 8. reached,
The pressing force due to the hydraulic pressure is the day tent mechanism 1.
When the holding force of 5 is overcome, the first pilot piston 8 is moved to the left.

Similarly, the connection of the main supply path 12 is switched from the other main pipe connection port 6 to the one main pipe connection port 5, and the connection of the main supply path 12 is switched from the other main pipe connection port 6 to the one main pipe connection port 5 again.
lubricant is supplied to the

Incidentally, the spring 22 of the relief valve 10 in the above embodiment may be provided with an adjusting means, and by doing so, the switching pressure of the first pilot piston 8 can be changed without changing, in other words, the detent mechanism 15 can be changed. The set value of the supply oil pressure can be changed arbitrarily without any trouble.

The hydraulic switching valve of the present invention is of the double-pipe type and
In addition to end-type lubrication line systems, double-pipe and
It can also be applied to loop-type lubrication line systems.

That is, FIG. 3 shows an embodiment in which the hydraulic switching valve of the present invention is used in a double-pipe loop type lubrication line system, and the difference from the double-pipe end type is that the loop has a pair of main pipes 29a and 30a. return side 29b, 3
0b is alternately communicated to both ends of the second pilot piston 9 by the main piston 7, and a communication path 17 on which circuit pressure acts is connected to both ends of the second pilot piston 9. The relief valve 10 is opened and closed, and the open side is
The circuit pressure acting on the primary side of the relief valve 10 is the circuit pressure of the return side main pipe, and the pump discharge pressure acts on the first pilot piston 8. This is different from the embodiment.

Fig. 4 shows an embodiment in which the hydraulic switching valve of the present invention is used in a single-pipe loop type lubrication line system.
The return side 29b of the main pipe 29a is alternately communicated with both ends of the second pilot piston 9 by the main piston 7, and the communication path 17 on which circuit pressure acts is connected to both ends of the second pilot piston 9. , are opened and closed by the piston 9, and
The open side communicates with one end of the first pilot piston 8 via the relief valve 10, and the circuit pressure acting on the primary side of the relief valve 10 is the circuit pressure of the return side main pipe, and is equal to the pump discharge pressure. This is different from the embodiment shown in FIG. 1, in which the

As described above, depending on the formation position of the communication path 17, the circuit pressure acting on the primary side of the relief valve 10 becomes the pump discharge pressure or the return pressure of the return side main pipe, but any circuit pressure good.

Further, in the embodiment described above, a relief valve is used as an example of a pressure reducing mechanism, but a constant difference pressure reducing valve, a constant ratio pressure reducing valve, etc. may be used in addition to the relief valve.

Further, in the embodiment described above, the first pilot piston 8 is held in position by the detent mechanism 15, but instead of the detent mechanism 15, a rack is formed on the first pilot piston 8, and the pinion member that meshes with this rack is moved by a spring. 1st pull
A position holding mechanism may be used to hold the pilot piston 8 in position.

As described above, the present invention has a main piston 7 that switches the direction between the pump communication port 4 and the two main pipe connection ports 5 and 6, and a connection between both ends of the main piston 7 and the pump communication port 4. The first to change direction
A hydraulic switching valve for a centralized lubrication system is provided with a pilot piston 8 and a position holding mechanism 15 is provided on the first pilot piston 8. A communication passage 17 on which circuit pressure acts is provided, and the communication passage 17 and the first pilot piston 8 are connected to each other.
A second pilot piston 9 is provided for switching direction between both ends of the pilot piston 8, and
By selectively applying circuit pressure to both ends of the second pilot piston 9 by switching the main piston 7, the second pilot piston 9 is switched, and the communication passage 17 is connected to the first pilot piston 9. While selectively communicating with one end, a pressure reducing mechanism 10 is interposed in the communication path 17,
Since the circuit pressure is reduced by the pressure reducing mechanism 10 and the reduced pressure is applied to one end of the first pilot piston 8, that is, it is supplied from the two main pipe connection ports 5 and 6 to the main pipes 29 and 30, respectively. The hydraulic pressure applied to the first pilot piston 8 is reduced by one relief valve 10, and the first pilot piston 8 is operated using the reduced hydraulic pressure, so that the hydraulic pressure applied to the first pilot piston 8 can be lowered. This makes it possible to use a daytent mechanism with a very small holding force while increasing the oil supply force.
Moreover, since the switching pressures for mutually switching the lubricant supply from the main pipe connection ports 5 and 6 can be set to exactly the same value, there is an unbalance in the supply oil pressure to the lubricated parts at the ends of the main pipes 30. There is no possibility that this will occur.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is an explanatory diagram of the same lubrication line system, Figs. 3 and 4 are explanatory diagrams of other embodiments, and Fig. 5 is an explanation of a conventional example. It is a diagram. 1...Hydraulic switching valve, 4...Pump connection port, 5,
6... Main pipe connection port, 7... Main piston, 8...
...First pilot piston, 9...Second pilot piston, 10...Relief valve, 15...Detent mechanism, 17...Communication path.

Claims (1)

[Scope of utility model registration request] A main piston 7 that switches the direction between the pump communication port 4 and the two main pipe connection ports 5 and 6, and a first pilot that switches the direction between both ends of the main piston 7 and the pump communication port 4. piston 8
In the hydraulic switching valve for a centralized lubrication system in which the first pilot piston 8 is provided with a position holding mechanism 15, a communication passage 17 on which circuit pressure acts is provided, and the communication passage 17 and the first pilot piston 8 are connected to each other. A second pilot piston 9 is provided for switching the direction between the two ends of the second pilot piston 9, and circuit pressure is selectively applied to both ends of the second pilot piston 9 by the switching operation of the main piston 7. The piston 9 is operated to selectively communicate the communication passage 17 with one end of the first pilot piston 9, while a pressure reduction mechanism 10 is interposed in the communication passage 17, and the circuit pressure is transferred to the pressure reduction mechanism. 10, and the reduced pressure is applied to one end of the first pilot piston 8.