JPS608234Y2 - Hydraulic switching valve for two main pipe loop type central lubrication system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic switching valve for a two-tube loop type central lubrication system.

Generally, this hydraulic switching valve connects a pump port P connected to a pump line 1 to two main supply pipes 2 and 2, as shown in FIG.
The main piston 4 alternately switches to one of the supply ports t'Lttt'2 connected to the pump line 1, and the main piston 4 is operated by the pressure of return oil from the main supply pipe 2 or 3 connected to the pump line 1,
It has a pilot piston 5 that controls switching of the main piston 4, a pinion gear 60 that is interlocked with the pilot piston 5, and a switching pressure setting mechanism 6 that regulates the operation of the pilot piston 5.

The pilot piston 5 is provided with two main port operation ports 7.8 that communicate with both rear chambers of the main piston 4, and one of these ports 7.8 is operated by the operation of the pilot piston 5 to operate the pump. Through communication with the pump port P, pump pressure is applied to one of the rear chambers on both sides of the main piston 4, and the main piston 4 is switched. .

However, in the conventional hydraulic switching valve, as shown in FIGS. 1 and 72, the main piston operating port 7.8 is communicated with the pump line P via a gear chamber 61 that accommodates the pinion gear 60. That's what I do.

Therefore, pump pressure is constantly applied to the gear chamber 61, so that the outer periphery of the shaft 62 provided with the pinion gear 60 and the inner periphery of the shaft support hole 11 of the valve body 10 that supports the shaft 62. A sealing material 63 such as an O-ring is provided between the valve body 10 and the lubricant introduced into the gear chamber 61 from the gear chamber 61 to the outside through the support hole 11 that opens to the outside of the valve body 10. This prevents leakage.

Further, as is clear from FIG. 2, the shaft 62 supporting both ends of the pinion gear 60 has the same diameter so that no thrust force is applied to the shaft 62 due to pump pressure.

However, since the sealing material 63 is interposed between the shaft 62 that rotates together with the pinion gear 60 and the shaft support hole 11 that is in a stationary state, it becomes a rotational resistance of the pinion gear 60, and furthermore, the sealing material The rotational resistance caused by the material 63 changes depending on the clearance between the shaft 62 and the shaft support hole 11, the cross-sectional area and material of the sealing material 63, and since pump pressure is acting on the sealing material 63, This change in pump pressure also causes the rotational resistance to change.

For this reason, the switching pressure set by the switching pressure setting mechanism 6 changes in response to the change in rotational resistance, resulting in incomplete supply of lubricant or the pilot piston 5 becoming inoperable. There was a problem in that the main pipes 2 and 3 could not be switched, resulting in a supply failure, and there was also a problem in durability.

In FIG. 2, reference numeral 64 denotes a limit arm that is keyed to the upper end of the shaft 62, which protrudes upward from the support hole 11 of the valve body 10. A limit spring 67 is interposed between the tip of the valve body 10 and an adjusting body 66 provided on a cover 65 fixed to the upper part of the valve body 10.

Further, a straight line connecting the support point of the limit spring 67 on the limit arm 64 and the support point on the adjustment body 66 is offset from the center of the shaft 62, and the limit spring 67 64 so as to be switchably biased to one of two swing positions.

That is, when the limiting arm 64 swings from its first position against the limiting spring 67 due to the rotation of the shaft 62 due to the rotation of the pinion gear 60, the straight line of the limiting spring 67 is aligned with the shaft. 62, the limit arm 64 is biased to the second position by the limit spring 67, and when swinging from the second position, the straight line crosses the center of the shaft 62. and,
It is urged to the first position again.

Further, the limiting spring 67 is used to set the switching limiting force, that is, the switching pressure of the hydraulic switching valve, and can be freely set by a pressure adjusting screw 68 screwed into the adjusting body 66.

Therefore, the present invention was devised in view of the above-mentioned problems in the hydraulic switching valve having the switching pressure setting mechanism configured as described above. To provide a hydraulic switching valve that can maintain switching pressure at a desired set pressure regardless of changes in pump pressure, ensure lubricant is always supplied to lubricated parts, and improve durability. be.

That is, the present invention has a main piston that switches the pump port connected to the pump line to one of the supply ports connected to the main supply pipe, a pilot piston, and a pinion gear that interlocks with the pilot piston, and controls the operation of the pilot piston. A switching pressure setting mechanism for regulating the switching pressure is provided, and a return port connected to the main supply pipe is provided in the rear chambers on both sides of the pilot piston. A hydraulic switching valve is provided with a piston operating port and is configured to alternately switch the pump line to the main pipe by the pressure of return oil. A gear chamber accommodating a pinion gear is open to the tank line, and pressure ports are provided on the outside of the main piston operating port, and each of these pressure ports is connected to the pump line through a communication path,
The reciprocating movement of the pilot piston causes one of the pressure ports to alternately communicate with one of the main piston operation ports that is paired with the pressure port.

Embodiments of the hydraulic switching valve of the present invention will be described below based on the drawings.

The basic structure of the hydraulic switching valve of the present invention is similar to the conventional hydraulic switching valve shown in FIG. 1, and includes a main piston 4, a pilot piston 5, and a switching pressure setting mechanism 6. .13, each of the pistons 4 and 5 is slidably housed therein, and a shaft support hole 11 is formed between the sliding grooves 12 and 13, and the pinion gear 60 of the setting mechanism 6 is inserted into this support hole 11. A pump port P connected to the pump line 1 is provided in the valve body 10, while the pinion gear 60 is meshed with and interlocked with the rack of the pilot piston 5.
A supply port "tt L2" and a return port RHR2 are provided to connect the main supply pipes 2 and 3, and the pump port 1 and the supply ports Lx and L2 are opened to a sliding groove 12 in which the main piston 4 is housed, and , said return port R1,
R2 is a sliding groove 13 in which the pilot piston 5 is installed.
The sliding groove 1 opens into the rear chambers 16 and 17 provided on both sides of the sliding groove 1 and is further located inside the return ports R1 and R2.
3, rear chambers 18 on both sides of the main piston 4;
．． A main piston operating port 7.8 communicating with the main piston operating port 7.8 is provided, and the pilot piston 5 is operated by the pressure of the return oil returning to one of the return ports R□ and R2. The communication between the main piston 4 and the rear chambers 18 and 19 is switched to operate the main piston 4, and the pump line 1 is alternately switched to the main pipes 2 and 3.

The present invention provides a hydraulic switching valve for a two-tube loop type central lubrication system configured as described above, in which a tank port 23 or 23 a, 23 b is opened in the center of the pilot piston 5 to be connected to the tank line T. Then, the gear chamber 61 accommodating the pinion gear 60 is connected to the tank line T.
The main piston operating port 7
．． 8 are provided with pressure ports 24 and 25, respectively, and these pressure ports 24 and 25 are connected to the pump line 1 through a communication passage 26, and the reciprocating motion of the pilot piston 5 causes the pressure ports 24 and 25 to be opened. One of the main piston operating ports 7.8 is alternately connected to one of the main piston operating ports 7.8 which is paired with the pressure ports 24, 25.

The one shown in FIGS. 3 to 5 is a so-called differential type in which the main piston 4 is of a four-land type, and the operating direction of the main piston 4 and the operating direction of the pilot piston 5 are opposite. A pair of tank ports 23a*23b connected to the tank line T are opened in the center of the sliding groove 13 that houses the pilot piston 5, and four lands 51 are provided on the pilot piston 5. - 54, the gear chamber 61 is opened to the tank line T through one of the tank ports 23a, 23b selected by the inner land 52, 53,
The pressure port 24.25 opens outside the main piston actuating port 7.8 into the travel path of the outer land 51.54 of the pilot piston 5, and by means of the outer land 51.54 the pressure port 24 and 25 are alternately communicated with one of the main piston operating ports 7.8.

In addition, in FIGS. 3 to 5, 27.28 is a tank port that opens into the sliding groove 12 that houses the main piston 4, and is connected to the inner port 42.4 of the main piston 4.
3 communicates with one of the supply ports 2.3, ie, the supply ports 2 and 3 that do not communicate with the pump port 1, and the main supply pipe L1.3 that does not supply lubricant. One side of L2 is opened to the tank.

Further, 29.30 is a communication port that opens into the communication path of the outer lands 41, 44 in the main piston 4 and communicates with the tank ports 27, 2B through the outer lands 41.44. It communicates with the rear chambers 16 and 17 of No. 5.

Further, 31 is a rod provided on the main piston 4, the tip of which projects outward from the valve body 10, communicates with a limit switch LS provided externally, and detects the switching state of the main piston 4. That's what I do.

Therefore, the state shown in FIG. 3 is that the pump port P
, switch to the supply port pile of supply main pipe 2, and connect the supply port L
2 is communicated with the tank port 28, and lubricant is supplied to the lubricating portion 32 via the main supply pipe 2 via the distribution valve 33, and the return oil of the main supply pipe 2 is connected to the return port (Ri). The pressure port 25 communicates with the right back chamber 19 of the main piston 4 via the main piston operating port 8. and
The main piston 4 is positioned to the left due to pump pressure.

In this state, when the supply to the lubricating portion 32 is finished,
In the right side rear chamber 17, the pilot piston 5
The pressure of the return oil acting on the switch increases, and the switching pressure set by the switching pressure setting mechanism 6 (for example, 50
kg/al), the pilot piston 5 resists the limit spring 67 (see FIG. 2) of the setting mechanism 6.
moves to the left in FIG. 3 and reaches the position shown in FIG.

Therefore, the right rear chamber 19 of the main piston 4 is
The main piston operating port 8 communicates with the tank port 23b via the main piston operating port 8.
The pressure port 25 that was communicating with the pilot piston 5
is closed by the outer land 54 of the outer land 51 .
The pressure port 24, which had been closed, is now in communication with the main piston operating port 7, which communicates with the left rear chamber 18 of the main piston 4, and the pump line 1 is connected to the left rear chamber 18 of the main piston 4. Under pressure, the main piston 4 will move to the position shown in FIGS. 4-5.

As a result, the supply port L of the main supply pipe 2 is opened to the tank port 27, and the pump line 1 is switched to the supply port h of the main supply pipe 3. lubricant is supplied.

When the supply from the main supply pipe 3 is completed, the main piston 4 is again switched to the position shown in FIG. 3 through the above-described operations, and the above-described operations are repeated thereafter.

Further, in the state shown in FIG. 5, due to the switching operation of the main piston 4, the right rear chamber 17 of the pilot piston 5 communicates with the tank port 28 via the communication port 30, and also communicates with the tank port 28 via the communication port 30. piston 5
The left rear chamber 16 of the main piston 4 is closed by the outer land 41 of the main piston 4.

In the embodiment described above, the gear chamber 61 accommodating the pinion gear 60 is always open to the tank line T via either the tank ports 23ay or 23b. Unlike the conventional example shown in the figure, there is no need to provide a sealing material 63, and rotational resistance due to the sealing material 63 is not applied at all.

Moreover, since pump pressure does not act on the gear chamber 61, even if the pump pressure fluctuates, the rotational resistance acting on the shaft 62 via the sealing material 63 changes as in the conventional example described above, and the setting mechanism The switching pressure set in step 6 never changes, and the main supply pipe 2 always maintains the set pressure.
．． 3 switching becomes possible.

Incidentally, in the embodiment described above, the return ports R1 and R2 are provided in a weir shape with respect to the supply port L1=L'l provided in the valve body 1o, but as shown in FIG.
A supply line 34 continuous with the supply ports L□ and L2
．． 35 are provided so that these supply lines 34,35 cross within the valve body 10 and are connected to the supply ports L1.35. L2 and the return ports R□, R2 may be arranged adjacent to each other for each main pipe 2, 3.

By doing so, the main pipes 2 and 3 do not need to cross each other.

Further, in FIG. 6, reference numerals 55 and 56 are pressure balance grooves provided in the middle of the outer lands 51 and 54 of the pilot piston 5.

Further, in the above embodiments, the main piston 4 is of a 4-land type, but it may be of a 3-land type as shown in FIG. 7, or of a 5-land type as shown in FIG. 8.

Furthermore, although each of the above-mentioned embodiments is of a differential type in which the operating direction of the main piston 4 and the operating direction of the pilot piston 5 are opposite to each other, a synchronized type in which the operating directions of the main piston 4 and the pilot piston 5 are in the same direction may be used.

In this case, as shown in FIG. 9, the tank line T
The gear chamber 61 is opened to the tank line T through the tank port 23, which is connected to the pressure port 24.
25 on the outside of the main piston operating port 7.8, and between the inner raw lands 52, 53 and the outer land 5.
1.54, and the inner lands 52 and 53 allow the pressure ports 24 and 25 to alternately communicate with one of the main piston operating ports 7.8. be.

In addition, the main piston 4 shown in FIG. 9 has a 5-land type and a pump port P is provided at the center of the waist, but as shown in FIG. Two pump ports P□, P2 may be provided in the pump, or it may be a 4-land type as shown in Figures 11 and 12, or a 3-land type as shown in Figures 13 and 14. .

In FIG. 14, 45.46 indicates the outer land 41.
44 is a pressure balance groove provided in the middle.

In the embodiment described above, the lubricant in the back chamber 18 or 19, which is the pressurized side of the main piston 4, is placed through the small diameter part of the pilot piston 5, and the tank ports 23, 23a, 2
3b, but if it is opened to the tank port from the small diameter part of the pilot piston 5 via the gear chamber 61 through the gap between the shaft 62 and the shaft support hole 11, as shown in FIG. 15, it will be opened to the tank. The pinion gear 60, shaft 62, etc. can be lubricated using the lubricant.

It goes without saying that the gap between the shaft 62 and the support hole 11 is formed to such an extent that no back pressure is applied.

As described above, the present invention provides a gear chamber 61 that accommodates the gear chamber 60 that accommodates the pinion gear 60 of the switching pressure setting mechanism 6.
Since it is always open to the tank line T via the tank port 23 = 23aw 23b, the pinion gear 6
There is no need to provide a sealing material 63 on the shaft 62 of 0,
Therefore, as in the conventional case, a sealing material 63 is attached to the shaft 62.
Since no rotational resistance is applied to the gear chamber 61, and no pump pressure is applied to the gear chamber 61, there is no change in rotational resistance or change in switching pressure due to fluctuations in pump pressure. Therefore, the switching pressure can be maintained at the set pressure regardless of fluctuations in the pump pressure, and the switching pressure can be set accurately.

Therefore, the lubricant can always be reliably supplied to the lubricated parts, and the conventional problem of inability to supply the lubricant can be solved. Furthermore, since the sealing material 63 does not need to be used, durability can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing a hydraulic switching valve used in a conventional two-tube loop central lubrication system, Fig. 2 is a longitudinal sectional view of the same conventional example, and Fig. 3 is a schematic cross-sectional view of the hydraulic switching valve of the present invention. FIGS. 4 and 5 are schematic sectional views showing a state in which the operation of FIG. 3 has progressed, and FIGS. 6 to 15 are schematic sectional views showing other embodiments. . 1... Pump line, 2, 3... Main supply pipe, 4... Main piston, 5...
Pilot piston, 6...Switching pressure setting mechanism, 7, 8...Port for main piston operation, 1
6,17...Rear chamber of pilot piston, 1
8, 19... Rear chamber of main piston, 23,
23a, 23b...tank port, 24, 25
......Pressure port, 26...Communication path, 6
0...Pinion gear, 61...Gear chamber, P...Pump port, l,, L,...
・Supply port, R1, R2-・・・Return port, T
...tank line.

Claims (1)

[Scope of utility model registration request] It has a main piston 4 that switches the pump port P connected to the pump line 1 to one of the supply ports L and L connected to the main supply pipes 2 and 3, a pilot piston 5, and a pinion gear 60 that interlocks with the pilot piston 5. A switching pressure setting mechanism 6 for regulating the operation of the pilot piston 5 is provided, and return ports R1 and R2 connected to the main supply pipes 2 and 3 are provided in the back chambers 16 and 17 on both sides of the pilot piston 5. Port R1,
Inside R2, there are rear chambers 18 on both sides of the main piston 4.
, 19 is provided, and the pump line 1 is connected to the main pipe 2 by the pressure of return oil.
, 3, in a hydraulic switching valve that alternately switches between
A tank line T is connected to the center of the pilot piston 5.
Tank port connected to 23 = 23at 23b
A gear chamber 6 is opened to house the pinion gear 60.
1 is open to the tank line T, and pressure ports 24 and 25 are provided on the outside of the main piston operating port 7.8, respectively.
5 is connected to the pump line 1 through a communication path 26,
By reciprocating the pilot piston 5, one of the pressure ports 24, 25 is alternately communicated with one of the main piston operating ports 7.8 that is paired with the pressure port 24 or 25. A hydraulic switching valve for a two-tube loop type central lubrication system featuring: