JP2515790Y2 - Pressure regulating valve - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a construction machine, more specifically, to a hydraulic swing drive device that requires extremely smooth start-up, ultra-fine movement operation, and stop performance like a crane truck. The present invention relates to a pressure control valve.

[Prior Art] As a conventional pressure adjusting valve of this type, there is Japanese Utility Model Laid-Open No. 1-141972 by the same applicant as the present application, which will be described with reference to FIG.

The high pressure chamber 20 and the low pressure chamber 21 formed in the housing 25 include a sleeve 26 that is screwed into a screw provided in the housing 25, and a sheet 22 that is attached to one end of the sleeve 26 and pressed against the side surface of the low pressure chamber 21. The oil passage of the seat 22 is provided in the inner diameter portion 27 of the sleeve 26.
Liquid-tightly separated by a poppet 23 that freely slides to open and close 44 and receives a pressing force of a compression spring 29 and abuts against the seat 22.

The inner diameter portion 27 of the sleeve 26 has a poppet 23 at one end and a piston 31 slidably fitted at the other end, and a compression spring 29 is provided between the poppet 23 and the piston 31.
The poppet 23 is constantly pressed against the oil passage 44 of the seat 22, and the piston 31 is pressed against the inner end surface of the cap 33 at the other end of the sleeve 26.

The piston 31 is composed of a small diameter portion whose outer diameter slides on the inner diameter portion 27 of the sleeve 26 and a piston shoulder portion 32 having a diameter larger than the inner diameter portion 27, and the pressing force of the compression spring 29 and the piston back pressure. The pressure oil acting on the chamber 43 axially slidably and liquid-tightly supports the inner diameter portion 27 of the sleeve 26 within a distance G between the piston shoulder portion 32 and the stopper portion 28 of the sleeve 26. Has been done.

A flow control valve with pressure compensation is arranged to control the flow rate of the pressure oil introduced from the high-pressure chamber 20 to the piston back pressure chamber 43. Here, as shown in the figure, the flow control valve with pressure compensation has a piston 31. The piston 31 is disposed coaxially with the high pressure chamber 20, and is configured to guide the pressure oil of the high pressure chamber 20 through the inside of the poppet 23 and the inner diameter portion 45 of the piston 31 to the piston back pressure chamber 43. A pressure compensating spool 34 is slidably provided in an inner diameter portion 45 of the oil chamber, and has oil chambers 37 and 39, an orifice 38 and a lateral hole 40 that connect the both chambers, and the oil chamber 39 and the piston 31. A compression spring 35 provided between the oil chamber 46 and the inner oil chamber 46 presses the rod portion 24 integrally formed with the poppet 23. A through hole 36 is provided inside the rod portion 24 so as to connect the oil passage 44 of the seat 22 and the oil chamber 37 of the pressure compensation spool 34.

The oil chamber 39 in the pressure compensating spool 34 and the oil chamber 46 in the piston 31 communicate with the groove 41 provided in the inner diameter portion 45 of the piston 31 through the lateral hole 40, and from the groove 41 through the oil passage 42 to the piston. It communicates with the back pressure chamber 43. As shown in FIG. 5, the lateral hole 40 is formed from a groove 41 opposed to the pressure compensation spool 34 by sliding the pressure compensating spool 34 against the compression spring 35 (to the right in the drawing) by the pressure oil from the high pressure chamber 20. The positional relationship is such that the passage is narrowed to form a narrowed passage, and the flow rate of the pressure oil is adjusted.

FIG. 3 shows an example in which the pressure regulating valve as described above is used in a hydraulic circuit of a construction machine having a revolving structure, 12 is a pressure regulating valve, 13 is a revolving motor, and 14 is a revolving structure.

In the pressure control valve having such a configuration, the high pressure chamber 20
When the internal pressure rises, the pressure oil acts on the poppet 23 with a pressing force corresponding to the area difference (d1-d2) between the cross-sectional area d1 of the oil passage 44 and the cross-sectional area d2 of the rod portion 24, causing the compression spring 29 to move. The poppet 23 is pushed open by overcoming the pressing force to try to flow from the high pressure chamber 20 to the low pressure chamber 21. However, the pressure increase in the high-pressure chamber 20 is instantaneously transmitted to the oil chamber 37 because the through hole 36 is a relatively large conduit, but communicates with the oil chamber 39 only through the orifice 38. Therefore, there is a time delay in increasing the pressure in the oil chamber 39. In other words, the pressure in the oil chamber 37 becomes higher than the pressure in the oil chamber 39 by the time delay of the pressure rise, and therefore the pressing force due to this differential pressure overcomes the pressing force of the compression spring 35 and pressure compensation is performed. The spool 34 is moved to the right toward the oil chamber 46 in the figure, and is balanced at a position where the pressing force due to the differential pressure and the pressing force of the compression spring 35 are balanced, resulting in the state shown in FIG. Since 40 forms a narrowed passage with respect to the groove 41 of the inner diameter portion 45 of the piston 31 to form a narrowed passage, the amount of pressure oil flowing into the piston back pressure chamber 43 is small, and the increase in pressure is caused by the high pressure chamber. Compared with the pressure increase in 20, the flow rate of the pressure oil into the piston back pressure chamber 43 is constant over time, so the poppet 23 is the initial set pressure of the compression spring 29, that is, the piston. When the right end of 31 starts contacting the inner surface of cap 33, The pressure oil in the pressure chamber 20 is a through hole 36, an oil chamber 37, an orifice 38, an oil chamber 39, and a lateral hole for a variable throttle.
As it flows into the piston back pressure chamber 43 through the 40, groove 41, and oil passage 42, it gradually overcomes the pressing force of the compression spring 29 and gradually moves to the left in the figure, and the shoulder 32 of the piston 31 stops the sleeve 26. It stops at the position where it abuts the portion 28.

In this way, the pressure is gradually reduced during smoothing to perform smooth braking, the pressure rise is smooth, and even if the final operating pressure is set high, there is little shock when the inertial body is stopped and it can be done in a short time. Since it can be controlled, it is a pressure regulating valve suitable for hydraulic braking of revolving structures of construction machinery.

[Problems to be Solved by the Invention] As described above, in the pressure regulating valve as shown in Japanese Utility Model Laid-Open No. 1-141972, the pressure rising process smoothly rises with a comparatively gentle gradient. Although the shock at the time of starting and stopping the revolving structure is greatly reduced,
This is not always sufficient for a machine such as a crane truck that requires ultra-fine movement operation when starting and stopping, and which requires a faster movement after starting movement.

Therefore, an object of the present invention is to provide a machine such as a crane truck that requires a faster movement after starting the ultrafine movement operation only when starting / stopping during turning operation, and when starting / stopping when the ultrafine movement operation is required. Raise the pressure very slowly,
For the subsequent quicker operation, the pressure increasing valve is changed to provide a pressure adjusting valve for increasing the pressure at a steeper angle.

[Means for Solving the Problems] The present invention is to solve the above problems, and one end of the pressure regulating compression spring (29) of the pressure regulating valve is connected to the high pressure chamber (20) and the low pressure chamber (21). The other end of the poppet (23) for opening and closing the space is brought into contact with one end surface of the piston (31) which is slidable within the specified stroke (G), and is brought into contact with the seat (22) of the poppet (23). The compression oil acts according to the area difference (d1-d2) between the cross-sectional area d1 and the cross-sectional area d2 of the rod portion (24) integrally formed with the poppet (23), and the compression spring (29).
The poppet (23) is opened by overcoming the resilience of the fluid and the pressure oil in the high pressure chamber (20) flows out to the low pressure chamber (21), and is formed in the poppet (23) and the rod portion (24). A pressure compensating spool (34) slidably provided on the inner diameter portion (45) of the piston (31), which has an oil chamber (39) communicating with the through hole (36) through an orifice (38), The compression spring (35) provided between the pressure compensation spool (34) and the closed end of the piston (31), the lateral hole (40) provided in the pressure compensation spool (34), and the piston (31). The piston back pressure chamber (43) provided at the inner diameter of the piston (31) at the other end
To the high pressure chamber (2) via a flow control valve with pressure compensation that forms a variable throttle with the groove (41) communicating with the oil passage (42) to
0) pressure oil from the through hole (36) to the orifice (3
8) and the variable throttle to introduce into the piston back pressure chamber (43) with a time delay, the operating pressure of the pressure regulating valve is gradually increased, and the piston (31) moves the stroke (G). In the pressure regulating valve configured so that the working pressure becomes constant at the moved position, the pressure regulating valve is installed in parallel with the pressure regulating compression spring (29), is initially in a free state, and is in the middle of the stroke (G) of the piston (31). Receiving the compression force of the piston (31), the pressure adjusting compression spring (2
The pressure regulating valve is characterized in that another compression spring (30) configured to exert an elastic force on the poppet (31) is provided together with 9).

[Operation] According to the pressure control valve of the present invention, in the pressure rising process, the pressing force of the pressure-adjusting compression spring first acts on the piston and the poppet, so that an extremely gentle pressure rise is performed, and the pressure is increased from the middle of the stroke. Since the pressing force of another compression spring is applied in addition to the pressure-adjusting compression spring, the pressure rising gradient is changed from the middle of the stroke, and the pressure is increased more rapidly.

[Embodiment] Hereinafter, an embodiment of the pressure regulating valve according to the present invention will be described in detail with reference to the accompanying drawings.

For convenience of explanation, the same members as those of the conventional structure shown in FIG. 4 are designated by the same reference numerals, detailed description thereof will be omitted, and only new members according to the present invention will be designated by new reference numerals. do.

In FIG. 1, a compression spring 30 is provided in parallel with the outer circumference of the compression spring 29 and is in a free state within a distance H smaller than the stroke G of the piston 31. The other components are the same as in the conventional example.

Next, the operation of the pressure regulating valve of the present invention having such a configuration will be described. In this case, the basic operation of the pressure regulating valve is the same as that of the conventional example and will be briefly described. That is, when the pressure in the high-pressure chamber 20 rises, the pressure oil acts on the poppet 23 with a pressing force corresponding to the area difference (d1-d2) between the oil passage 44 and the rod portion 24, and presses the pressing force of the compression spring 29. With the winning relief start operating pressure, the poppet 23 is pushed open to try to flow out from the high pressure chamber 20 to the low pressure chamber 21. At the same time, the pressure oil flows into the oil chamber 39 of the pressure compensating spool 34 through the through hole 36, but the orifice 38 provided at the inlet of the oil chamber 39 causes a time delay in the pressure increase in the oil chamber 39, This differential pressure overcomes the pressing force of the compression spring 35, moves the pressure compensating spool 34 to the right, and balances it at a balanced position as shown in FIG. Since a narrowed passage is formed, the amount of pressure oil flowing into the piston back pressure chamber 43 is small,
The pressure rise is further delayed as compared with the pressure rise in the high pressure chamber 20. Further, even if the piston 31 moves as the pressure in the piston back pressure chamber 43 increases and the pressing force of the compression spring 35 increases, the rightward direction of the pressure compensation spool 34 is returned so as to maintain the balance with the differential pressure. Therefore, the variable throttle opening between the lateral hole 40 and the groove 41 is maintained. Since the pressing force of the pressure oil in the piston back pressure chamber 43 acting on the piston 31 has a sufficiently large pressure receiving area, regardless of the increase in the elastic force of the compression spring 29 accompanying the movement of the piston 31, the flow rate adjusting valve with pressure compensation Defines the delay time to reach the set pressure of the pressure regulating valve. Since the inflow rate of the pressure oil into the piston back pressure chamber 43 is constant over time, the poppet 23 is set to the initial setting pressure of the compression spring 29, that is, the piston.
The operation starts when the right end of 31 comes into contact with the inner surface of the cap 33, and the pressure oil passes through the through hole 36 and the orifice 38 and side hole 4
0, as it flows into the piston back pressure chamber 43 through the variable throttle of the groove 41, the piston 31 overcomes the pressing force of the compression spring 29 and slowly moves to the left in the figure.

According to the present invention, when the piston 31 is moving to the left in this pressurization process, the compression spring 30 is initially in the free state and only the compression spring 29 is in contact with the piston 31, that is, the entire stroke of the piston 31. In G, the compression range of the compression spring 30 is in a free state. While the compression range of the compression spring 30 is H, the pressing force of the compression spring received by the poppet 23 is the compression spring.
Since it is only the pressing force of 29, the pressure gradient from the start of the operation of the pressure regulating valve depends only on the spring constant of the compression spring 29 and is relatively gentle at the portion h of the boost characteristic curve diagram shown in FIG. Has become.

Next, when the piston 31 finishes leftward stroke in the range H and comes into contact with the compression spring 30, the poppet 23 is compressed by the compression spring.
Since the combined pressing force of both 29 and 30 is received, the pressurizing gradient of the high pressure chamber 20 in this process is due to the sum of the spring constants of both the compression springs 29 and 30. It becomes the part of j, and it is changed to a steeper gradient than when only the compression spring 29 is used, and the piston 31 slides the entire stroke G in a short time,
The piston shoulder portion 32 stops at the position where it abuts the stopper portion 28 of the sleeve 26, and the pressure adjusting valve reaches the set pressure.

In this manner, in the pressure increasing process, the pressing force of the compression spring 29 acting on the piston and the poppet is applied with the pressing force of another compression spring 30 in addition to the compression spring 29 from the middle of the stroke, thereby increasing the pressure rising gradient of the stroke. It is possible to change it on the way.

[Advantage of the Invention] The pressure regulating valve of the present invention is driven at a relatively low pressure in the h range of the boosting process at the time of start-up, for example, at the time of start-up during turning of a mobile crane by providing such boosting characteristics. The revolving structure is activated very slowly, and after that, it can be operated faster, so it is possible to raise the pressure of a steeper slope, and at the beginning it can be activated extremely slowly and can be operated earlier from the middle, so Fine operation is possible, and very smooth operation is possible even when moving a large load.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the pressure regulating valve according to the present invention, FIG. 2 is a characteristic curve diagram showing the boosting characteristic of the pressure regulating valve of the present invention, and FIG. 3 is a swirl using the pressure regulating valve. Fig. 4 is a hydraulic circuit diagram of a construction machine having a body, Fig. 4 is a sectional view showing a conventional pressure regulating valve, and Fig. 5 is a detailed explanation of the "a" part of the pressure regulating valve of Fig. 4 in which the pressure compensating spool is right. It is a figure which shows the state which carried out and was balanced. 20 …… High pressure chamber, 21 …… Low pressure chamber, 22 …… Seat, 23 …… Poppet, 24 …… Rod part, 25 …… Housing, 26 …… Sleeve, 27 …… Inner diameter part, 28 …… Stopper part, 29,30,35 ...
… Compression spring, 31 …… Piston, 32 …… Piston shoulder, 33
...... Cap, 34 …… Pressure compensation spool, 36 …… Through hole, 37,39,46 …… Oil chamber, 38 …… Orifice, 40 …… Horizontal hole, 41 …… Groove, 42,44 …… Oil passage, 43 …… Piston back pressure chamber, 45 …… Inner diameter part.

Claims (1)

(57) [Scope of utility model registration request] 1. A poppet (23) for opening and closing between a high pressure chamber (20) and a low pressure chamber (21) at one end of a pressure regulating compression spring (29) of a pressure regulating valve, and the other end within a specified stroke (G). Cross-sectional area d1 abutting on one end surface of the piston (31) slidable with the seat (22) of the poppet (23) and a rod portion integrally formed with the poppet (23) The pressure oil according to the area difference (d1-d2) from the cross-sectional area d2 of (24) acts to overcome the resilience of the compression spring (29) and the poppet (2
3) Open the pressure oil in the high pressure chamber (20) to the low pressure chamber (21).
To the through hole (36) formed in the poppet (23) and the rod portion (24) while flowing out to the orifice (38).
The piston (31) having an oil chamber (39) communicating with the piston (31)
A pressure compensating spool (34) slidably provided on the inner diameter part (45) of the piston, and a compression spring (35) provided between the pressure compensating spool (34) and the closed end of the piston (31). , A lateral hole (40) provided in the pressure compensating spool (34) and an inner diameter of the piston (31) to communicate with an oil passage (42) to the piston back pressure chamber (43) at the other end of the piston (31) The pressure oil in the high pressure chamber (20) is passed from the through hole (36) through the orifice (38) and the variable throttle through the flow rate adjusting valve with pressure compensation that forms a variable throttle with the groove (41). By introducing the piston back pressure chamber (43) with a time delay, the working pressure of the pressure regulating valve is gradually increased, and the working pressure becomes constant at the position where the piston (31) moves through the stroke (G). A pressure regulating valve configured to be arranged in parallel with the pressure regulating compression spring (29). Is initially located in the free state, the piston (31) stroke (G) from said middle cooperate with said pressure regulating compression spring (29) under compressive force by the piston (31) the poppet (3
Another compression spring (3) configured to exert resilience on (1)
0) is provided, the pressure regulating valve.