JP2538581Y2 - Inertia body swing back prevention valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a valve mainly applied to a hydraulic device of a construction machine such as a power shovel, in which an inertial body (that is, a heavy object, for example, a swing device including a shovel body) stops operating. The present invention relates to a device for preventing a return phenomenon that occurs at the time.

[0002]

2. Description of the Related Art When an inertial body is moved by using a fluid pressure actuator, it is needless to say that fluid is supplied to the actuator from a supply pipe connected to a pump or the like at the time of driving. It is common to use a relief valve or the like to generate a certain limit of braking pressure in the return line from the actuator.

However, just before the inertial body stops, a so-called swing back phenomenon occurs. That is, when the inertia body is almost stopped and the braking pressure becomes equal to or less than the set value of the relief valve, 1) the inertia body temporarily stops by closing the relief valve, but the supply side pipe is provided in the return side pipeline. Since the pressure energy corresponding to the pressure difference with the path exists, the actuator (and the inertial body) starts reversing operation due to the energy. 2) At this time, the pressure in the return line rapidly decreases. The actuator is over-reversed by the pressure energy in the side line (that is, the pressure energy on the return side is replaced by the pressure energy on the supply side through the kinetic energy of the inertial body), so that the supply is performed in reverse. The pressure in the side line increases, and 3) the actuator further reverses based on the pressure energy on the supply side. A.

[0004] An apparatus which can prevent the above-mentioned swing back phenomenon while being a hydraulic apparatus for moving an inertial body has already been described in Japanese Patent Publication No. 2-58481. The device disclosed in the publication has a circuit configuration shown in FIG.
The hydraulic oil is supplied to the pipeline 3A or 3B by operating the direction control valve 8b (and the counter balance valve 8c that switches at the same time) from the hydraulic oil supply source 8 having an inertia body (not shown) together with the hydraulic motor 2. ) In the desired orientation. On the other hand, by setting the valve 8b (and the valve 8c) to the neutral position, a braking pressure is generated in the return line 3B or 3A by the action of the relief valve 4B or 4A to stop the motor 2.

A feature of the apparatus shown in FIG. 3A is that the apparatus is provided with an anti-swinging valve 101 shown in FIG. 3B. The valve 101 is configured as follows. Referring to the drawings, the valve 101 is configured such that a plunger 120, a piston 130, a seat member 140, a spring 150, a spring 160, and the like are arranged along an axis inside a casing 110 having a plug 111 attached to an end of a cylindrical portion. It is incorporated so as to be movable. The plunger 120 has a cylinder hole 121 and a small hole 122 connected to each other and penetrates the inside thereof.
0 is slidably fitted. The sheet member 140 also has a penetrated inner hole 142. When the circumferential sheet surface 141 is in close contact with the shaft end of the plunger 120 on the side of the small hole 122, the inner hole 142 is formed in the small hole 1.
22 (and the cylinder hole 121). The spring 150 attached between the plunger 120 and the casing 110 and the spring 160 between the seat member 140 and the casing 110 are attached so as to push the plunger 120 and the seat member 140 to the left in the drawing, that is, toward the plug 111. Have been. The casing 110 containing these components includes a first port A ′ communicating with a shaft end on the right side (opposite to the plunger) of the seat member 140 and an inner hole 142 thereof, and a second port B ′ communicating with the outside of the seat surface 141. In addition to having
The liquid chamber 115 is formed between the sheet chamber 140 and the sheet member 140. The liquid chamber 115 is provided in the orifice hole 11.
6 to the first port A '.

The opening and closing of the swing-back preventing valve 101 is performed as follows. First, when the pressure applied to the first port A ′ is high, the cylinder hole 12
The force acting in the rightward direction (toward the sheet member 140) in the figure based on the cross-sectional area difference between the sheet member 141 and the sheet surface 141 is large. The state between B 'is closed. When the pressure of the first port A ′ is low, the spring 160 moves the plunger 120 toward the plug 111 by the force of the spring 150 or the like.
Since the sheet member 140 is pressed by such force, the space between the ports A ′ and B ′ on the seat surface 141 is also closed. However, the first port A 'which was expensive until then
When the pressure of the plunger 12 suddenly decreases, the plunger 12
0. The sheet member 140 is separated to open the space between the ports A ′ and B ′. Because, in this case, the spring 15
This is because the movement of the sheet member 140 in the same direction is delayed due to the damping action of the liquid chamber 115 having the orifice hole 116 with respect to the plunger 120 that quickly moves to the plug 111 side by a force such as zero.

The apparatus shown in FIG. 3A in which two such valves 101 are provided with pipes 3A and 3B before and after the motor 2 being connected in the opposite direction of the first port A 'and the second port B'. The swing back phenomenon of the motor 2 and the inertial body is effectively suppressed. As described above, this phenomenon is caused by the fact that the pressure energy increases alternately in the pipelines 3A and 3B before and after the motor 2 (supply side and return side). When the pressure of 'is going to decrease, ports A' and B ', that is, two pipes 3A
-It is because the pressure energy is released quickly by connecting the 3Bs. For example, when the motor 2 is stopped by generating a braking pressure in the pipeline 3A, when the brake pressure approaches the stop and the braking pressure becomes equal to or less than the set value of the relief valve 4A, the valve 4A is first closed and the motor 2 stops once. Immediately after that, the motor 2 starts reversing operation due to the pressure energy in the pipe 3A, and the pressure in the pipe 3A is about to drop sharply. At this time, the valve 101 communicates between the pipes 3A and 3B. The pressure difference between the two approaches zero by sending hydraulic oil from the former side to the latter. Eliminating the pressure difference between the two conduits 3A and 3B means that there is no pressure energy for reversing (ie, swinging back) the motor 2.

For further details on the structure and function of the hydraulic device and the valve 101 shown in FIG. 3, refer to the above-mentioned publication.

[0009]

In many cases, the direction in which the hydraulic actuator drives the inertial body is bidirectional, that is, two directions, forward and reverse. This is true whether the actuator is, for example, a hydraulic motor or a hydraulic cylinder, and is generally applicable to not only construction machines but also various machines.

However, the anti-sway-back valve 10 shown in FIG.
1 functions to open between the ports A 'and B' only when the pressure at the first port A 'drops sharply. Fig. 3 (a)
As described above, two pipes must be installed in different directions between the pipes before and after the motor 2.

If two anti-sway valves are required in one device, the cost of the device is naturally high and the maintenance burden is increased accordingly. In some cases, it may be difficult to secure an installation space for the valve in the apparatus.

An object of the present invention is to provide a swing back which functions effectively in both directions of the bidirectional movement of the inertial body and the hydraulic actuator only by installing one between the front and rear pipes of the hydraulic actuator. It is to provide a check valve.

[0013]

According to the present invention, the conventional valve for preventing the inertial body from swaying back (see FIG. 3 (b)).
In addition to the configuration described above, the closed space between the axial end of the plunger including the piston and the end of the casing is communicated with the second port, and the piston diameter d ₁ and the seat surface diameter d
₂ was assumed to satisfy the relationship d ₂ = d ₁ / √2 (i.e. ^{_{d 2 2 = d 1 2/}} 2) for.

[0014]

The operation of the anti-sway valve of the present invention when pressure is applied from the first port side is not particularly different from that of the conventional valve shown in FIG. 3 (b). Applies similarly. The space between the first and second ports is normally kept closed by the close contact of the seat surface, and is opened only when the pressure (braking pressure) of the first port suddenly drops from a high pressure.

The feature of the anti-sway valve of the present invention is that the same effect as described above is obtained for the pressure (braking pressure) from the second port. That is, since the closed space between the shaft end of the plunger including the piston and the end of the casing communicates with the second port, when the pressure applied to the second port is high, the plunger is strongly seated by the plunger. To close the seat surface, so that the first and second ports are closed.

When the pressure of the second port is low,
The plunger is pushed toward the end of the casing (the side with the piston) by the force of the spring, and the seat member is also pressed against the shaft end of the small hole side of the plunger by the force of the spring, so that the seat surface is in close contact. The first and second ports are closed.

However, if the pressure of the second port, which had been high until then, suddenly drops, the damping action of the liquid chamber having the orifice hole against the plunger that moves quickly toward the end of the casing by the force of a spring or the like. Since the movement of the sheet member in the same direction is delayed by the time, the plunger and the sheet member are separated from each other on the sheet surface to open the space between the first and first ports and move to the second port before moving from the above state. Fluid flows from the side to the first port side.

Moreover, as described above, the situation where the first and second ports are open (that is, the sheet surface is separated) (how to open).
Is the same as that described above when both ports are open. This means that the pressure at the second port (which is p _sb ) when is equal to the pressure at the first port (which is p _sa ), and in both cases both ports This means that the intervals are equal, and the reason is explained as follows.

The balance of the force applied to the plunger at the moment when the high pressure applied to the first port suddenly drops and the plunger tries to separate from the seat member (that is, the above-mentioned state) is obtained. place from the side of the shaft end portion of the sheet side force directed towards the shaft end portion of the cylinder bore side to the left ^{_{side, πd 2 2 · p sa /}} 4 + F = πd 1 when placed in the right side of the force in the opposite direction ² · p _sa / 4 (F is the magnitude of the force of the spring applied to the plunger at the position of.) On the other hand, the pressure of the second port suddenly drops and the plunger separates from the seat member.
Balance moment of the plunger from taking analogously left-right ^{_{F = πd 2 2 · p sb}} / 4 and d ₂ = d ₁ / √2 or more Type 3 according to the present invention, the p _sb = p _sa It is understood that details such as the process of deriving the formula are described in the section of Examples.

The time during which the first and second ports are open is the time required for the sheet member to catch up with the plunger that has moved earlier. It depends on how fast you get out. Factors related to the speed, such as fluid properties (viscosity, etc.), the size of the orifice hole, the force of the spring pressing the sheet member, and the pressure difference between the inside and outside of the orifice, are such that the pressure acts on the first port side. There is no difference between the case where the state becomes the state described above and the case where the state acts on the second port side. Therefore, in this case, it is the same as the case where the time between both ports is open.

Therefore, if one valve of the present invention is installed by connecting the first and second ports respectively to the front and rear pipes of the fluid pressure type actuator (the reverse connection is also possible), the same effect can be obtained. The swingback at the time of stoppage is effectively prevented equally for the bidirectional operation of the actuator and the inertial body.

[0022]

1 is a longitudinal sectional view of an anti-sway valve 1 according to an embodiment of the present invention. FIG. 2 shows a hydraulic circuit using the valve 1 of FIG. 1 for turning a construction machine (power shovel). 2 (lines 3A and 3
B) includes a hydraulic oil supply source 8 shown in FIG.
The same supply source (not shown) is connected. The turning portion of the machine, which is an inertial body, is driven in either direction by the hydraulic motor 2 of FIG. 2 capable of bidirectional rotation, and thereafter, the relief valve 4A or 4B (and the check valve 5A).
Or 5B), when the brake pressure is generated to stop the motor, the turning portion and the motor 2 tend to swing back just before the stop (as described above). Is the role of this valve 1.

The structure of the valve 1 is shown in FIG.
There is not much difference from the swing back prevention valve 101 shown in FIG. That is, the plunger 20, the piston 30, the seat member 40, the spring 50, the spring 60, and the like are incorporated inside the casing 10 along the axis. The description for each part is as follows.

Plunger 20: A cylinder hole 21 having an opening at one shaft end 23 (upper side in the figure), and a small hole 2 having an opening at the other shaft end 24 following the cylinder hole 21.
And 2. Each side surface near the shaft ends 23 and 24 is slidably held by the inner peripheral surface of the cylindrical portion of the casing 10. In order to later description, placing the latter sliding portion of the diameter (outer diameter of shaft end 24) and d _3.

A piston 30 is a pin-shaped part which is slidably inserted into a cylinder hole 21 of the plunger 20 so as to be able to slide in and out of a shaft end 23 thereof. And the overall length is slightly longer than the depth of the cylinder hole 21. The diameter of the piston 30 (approximately equal to the inner diameter of the cylinder bore 21) is set to d _1.

The seat member 40 is disposed below the plunger 20 in the figure so that the circumferential portion can be in close contact with the shaft end 24 on the side of the small hole 22 of the plunger 20 as the seat surface 41. Has an inner hole 42 over the entire length from the inside. The side surfaces of the portion close to the seat surface 41 and the brim portion 43 near the shaft end on the side opposite to the plunger (far side from the seat surface 41) are slidably held by the inner peripheral surface of the casing 10, respectively. . Seat surface 4
The diameter of 1 is d ₂ .

The spring 50 pushes the plunger 20 in the direction of the shaft end 23 on the cylinder hole 21 side, and is compressed and incorporated between the plunger 20 and the casing 10.

Spring 60: The brim portion 4 of the sheet member 40 is pressed so as to push the sheet member 40 toward the plunger 20.
It is compressed and incorporated between the casing 3 and the casing 10. The spring force of this is weaker than the spring 50.

The casing 10 has a cylindrical portion formed so as to slidably hold the plunger 20 and the sheet member 40 in the axial direction, and the end (the upper end in the figure) is sealed with the plug 11. The end 31 of the piston 30 contacts the plug 11. On the side opposite to the plug 11 (lower end in the figure), a first port A communicating with the shaft end of the seat member 40 on the side opposite to the plunger and the inner hole 42 is provided. A second port B is provided which communicates with an outer portion of the seat surface 41 and a mounting portion of the spring 50 through the second port B. Further, in the portion of the casing 10 that slidably holds the sheet member 40,
The liquid chamber 15 in which the hydraulic oil is sealed is provided between the flange 43. However, this liquid chamber 15 is
Through the orifice hole 16 on the side of the first port A.

The characteristic of this valve 1 is that, as shown in FIG. 2, only one hydraulic motor 2 that rotates in two directions is provided in the drive circuit thereof. Is to be able to prevent the swing back. The following two points can be said to be configurations for that purpose.

The first point is that, as shown in FIG.
A notch in the axial direction is formed in a part of a side surface (a part that slides with the casing 10) near the shaft end 23 of the zero to form a communication passage 25 for hydraulic oil. By forming the communication passage 25, a closed space formed between the shaft end 23 of the plunger 20 including (the end 31 of) the piston 30 and the plug 11 of the casing 10 is formed in the second port B. Will be communicated.

[0032] The second is that it has to satisfy the relation _{d 2 = d 1 / √2 ‥‥} (1) for the said diameter d ₂ of the diameter d ₁ and the sheet member 40 of the piston 30.

The anti-sway-back valve 1 having such a configuration is as follows.
For example, as shown in FIG. 2, when the first port A is connected to the pipe 3A and the second port B is connected to the other pipe 3B, the following functions are performed.

When the pressure of the pipe 3A applied to the first port A is high: Referring to FIG. 1, the plunger 20 is directed downward (sheet member) based on the cross-sectional area difference between the cylinder hole 21 and the seat surface 41. 40), the pressure from the second port B side and the spring 50
Is larger than the reverse force including the force of (1), the plunger 20 is pressed in the direction of the seat member 40. Since the force of the spring 60 acts on the seat member 40, that is, the seat surface 41 is in close contact, and the state between the ports A and B is closed.

When the pressure of the conduit 3A applied to the first port A is low: The plunger 20 moves toward the plug 11 by a force including the force of the spring 50 and the pressure from the second port B side, and the seat member is 40 is the spring 6
Since it is pressed by the force of 0, the space between the ports A and B on the seat surface 41 is also closed.

When the pressure at the first port A suddenly drops from the above state: In this case,
In the circuit of FIG. 2, a braking pressure corresponding to the set value of the relief valve 4A is generated in the pipeline 3A to brake the hydraulic motor 2,
This corresponds to the case where the motor 2 starts to reverse (swing back) due to the pressure energy in the conduit 3A immediately after the relief valve 4A is closed. In this case, in the valve 1, the movement of the seat member 40 is delayed by the damping action of the liquid chamber 15 having the orifice hole 16 with respect to the plunger 20 which moves promptly to the plug 11 side by the force of the spring 50. , The plunger 20 and the sheet member 40 are separated, and the space between the ports A and B is opened. Therefore, the hydraulic oil in the pipe 3A flows through the valve 1 into the pipe 3B,
The pressure energy that causes the reversal disappears in a short time.

The balance of the force applied to the plunger 20 at the moment when the seat surface 41 is about to open as the pressure of the first port A has decreased from the above state is from the shaft end 24 near the seat member 40. place the force (upward in the figure) of the directed towards the cylinder bore 21 of the shaft end portion 23 to the left ^{_{side, πd 2 2 · p sa /}} 4 + F = πd 1 2 · placing the right forces in the opposite direction p _sa / 4 ２ (2) (where p _sa is the pressure at the first port A at the moment when the seat surface 41 is opened. F is the force of the spring 50 applied to the plunger 20 at that moment, that is, the still position. ) and expressed, which from ^{_{F = π (d 1 2 -d}} 2 2) · p sa / 4 ‥‥ (2 ') is derived.

When the pressure of the pipe 3 B applied to the second port B is high (inverse to the above): The pressure of the second port B is increased through the passage 34 and the communication passage 25 to the end 3 of the piston 30.
1 and the shaft end 23 of the plunger 20, the spring 50 including the pressure from the first port A side.
The plunger 20 is pressed in the direction of the seat member 40 by receiving a strong downward force exceeding the above force. In addition, since the force of the spring 60 acts on the seat member 40, the seat surface 41 is in close contact with the seat member 40, and the space between the ports A and B is closed.

When the pressure of the pipe 3B applied to the second port B is low: The plunger 20 moves toward the plug 11 by the force including the force of the spring 50 and the pressure from the first port A side, and the seat member 40 is the spring 6
Since it is pressed by the force of 0, the space between the ports A and B on the seat surface 41 is also closed.

When the pressure at the second port B suddenly drops from the above state: In this case,
In FIG. 2, contrary to the above, a braking pressure corresponding to the set value of the relief valve 4B is generated in the pipeline 3B to brake the hydraulic motor 2, and soon after the relief valve 4B is closed, the pipeline 3
This corresponds to the case where the motor 2 starts to reverse (swing back) due to the pressure energy in B. In the valve 1, the movement of the seat member 40 is delayed with respect to the plunger 20, which quickly moves to the plug 11 side. Opens. This time when the ports A and B are open is not different from the time in the above case.
The time is the time until the sheet member 40 catches up with the plunger 20 that has moved earlier, and the liquid chamber 1
5 is determined by the speed at which the hydraulic oil flows out of the orifice hole 16, but the same hydraulic oil passes through the same orifice hole 16 under the same condition that there is no difference between the pressures inside and outside the same hole 16. It flows out under the force of 60, so it coincides with the natural time. During this time, the hydraulic oil in the pipe 3B flows through the valve 1 into the pipe 3A, so that the pressure energy that causes the inversion is lost.

In the same manner as described above, the plunger 20 at the moment when the seat surface 41 is about to open as shown in FIG.
(The force from the shaft end 24 toward the shaft end 23 is placed on the left side, and the force in the opposite direction is placed on the right side), and π (d ₃ ² −d ₂ ² ) P _sb / 4 + F = πd ₃ ² p _sb / 4 ‥‥ (3) (where p _sb is the pressure of the second port B at the moment when the seat surface 41 opens. F is the moment, that is, a force of the spring 50 according to the plunger 20 in the position represented with the same size) and F of the formula (1) above, which from ^{_{F = πd 2 2 · p sb}} / 4 ‥‥ (3 ' ) Is derived.

[0042] Formula (2 ') - (3') turn off the F from the ^{_{πd 2 2 · p sb / 4}} = π (d 1 2 -d 2 2) · p sa / 4 ∴ p sb = p sa × ( d ₁ ² −d ₂ ² ) / d ₂ ^{2. In} this valve 1, the above equation (1) is satisfied.
d ₂ ² = p are substituted into the above equation ^{_{d 1 2/2 sb = p}} sa i.e., the pressure of the second port B of the moment the seat surface 41 is opened by the first port of the layers of the moment by A
Pressure. This means that in the circuit of FIG. 2, the pressure condition under which the valve 1 starts to open after applying the braking pressure to the pipe line 3B side, the motor 2 rotates in the opposite direction,
This means that the valve 1 starts to open after the braking pressure is applied to the pipe 3A side at the time of stoppage, which means that the pressure condition matches.

As described above, at ports A and B
Since the interval is the same, the function of the valve 1 for preventing the motor 2 (and the inertial body as a load thereof) from swinging back is exerted in the same manner in any rotational direction of the motor 2. Will be.

Although one embodiment has been described above, the anti-sway valve according to the present invention can be implemented as follows.
That is, a) it is easy to stabilize the axial movement of each part by holding the plunger and the seat member slidably on each of the plurality of side surfaces by the casing, but this is not essential. So, for example,
In FIG. 1, a part of the casing 10 holding a side surface (portion having a diameter d ₃ ) near the shaft end 24 of the plunger 20 may be cut off as indicated by a virtual line x. Cutting this portion facilitates the formation of the passage 34. In this case, the above equation (3) is somewhat inappropriate, but instead, equation (3 ′) is directly derived.

(B) Needless to say, the valve of the present invention can be used in circuits other than that shown in FIG. For example, the relief valve can be used in the circuit shown in FIG. 3A in which the connection method is different (of course, the original two valves 101 are removed and one valve of the present invention is connected). It can also be used for other circuits using a cylinder or the like as an actuator.

(C) Even if the actuator is operated only in one direction, there is no problem. Since the valve of the present invention does not include a portion with manufacturing difficulty compared to the conventional valve (see FIG. 3B), there is no cost disadvantage in that case.

D) Although the plunger and the piston / sheet member have all been described as having a circular cross section, in principle, they need not be circular. This is because when the cross section is rectangular or hexagonal (although it is not advantageous in terms of production), the same operation and effect as in the case of a circular shape are obtained. In such a case, however, the diameter of each part described in the claims may be replaced with an appropriate cross-sectional dimension (side length or side-to-side dimension, etc.), or their relational expression may be replaced with a relational expression between cross-sectional areas as necessary. Should.

[0048]

[Effect of the Invention] The anti-sway valve of the present invention is only installed between the front and rear pipes of the fluid pressure type actuator.
Regardless of whether the actuator or the inertial body is operated in the forward or reverse direction, the actuator and the inertial body are prevented from swinging back when stopped. Compared to the conventional anti-sway valve, which is required before and after the actuator, there are no parts that are difficult to manufacture and there is no increase in size, so there is a significant advantage in terms of cost, installation space, and maintenance. It is.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an anti-sway valve 1 according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing an example of an apparatus using the valve 1 of FIG.

FIG. 3 (a) is a hydraulic circuit diagram of a device using a conventional anti-sway valve, and FIG. 3 (b) is a longitudinal sectional view showing the conventional anti-sway valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Casing 11 Plug (end part) 15 Liquid chamber 16 Orifice hole A 1st port B 2nd port 20 Plunger 21 Cylinder hole 22 Small hole 25 Communication passage 30 Piston 40 Seat member 41 Seat surface 42 Inner hole 50/60 Spring

Claims (1)

(57) [Scope of request for utility model registration] To prevent the inertial body, which is the load of the hydraulic actuator, from swinging back when stopped, a) a cylinder hole having an opening at one shaft end, and the other shaft following the cylinder hole. a plunger having a small hole having an opening at an end portion, b) to the cylinder bore of the plunger, the shaft end portion and out freely fitted encased diameter d ₁ of the piston from, c) a plunger of the small by the sliding with circumferential portion of diameter d ₂ on the shaft end portion of the hole side can closely as the sheet surface, the sheet member, d) a plunger to the cylinder bore side having along the entire length of the bore leading to the small holes from the inside of the seat surface A) a spring that pushes the seat member toward the plunger, and a) a cylindrical portion where the plunger and the seat member slide in the axial direction, and an end where the piston abuts. B) a first port communicating with the shaft end of the seat member on the side opposite to the plunger and its inner hole, and a second port communicating with the outside of the seat surface, and c) a first port through the orifice hole. A valve configured to be incorporated in a casing provided with a liquid chamber communicating with a port between the seat member and a closed space between a shaft end of the plunger including a piston and the end of the casing. An anti-sway-back valve for an inertial body, characterized in that the valve communicates with two ports and satisfies the relationship d ₂ = d ₁ / √2 for the diameters d ₁ and d ₂ .