JPS63246579A - Relief valve of hydraulic motor - Google Patents

Abstract

PURPOSE:To prevent a pressure shock at the time of starting by making the pressure oil acting area of a spring seat adapted to move by pressure oil on supply side smaller than the projection area of outer diameter of the spring seat. CONSTITUTION:A poppet 59 is inserted in an inner hole 58 of sleeve 53, and the trailing end of a rod 60 is slidably inserted in an inner hole of a spring seat 62. A spring 64 is disposed between the back of the poppet 59 and a spring seat 62. The acting area of the spring seat 62 to pressure oil, that is, the fitting portion area of the sprirng seat 62 to the sleeve 53 is made smaller than the diameter area of the spring 64. Accordingly, the set pressure of relief is increased so that peak at the time of starting relief can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a relief valve for a hydraulic motor used in an inertial drive circuit.

Generally, the inertial body drive circuit drives the inertial body by a hydraulic pump whose rotation direction and stop is controlled by a switching valve, and which is then guided by a hydraulic motor. However, when the switching valve is set to neutral while the hydraulic motor is rotating to stop the inertial body, the return side of the hydraulic motor is closed, causing a sudden increase in hydraulic pressure and an increase in energy, which causes shock and damages gears, etc. Sometimes I let it happen.

[Prior Art] For this reason, a relief valve shown in FIG. 5 has been conventionally installed in a hydraulic circuit to prevent a sudden increase in hydraulic pressure.

In the t55 diagram, 1 is a relief valve, and 2 is the valve body of the relief valve 1, which has a supply passage 3 and a return passage 4, and the passage 3
- Has a hole 5 that communicates with 4.

A sleeve 6 is fitted inside the circumference 5 in a liquid-tight manner.

This sleeve 6 has a stepped hole 7 formed therein having a large diameter portion 7a and a small diameter portion 7b.

A cap 8 screwed onto the opening side of the hole 5 of the valve body 2 has a hole 9 therein, and one side of the cap 8 is in contact with the sleeve 6, and the other side is closed with a plug 10.

Reference numeral 11 denotes a seat having a hole 11a and is attached to the valve body 2.

The outer bobbin (12) slidably inserted into the large diameter portion 7a of the stepped hole 7 has a hole 13 with one end open, and the other end surface having an eccentric hole 14 is in contact with the sheet 11, and its movement opens the supply passage. 3 is connected to the return passage 4. The inner poppet 15 inserted into the hole 13 of the outer poppet 12 has a hole 15a and a large diameter hole 15b connected thereto.

16 is a rod whose one side is inserted into the large diameter hole 15b of the plug 15 (with its other side inserted into the hole 18 of the spring seat 17), and its rightward movement is restricted by the end face of the plug 10 at the position shown in the figure. There is. Further, the axial passage 19 provided inside the rod 16 is connected to the supply passage 3 via the hole 15a and the eccentric hole 14 on one side, and has a horizontal hole 2o opening toward the outer circumference on the other side.

The spring seat 17 is sandwiched between the hole 9 of the cap 8 and the outer periphery of the rod 16 and is inserted so as to be movable in the axial direction. A passage 22 is provided that opens into a continuous spring storage chamber 24 on the outer periphery. Further, by moving the spring seat 17, the opening amount of the horizontal hole 20 is gradually reduced. The spring chamber 24 is formed by the spring seat 17, the cap 8, and the plug 1o. 25 is a spring that contacts the spring seat 17 on one side and the outer poppet 12 on the other side via a spring receiver 27 and a receiver 26.

28 is a spring chamber communicating with the tank T.

Next, the operation of this conventional example will be described. First, when the pressure in the supply passage 3 is low, the relief valve 1 is in an inoperative state, and the outer boppet 12 is pushed leftward by the spring 25 through the receiver 26 and the spring receiver 27 and comes into contact with the seat 11, and The seat 17 is in contact with the plug lO, and cuts off the supply passage 3 and the return passage 4 as shown in FIG.

Now, when the pressure of the hydraulic oil in the supply passage 3 increases, this pressure oil acts on the outer poppet 12, moves the outer poppet 12 to the right against the spring 25, and connects the supply passage 3 and the return passage 4 to provide relief. Begins action. On the other hand, the pressure oil is inserted into the eccentric hole 14 of the outer cylinder 12. It is introduced into the axial passage 19 through the hole 15a, roughly through the horizontal hole 20, an annular groove 21 and a passage 22, and into the spring storage chamber 24. The pressure oil in the spring chamber 24 moves the spring seat 17 leftward from the illustrated position against the spring 25 due to the pressure in the spring chamber 24 in response to the rise in pressure in the supply passage 3 . As a result, the spring 25 is further compressed, and the relief pressure increases. Due to this movement of the spring seat 17, the opening area of the horizontal hole 20 of the rod 16 gradually decreases, and the pressure oil to the spring chamber 24 is reduced. do. Furthermore, the spring seat 17 moves and the opening of the horizontal hole 20 is closed, and the spring storage chamber 2
Since the flow of pressure oil into the spring seat 4 is substantially eliminated, the right side position of the spring seat 17 is maintained. In this way, the increase in the set pressure becomes more gradual as it approaches the upper limit, so that the shock caused by the sudden pressure increase when the relief valve 1 is started can be alleviated. Further, when the pressure in the supply passage 3 becomes lower than the set value, the pressure in the spring chamber 24 becomes low, and the spring seat 17 returns to the illustrated position by the elastic force of the spring 25 in preparation for the next operation.

In the conventional example described above, when the pressure in the supply passage 3 increases, the outer boppet 12 first moves to the right against the spring 25, and at the same time, pressure oil flows into the spring storage chamber 24 on the right side of the spring seat 17. The spring seat 17 moves to the left while increasing the force (ie, relief pressure) of the spring 25.

As the spring seat 17 moves to the left, the area of the horizontal hole 20 through which the pressure oil passes becomes smaller and is eventually closed so that the relief pressure becomes the set pressure. As described above, the conventional method has the effect of reducing the pressure peak at the time of starting the relief valve. However, the area where the spring seat 17 acts on the pressure oil, that is, the area where the spring seat 17 fits into the cap 8 is as shown in FIG.
Even if the pressure is larger and lower than the diameter area of the spring 25, the spring seat 17
starts moving, and the horizontal hole 20 is connected to the spring seat 1 to read the required high pressure.
7, it was impossible to eliminate the large peak after closing the horizontal hole 20 and reduce the shock.

[Object of the invention] The present invention eliminates such drawbacks, and its object is to:
When the hydraulic pressure in the supply passage becomes high, the spring seat compresses the spring and increases the relief pressure by reducing the hydraulic action area of the spring seat.
To provide a relief valve for a hydraulic motor that reduces shock by eliminating pressure peaks at the time of starting the relief valve by preventing the relief valve from reaching a predetermined pressure at low pressures.

[Summary of the Invention] The relief valve for the hydraulic motor according to the present invention is a relief valve that moves the spring seat by introducing pressure oil on the supply side into the oil chamber of the spring seat, and this movement compresses the spring to adjust the relief pressure. The valve is characterized in that the pressure oil acting area of the spring seat is smaller than the projected area of the spring outer diameter.

[Embodiment of the Invention] Hereinafter, a description will be given of FIGS. 1 to 3 showing an embodiment of the present invention. In FIG. 1, pressure oil from a hydraulic pump 31 is controlled to be neutral, normal or reverse by a switching valve 32, and is sent to a hydraulic motor 33 to drive an inertial body 34. At the same time as the above-mentioned flow, the pressure oil of the hydraulic pump 31 is supplied to the tank 38 from the control valve 35 through the back pressure check valve 36 and filter 37 in parallel.
has been returned to. Pipeline 39 connected to hydraulic motor 33
and 40 are branched and connected to supply passages 42A and 42B of relief valves 4LA and 41B, and both pipelines 39 and 40
is connected by check valves 43A and 43B to become one, and in the middle is an outlet passage 44A of both relief valves 41A and 41B.
and 44B on the upstream side of the rear back pressure check valve 36 and the like. Note that the two members labeled A and B described above are the same.

Next, details of the above-mentioned relief valve 41A etc. will be explained with reference to FIG. A sleeve 53 is liquid-tightly screwed onto the valve body 51 by placing an O-ring 52 thereon, and its tip is located within the oil chamber 54 of the valve body 51 and is attached to the inner wall of the valve body 51 via a seat 55. A plug 57 is fixed to the pressed and inferior end via an O-ring 56. A poppet 59 is slidably inserted into the inner hole 58 of the sleeve 53.
The rear end of the rod 60 integrated with the poppet 59 is connected to the sleeve 5
The spring seat 62 is slidably inserted into the inner hole of the spring seat 62, which is slidably inserted into the inner hole 61 of No.3. A spring 64 is provided between the back surface of the poppet 59 and the spring seat 62 via a washer 63, so that the supply passage 42A-B (see FIG. 1)
When the pressure of the supply port 65 connected to the poppet 59 is low,
The tip of the valve is in contact with the valve seat of the seat 55. poppet 59
In the center of the rod 60 and the sheet 5 from the left side in the figure.
5 and a passage 66 that opens to the supply port 65 and a throttle 67.
and a passage 6 that opens into an oil chamber 68 which is the operating part of the spring seat 62.
9 are provided in series.

In addition, the valve body 51 has an outlet passage 44AΦB (see Fig. 1).
The lower output 0 connected to the inner hole 5 of the sleeve 53
8 and the oil chamber 54 are provided with horizontal holes 71 and 72 that communicate with the oil chamber 54.

Next, the operation of the embodiment described above will be explained. In FIG. 1, when the switching valve 32 is in the neutral state shown, the supply passage 42A-
B Therefore, there is no pressure at the supply port 65 (see FIG. 2), and the relief valves 41A and 41B are in an inoperative state. That is, the tip of the poppet 59 is pressed leftward by the spring 64 and is in contact with the seat 55, and the supply port 65 It is cut off from the output lower 0.

Next, when the switching valve 32 is switched from the neutral state to the upper position, pressure oil flows into the hydraulic motor 33 from the pipe line 39 and causes it to rotate normally. Even if the switching valve 32 is switched to the neutral position during this rotation, the hydraulic motor 33 does not stop immediately because of the inertia body 34, and the pressure in the pipe line 40 increases. Therefore, the pressure in the supply port 65 increases through the supply passage 42B, and this pressure acts on the poppet 59 to move it to the right against the spring 64, thereby moving the supply port 65 and the lower outlet o to the seat 55. The relief action is started by communicating with the side hole 71 through the horizontal hole 71.

At the same time, the pressure oil flows through the passages 66 and 6 of the poppet 59 and the rod 6o.
9 and is introduced into the oil chamber 68 through the throttle 67.
The pressure of the pressure oil 8 increases in response to the increase in pressure at the supply port 65, and moves the spring seat 62 to the left against the spring 64.

As a result, the spring 64 is further compressed and the relief pressure increases. The leftward movement of the spring seat 62 stops when the left side surface 77 of the flange part moves through the stroke until it comes into contact with the wall surface 78 of the valve body 51, and the relief pressure at this stop is the set pressure.

The oil thus relieved passes from the outlet lower 0 through the outlet passage 44B and the check valve 43A shown in FIG. 1, reaches the pipe line 39, and is supplied to the hydraulic motor 33.

Note that the flow of pressure oil into the oil chamber 68 is gradual due to the presence of the throttle 67 in the middle, and therefore the rise in relief pressure is also gradual, thereby alleviating the shock caused by a sudden pressure rise. Further, by increasing the stroke intersection, it is possible to increase the set pressure.

In Fig. 3, the lower part shows the operating position of the switching valve, and the upper part shows the relief pressure of the relief valve corresponding to this operating position.When the switching valve is switched from the operating position to the neutral position, the relief pressure increases. 4 is a diagram showing another embodiment of the present invention, in which the distance between the switching valve 32, the hydraulic motor 33, and the relief valve 41A@B is shown to rise in a gentle curve connected by circular arcs. The relief valves 41A and 41B, which are the subject matter of the present invention, are the same as those of the above-mentioned embodiments, except for the connection of the relief valves 41A and 41B, so a detailed description thereof will be omitted.

[Effects of the Invention] As explained above, in the relief valve of the hydraulic motor according to the present invention, the pressure oil acting area of the spring seat that compresses the spring and increases the relief pressure is smaller than the projected area of the outer diameter of the spring. Compared to the example, it was smaller, so the relief setting pressure was higher.

This has the advantage of sufficiently eliminating the peak at the start of relief and reducing shock.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention, Figure 1 is a mechanical diagram, Figure i2 is an enlarged view of the main part of Figure 1, and Figure 3 shows the operation position of the switching valve and the relief valve corresponding to this position. FIG. 4 is a diagram showing the relief pressure in another embodiment of the present invention, and FIG. 5 is a sectional view of a conventional example. 41A@41B...Relief valve, 62...Spring seat. 64...Spring, 68...Oil chamber.

Claims (1)

[Claims] In a relief valve that moves the spring seat by introducing pressure oil on the supply side into the oil chamber of the spring seat and compresses the spring by this movement to adjust the relief pressure, the pressure oil acting area of the spring seat is defined as the pressure oil acting area of the spring seat. A relief valve whose projected area is smaller than the seat outside diameter.