JP2555919Y2 - Inertial body control device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inertial body control device. More specifically, the present invention relates to a control device at the time of turning deceleration of a construction machine.

[0002]

2. Description of the Related Art A conventional example will be described with reference to FIGS. In the conventional inertial body control device, a pair of relief valves 6 connected to main pipelines 7 and 8 on both sides of the hydraulic motor are provided between the directional control valve 2 and the hydraulic motor 4 as shown in FIG. doing.

In FIG. 6, when the operation lever of the remote control valve 3 is operated in the direction of arrow A, the direction control valve 2 is switched to the left (B) position, and the hydraulic motor 4 is connected to the hydraulic pump from the main line 7. The inertial body 5 is accelerated and driven in one direction by the discharge flow rate of 1.

When the inertial body 5 reaches a steady speed, the main pipeline 7
The pressure P ₁ is pressure as shown in FIG. 7 motor - motor 4 is reduced to the pressure required to maintain a given rotation speed.

When the operation lever of the remote control valve 3 is returned to the neutral position (the position shown in FIG. 6) in order to stop the inertial body 5, the direction control valve 2 is also switched to the neutral position, and the main pipelines 7, 8 are provided.
Is passed through. Therefore the pressure P ₂ of the main channel 8 spikes, Lili - is controlled by the key pressure, - shake off valve 6
The shock when the operation lever is returned to the neutral position is large (see reference numeral (a) in FIG. 7).

Therefore, even if the operation lever is gradually returned to the neutral position in order to stop the operation with little shock, the inertia body 5 tends to rotate by the inertial force, so that the same brake pressure as described above is generated. (Refer to the symbol (b) in FIG. 7).

After being controlled by opening the relief valve 6 as described above, when the relief valve 6 closes, the operation temporarily stops.
Since the pressure P ₂ of the brake-side main channel 8 of the high pressure, the hydraulic motor - motor 4
Starts reversing due to the pressure difference before and after. Thus differential pressure becomes zero decreases rapidly, hydraulic motor - motor 4 for rotating too as the position where differential pressure due to the inertia force of the load is zero, this time the pressure P ₁ of the main conduit 7 , And the pressure difference before and after the motor increases, whereby the hydraulic motor 4 reverses again and passes the stop position again, thus repeating reversal in this way.

In order to prevent this reversal, the reversal prevention valve 9 is provided so as to be connected to the main pipelines 7, 8 as shown in FIG.

This is because when the pressure P _{1 in the} main line 7 increases, the check valve 9 is moved to the position shown in FIG.
Switching the position of the (c), a main conduit 7, 8 connect momentarily, the pressure P ₁ and P ₂ to the same pressure, the hydraulic by confinement pressure mode - data 4
In order to prevent the reversal.

[0010] With the configurations shown in the above two examples, (1) when returning the operating lever to the neutral position, the brake pressure rises sharply regardless of the operating method, so Occurs, giving the operator discomfort.
(2) Even in the inertial body control device in which the reversal prevention valve 9 is provided, as shown in FIG.
_{Since the} reversal prevention valve 9 operates at ₁ , complete reversion prevention was not possible. This has an adverse effect on the operability when the turning is stopped.

[0011]

SUMMARY OF THE INVENTION In view of the problems of the prior art, it is an object of the present invention to reduce the shock at the time of turning deceleration and to prevent reversal at the time of turning stop to further improve operability.

[0012]

Means for Solving the Problems Both ports of the hydraulic motor 4
A pair of variable relief valves 16L and 16R, which are provided between the main lines 7 and 8 connected to the main ports 7 and 8 and whose operating pressure increases to reduce the variable relief valve pressure; ₁
And Setsu換Ru 3-position switching valve 12 to the A position and the C positions of the left and right from the neutral position B by the pressure of the greater of P _2, the pressure P ₁ of the provided between the main conduit 7, 8 main line 7,8 made from the shuttle valve 13 which through a pressure greater of P _2, the three-position switching valve 12 is the pair of variable Lili - off valve 16L
And a port connected to the shuttle valve 13 connected between the oil passages 14 and 15 and the main pipelines 7 and 8 and a three-position switching valve. In the neutral position B of 12, almost zero pressure of the main lines 7 and 8 is supplied from the shuttle valve 13 to the pair of variable relief valves 16L and 16R.
The through, also the main conduit 7 operating pressure variable Lili through the oil passage 15 from the remote control valve 3 is at position A was Tsu switchable pressure P ₁ of the - and off valve 16L, and the pressure P ₁ of the main conduit 7 a shuttle valve 1
Variable Lili through 3 - as communicating with off valve 16R, further variable releases via the pressure P ₂ is the shuttle valve 13 of the main channel 8 in C positions Tsu switchable pressure P ₂ of the main channel 8 - off valve 16L
Also, the operating pressure from the remote control valve 3 is connected to the variable relief valve 16R through the oil passage 14, so that the set pressure of the pair of variable relief valves 16L and 16R corresponds to the operation amount when decelerating. It is possible to control the pressure to the relief pressure and to the low pressure at the time of stop.

A pair of variable relief valves are provided between the main lines 7 and 8 connected to both ports of the hydraulic motor 4, and when the operating pressure increases, the variable relief valve pressure decreases. 16
L, 16R and the pressure P ₁ and Setsu換Ru 3-position switching valve 12 from the neutral position B by the larger pressure of P ₂ to the A position and the C positions of the left and right main lines 7,8, the remote control valve 3 A three-position switching valve 17 for switching from the neutral position B to the left and right positions A and C by an operating pressure communicating with the operating pressure oil passages 14 and 15, and the three-position switching valve 12 is a pair of variable relief valves 1
Ports connected to 6L and 16R, and two remote control valves
A port communicating with one of the operating pressure oil passages 14 and 15 and a port communicating with another three-position switching valve 17. The three-position switching valve 17 is connected to the port connected to the switching valve 12. A pilot pump and a port communicating with the tank are provided. At the neutral position B of the three-position switching valve 17, a neutral position B communicating with the pair of relief valves 16L and 16R of the three-position switching valve 12 and the pilot pump are connected. At the left and right positions A and C which are connected via the oil passage 18 and switched by the switching pressure from the remote control valve 3, the connection with the pilot pump is cut off and the three-position switching valve 12 is disconnected.
The set pressure of the pair of variable relief valves 16L and 16R is reduced to a relief pressure corresponding to the manipulated variable when decelerating, and is set to a low pressure relief when stopped. The pressure can be controlled.

[0014]

First Embodiment A description will be given based on FIG. The same components as those of the conventional example shown in FIG. A pair of variable relief valves 16 (16L, 16R) are disposed between the main lines 7 and 8 on both sides of the hydraulic motor 4. Further, a three-position switching valve 12 is provided between the main lines 7 and 8 so as to be switched in each direction by the pressures P ₁ and P ₂ of the main lines 7 and 8. The switching valve 12 has three positions (A), (B) and (C). In the neutral position (B), the main line 7 or 8 and the shuttle valve 13 are provided.
Through a pair of variable relief valves. Shuttle valve 13 is connected to main lines 7 and 8.

When the switching valve 12 operates at the pressure P ₁ of the main line 7,
When the position is switched to the position (A), the oil passage 15 from the remote control valve 3 is connected to the variable relief valve 16L and the shuttle valve 13 to the variable relief valve 16R. Further switching valve 12 is switched to the position (C) at a pressure P ₂ of the main channel 8, the oil passage 14 is variable Lili from the remote control valve 3 - off valve 16R and also the shuttle valve 13 and the variable releases - and off valve 16L Connected. As shown in FIG. 2, the pair of variable relief valves 16L and 16R are set so that when the operating pressure is small, the variable relief valve pressure is large, and when the operating pressure is large, the variable relief valve pressure is reduced. Have been.

[0016]

[Operation] The operation is as described above, and the operation is as follows. 1) When neutral; switching valve 1 because P ₁ = P ₂ (almost zero pressure)
2 is in the neutral position (B), so that the variable relief valve 16 (1
6L, 16R) are both operated at a low pressure, and are therefore set at a high pressure (see FIG. 2). 2) Slope holding at neutral; P ₁ > P ₂ , switching valve 12
Is in the A position, and the larger pressure P ₁ is
Variable Lili through the switching valve 12 from - but is led to off valve 16, this time the switching valve 12 at a pressure P ₁ is (A) Setsu換Ru for the position, the variable Lili - large pressure P ₁ on off valve 16R side effects 2, the variable relief valve 16 having a low operating pressure is used.
L is set to a high pressure, and similarly, the variable relief valve 16R is set to a low pressure. 3) acceleration, steady speed (remote control valve 3 of the operation lever - operate in the direction of arrow A in FIG. 1); P _1> for P _2, 2 above)
Similarly, the variable relief valve 16L is set at a high pressure and the variable relief valve 16R is set at a low pressure. 4) deceleration (Operation of the remote control valve 3 lever - when returning to suddenly neutral and reference symbol a in FIG. 3); although deceleration becomes P _2> P ₁ from _{P 1> P 2 dp 2 /} dt ( Pressure gradient)
Switching valve 12 (A) (C) Setsu換Ri the position from the position, the variable Lili acts of greater operating pressure P ₂ - off valve 16L to the low-voltage, variable acting pressure of the oil passage 14 connected to the remote control valve 3 The relief valve 16R is set to a high pressure.

[0017] 5) Stop the time; P ₂ is but lowered P ₁ is increased,
Since the pressure gradient dp ₁ / dt (dp ₂ / dt) is relatively gentle, when P ₁ = P ₂ , the switching valve 12 changes from the (C) position to the neutral (B) position. At this time, the pressure (P ₁ = P ₂ ≧ operating pressure) introduced from the shuttle valve 13 acts on the variable relief valve, and the pair of variable relief valves 16L and 16R are both set to low pressure. For this reason, the pressures P ₁ and P ₂ of the main pipelines 7 and 8 rapidly become the same pressure, thereby preventing reversal.

6) Inching deceleration (when the operation lever is gradually returned to the neutral state, see reference numeral b in FIG. 4); P ₁ > P ₂ to P ₂
> Although the P _1, since the pressure gradient dp ₂ / dt is steep, the switching valve 12 is (A) position from the position (C). Remote control valve 3
The pressure from the valve acts on the variable relief valve 16R through the oil passage 14, and the relief set pressure (brake pressure) corresponding to the operation amount is obtained from the relationship between the operation pressure and the variable relief valve pressure shown in FIG. As a result, shock is reduced and operability is improved.
The variable relief valve 16L is a high pressure set.

[0019]

Second Embodiment A description will be given based on FIG. In this embodiment, instead of the shuttle valve 13 in the first embodiment of FIG.
A three-position switching valve 17 that switches according to the operation pressure from the remote control valve 3 is provided. The three-position switching valve 17 has three positions (a), (b) and (c). In the neutral position (b), the oil passage 18 connects the neutral position (B) of the three-position switching valve 12 and the pilot pump. Tie through. Therefore, the variable relief valves 16L, 16R
Are both low pressure sets. At the left and right positions (a) and (c) switched by the operating pressure, one variable relief valve is connected to the tank via the three-position switching valve 12. That is, when the operation lever is operated to the left, the operation pressure of the oil passage 14 acts to switch to the position (a). Then, the switching valve 12 switches to the position A. Then, the variable relief valve 16L communicates with the tank via the switching valve 17.

At the time of stoppage, the pressure P _{2 in the} main line 8 decreases and the pressure P _{1 in the} main line 7 increases, but the pressure gradient dp ₁ / dt
Since (dp ₂ / dt) is relatively slow, the switching valve 12 is shifted from the position (C) to the intermediate position (B) when P ₁ = P ₂ . At this time, the pressure of the pilot pump led from the switching valve 17 acts on the variable relief valve, and both the variable relief valves 16L and 16R are set to a low pressure. For this reason, the pressures P ₁ and P ₂ of the main pipelines 7 and 8 rapidly become the same pressure, thereby preventing reversal.

When inching deceleration, that is, when the operation lever is gradually returned to neutral, P ₁ > P _{2 is changed} to P ₂ > P _1. However, since the pressure gradient dp ₂ / dt is steep, the switching valve 12 is set to ( From position A) to position (C). Since the pressure from the pilot pump is cut off and the variable relief valve 16R communicates with the tank and has a low pressure, both the variable relief valves 16R are set to a high pressure, so that shock is reduced and operability is improved.

[0022]

EFFECT hydraulic motor - both ports of motor 4 - variable Lili between main conduit 7, 8 are connected to the bets - off valve 16L, provided with a 16R, switching the pressure P ₁ and P ₂ of the main conduit 7, 8 An alternate switching valve 12 is provided so that the set pressure of the variable relief valves 16L and 16R can be controlled to a relief pressure corresponding to the manipulated variable when decelerating and to a low pressure relief pressure when stopped.

In this way, when the operating lever is returned to neutral, the high-pressure relieving during rapid deceleration, the relieving pressure corresponding to the operation amount and the braking pressure corresponding to the operating method during inching deceleration are performed. Operability has been further improved because of the occurrence. Further, since the reversal at the time of stopping the turning is prevented, the operability is further improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an operating pressure and a variable relief valve pressure.

FIG. 3 is a graph showing the relationship between acceleration, pressure, velocity of an inertial body, and time with respect to displacement of the operation lever when the operation lever is suddenly returned to neutral.

FIG. 4 is a graph showing a relationship between acceleration, pressure, speed of inertial body and time with respect to displacement of the operation lever when the operation lever is gradually returned to neutral.

FIG. 5 is a circuit diagram of a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a conventional inertial body control device.

FIG. 7 is a graph showing the relationship between acceleration, pressure, velocity of inertial body and time with respect to displacement of an operation lever.

FIG. 8 is another circuit diagram of a conventional inertial body control device.

9 is a graph showing the relationship between acceleration, pressure, speed, and time with respect to displacement of the operation lever in the conventional example shown in FIG.

[Explanation of symbols]

 1 Hydraulic pump 2 Directional control valve 3 Remote control valve 4 Hydraulic motor 5 Inertial body 6 Relief valve 7,8 Main line 9 Reverse check valve 12 Switching valve 13 Shuttle valve 14 Oil line 15 Oil line 16,16L, 16R Variable Relief valve 17 Switching valve 18 Oil passage

Claims (2)

(57) [Scope of request for utility model registration] 1. A pair of hydraulic motors (4) provided between main pipes (7, 8) connected to both ports of the hydraulic motor (4). When the operating pressure increases, the variable relief valve pressure decreases. Variable relief valve (1
6L, 16R) and the left and right (A) from the neutral position (B) by the pressure of the larger of the pressures P ₁ and P ₂ of the main conduit (7, 8)
(C) Three-position switching valve (12) for switching to the position, and main lines (7, 8)
From the shuttle valve (13) provided through the pressure of a larger one of the pressure P ₁ and P ₂ of the main conduit (7, 8) between the 3-position switching valve (12) is the pair of variable Lili - F valve (16L) and (16R)
And a port connected to a shuttle valve (13) connected between the oil passages (14 and 15) leading to the remote control valve (3) and the main lines (7, 8). At the neutral position (B) of the three-position switching valve (12), almost zero pressure in the main lines (7, 8) passes from the shuttle valve (13) to the pair of variable relief valves (16L, 16R), the variable Lili via the Tsu switchable pressure P ₁ of the main path (7) (a) operating pressure oil passage from the remote control valve (3) at the position (15) - off valve and (16L), also the main conduit ( variable Lili via pressure P ₁ is a shuttle valve (13) 7) - as communicating with off valve (16R),
Further main channel (8) was Tsu switchable pressure P ₂ of (C) the pressure P ₂ is variable Lili through shuttle valve (13) of the main conduit at the position (8) -
Operating pressure from the valve (16L) and the remote control valve (3)
By connecting to the variable relief valve (16R) through (14), the set pressure of the pair of variable relief valves (16L, 16R) is reduced to the relief pressure corresponding to the manipulated variable during deceleration. An inertial body control device characterized in that it can be controlled to a low pressure relief pressure when stopped. 2. A pair of hydraulic motors (4), which are provided between main pipelines (7, 8) connected to both ports of the hydraulic motor (4), and when the operating pressure increases, the variable relief valve pressure decreases. Variable relief valve
(16L, 16R) and the pressure P ₁ and the larger the neutral position by the pressure of one of the P ₂ (B) from the left (A) and the position (C) position and the Setsu換Ru 3 main conduit (7, 8) Three positions for switching from the neutral position (b) to the left and right positions (a) and the position (c) by operating pressure passing through the position switching valve (12) and the operating pressure oil passages (14, 15) of the remote control valve (3) The three-position switching valve (12) includes a port connected to a pair of variable relief valves (16L and 16R), and two operating pressure oil passages (14, 14) of a remote control valve. A port leading to 15) and a port leading to another three-position switching valve (17),
The three-position switching valve (17) is a port connected to the switching valve (12).
And a port communicating with the pilot pump and the tank, and a pair of relief valves (16L, 16R) of the three-position switching valve (12) at the neutral position (b) of the three-position switching valve (17). The neutral position (B) and the pilot pump are connected via an oil passage (18). The left and right positions (a) and (c) are switched by the switching pressure from the remote control valve (3). Disconnect 3
The port connected to the position switching valve (12) is configured to pass through the tank, and the set pressure of the pair of variable relief valves (16L, 16R) is reduced to a relief pressure corresponding to the operation amount when decelerating. An inertial body control device characterized in that it can be controlled to a low pressure relief pressure when stopped.