JP2000145706A - Hydraulic motor device having relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the operating pressure of a relief valve to two steps by very simple means to surely keep low pressure at low pressure time while smoothing a boost pattern, when a brake is started, at high pressure setting time. SOLUTION: In this hydraulic motor device having relief valves 50A, 50B constituted to be arranged by branching in both pipe lines of a hydraulic motor 52 driving an inertia load 56 by pressure oil supplied/discharged through a switching valve 58 from a hydraulic pump 60 to be moved to open against spring elastic force with one end of a poppet press abutting to its back part by a pressure rise of supply ports 70A, 70B, in the cases of start accelerating and deceleration stopping the rotation of the hydraulic motor to relieve pressure oil thereof to an outlet, also to introduce the pressure oil of the supply port to a spring seat piston chamber 86 through a compensation flow regulating means 90 to move a spring seat piston 80 press abutting to the other end of a spring to gradually compress the spring so as to adjust a relief pressure, a load of a spring 97 setting a differential pressure of the pressure compensation flow regulating means 90 is constituted so as to be adjustable by an external signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic motor device having a relief valve applicable to an inertial body drive circuit for controlling a turning drive device of a hydraulic shovel or the like.

[0002]

2. Description of the Related Art In general, an inertial body drive circuit is configured to control the drive direction of a hydraulic motor by controlling the rotation direction and stop of hydraulic oil of a hydraulic pump by a switching valve. Therefore, when the hydraulic motor is rotating in one direction, the switching valve is returned to the neutral position to stop driving the inertial body.
The return path of the hydraulic motor is closed by the switching valve,
The inertial body has inertial rotational force, and the hydraulic pressure on the return side rises sharply, increasing energy, causing a shock,
The gears of the hydraulic motor may be damaged.

For this reason, it has been conventionally proposed to install a relief valve in a hydraulic circuit to prevent a sudden increase in hydraulic pressure (Japanese Utility Model Publication No. 63-21814).

That is, the relief valve according to this proposal is:
When the pressure in the supply passage 2 is low, the relief valve 1 is in a non-operating state and the outer poppet 4
Is pressed to the left by a spring 7 via a receiver 5 and a spring receiver 6 to come into contact with the seat 8 and a spring seat piston 9
Is located in contact with the plug 10, and shuts off the supply passage 2 and the return passage 3 as shown in FIG.

Therefore, when the pressure in the supply passage 2 rises,
This pressure oil acts on the outer poppet 4, moves the outer poppet 4 rightward against the elasticity of the spring 7, and
And the return passage 3 to start the relief action. On the other hand, the pressure oil is supplied to the eccentric hole 11 of the outer poppet 4 and the hole 1.
2 flows into the axial passage 13 through the
4. Spring seat piston chamber 17 through annular groove 15 and passage 16
Will be introduced. The pressure oil in the spring seat piston chamber 17 moves the spring seat piston 9 to the left from the illustrated position against the elasticity of the spring 7 in response to the increase in the pressure of the supply passage 2.

As a result, the spring 7 is further compressed, so that the relief pressure increases. By the movement of the spring seat piston 9, the lateral hole 14 of the rod 18 gradually decreases the opening area, thereby reducing the amount of pressure oil to the spring seat piston chamber 17. Further, the spring seat piston 9 moves,
Since the opening of the lateral hole 14 is closed and the flow of the pressure oil into the spring seat piston chamber 17 is substantially eliminated, the spring seat piston 9
The left-end position of is maintained.

As described above, the increase in the set pressure becomes gentler as it approaches the upper limit value, so that the shock caused by the sudden rise pressure when the relief valve 1 is started can be reduced. When the pressure of the supply passage 2 becomes equal to or less than the set value, the pressure of the spring seat piston chamber 17 acting on the right end face of the spring seat piston 9 decreases, and the spring seat piston 9 moves to the position shown in FIG. Return to and prepare for the next operation.

Therefore, in the relief valve configured as described above, when the pressure in the supply passage 2 rises, the outer poppet 4 first moves rightward against the elasticity of the spring 7 and at the same time, the spring seat piston 9 Pressure oil flows into the right spring seat piston chamber 17, and the spring seat piston 9 moves to the left to compress the spring 7 and increase its elastic force (relief pressure). With the leftward movement of the spring seat piston 9, the opening area of the lateral hole 14 into which the pressure oil flows into the spring seat piston chamber 17 becomes small. The relief pressure balanced with the elastic force of the spring 7 compressed between the spring seat piston 9 and the spring receiver 6 held at the pressure becomes the set pressure, and has an effect of reducing the pressure peak at the time of starting the relief valve 1. Can be done.

However, in the relief valve having the above-described structure, the pressure oil action area of the spring seat piston 9 is determined by the outer diameter of the spring seat piston 9 fitted in the hole 20 of the cap forming the spring chamber 19 in which the spring 7 is loaded. And a relatively large area in a ring shape sandwiched between the inner diameter of the inner hole 21 of the spring seat piston 9 into which the rod 18 is inserted. The spring seat piston 9 starts to move to the left even at a pressure as low as the back pressure generated in the return passage during the rotation of the spring, and when the pressure in the supply passage 2 rises, the pressure oil is supplied to the spring seat piston chamber 17. The horizontal hole 14 necessary for inflow of air is already closed because the spring seat piston 9 has already moved to the left. After the horizontal hole 14 is closed, a large peak is eliminated to reduce shock. It has not been possible.

[0010] From such a viewpoint, the present applicant firstly
When the pressure in the supply passage increases, the spring is compressed to increase the relief pressure so that the pressure oil working area of the spring seat piston can be reduced. A patent was developed to obtain a patent for a hydraulic motor relief valve that eliminates pressure peaks at the start of the relief valve and reduces shock when the pressure in the supply passage rises without moving and the pressure rises. No. 2571928).

That is, as shown in FIGS. 9 and 10, a relief valve of a hydraulic motor according to this patent drives an inertial load with pressure oil supplied and discharged from a hydraulic pump 22 via a switching valve 23. When the rotation of the hydraulic motor is stopped, the pressure in the supply port causes the poppet 25 to move and open against the spring 26 that presses one end against its back when the rotation of the hydraulic motor is stopped. By releasing the pressure oil to the outlet and introducing the pressure oil from the supply port to the spring seat piston chamber 27 via the throttle 28, the spring seat piston 29 pressed against the other end of the spring 26 is moved. In the relief valves 30A and 30B of the hydraulic motor 24 for moving and compressing the spring 26 to adjust the relief pressure, an inner hole 32 having a step diameter smaller than the inner hole 31 loaded with the spring 26 is provided. The spring seat piston 29 having a reduced pressure oil action area is movably fitted to hold the spring seat piston 29 at the initial position at a pressure of about the back pressure generated in the return passage when the hydraulic motor rotates. It is configured not to be moved.

However, the relief valves 30A, 30B
9 and 10, when the switching valve 23 is in the neutral state shown in the drawing, there is no pressure in the supply passages 32A and 32B, that is, the supply port 33 in FIG. 10, and the relief valves 30A and 30B are in the non-operating state. The tip of the poppet 25 is pressed leftward by the elastic force of the spring 26 and is in contact with the valve seat of the seat 34, so that the supply port 33 and the outlet 35 are shut off.

When the switching valve 23 is switched from the neutral position to the upper position, the pressure oil of the hydraulic pump 22 is supplied to the switching valve 23.
The hydraulic fluid flows into the hydraulic motor 24 from the pipe 36 through the pipe 36 and rotates in one direction, and the hydraulic oil discharged from the hydraulic motor 24 flows from the pipe 37 through the switching valve 23 to the tank 38.
It is returned. Next, when the switching valve 23 is switched to the neutral position in order to stop the hydraulic motor 24 from the rotating state, the circuits of the hydraulic pump 22 and the tank 38 are cut off in the pipes 36 and 37, respectively. , The hydraulic motor 24 does not stop immediately and the pressure in the conduit 37 rises. Therefore, the pressure at the supply port 33 of the relief valve 30B rises through the supply passage 32B, and the poppet 2
5, the supply port 33 has an effective sectional area formed by the difference (D1> D2) between the valve seat diameter D1 of the seat 34 and the diameter D2 of the rod 40.
The force of the pressure oil acts to move to the right against the elastic force of the spring 26, and the supply port 33 and the outlet 35 are communicated through the opened valve seat of the seat 34 and the lateral hole 41. This starts the relief action.

At the same time, the pressure oil in the supply port 33 is
5 and the passage 4 from the passage 42 of the rod 40 through the throttle 28
3 and is introduced into the spring seat piston chamber 27, and the pressure oil in the spring seat piston chamber 27 increases in pressure in response to the increase in the pressure in the supply port 33, and causes the spring seat piston 29 to move into the spring 26.
To the left against the elasticity of As a result, the spring 2
6 is further compressed and the relief pressure increases. The leftward movement of the spring seat piston 29 is stopped by moving the stroke L until the left side surface 45 of the flange portion 44 of the spring seat piston 29 comes into contact with the wall surface 47 of the valve body 46 with the increase in the pressure of the spring seat piston chamber 27. The relief pressure at the time of the stop is the set pressure.

[0015] The pressure oil thus relieved is:
The outlet 35 is supplied to the hydraulic motor 24 through the outlet passage 48B and the check valve 49A in FIG.

The flow of the pressure oil into the spring seat piston chamber 27 is gentle because the throttle 28 is provided in the middle of the passage 42 and the passage 43, and therefore the relief pressure rises slowly, and the pressure rises sharply. Has alleviated the shock. Further, it is also possible to increase the set pressure by increasing the stroke L in which the spring seat piston 29 moves.

[0017]

In the above-described relief valve of a hydraulic motor according to the prior art, as shown in FIG. 9, the supply port 32A, that is, the supply port 33 in FIG.
Rises, the pressure flows into the spring seat piston chamber 27 through the passage 42 provided inside the poppet 25. Further, the inflowing pressure oil acts on the spring seat piston 29. When the pressure oil exceeds a certain value, the spring oil is moved to the left in the drawing while compressing the spring 26 against the load of the spring 26.

In this movement process, since the pressure oil flows into the spring seat piston chamber 27 through the throttle 28, it takes some time for the spring seat piston 29 to move from the illustrated position to the position in contact with the chamber wall 47. When the poppet 25 of the relief valve performs an opening operation in this process, the poppet 2
The load of the spring 26 acting on the spring 5 is initially from the position shown in the drawing, and finally becomes the load at the position where the spring seat piston 29 abuts the chamber wall 47. It gradually increases in accordance with the movement of the spring seat piston 29, and the dynamic characteristics as shown in FIG. 5 are obtained.

In a hydraulic circuit for driving a large inertia body, for example, an upper swing body of a hydraulic excavator, a relief valve of the swing motor as described above is often used, and a good result is obtained for reducing shock during braking. .

However, in the case of a hydraulic shovel or the like, the turning inertia is significantly different between a case where the boom and the arm are closer to the center of rotation and a case where the boom and the arm are closer to the horizontal state and a load is loaded on the bucket. . For this reason, in the above-described conventional technology, the shock immediately after the relief valve is actuated is reduced, but the pressure rise pattern is the same regardless of the difference in inertia due to the arm, boom posture, the presence or absence of the bucket load, and the like. For example, if the relief pressure is set in accordance with the state of small inertia, the flow angle at the time of the turning brake is large under the operating condition with large inertia, and if the relief pressure is set in accordance with the state of the large inertia, the inertia is reduced. Under the conditions, there is a problem in that the advantage of the hydraulic brake for turning becomes excessive, and smoothness at the time of stopping is impaired.

Japanese Patent Application Laid-Open No. Hei 6-173299 discloses a method for varying the set pressure of a relief valve for turning a hydraulic excavator in accordance with its posture, load conditions, and the like. However, in this prior art, since the set pressure is adjusted by an external signal, the structure of the relief valve becomes very complicated, not only increases the manufacturing cost, but also increases the reliability. There are difficulties that require consideration. Although it is possible to adjust the set pressure of the relief valve itself, when the set pressure is set to a relatively high pressure, it is possible to adopt a boost pattern in which the characteristics at the time of start and stop are gradually increased. However, there is still a problem that a shock remains at the time of deceleration stop.

Accordingly, the present inventors have conducted intensive studies and as a result, have found that both hydraulic motors for driving an inertial load formed by an upper swing body of a hydraulic shovel by hydraulic oil supplied and discharged from a hydraulic pump via a switching valve. When the rotation of the hydraulic motor is started, accelerated and decelerated and stopped, the poppet moves and opens against the spring elasticity of pressing one end against its back due to the increase in the pressure of the supply port. By relieving the pressure oil to the outlet and introducing the pressure oil from the supply port to the spring seat piston chamber via the pressure compensation flow rate adjusting means, the spring seat piston pressed against the other end of the spring is moved. In the hydraulic motor device having a relief valve configured to move and adjust the relief pressure by gradually compressing the spring, the load of the spring for setting the differential pressure of the pressure compensating flow rate adjusting means is externally adjusted. It was ascertained by adjustably constituting, that can be obtained hydraulic motor device having a relief valve which can optimally set a deceleration stop and start acceleration performance of the hydraulic excavator by No..

Accordingly, an object of the present invention is to set the operating pressure of the relief valve in two stages by a very simple means, to smooth the pressure increasing pattern at the start of braking when high pressure is set, and to ensure the pressure increase pattern at low pressure. Another object of the present invention is to provide a hydraulic motor device having a relief valve configured so that a low pressure can be maintained.

[0024]

In order to achieve the above object, a hydraulic motor device having a relief valve according to the present invention drives an inertial load by pressure oil supplied and discharged from a hydraulic pump via a switching valve. The branch is disposed in both pipelines of the hydraulic motor, and when the rotation of the hydraulic motor is started, accelerated, decelerated and stopped, the pressure rises at the supply port so that the poppet moves against the spring elasticity of pressing one end against its back. The pressure oil of the supply port was introduced into the spring seat piston chamber via the pressure compensation flow rate adjusting means, and was pressed against the other end of the spring. In a hydraulic motor device having a relief valve configured to adjust a relief pressure by moving a spring seat piston to gradually compress the spring, a spring for setting a differential pressure of the pressure compensation flow rate adjusting means is provided. A load, characterized in that adjustably constructed by an external signal.

In this case, the inertial load is an upper revolving structure having an actuator including an arm, a boom, and a bucket of a hydraulic shovel, and an external signal for adjusting a load of a spring corresponds to an angle of the boom with respect to the upper revolving structure. It can be a signal.

The inertial load is an upper revolving structure having an actuator including an arm, a boom, and a bucket of a hydraulic shovel, and an external signal for adjusting a load of a spring is a signal corresponding to a holding pressure of a boom cylinder. You can also.

On the other hand, each port of the hydraulic motor is provided with a relief valve, and the load of each spring for adjusting the differential pressure of the pressure compensation flow rate adjusting means provided on each relief valve is applied to the hydraulic motor device. The load of each of the springs can be simultaneously adjusted by an external signal connected to a single signal port.

In this case, the load of the spring for adjusting the differential pressure of the pressure compensation flow rate adjusting means can be configured to decrease as the external signal increases.

Further, a plurality of springs for adjusting the differential pressure of the pressure compensating flow rate adjusting means are provided. In addition to receiving the load of the spring, when the external signal becomes equal to or more than a predetermined value, it can be configured to receive only the load of the single spring.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a hydraulic motor device having a relief valve according to the present invention will be described in detail with reference to the accompanying drawings.

[0031]Example 1  1 and 2 show an oil having a relief valve according to the present invention.
1 shows an embodiment of a pressure motor device. That is,
FIG. 1 is a sectional view of a main part of a hydraulic motor device having a relief valve.
Fig. 2 shows the connection between the
The hydraulic system diagram of the entire hydraulic motor device having a valve
It is.

1 and 2, reference numerals 50A and 50B indicate relief valves attached to the hydraulic motor 52, respectively. These relief valves 50
A and 50 </ b> B are built in the cover 54 of the hydraulic motor 52. Then, the hydraulic motor 52 has an inertia load 56.
(When the present invention is applied to a hydraulic shovel, the upper slewing body including actuators such as arms, booms, and buckets of the hydraulic shovel) is driven. The hydraulic motor 52 is supplied and discharged with pressure oil between a hydraulic pump 60 and a tank 62 via a switching valve 58. In this embodiment, an example of the configuration of the switching valve 58 is shown in FIG. 1. However, the hydraulic pump 60 is provided with a switching valve of another actuator (not shown) of the hydraulic shovel.
For example, a switching valve of an arm cylinder or the like is generally connected.

The first relief valve 50A will now be described with reference to FIG.

A relief valve assembly 64 is incorporated in the cover portion 54 of the hydraulic motor 52 so as to be incorporated in a sleeve 66, and a seat 68 attached to the end of the sleeve 66.
However, the supply port 70A and the low-pressure chamber (outlet) 72 are liquid-tightly shut off. In the sleeve 66, a spacer 74, a poppet 78 having a rod 76, a spring seat piston 80, and a spring 8 having one end in contact with the poppet 78 and the spacer 74 supported by the spring seat piston 80.
2 is included. Note that the poppet 78 is
8 with the diameter d1 of the rod 76, and the diameter d2 of the rod 76.
The pressure difference of the supply port 70A acts on the area difference between (d2 <d1). And, on the rod 76,
An orifice 84 is provided for maintaining stability when the relief valve 64 operates.

However, the spring seat piston 80 has a diameter d in the spring seat piston chamber 86 relative to the sleeve 66.
The spring seat piston chamber 86 is closed by a cap 88 after the spring seat piston 80 is attached to the sleeve 66. The spring seat piston 80 is provided in the spring seat piston chamber 8.
6, the distance S until the shoulder 80a comes into contact with the wall surface 66a of the sleeve 66 can be moved. In addition,
The movement of the spring seat piston 80 is caused by the movement of the spring seat piston chamber 8.
In contrast, the pressure oil that has flowed in through a path described later acts on the right end of the spring seat piston 80, thereby moving the spring 82 to the left in the drawing while compressing the spring 82.

In this embodiment, the relief valves 50A, 50A attached to the cover 54 of the hydraulic motor 52 are used.
Since B has the same configuration, only one relief valve 50A will be described, and the other relief valve 50B will be given the same reference numeral for the same component and will not be described in detail.

Therefore, in this embodiment, the supply port 70
Pressure compensation flow rate adjusting means 90 is provided between A and the spring seat piston chamber 86. The ports of the switching valve 58 are connected to the respective ports Mp1 and Mp2 of the hydraulic motor 52, and the supply port 70A of the relief valve 50A is
It is connected to a port Mp1 on one side of the hydraulic motor 52, and is connected to a spring seat piston chamber 86 via a passage 92, the pressure compensation flow rate adjusting means 90 and passages 94 and 66b.

In such a state, when the hydraulic motor 52 is driven by operating the switching valve 58 and then decelerated and stopped, it is assumed that an operating pressure of the hydraulic brake is generated at one port Mp1 of the hydraulic motor 52. As for the operating pressure of the relief valve 50A, first, at the time of starting, since the spring seat piston 80 is at the illustrated position, the relief valve 50A operates in a state where the load of the spring 82 is minimum, that is, at a low pressure. At the same time, when the pressure oil at the supply port 70A flows into the spring seat piston chamber 86 via the above-described passage, it tries to flow at the flow rate determined by the pressure compensation flow rate adjusting means 90 regardless of the pressure at the supply port 70A. .

The pressure-compensating flow control means 90 comprises a pressure-compensating flow control spool 96 and a spring 97. The pressure-compensating flow control spool 96 has a fixed throttle 98 communicating with a passage 92 communicating with the supply port 70A. An opening 99 is provided in a passage 94 communicating with the spring seat piston chamber 86. Therefore, when the load of the spring 97 acting on the pressure compensation flow control spool 96 is constant, when the pressure oil flows from the passage 92 to the passage 94, the differential pressure in the fixed throttle 98 is independent of the pressure in the passage 92. The opening of the opening 99 is automatically adjusted so as to be equal to the pressure corresponding to the case of the load of the spring 97. In this manner, when the pressure of the supply port 70A is increased, regardless of the pressure, the amount of oil (per unit time) flowing into the spring seat piston chamber 86 via the pressure compensation flow rate adjusting means 90 depends on the area of the fixed throttle 98. Because it is a predetermined constant value,
The value is uniquely determined according to the load of the spring 97.

In this embodiment, however, one end of the pressure compensation flow rate adjusting means 90 is brought into contact with the spring 97 in the vicinity of the pressure compensating flow rate adjusting means 90 and the other end receives the spring 100 between the cap 108 and the other end. A stepped piston 104 which has a diameter difference between the small diameter part d4 and the large diameter part d5 and houses the piston 102 in the inner diameter part d6 in a liquid-tight and slidable manner.
Is arranged. The stepped piston 104 has an oil chamber 105 opened at one end of the piston 102 at an inner diameter portion d6.
A passage 106 is provided for connecting the pressure compensation flow rate adjusting means 90 with the oil chamber 95 provided with the spring 97. Further, the stepped piston 104 is slidably and liquid-tightly inserted into a stepped hole provided in the cover portion 54 so as to conform to the outer dimensions of the small diameter portion d4 and the large diameter portion d5. , And the other end of the piston 102 is closed and held by a cap 108.

The stepped piston 104 is moved to an oil chamber 109 formed by a stepped portion of a stepped hole provided in the cover portion 54 and a stepped portion of the stepped piston 104. It is configured to move rightward in the figure against the elasticity of the spring 100 by a signal pressure supplied from outside via the signal port 110.

The small outer diameter portion d4 and the inner diameter portion d6 formed on the stepped piston 104 are both set to be equal (d4 = d6). Therefore, even if the pressure in the oil chamber 95 changes, this pressure is not applied. The left and right forces shown on the stepped piston 104 are always cancelled, and the spring 100
Is set to a relatively large value as compared with the load of the spring 97.

In the hydraulic motor device of the present embodiment having the above-described configuration, for example, when an external signal pressure is applied to the signal port 110 via the external signal line 111 and the signal pressure is gradually increased, the stepped piston 104 In response to the rise of the signal pressure, the spring 100 moves to the right in the figure while compressing the spring 100 against its elasticity. Along with this,
The mounting length of the spring 97 is extended and the load of the spring 97 on the pressure compensation flow control spool 96 is reduced, and the differential pressure at the fixed throttle 98 is correspondingly reduced. Also decreases in response to the decrease in the differential pressure.

Therefore, the flow rate (per unit time) flowing into the spring seat piston chamber 86 from the supply port 70A also corresponds to the signal pressure supplied to the signal port 110, and furthermore, the supply oil amount according to the increase of the supply signal pressure. , That is, the moving speed of the spring seat piston 80 decreases, and the relief valve 50
The pressure rise time from the initial operating pressure P1 of A to the final set pressure PS becomes longer.

In FIGS. 1 and 2, when the signal pressure is supplied to the external signal line 111, the signal switching means 112 and the signal operation from the signal generation means 113 to the switching means 112 cause the signal generation hydraulic pressure to be increased. Pump 1
The switching operation is performed by transmitting the hydraulic pressure signal from 14. 1 and 2, reference numerals 115A and 115B denote check valves, 116 denotes a check valve with spring, and 117 denotes a tank.

Therefore, the operating characteristic of the relief valve in the hydraulic pump device according to the present embodiment has a pressure increasing pattern as shown in FIG. In FIG. 3, the initial pressure P1 is the same as in FIG.
5 shows a case where the spring seat piston 80 is in the position shown in the drawing, and the final set pressure PS shows a case where the spring seat piston 80 is in the position where the maximum stroke S has been moved. Then, the time required to increase the pressure from the initial pressure P1 to the final set pressure PS is referred to as a slow pressure increase time (Δt1 to Δt3).

In the step-up pattern shown in FIG. 3, the hydraulic motor device having the relief valve of this embodiment is, for example, shown in FIG.
As shown in FIG. 7, when the present invention is applied to a hydraulic excavator, the condition for applying an external signal pressure to the pressure-compensating flow rate adjusting means 90 is as follows. By setting to adjust according to the load pressure of
When the inertia of the upper-part turning body having the actuator including the arm, the boom, and the bucket as the inertial load is large (see FIG. 7), the external signal pressure is reduced and the pressure waveform A-
When the pressure rising time of the relief valve is shortened as shown in FIG. 1 and the inertia of the upper swing body is small (see FIG. 6), the pressure rising of the relief valve is increased as shown in the pressure waveforms A-2 and A-3. By adjusting the external signal pressure in accordance with changes in the posture of the hydraulic shovel, the load condition of the bucket, and the like so as to lengthen the time, optimal startup acceleration and deceleration stop characteristics can be exhibited. And in this case,
Under the condition that the external signal pressure does not act, the boosting time is the shortest. Therefore, even when the external signal pressure is shut off due to an unexpected situation, the relief valve operates reliably when the inertial body stops, so that more safe characteristics are obtained. be able to.

[0048]Example 2  4A and 4B show a relief valve according to the present invention.
9 shows another embodiment of the hydraulic motor device having
You. That is, FIGS. 4A and 4B show pressure compensation.
3 shows the configuration of a flow rate adjusting means 90 and its control means.
You.

In this embodiment, the differential pressure setting spring 97 of the pressure compensating flow rate adjusting means 90 is additionally provided to provide two springs (97, 9).
7 '), when no external signal pressure is applied, these two springs 97, 97' both apply a load to the pressure compensation flow control spool 96 of the pressure compensation flow adjusting means 90 [FIG. (See FIG. 4A), and when the external signal pressure exceeds a predetermined value, only a single spring 97 'applies a load to the pressure compensation flow control spool 96 [see FIG. 4B]. It is what was constituted.

With such a configuration, the operating characteristic of the relief valve has a step-up pattern as shown in FIG. 5 due to the difference in the external signal pressure. That is, in the pressure rising pattern shown in FIG. 5, the pressure waveform B-1 is the case of FIG. 4A, the slow pressure rising time Δt1 is shortened, and the pressure waveform B-2 is the case of FIG. And the gradual boosting time Δt
2 is set longer.

In this embodiment, similarly to the above-described embodiment, a hydraulic motor device having a relief valve is shown in FIG.
As shown in FIG. 7, when the present invention is applied to a hydraulic shovel, an angle θ of the boom of the hydraulic shovel with respect to the upper swing body is detected as a condition for applying an external signal pressure to the pressure compensation sum flow rate adjusting means. For example, when the boom is closer to horizontal (see FIG. 7), no external signal is given,
When the boom is more perpendicular to the upper swing body (see FIG. 6), by providing an external signal, it is possible to optimally set the start-up acceleration and deceleration stop performance of the excavator.

Further, the holding pressure of the boom cylinder is detected,
When the holding pressure is high, no external signal is given, and when the holding pressure is lower than a predetermined pressure, an external signal is given. By providing the switching signal pressure to the compensation flow rate adjusting means, it is possible to optimally set the start-up acceleration and deceleration stop performance of the hydraulic shovel.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and many design changes can be made without departing from the spirit of the present invention.

[0054]

As is apparent from the above-described embodiment, the hydraulic motor device having the relief valve according to the present invention is a hydraulic motor that drives an inertial load by pressure oil supplied and discharged from a hydraulic pump via a switching valve. Branching into both pipelines,
When the rotation of the hydraulic motor is started, accelerated, decelerated and stopped, the pressure of the supply port increases and the poppet moves and opens against the spring resilience of pressing one end against its back, and the pressure oil is relieved to the outlet. By introducing the pressure oil of the supply port to the spring seat piston chamber via the pressure compensation flow rate adjusting means, the spring seat piston pressed against the other end of the spring is moved, and the spring is gradually compressed. A hydraulic motor device having a relief valve configured to adjust the relief pressure by adjusting the load of a spring for setting the differential pressure of the pressure compensation flow rate adjusting means by an external signal, thereby providing a hydraulic shovel. Even if the inertia of the inertial body is different depending on the machine posture and working conditions, the hydraulic brake function when decelerating and stopping this inertial body by an external signal The boosting time of the relief valve to perform, can be adjusted by very simple way, it is possible to obtain an optimum deceleration stop and start acceleration characteristics regardless the working conditions and the posture. Further, the hydraulic motor device of the present invention is configured so that the boosting time is the shortest even when the external signal is interrupted, and thus has an excellent feature in safety.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a connection state between a main part cross-sectional structure and a hydraulic system showing an embodiment of a hydraulic motor device having a relief valve according to the present invention.

FIG. 2 is a hydraulic system diagram of the entire hydraulic motor device having the relief valve shown in FIG.

FIG. 3 is a waveform chart showing pressure operation characteristics of a relief valve in the hydraulic motor of the embodiment shown in FIG.

FIGS. 4 (a) and 4 (b) show another embodiment of a hydraulic motor device having a relief valve according to the present invention, and are enlarged cross-sectional views of main parts showing operating states.

FIG. 5 is a waveform diagram showing pressure operation characteristics of a relief valve in the hydraulic motor of the embodiment shown in FIG.

FIG. 6 is an explanatory diagram showing a state where the turning inertia is relatively small in the case of a hydraulic shovel as an inertial load.

FIG. 7 is an explanatory diagram showing a state where the turning inertia is relatively large in the case of a hydraulic shovel as an inertial load.

FIG. 8 is a cross-sectional view of a main part showing one configuration example of a relief valve of a conventional hydraulic motor.

FIG. 9 is an explanatory diagram showing a schematic configuration of another configuration example of a conventional relief valve of a hydraulic motor and a system arrangement thereof.

FIG. 10 is an enlarged sectional view of a main part of the relief valve shown in FIG.

[Explanation of symbols]

 50A, 50B Relief valve 52 Hydraulic motor 54 Cover portion 56 Inertial load 58 Switching valve 60 Hydraulic pump 62 Tank 64 Relief valve assembly 66 Sleeve 66a Wall surface 66b Passage 68 Seat 70A, 70B Supply port 72 Low pressure chamber 74 Spacer 76 Rod 78 Poppet 80 Spring Seat piston 80a Shoulder portion 82 Spring 84 Orifice 86 Spring seat piston chamber 88 Cap 90 Pressure compensation flow rate adjusting means 92 Passage 94 Passage 95 Oil chamber 96 Pressure compensation flow rate control spool 97, 97 'Spring 98 Fixed throttle 99 Opening 100 Spring 102 Piston 104 stepped piston 105 oil chamber 106 passage 108 cap 109 oil chamber 110 signal port 111 external signal line 112 signal switching means 113 signal generating means 114 signal generating hydraulic pump 11 A, 115B check valve 116 spring-loaded check valve 117 tank

Continued on the front page (72) Inventor Koji Takanashi 4-5676 Hibarigaoka, Zama-shi, Kanagawa F-term (reference) in Sagami Works of Toshiba Machine Co., Ltd. 2D003 AA01 AB02 AB03 BA07 BB03 BB10 BB12 CA02 3H089 AA65 BB08 CC08 DA03 DB03 DB14 DB47 DB49 EE04 EE22 EE31 GG02 JJ02

Claims (6)

[Claims] 1. A hydraulic motor that drives an inertial load with pressure oil supplied and discharged from a hydraulic pump via a switching valve and is branched and disposed on both pipelines to start, accelerate, decelerate and stop the rotation of the hydraulic motor. When the pressure rises at the supply port, the poppet moves and opens against the spring resilience of pressing one end against its back, and the pressure oil is relieved to the outlet, and the pressure oil at the supply port is released from the spring seat piston. A relief configured to be introduced into the chamber through a pressure-compensating flow rate adjusting means to move a spring seat piston pressed against the other end of the spring to gradually compress the spring to adjust the relief pressure. A hydraulic motor device having a relief valve, wherein a load of a spring for setting a differential pressure of the pressure compensating flow rate adjusting means can be adjusted by an external signal. . 2. An inertia load is an upper revolving structure having an actuator including an arm, a boom, and a bucket of a hydraulic shovel, wherein an external signal for adjusting a load of a spring is provided by a signal corresponding to an angle of the boom with respect to the upper revolving structure. A hydraulic motor device having a relief valve according to claim 1, comprising: 3. An inertia load is an upper revolving structure having an actuator including an arm, a boom, and a bucket of a hydraulic shovel, wherein an external signal for adjusting a load of a spring is a signal corresponding to a holding pressure of a boom cylinder. A hydraulic motor device having a relief valve according to claim 1, comprising: 4. A relief valve is provided at each port of the hydraulic motor, and the load of each spring for adjusting the differential pressure of the pressure compensation flow rate adjusting means provided at each of the relief valves is reduced by a single load to the hydraulic motor device. The hydraulic motor device having a relief valve according to any one of claims 1 to 3, wherein a load of each of the springs is simultaneously adjusted by an external signal connected to a signal port. 5. The hydraulic motor device having a relief valve according to claim 4, wherein a load of a spring for adjusting a differential pressure of the pressure compensation flow rate adjusting means is reduced as an external signal increases. 6. A pressure compensating flow rate control means comprising a plurality of springs for adjusting a differential pressure of the pressure compensating flow rate adjusting means.
When the external signal does not act or is relatively low, the load of the plurality of springs is received, and when the external signal exceeds a predetermined value, only the load of the single spring is received. A hydraulic motor device having a relief valve according to claim 5, wherein the hydraulic motor device has a relief valve.