JPS6030803A - Cross-bleed circuit in hydraulic drive device - Google Patents

Abstract

PURPOSE:To prevent restrictor valves from being heated, by connecting both ends of a hydraulic actuator through a pair of bypass passages, and as well by disposing a throttle valve and a check valve in each of the bypass passages. CONSTITUTION:Both ends of a hydraulic actuator 2 are connected together through a pair of bypass passages 19, 20 in which restrictor valves 21, 22 and check valves 23, 24 are respectively disposed with the check valves 23, 24 being directed in opposite directions with respect to each other. With this arrangement oil to be bled passes through either on of the restrictor valves 21, 22, selectively in dependence upon the driving direction of the hydraulic actuator 2. Accordingly, the restrictor valves 21, 22 may be prevented from being heated.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to a hydraulic drive device in which hydraulic pressure is selectively supplied fJ (fJ) to both ends of a hydraulic actuator by a servo valve, and in particular, the output This invention relates to a crossbleed circuit for reducing harmonic components of a waveform.

(b) Prior Art For example, in a testing machine for fatigue testing a test piece, in order to apply repeated loads to the test piece, as shown in Fig. 1, a hydraulic drive device has a hydraulic power source (1) and a hydraulic actuator (2). is commonly used. The hydraulic power source (1) includes a hydraulic pump (3) that supplies hydraulic pressure and a tank (4) that discharges hydraulic pressure.
), the hydraulic pump (3) is connected to the servo valve (6) by a supply channel (5). The tank (4) is connected to the servo valve (6) by a discharge channel (7).

The servo valve (6) is connected to both ends (2a), (2b) of the hydraulic actuator (2) by a pair of connecting channels (8), (9).
)It is connected to the.

The hydraulic pump (3) is driven by a motor (IO). Therefore, the hydraulic pressure or the supply flow path (5), its fission 1
servo valve (0) through the valve (11) and check valve (12).
). The servo valve (6) is switched by the input signal from the controller (14), and the hydraulic pressure is controlled by the connecting flow path (8).
), (!1) and are selectively supplied to both ends <2a), <2b) of the hydraulic actuator (2). When the hydraulic pressure is supplied (jt) to one end (2a) of the hydraulic actuator (2) through one contact QniAv path (8), the other end 1 (
The declension of 2b) is the other J&iii'cilljJ&<
9 >, servo valve (0), +, If output + (IJ to tank (・1) through path j (7) and its cooler (13)
I will be served. In contrast to 2j, the hydraulic pressure or the other contact i + ic flow path (
9) to the other end (2) of the hydraulic 1' gauge coater (2).
+1), the oil pressure at one end (2a>) or one connection 11!!41'8<8) should be discharged to the tank (+1). Ura j1-Ata f. 1” --
9 (2) is driven by hydraulic pressure and its piston (14
) is the i-+giL2 motion. With this, test 11.
;) 21!8 replies to No. 1, : Koju! −j got, =
y (The pieces were tested for fatigue.

However, when hydraulic pressure is selectively supplied to both ends (2a) and (2b) of the hydraulic antutor (2) and the piston (14) is reciprocated, surge pressure is generated. Due to the unstable phenomenon, harmonic components occur in the output waveform of the hydraulic actuator (2). Figure 2 shows the input waveform of the valve (6), and Figure 3 shows the output waveform of the hydraulic actuator (2). In order to reduce the harmonic components of this output waveform, both ends (2a) of the hydraulic actuator (2),
(2b) is connected by a /\Ibus channel (15), and a throttle valve (1G) is provided in this bypass channel (15). By this, the cross pulley 1 circuit (17) can be configured. When the hydraulic pressure is supplied to one end (2a) of the hydraulic actuator (2) through one of the connection channels (8),
Part of it!・Ibus channel (15) and its throttle valve (
1G) and is outputted to the other connecting flow path (9). When hydraulic pressure is supplied from the other connecting channel (9) to the other end (2b) of the hydraulic actuator (2), a part of it passes through the bypass channel (15) and its throttle valve (16);
One connection flow path (8) is outputted one by one. As is well known, this can reduce the harmonic components of the output waveform of the hydraulic actuator (2). FIG. 4 shows no harmonic component or reduced output l-shaping.

However, since i;ff, one connection L flow path (8)
Ura 1'', which is taken out from the bypass 1 city road (15) and its emblem 1 = (lG) 4i street, the other connection iii
7I to the throttle valve (Ifi) to pass through the throttle valve (16) of the + tile throttle valve (16).
-4X: 1. due to flow resistance of Jroura. Rib l” (IG
) There was a problem in which the government was unable to do so. Especially the throttle valve (1
6) Noura (11 or smaller, Leeho jF (Ii) switches at high speed 1i, 1-Nororo stand, I・1' bus!+!j
, Route (15) no Ura is I Ibas, Silk Route (15)'s)
i, f: I'm going to do abdominal exercise, and I'm going to do an exercise h'1f11! Road (8
).

There are times when (9) is not met. This noni,
・＼Heat is accumulated by the ura of Iba 1Ii47:'+(15) and aperture 9(
16) II sword size)? Shi, Danger 1; J'l in 1 Ka,
There was a problem.

(・＼) Purpose Therefore, the present invention provides a hydraulic 251 drive device as described above in which hydraulic pressure is selectively supplied to both ends of the hydraulic A2J-U'-6-Y by the "S"-E valve. , Sori I
This was done to prevent the throttle valve of the II Sfree-1 circuit from being overloaded.

(D) Configuration In this invention, both ii'2i of the hydraulic actuator are connected by a pair of bypass channels, and a throttle valve and a 1ψ stop valve are provided in each of the 7, 7, and 7 blood channels. The valve is characterized in that the check valves of each bypass flow path are arranged in opposite directions to each other.

(P) Example Embodiment III of the present invention will be explained below. FIG. 5 does not show an embodiment of the invention. ri ['Sub'J-1 time i? ? 1
(18) is - Neubus 1 City Road (19), (2(
]), and both ends (2a) of the hydraulic actuator (2)
, (2b) between these pair of bypass channels (19>,
(20>), and a calibration valve (21) is connected to each bypass flow path (19), (20).
, (22) A stop valve (23), (2.1) is provided. The check valves (23>, <24>) of the bypass channels (19), (20) are arranged in opposite directions.

In the hydraulic drive device 6 configured as IM as described above, the servo valve (6) is switched in response to an input signal from the controller 114, and the hydraulic pressure is returned through each of the connecting channels (8) and (9). , both ends (2a) of the hydraulic actuator (2), (2b
) is selectively [1: supplied. As a result, the piston (ll) of the hydraulic actuator (2) reciprocates, and the specimen is repeatedly subjected to a 1° 1:1 load, and the fatigue test is performed in the case shown in Figure 1. The same 1η.

Hydraulic pressure passes through one of the connection channels (8), and oil jI: of the actuator (2)! When lj is supplied to r1' cylinder 1 (2a), a part of it passes through one bypass flow path (19), its reverse valve (2: () and throttle valve (21), and flows to the other 4
Stone, ゛L i + Ii, 1iii (9) 1 no 1 is issued. On the other hand, the hydraulic pressure or the other contact Qj'e11fE path (9])
through the hydraulic actuator 1-yuator (2) (餠, V, i
(2b) when ((1, 1, sound), a part of it passes through the other bypass flow 11 old 20), its check valve (21I) and throttle valve (22), and passes through the -IJ- connection) no L flow path (
8) is given 1 no 1. This allows the hydraulic pressure to be
-, the harmonic components of the output waveform of the eta (2) are reduced.

This oil pressure (-1 sub-1 circuit is connected to one side R) ■ The hydraulic pressure output from flow path (8) to 4j) is output from one bypass flow path (
19) through the throttle valve (21) of the other connecting flow, path <9
) +Jl oil pressure is output from the other bypass flow path (2(
]) to pass through the throttle valve (22), the crest valve (21),
(22) is hardly heated. ”: T, Throttle valve (2
1), (22) is small and the servo valve (13) is switched at high speed, the bypass flow path (19),
The oil in (20) is... Ibas l+! 1 road (19>, (2
0) without stagnation in the connection channel (8).

(9) is discharged. Therefore, no heat is accumulated, and the lK11 degrees of the valves (21) and (22) do not exceed -4 degrees.

(To) Effects As explained above, this invention connects both ends of the hydraulic pressure -j'ri 1 shoyu J, - y with a pair of bypasses and ducts, and connects each end of the hydraulic pressure to each I and Ibasuura road. It has a simple structure with 7 valves and 11 reverse valves, which prevents the throttle valve from being heated and achieves the intended purpose.

[Brief explanation of the drawing]

Figure 1 is a hydraulic circuit diagram of a conventional hydraulic drive system, Figure 2 is a graph showing the input waveform of the servo valve in Figure 1, and Figure 3 is a graph showing the input waveform of the servo valve in Figure 1.
Graph showing the output waveform of the hydraulic actuator in Figure 1.
FIG. 1 is a graph showing an output wave 13 of a hydraulic actuator with a reduced harmonic component, and FIG. 5 is a hydraulic circuit diagram showing an embodiment of the present invention. (2)・・・・・・・・・・・・・・・・・・Hydraulic actuator (6)・・・・・・・・・・・・・・・・・・
・・・Servo valve (18)・・・・・・・・・・・・・・・
...Crossfleet circuit (19), (20)
”...Bypass flow path (21), (22
) ・・・−・・・ Throttle valve (23), (2=1
)・・・・・・・・・ Check valve patent applicant Masaaki Shimabara Corporation ('I: 1 (Ji agent NiimijiJ8 Department (Sl1 person) Shu l Figure 5 U

Claims (1)

[Claims] In a hydraulic drive system in which hydraulic pressure is selectively supplied to both p1"1, : of a hydraulic actuator by means of a one-point valve, 1) between both ends of the hydraulic actuator marked If. are connected by a bypass jAE path of one λ・j, and a check valve above the calibration valve is installed in each of the above 1:d bus flow paths; A cross pulley 1 circuit characterized by being arranged in the same direction.