KR20130129136A - Damping device - Google Patents

Abstract

The present invention relates to a damping device comprising a first work connection unit for the connection of a consumer to be damped (especially, a lift cylinder) in a movable operation machine and a hydraulic accumulator connection unit for the connection of a hydraulic accumulator. Furthermore, a main valve has at least one first conversion position and at least one second conversion position. The connection in the first conversion position is only opened from the first work connection unit (& consumer) to the hydraulic accumulator connection unit. Thus, the damping is stopped. The connection in the second conversion position is bilaterally opened. Thus, the damping is operated. Furthermore, a control valve is provided. The main valve can be converted to the second conversion position in a hydraulic method by the control valve and the damping can be operated or stopped. Furthermore, the damping device according to the present invention includes a discharge valve. The discharge valve is connected to the control valve, the first work connection unit (& consumer), and the hydraulic accumulator connection unit in order for the hydraulic accumulator to be discharged by the discharge valve according to the operation of the control valve when the pressure of the hydraulic accumulator connection unit is greater than the pressure of the first work connection unit (& consumer). When the hydraulic accumulator and the consumer are connected, the discharge impact is prevented thereby because excessively higher pressure is controlled after being firstly reduced according to the hydraulic accumulator. The discharge or decompression is performed as the discharge valve opens the connection relative to a discharge connection unit or a tank connection unit from the hydraulic accumulator connection unit of the damping device.

Description

Damping Device {DAMPING DEVICE}

The invention relates to a damping device according to the preamble of claim 1.

This damping device is used, for example, as a stabilization module in wheel loaders in order to damp the longitudinal vibrations occurring during travel. For this purpose, the loading shovel is first lifted by the pump and the lift cylinder, and the pressure chamber under the load pressure of the lift cylinder is separated from the pump by a control valve. The pressure chamber under load pressure during the loading operation of the wheel loader is connected to a hydraulic accumulator charged via a stabilization module to damp longitudinal vibrations.

This damping device is disclosed in publication EP 1 407 086 B1, which damping device comprises a main valve (also referred to as a control valve), in which the pressure valve of the lift cylinder is switched by the main valve when the control valve is switched. The connection between and the hydraulic accumulator is opened. By the regulating valve, the moment at which damping should be started is determined.

Upon activation of damping by opening the main valve, it is not desirable in such damping devices if the pressure of the previously charged hydraulic accumulator is higher than the pressure in the pressure chamber of the lift cylinder, which is generally determined by the weight of the shovel and its filling. Not discharging shock occurs.

An object of the present invention is to provide a damping device in which the discharging shock is prevented when the damping device is activated.

The problem is solved by a damping device comprising the features of claim 1.

The damping device according to the invention comprises a first working connection for the connection of a consumer (especially a lift cylinder) to be damped of a mobile work machine (especially a wheel loader) and an accumulator connection for the connection of a hydraulic accumulator. The main valve also has at least one first and second switching position. In the first switching position the connection is opened only from the first working connection (and consumer) to the accumulator connection (and hydraulic accumulator). The damping is thus stopped. In the second switching position the connection is open in both directions. Damping is thus activated. In addition, a regulating valve is provided, by which the main valve can be hydraulically switched to the second switching position. That is, damping can be activated and stopped again. The damping device according to the invention also comprises a discharging valve, wherein the discharging valve is a regulating valve when the pressure at the accumulator connection (and hydraulic accumulator) is greater than the pressure at the first working connection (and consumer). In accordance with the operation of the hydraulic accumulator is connected to the control valve, the first working connection (and consumer) and the accumulator connection so that it can be partially discharged by the discharge valve. This prevents discharging shocks when the hydraulic accumulator and consumer are connected, because in the case of hydraulic accumulators, too high pressure is first reduced before being adjusted. Discharge or depressurization is achieved in particular by the discharging valve opening the connection from the accumulator connection of the damping device to the discharging connection or the tank connection.

Other preferred embodiments of the invention are set forth in the dependent claims.

It is particularly preferred that the main valve can only be switched to the second switching position by the regulating valve only after the end of the partial discharging of the hydraulic accumulator. This further minimizes discharging shock.

In a particularly preferred embodiment, upon operation of the regulating valve, the discharging valve is first operated until the pressure at the first working connection (and consumer) is less than the pre-set pressure difference than the pressure at the accumulator connection (and in the accumulator). Keep open.

Preferably the valve body of the discharging valve can be hydraulically loaded on the one hand by means of the pressure of the accumulator connection (and in the hydraulic accumulator) via the regulating valve and on the other hand the first working connection (and the consumer). Under load The preset pressure differential (eg about 10 bar) is defined by a prestressed spring acting on the valve body. As a result, the switching timing of the discharge valve is specifically implemented. The spring is preferably adjustable.

Preferably the valve body of the discharging valve can be moved to an open position for opening of the discharging line by the pressure of the accumulator connection while the control valve is open. In addition, the valve body of the discharging valve can be moved to the closed position by the spring formed as the compression spring and the pressure of the first working connection. The closed position is used to interrupt the discharging line at least in the direction of the tank connection from the accumulator connection.

In a first preferred variant, which is technically simple, the discharging valve is a leak-free 2 / 2-way seat valve.

It is preferred that a flow restrictor be arranged between the output of the regulating valve and the control surface acting in the opening direction of the main valve, the flow restrictor always being predetermined from the regulating valve to the control surface irrespective of the pressure and viscosity of the control pressure medium. Since the amount of control pressure medium is passed, opening of the main valve and starting damping always require a predetermined time (eg 2 seconds).

It is preferred that the main valve has a shut off position, in which case the first switch position is arranged between the shut off position and the second switch position. Therefore, the pressure compensation from the higher pressure working connection to the lower pressure accumulator connection may be achieved since the first switching position must be passed upon opening the main valve, in which case the flow restrictor uses a predetermined time for this. .

In a second preferred variant the discharging valve is a 5 / 2-way valve. In this case, the connection between the output of the control valve and the control surface acting in the opening direction of the main valve is interrupted by the open position of the valve body of the valve, and at the same time the control surface is discharged. This ensures that if the discharging valve is still discharged, the main valve is not open for damping. The temporal continuity of two states, therefore, "discharging" and "damping" is ensured.

In a preferred refinement of the second variant, a throttle device is provided between the 5 / 2-distribution valve and the control surface acting in the opening direction of the main valve. This dampens and delays the opening and closing of the main valve.

In a preferred variant of the damping device according to the invention, the consumer, which can be damped by the damping device, acts as a double, in which case the damping device is for the connection of the tank and the consumer (especially the ring chamber of the lift cylinder). It has a 2nd working connection part. The connection between the tank connection and the second working connection is interrupted at the first switching position of the main valve, and the connection is opened in both directions at the second switching position of the main valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 shows a part of a hydraulic circuit of a wheel loader incorporating a first embodiment of a damping device according to the invention.
2 shows a part of a hydraulic circuit of a wheel loader comprising a second embodiment of a damping device according to the invention.
3 is a cross-sectional view of the discharging valve of the first embodiment according to FIG. 1.
4 is a first cross-sectional view of the discharging valve of the second embodiment according to FIG. 2.
5 is a second cross-sectional view of the discharging valve of the second embodiment according to FIGS. 2 and 4.

1 shows a part of a hydraulic circuit of a wheel loader. The wheel loader comprises two lift cylinders 1 working together, each of which is formed as a differential cylinder and is used to lift a shovel (not shown) of the wheel loader. The lift cylinder 1 comprises one base chamber 2 and a ring chamber 4, in which case the two base chambers 2 pass through the first work line 6 and the two ring chambers ( 4) is connected to the control block 8 of the wheel loader via the second work line 10. The control block controls the pressure medium supply of the two lift cylinders 1 and the lift movement of the shovel. The wheel loader also includes a tank 12.

In particular, the damping device 14 according to the invention is applied to a first work line 6 which acts as a lifting force during high speed operation of the wheel loader (for example 6 km / h or more) and especially when the shovel is charged. The hydraulic accumulator 16 can be connected via. To this end, the damping device 14 has a first working connection A and a second working connection B, through which the damping device is connected to two base chambers 2, The damping device is connected to two ring chambers 4 via a connection. The damping device also has an accumulator connection (X2) and a tank connection (T), through which the damping device is connected to a hydraulic accumulator (16), and through the tank connection to the tank (12). Connected.

The damping device 14 has a main valve 18 formed as a 4 / 4-way valve, which is connected to two working connections A, B on the one hand and to the accumulator connection (on the other hand). X2) and the tank connection T. The valve body (not shown) of the main valve 18 has a first switching position a in which the connection between the second working connection B and the tank connection T is interrupted, while The connection of the accumulator connection X2 and the first working connection A is provided by a check valve which is prestressed. In addition, the main valve has a blocking position (b), in which all four connections (A, B, X2, P) are blocked relative to one another. In the discharging position c of the main valve 18, the accumulator connection X2 is discharged to the tank 12 via the throttle and the tank connection T, while the two working connections A, B are Is blocked.

The first switching position (a), the blocking position (b) and the discharging position (c) may continue with each other. In addition, the main valve 18 has a second switching position d, in which the two base chambers 2 pass through the first working connection A and the accumulator connection X2. While connected to 16, the two ring chambers 4 are discharged to the tank 12 via the second working connection B. In case the longitudinal vibration of the wheel loader by the shovel should be damped or prevented, the main valve 18 is switched to the second switching position d.

The valve body of the main valve 18 can be moved in the open direction by the control line 20 and the control face 22 (not shown in detail) according to the regulating valve 26, while the valve body is controlled by the control line 26. 28 and the control face 30 can be moved in the closing direction. Two control lines 20, 28 are connected to the accumulator connection X2. In addition, the spring 24 acts in the opening direction of the main valve 18 and the spring 32 acts in the closing direction. The force of the spring 24 acting in the open direction may correspond to 120 bar, while the force of the spring 32 acting in the closed direction may correspond to 10 bar. The control face 22 acting in the open direction can have a diameter of 20 mm, while the control face 30 acting in the closed direction can have a diameter of 4 mm.

The predetermined accumulator of the hydraulic accumulator 16 formed by the wheel loader's (not shown) pump through the control block 8, the first working connection A and the first switching position of the main valve 18. At the pressure, the valve body of the main valve 18 is moved to the shut off position b.

The regulating valve 26 used to shut off or open the control line 20 is formed as a 3 / 2-way valve. The regulating valve 26 discharges the control face 22 of the main valve 18 which acts in the opening direction in the basic position 0 which is prestressed by the spring to the tank connection T. In the switching position e where the current is supplied, the regulating valve 26 applies the pressure of the hydraulic accumulator 16 to the control surface 22, so that the main valve 18 is switched to the second switching position d. And damping of the shovel can be activated.

A flow restrictor 34 is provided in the control line 20 between the regulating valve 26 and the control face 22 of the main valve 18, which is independent of the viscosity and pressure of the control pressure medium. Pass a limited amount of pressure medium. This allows the valve body of the main valve 18 to pass through the first switching position a for a predetermined duration (eg 2 seconds) when moving from the blocking position b to the second switching position d. Thereby, it is ensured that discharging by the check valve of the 1st switching position A is possible when the pressure of the 1st working connection part A is higher than the pressure of accumulator connection part X2.

According to the invention, the discharging line 36 is arranged between the accumulator connection X2 and the tank connection T. A discharging valve 38 is arranged in the discharging line 36, which is formed as a 2 / 2-way-seat valve. The valve body 40 (shown in FIG. 3) of the valve can take one closed position f and a plurality of open positions g. The discharge valve 38 has a pressure accumulator connection part X2 at the input part and a tank connection part T at the output part. The valve body 40 is moved in the closing direction by the compression spring 42 and the work connecting portion A acting in the closing direction, while the valve body 40 is moved in the opening direction by the control connecting portion Y1. The control connection Y1 is connected to the control line 20 between the regulating valve 26 and the flow restrictor 34.

FIG. 2 shows a part of the hydraulic circuit of the wheel loader according to FIG. 1 comprising a second embodiment of a damping device 114 according to the invention. Substantially two differences from the first embodiment according to FIG. 1 are provided on the one hand with a 5 / 2-seat-direction valve as the discharging valve 138 and on the other hand with a flow restriction on the control line 20. The throttle device 134 is provided instead of the machine 34.

In the two embodiments described above, the actuation of damping is effected by the regulating valve 26. This can be done automatically upon exceeding the lowest speed (eg 6 km / h). When the pressure of the working connection A is less than the pressure of the accumulator connection X2 by less than the pressure difference preset by the spring 42, the discharging valves 38; 138 of the two embodiments are closed. Stay at position (f). The pressure of the accumulator connection X2 is transmitted to the relatively large control face 22 by the open control valve 26 and the flow restrictor 34 or the throttle device 134. On interaction with the spring 24 the main valve 18 opens to the second switching position d. Alternatively, when the pressure in the base chamber 2 of the first working connection A and the lift cylinder 1 is significantly lower than the pressure of the accumulator connection X2 and the hydraulic accumulator 16, the regulating valve 26. The pressure of the hydraulic accumulator 16 is reduced according to the invention after the opening of the valve and before the opening of the main valve 18. For this purpose it is sufficient to delay the opening of the main valve 18 in the first embodiment according to FIG. 1, which opening is achieved by the flow restrictor 34. Before the flow restrictor opens the main valve 18, the discharging valve 38 according to FIG. 1 is opened because the pressure of the control connection Y1 is controlled by more than the equivalent load of the compression spring 42. It is because it is higher than the pressure of the connection part A. FIG. In the second embodiment according to FIG. 2, the opening of the main valve 18 is necessarily inhibited until the discharging valve 138 ends the discharging process and returns from the open position g to the closed position f. . The premature opening of the main valve 18 is the main valve until the discharging valve 138 is in its open position (g) until discharging is terminated and the discharging valve 138 returns to the closed position (f). The control surface 22 of 18 is inhibited by discharging to the tank connection part T by the control connection part Y2. At that time, since the control line 20 is released, the main valve 18 can be opened.

3 shows a cross-sectional view of the discharging valve 38 of the first embodiment of the damping device 14 according to the invention according to FIG. 1. Within the housing 44 the valve body 40 can be moved along its longitudinal axis 46. The connection from the accumulator connection X2 to the tank connection T can be opened or blocked by the valve seat 48 and the conical section 50 formed in the housing 44. Thus the discharging of the hydraulic accumulator 16 (see FIG. 1) is started or terminated. 3 shows the valve body 40 in the closed position f (see FIG. 1). The valve body 40 is moved to the closed position f in particular by the pressure of the compression spring 42 and the first working connection A. The compression spring and pressure act on the end section 52 of the valve body 40. The end section 42 is disposed in the pressure chamber, which is limited by a closure 54 which is turned into the housing 44 and connected to the first working connection A via the bore star 60. do. The compression spring 42, which contacts the end section 52 of the valve body 40 via the spacer 53, is supported by the closure 54.

The pressure of the accumulator connection portion X2 also acts in the closing direction by the ring-shaped differential surface 55 slightly. The control connection Y1 provided on the end of the housing 44 acts against the pressure in the open direction, and the pressure of the control connection causes the conical section 50 to lift from the valve seat 48 over the end face 56. It can be raised and the discharging valve is opened for discharging the hydraulic accumulator 16 (see FIG. 1). The accumulator connection X2 is arranged in the region of the conical section 50 and the differential surface 55 when viewed along the longitudinal axis 46, while the tank connection T is conical section 50 and the end surface. Disposed between 56.

The valve body 40 is supported and guided in the housing 44 directly between the end face 56 and the tank connection T on the one hand and between the differential face 55 and the end section 52 on the other hand. It is supported and guided by the guide bush 58. The guide bush 58 is supported by the closure 54 and limits the pressure chamber connected to the first working connection A. The guide bush 58 also includes a seal.

4 and 5 show the discharging valve 138 of the second embodiment of the damping device 114 according to the invention in two different cross sectional views. The discharging valve 138-unlike the housing 44 of the first embodiment-comprises a housing 144 extending to the left (in FIGS. 4 and 5) and within the housing-the valve body of the first embodiment ( Unlike 40, an elongated valve body 140 is movably received along the longitudinal axis 46. The discharging valve of FIGS. 4 and 5 (right part) substantially corresponds to the discharging valve 38 according to FIG. 3. A first working connection A connected to the pressure chamber formed inside the closure 54 via the radial bore star 60, shown in FIG. 5, is also provided to the discharging valve 38 according to FIG. 3.

Unlike the discharging valve 38 according to FIG. 3, the discharging valve 138 comprises another tank connection T1 (see FIG. 5), a control connection Y2 and a control connection Y1 (see FIG. 4). The pressure of the control connection Y1 is transmitted to the end face 56 of the valve body 140 via the channel 146, and a pressure chamber is formed around the valve body, and the pressure chamber has an end side closure ( 48).

In FIG. 5, the check valve 150 is disposed between the tank connection T1 and the valve body 140, and the opening direction of the valve is directed from the valve body 140 to the tank connection T1 (FIG. 5). 2).

4 and 5, the discharging valve 138 according to the second embodiment is shown in the closed position f (see FIG. 2), in which the accumulator connection X2 and the tank connection T; Discharging line 36 (see FIG. 2) connected to the < RTI ID = 0.0 > The control line 20 connected to the control connections Y1 and Y2 is opened. By increasing the control pressure of the control connecting portion Y1 and / or decreasing the control pressure of the first working connecting portion A, the valve body 140 (in FIGS. 4 and 5) is moved to the right and in the open position g (FIG. 2). Reference). In this case, discharging is made from the accumulator connection part X2 to the tank connection part T, and the control connection part Y2 is discharged to the tank connection part T1 by the open check valve 150. FIG. This closes the main valve 18 (refer FIG. 2), and in this case, the pressure of the hydraulic accumulator 16 applied to the control connection part Y1 is interrupted | blocked. Thus, before the main valve 18 (see FIG. 2) is opened, the discharging of the hydraulic accumulator 16 is ensured.

Unlike the illustrated embodiment of the discharging valves 38; 138, the discharging valves together with a few or all other parts and valves of the damping device 14; 114 according to the invention in a common housing. Can be integrated.

A damping device is disclosed having a first work connection for the connection of a consumer to be damped of a mobile work machine and an accumulator connection for the connection of a hydraulic accumulator. The main valve also has at least one first and second switching position. In the first switching position the connection opens only from the first working connection to the accumulator connection. The damping is thus stopped. In the second switching position the connection is opened in both directions. Damping is thus activated. In addition, a regulating valve is provided, by which the main valve can be hydraulically switched to the second switching position, ie the damping can be activated and stopped again. The damping device according to the invention comprises a discharging valve, wherein the valve accumulates in part by the discharging valve in accordance with the operation of the regulating valve when the pressure of the accumulator connection is greater than the pressure of the first working connection. To the control valve, the first working connection and the accumulator connection to be discharged. Therefore, the discharging shock is prevented when the hydraulic accumulator and the consumer are connected, because in the case of the hydraulic accumulator, too high pressure is first reduced and adjusted.

1 lift cylinder
2 base chamber
4 ring chamber
6 first working line
8 control blocks
10 second working line
12 tank
14; 114 damping device
16 hydraulic accumulator
18 main valve
20 control lines
22 control plane
24 springs
26 regulating valve
28 control lines
30 control faces
32 springs
34 flow limiter
36 discharging line
38; 138 Discharge Valve
40; 140 valve body
42; 142 compression spring
44; 144 housing
46 vertical axis
48 valve seat
50 conical sections
53 spacer
54 closures
55 differential plane
56 end face
58 guide bush
60 bore star
134 throttle device
146 channels
148 closure
150 check valve
A first working connection, control connection
B second working connection
X1 control connection
X2 accumulator connection
Y1 control connection
Y2 control connection
T tank connection
T1 tank connection
0 default position
a first switching position
b blocking position
c discharging position
d second switching position
e switching position
f closed position
g open position

Claims (11)

Damping device 14 with a accumulator connection X2 and a control valve 26 for the connection of the hydraulic accumulator 16 and the first working connection A for the connection of the consumer 1 to be damped of the mobile work machine. 114, the main valve 18 has at least one first switching position a and a second switching position d, in which connection is made to the first working connection A; ) Is opened only to the accumulator connection (X2), in the second switching position (d) the connection is opened in both directions, by means of the regulating valve the main valve (18) is hydraulically operated in the second switching position ( In the damping device that can be switched to d),
The damping device (14; 114) comprises a discharging valve (38; 138), wherein the discharging valve is provided when the pressure of the accumulator connection (X2) is greater than the pressure of the first working connection (A). The regulating valve 26 and the first working connection A so that the hydraulic accumulator 16 can be discharged by the discharging valve 38; 138 according to the operation of the regulating valve 26. And a accumulator connection (X2). Damping according to claim 1, characterized in that after discharge of the hydraulic accumulator (16) the main valve (18) can be switched to the second switching position (d) by the regulating valve (26). Device. 3. The discharge valve (38; 138) according to claim 1 or 2, wherein the discharging valve (38; 138) causes the shaft of the first working connection (A) to be less than a predetermined pressure difference depending on the operation of the regulating valve (26). The damping device, characterized in that it is opened until it is less than the pressure of the pressure-pressure connection (X2). 4. The valve body (40; 140) of the discharging valve (38; 138) can be hydraulically loaded by the pressure of the accumulator connection (X2) through the control valve (26). The valve body 40; 140 may be loaded by the pressure of the first working connection A, and the preset pressure difference may be a prestressed spring acting on the valve body 40; Damping device, characterized in that defined by 42; 5. The valve body (40) according to claim 4, wherein the valve body (40; 140) can be moved to the open position (g) by the pressure of the accumulator connection (X2) with the regulating valve (26) open, Damping device, characterized in that the valve body (40; 140) can be moved to the closed position (f) by the spring formed as 42; 142 and the pressure of the first working connection (A). 6. The damping device according to claim 1, wherein the discharging valve is a 2 / 2-way seat valve. 7. Damping device according to claim 6, characterized in that a flow restrictor (34) is arranged between the output of the control valve (26) and the control surface (22) acting in the opening direction of the main valve (18). . 8. The main valve (18) according to claim 7, wherein the main valve (18) has a cutoff position (b), and the first switchover position (a) is arranged between the cutoff position (b) and the second switchover position (d). Damping device characterized in that. 6. The discharge valve (138) according to claim 5, wherein the discharging valve (138) is a 5 / 2-way valve, and the output of the regulating valve (26) and the main by the open position (g) of the valve body (140) of the valve. Damping device, characterized in that the connection with the control surface (22) acting in the opening direction of the valve (18) can be interrupted and at the same time the control surface (22) can be discharged. 10. Damping device according to claim 9, characterized in that a throttle device (134) is arranged between the 5 / 2-way valve and the control face (22). 11. The consumer (1) according to any one of claims 1 to 10, wherein the consumer (1) acts in dual, and the damping device has a tank connection (T), and a second working connection for connection of the consumer (1). B), wherein the connection of the second working connection B and the tank connection T is interrupted at the first switching position a, and the connection is opened in both directions at the second switching position d. Damping device, characterized in that.

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