CN1040159A - Can eliminate the hydraulic vibration device of piston skew automatically - Google Patents

Abstract

Can eliminate the hydraulic vibration device of piston skew automatically, owing to adopt the mode of mandatory assignment formula hydraulic vibration, therefore have simple in structure, dependable performance, vibration frequency changes advantages such as convenient, adopts again simultaneously and with pressure signal the piston that is vibrating is carried out position probing at any time, and feed back to the method for going in the control valve, overcome the phenomenon that piston skew takes place and clashes into cylinder cap in vibration processes, can be widely used in hydraulic vibration formula piling machine, various hydraulic vibration machineries such as hydraulic vibrating screen.

Description

The invention belongs to hydraulic vibration technology.

In the field of prior art, it is widely used in various vibrating machines as a forced distribution hydraulic vibrating device. It is convenient to change the vibrating frequency and has a simple structure. As shown in Figure 1, it consists of a three-position four-way switch Composed of oil cylinders driven by direction valves. When the spool of the three-position four-way reversing valve reciprocates near the zero position, the piston of the oil cylinder will reciprocate accordingly and generate vibration. When the reciprocating frequency of the three-position four-way reversing valve spool is changed, the oil cylinder The reciprocating frequency of the piston will also change accordingly, and the reciprocating frequency of the oil cylinder piston is the same as that of the spool of the three-position four-way reversing valve. However, there is a big problem with this vibration device, that is, due to the asymmetry of the flow rate of the three-position four-way reversing valve of the oil cylinder piston, errors in processing and assembly, and external interference, the oil cylinder piston will gradually deviate in the vibration process. At one end of the oil cylinder, the phenomenon that the oil cylinder piston hits the cylinder head will finally occur, so that the vibration cannot continue. The displacement curve of the cylinder piston is shown in Figure 2. With the increase of time t, the displacement s of the cylinder piston gradually deviates from the median line (indicated by the dotted line). Therefore this forced distribution type hydraulic vibrating device is difficult to use practically.

In order to overcome the above-mentioned problems, a hydraulic vibration device that can automatically eliminate the offset of the piston is developed, and the present invention is proposed.

The method adopted in the present invention is to detect the offset signal of the oil cylinder piston and feed it back to the three-position four-way reversing valve. Since the valve sleeve and the valve body can move relative to each other, the three-position four-way reversing valve The valve port formed between the spool and the valve sleeve is offset, which is formed in a cycle of the piston moving up and down, and the total flow through the port A and port B of the three-position four-way reversing valve is different when it moves downward and upward. , Automatically eliminate the offset of the piston.

Description of drawings:

Figure 1. Schematic diagram of the forced distribution hydraulic vibration device.

Fig. 2. Piston displacement curve of forced distribution hydraulic vibration device.

Figure 3. The input and output pressure curves of the hydraulic low-pass filter when the piston has no offset vibration.

Figure 4. The input and output pressure curves of the hydraulic low-pass filter when the piston is offset and vibrated.

Figure 5. Schematic diagram of hydraulic low-pass filter.

Fig. 6. Structural diagram of a hydraulic vibration device capable of automatically eliminating piston offset.

Fig. 7. Structural diagram of a hydraulic vibration device equipped with a two-position four-way hydraulic control reversing valve that can automatically eliminate piston offset.

The structure of the present invention is further described in conjunction with the accompanying drawings: the present invention includes the spool (11) of the three-position four-way reversing valve connected with the crank linkage mechanism, and the valve sleeve (12), which is provided with A, B, P, The valve body (10) of the O oil port is shown in Figure 6, the upper chamber of the oil cylinder communicates with the A port, the lower chamber communicates with the B port, the cylinder body (2), the piston (3), the valve sleeve (12) and the valve body (10 ] can perform relative movement; the valve body (10) also has a hole (13) communicating with the oil source (17), and a hole (9) communicating with the output end of the hydraulic low-pass filter (8); the piston ( 3) offset detector, which includes a groove (5) opened in the middle of the piston (3), and holes (4) communicated with the oil source (17) are respectively opened on the cylinder body (2), and are connected with the hydraulic low-pass The hole (6) communicated with the input end of the filter (8) and the hole (7) communicated with the fuel tank are composed of a hydraulic low-pass filter (8). When the piston (3) was vibrating normally without offset, the pressure curve of the input pressure (that is, the hole (6) place) of the hydraulic low-pass filter (8) is as shown in Figure 3 as a solid line. In one movement cycle of the piston, the input pressure of the hydraulic low-pass filter (8) is connected to the high pressure Ps and the return oil pressure P ₀ (P ₀ ≈ 0) at the same time, that is, t ₁ = t ₂ , through The output pressure Pc curve of the hydraulic low-pass filter (8) is shown in dotted line in Figure 3, Pc≈1/2 Ps. When the piston (3) deviates downward due to its own weight and other reasons, the pressure curve of the input pressure of the hydraulic low-pass filter (8) (that is, at the hole (6)) is shown by the solid line in Figure 4. The time _t1 when connecting to the high pressure Ps is greater than the time _t2 when connecting to the low pressure _P0 . At this time, the output pressure Pc of the hydraulic low-pass filter (8) is shown by the dotted line in Figure 4, Pc> 1/2 Ps, otherwise when the piston (3 ] When upward displacement occurs during the vibration process, the output pressure Pc of the hydraulic low-pass filter (8) < 1/2 Ps. That is to say, according to whether the output pressure Pc of the hydraulic low-pass filter (8) is greater than, less than or equal to 1/2 Ps and the size, it can be judged whether the piston (3) is downward, upward or without offset and the size of the offset . The three-position four-way reversing valve is different from the general ones. The valve sleeve (12) and the valve body (10) can move relative to each other, and is controlled by the output pressure Pc of the hydraulic low-pass filter (8). The valve sleeve (12) The upper end passes through the hole (9) on the valve body (10), and the pressure area controlled by the output pressure Pc of the hydraulic low-pass filter (8) is _A1 , and the lower end of the valve sleeve (12) passes through the hole (10) on the valve body (10). 13) The pressure area connected to the oil source is A ₂ , generally A ₁ ≈ 2A ₂ . When the piston (3) has no offset vibration, the upper and lower oil pressures on the valve sleeve (12) are Pc·A ₁ and Ps·A ₂ respectively. Since Pc=1/2 Ps at this time, the upper and lower oil pressures The force is equal, the valve sleeve (12) is in the neutral position, when the piston (3) gradually shifts downward during the vibration process, the output pressure Pc of the hydraulic low-pass filter (8)> 1/2 Ps, at this time the valve sleeve 〔12〕The upper and lower oil pressures are unequal, that is, Pc·A ₁ >Ps·A ₂ , so that the valve sleeve 〔14〕 moves downward so that it passes through the valve port B in one vibration cycle of the piston 〔3〕. The total flow is greater than the total flow through the valve port A, so that the piston (3) gradually moves upward during the vibration process, eliminating the piston offset. Conversely, when the piston (3) gradually shifts upward during the vibration process, at this time Pc<1/2 Ps, Pc·A ₁ <Ps·A ₂ , the valve sleeve moves upward, so that a vibration of the piston (3) During the cycle, the total flow through the valve port A is greater than the total flow through the valve port B, so that the piston (3) gradually moves downward during the vibration process, eliminating the piston offset.

In order to eliminate pressure pulsation, an accumulator (16) is equipped at the outlet of the oil source (17).

Drive crank (17) to rotate with electric motor or oil motor, drive spool (13) to move up and down by connecting rod (16), change the rotating speed of electric motor or oil motor, just can change the vibration frequency of piston (3).

Vibrated object (1) can be fixed with cylinder block (2), also can be fixed with piston rod and piston (3) as required.

Hydraulic low-pass filter (8) is made up of damping hole and liquid capacity, and as shown in Figure 5, changing the liquid resistance of damping hole and the size of liquid capacity can obtain the transition process of the optimum deviation correction of piston (3). Wherein damping hole can directly form damping hole with hole (6) on the cylinder block (2) or hole (7), hole (4) dwindling their diameter. The liquid capacity can also be replaced by an accumulator except that the liquid capacity directly connected to the pipeline can be used.

Another embodiment of the present invention is: a three-position four-way reversing valve composed of a valve core (11), a valve sleeve (12) and a valve body (10) can be used as a pilot stage to control a two-position four-way hydraulic control reversing valve. Directional valve (18), as shown in Figure 7, controls the vibration of piston (3) through the two-position four-way hydraulically controlled reversing valve (18). The A' port of [18] is connected, the lower chamber of the oil cylinder is connected with the B' port of the two-position four-way hydraulic control reversing valve (18), and the A and B ports of the valve body (10) are connected with the two-position four-way hydraulic control reversing valve respectively. The hydraulic control port C and D port of valve (18) are communicated. This structure is especially suitable for high-power hydraulic vibrators.

The effect of the present invention is: due to the adoption of forced flow distribution hydraulic vibration, it has the advantages of simple structure, reliable performance, and convenient vibration frequency change; at the same time, the pressure signal is used to detect the position of the vibrating piston at any time, and it is fed back to The method of removing the control valve overcomes the phenomenon that the piston deviates and hits the cylinder head during the vibration process; it can be widely used in various hydraulic vibration machines such as hydraulic vibration pile drivers and hydraulic vibrating screens.

Claims (2)

1, a kind of hydraulic vibration device that can eliminate the piston skew automatically, it comprises the spool [11] of the three position four-way directional control valve that is connected with toggle, valve pocket [12], have the valve body [10] of A, B, P, O hydraulic fluid port, the cylinder body [2] that oil cylinder epicoele and A mouth connected sum oil cylinder cavity of resorption are communicated with the B mouth, piston [3], feature of the present invention is: can do relative motion between valve pocket [12] and the valve body [10]; Valve body [10] also has the hole [13] that is communicated with oil sources [17], the hole [9] that is communicated with hydraulic low-pass filter [8] output; The offset detector of piston [3], it comprises the groove [5] that is had by piston [3] middle part, have the hole [4] that is communicated with oil sources [17] on the cylinder body [2], hole [6] that is communicated with hydraulic low-pass filter [8] input and the hole [7] that is communicated with fuel tank and hydraulic low-pass filter [8] are formed.

2, a kind of hydraulic vibration device that can eliminate the piston skew automatically, it comprises the spool (11) of the three position four-way directional control valve that is connected with toggle, valve pocket (12), have the valve body (10) of A, B, P, O hydraulic fluid port, cylinder body (2), piston (3) that oil cylinder epicoele and the A ' mouth connected sum oil cylinder cavity of resorption of two-position four-way pilot operated directional control valve (18) are communicated with the B ' mouth of two-position four-way pilot operated directional control valve (18), feature of the present invention is: can do relative motion between valve pocket (12) and the valve body (10); Valve body (10) also has the hole (13) that is communicated with oil sources (17); The hole (9) that is communicated with hydraulic low-pass filter (8) output; The offset detector of piston (3), it comprises the groove (5) that is had by piston (3) middle part, have the hole (4) that is communicated with oil sources (17) on the cylinder body (2), with the hole (6) that hydraulic low-pass filter (8) input is communicated with, the hole that is communicated with fuel tank (7) and hydraulic low-pass filter (8) are formed; Valve body (10) A, B mouth are communicated with hydraulic control mouth C, the D mouth of two-position four-way pilot operated directional control valve (18) respectively.

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