JP2012002272A - Hydraulic cylinder and hydraulic drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a larger cylinder output when a hydraulic cylinder is extended, effectively accelerate drive in a cylinder contracting direction when the cylinder is contracted, and recover energy using a second cylinder.SOLUTION: The cylinder includes large and small cylinder chambers, and a body is integrated with a rod bar. The extension and contraction of the cylinder is controlled by a first cylinder 61. Oil of a second cylinder 71 moves in a head-side chamber 76 and rod-side chamber 72 via a solenoid valve 4. The excess and deficiency is transferred via a T port of the solenoid valve 4. When a load is imposed on a first head-side chamber 66 during extension to increase the pressure, the solenoid valve 4 is energized in response to a signal from a pressure switch 7, and pressure oil comes out of an A port and enters the second head-side chamber 76 to extend and pressurize the cylinder. Two cylinders are used for pressurization, thereby increasing output. Only the first cylinder 61 is contracted, thereby increasing the speed.

Description

  The present invention relates to a hydraulic cylinder for driving a press machine or the like and a hydraulic drive device using the hydraulic cylinder.

  Conventionally, many hydraulic cylinders are used to reciprocate a press and other various machines. The higher the expansion / contraction speed of the hydraulic cylinder, the higher the working efficiency. In general, the expansion / contraction speed of the hydraulic cylinder is determined by the discharge amount and discharge pressure of the hydraulic pump. Therefore, in order to obtain a higher expansion / contraction speed with a limited discharge amount and discharge pressure of the pump, it is necessary to increase the expansion / contraction speed when there is no load and when the load is small.

  For this purpose, a cylinder main body surrounding the first cylinder chamber and the first cylinder chamber so as to form a first head side chamber and a first rod side chamber by dividing the first cylinder chamber in the axial direction thereof. A first piston portion having a first piston portion, and a first piston rod having a first rod portion extending from the first piston portion toward the first rod side chamber and projecting to the outside of the cylinder body. Has a second cylinder chamber extending in a direction parallel to the axial direction of the first cylinder chamber, and the cylinder body extends from the first head side chamber side to the first rod side chamber side in the first cylinder chamber. The second piston rod has an extending second piston rod, and an end of the second piston rod constitutes a second piston portion to be loaded into the second cylinder chamber, and the second piston portion is in the second cylinder chamber. The space on the distal end side of the rod portion with respect to the second piston portion is sealed to form a second head side chamber, and the cylinder body or the first piston rod is disposed outside the hydraulic cylinder inside the second head side chamber. A hydraulic cylinder having a head-side oil passage for communicating with the cylinder is known (see Patent Document 1).

JP 2008-51194 A (paragraphs [0006] [0007])

  However, in the above invention, since only the piston (second piston portion 32 in Patent Document 1) having a smaller diameter than that at the time of expansion is pressurized, it is difficult to obtain a large cylinder output. Further, the structure of the hydraulic cylinder is complicated, the manufacturing cost is expensive, and the hydraulic drive control device is complicated.

  In view of such circumstances, the present invention can obtain a larger cylinder output when there is a certain load or more during expansion, and efficiently increases the drive of the hydraulic cylinder when there is no load, when the load is small, and when contracting. It aims at providing the technology of the simple structure for speeding up.

  Therefore, the present inventor has made intensive studies in view of the disadvantages found in the prior art. As a result, the first cylinder (1) (68) is closed and the other end (69) is formed with a through hole (80). 61), a first port (63) is drilled on one end side, a second port (64) is drilled on the other end side, a through hole (80) is formed on one end (78), and the other end (79). ), A second through hole (82) is formed, and a third port (73) is formed on the one end side of the second cylinder (71) having an inner diameter larger than that of the first cylinder. The 4th port (74) is drilled and the 1st rod (67) which penetrated the through-hole (80) is slidably contacted with the 1st piston (65) which slidably contacts with the inner peripheral wall of a 1st cylinder, and the inner peripheral wall of a 2nd cylinder. The second piston (75) is connected to the other end (79) side surface of the second piston (75). (77) is focusing on that it can solve the problem by the hydraulic cylinder (6) passing through the second through-hole, thereby completing the present invention based on this finding.

  The hydraulic drive apparatus according to the present invention includes a hydraulic cylinder (6), a hydraulic pump (1), and a hydraulic circuit (21) that guides the oil discharged from the hydraulic pump to the hydraulic cylinder to expand and contract the hydraulic cylinder. The hydraulic circuit (13) includes an oil supply to a first head side chamber (66) formed between the first piston (65) and one end (68) of the first cylinder. The oil is discharged from the first rod side chamber (62) formed between the first piston and the other end (69) of the first cylinder to the outside of the hydraulic cylinder, and the second piston (75) and the second piston Oil discharged from the second rod side chamber (72) formed between the other end (79) of the cylinder to the outside of the hydraulic cylinder is formed between the second piston and one end (78) of the second cylinder. Supplied to the second head side chamber (76) An oil passage for extension driving to be joined to the first rod side chamber, oil is supplied from the first head side chamber to the outside of the hydraulic cylinder, and oil discharged from the second head side chamber is discharged to the second rod side chamber. And an oil passage for contraction driving led to.

  The extension drive oil passage preferably supplies the hydraulic pump discharge oil to the second head side chamber (76) when the internal pressure of the first head side oil passage (6A) communicating with the first head side chamber exceeds a predetermined value. . Thus, when there is a certain load or more during expansion, oil is supplied to the second cylinder having a larger inner diameter, so that a larger cylinder output can be obtained.

  The extension drive oil passage preferably supplies the hydraulic pump discharge oil to the second head side chamber (76) when a sensor (7K) attached to a predetermined position of the first cylinder senses the first piston. As a result, it is understood that a larger output is required by sensing the first piston, and oil is supplied to the second cylinder having a larger inner diameter, so that it is larger than when there is a certain load or more during expansion. Cylinder output can be obtained. Further, when the hydraulic drive device is stopped, the first and second rods of the hydraulic cylinder can be stopped more steadily by the operation of the pilot check valve 5.

  The hydraulic circuit has a check valve that allows oil to flow from the second rod side oil passage (7B) communicating with the second rod side chamber to the second head side oil passage (7A) communicating with the second head side chamber. It is preferable to provide. Thus, even when the inner diameter of the second cylinder is larger, the speed when the hydraulic cylinder is extended can be improved.

  The contraction drive oil passage cancels the one-way passage of the check valve by the pressure of the oil in the first rod side chamber or the first rod side oil passage (6B), and the second rod side from the second head side oil passage. It is preferable to allow the flow of oil into the oil passage. As a result, even when the inner diameter of the second cylinder is larger, the speed when the hydraulic cylinder contracts can be improved.

  According to the hydraulic cylinder of the present invention, the first cylinder and the second cylinder having a larger inner diameter are connected in series, and the first piston that is in sliding contact with the inner peripheral wall of the first cylinder and the inner peripheral wall of the second cylinder are in sliding contact. Since the second piston is connected to the second rod by the first rod, and the second piston is connected to the opposite surface of the connecting surface of the first rod, in order to efficiently increase the drive in the contraction direction of the hydraulic cylinder. Can provide a simple structure. Furthermore, when the load exceeds a certain level during expansion, a larger cylinder output can be obtained by supplying oil to the second cylinder.

It is sectional drawing which shows the hydraulic cylinder which concerns on one Embodiment of this invention. It is explanatory drawing which shows the hydraulic drive device which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the hydraulic drive device which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the hydraulic drive device which concerns on the 3rd Embodiment of this invention.

  FIG. 1 shows a hydraulic cylinder 6 according to an embodiment of the present invention. The hydraulic cylinder 6 can be expanded and contracted in the axial direction (the vertical direction in the figure), and the press machine is driven up and down by the expansion and contraction, for example. Specifically, the hydraulic cylinder 6 includes a cylinder body 6a and a second rod 77 that can move relative to the cylinder body 6a in the axial direction, and the outer end 6b and the second rod of the cylinder body 6a. The outer end portions 77a of the 77 are respectively connected to a driving object (for example, a pair of crushing arms constituting the crusher).

  The cylinder body 6a has a shape in which two cylinders having different outer diameters are joined together with the central axis in the axial direction, and the second cylinder 71 is a cylinder having an outer end 6b. The first cylinder 61 is a cylinder having one end 68 closed and the other end 69 coupled to the second cylinder 71 by, for example, a screw or a flange, and an inner diameter smaller than that of the second cylinder 71.

One end of the second rod 77 protrudes outside the cylinder body 6a, and the other end is loaded in the second cylinder 71 and connected to the second piston 75 that is in sliding contact with the inner peripheral wall. The second piston 75 defines a second head side chamber 76 and a second rod side chamber 72 by partitioning the inside of the second cylinder 71 in the axial direction. The second rod 77 extends in the axial direction from the second piston 75 to the second rod side chamber 72 side, passes through a second through hole 82 formed in the other end 79 of the second cylinder 71, and is outside the cylinder body 6a. Protruding.
A seal member (not shown) is attached to the second through hole 82 at its inner periphery to block the gap with the second rod 77 and prevent oil leakage.

  The 1st rod 67 is loaded in the 1st cylinder 61, and is connected with the 1st piston 65 which slidably contacts the inner peripheral wall. The first piston 65 divides the inside of the first cylinder 61 in the axial direction, thereby forming a first head side chamber 66 and a first rod side chamber 62. The first rod 67 extends in the axial direction from the first piston 65 to the first rod side chamber 62 side, passes through the through hole 80 of the other end 69, protrudes into the second head side chamber 76 of the second cylinder 71, and its end Is connected to the second piston 75.

A seal member (not shown) is attached to the through hole 80 at its inner periphery to close the gap with the first rod 67 and prevent oil leakage.
In FIG. 1, the other end 69 of the first cylinder 61 is formed of the same member as the lid of the one end 78 of the second cylinder 71, but may be a separate member. Also in this case, each member is provided with a through-hole having a common central axis, and the first rod 67 passes through the through-hole in the other end 69 and the through-hole provided in the lid member at one end 78 of the second cylinder 71. Thus, it protrudes into the second head side chamber 76 of the second cylinder 71.

The second piston 75 is in sliding contact with the inner peripheral wall of the second cylinder 71, and the first piston 65 is in sliding contact with the inner peripheral wall of the first cylinder 61. The inner diameter of the second cylinder 71 and the outer diameter of the second piston 75 are larger than the inner diameter of the first cylinder 61 and the outer diameter of the first piston 65, respectively.
A third port 73 and a fourth port 74 are formed on one end 78 side and the other end 79 side of the second cylinder 71 so that oil can move from the outside of the hydraulic cylinder 6 to the outside. Similarly, a first port 63 and a second port 64 are formed on one end 68 side and the other end 69 side of the first cylinder 61, respectively.

  When one end of the second piston 75 is in contact with the other end 79 of the second cylinder 71, the first piston 65 is not in contact with the other end 69 of the first cylinder, and at this time, the first rod side chamber 62 is in a predetermined state. The length of the first rod 67 is set so as to have a volume. As a result, even when a predetermined amount of oil enters the second rod side chamber 76 of the second cylinder 71 having a large diameter and the second piston 75 moves in the direction of the other end 79 of the second cylinder 65, the first piston 65 Since the second piston 75 comes into contact with the other end 79 of the second cylinder and stops moving before it comes into contact with the other end 69 of the first cylinder, it is possible to prevent the smaller first cylinder 61 from being damaged. Can do.

The hydraulic drive device 13 according to the first embodiment of the present invention will be described with reference to FIG.
<When stretched>

When the hydraulic cylinder 6 extends, the hydraulic circuit 13 constitutes an extension drive oil passage.
The solenoid 3a of the switching valve 3 is energized during expansion. As a result, the oil discharged from the hydraulic pump passes through the A port 3A and enters the head side chamber 66 of the first cylinder 61 from the first head side oil passage 6A, and the pressure causes the first piston 65 to move to the volume of the first head side chamber 66. Is moved in the direction of increasing (downward in FIG. 2). Then, since the volume of the first rod side chamber 62 is reduced, the oil is discharged from the second port 64 (see FIG. 1) of the first cylinder 61, passes through the first rod side oil passage 6B, and the T port of the switching valve 3 The oil flows from 3T to the oil tank 31.

  On the other hand, since the second piston 75 is connected to the first piston 65 via the first rod 62, it moves at the same speed in the direction in which the first piston 65 moves, that is, the direction in which the second rod 72 extends. For this reason, the volume of the second head side chamber 76 increases and the volume of the second rod side chamber 72 decreases. That is, the direction of the oil flow is such that the second head side oil passage 7A of the second cylinder 71 is in the entering direction and the second rod side oil passage 7B is in the outgoing direction.

At this time, the switching valve 4 is in the neutral position 4C, the A port 4A, the B port 4B, and the T port 4T are connected in the same circuit, and the second head side oil passage 7A and the second rod side oil passage 7B are connected. . For this reason, the oil moves from the second rod side oil passage 6LB to the second head side oil passage 7A. At this time, if the oil is insufficient, the oil can be supplied from the T port 4T.
The extension of the second rod 72 continues until the first head-side pressure switch 7 is activated.
As described above, since the large cylinder (first cylinder 71) can be moved by the same distance as the small cylinder by the flow rate of oil applied to the small cylinder (first cylinder 61), speed increase can be achieved.

When the first piston 65 reaches near the second port 64 (not shown in FIG. 2) and a load is applied, the oil pressure in the first rod side oil passage 6B increases. When this pressure exceeds a predetermined value, the first head-side pressure switch 7 is actuated to send a signal for energizing the solenoid 4a of the switching valve 4. Then, the oil discharged from the hydraulic pump 1 enters the second head side chamber 76 from the A port 4A of the switching valve 4 through the second head side oil passage 7A, and the second rod 77 is extended and pressurized.
The oil discharged from the second rod side chamber 72 returns to the oil tank 31 from the T port 4T of the switching valve 4 through the second rod side oil passage 7B. When the pressure of the oil in the second head side oil passage 7A rises and this pressure exceeds a predetermined value, the second head side pressure switch 9 is operated, and the energization to the switching valve 3 and the switching valve 4 is stopped. The hydraulic cylinder 6 stops as it is.
As a result, when a load greater than a predetermined value is applied to the small cylinder (first cylinder 61), the larger cylinder (second cylinder 71) is pressurized, so that the hydraulic cylinder drive is efficiently increased when there is no load and when the load is low. Higher cylinder output can be obtained when the load exceeds a certain level.
<When contracted>

When the hydraulic cylinder 6 contracts, the hydraulic circuit 21 forms a contraction drive oil passage.
When contracting, the solenoid 3b of the switching valve 3 is energized. As a result, the oil discharged from the hydraulic pump enters the first rod side chamber 62 through the B port 3B and the first rod side oil passage 6B, and the first piston 65 increases the volume of the first rod side chamber 62 by the pressure. It moves in the direction (upward direction in FIG. 2). Then, since the volume of the first head side chamber 66 is reduced, oil comes out from the first port 63 (see FIG. 1) of the first cylinder 61, passes through the first head side oil passage 6A, and the T port 3T of the switching valve 3. To the oil tank 31.

On the other hand, since the second piston 75 is connected to the first piston 65 via the first rod 62, it moves at the same speed in the direction in which the first piston 65 moves, that is, the direction in which the second rod 72 contracts. For this reason, the volume of the second head side chamber 76 decreases and the volume of the second rod side chamber 72 increases. That is, the oil flow direction is such that the second rod side oil passage 7B of the second cylinder 71 is in the entry direction and the second head side oil passage 7A is in the exit direction.
At this time, the switching valve 4 is in the neutral position 4C, the A port 4A, the B port 4B, and the T port 4T are connected in the same circuit, and the second head side oil passage 7A and the second rod side oil passage 7B are connected. . For this reason, the oil moves from the second head side oil passage 7A to the second rod side oil passage 7B. At this time, excess oil returns to the oil tank 31 from the T port 4T.

The contraction of the second head 72 continues until the first rod side pressure switch 8 is activated.
When the first piston 65 reaches close to the first port 63 (see FIG. 1), the pressure of the oil in the first head side oil passage 6A increases. When this pressure exceeds a predetermined value, the first rod side pressure switch 8 is actuated to stop energization of the switching valve 3.
By the above operation, the large cylinder (second cylinder 71) can be moved the same distance as the small cylinder by the small flow rate of oil applied to the small cylinder (first cylinder 61).

  A hydraulic drive device 14 according to a second embodiment of the present invention will be described with reference to FIG. Here, the same number is used about the same member as the hydraulic drive device 13 which concerns on 1st Embodiment, and the overlapping description is abbreviate | omitted.

  In the hydraulic drive device 14 shown in FIG. 3, the pilot check valve 10 having an allowable passage flow rate larger than the allowable passage flow rate of the switching valve 4 is installed in the hydraulic circuit 22 when the hydraulic cylinder is large and the oil flow rate is large. The pilot check valve 10 is connected to the second head side oil passage 7A communicating with the second head side chamber 76 of the second cylinder 71 and the second rod side oil passage 7B communicating with the second rod side chamber 72. The oil flows in the direction from the second rod side oil passage 7B to the second head side oil passage 7A, and the flow in the reverse direction is normally prevented.

  The pilot check valve 10 can release the unidirectionality of the oil flow by, for example, applying another oil flow (pressure), and the second rod side oil from the second head side oil passage 7A. Oil flow to the path 7B can be enabled.

In FIG. 3, the pilot check valve 10 and the first rod side oil passage 6 </ b> B communicating with the first rod side chamber 67 of the first cylinder 61 are connected to the hydraulic circuit 22 by an oil circuit, and the switching valve 11 is interposed therebetween. Provided. As the switching valve 11, for example, an electromagnetic valve is used, and the A port 11A of the switching valve 11 is connected to the first rod side oil passage 6B, the P port 11P is connected to the pilot check valve 10, and the T port 11T is connected to the oil tank 32. . By applying electricity to the switching valve 11, the unidirectionality of the flow of the pilot check valve 10 can be canceled by the pressure in the first rod side oil passage 6 </ b> B.
<When stretched>

When the hydraulic cylinder 6 extends, the hydraulic circuit 22 forms a contraction drive oil passage.
At the time of extension, as described above, the switching valve 3 is energized, and the oil discharged from the hydraulic pump enters the first rod side chamber 62 and moves in the direction in which the second rod 77 extends (downward in FIG. 3) due to the pressure. . At this time, oil is discharged from the second rod side chamber 72 of the second cylinder 71 and is guided from the second rod side oil passage 6LB through the pilot check valve 10 to the second head side chamber 76 from the second head side oil passage 7A. The oil amount deficient at this time is supplied from the T port 4T of the switching valve 4 to the oil discharged from the first rod side chamber 67 of the first cylinder 61.

  As described above, a small cylinder (first cylinder 61) and a large cylinder (second rod 77 of the second cylinder 71) with a small flow rate of oil are set to the same distance as a small cylinder (first rod 67 of the first cylinder 61). Since it can be moved, the speed increase can be achieved.

  When the first piston 65 reaches the vicinity of the second port 64 (not shown in FIG. 2) and the oil pressure in the first rod side oil passage 6B exceeds a predetermined value, the first head side pressure switch 7 is activated. Then, a signal for applying electricity is sent to the solenoid 4a of the switching valve 4. Then, the oil discharged from the hydraulic pump 1 is guided from the A port 4A of the switching valve 4 to the second head side oil passage 7A. Since the oil pressure in the second head side oil passage 7A acts in the direction to close the pilot check valve 10, the oil cannot pass through the pilot check valve 10, so that all the oil enters the second head side chamber 76, and the second The rod 77 is extended and pressurized.

  As described above, the oil discharged from the second rod side chamber 72 returns from the second rod side oil passage 7B to the oil tank 31 from the T port 4T of the switching valve 4, and the pressure of the oil in the second head side oil passage 7A. Exceeds the predetermined value, the second head side pressure switch 9 is actuated, the energization to the switching valve 3 and the switching valve 4 is stopped, and the hydraulic cylinder 6 is stopped as it is.

As a result, even if the first cylinder 71 is large and the oil flow rate increases and the amount of oil discharged from the second rod side chamber 72 exceeds the flow rate that can pass through the switching valve 4, the pilot check valve The oil can be bypassed by 10 and when a load exceeding a predetermined value is applied to a small cylinder (first cylinder 61), the cylinder is pressurized by a larger cylinder (first cylinder 71), and is hydraulic when there is no load and when the load is small. Can be efficiently accelerated, and a larger cylinder output can be obtained when the load exceeds a certain level.
<When contracted>

When the hydraulic cylinder 6 contracts, the hydraulic circuit 22 forms a contraction drive oil passage.
At the time of contraction, by energizing the solenoid 3b of the switching valve 3 as described above, the discharge oil of the hydraulic pump enters the first rod side chamber 62 through the B port 3B and the first rod side oil passage 6B, and the pressure Thus, the hydraulic cylinder 6 contracts, and the oil discharged from the first cylinder 61 flows from the T port 3T of the switching valve 3 to the oil tank 31 through the first head side oil passage 6A.

In addition, the oil discharged from the second rod side chamber 72 of the second cylinder 71 as described above along with the contraction passes through the switching valve 4 to the second head side chamber 76 from the second rod side oil passage 7A. However, if the second cylinder 71 is larger, the allowable oil amount that can pass through the switching valve 4 may be exceeded.
In this case, by applying electricity to the switching valve 11, the unidirectionality of the flow of the pilot check valve 10 is released by the pressure in the first rod side oil passage 6 </ b> B, and oil is supplied from the second head side chamber 76. The discharged oil is guided from the second head side oil passage 7A through the pilot check valve 10 to the second head side chamber 72 from the second rod side oil passage 7B.

The contraction of the second head 72 continues until the first rod side pressure switch 8 is activated.
When the first piston 65 reaches close to the first port 63 (see FIG. 1) and the pressure of the oil in the first head side oil passage 6A exceeds a predetermined value, the first rod side pressure switch 8 is activated, and the switching valve 11 and the switching valve 4 are de-energized.
By the above operation, even when the second cylinder 71 is large, the large cylinder (second cylinder 71) can be moved the same distance as the small cylinder with a small amount of oil applied to the small cylinder (first cylinder 61). And increase the speed.

A hydraulic drive device 15 according to a third embodiment of the present invention will be described with reference to FIG. Here, the same number is used about the same member as the hydraulic drive device 13 which concerns on 1st Embodiment, and the overlapping description is abbreviate | omitted.
In this embodiment, in the hydraulic drive device 13 according to the first embodiment, proximity switches 7K and 8K are used instead of the first head side pressure switch 7, the first rod side pressure switch 8, and the second head side pressure switch 9, respectively. And 9K are attached to the first cylinder 61, and other configurations are the same as those of the first embodiment.

In this way, when the first piston 65 approaches the proximity switches 7K, 8K, and 9K, a signal can be issued in response. As a sensing method of the first piston 65, for example, a method of sensing the first piston 65 with a magnet containing iron may be employed. The attachment position of the proximity switch to the first cylinder 61 can be changed as appropriate.
Although FIG. 3 shows the hydraulic drive device 13 according to the first embodiment, those skilled in the art can easily conceive that the hydraulic drive device 14 according to the second embodiment can also be applied.

The hydraulic cylinder 6 and its hydraulic devices 13, 14, and 15 according to the present invention have an advantage that the cylinder can be moved at high speed. In particular, when the load during expansion is small and during contraction, the speed is about 4 to 9 times that of the conventional product (the hydraulic cylinder 6 is only the second cylinder), and the working efficiency is increased. Further, since the oil can move between the second head side chamber 72 and the second rod side chamber 76 of the second cylinder 71, energy can be recovered, energy loss is small, and power consumption can be reduced.
Furthermore, when the hydraulic cylinder 6 is not moving, the hydraulic pump 1 is unloaded, and coupled with the above, the oil temperature is unlikely to rise. Furthermore, since the speed is increased and the output is increased (6% to 18%), when the same output is exhibited, the motor output and the pump capacity can be reduced, and the size of the hydraulic cylinder can also be reduced. is there.

A numerical calculation table for the hydraulic cylinder 6 of the present invention is shown in Table 1.
As can be seen from Table 1, when the second cylinder gives the same output, the product of the present invention can greatly shorten both the expansion time and the contraction time compared to the conventional product. Further, the output of the first cylinder of the present invention is significantly smaller than the output of the second cylinder. This indicates that the pump capacity and the motor output may be small when outputting the same output.

ここで、圧力は１４MPａ、第１シリンダの出力はロッド側の出力でシリンダを動かす力でもあり、総出力は加算した。また、第１シリンダでの伸張時間は８００ｍｍを無負荷で、２００ｍｍを負荷で伸張させる場合について計算した。なお油の圧縮による減少分は一般作動油で圧力１４MPａのとき、１%未満なので計算に含まれてない。
以下、本発明の具体例を図２に基づいて説明する。

Here, the pressure is 14 MPa, the output of the first cylinder is also the force that moves the cylinder by the output on the rod side, and the total output is added. Further, the extension time in the first cylinder was calculated for a case where 800 mm was extended with no load and 200 mm was extended with a load. The decrease due to oil compression is not included in the calculation because it is less than 1% when the pressure is 14 MPa for general hydraulic oil.
A specific example of the present invention will be described below with reference to FIG.

  A hydraulic cylinder having a second cylinder thickness of 100 mm, a rod diameter of 56 mmφ, a first cylinder thickness of 50 mm, a lot diameter of 28 mmφ, and a stroke of 600 mm was used, and a solenoid valve was used as a switching valve. Between the solenoid valve 3 and the first cylinder 61 are two hydraulic hoses of 3/8 inch diameter, and between the solenoid valve 4 and the second cylinder 71 are two hydraulic hoses of 1/2 inch diameter. The suction side pipe was 1/2 inch in diameter, and the P port and T port were 3/8 inch diameter pipes and hydraulic hoses.

The discharge capacity of the hydraulic pump was 6 liters per minute, and a 1 Kw motor was directly connected. The pump was started, the solenoid valve 3 and the solenoid valve 4 were manually operated, the first and second cylinders were operated, and after sufficient air bleeding, the pump discharge pressure was set to 11 MPa. The pressure switches 7 and 9 were both set to 10.5 MPa and the pressure switch 8 was set to 4 MPa. With no load operation, it took about 12 seconds to extend the cylinder and about 9 seconds to contract. This result almost agreed with the calculated value. It is better to set the pressure switch 8 as low as possible. When the A port of the solenoid valve 3 is energized, heat is generated when the oil returns from the cylinder through the B port to the T port. This was to reduce this.

  When a load was applied with a press, the rod was able to be compressed to 110 mm, taking an average of 15 seconds to extend the rod and about 7 seconds to contract. The total cylinder output is 10.2 tons. In order to produce this output with a conventional hydraulic cylinder without using the hydraulic cylinder of the present invention, a hydraulic pump of 16 liters per minute is required, an electric motor of 3.7 kW is required, and the output of the cylinder is set at a pressure of 13 MPa. It will be 10.2 tons. The cylinder stroke was calculated at 490 mm. The cylinder extension time is 14.4 seconds and the contraction is 9.9 seconds. The above is summarized in Table 2.

ここで、従来品については計算数値である。

Here, it is a calculated numerical value for the conventional product.

  From this embodiment, it was found that when the same output is output, the hydraulic cylinder and the hydraulic drive device according to the present invention need only a small pump capacity and an electric motor output as compared with the conventional product. Further, the extension time was substantially the same, and the contraction time could be shortened.

1 Hydraulic pump 3, 4, 11 Switching valve (solenoid valve)
3a, 3b, 4a, 11a Solenoid 3A, 4A, 11A A port 3B, 4B B port 3P, 4P, 11P P port 3T, 4T, 11T T port 3C, 4C, 11C Neutral position 5 Pilot check valve 5
6 Hydraulic cylinder 6a Cylinder body 6A First head side oil passage 6B First rod side oil passage 7A Second head side oil passage 7B Second rod side oil passage 7, 8, 9 Pressure switch 7K, 8K, 9K Proximity switch 10 Pilot Check valve 10
61 1st cylinder 62 1st rod side chamber 65 1st piston 66 1st head side chamber 67 1st rod 71 2nd cylinder 72 2nd rod side chamber 75 2nd piston 76 2nd head side chamber 77 2nd rod 93 1st port 94 1st 2 port 95 3rd port 96 4th port

Claims (7)

A first port (63) is formed on the one end side of the first cylinder (61) in which one end (68) is closed and a through hole (80) is formed on the other end (69). Drilling the second port (64),
A through hole (80) is formed at one end (78), and a second through hole (82) is formed at the other end (79). The second cylinder (71) having a larger inner diameter than the first cylinder is provided at the one end side. Drill a third port (73) and drill a fourth port (74) on the other end,
A first piston (65) in which the first rod (67) penetrating the through hole (80) is in sliding contact with the inner peripheral wall of the first cylinder, and a second piston (75) in sliding contact with the inner peripheral wall of the second cylinder; Concatenate
The hydraulic cylinder (6), wherein a second rod (77) connected to a side surface of the other end (79) of the second piston (75) passes through the second through hole (80).   When the second piston (75) is in contact with the other end (79) of the second cylinder, there is a predetermined volume between the first piston (65) and the other end (69) of the first cylinder. 2. A hydraulic cylinder (6) according to claim 1, characterized in that a chamber is formed. A hydraulic cylinder comprising a hydraulic cylinder (6) according to claim 1 or 2, a hydraulic pump (1), and a hydraulic circuit (21) for extending and retracting the hydraulic cylinder by guiding discharge oil of the hydraulic pump to the hydraulic cylinder. A drive device (13), wherein the hydraulic circuit is
Oil is guided to a first head side chamber (66) formed between the first piston (65) and one end (68) of the first cylinder, and the other end (69 of the first piston and the first cylinder). ) Is discharged from the first rod side chamber (62) formed between the second piston (75) and the other end (79) of the second cylinder. Oil discharged from the formed second rod side chamber (72) to the outside of the hydraulic cylinder is supplied to a second head side chamber (76) formed between the second piston and one end (78) of the second cylinder. An extension drive oil passage that joins the supplied oil;
Oil is supplied to the first rod side chamber (62), oil is discharged from the first head side chamber (66) to the outside of the hydraulic cylinder, and oil discharged from the second head side chamber is discharged to the second rod side chamber. A hydraulic drive device comprising a contraction drive oil passage leading to   The extension drive oil passage supplies the oil discharged from the hydraulic pump to the second head side chamber (76) when the internal pressure of the first head side oil passage (6A) communicating with the first head side chamber exceeds a predetermined value. The hydraulic drive device according to claim 3, wherein   The extension drive oil passage supplies the discharge oil of the hydraulic pump to the second head side chamber when a sensor (7K) attached to a predetermined position of the first cylinder senses the first piston. The hydraulic drive device according to claim 3.   The hydraulic circuit is a pilot that enables oil to flow from the second rod side oil passage (7B) communicating with the second rod side chamber to the second head side oil passage (7A) communicating with the second head side chamber. The hydraulic drive device according to claim 3, further comprising a check valve 10.   The contraction drive oil passage cancels unidirectionality of the pilot check valve by the pressure of oil in the first rod side chamber or the first rod side oil passage (6B), and from the second head side oil passage. The hydraulic drive device according to claim 6, wherein the oil flow to the second rod side oil passage is enabled.

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