KR19980069762A - Tuning of hydraulic cylinder - Google Patents

Abstract

The present invention reliably realizes the tuning down of a plurality of hydraulic cylinders with a simple configuration.

The synchronizing cylinder 5 in the tuning device 4 of the present invention is constituted by a cylinder tube 7 and a flange 9 which moves back and forth axially in the cylinder tube 7 and has a piston 8, A second pressure relief chamber 11 is formed on the front surface of the piston 8 and a third pressure relief chamber 12 is formed on the rear surface of the plunger 8 in front of the plunger 9 respectively. A stationary plunger 14 is projected from the front surface of the third pressure relief chamber 12 toward the flange 9 in the third pressure relief chamber 12 and the front end of the stationary plunger 14 is fixed to the front surface of the flange 9 And protrudes into the fourth pressure chamber 13 inside. The pressure passage (19) provided in the fixed plunger (14) is connected to the hydraulic unit (30).

Description

Tuning of hydraulic cylinder

The present invention relates to a tuning device which is installed in a hydraulic circuit using a plurality of hydraulic cylinders such as an automobile fixed-rate lift and which drives each of the hydraulic cylinders by tuning.

For example, in a hydraulic circuit such as an automobile stabilization lift that elevates and lifts an automobile with a pair of lifts each having a hydraulic cylinder, a synchronous noise is generated between the both hydraulic cylinders and the hydraulic pressure source, A tuning device with a cylinder interposed therebetween is constituted. This is because at least one piston portion is provided on a plunger or a rod that moves forward by the supply of pressure oil from an oil pressure source, a pressure oil chamber having the same cross-sectional area is formed in front of the piston portion or the flange, In the case where the plunger or the like is rotated by connecting to the hydraulic cylinder, the same amount of pressure oil is sent from the respective pressure oil chambers to the corresponding hydraulic cylinders so that the tuning of the hydraulic cylinders is obtained.

On the other hand, when the lift is lowered (the hydraulic cylinders and synchronous cylinders are restored), the hydraulic cylinders are often subjected to an external force applied by a load or the like. When the external force is small or absent, A state in which the lowering operation is very slow or not at all does not occur at the lift side due to the deterioration of the lifting performance of the lifting mechanism. Therefore, Japanese Patent Application Laid- And a rod of the cylinder is connected to the rod of the other cylinder so that the rod of the synchronous cylinder is doubled by driving the outer cylinder. According to these configurations, therefore, the smooth double- , The forced lowering) is obtained, whereas the outer cylinder The size of the synchronized cylinder assembly is increased and the cost is increased and the cylinder size and the layout of the hydraulic unit are limited. In addition, since the rod is exposed to the outside, dust and air are easily mixed, .

On the other hand, in the case of a vehicle lift, in particular, even if the synchronizing cylinder is employed, the left and right hydraulic cylinders are not synchronized due to oil leakage or the like, and a slip between the lifts or a lack of lift due to unreachability to the stroke ends , But to fix this, it is very cumbersome to manually lift or automatically lift the lift to the fullest extent.

Therefore, the first embodiment of the present invention described in claim 1 is capable of reliably performing the double-action operation of the synchronous cylinder, and moreover the structure of the hydraulic cylinder can be reliably configured to suppress the rise of the cost, And to provide a tuning device.

1 is an explanatory diagram of a tuning device for a hydraulic cylinder installed in a lift for an automobile.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

1a, 1b: lifters 2a, 2b: X-type extensible mechanism

3a, 3b: Hydraulic cylinder 4: Tuning device

5: Synchronizing cylinder 7: Cylinder tube

8: Piston 9: Plunger

10: first pressure relief chamber 11: second pressure relief chamber

12: third pressure chamber 13: fourth pressure chamber

14: stationary plunger 15: first channel

16: second conduit 17: third conduit

18: fourth pipeline 20: first correction valve

21: second correction valve 22: third correction valve

23: fourth correction valve 30: hydraulic unit

31: Oil tank 33: Pump

34: Switching valve

In order to achieve the above object, the invention according to claim 1 is characterized in that a double-acting mechanism capable of applying a hydraulic pressure in the double direction to the planetary gear by supplying pressure oil from the hydraulic pressure source to the synchronizing cylinder is provided.

In order to simplify the configuration of the double-acting mechanism in addition to the object of the invention set forth in claim 1, the double-acting mechanism includes a double-acting pressure oil chamber formed in the flange and a flow passage connected to the hydraulic pressure source And a fixed flange provided on the flange at the same time in a pressure oil chamber of the flange rotor side to protrude toward the double acting side and to be inserted into the flange coaxially and to communicate with the double oil pressure chamber.

According to a third aspect of the present invention, in addition to the object of the first or second aspect of the present invention, in order to effectively cope with uneven tuning of a hydraulic cylinder due to oil leakage or the like, the synchronous cylinder is provided with a pressure- And a correction pipe is provided for correcting the flow rate of each pressure loss chamber by an appropriate amount to equalize the flow rate.

(Example)

Hereinafter, the present invention will be described based on the drawings, taking an example in which the present invention is applied to a vehicle lifting cost lift.

As shown in Fig. 1, the automobile fixed-rate lift includes two left and right lifters 1a and 1b, and the platform of each of the lifters 1a and 1b is lifted and lowered by X- And is driven by the hydraulic cylinders 3a and 3b at the same time. The two hydraulic cylinders 3a and 3b are assembled and connected in parallel to a synchronizing device 4 composed of a synchronizing cylinder 5 and an oil pressure unit 30, The cylinders 3a and 3b extend and contract in synchronization with each other through a synchronizing cylinder 5 to raise and lower the left and right lifters 1a and 1b.

The synchronizing cylinder 5 includes a cylinder tube 7 having a partition wall 6 substantially at the center and a pressure oil chamber having a small diameter on the right side and a large pressure chamber on the left side, And a plunger 9 having a piston 8 at the rear end (the left side in the drawing) capable of being retracted in the axial direction. The plunger 9 slidably contacts the small-diameter side pressure-side oil chamber of the cylinder tube 7 and the inside of the partition wall 6 while the rear piston 8 is in sliding contact with the large- And the first pressure fluid chamber 10 is formed on the rear surface of the piston 8 and the second pressure fluid chamber 11 is formed on the front surface of the piston 8 on the large diameter side of the cylinder tube 7. [ And on the small diameter side, the third pressure oil chamber 12 is formed in front of the flange 9, respectively. A fixed plunger 14 coaxial with the plunger 9 is protruded from the front surface of the third pressure chamber 12 toward the plunger 9 in the third pressure chamber 12, Is protruded into the fourth pressure oil chamber 13 formed in the flange 9 through the front surface of the flange 9.

Here, the dimensional relationship between each pressure chamber is described. Here, the sectional area of the second pressure oil chamber 11 and the sectional area of the third pressure oil chamber 12 are set to be the same. Therefore, when the diameter of the second pressure chamber 11 is d ₁ , the diameter of the flange 9 is d ₂ , and the diameter of the fixed plunger 14 is d ₃ , the sectional area of the first pressure oil chamber 10 is A ₀ , Assuming that the sectional area of the second pressure chamber 11 is A ₁ , the sectional area of the third pressure chamber 12 is A ₂ , and the sectional area of the fixed plunger 14 is A ₃ ,

. Therefore, A ₀ = 2A ₁ + A termed the _3, by setting the _{A 1 = A 2 A 0 =} A 1 + A 2 + A 3 The relationship is obtained in the. Also here

.

On the other hand, on the large-diameter side of the cylinder tube 7, the inlet 10a of the pressure oil to the first pressure oil chamber 10 is connected to the pressure oil supply pipe 32 of the hydraulic unit 30, And the inlet 11a of the pressure oil into the second pressure chamber 11 is connected to the hydraulic cylinder 3a by the second conduit 16. [ On the small diameter side, the inlet 12a of the pressure oil to the third pressure oil chamber 12 is connected to the hydraulic cylinder 3b by the third conduit 17 and is provided inside the stationary plunger 14, The pressure oil passage 19 serving as an outlet for the pressure oil to the pressure oil chamber 13 is connected to the switching valve 34 of the oil pressure unit 30 by the fourth conduit 18. A first correction valve 20 and a second correction valve 21 are provided on the large diameter side of the cylinder tube 7 for closing the valve in a normal state and opening the valve by contact with the piston 8 A third correcting valve 22 and a fourth correcting valve 23 are provided for closing the valve on the small diameter side in the normal state and opening the valve by contact with the flange 9, respectively. The first correcting valve 20 and the third correcting valve 22 are connected to each other by a correcting line 24. The correcting line 24 is in communication with the second line 16. [ The second correction valve 21 is connected to another entrance 12b provided in the third pressure chamber 12 by the correction pipe 25 and the fourth correction valve 23 is connected to the correction pipe 26 Is connected to the pressure oil supply pipe (32) of the oil pressure unit (30).

The hydraulic cylinders 3a and 3b at the connection edges of the second and third pipes 16 and 17 are provided with fuse valves 27 and 27, , 3b are prevented from being abruptly lowered.

Further, in the case of correcting the level difference of the later lifters 1a and 1b in the vicinity of the entrance 10a of the first pressure oil chamber 10 in the first conduit 15 and in the second and third conduits 16 and 17, And safety valves 28, 28 functioning in the respective positions. On the other hand, the second and third pressure oil chambers 11 and 12 are provided with air drawing valves 29 and 29, respectively.

In the oil pressure unit 30, a pump 33, a switching valve 34, and a check valve 35 are connected to the pressure oil supply pipe 32 provided between the first conduit 15 and the oil tank 31 And a relief valve 36 is provided between the pump 33 and the switching valve 34, respectively. A flow control valve 38 and a descending valve 39 interlocking with the switching valve 34 are provided to the return pipe 37 provided between the first conduit 15 and the oil tank 31 from the upstream side have. And the fourth line 18 is connected to the oil tank 31 via the switching valve 34. [

Next, the operation of the tuning device 4 configured as described above will be described. The pressure oil is supplied from the first conduit 15 to the first pressure oil chamber 10 through the check valve 35 and the check valve 35 at the position of Fig. 9) to the front. The volume of the second pressure chamber 11 and the pressure chamber of the third pressure chamber 12 becomes narrow so that the hydraulic fluid in the second pressure chamber 11 flows from the inlet port 11a to the second conduit 16 and flows into the hydraulic cylinder 3a, And the operating fluid in the third pressure chamber 12 flows from the port 12a to the third conduit 17 and is sent to the hydraulic cylinder 3b. The hydraulic cylinders 3a and 3b having the same flow rate operate in synchronism with each other because the sectional areas of the second pressure chamber 11 and the third pressure chamber 12 are the same and both lifters 1a and 1b move in the same direction Rise.

On the other hand, at the time of lowering, the switching valve 34 and the lowering valve 39 are simultaneously switched to the lowering side so that the pressurized oil flows from the fourth line 18 through the pressure passage 19 in the stationary plunger 14 to the fourth pressure- The cross sectional area of the pressure passage 19 plus the hydraulic pressure acts on the flange 9 as shown in Fig. The hydraulic pressure applied to the hydraulic cylinders 3a and 3b by the load also flows from the second conduit 16 through the second hydraulic oil chamber 11 to the third conduit 17 via the third hydraulic oil chamber 12, 8 and the flange 9, the piston 8 is retracted by the resultant force of both. The operating oil of the first pressure chamber 10 is returned from the first conduit 15 to the oil tank 31 through the return pipe 37 by the switching of the lower valve 39, The descending speed of both lifters 1a and 1b does not change even if the load applied to both lifters 1a and 1b fluctuates because the flow rate through return pipe 37 is made constant. Of course, even if the load applied to both lifters 1a and 1b is zero, the descending speed does not become slow due to the pressure transmitted from the pressure passage 19 to the fourth pressure chamber 13.

In this connection, when the lifters 1a and 1b are initially operated at the time of initial setting, since air enters the second pressure-relief chamber 11 and the third pressure-relief chamber 12, Up operation is performed without raising the back. Since the plunger 9 reaches the most advanced position and opens the third and fourth correction valves 22 and 23 respectively, the pressure oil from the pump 33 is supplied to the fourth correction valve 26 via the correction pipe 26, Is sent from the second pipe 23 to the third pressure chamber 12 and then from the third pipe 17 to the hydraulic cylinder 3b to raise the lifter 1b. Simultaneously, the pressure oil in the third pressure chamber 12 is sent to the second hydraulic chamber 11 and the hydraulic cylinder 3a via the third correction valve 22, the correction pipe 24, the second pipe 16, The lifter 1a is lifted. When the air is pulled out by the air drawing valves 29 and 29 and the rising and falling are repeated several times, the air in the second and third pressure oil chambers 11 and 12 is completely drawn out and filled with the working oil. The air in the fourth pressure chamber 13 is sent from the pressure passage 19 to the oil tank 31 through the fourth conduit 18 and the switching valve 34 at the time of rising and is discharged to the atmosphere, The air drawing is completed by repeating the descent.

Thus, in the synchronizing device 4, the plunger 9 of the synchronizing cylinder 5 adopts a double-acting mechanism such as the fourth pressure-relief chamber 13 or the stationary plunger 14 so that the downward movement of the hydraulic cylinders 3a and 3b It can be reliably performed at a constant speed irrespective of the presence or absence of the load or the magnitude of the load. Of course, even if the viscosity of the oil increases at low temperatures, there is no effect on the descending speed. In addition, without using an external cylinder or the like, by incorporating a synchronous mechanism in the synchronizing cylinder 5

(1) Since the synchronizing cylinder 5 can be reduced in size and weight, increase in cost can be suppressed, and occurrence of trouble can be reduced, and high reliability can be obtained.

(2) Since the layout of the hydraulic unit can be easily made without being restricted by the installation direction or the position setting, the entire circuit can be downsized.

(3) Since there is no part touching the outside air, there is no mixing of dust, air, etc., so that reliable operation and improvement of durability can be expected.

In particular dimensional relationship described earlier, in this embodiment, that is, the cross-sectional area of the cross-sectional area A ₀ The second pressure loss of the first pressure loss A ₁ + a third cross-sectional area of the cross-sectional area A ₂ of the pressure loss, the second pressure loss A ₁ = 3 The secondary hydraulic pressure generated in the second and third pressure chambers 11 and 12 becomes higher than the primary hydraulic pressure applied to the first pressure chamber 10 from the relationship of the sectional area A ₂ of the pressure chamber, 3a, 3b) becomes even stronger. In other words, in order to obtain the same thrust, the hydraulic cylinders 3a and 3b of this embodiment can be made thinner, and furthermore, the lifters 1a and 1b can be made to have a lowered thickness.

According to the above dimensional relationship, the area ratio between the pressure chambers is large, and the hydraulic pressures of the second and third pipes 11 and 12 and the first pressure oil chamber 10 at the time of lowering are suppressed to a low level. The compression rebound of the compression oil at the time of stopping is reduced and an effect of reducing the jump shock of the lifters 1a and 1b can be obtained. On the other hand, the X-type telescopic mechanisms 2a and 2b are usually provided with a safety device for preventing descent such as a rack and a locking pawl. However, even if the descending operation is performed in a state where the locking pawl is engaged with the rack, It is not necessary to apply extra strength to the lifter side since no force is applied. Therefore, it is possible to prevent an increase in cost, which leads to a lowering of the lifter.

In this embodiment, further characteristic correction operation will be described below by case.

Correction 1 (when both or one of the second and third pressure oil chambers 11 and 12 is decreased in hydraulic fluid and both lifters 1a and 1b have insufficient head or step difference)

First, in the case of correcting to the upper limit, when the lifter 1a and 1b are lifted up and the flange 9 is moved to the foremost position, the flange 9 contacts the third and fourth correction valves 22 and 23 , The both correction valves are opened. The fluid is not sent to the first pressure fluid chamber 10 where the pressure fluid is filled and is sent to the third pressure fluid chamber 12 through the correction pipe 26 and the fourth correction valve 23 Loses. The pressurized oil in the third pressure chamber 12 is sent from the inlet port 12a and the third conduit 17 to the hydraulic cylinder 3b and is sent from the third correction valve 22 to the correction conduit 24, And is also sent from the hydraulic cylinder 16 to the hydraulic cylinder 3a. Therefore, even if the flange 9 is stopped, both the hydraulic cylinders 3a and 3b operate up to the stroke end, so that the pressurized oil is in a full state and the steps of the lifters 1a and 1b are corrected.

Calibration 2

In the case of correction in the case of the correction 1, in the case of correction in the lower limit, the piston 8 is brought into contact with the first and second correction valves 20 and 21 by moving the plunger 9 to the most retreated position by performing the lowering operation, The both correction valves are opened. The lifters 1a and 1b and the hydraulic cylinders 3a and 3b reach the lower limit and the hydraulic oil returns from the hydraulic cylinders 3a and 3b. 3 The pressure loss chambers 11 and 12 are in a vacuum state. The operating oil of the oil tank 31 enters the first pressure oil chamber 10 from the return pipe 37 through the first conduit 15 and flows into the first correction valve 20 to the second pressure relief chamber 11 via the correction conduit 24 and the second conduit 16 by atmospheric pressure. Likewise, the operating oil that has entered the first pressure-relief chamber 10 is also sent to the third pressure-relief chamber 12 via the second correction valve 21, the correction conduit 25, and the port 12b. Therefore, all of the second and third pressure oil chambers 11 and 12 are filled with hydraulic oil, and the stepped portions of the lifters 1a and 1b are corrected.

Correction 3 [Case where the pressure loss at one or both of the second and third hydraulic chambers 11 and 12 increases and reaches a step or a lower limit to the lifters 1a and 1b]

First, in the case of correcting at the upper limit, the lifting operation is performed and the operation is performed until either one of the lifters 1a and 1b reaches the upper limit. At this time, the flange 9 does not reach the most advanced position. Here, when the lifter 1b first reaches the upper limit, the oil pressure in the third oil pressure chamber 12 is increased to about twice the maximum oil pressure generated in the pump 33. [ Then, the third correction valve 22 operates as a relief valve, opens the valve to send the pressure oil to the hydraulic cylinder 3a of the lifter 1a side from the correction conduit 24, the second conduit 16, 1a to the upper limit. At the same time, the safety valve 28 connected to the third conduit 17 also operates to reduce the hydraulic pressure in the copper pipe 17. Therefore, the pressure balance between the second and third pressure oil chambers 11 and 12 is taken to prevent the occurrence of an abnormal high pressure, and the step is also corrected. Thereafter, the pressurized oil from the pump 33 is circulated between the pressure oil supply pipe 32, the return pipe 37, and the oil tank 31.

On the other hand, when the lifter 1a first reaches the upper limit, the hydraulic pressure on the lifter 1a side becomes abnormal high pressure by the pressure increasing effect as described above. In this case, the safety valve 28 connected to the second channel 16, The abnormally high pressure is released, so that the breakage of the apparatus can be prevented and the step difference can be corrected.

Calibration 4

In the case of correction 3, in the case of correction at the lower limit, first, the lowering operation is performed to move the plunger 9 to the most retracted position. At this time, the lifters 1a and 1b do not reach the lower limit position. The piston 8 is connected to the hydraulic cylinders 3a and 3b by the hydraulic pressure generated in both the hydraulic cylinders 3a and 3b by the self weight of the lifters 1a and 1b to open the valves of the first and second correction valves 20 and 21. [ Is supplied from the return pipe 37 through the second pipe 16, the correction pipe 24, the first correction valve 20, the first pressure oil chamber 10 and the first pipe 15 to the oil tank 31). Likewise, the operating fluid of the hydraulic cylinder 3b is supplied to the third hydraulic line 17, the third hydraulic pressure chamber 12, the correction line 25, the second correction valve 21, the first hydraulic pressure chamber 10, 15 to the oil tank 31 from the return pipe 37. Therefore, both lifters 1a and 1b can be lowered to the lower limit, and the step difference is eliminated.

As described above, according to the present embodiment, the step difference correction of the lifters 1a and 1b and the up and down reach of the lifters 1a and 1b can be performed irrespective of the upper and lower positions of the lifters 1a and 1b. Particularly, when only a simple lifting or lowering operation is carried out, the user is able to obtain favorable ease of use by automatically eliminating the level difference during use of the lifter without performing any special operation for correction.

Also, the step between the lifters may occur due to the flow rate of the pressure oil chamber as in the case, and may also occur when the platform is hit by an obstacle while the lifter is descending, or only one side is prevented from descending. However, in the present embodiment, the differential pressure between the hydraulic cylinders is relatively simple as compared with the conventional method in which the hydraulic pressure is applied to the opposite side of the hydraulic cylinder to forcibly lower the hydraulic cylinder. Therefore, by inserting the sensor for detecting the differential pressure, In this case, it is possible to prevent the step from occurring.

In the above embodiment, a plunger provided with one piston is used, and a hydraulic chamber is provided in front of the piston and in front of the flange, respectively, and two hydraulic cylinders connected to each other are tuned. However, A plurality of hydraulic oil chambers are connected in parallel to each other to form a pressure oil chamber having the same cross-sectional area between the pistons, and at the same time, three or more hydraulic cylinders are tuned by connecting these pressure oil chambers to hydraulic cylinders. Is possible.

According to the first embodiment of the present invention as set forth in claim 1, since the double-acting mechanism is incorporated in the synchronizing cylinder, the lowering operation of the hydraulic cylinder can be reliably performed at a constant speed irrespective of the presence or absence of a load or the magnitude of the load. Of course, even if the viscosity of the oil increases at low temperatures, there is no effect on the descending speed. Further, the size and weight of the synchronous cylinder can be reduced, the increase in cost can be suppressed, the occurrence of trouble can be reduced, and high reliability can be obtained. In addition, the layout of the hydraulic unit can be easily performed without being restricted by the installation direction or the position setting, and the entire circuit can be downsized. In addition, since there is no part touching the outside air, it is possible to expect reliable operation and improvement of durability because there is no mixing of dust and air.

According to the second embodiment of the present invention described in claim 2, in addition to the effect of the invention of claim 1, the double-acting mechanism can be simply configured, leading to further suppression of cost increase.

According to the third embodiment of the present invention as set forth in claim 3, in addition to the effects of the first or second aspect of the present invention, the flow rate of each oil pressure chamber is different due to oil leakage or the like due to the adoption of the correction pipe, Or even if the stroke end is not reached, it is possible to effectively correct this and maintain proper reciprocating motion of the hydraulic cylinder. Particularly, since this correction is performed at a predetermined reciprocating position of the plunger, the correction is automatically made by the normal use of the hydraulic cylinder without requiring any special operation for correction, thereby making it easy to use.

Claims (3)

A plunger which swings by the supply of pressurized oil from the hydraulic pressure source is built in, and a pressure oil chamber is formed on the king side of each of the piston and the flange, respectively, and a hydraulic cylinder And a synchronous cylinder capable of supplying the same amount of pressure oil to each of the hydraulic cylinders connected to the respective hydraulic cylinders connected to the plunger by the swash plate of the plunger, And a double acting mechanism capable of applying a hydraulic pressure in the double direction to the synchronizer cylinder by supplying the hydraulic oil from the hydraulic pressure source to the synchronizer cylinder. The method according to claim 1, Wherein the double-acting mechanism includes a double-acting pressure oil chamber formed in the flange, and a flow passage connected to the hydraulic pressure source, wherein the double-acting pressure chamber is provided in the pressure oil chamber on the king side of the flange, And the fluid passage is communicated with the double-acting pressure oil chamber. 3. The method according to claim 1 or 2, Wherein the synchronizing cylinder is provided with a correcting line for correcting and equalizing the flow rate of each pressure loss chamber by communicating the pressure loss chambers with each other at a predetermined reciprocating position of the plunger.