JPS6235105A - Hydraulic actuator - Google Patents

Abstract

PURPOSE:To make a hydraulic actuator unit small in size by installing a hydraulic pump along an oil pass connecting a primary hydraulic chamber and a secondary hydraulic chamber of a double acting cylinder. CONSTITUTION:A hydraulic pump 24 is installed along an oil pass connecting a primary hydraulic chamber 12 and a secondary hydraulic chamber 13 of a double acting cylinder 11, and this hydraulic pump 24 pumps oil from the primary hydraulic chamber 12 to the secondary hydraulic chamber 13 to drive a piston 14. This constitution disuses a reserve tank of large volume as conventionally used, and instead only needs an oil cup 26 of relatively small volume. Therefore, miniaturizing of a hydraulic actuator unit is possible.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a linear stroke hydraulic actuator that directly drives a shaft using hydraulic pressure, and is applicable to various actuators mounted on a vehicle, such as an auto drive actuator, etc. It is effective when used as

[Conventional technology]

Conventionally, hydraulic cylinders driven using hydraulic pressure generally include a pump part, a reservoir (oil sump), and a hydraulic cylinder.
Since each hydraulic adjustment section is arranged separately, it is large, and there are few that can be mounted on a vehicle. In particular, it has been difficult to mount it in a narrow space within the engine room of a vehicle.

Further, the negative pressure type, gear type, solenoid type, etc. actuators mounted on current vehicles have the following problems. In the case of a negative pressure type, the output stroke is adjusted by regulating the negative pressure and atmospheric pressure using a solenoid valve using the intake negative pressure generated in the engine's intake pipe via a bellow flam. When the intake negative pressure of the engine decreases, such as when the engine is under high load, the operating capacity decreases. Furthermore, when used in diesel vehicles where the engine cannot provide negative air intake pressure, a vacuum pump is required as another source of negative pressure. Furthermore, in the case of a gear type, an electromagnetic clutch or the like requires several gears, which increases the cost and makes it difficult to reduce the weight.

The solenoid method has problems such as being able to only perform simple ON/OFF operations.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above points, and provides a small-sized hydraulic actuator that obtains a linear stroke using hydraulic pressure.

However, in conventional hydraulic cylinders, both hydraulic chambers 1 of a double-acting cylinder 1, as shown in FIG.
The oil in the reserve tank 8 is supplied to the cylinders a and lb from a hydraulic pump 2 installed separately from the double-acting cylinder 1. For this reason, the double-acting cylinder 1 is
A plurality of pipes 5 and 6 leading to the pipes 5 and 6, or a four-bottom three-position switching valve 7, etc., provided in the middle of the pipes 5 and 6 were required. In addition, oil from the reserve tank 8 is supplied to the hydraulic chambers 1a and lb of the double-acting cylinder 1 by the hydraulic pump 2.
The reserve tank 8 must be filled with an amount of oil at least equal to the volume of the hydraulic chamber 1a or 1b of the hydraulic cylinder 1. In particular, when the volume of the hydraulic chamber 1a or lb is large, the reserve tank 8 must be The amount of oil will also increase. For this reason, the reserve tank 8 could not be made smaller, and it was difficult to integrate the above-mentioned components (double-acting cylinder, piping, switching valve, reserve tank, etc.), making it difficult to mount it on a vehicle.

[Means for solving problems]

Therefore, the present invention provides an oil pump in the middle of an oil passage that communicates the first hydraulic chamber and the second hydraulic chamber of a so-called double-acting cylinder, and sends oil from the first hydraulic chamber to the second hydraulic chamber. be.

[For production]

According to the above configuration, the piston and shaft are driven by sending oil from the first hydraulic chamber to the second hydraulic chamber, so there is no need for a large oil reservoir tank as in the past, and a compact and integrated hydraulic actuator is used. It can be done.

〔Example〕

Hereinafter, a first embodiment of the present invention will be described based on the drawings.

Reference numeral 10 in FIG. 1 is a cylinder housing, and a cylindrical cylinder 1) is formed inside the cylinder housing. Inside the cylinder 1), a piston 14 is provided which partitions a first hydraulic chamber 12 and a second hydraulic chamber 13 in an oil-tight manner and is slidable within the cylinder 1). The piston 14 is fixed to one end of a shaft 17 that is oil-tightly and slidably supported by a bearing 15 of the housing 10 and a sealing O-ring 16. The other end of the shaft 17 is connected to the housing 10
It protrudes further and is connected to a driven device, such as an accelerator pedal.

The cylinder 1) is connected to the housing 1 through a seal member 29.
It is sealed by a cover 18 fixed at 0,
The piston 14 is urged toward the cover 18 by a return spring 19 disposed within the first hydraulic chamber 12. As shown in FIG. 4(a), an annular stopper part 14a is integrally formed on the piston 14 on the second hydraulic chamber 13 side, and a plurality of oil passages 14 are formed in the stopper part 14a.
b are formed radially.

Above FIG. 1, a housing 20 having a bottom surface shown in FIG. 2 is fixed to the cylinder housing 10 with a bolt via a sealing O-ring 21. A groove 22 serving as an oil passage is formed on the bottom surface of the housing 20 so as to communicate the oil passage 12a that opens to the first hydraulic chamber 12 of the cylinder housing IO and the oil passage 13a that opens to the second hydraulic chamber 13.
is formed. The first hydraulic chamber 12, the second hydraulic chamber 13, the oil passages 12a, 13a, the groove 22, etc. form an oil-tight space filled with oil. A known gear type pump 24 that performs pumping action by a combination of gears 24a and 24b is provided in the middle of the groove 22.
is the rotating shaft 2 of the motor 25 fixed to the housing 20
5a, the pump 24 sends oil from the first hydraulic chamber 12 to the second hydraulic chamber 13. This gear pump 2
4.25 has a configuration similar to that of a windshield washer fluid pump motor installed in current vehicles.

However, a reinforcing plate 24c made of a wear-resistant material is installed on the outer periphery of the gears 24a and 24b. Note that the pump may be of a type other than a gear type, such as a trochoid type.

A passage 23 that communicates with an oil chamber 27 of an oil cup 26 is opened in the middle of the groove 22 . The oil cup 26 is
It is composed of a lower case 26a fixed to the housing 20, an upper case 26b, a bellows frame 26c as an isolation means, and the like.The outer periphery of the bellows frame 26c is sandwiched between the lower case 26a and the upper case 26b in an oil-tight manner, and is connected to the oil chamber 27. The atmospheric chamber 28 is communicated with the outside through a small hole 26d of the upper case 26b. The amount of oil filled in the oil chamber 27 in the state shown in FIG. 1 is relatively small, and is set as follows. That is, when the shaft 17 is located at the leftmost end (indicated by a solid line in FIG. 1), the volume occupied by the shaft 17 in the cylinder 1) is the maximum volume, and when the shaft 17 is located at the rightmost end (indicated by a two-dot chain line in FIG. If the volume occupied by the shaft 17 in the cylinder 1) is the minimum volume when the shaft 17 is located at the maximum stroke (as shown in the figure), the amount of oil in the oil chamber 27 is at least the difference between the maximum volume and the minimum volume. Therefore, the thinner the shaft 17 is, the smaller the amount of oil in the oil chamber 27 is required. In addition to the bellows phragm, the isolation means for the oil cup 26 may be a diaphragm, a piston, or the like.

Further, the housing 10.20 is provided with a small hole 10a that communicates the inside of the cylinder 11 with the atmosphere for air removal.

A groove 20a and a small hole 20b are provided. Housing 1
The small hole 10a of 0 opens into the cylinder 1) at a position where it communicates with the first hydraulic chamber 12 and the second hydraulic chamber 13 when the piston 14 is slid in the left and right direction inside the cylinder 1). There is. Further, the small hole 10a is a groove 20a on the bottom surface of the housing 10.
It communicates with the small hole 20b via. Therefore, after oil flows in from the oil cup 26 and is sealed by the bellows flam 26c, the piston 14 is slid to open the small hole 10a.

The air inside the cylinder 1) is removed from the groove 20a and the small hole 20b, and the small hole 20b is sealed with a bolt.

Next, its operation will be explained based on the above configuration.

When the motor 25 is rotationally driven and the pump 24 performs a pumping action, the oil in the first hydraulic chamber 12 is pumped through the oil passage 12a, the oil passage 22. It is sent to the second hydraulic chamber 13 via the oil passage 13a.

As a result, the hydraulic pressure in the second hydraulic chamber 13 increases, the hydraulic pressure in the first hydraulic chamber 12 decreases, and the piston 14 and shaft 17
moves to the right to the maximum stroke. At this time, the amount of oil in the cylinder 1) changes by the stroke of the shaft 17, but the amount of oil change is equal to the amount of oil change in the oil cup 26.
The oil is supplied from the oil chamber 27.

Next, motor 25. When the pump 24 is stopped, the oil in the second hydraulic chamber 13 is pumped through the oil passage 13a, the pump 24. Oil amount 22. The oil flows into the first hydraulic chamber through the oil passage 12a, and the piston 14 returns to its original position. Note that, at this time, if the motor 25 is driven in reverse rotation to forcibly send oil from the second hydraulic chamber 13 to the first hydraulic chamber 12, the return can be made even faster.

By the way, when the piston 14 moves inside the cylinder 1) to the rightmost end (maximum stroke), the piston 14 comes into contact with a part of the cylinder housing 10 and cannot move, so only the pressure inside the second hydraulic chamber 13 will rise. As,
Since overload acts on the motor 25 and adversely affects the motor 25, the piston 14 is
The structure is shown in FIG. 3 and FIG. 4. FIG. 3 is a partially enlarged view of the piston 14 when it is located at the rightmost maximum stroke in the cylinder 1), FIG. 4(a) is a front view of the piston as seen from the axial direction of the shaft 17, and FIG. (Similarly, bl is a rear view of the piston. A plurality of shaft grooves 14C are provided in the outer peripheral sliding surface of the piston 14 along the axial direction. One end of this shaft groove 14C is connected to the second hydraulic chamber. 13, and the other end communicates with an annular groove 1)a formed on the inner periphery of the right end of the cylinder 1) when the piston 14 is located at the rightmost end (maximum stroke). Furthermore, piston 14
is at a position other than the rightmost end, the axis of the piston 14 /#
14C and the annular groove 1)a of the cylinder 1) do not communicate with each other, and the first hydraulic chamber 12 and the second hydraulic chamber 13 are oil-tightly partitioned by the piston 14. Further, on the right side of the piston 14, a large number of small holes 14d are radially provided to communicate the outer peripheral sliding surface of the piston 14 with the inside. In addition, the small hole 14d is
It may also be a radial groove 1)b provided in the abutment surface of the housing 10 that abuts the piston 14.

Therefore, when the piston 14 moves to the rightmost position (maximum stroke), the second hydraulic chamber 13 is aligned with the shaft groove 14c and the annular groove 1)a, as shown in FIG.

It communicates with the first hydraulic chamber 12 via a relief path formed by the small hole 14d and the like. Therefore, even if the motor 25 and the pump 24 send oil from the first hydraulic chamber 12 to the second hydraulic chamber 13, the oil in the second hydraulic chamber 13 flows into the first hydraulic chamber 12 via the relief path. , the motor 25 is prevented from being overloaded.

Next, a second embodiment will be described based on FIG. 5, 61). The difference from the first embodiment is that a check valve 31 that is opened and closed by a solenoid 30 is provided.
The other configurations are almost the same as those in the first embodiment, so explanations will be omitted.

In addition to the groove 22, a second groove 32 serving as a return oil passage is provided on the bottom surface of the housing 20. One end 32a of the groove A32 communicates with the first hydraulic chamber 12, and the other end 32b of the groove A32 communicates with the first hydraulic chamber 12. is in communication with the second hydraulic chamber 13 via a check valve 31. The check valve 31 is set when the solenoid 30 is OFF.
When the valve is opened, the first hydraulic chamber 12 and the second hydraulic chamber 13 are communicated with each other, and when the solenoid 30 is ON, the valve is closed. In addition, concave groove 3
A small air vent hole 20c provided in the housing 20 is opened in the branch groove 32c in the middle of the housing 20.

The motor 25 and solenoid 30 can be wired as shown in FIG. If the rating of the motor 25 is aV,
The rotation speed of the motor 25 is controlled by the variable resistor 33.
It changes continuously by changing the applied voltage to Q''-a V.The solenoid 30 changes bV(
Set it to start at <aV) or higher, and then turn it on once.
), the ON state will continue to be maintained even if the voltage is lowered, so
Until cV (<bV) where the motor 25 hardly rotates,
A variable resistor 33 is set so that the applied voltage can be changed.

Here, a, b, and c have a relationship of a>b>c>O. When driving the hydraulic actuator, once a voltage higher than bv is applied to the motor 25 and the solenoid 30, the solenoid 30
After turning on the check valve 31 and closing the check valve 31, the variable resistor 3
By changing the applied voltage from cV to aV according to No. 3, the rotation speed of the motor 25 can be continuously changed and the stroke position and speed of the shaft 17 can be arbitrarily controlled. Incidentally, the flow of oil and the operation of the piston 14 and shaft at this time are the same as in the first embodiment, so a description thereof will be omitted.

In addition, when canceling the return of the shaft 17 of the hydraulic actuator to its original position, by stopping the voltage application to the motor 25 and the solenoid 30 and turning it off,
Check valve 31 opens.

Therefore, due to the action of the return spring 19, the second hydraulic chamber 13
The oil therein rapidly flows into the first hydraulic chamber 12 via the check valve 31 and the groove 32. At this time, the return movement speed of the shaft 17 is faster than in the first embodiment.

Furthermore, according to the wiring shown in FIG. 7, the same voltage is applied to the motor 25 and the solenoid 30, but as shown in FIG. voltage to its starting voltage bv
It is also possible to do the following. At this time, solenoid 3
0 can be reduced. still,
In the second embodiment, a=12V, b=7v, c=1.
It is set to 5■.

First mentioned above. In the oil cup 26 used in the second embodiment, the oil chamber 27 is sealed from the outside by the bellow frame 26c, so oil will not leak from the oil cup 26 even if the hydraulic actuator is installed upside down. . Furthermore, in the above embodiment, the oil cup 2
Although the oil chamber 27 of No. 6 communicates with the concave groove 22 that communicates the first hydraulic chamber 12 and the second hydraulic chamber 13, the oil chamber 27 is connected to the first hydraulic chamber 12.6. Needless to say, it may be directly communicated with either one of the second hydraulic chambers 13. The first thing mentioned above
．． The hydraulic actuator of the second embodiment has the following features.

1. Since the functional parts such as the hydraulic cylinder, pump, motor, and oil cup are integrated, the actuator can be made compact.

2. The shaft is linearly driven.
It is a type.

3. When the piston moves to its full stroke, the first
．． Since the second hydraulic chamber communicates through the relief path, the structure prevents overload from being applied to the motor.

4. The oil filled inside the hydraulic actuator, including the oil cup, is sealed from the outside, so no oil will leak even if the mounting direction and mounting position are changed arbitrarily.

Furthermore, in the second embodiment, 5. When the hydraulic actuator is canceled, the piston and shaft can quickly return to their original positions.

6.M It is possible to control the motor and solenoid with simple electrical wiring. If the above-mentioned features are effectively used, the actuator can be used for a wide range of purposes, regardless of whether it is mounted on a vehicle or not.

Next, a control example in which the hydraulic actuator of the second example described above is applied to an auto drive mechanism for a vehicle will be described in a ninth example.
This will be explained based on the diagram.

Reference numeral 51 indicates the hydraulic actuator shown in the second embodiment, and a shaft (17) of the hydraulic actuator 51 is connected to an engine throttle 52. Further, the hydraulic actuator 51 is connected to the IJ4 by the controller 53.

The auto drive switch 54 is turned on, and the driver sets a desired vehicle speed using the vehicle speed setting switch 55. The controller 53 compares the set vehicle speed signal with the signal from the vehicle speed sensor 56, and when vehicle speed≦set vehicle speed, a control voltage is applied to the hydraulic actuator 51;
The motor (25) and solenoid (30) are operated to drive the hydraulic actuator 51 as described above. The shaft (17) of the hydraulic actuator 51 opens the engine throttle 52 to increase the engine speed and vehicle speed,
When the vehicle speed reaches the set vehicle speed, the controller 53 controls the voltage to the hydraulic actuator 51, and the motor (25
), and the hydraulic actuator 51 is controlled so that the vehicle speed becomes equal to the set vehicle speed. Further, when the auto drive switch 54 is turned on, if the vehicle speed is greater than the set vehicle speed, after the vehicle speed has decreased to the set vehicle speed and the vehicle speed and the set vehicle speed have become equal, the controller 53 activates the hydraulic actuator 51 in the same way as described above. Control.

Also, the brake pedal 57. When either the clutch pedal 58 or the accelerator pedal 59 is operated, a cancel sensor 60 detects the operation and sends a signal to the controller 53. While this signal is being sent, the controller 53 stops applying voltage to the hydraulic actuator 51, turns off the motor (25) and the solenoid (30), and stops the operation of the hydraulic actuator 51. Further, when the signal from the cancel sensor 60 disappears, the hydraulic actuator 51 is controlled in the same manner as described above.

As described above, the actuator of the present invention can be applied to currently used auto drive systems. In addition, currently used negative pressure actuators utilize the intake negative pressure generated in the engine intake pipe, so the responsiveness of the actuator changes due to the engine negative pressure. The actuator is a motor.

Since it has a built-in oil pump, there are no problems like the ones mentioned above.

In addition, in vehicles such as diesel vehicles that cannot generate intake negative pressure due to the structure of the engine, the hydraulic actuator of the present invention can be simply installed without installing a separate negative pressure source. For example, it can be used as an actuator to drive an auto drive.

〔Effect of the invention〕

As described above, the present invention provides the first
An oil pump is provided in the middle of an oil passage communicating the hydraulic chamber and the second hydraulic chamber, and the piston and the shaft are driven by sending oil from the first hydraulic chamber to the second hydraulic chamber. Therefore, there is no need for a reservoir tank with a large oil volume as in the past, and an oil reservoir member with a relatively small capacity, that is, an oil cup, can be used, making it possible to create a compact hydraulic actuator with integrated functional parts. . Furthermore, since the oil cup is configured to seal oil from the outside, the entire hydraulic actuator can be mounted in any direction and position without worrying about oil leakage.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a hydraulic actuator according to a first embodiment of the present invention, Fig. 2 is a bottom view of the housing along line A-A in Fig. 1, and Fig. 3 shows the vicinity of the piston at its maximum stroke. 4 (al is a front view of the piston, FIG. 4 fbl is a rear view of the piston, FIG. 5 is a cross-sectional view of the hydraulic actuator of the second embodiment, and FIG. A bottom view of the housing along line B-B, Figures 7 and 8 are wiring diagrams of the second embodiment, Figure 9 is a configuration diagram in which a hydraulic actuator is applied to an auto drive system, and Figure 10. is a hydraulic circuit diagram of a conventional hydraulic cylinder. 10...Housing, 1)...Cylinder, 12...
- First hydraulic chamber, 13... second hydraulic chamber, 14... piston. 17...shaft, 19...spring, 20...
・Housing, 22... Concave groove, 24... Pump, 2
5...Motor, 26...Oil cup, 27...
Oil chamber, 28...Atmospheric chamber, 30...Solenoid, 31
...Check valve. Representative Patent Attorney Takashi Okabe Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Figure 10

Claims (4)

[Claims] (1) A shaft that is slidably provided with one end protruding from the housing, and a shaft that is fixed to the other end of the shaft and is slidable inside the cylinder of the housing, and that has a first hydraulic chamber and a second hydraulic chamber inside the cylinder. a piston provided to define a hydraulic chamber; an oil passage forming an oil space in the housing that communicates the first hydraulic chamber and the second hydraulic chamber and is sealed from the outside; and an intermediate part of the oil passage. An oil pump provided in the oil pump for sending oil from the first oil pressure chamber to the second oil pressure chamber, and an oil reservoir member that communicates with the oil space and seals the oil from the outside. Hydraulic actuator. (2) When the piston is at its maximum stroke, the first hydraulic chamber and the second hydraulic chamber communicate with each other through a groove provided on the outer periphery of the piston and a groove provided on the inner periphery of the cylinder. A hydraulic actuator according to claim 1, characterized in that: (3) The first hydraulic chamber and the second hydraulic chamber communicate with each other via a return oil passage, and the return oil passage is provided with an on-off valve. Hydraulic actuator according to item 1. (4) The hydraulic actuator according to claim 1, wherein the oil reservoir member is divided into an oil chamber and an atmospheric chamber by a bellows frame.