JP2004162811A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of delicately and accurately controlling oil amount and oil pressure. <P>SOLUTION: A pair of electric ball screw mechanisms 26 for letting a first piston 25 advance and retract through a ball nut 24 screw-fitted in a ball screw 23 and having different screw pitch are arranged in series on the same axis by letting the first pistons 25 oppose mutually through a first pressure chamber 27. A third piston 31 advances by a second piston 29 advancing by oil pressure in a second pressure chamber 28 communicating with the first pressure chamber 27 to push hydraulic fluid out of a third pressure chamber 32 in a hydraulic fluid pressure feeding mechanism 33. Each electric ball screw mechanism 26 is arranged in parallel to constitute this actuator 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an actuator suitable for use in a system for controlling an oil amount and a hydraulic pressure of a hydraulic system.
[0002]
[Prior art]
FIG. 10 shows an example of a conventional clutch control system employed in a large vehicle such as a large truck. In FIG. 10, reference numeral 1 denotes a clutch pedal provided in a driver's seat, and 2 denotes a clutch pedal operated by depressing the clutch pedal 1. The master cylinder 3 is a clutch booster that disconnects a clutch (not shown) via a release lever 4. When the driver depresses the clutch pedal 1, the master cylinder 2 causes the hydraulic oil in the subsequent stage of the clutch booster 3 to move. It reaches the relay piston part 6 via the piston part 5 ′, where the relay piston body 7 slides to the left in FIG. 10 and the poppet valve body 8 moves to the left against the elasticity of a spring (not shown). And the air circuit of the poppet valve section 9 is opened (see FIG. 11). The hydraulic pressure is applied from the stone portion 6 to the hydraulic piston portion 5 at the preceding stage.
[0003]
Then, when the air circuit of the poppet valve section 9 is opened, compressed air is sent from the air tank 10 to the double check valve 11 via the poppet valve section 9, and the piston 12 in the double check valve 11 in FIG. When pushed to the right, the compressed air is directly introduced into the cylinder shell 13 of the clutch booster 3 (see FIG. 11), whereby the piston 14 receives the assist of the compressed air and resists the resilience of a spring (not shown) in FIG. The release lever 4 is pushed by a push rod 15 connected to the piston 14, and the release lever 4 is actuated, so that a clutch (not shown) is "disengaged".
[0004]
When the clutch pedal 1 is returned, the hydraulic oil returns to the master cylinder 2 from the hydraulic piston portions 5, 5 'and the relay piston portion 6 before and after the clutch booster 3, while the relay piston body 7 of the relay piston portion 6 The poppet valve body 8 of the poppet valve section 9 is returned to the right side in FIG. 10 by the restoring force of a spring (not shown), the air circuit for the air tank 10 is closed, and the compressed air behind the piston 14 in the cylinder shell 13 is double-check valve. After passing through the passage in the relay piston main body 7 through the passage 11 and entering the front of the piston 14 in the cylinder shell 13, is further exhausted from the joint portion 17 of the relay valve 16 via the cylinder exhaust port of the clutch booster 3, The push rod 15 connected to the When the lease lever 4 is returned, a clutch (not shown) is brought into "contact".
[0005]
The manual operation using the clutch pedal 1 has been described above. However, in the clutch control system shown here, automatic operation can also be performed by electronic control of the control device 18 that controls the automatic transmission. More specifically, when a shift is started by operating a select lever in the driver's seat or the like, an electronic signal is sent from the control device 18 to the normally closed clutch control solenoid valve 19, and the port of the clutch control solenoid valve 19 is opened. Open, whereby compressed air from the air tank 10 is sent to the normally closed relay valve 16, and this is used as an air signal to open the port to send compressed air from another path to the double check valve 11 through the relay valve 16, In the double check valve 11, the piston 12 is pushed to the left in FIG. The compressed air is directly introduced into the cylinder shell 13 of the clutch booster 3, whereby the piston 14 is pushed to the left in FIG. 10 against the resilience of a spring (not shown) and connected to the piston 14. The release lever 4 is pushed by the push rod 15, and the release lever 4 is operated, so that the clutch (not shown) is "disengaged".
[0006]
Further, when the automatic shift is completed and the difference between the engine rotation and the clutch rotation falls within a specified value, the electronic signal from the control device 18 to the clutch control solenoid valve 19 is stopped, and the output port of the relay valve 16 is exhausted. The compressed air in the cylinder shell 13 of the clutch booster 3 is discharged to the joint portion 17 from the exhaust port of the relay valve 16 via the double check valve 11, and the piston 14 is returned by the return force of the clutch. Is returned to the right side in FIG. 10 so that the clutch is brought into "contact".
[0007]
In the conventional clutch control system as described above, the manual operation by the clutch pedal 1 and the automatic operation by the electronic control of the control device 18 can be appropriately selected in combination, and mainly when starting or stopping. In such a case, a manual operation using the clutch pedal 1 is selected when a delicate clutch operation is required. However, such a delicate clutch operation can be performed on / off automatically by a large volume of compressed air. It is technically difficult to substitute for the operation, which is a major factor preventing the fully automatic clutch operation in a large vehicle.
[0008]
Prior art documents related to this type of clutch control system include the following Patent Document 1, Patent Document 2, Patent Document 3, and the like.
[0009]
[Patent Document 1]
JP 2000-179580 A [Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-147496 [Patent Document 3]
JP, 2002-213490, A
[Problems to be solved by the invention]
However, an actuator capable of responding to a delicate clutch operation in the clutch control system of FIGS. 10 and 11 as described above, that is, an actuator capable of delicately and accurately controlling the oil amount and the oil pressure is still in practical use. The fact is that the provision of such an actuator is desired to contribute to the complete automation of clutch operation and the like.
[0011]
The present invention has been made in view of the above circumstances, and has as its object to provide an actuator capable of delicately and accurately controlling an oil amount and a hydraulic pressure.
[0012]
[Means for Solving the Problems]
The present invention provides a pair of electric ball screw mechanisms having different screw pitches for rotating a ball screw by an electric motor and for moving a first piston forward and backward through a ball nut screwed to the ball screw. A second pressure chamber communicating with the first pressure chamber and having a second pressure chamber communicated with the first pressure chamber via a first pressure chamber and facing each other via a first pressure chamber. An actuator, characterized in that an operating hydraulic pressure feed mechanism configured to push out hydraulic oil from a third pressure chamber by advancing a third piston against a force is arranged in parallel with each of the electric ball screw mechanisms. .
[0013]
Thus, according to such an actuator, the rotation drive of the ball screw by the electric motor of any of the electric ball screw mechanisms is converted into the advance / retreat operation of the ball nut directed toward the axis of the ball screw, and the movement of the ball nut through the ball nut is controlled. Since the speed and the position of the reciprocating operation of the first piston are controlled with high accuracy, when the operating oil is introduced from the first pressure chamber to the second pressure chamber by the first piston, the second piston The third piston advances by an appropriate speed and length against the resilience of the spring and the hydraulic oil is pushed out from the third pressure chamber, and the oil amount and hydraulic pressure related to the hydraulic oil are delicately and accurately controlled. become.
[0014]
In addition, by selecting an electric ball screw mechanism having a coarser thread pitch, it is possible to quickly advance and retreat the ball nut in the axial direction of the ball screw. Since the ball nut can be advanced and retracted in small increments in the axial direction, when applied to a system that controls the oil amount and oil pressure of the hydraulic system, the system can be used by appropriately using a pair of electric ball screw mechanisms with different screw pitches. Both rapid and subtle actuation of the side will be realized simultaneously.
[0015]
Further, in the present invention, a fourth pressure chamber is provided so as to surround a position where the second piston and the third piston of the working hydraulic pressure feeding mechanism abut, and the third piston facing the fourth pressure chamber may be appropriately provided. A pressure receiving surface may be provided at a location, and a master cylinder operated by a clutch pedal and the fourth pressure chamber may be connected in a flow path.
[0016]
With this configuration, the third piston is separated from the second piston by sending hydraulic oil from the oil supply port to the fourth pressure chamber and applying hydraulic pressure to the pressure receiving surface of the third piston in the fourth pressure chamber. Automatic operation by electronically controlling the electric motor of any of the electric ball screw mechanisms, and manual operation by supplying and discharging hydraulic oil to and from the fourth pressure chamber by pedal operation or the like. It can be selectively used in combination.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
1 to 9 show an example of an embodiment of the present invention, and the portions denoted by the same reference numerals as those in FIG. 10 represent the same components.
[0019]
FIG. 1 is a cross-sectional view showing a detailed structure of the actuator 20 of the embodiment, and FIG. 2 shows an example of a clutch control system employing the actuator 20 of FIG.
[0020]
Prior to describing the detailed structure of the actuator 20, an outline of the clutch control system shown in FIG. 2 will be described. In this clutch control system, the master cylinder 2 which is activated by depressing a clutch pedal 1, a release cylinder The actuator 20 is provided between the lever 4 and a clutch booster 3 (clutch disconnecting means) for connecting and disconnecting a clutch (not shown). The control device 18 controls the manual operation by the clutch pedal 1 and the control of the automatic transmission. The automatic operation by electronic control can be selectively used.
[0021]
Incidentally, in the clutch booster 3 shown here, the hydraulic piston portion of the subsequent stage is abolished and only the hydraulic piston portion 5 of the preceding stage is used, and the hydraulic oil sent from the actuator 20 is supplied to the hydraulic piston portion 5. The relay piston body 7 first slides to the left in FIG. 2, and the poppet valve body 8 is pushed to the left against the elasticity of a spring (not shown). Thus, the air circuit of the poppet valve section 9 is opened (see FIG. 3).
[0022]
When the air circuit of the poppet valve section 9 is opened, the compressed air from the air tank 10 is introduced into the cylinder shell 13 of the clutch booster 3 via the poppet valve section 9, whereby the piston 14 assists the compressed air. In response to this, the spring is pushed to the left in FIG. 2 against the resilience of a spring (not shown), and the release lever 4 is pushed by the push rod 15 connected to the piston 14, and the release lever 4 is operated and not shown. The clutch is "disengaged".
[0023]
When the hydraulic oil sent from the actuator 20 is returned to the actuator 20, the hydraulic oil is extracted from the hydraulic piston portion 5 and the relay piston portion 6 of the clutch booster 3, and the relay piston body of the relay piston portion 6 is thereby removed. 2 and the poppet valve body 8 of the poppet valve section 9 are returned to the right side in FIG. 2 by the restoring force of a spring (not shown), the air circuit for the air tank 10 is closed, and the compressed air behind the piston 14 in the cylinder shell 13 is relayed. The air passes through a new passage in the piston body 7 and is exhausted to the atmosphere from the exhaust port 21 (part of the compressed air also enters the front of the piston 14 in the cylinder shell 13), and the push rod 15 connected to the piston 14 Is retracted to the original position and the release lever 4 is returned to the original position. Clutch is made in such a way that "contact".
[0024]
Hereinafter, a detailed structure of the actuator 20 of the present embodiment will be described with reference to FIGS. 1 and 4 to 9.
[0025]
As shown in FIG. 1, in this actuator 20, a ball screw 23 is rotationally driven by an electric motor 22, and a first piston 25 is moved forward and backward through a ball nut 24 screwed to the ball screw 23 via a ball 24b. A pair of electric ball screw mechanisms 26 having different screw pitches are arranged coaxially in series with the first pistons 25 facing each other via the first pressure chamber 27, and furthermore, the second ball screw mechanism 26 communicates with the first pressure chamber 27. A second piston 29 which has a second pressure chamber 28 and which is advanced by the hydraulic pressure of the second pressure chamber 28 causes the third piston 31 to advance against the resilience of the spring 30 to move the clutch booster 3 from the third pressure chamber 32. An operating oil pressure feed mechanism 33 for pushing out the operating oil to the hydraulic piston section 5 is arranged in parallel beside each electric ball screw mechanism 26. It has become concrete.
[0026]
Here, in the electric ball screw mechanism 26 on the left side in FIG. 1, the screw pitch of the ball screw 23 is formed relatively coarse, and the first piston 25 is moved forward and backward greatly with the rotation of the ball screw 23. On the other hand, in the electric ball screw mechanism 26 on the right side, the screw pitch of the ball screw 23 is formed relatively fine, and the first piston 25 is advanced and retracted with respect to the rotation of the ball screw 23.
[0027]
The first piston 25 of each of the electric ball screw mechanisms 26 has a shape as shown in FIG. 4, and a cup-shaped collar 34 is bolted to a flange 25a on the base end thereof. The ball nut 24 is integrally fitted and held therein.
[0028]
When the ball nut 24 is integrally fitted and held in the collar 34, a part of the collar 34 is crimped from the outside as a crimping portion 34a to the crimping groove 24a of the ball nut 24 and pressed.
[0029]
The unit of the ball nut 24, the collar 34, and the first piston 25 integrated as described above is held by a housing 35 as shown in FIG. Guide projections 25b provided on the upper and lower ends of the flange portion 25a of the first piston 25 are slidable in the axial direction with respect to a part of the formed spline groove 35a (the remaining spline groove 35a forms a grease reservoir). To prevent rotation in the circumferential direction.
[0030]
The ball screw 23 to which the ball nut 24 is screwed is rotatably held at the base end thereof by a bearing 37 in a housing 36, and the electric motor 22 is bolted to the housing 36. The output shaft 22a is integrally connected.
[0031]
On the other hand, the third piston 31 in the working hydraulic pressure feeding mechanism 33 has a shape as shown in FIG. 6, and two front and rear positions in the axial direction thereof are in sliding contact with the inner peripheral surface of the housing 38 in a liquid-tight manner. A guide slit 31c having large diameter portions 31a and 31b and extending in the axial direction is provided between the large diameter portions 31a and 31b.
[0032]
A stopper bolt 39 fixed to the housing 38 penetrates the guide slit 31c so that the third piston 31 and the stopper bolt 39 do not interfere with each other even if the third piston 31 strokes to the maximum. It has become.
[0033]
As shown in FIGS. 7 and 8, the space between the large diameter portions 31a and 31b of the third piston 31 is connected to a reservoir tank (not shown) via an oil hole 40 provided in the housing 38. This space is filled with hydraulic oil guided from the reservoir tank.
[0034]
Further, a center valve 41 having a detailed internal structure shown in FIG. 9 is provided at a distal end portion of the third piston 31 facing the third pressure chamber 32, and is movably housed in the center valve 41. The center valve body 42 is urged by a spring 44 interposed between the center valve body 42 and the snap ring 43 so as to be seated on the left side in FIG.
[0035]
Here, the center valve 41 is integrally provided with a nozzle portion 45 that slidably penetrates the center portion of the large diameter portion 31a of the third piston 31 in the axial direction. Although the guide slit 31c side and the third pressure chamber 32 side communicate with each other through a flow path formed in the shaft center portion, it always resists the resilience of the spring 44 in FIG. The guide slit 31c side and the third pressure chamber 32 side are isolated by the seal 46 of the center valve body 42 seated on the left side of the nozzle valve 45, and only when the third piston 31 is retracted to the initial position, the nozzle portion 45 The center valve main body 42 is relatively pushed out to the right in FIG. 9 by interfering with the stopper bolt 39, whereby the center valve main body 42 is separated from the valve seat and the guide slit 31c side and the third pressure chamber 32 side are separated. But So that the passing.
[0036]
As shown in FIG. 1, the housing 47 connecting the housing 35 on the electric ball screw mechanism 26 side and the housing 38 on the operating hydraulic pressure feeding mechanism 33 side has a first pressure chamber 27 as described above. And a second pressure chamber 28, and a fourth pressure chamber 48 surrounding the abutting portion between the second piston 29 and the third piston 31 of the operating hydraulic pressure feed mechanism 33.
[0037]
The actuation amount A of the first piston 25 of each electric ball screw mechanism 26 is ensured at the left and right positions of the first pressure chamber 27 across the communication point with the second pressure chamber 28. A similar operation amount A is secured.
[0038]
Further, a raised portion 31d is provided on the abutting surface of the third piston 31 of the working hydraulic pressure feeding mechanism 33 so that a slight gap is formed at the abutting portion between the second piston 29 and the third piston 31. This allows the third piston 31 to separate from the second piston 29 and move forward and backward using the portion facing the fourth pressure chamber 48 around the raised portion 31d and the large diameter portion 31b as a pressure receiving surface. Also, a protruding portion 29a is protruded from a portion of the second piston 29 facing the second pressure chamber 28 with the intention of ensuring a similar gap.
[0039]
The housing 47 is provided with an oil supply port 49 for guiding hydraulic oil to the fourth pressure chamber 48, and is provided between the oil supply port 49 and the master cylinder 2 operated by the clutch pedal 1 shown in FIG. Are connected in a flow path, and the hydraulic pressure generated by depressing the clutch pedal 1 is applied to the fourth pressure chamber 48.
[0040]
In FIG. 2, reference numeral 50 denotes a vehicle speed sensor for detecting a vehicle speed, and reference numeral 51 denotes a stroke sensor linked to the release lever 4 for detecting a stroke of the clutch booster 3. The vehicle speed sensor 50 and the stroke sensor 51, respectively. Is input to a control device 18 that controls the automatic transmission.
[0041]
After operating the mode change switch or the like in the driver's seat to make the control device 18 recognize the manual mode, the clutch pedal 1 is depressed to move the master cylinder 2 to the fourth pressure chamber in the operating hydraulic feed mechanism 33 of the actuator 20. When hydraulic oil is supplied to the second piston 48, the hydraulic pressure acts on the pressure receiving surface of the third piston 31 in the fourth pressure chamber 48, and the third piston 31 separates from the second piston 29 and advances. 41 is closed, the guide slit 31c side and the third pressure chamber 32 side are separated from each other, hydraulic fluid is sent out from the third pressure chamber 32, and the clutch (not shown) is "disengaged".
[0042]
When the clutch pedal 1 is returned, the hydraulic oil returns from the fourth pressure chamber 48 to the master cylinder 2, whereby the third piston 31 retreats to the initial position by the restoring force of the spring 30, whereby the third piston 31 is discharged from the actuator 20. The actuated oil is returned to the actuator 20, and the clutch (not shown) is brought into "contact".
[0043]
At this time, when the third piston 31 retreats to the initial position, as shown in FIG. 9, the nozzle portion 45 of the center valve body 42 interferes with the stopper bolt 39, and the center valve body 42 relatively moves to the right side in FIG. As a result, the center valve body 42 is separated from the valve seat, the guide slit 31c side and the third pressure chamber 32 side are opened, and the oil pressure in the third pressure chamber 32 is reliably returned to zero.
[0044]
The operation of the clutch booster 3 when the clutch pedal 1 is depressed and when the clutch pedal 1 is released is the same as that already described before describing the detailed structure of the actuator 20. Are duplicated, so the description is omitted.
[0045]
On the other hand, if the control device 18 recognizes the automatic mode by operating the mode change switch or the like in the driver's seat, when the shift is started by the operation of the select lever or the like in the driver's seat, the vehicle speed sensor 50 outputs 5 km / h, for example. Under the condition that it is confirmed that the normal running is exceeded, the controller 18 selects the electric ball screw mechanism 26 with the coarser thread pitch on the left side in FIG. 1 and controls the electric ball screw mechanism 26 toward the electric motor 22. An electronic signal is sent from the device 18 to rotate the ball screw 23 by the electric motor 22, whereby the ball nut 24 moves quickly in the axial direction of the ball screw 23, and the first piston 25 advances greatly. Hydraulic oil is sent by the first piston 25 from the first pressure chamber 27 to the second pressure chamber 28 of the working oil pressure sending mechanism 33, whereby the second piston 25 Third piston 31 through 9 are pushed against the resilience of the spring 30, thereby the clutch (not shown) hydraulic fluid is fed from the third pressure chamber 32 becomes "OFF".
[0046]
When the difference between the engine rotation and the clutch rotation falls within the specified value after the automatic shift is completed, the electric motor 22 is reversed by the electronic signal from the control device 18 to the electric motor 22 of the left electric ball screw mechanism 26. As a result, the ball nut 24 is returned in the axial direction of the ball screw 23, the first piston 25 retreats, and the second piston 29 and the third piston 31, which have been pushed out by the hydraulic pressure of the first piston 25, The hydraulic fluid sent out from the actuator 20 is returned to the actuator 20 and the clutch (not shown) is brought into "engagement" with the restoring force.
[0047]
Further, when the control device 18 recognizes the automatic mode by operating the mode change switch or the like in the driver's seat and then performs the fine movement operation of the clutch including the starting operation, the vehicle speed sensor 50 slows down, for example, 5 km / h or less. Under the condition that the operation is confirmed and the stroke sensor 51 confirms that the stroke by the clutch booster 3 is in the half-clutch range, the electric ball screw mechanism with the smaller thread pitch on the right side in FIG. 26 is selected, an electronic signal is sent from the control device 18 to the electric motor 22 of the electric ball screw mechanism 26, and the forward / reverse rotation of the ball screw 23 by the electric motor 22 is repeated. The first piston 25 similarly advances and retreats in small directions in the direction, and the first piston 25 advances and retreats. The generation and release of the hydraulic pressure from the first pressure chamber 27 to the second pressure chamber 28 of the operating hydraulic pressure feed mechanism 33 are finely repeated by the movement, and as a result, the second piston 29 and the third piston 31 move forward and backward in small steps. The connection / disconnection operation of the clutch (not shown) is realized in small increments, and a delicate clutch operation such as a half-clutch operation at the time of manual operation becomes possible.
[0048]
That is, when such an actuator 20 is employed, the rotation drive of the ball screw 23 by the electric motor 22 of each electric ball screw mechanism 26 is converted into the advancing and retreating operation of the ball nut 24 toward the axis of the ball screw 23. The speed and position of the forward / backward movement of the first piston 25 via the nut 24 can be accurately controlled by the control device 18, and the electric ball screw having a coarser thread pitch for the general operation of the clutch during normal running. By selecting the mechanism 26, a quick clutch operation speed can be obtained. On the other hand, with respect to the fine movement operation of the clutch including the starting operation, by selecting the electric ball screw mechanism 26 having a smaller screw pitch, the connection and disconnection of the clutch can be performed in small steps. Delicate clutch operation without lowering the clutch operating speed during normal driving It is possible to achieve the realization.
[0049]
In other words, in the case where the electric ball screw mechanism 26 in which the screw pitch is made finer by giving priority only to the fine movement operation of the clutch alone is employed, the clutch operation speed becomes slow in performing the general operation of the clutch during normal running, so that the automatic operation becomes smooth. There is an inconvenience that shifting may be hindered, but such inconvenience is avoided by using a pair of electric ball screw mechanisms 26 having different screw pitches.
[0050]
Therefore, according to the above embodiment, the speed and position of the forward / backward movement of the first piston 25 can be accurately controlled by electronically controlling the electric motor 22 of each electric ball screw mechanism 26, and the screw pitches differ. By appropriately using the pair of electric ball screw mechanisms 26, both the quick operation and the delicate operation of the first piston 25 can be realized at the same time. Hydraulic oil is introduced from the third pressure chamber 32 by introducing hydraulic oil into the chamber 28 and causing the third piston 31 to advance by an appropriate speed and length against the elasticity of the spring 30 by the second piston 29, Hydraulic oil can be supplied to the clutch booster 3 while delicately and accurately controlling the oil amount and the oil pressure. The clutch control system adapted to be carried out latch operation in automatic operation can be achieved without lowering the clutch operating speed.
[0051]
Further, in the present embodiment, in particular, a fourth pressure chamber 48 is provided so as to surround the abutting portion between the second piston 29 and the third piston 31 of the operating hydraulic pressure feed mechanism 33, and the fourth pressure chamber 48 is A pressure receiving surface is secured at an appropriate position of the third piston 31 and the master cylinder 2 operated by the clutch pedal 1 is connected to the fourth pressure chamber 48 by a flow path. Hydraulic oil is sent from the master cylinder 2 to the fourth pressure chamber 48 of the operating oil pressure feed mechanism 33 of the actuator 20, and the hydraulic pressure is applied to the pressure receiving surface of the third piston 31 in the fourth pressure chamber 48, whereby the third oil pressure is applied. Since the piston 31 can be advanced separately from the second piston 29 of the operating hydraulic pressure feed mechanism 33, the electric motor 22 of any of the electric ball screw mechanisms 26 can be moved. And automatic operation of the clutch due to the electronic control, a combination of a manual operation of the clutch by the clutch pedal 1 can be used selectively.
[0052]
However, in the embodiment of FIGS. 1 to 9 described above, the clutch using both the automatic operation of the clutch by electronically controlling the electric motor 22 of the electric ball screw mechanism 26 and the manual operation of the clutch by the clutch pedal 1 is used. Although the control system is adopted, the hydraulic system from the clutch pedal 1 to the fourth pressure chamber 48 shown in FIG. 2 is all abolished, and the amount and oil pressure of the operating oil from the operating oil pressure feed mechanism 33 is always controlled by each electric ball screw mechanism 26. It is also possible to provide a fully automatic clutch control system.
[0053]
The actuator of the present invention is not limited to the above-described embodiment, but is not limited to a clutch control system including a clutch booster (clutch disengaging means) having both hydraulic and air circuits. , It is also possible to apply to a clutch control system of only the hydraulic system, furthermore, it is also possible to apply to a system that controls the oil amount and hydraulic pressure of various hydraulic systems other than the clutch, It goes without saying that various changes can be made without departing from the spirit of the present invention.
[0054]
【The invention's effect】
According to the actuator of the present invention described above, various excellent effects as described below can be obtained.
[0055]
(I) According to the first aspect of the present invention, the speed and the position of the forward / backward movement of the first piston can be accurately controlled by electronically controlling the electric motor of each electric ball screw mechanism, In addition, by appropriately using a pair of electric ball screw mechanisms having different screw pitches, both the quick operation and the delicate operation of the first piston can be realized at the same time. Hydraulic oil can be pushed out of the third pressure chamber by introducing hydraulic oil into the pressure chamber and causing the third piston to advance by an appropriate speed and length against the elasticity of the spring by the second piston. It is possible to delicately and accurately control the oil amount and hydraulic pressure of the working oil.
[0056]
(II) According to the invention described in claim 2 of the present invention, hydraulic fluid is sent from the oil supply port to the fourth pressure chamber, and hydraulic pressure is applied to the pressure receiving surface of the third piston in the fourth pressure chamber. Since the third piston can be separated and advanced from the second piston, the hydraulic oil can be automatically operated by electronically controlling the electric motor of any of the electric ball screw mechanisms, and the hydraulic oil can be operated by pedaling the fourth pressure chamber. Can be selectively used in combination with the manual operation of supplying and discharging the gas.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of an embodiment of the present invention.
FIG. 2 is a system diagram showing an example of a clutch control system employing the actuator of FIG.
FIG. 3 is an operation explanatory view of a main part of FIG. 2;
FIG. 4 is an exploded view of a main part of each electric ball screw mechanism of FIG.
FIG. 5 is a single item view of a housing of each electric ball screw mechanism of FIG. 1;
FIG. 6 is a single-part view of a third piston of the working hydraulic pressure feeding mechanism of FIG. 1;
FIG. 7 is a single-piece view of a housing of the hydraulic operating mechanism of FIG. 1;
8 is a sectional view taken along the line VIII-VIII in FIG.
FIG. 9 is a cross-sectional view showing details of a center valve of the working hydraulic pressure feeding mechanism of FIG. 3;
FIG. 10 is a system diagram showing a conventional example.
11 is an operation explanatory view of a main part of FIG. 10;
[Explanation of symbols]
18 Controller 20 Actuator 22 Electric motor 23 Ball screw 24 Ball nut 24b Ball 25 First piston 26 Electric ball screw mechanism 27 First pressure chamber 28 Second pressure chamber 29 Second piston 30 Spring 31 Third piston 32 Third pressure chamber 33 Hydraulic feed mechanism 48 Fourth pressure chamber

Claims (2)

A pair of electric ball screw mechanisms having different screw pitches for rotating a ball screw by an electric motor and moving a first piston forward and backward through a ball nut screwed to the ball screw are connected to each other by a first pressure chamber. A second pressure chamber communicating with the first pressure chamber and being opposed by the second pressure chamber with a hydraulic pressure of the second pressure chamber. An actuator, characterized in that an operating oil pressure feeding mechanism configured to push out operating oil from a third pressure chamber by advancing a third piston is arranged in parallel with each of the electric ball screw mechanisms. A fourth pressure chamber is provided so as to surround the abutting portion between the second piston and the third piston of the working hydraulic pressure feeding mechanism, and a pressure receiving surface is secured at an appropriate position of the third piston facing the fourth pressure chamber. The actuator according to claim 1, wherein an oil supply port for introducing hydraulic oil to the fourth pressure chamber is provided.

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