JP2003307203A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator for delicately and accurately controlling an oil quantity and oil pressure. <P>SOLUTION: This actuator 20 is constituted by serially arranging a motor- driven ball screw mechanism 26 for rotatably driving a ball screw 23 by an electric motor 22, and advancing-retreating a push rod 25 by a ball nut 24 threadedly engaged with the ball screw 23, and a hydraulic mechanism 30 for pushing out a hydraulic fluid from a first pressure chamber 29 by advancing a piston 27 against the elastic repulsive force of a sprint 28 by coaxially abutting the mutual push rod 25 and piston 27. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator suitable for use in a system that controls the amount of oil in a hydraulic system and the hydraulic pressure.

[0002]

2. Description of the Related Art FIG. 11 shows an example of a conventional clutch control system used in a large vehicle such as a large truck. In FIG. 11, 1 is a clutch pedal installed in a driver's seat and 2 is the clutch pedal. A master cylinder 3 that operates by depressing 1 is a clutch booster that “disengages” a clutch (not shown) via a release lever 4. When the driver depresses the clutch pedal 1, hydraulic oil is supplied by the master cylinder 2 to the clutch booster 3 The relay piston portion 6 is reached via the hydraulic piston portion 5 ′ in the latter stage, where the relay piston body 7 slides to the left side in FIG. 11 and the poppet valve body 8 repels the spring (not shown). The poppet valve 9 is opened to the air circuit (see FIG. 12) by pushing it to the left against the The hydraulic oil reaches the hydraulic piston section 5 at the previous stage from the relay piston section 6 to apply hydraulic pressure.

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. The compressed air is pushed to the right of 11 and the compressed air is directly introduced into the cylinder shell 13 of the clutch booster 3 (see FIG. 12).
As a result, the piston 14 receives the assist of compressed air and is pushed to the left side in FIG. 11 against the elastic force of the spring (not shown), and the push rod 15 connected to the piston 14 pushes the release lever 4. The release lever 4 is actuated and the clutch (not shown) is "disengaged".
It is supposed to be.

When the clutch pedal 1 is returned, the hydraulic oil returns from the hydraulic piston parts 5 and 5'in front of and behind the clutch booster 3 and the relay piston part 6 to the master cylinder 2, while the relay piston of the relay piston part 6 is released. Body 7 and poppet valve body 8 of poppet valve section 9
11 is returned to the right side in FIG. 11 by the restoring force of a spring (not shown), the air circuit for the air tank 10 side is closed, and the compressed air behind the piston 14 in the cylinder shell 13 passes through the double check valve 11 and then in the relay piston body 7. It passes through the passage and enters the front of the piston 14 in the cylinder shell 13, and further passes through the cylinder exhaust port of the clutch booster 3 and the joint portion 1 of the relay valve 16.
7, the push rod 15 connected to the piston 14 is retracted to the original position and the release lever 4 is returned, so that the clutch (not shown) is brought into "engagement".

Although the manual operation by the clutch pedal 1 has been described above, in the clutch control system shown here, automatic operation can be performed by electronic control of the control device 18 which controls the automatic transmission. More specifically, when the shift is started by operating the select lever of 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 to send the clutch control solenoid valve 1
The port 9 is opened, whereby the compressed air from the air tank 10 is sent to the normally closed relay valve 16, and the port is opened by using this as an air signal, so that the compressed air passes through the relay valve 16 from another route and the double check valve 1
1, the piston 12 is pushed to the left side in FIG. 11 in the double check valve 11, and compressed air is directly introduced into the cylinder shell 13 of the clutch booster 3, whereby the piston 14 moves to a spring (not shown). The push lever 15 connected to the piston 14 pushes the release lever 4 against the resilience and pushes the release lever 4 to actuate the release lever 4 to disconnect the clutch (not shown). It is designed to be.

When the automatic shift is completed and the difference between the engine rotation and the clutch rotation falls within the specified value, the control device 18
The electronic signal from the clutch control solenoid valve 19 to the
As a result, the output port of the relay valve 16 is switched to the exhaust port, and the compressed air in the cylinder shell 13 of the clutch booster 3 is discharged from the exhaust port of the relay valve 16 to the joint portion 17 via the double check valve 11. Then, the piston 14 is returned to the right side in FIG. 11 by the returning force on the clutch side so that the clutch is in the "contact" state.

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 are combined so that they can be appropriately selected. It is used in such a way that manual operation by the clutch pedal 1 is selected when a subtle clutch operation is required at the time of stopping, etc., but such a subtle clutch operation is turned on / off by a large volume of compressed air. It is technically difficult to substitute such automatic operation as a substitute, and this is a major factor that prevents full automation of clutch operation in large vehicles.

[0008]

However, an actuator capable of coping with a delicate clutch operation in the clutch control system as described above, that is, an actuator capable of delicately and accurately controlling the oil amount and the hydraulic pressure is not yet available. The fact is that it has not been proposed, and the provision of such an actuator is desired as one that contributes to complete automation of clutch operation and the like.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an actuator capable of finely and accurately controlling the amount of oil and the hydraulic pressure.

[0010]

SUMMARY OF THE INVENTION According to the present invention, there is provided an electric ball screw mechanism for rotating a ball screw by an electric motor and for moving a push rod forward and backward through a ball nut screwed to the ball screw, and a piston for repulsive force of a spring. And a hydraulic mechanism for advancing against and pushing out hydraulic oil from the first pressure chamber, which are arranged in series by mutually arranging a push rod and a piston coaxially with each other.

Thus, according to such an actuator, the rotational drive of the ball screw by the electric motor is converted into the forward / backward movement of the ball nut in the axial direction of the ball screw, and the push rod is pushed through the ball nut. Since it is possible to control the speed and position of the forward / backward movement with high accuracy, the push rod advances the piston at an appropriate speed and length against the elastic force of the spring, and the hydraulic oil is moved from the first pressure chamber. By pushing out, it becomes possible to delicately and accurately control the oil amount and hydraulic pressure relating to the hydraulic oil.

Further, in the present invention, the second pressure chamber is provided so as to surround the abutting portion of the push rod of the electric ball screw mechanism and the piston of the hydraulic mechanism, and
A pressure receiving surface may be secured at an appropriate portion of the piston facing the second pressure chamber, and an oil supply port for guiding hydraulic oil to the second pressure chamber may be provided.

With this configuration, the hydraulic oil is supplied to the second pressure chamber from the oil supply port so that the hydraulic pressure is applied to the pressure receiving surface of the piston of the hydraulic mechanism, so that the piston is separated from the push rod of the electric ball screw mechanism. The automatic operation by electronically controlling the electric motor of the electric ball screw mechanism and the manual operation by supplying / discharging hydraulic oil to / from the second pressure chamber by pedal operation etc. are used together. It can be used selectively.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 10 show an example of an embodiment for carrying out the present invention, and the parts designated by the same reference numerals as those in FIG. 11 represent the same parts.

FIG. 1 is a sectional view showing a detailed structure of an actuator 20 of this embodiment, and FIG. 2 shows an example of a clutch control system adopting the actuator 20 of FIG.

Prior to explaining the detailed structure of the actuator 20, the clutch control system shown in FIG. 2 will be briefly described. In this clutch control system, the master cylinder 2 that operates when the clutch pedal 1 is depressed. And release lever 4
The actuator 20 is provided between the clutch booster 3 for connecting and disconnecting a clutch (not shown) via
The manual operation by the clutch pedal 1 and the automatic operation by electronic control of the control device 18 which controls the automatic transmission can be selectively used.

In the clutch booster 3 shown here, the hydraulic piston section at the subsequent stage is eliminated and only the hydraulic piston section 5 at the preceding stage is provided.
The hydraulic fluid sent from the actuator 20 is first guided to the hydraulic piston portion 5 and then reaches the relay piston portion 6, where the relay piston body 7 slides to the left side in FIG. Is pushed to the left against the elastic force of a spring (not shown), and the air circuit of the poppet valve portion 9 is opened (see FIG. 3).

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 is compressed. With the assistance of air, the release lever 4 is pushed by the push rod 15 connected to the piston 14 by being pushed to the left side in FIG.
Is pressed, the release lever 4 is actuated, and the clutch (not shown) is disengaged.

Further, 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, whereby the relay piston portion 6 is discharged. The relay piston body 7 and the poppet valve body 8 of the poppet valve portion 9 are returned to the right side in FIG.
The air circuit for the side is closed and the compressed air behind the piston 14 in the cylinder shell 13 passes through a new passage in the relay piston body 7 and is exhausted to the atmosphere from the exhaust port 21 (a part of the compressed air is the cylinder shell). 13 also enters in front of the piston 14), the push rod 15 connected to the piston 14 retreats to its original position and the release lever 4 is returned, so that the clutch (not shown) is brought into "engagement". .

The detailed structure of the actuator 20 of the present embodiment will be described below with reference to FIGS. 1 and 4 to 10.

As shown in FIG. 1, this actuator 20
Is an electric ball screw mechanism 26 for rotating a ball screw 23 by an electric motor 22 and for moving a push rod 25 forward and backward through a ball nut 24 screwed to the ball screw 23 through a ball 24b, and a piston 27 for a spring 28. A hydraulic mechanism 30 that pushes out hydraulic oil from the first pressure chamber 29 by advancing against repellency is arranged by arranging the push rod 25 and the piston 27 coaxially and arranging them in series.

Here, the push rod 25 of the electric ball screw mechanism 26 has a shape as shown in FIG. 4, and a cup-shaped collar 31 is bolted to a flange portion 25a on the base end side thereof. The ball nut 24 is integrally fitted and held in the inside 31.

When the ball nut 24 is integrally fitted and held in the collar 31, the ball nut 2
A part of the collar 31 is caulked from the outside to the caulking groove 24a of No. 4 as a caulking portion 31a to be crimped.

The unit of the ball nut 24, the collar 31, and the push rod 25 integrated as described above is held by a housing 32 as shown in FIG. Part of the spline groove 32a formed in the portion (the remaining spline groove 3
2a forms a grease reservoir), the guide protrusions 25b provided on the upper and lower ends of the flange portion 25a of the push rod 25 are slidably fitted in the axial direction to prevent rotation in the circumferential direction. It has become.

The ball screw 23 to which the ball nut 24 is screwed is rotatably held at its base end by a bearing 34 in a housing 33.
The output shaft 22a of the electric motor 22, which is bolted to the housing 33, is integrally connected.

On the other hand, the piston 27 in the hydraulic mechanism 30 has a shape as shown in FIG. 6, and has two large pistons which are in liquid-tight contact with the inner peripheral surface of the housing 35 at the front and rear positions in the axial direction. The large diameter portions 27a, 27b are provided with the diameter portions 27a, 27b, and the guide slits 27c extending in the axial direction are opened between the large diameter portions 27a, 27b.

Then, in the guide slit 27c,
A stopper bolt 36 fixed to the housing 35 penetrates so that the piston 27 and the stopper bolt 36 do not interfere with each other even if the piston 27 makes a maximum stroke.

As shown in FIGS. 7 and 8, the space between the large diameter portions 27a and 27b of the piston 27 is connected to a reservoir tank (not shown) through an oil hole 37 provided in the housing 35. This space is filled with the hydraulic oil led from the reservoir tank.

Further, the first pressure chamber 29 of the piston 27
A center valve 38 having a detailed internal structure shown in FIG. 9 is provided at the front end facing the center valve main body 39 movably accommodated in the center valve 38.
Is urged by a spring 41 interposed between the snap ring 40 and the snap ring 40 so as to be seated on the left side in FIG.

Here, the center valve 38 is integrally provided with a nozzle portion 39a penetrating the central portion of the large diameter portion 27a of the piston 27 slidably in the axial direction. Although the guide slit 27c side and the first pressure chamber 29 side are communicated with each other through a flow path formed in the axial center portion of the spring, the spring 41 normally resists the repulsive force of the spring 41. The guide slit 27c side and the first pressure chamber 29 side are isolated by the seal 42 of the center valve body 39 seated on the left side of the inside, and the nozzle portion 39a is separated only when the piston 27 is retracted to the initial position. The center valve body 39 is interfered with by the stopper bolt 36.
Is relatively pushed to the right side in FIG. 9, whereby the center valve body 39 is separated from the valve seat and the guide slit 2
The 7c side and the first pressure chamber 29 side are opened.

Further, as shown in FIG. 1, a housing 43 as shown in FIG. 10 is interposed between the housing 32 on the side of the electric ball screw mechanism 26 and the housing 35 on the side of the hydraulic mechanism 30. With the housing 43, the push rod 25 of the electric ball screw mechanism 26 and the hydraulic mechanism 3
The second pressure chamber 44 is formed so as to surround the abutting portion with the zero piston 27.

Further, the abutting surface of the piston 27 of the hydraulic mechanism 30 is provided with a raised portion 27d so that a slight gap is formed at the abutting portion between the push rod 25 and the piston 27. The second pressure chamber 4 around the raised portion 27d and the large diameter portion 27b by
The piston 27 is separated from the push rod 25 so that the piston 27 can move back and forth by using the portion facing 4 as a pressure receiving surface.

The housing 43 is provided with an oil supply port 45 for introducing hydraulic oil to the second pressure chamber 44. The master cylinder 2 operated by the oil supply port 45 and the clutch pedal 1 shown in FIG. Is connected to the second pressure chamber 44 by a flow path connected to the second pressure chamber 44.

Then, after operating the mode change-over switch of the driver's seat so that the controller 18 recognizes the manual mode, the clutch pedal 1 is stepped on and the second pressure in the hydraulic mechanism 30 of the actuator 20 from the master cylinder 2 is depressed. Chamber 44
When the hydraulic oil is sent to, the hydraulic pressure acts on the pressure receiving surface of the piston 27 in the second pressure chamber 44, and the piston 27 separates from the push rod 25 of the electric ball screw mechanism 26 and advances, whereby the center valve 38 Is closed and the side of the guide slit 27c and the side of the first pressure chamber 29 are isolated from each other, hydraulic oil is sent out from the first pressure chamber 29, and the clutch (not shown) is disconnected.

When the clutch pedal 1 is returned, the hydraulic oil returns from the second pressure chamber 44 to the master cylinder 2, which causes the piston 27 to retreat to the initial position by the restoring force of the spring 28. The hydraulic oil sent out is returned to the actuator 20, and the clutch (not shown) is brought into "contact".

At this time, when the piston 27 retracts to the initial position, the nozzle portion 39a of the center valve body 39 interferes with the stopper bolt 36 and the center valve body 39 is relatively pushed out to the right side in FIG. As a result, the center valve body 39 is separated from the valve seat, the guide slit 27c side and the first pressure chamber 29 side are opened, and the hydraulic pressure in the first pressure chamber 29 is reliably returned to zero.

The operation of the clutch booster 3 side when the clutch pedal 1 is depressed and when it is released is as already described before the detailed structure of the actuator 20 is explained. The explanation will be omitted because the specific contents will be duplicated.

On the other hand, if the control device 18 is made to recognize the automatic mode by operating the mode selector switch or the like in the driver's seat, when the gear shift is started by the operation of the select lever in the driver's seat or the like, the controller 18 drives the electric ball screw. An electronic signal is sent to the electric motor 22 of the mechanism 26 to rotate the ball screw 23 by the electric motor 22, whereby the ball nut 24 moves in the axial direction of the ball screw 23 and the push rod 25 advances. The piston 27 of the hydraulic mechanism 30, which is butted against the push rod 25, is pushed out against the repulsive force of the spring 28, whereby the hydraulic oil is sent out from the first pressure chamber 29 and the clutch (not shown) "disengages". Becomes

When the automatic shift is completed and the difference between the engine rotation and the clutch rotation falls within the specified value, the controller 18
From the electric ball screw mechanism 26 to the electric motor 22, the electric motor 22 is reversely rotated, whereby the ball nut 24 is returned in the axial direction of the ball screw 23, and the push rod 25 is retracted. Two
5, the piston 27 pushed out by the spring 2
The restoring force of 8 causes the actuator 20 to retreat to the initial position, whereby the hydraulic oil sent from the actuator 20 is returned to the actuator 20, and the clutch (not shown) is brought into "contact".

That is, if such an actuator 20 is adopted, the rotational drive of the ball screw 23 by the electric motor 22 is converted into the forward / backward movement of the ball nut 24 in the axial direction of the ball screw 23, and the ball nut 24 is moved. Since the speed and position of the forward / backward movement of the push rod 25 via the control device 18 can be accurately controlled by the control device 18, the push rod 25 resists the repulsive force of the spring 28 so that the piston 27 has an appropriate speed and position. By pushing out the hydraulic oil from the first pressure chamber 29 by advancing by the length, it becomes possible to supply the hydraulic oil to the clutch booster 3 while controlling the oil amount and hydraulic pressure delicately and accurately. A subtle clutch operation will be realized.

Therefore, according to the above embodiment, the control device 1
Since the speed and position of the forward / backward movement of the push rod 25 can be accurately controlled by the electronic control of the electric motor 22 by 8, the hydraulic oil is supplied to the clutch booster 3 while delicately and accurately controlling the oil amount and hydraulic pressure. Further, it is possible to realize a clutch control system capable of automatically performing delicate clutch operation at the time of starting or stopping.

Moreover, particularly in this embodiment, the push rod 25 of the electric ball screw mechanism 26 and the hydraulic mechanism 30 are used.
Of the master which operates by the clutch pedal 1 by providing a second pressure chamber 44 so as to surround the abutting portion of the piston 27 and securing a pressure receiving surface at an appropriate portion of the piston 27 facing the second pressure chamber 44. Since the cylinder 2 and the second pressure chamber 44 are connected to each other through the flow path, the clutch pedal 1 is depressed to move the second pressure chamber 44 in the hydraulic mechanism 30 of the actuator 20 from the master cylinder 2.
Working oil is sent to the piston 2 in the second pressure chamber 44.
The piston 27 can be separated from the push rod 25 of the electric ball screw mechanism 26 and advanced by applying hydraulic pressure to the pressure receiving surface of the electric ball screw mechanism 7. Therefore, the clutch can be obtained by electronically controlling the electric motor 22 of the electric ball screw mechanism 26. The automatic operation and the manual operation of the clutch by the clutch pedal 1 can be used in combination and selectively used.

However, in the embodiment shown in FIGS. 1 to 10 described above, automatic clutch operation by electronically controlling the electric motor 22 of the electric ball screw mechanism 26,
The clutch control system uses the clutch pedal 1 to manually operate the clutch, but the hydraulic system from the clutch pedal 1 to the second pressure chamber 44 in FIG. It is also possible to use a fully automatic clutch control system that controls the amount and hydraulic pressure of the hydraulic oil.

The actuator of the present invention is not limited to the above-mentioned embodiment, and is not limited to the clutch control system provided with the clutch booster having both hydraulic and air circuits, and only the hydraulic system. The present invention can be applied to the clutch control system of the present invention, and can also be applied to a system for controlling the oil amount and hydraulic pressure of various hydraulic systems other than the clutch. Needless to say, various changes can be made without departing from the range.

[0046]

According to the above-mentioned actuator of the present invention, various excellent effects as described below can be obtained.

(I) According to the invention described in claim 1 of the present invention, the speed and position of the forward / backward movement of the push rod can be accurately controlled by the electronic control of the electric motor by the control device. With the push rod, the piston can be pushed out by an appropriate speed and length against the elastic force of the spring to push out the hydraulic oil from the first pressure chamber, and the oil amount and hydraulic pressure related to the hydraulic oil can be delicately and accurately controlled. can do.

(II) According to the second aspect of the present invention, the working oil is supplied to the second pressure chamber from the oil supply port to apply the hydraulic pressure to the pressure receiving surface of the piston of the hydraulic mechanism. Since the piston can be separated from the push rod of the electric ball screw mechanism and advanced, the automatic operation by electronically controlling the electric motor of the electric ball screw mechanism and the operation oil supply to the second pressure chamber by pedal operation etc. It can be selectively used in combination with manual operation by discharging.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an embodiment for carrying out the present invention.

FIG. 2 is a system diagram showing an example of a clutch control system adopting the actuator of FIG.

FIG. 3 is an operation explanatory view of a main part of FIG.

FIG. 4 is an exploded view of a main part of the electric ball screw mechanism of FIG.

5 is a single-part view of the housing of the electric ball screw mechanism of FIG. 1. FIG.

FIG. 6 is a single-part view of the piston of the hydraulic mechanism shown in FIG.

FIG. 7 is a single-part view of the housing of the hydraulic mechanism shown in FIG.

8 is a sectional view taken along the line VIII-VIII in FIG.

9 is a cross-sectional view showing details of a center valve of the hydraulic mechanism of FIG.

10 is a single-part view of the housing forming the second pressure chamber of FIG. 1. FIG.

FIG. 11 is a system diagram showing a conventional example.

FIG. 12 is an operation explanatory view of a main part of FIG. 11.

[Explanation of symbols]

18 Control device 20 actuators 22 Electric motor 23 Ball screw 24 ball nuts 24b ball 25 push rod 26 Electric ball screw mechanism 27 pistons 28 springs 29 First pressure chamber 30 hydraulic mechanism 44 Second pressure chamber

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Yasutomi             3-1, Hinodai, Hino City, Tokyo 1 Hino             Inside the automobile corporation F term (reference) 3H089 AA10 CC03 DA14 DA16 GG02                       JJ13                 3J057 AA07 CB09 CB11 GA64 GD20                       GD22 GD26 HH01 JJ01                 3J062 AA03 AA17 AB22 AC07 BA14                       BA35 CD12 CD22 CD45

Claims (2)

[Claims] 1. An electric ball screw mechanism for rotating a ball screw by an electric motor and moving a push rod forward and backward through a ball nut screwed to the ball screw; and a piston for advancing against a spring repulsive force to advance the piston. An actuator characterized in that a hydraulic mechanism for pushing out hydraulic oil from a pressure chamber is arranged in series with a push rod and a piston coaxially butting each other. 2. A second pressure chamber is provided so as to surround a portion where the push rod of the electric ball screw mechanism and the piston of the hydraulic mechanism are abutted, and a pressure receiving surface is provided at an appropriate portion of the piston facing the second pressure chamber. The actuator according to claim 1, further comprising an oil supply port that is secured and that guides hydraulic oil to the second pressure chamber.