JPH018723Y2 - - Google Patents

Description

[Detailed Description of the Invention] a. Industrial Application Field The present invention relates to a digital input type fluid pressure piston position control device.

B. Prior Art A digital input type fluid pressure piston position control device is a device that fluid-dynamically amplifies the weak output of a stepper motor or the like driven by a digital signal to control the piston position.

This type of device according to the prior art was developed, for example, by
It is disclosed in JP-A No. 56-108007, Japanese Utility Model Application Publication No. 56-113201, etc.

FIG. 7 is a sectional view of an example of this type of device according to the prior art.

A piston 3 is fitted into a cylinder hole 2 provided in the main body 1 so as to be slidable in the axial direction. The piston 3 has a thick rod 4 and a thin rod 5 at both ends.
The thick rod 4 protrudes to the outside through a hole penetrating the outer wall of the main body 1 (hereinafter the thick rod is referred to as an external rod), and the thin rod 5 connects with the drain chamber 10 provided inside the main body 1. It projects into the drain chamber 10 through a hole penetrating the partition wall (hereinafter the thin rod will be referred to as an internal rod). In addition, the external rod 4 is
A mounting screw 4a for mounting other devices is provided at its tip. On the other hand, the internal rod 5 is connected to the internal passage 5.
a, a hole 5b which is the entrance of the internal passage 5a, and a nozzle 5c provided at the tip. Cylinder hole 2
The cylinder chamber 6 which is on the external rod 4 side of the cylinder hole 2 and the cylinder chamber 7 which is on the rod 5 side of the cylinder hole 2 are connected to the passage 8.
The main body 1 is connected to a pressure fluid supply source (not shown) via a passage 9 which is a branch of the passage 8 and the passage 8 . Note that the passage 9 is provided with an aperture 9a in the middle thereof.

The tip 5 of the internal rod 5 is placed in the drain chamber 10.
A flapper member 11 having an end face 11b facing c is supported by bearings 12a and 12b so as to be movable in parallel to the sliding direction of the piston 3.

The rod 11 has a rack 11a provided on the rod 11 and a pinion 13a that meshes with the rack 11a.
The rod 11 is moved in the axial direction by rotation of a rotary drive unit (for example, a stepper motor) via a shaft 13 provided with a shaft 13 .

Pressure fluid is connected to the cylinder chamber 6 via the passage 8;
It is guided to the cylinder chamber 7 via a passage including a throttle 9a. The pressure fluid led to the cylinder chamber 7 passes through the hole 5b, the internal passage 5a, and the nozzle 5c, and then passes through the rod body 1.
1, reaches the inside of the drain chamber 10, and is discharged from the drain hole 10a provided in the drain chamber 10.

Since the passage 9 is provided with a throttle 9a, the pressure is higher on the upstream side than on the downstream side. Furthermore, since the external rod 4 is thicker than the internal rod 5, the effective area for pushing the cylinder 3 from the cylinder chamber 6 side is smaller than the effective area for pushing the cylinder 3 from the cylinder chamber 7 side.
Therefore, when the external pressure pushing on the external rod 4 and the reaction force on the rod 5 of the pressure fluid ejected from the nozzle 5c are determined, the piston 3 comes to rest at a certain equilibrium position.

To explain in more detail, the end surface 11 of the rod 11
When b approaches the nozzle 5c, since pressure fluid is supplied to the nozzle 5c via the throttle 9a as described above, the pressure in the cylinder chamber 7 gradually increases, and the force pushing the piston 3 to the left increases. do. On the other hand, pressure fluid is also introduced into the cylinder chamber 6 to constantly push the piston 3 to the right. However, since the piston area on the cylinder chamber 7 side is larger than the piston area on the cylinder chamber 6 side, if the gap between the tip of the nozzle 5c and the end surface 11b reaches a certain value, that is, the gap X in FIG. The forces pushing in the left and right directions are balanced.

When the gap becomes less than At the point where the force is balanced, the forces in the left and right directions are balanced and stop. Furthermore, when the rod 11 moves to the right and the value of the gap X increases, the fluid pressure acting on the cylinder chamber 6 causes the piston 3 and the external rod 4 to move to the right with an amplified large force, and the gap becomes X. At that point, the forces in the left and right directions are balanced and stop.

In this way, while maintaining the gap X between the left part of the nozzle 5c and the end surface 11b of the flapper member 11, the force is amplified by the fluid pressure, and the rod body 1
Follow 1.

Therefore, if the rod 11 is accurately moved by a stepper motor or the like, the position of the external rod 4 can be powerfully and accurately digitally determined while maintaining the gap X with a small torque.

c. Problems to be Solved by the Invention The digital rotational motion of a rotary drive unit such as a stepper motor in a digital input type hydraulic piston position control device has high-speed response and moves in a pulsed manner. On the other hand, since the piston moves using fluid pressure, it is difficult to follow the high-speed response of the stepper motor or the like. When the stepper motor moves the flapper member 11 at a speed higher than the response speed of the piston part, the end surface 11b of the rod 11 hits the nozzle 5c, suppressing the movement of the stepping motor and preventing normal operation. . That is, the electrical command to the stepping motor and the motor output position no longer correspond, and naturally, the piston position also no longer corresponds. For this reason, conventionally, the motor rotation speed has been limited.

d Means for Solving the Problem The above problem is solved by using a digital input type fluid pressure system in which the rotational movement of the stepper motor is once absorbed by the spring, and the movement of the end surface 11b of the flapper member 11 is matched to the response speed of the piston part. The problem was solved by a piston position control device.

More specifically, a pressure fluid supply source;
A drain chamber provided inside the main body, an internal rod having an internal passage in the axial direction and protruding into the drain chamber, an external rod protruding to the outside of the main body and having a cross-sectional area larger than the cross-sectional area of the internal rod, and the above-mentioned internal rod. A piston with the external rod fixed to both ends and having a cross-sectional area larger than that of the external rod, a cylinder hole in which the piston slides, and a piston that penetrates the wall between the cylinder hole and the drain chamber and passes through the inside of the piston. An internal rod through hole in which the rod slides, an external rod through hole in which the external rod penetrates the wall between the cylinder hole and the outside of the main body, and an external rod side of the cylinder hole. a first passage connecting the first cylinder chamber and the pressure fluid supply source; a second passage connecting the pressure fluid supply source and the second cylinder chamber on the internal rod side of the cylinder hole; A throttle provided in the middle of the second passage, an internal passage inlet hole that connects the internal passage of the internal rod and the second cylinder chamber, and an internal passage inlet hole that connects the internal passage of the internal rod and the drain chamber and that connects the internal passage of the internal rod to the second cylinder chamber and A digital input comprising a nozzle provided, a flapper member whose one end face faces the nozzle and is movable in a direction parallel to the axial direction of the piston, and flapper member moving means for moving the flapper member in response to a digital signal. In the hydraulic piston position control device, the flapper member moving means includes an intermediate shaft mechanically coupled to the flapper member to move the flapper member in the axial direction, and a pin protruding from the intermediate shaft in the radial direction. , a digital rotary drive section, a rotary plate fixed to the rotation shaft of the digital rotary drive section, one end fixed to one point of the rotary plate and the other end fixed to the above-mentioned pin, and the above-mentioned flapper member biased in the direction of the nozzle. a buffer spring consisting of a tension spring that urges the pin in the direction in which the buffer spring is fixed to the rotating plate; and a buffer spring that protrudes from the rotating plate and intersects with the pin at a position that prevents the pin from approaching within a certain limit the point where the buffer spring is fixed to the rotating plate. The problem has been solved by a digital input type hydraulic piston position control device characterized by comprising a stopper pin which is provided as a stopper pin and functions as a stopper for the rotational movement of the pin.

e. Effect The intermediate shaft connected to the flapper member, for example, by a rack and pinion, is not directly connected to the rotation drive unit, but is connected via a buffer spring.

Since the buffer spring is a tension spring, the pin stops at the position in contact with the stopper pin in a static state. That is, the highly accurate rotational position of the digital rotary drive unit 14 is converted into the position of the piston via a pin, a stopper pin, an intermediate shaft, a rack and pinion, a flapper member, and a nozzle that follows the flapper member.

When the digital rotary drive unit rotates in a pulsed manner in a direction in which the stopper pin separates from the pin, the buffer spring expands and the stopper pin separates from the pin.
Thereafter, the intermediate shaft is rotated by the elastic force of the buffer spring until the pin contacts the stopper pin. In this manner, the high-speed pulse rotational motion of the digital rotational drive unit is once absorbed by the buffer spring and gradually transmitted to the intermediate shaft using the elastic force of the spring.

The rotation of the intermediate shaft is transmitted to the flapper member via, for example, a rack and a pinion, and the piston follows the movement of the flapper member.

When the digital rotation drive unit rotates in the opposite direction, the flapper member is only subjected to a weak force in the direction away from the nozzle due to the pressure fluid from the nozzle, so the intermediate shaft is rotated by the tension of the buffer spring and the stopper pin. It is integrally coupled with the rotary drive unit, rotates without restriction in the opposite direction to the previous case, and remains stationary at an equilibrium position. The piston follows the movement of the flapper member at this time.

f Embodiment FIG. 1 is a plan sectional view of a preferred embodiment of the digital input type hydraulic piston position control device according to the present invention, and FIG. 2 is an elevational view of the buffer spring portion of FIG. 1.

Components that are the same as those of the conventional digital input type hydraulic piston position control device shown in FIG. 7 are given the same reference numerals, and explanations thereof will be omitted.

The digital rotation drive unit 14 and the intermediate shaft 13 are not directly coupled, but are coupled via a buffer spring 15. That is, a disc 16 is provided at the end of the digital rotary drive unit 14, a pin 17 and a stopper pin 18 are installed on the surface of the disc 16, and a pin 19 is installed near the end of the intermediate shaft 13. A buffer spring 15 is attached between the pins 19. Stopper pin 18 is a stopper for pin 19.

Since the buffer spring is a tension spring, the pin 19 remains in contact with the stopper pin 18 in a static state. In other words, the highly accurate rotational position of the digital rotation drive unit 14 is determined by the stopper pin 18 and the pin 1.
9, the intermediate shaft 13, and the rod 11, the position of the piston is converted while maintaining its high accuracy.

When the digital rotary drive unit 14 rotates counterclockwise at high speed in FIG. 3, the end face 11b of the rod 11 hits the nozzle 5c and is restricted by the movement of the piston 3, and the stopper pin 18 separates from the pin 19 and the buffer spring 15 expands. Since pin 19 is pulled by the buffer spring, pin 19 eventually
9 moves until it comes into contact with the stopper pin 18, and the piston 3 moves to a position corresponding to that position.

In this manner, the high-speed pulsed rotational motion of the digital rotation drive section is once absorbed by the buffer spring, and then the rod 11 is moved by the force of the buffer spring 15. When the stopper pins 18 and 19 come into contact, the digital rotary drive unit 14 and the rod 11 are integrated, and the piston 3 is accurately positioned at the above-mentioned position with respect to the rod 11.

The spring strength of the buffer spring is selected to be weak enough not to impede the rotation of the stepper motor and to be able to move the rod 11, which is the flapper member.

In the embodiment shown in FIG. 1, zero point return springs 20a and 20b are provided for returning the stepper motor to a predetermined position when the power supply to the stepper motor is stopped. The zero point return springs 20a and 20b are arranged inside the drain chamber 10 at a position where the rod 11 is inserted from both sides. When the power supply stops, rod 1 is placed at the stable point of the zero point return spring.
1 returns, and if there is fluid pressure, the piston 3 returns to the predetermined position.

Figures 3 and 4 show an embodiment in which a rotary flapper 21 is used at the end of a rod serving as a flapper member.
In this case, a rotary flapper 21 is attached to the end of the rod 11.
is installed. Since the center of rotation of the rotary flapper 21 is slightly shifted from the center of the jet stream of the nozzle 5c, the flapper 21 is constantly rotating and the accumulation of dust particles is actively prevented. Other operations are the same as those in FIGS. 1 and 2.

5 and 6 show an embodiment in which a rotary bearing 22 is used as the flapper member. The rotary bearing 22 is directly attached to the intermediate shaft 13 shown in FIGS. 1 to 4 instead of the rod 11, and uses its outer surface as a surface facing the nozzle 5c. In this case as well, since the center of rotation of the rotary bearing and the center of the jet from the nozzle 5c are slightly shifted, the bearing is constantly rotating and the accumulation of dust particles is prevented.

g Effect The present invention connects the digital rotary drive section 14 and the shaft 13 via the buffer spring 15, and further uses a stopper pin to match the high-speed response of the digital drive section and the response of the piston section. This prevents mismatch between the motor position and the electrical command, and makes it possible to set the input speed up to the response limit of the stepper motor. Although the movement of the fluid piston lags behind the movement of the stepper motor, the piston position is ultimately set with high precision in accordance with the movement of the digital drive.

Although the present invention has been described with respect to a digital input type fluid pressure piston position control device, it goes without saying that it can also be used in a digital input type fluid pressure control valve.

[Brief explanation of the drawing]

FIG. 1 is an elevational sectional view of a preferred embodiment of a digital input type hydraulic piston position control device according to the present invention, FIG. 2 is a plan sectional view of the device shown in FIG. 3, and FIG. FIG. 4 is a cross-sectional top view of the device of FIG. 3; FIG. 5 is a cross-sectional elevation view of yet another preferred embodiment; FIG.
This figure is a plan sectional view of the device shown in FIG. 5, and FIG. 7 is a sectional view of an example of a digital input type hydraulic piston position control device according to the prior art. 3... Piston, 4... External rod, 5... Internal rod, 5c... Nozzle, 10... Drain chamber, 11... Flapper member, 13... Intermediate shaft, 14... Digital rotation drive device, 15... Buffer spring, 16... Disc, 1
7, 19...pin, 18...stopper pin, 20
a, 20b...Zero point return spring, 21...Rotating flapper, 22...Bearing.

Claims (1)

[Claims for Utility Model Registration] (1) A pressure fluid supply source, a drain chamber provided within the main body, an internal rod having an internal passage in the axial direction and protruding into the drain chamber, and a disconnection protruding from the outside of the main body. an outer rod having an area larger than the cross-sectional area of the inner rod; a piston having the inner rod and the outer rod fixed to both ends and having a cross-sectional area larger than the cross-sectional area of the outer rod; a cylinder hole in which the piston slides; an internal rod through hole that penetrates the wall between the hole and the drain chamber and in which the internal rod slides; and an internal rod through hole that penetrates the wall between the cylinder hole and the exterior of the main body and in which the external rod slides. A sliding through hole for the external rod, a first passage connecting the pressure fluid supply source to a first cylinder chamber on the external rod side of the cylinder hole, and a second passageway on the internal rod side of the cylinder hole. a second passage connecting the cylinder chamber and the pressure fluid supply source; a throttle provided in the middle of the second passage; and an internal passage inlet hole connecting the internal passage of the internal rod and the second cylinder chamber; a nozzle connecting the internal passage of the internal rod and the drain chamber and provided at the tip of the internal rod; a flapper member having one end face facing the nozzle and movable in the axial direction of the piston; In a digital input type hydraulic piston position control device including a flapper member moving means for moving a flapper member, the flapper member moving means is mechanically coupled to the flapper member for moving the flapper member in an axial direction. an intermediate shaft, a pin protruding from the intermediate shaft in a radial direction, a digital rotation drive section, and a rotary plate fixed to the rotation shaft of the digital rotation drive section;
a buffer spring consisting of a tension spring whose one end is fixed to one point on the rotary plate and the other end is fixed to the pin, and which biases the pin in a direction in which the flapper member is biased toward the nozzle; and rotation of the buffer spring. It is characterized by comprising a stopper pin that protrudes from the rotary plate and intersects with the pin at a position that prevents the pin from approaching within a certain limit to the fixing point to the plate, and functions as a stopper against rotational movement of the pin. Digital input type fluid pressure piston position control device. (2) The digital input type fluid pressure piston position control device according to claim (1), wherein the surface of the flapper member facing the nozzle is flat. (3) The digital input type fluid pressure piston position control device according to claim 1, wherein the surface of the flapper member facing the nozzle is a rotary flapper. (4) Utility model registration claim No. (1) characterized in that the flapper member is a rotating bearing.
The digital input type fluid pressure piston position control device described in 2.