JPH09137876A - Change-over valve device for hydraulic pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a change-over valve device for hydraulic pressure with small torque by miniaturizing a rotation-straight motion conversion mechanism of the change-over valve device for hydraulic pressure to be used for a hydraulic driving device such as a press. SOLUTION: Two two-position/four-port spools 14a, 14b are arranged in a valve body 11 in parallel, and one end is urged to the other end side by a spring 15, and a roller follower 16 is rotatably provided on the other end. A rotary shaft 20 is pivotably supported by a motion conversion device 19 to convert the rotation to the straight motion, a pair of plate cams 22a, 22b are fitted at the prescribed intervals to bring the roller followers 16, 16 on the other end of the spools 14a, 14b. The plate cams 22a, 22b are different in phase so that two spools 14, 14 are alternately changed over while the rotary shaft 20 makes one turn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure switching valve device for use in a fluid pressure drive device such as a press machine which reciprocates a ram at high speed, which is represented by a tarrelet punch press.

[0002]

2. Description of the Related Art In a hydraulic drive system of a press machine such as a turret punch press that reciprocates a ram at high speed, conventionally, a switching valve using a solenoid has been often used, but there is a delay in response. When machining is performed frequently, that is, when one cycle time is shortened to improve productivity, a servo valve is used to increase the speed. However, in the servo valve, since the hydraulic oil is used after being squeezed, the pressure loss becomes large and the efficiency is deteriorated. Further, the servo valve is precise and expensive, so that the cost of the press machine is high.

In order to solve the problem in the case of using this servo valve, there is one in which a mechanism for converting a rotary motion into a linear motion is linked to the switching valve and is driven by a rotary actuator to switch the spool. Proposed. FIG. 7 is a hydraulic circuit diagram of a hydraulic drive system of a press machine when such a switching valve is used. In the figure, 1 is a hydraulic cylinder, 2 is a 3-position 4-port switching valve, 3 is a pressure source such as a pump, 4 is a tank, and the discharge port of the pressure source 3 is connected to the P port of the switching valve 2 for switching. The A and B ports of the valve 2 are connected to the hydraulic cylinder 1 to move the piston 1a of the hydraulic cylinder 1 up and down.

FIG. 8 is a sectional view of an example of the switching valve 2 of FIG. In this switching valve 2, only one spool 5 having three positions and four ports which is not biased by a spring is arranged in the valve body 6, and one end of the spool 5 is linked with a groove cam 7 which is a positive-acting cam. The groove cam 7 is driven by a servo motor (not shown).

FIG. 9 is a sectional view of another example of the switching valve 2 of FIG. When the groove cam is used as shown in FIG. 8, a spring or the like for urging the return stroke of the spool 5 is unnecessary, but the groove cam becomes larger than the plate cam. Therefore, in the example of FIG. 9, a plate cam 9 is arranged at one end of a spool 5 of the same 3 position and 4 port which is biased by a spring 8 and is driven by a servo motor.

[0006]

By the way, with the above-mentioned configuration, one spool valve switches the supply direction of the hydraulic oil to the hydraulic cylinder 1 to switch the vertical movement of the piston 1a. The three-position spool 5 will be used for all strokes. Moreover, as shown in FIG. 10, it is necessary to secure an urging force of the spring 8 that is greater than the fluid reaction force acting near the switching end, and therefore the torque of the servo motor that rotationally drives the cams 7 and 9 becomes large. There is.
Line T1 in FIG. 10 shows the spring force when the 3-position type spool is driven by the cam, and line T2 shows the force that acts on the cam when the 2-position type spool is driven by the cam. T3 represents a fluid reaction force. Further, A on the horizontal axis is the position of the A port, B is the position of the B port, the origin is the neutral point Np, and A-Np is the movement amount of the 2-position type spool.
-B is the movement amount of the 3-position type spool.

In view of the above-mentioned conventional problems, the present invention is a rotary type
An object of the present invention is to provide a switching valve device for hydraulic pressure, which can reduce the linear motion conversion mechanism and can be driven with a small torque.

[0008]

In order to achieve the above object, a hydraulic switching valve device according to a first aspect of the present invention is provided.
The one end side was urged by a spring to move toward the other end side 2
At least a pair of spools having one switching position, a motion converting means for converting a rotary motion into a linear motion in cooperation with each of the other ends of the spools, and a rotation or swing driving actuator connected to the motion converting means. Therefore, the spools are arranged in parallel with each other, and in each of the pair of spools, the operation phase of the motion converting means associated with each spool is different from each other so that the switching operation of the paired spools is opposite to each other. It is characterized by having done.

A hydraulic switching valve device according to a second aspect of the present invention is
As the motion converting means, a cam device having a rotatably supported cam and a follower at the other end of the spool is used, and the plurality of cams are coaxially driven to rotate by the actuator.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that, in the following, the portions common to the conventional ones will be denoted by the common reference numerals, and overlapping description will be omitted. In addition, a plurality of embodiments will be described below, but common portions in each embodiment will be described with common reference numerals.

FIG. 1 is a plan sectional view (A) and a front sectional view (B) of a first embodiment of a hydraulic pressure switching valve device according to the present invention.
2 is a hydraulic circuit diagram of a hydraulic drive system of a press machine using the valve device of FIG. Valve device 10 of the present embodiment
Is mainly composed of a valve body 11 and an operation control section 13 attached to the outside of the casing 12.

The valve body 11 comprises two two-position four-port spools 14a and 14b arranged in parallel in the casing 12 and one end of which is biased by a spring 15 toward the other end. A roller follower 16 is rotatably supported at the other end of each spool 14a, 14b.

On the other hand, the operation control section 13 comprises an electric motor 17, a speed reducer 18 and a motion conversion device 19. The motion converting device 19 is a means for converting a rotary motion into a linear motion, and a single rotary shaft 20 rotationally driven by the electric motor 19 via the speed reducer 18 is rotatably supported in the casing 21.
The plate cams 22a and 22b are mounted at predetermined intervals, and the roller followers 16 and 16 provided at the other ends of the spools 14a and 14b are brought into contact with them. Plate cam 22a,
22b, of course, the installation interval, spool 14a, 1
It corresponds to an interval of 4b. The plate cams 22a and 22b have different cam curve phases as shown in FIG.
While the 0 rotates once, the two spools 14, 14 are alternately switched. A servomotor or the like can be used as the electric motor 17. Plate cam 2
2a and 22b do not have to be completely separated, and even if they are integrated, a pair of cam curves can be formed on the rotary shaft 20.
It may be provided at two positions apart from each other in the axial direction.

As shown in FIG. 2, the discharge port of the pressure source 3 is connected to the P port, the A and B ports are connected to the hydraulic cylinder 1, and the spool 14 is connected by the cams 22a and 22b.
The pistons 1a of the hydraulic cylinder 1 are moved up and down by alternately moving a and 14b.

That is, in the state of FIG. 2, each port is blocked, and from this state, the rotating shaft 20 is rotated by the electric motor 17.
Is rotated clockwise in the figure, the cam curve of one plate cam 22b is in a state of going from the lowest point to the apex, so that the spool 14b is pushed by the plate cam 22b and resists the urging force of the spring 15. Moving to the right in the figure, each port communicates with each other to supply hydraulic oil to the lower chamber of the hydraulic cylinder 1, the piston 1a rises, and hydraulic oil in the upper chamber of the hydraulic cylinder 1 passes through the B port. And return to tank 4. During that time, the plate cam 22a also rotates at the same speed, but since the displacement of the cam curve during this time is zero, the spool 14a does not move, the port block state is maintained, and the hydraulic fluid in the upper chamber of the hydraulic cylinder 1 is kept. It is not supplied and does not prevent the piston 1a from rising. When the rotary shaft 20 further rotates, the displacement direction of the cam curve of the plate cam 22b goes from the apex to the lowest point, and the spool 14b returns to the port block state shown in FIG. No hydraulic oil is supplied to the lower chamber of No. 1.

On the other hand, in the plate cam 22a, the cam curve goes from the lowest point to the apex, and the spool 14a moves rightward in the figure against the urging force of the spring 15 by the cam 22a. The hydraulic oil is supplied to the upper chamber of the hydraulic cylinder 1 so as to communicate with each other, the piston 1a descends, and the hydraulic oil in the lower chamber of the hydraulic cylinder 1 returns to the tank 4 via the B port. The spool 14b does not move after returning to the port block state because the displacement of the cam curve is zero,
The port block state is maintained, hydraulic oil is not supplied to the lower chamber of the hydraulic cylinder 1, and the lowering of the piston 1a is not hindered. This operation is repeated at high speed as the rotary shaft 20 rotates.

That is, in this embodiment, the plate cams 22a, 22a
Distance (lift) for moving spools 14a, 14b with b
Is as short as two positions, and the cams 22a and 22b are correspondingly short.
Has a smaller diameter, and the plate cam can be made smaller than the grooved cam.
Due to these, the motion conversion device 19 is downsized. Further, as shown in FIG. 12, when the two-position type spools 14a and 14b are biased by the spring 15, the fluid reaction force only needs to act on the side of the plate cams 22a and 22b.
The urging force of No. 5 is sufficient to push back the spools 14a and 14b, and compared with the case of using a three-position type spool for the entire stroke, it is also small in size and can be driven with a small torque. There is.

FIG. 3 is a plan sectional view (A) and a front sectional view (B) of a second embodiment of the fluid pressure switching valve device according to the present invention.
It is. The valve device 30 according to the present embodiment includes two spools 32 with three positions and four ports, which are biased by the spring 15 to the valve body 31.
a and 32b are arranged in parallel and used. Other configurations and operations are similar to those of the first embodiment. In this embodiment, the lift of the plate cams 22a and 22b is limited to one side,
Only two positions are used, the neutral position and the switching end on one side.
That is, the 3-position spool is used as the 2-position spool.

FIG. 4 is a plan sectional view of a third embodiment of the fluid pressure switching valve device according to the present invention. The valve device 40 of the present embodiment is similar to the first embodiment in that the spring 1 is attached to the valve body 41.
Two 2-position 4-port spools 14a urged by 5,
14b are arranged in parallel, and the motion conversion device 43 of the operation control unit 42 individually pivots the plate cams 22a and 22b associated with the spools 14a and 14b with the rotary shafts 44 and 44, respectively. Motor 45 and reducer 46 for each 44
Is provided and the two electric motors 45, 45 are synchronously controlled so that the two spools 14a, 14b alternately perform the switching operation. Other configurations and operations are similar to those of the first embodiment.

FIG. 5 is a plan sectional view of a fourth embodiment of a hydraulic pressure switching valve device according to the present invention, and FIG. 6 is a hydraulic circuit diagram of a hydraulic drive device of a press machine using the valve device of FIG. . The valve device 50 of this embodiment uses a pair of two-position two-port spools 52a and 52b biased by the spring 15 on the valve body 51, that is, four spools are arranged in parallel.
During one rotation of 0, the four spools 52a, 52
Two spools 52a, 52 of a, 52b, 52b
Each b is a pair, and one of the pair is for supplying hydraulic oil and the other is for discharging hydraulic oil to perform the switching operation. The motion converting section 54 of the operation control section 53 has four cams 22a, 22a, 22b, 22b attached to one rotary shaft 20. Of course, piston 1 of hydraulic cylinder 1
To stop a, the four spools 52a, 52
All of a, 52b, and 52b are set to the port block state. Other configurations and operations are similar to those of the first embodiment. Although the piping structure inside the valve body 51 is slightly complicated, the spools 52a and 52b may be arranged alternately.

In the embodiments described above, an electric motor such as a servo motor is used as the rotary actuator, but a hydraulic or pneumatic motor,
Alternatively, a swing actuator can be used.

[0022]

As described above, in the hydraulic switching valve device according to the first aspect of the present invention, at least a pair of spools having two switching positions are arranged in parallel with each other so as to convert a rotational motion into a linear motion. Since the motion converting means is operated in a different phase by an actuator for rotation or rocking drive in association with the converting means, the switching operations of the paired spools are made opposite to each other. As described above, there is an effect that a hydraulic pressure switching valve device used in a hydraulic pressure driving device such as a press machine that reciprocates at high speed can be downsized and driven with a small torque.

According to another aspect of the present invention, there is provided a hydraulic pressure switching valve device in which a rotatably supported cam and a cam device having the other end of a spool as a follower are used as motion converting means, and a plurality of cams are coaxially rotated by an actuator. Alternatively, since it is driven to swing, there is an effect that the size can be further reduced.

[Brief description of the drawings]

FIG. 1 is a plan sectional view (A) and a front sectional view (B) of a first embodiment of a fluid pressure switching valve device according to the present invention.

FIG. 2 is a hydraulic circuit diagram of a hydraulic drive system of a press machine using the valve device of FIG.

FIG. 3 is a plan sectional view (A) and a front sectional view (B) of a second embodiment of a fluid pressure switching valve device according to the present invention.

FIG. 4 is a plan cross-sectional view of a third embodiment of a hydraulic pressure switching valve device according to the present invention.

FIG. 5 is a cross-sectional plan view of a fourth embodiment of a hydraulic switching valve device according to the present invention.

6 is a hydraulic circuit diagram of a hydraulic drive system of a press machine using the valve device of FIG.

FIG. 7 is a hydraulic circuit diagram of a hydraulic drive system of a conventional press machine when a 3-position 4-port switching valve is used.

8 is a cross-sectional view of an example of the switching valve of FIG.

9 is a cross-sectional view of another example of the switching valve of FIG.

FIG. 10 is a diagram showing a relationship between a spool position in a switching valve, an acting force on a cam, and a fluid reaction force.

[Explanation of symbols]

1 Hydraulic cylinder 1a Piston 3 Pressure source 10, 30, 40, 50 Valve device 11, 31, 41, 51 Valve main body 12 Casing 13, 42, 53, 54 Operation control part 14a, 14b, 32a, 32b, 52a, 52b Spool 15 Spring 16 Roller follower 17,45 Electric motor 18,46 Reducer 19,43 Motion conversion device 20,44 Rotating shaft 21 Casing 22a, 22b Plate cam

Claims (2)

[Claims] 1. At least a pair of spools having two switching positions, one end side of which is biased by a spring to move toward the other end side, and rotary motion is converted into linear motion in cooperation with each of the other ends of these spools. Motion conversion means, and a rotation or swing drive actuator coupled to the motion conversion means, the spools are arranged in parallel with each other,
In each pair of each spool, the operation phase of the motion converting means associated with each spool is different from each other,
A switching valve device for hydraulic pressure in which switching operations of a pair of spools are opposite to each other. 2. A cam device having a rotatably supported cam and a follower at the other end of the spool is used as the motion converting means, and the plurality of cams are coaxially driven to rotate by the actuator. The switching valve device for hydraulic pressure according to claim 1.