JPS6238583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary valve for a double-acting hydraulic vibration actuator.

As shown in Fig. 1, a double-acting hydraulic vibration actuator is composed of a cylinder 1 and a piston 4 that divides the inside of the cylinder 1 into two oil chambers 2 and 3, and is actuated alternately into the oil chambers 2 and 3. The cylinder 1 and piston 4 are operated relative to each other by supplying and discharging oil. The supply and discharge of hydraulic oil to the two oil chambers 2 and 3 of the hydraulic vibration actuator is controlled by oil passages 5 and 6, high pressure oil passage 7, and tank oil passage connected to both oil chambers 2 and 3 of the hydraulic vibration actuator, respectively. 8, the switching state connects one oil chamber 2 and high pressure oil passage 7 of the hydraulic vibration actuator and connects the other oil chamber 3 and tank oil passage 8, and the other oil passage 3 and high pressure oil This is accomplished by a continuously rotating rotary valve 9 that alternately connects the oil chamber 2 and the tank oil path 8 while connecting the oil chamber 2 and the tank oil path 8. The rotary valve 9 is rotationally driven by a hydraulic motor 10, so that both oil chambers 2 and 3 of the hydraulic actuator are alternately connected to a high-pressure oil line 7 and a tank oil line 8, so that the cylinder 1 and piston 4 are relatively connected to each other. Vibrate. The hydraulic vibration actuator vibrates the member 12 by connecting the cylinder 1 directly or the piston 4 to the member 12 via the piston rod 11. The figure shows an example in which the piston 4 is connected to a member 12 via a piston rod 11. In this case, the cylinder 1 has a sufficiently large mass so that the relative vibrations between the cylinder 1 and the piston 4 are effectively transmitted to the member 12.

FIG. 2 shows an embodiment of a conventionally used rotary valve, in which a valve sleeve 22 is fitted into a valve body 21, and a valve rotor 23 is fitted into this valve sleeve 22 so as to be rotatable. The valve rotor 23 is provided with two lands 24 and 25 spaced apart in the axial direction, and the lands 24 and 25 allow the space defined by the valve sleeve 22 and the valve body 21 to be divided into left and right tank chambers 26, 27 and a central high pressure chamber 28. The left and right tank chambers 26 and 27 are connected to the tank oil passage 8 through ports 29 and 30 provided in the valve body 21, and the high pressure chamber 28 is connected to the valve sleeve 2.
Port 31 of 2, annular groove 32 of the valve body, port 3
It is connected to the high pressure oil passage 9 through 3. Ports 34 and 35 are provided on the valve sleeve 22 on which the left and right lands 24 and 25 of the valve rotor 23 slide, and these ports 34 and 35 are connected to annular grooves 36 and 37 provided in the valve body 21, respectively. and port 3
8 and 39 to the oil passages 5 and 6 to the hydraulic vibration actuator. The ports 31, 34, 35 of the valve sleeve 22 are arranged at equal intervals in the circumferential direction.
4 and 35, four corresponding ports are respectively arranged at positions along the axis. Four discharge grooves 40 and 41 are provided on the outer surfaces of the left and right lands 24 and 25 of the valve rotor 23, respectively, and are parallel to the rotational axis of the valve rotor 23 and spaced apart from each other by 90 degrees. , these discharge grooves 40 and 41 are connected to left and right tank chambers 26 and 27, respectively. The discharge grooves 40 and 41 provided in each land portion 24 and 25 are offset from each other at an angle of 45° about the axis of rotation of the valve rotor 23. Land portion 24
A supply groove 42 is provided at an interval of 45° from each discharge groove 40, and these four supply grooves 42 are connected to the high pressure chamber 28. Also, the land portion 25
A supply groove 43 is provided at an interval of 45 degrees from each discharge groove 41, and these four supply grooves 43 are connected to the high pressure chamber 28. The valve rotor 23 is rotatable in the direction A within the valve sleeve 22, and the rotation of the valve rotor 23 in the direction A causes the port 34 of the valve sleeve 22 to move between the supply groove 42 and the discharge groove 40.
The ports 35 of the valve sleeve 22 are alternately connected to the discharge groove 41 and the supply groove 43. To explain this connection state, the rotational position of the valve rotor 23 where the port 34 of the valve sleeve 22 is connected to the supply groove 42 (hereinafter referred to as the port 34 supply connection position), and the valve rotor 23 where the port 35 of the valve sleeve 22 is connected to the discharge groove 41. (hereinafter referred to as the port 35 discharge connection position), the rotation position of the valve rotor 23 where the port 34 is connected to the discharge groove 40 (hereinafter referred to as the port 34 discharge connection position), and the valve where the port 35 is connected to the supply groove 43. The rotational position of the rotor 23 (hereinafter referred to as the port 35 supply connection position), the valve where the port 34 is shut off from the supply groove 42 The rotational position of the rotor 23 (hereinafter referred to as the port 34 supply cutoff position), the valve where the port 35 is shut off from the discharge groove 41 Rotor 23 rotation position (hereinafter referred to as port 35 discharge blocking position),
and the rotational position of the valve rotor 23 where the port 34 is blocked from the discharge groove 40 (hereinafter referred to as the port 34 discharge blocking position) and the rotational position of the valve rotor 23 where the port 35 is blocked from the supply groove 43 (hereinafter referred to as the port 34 discharge blocking position).
(referred to as the supply cutoff position) are set to be the same in each case. That is, port 34 and port 3
The relationship among the discharge cutoff position, supply cutoff position, discharge connection position, and supply connection position of No. 5 is as shown in FIG.
In Fig. 3, the rotation angle of the valve rotor 23 is plotted on the horizontal axis.
The connection area to the high pressure chamber 28 is shown in the positive direction of the vertical axis, and the connection area to the tank chamber 26 or 27 is shown in the negative direction of the vertical axis, and symbols for connection ports 34 and 35 are attached in the figure. In this state, the discharge connection position of port 34 and the supply connection position of port 35, the discharge cutoff position of port 34 and the supply cutoff position of port 35, the supply connection position of port 34 and the discharge connection position of port 35, and the The supply cutoff position and the discharge cutoff position of the port 35 are located on the same rotation angle of the valve rotor 23, respectively. The rotary valve 9 is rotated by a hydraulic motor 10 to connect the oil chamber 2 and the high-pressure oil path 7, and to connect the oil chamber 3 and the tank oil path, and to connect the oil chamber 3 and the high-pressure oil path 7. At the same time, the switching state of connecting the oil chamber 2 and the tank oil passage is repeated, and in the former switching state, the piston 4 of the hydraulic vibration actuator is driven in the direction of the oil chamber 3, and in the latter switching state, the piston 4 is driven in the direction of the oil chamber 2. be done. As a result, the piston 4: (1) Drives in the oil chamber 3 direction (2) Stops at the end of the stroke in the oil chamber 3 direction (3) Drives in the oil chamber 2 direction (4) At the stroke end in the oil chamber 2 direction The relative movement with the cylinder 1 is repeated, with the stop of the cylinder 1 as one cycle. However, 2 out of 1 cycle above
and 4, the oil chamber 3 in the direction of movement of the piston 4 moves with considerable inertia.
The piston 4 is stopped by so-called meter-out control that limits the discharge of hydraulic oil from the oil chamber 3 or 2 in the direction of movement of the piston 4. In other words, the port 35 or port 34 in the rotary valve 9
The movement of the piston 4 does not stop when the discharge is shut off, but stops after moving a certain amount due to the inertia of the piston 4 and the compressibility of the hydraulic oil in the oil chamber 3 or 2. Therefore, in the case of a conventional rotary valve in which the discharge cutoff position of the port 35 and the supply cutoff position of the port 34, and the discharge cutoff position of the port 34 and the supply cutoff position of the port 35 are performed at the same time, the piston When stopping at each stroke end of 4, the oil pressure in the oil chamber 2 or 3 on the opposite side from the stroke end becomes negative pressure, causing cavitation. The occurrence of cavitation has been a cause of a decrease in efficiency of the hydraulic vibration actuator.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a rotary valve that can prevent cavitation as much as possible at each stroke end of a piston in a hydraulic vibration actuator.

Embodiments of the present invention will be described in detail below with reference to FIG. 4 and subsequent figures. The symbols and terms used in the description of the conventional example have the same parts and the same meanings in the following description as well.

(First Embodiment) The rotary valve of the present invention has basically the same structure as the conventional example shown in FIG. 2, but the rotary valve in FIG. The supply connection position of port 35, the discharge cutoff position of port 34 and the supply cutoff position of port 35, the supply connection position of port 34 and the discharge connection position of port 35, the supply cutoff position of port 34 and the discharge cutoff position of port 35, respectively. On the same valve rotor rotation angle, the discharge connection position of port 34 is compared to the supply connection position of port 35, and the discharge connection position of port 35 is compared to the discharge connection position of port 34.
The supply cutoff position of the port 34 is retarded relative to the supply connection position of the port 34 and the discharge cutoff position of the port 35, respectively. The connection relationship of the rotary valves in this case is as shown in FIG. Such a connection relationship can be achieved in the rotary valve shown in FIG. 2 by providing supply grooves 42 and 43 bored in the lands 24 and 25 of the valve rotor 23, respectively, at a retarded angle in the direction of rotation.

(Second Embodiment) In this embodiment, the rotary valve of the conventional example shown in FIG. The supply connection position of port 34 and the discharge connection position of port 35, and the supply cutoff position of port 34 and the discharge cutoff position of port 35 are each on the same valve rotor rotation angle. The supply cutoff position of the port 35 is retarded relative to the discharge cutoff position of the port 35, and the supply cutoff position of the port 34 is retarded relative to the discharge cutoff position of the port 35, with other relationships being the same. The connection relationship of the rotary valves in this case is as shown in FIG. Such a connection relationship is the second
This can be achieved by enlarging the supply grooves 42 and 43 formed in the lands 24 and 25 of the valve rotor 23 in the rotational direction of the valve rotor 23 in the illustrated rotary valve.

In both the first and second embodiments of the present invention, in the rotary valve, at least the port 34 is in a supply blocking position relative to the discharge blocking position of the port 34, and the port 34 is in a supply blocking position relative to the discharge blocking position of the port 35. By retarding the shutoff position, one oil chamber 2 or 3 of the hydraulic vibration actuator and the tank oil path 8 are disconnected from the other oil chamber 3 or 2 and the high pressure oil path relative to the valve rotor rotational position where the connection between the other oil chamber 3 or 2 and the tank oil path 8 is severed. Since the rotational position of the valve rotor at which the connection of 7 is cut is retarded, when the piston 4 of the hydraulic vibration actuator stops at each stroke end, the oil pressure in the oil chamber 2 or 3 on the opposite side of the stroke end is reversed. This can prevent cavitation from occurring. Further, in the first and second embodiments of the present invention, one oil chamber 2 of the hydraulic vibration actuator is arranged such that the discharge blocking position of one port 34 or 35 is the discharge connection position of the other port 35 or 34. Or, after ensuring the vibration efficiency of the hydraulic vibration actuator by making the connection to the tank oil line 8 of No. 3 an O-lap, When retarding the supply cutoff position of the port 34, the retardation is set within a range that does not advance the supply connection position of the port 35 with respect to the discharge connection position of the port 34, and the supply cutoff of the port 35 with respect to the discharge cutoff position of the port 34 is performed. At the same time, the retard angle is kept within a range that does not advance the supply connection position of the port 34 relative to the discharge connection position of the port 35. , hold the supply cutoff position of the port 34 at a retard angle or less with respect to the discharge cutoff position of the port 35 (equivalent in the first embodiment, 0° in the second embodiment) with one oil chamber 2 or 3 of the hydraulic vibration actuator. The connection range of the high pressure oil passage 7 is retarded relative to the connection range of the other oil chamber 3 or 2 and the tank oil passage 8. In any case, the rotary valve for a double-acting hydraulic vibration actuator of the present invention connects one of the two oil chambers of the double-acting hydraulic vibration actuator to a high-pressure oil passage, and connects the other oil chamber to a tank oil passage. A valve rotor and a valve that rotatably receives the valve rotor for alternately repeating a switching state in which the two oil chambers are connected and a switching state in which the other of the two oil chambers is connected to a high-pressure oil path and one is connected to a tank oil path. It is a continuously rotating rotary valve consisting of a sleeve, and the connection between the oil chamber of the hydraulic vibration actuator and the high-pressure oil path is disconnected for the valve rotor rotational position where the connection between the oil chamber of the hydraulic vibration actuator and the tank oil path is disconnected. Since the rotational position of the valve rotor is retarded relative to the rotational direction of the valve rotor, cavitation can be prevented from occurring and efficient driving of the hydraulic vibration actuator can be achieved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a control circuit of a hydraulic vibration actuator, Figs. 2 and 3 are explanatory diagrams of a conventional rotary valve for a double-acting hydraulic vibration actuator, and Fig. 4 is an explanatory diagram of a rotary valve of the present invention. FIG. 5 is a diagram illustrating a connection state in another embodiment of the rotary valve of the present invention.

Claims (1)

[Claims] 1 A switching state in which one of the two oil chambers of a double-acting hydraulic vibration actuator is connected to a high-pressure oil path and the other oil chamber is connected to a tank oil path, and the other of the two oil chambers is connected to a high-pressure oil path. A continuously rotating rotary valve consisting of a valve rotor and a valve sleeve rotatably receiving the valve rotor, for alternately repeating a switching state in which one side is connected to a tank oil passage. The rotational position of the valve rotor where the connection between the oil chamber of the hydraulic vibration actuator and the high-pressure oil path is disconnected is retarded relative to the rotational direction of the valve rotor, relative to the rotational position of the valve rotor where the connection between the oil chamber and the tank oil path is disconnected. A rotary valve for a double-acting hydraulic vibration actuator, characterized by: