JPS63251606A - Rotary actuator - Google Patents

Abstract

PURPOSE:To improve the precision in interrupting the output shaft of an actuator by overlapping the valve head of a throttle valve and the open end part of a supply port on each other when the output shaft comes near its stopping point, to restrain oil from flowing into an oil chamber. CONSTITUTION:The ring of a supplementary casing 23 has a supply port 28 and a discharge port 29 and a throttle valve 31 is mounted at the rear end part of an output shaft 21. The sectional areas of a groove 32 and the edge part of a supply port 28 which restrain the flow rate of working oil discharged from a guide passage 10 are narrower than those of a valve body 9 and the open part of the guide passage 10 so that oil flowing on the side of both the groove 32 and the supply port 28 may be restrained. When the output shaft 21 comes near its stopping point, said shaft 21 can be braked sufficiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotary actuator that can brake the output shaft when the output shaft approaches the stop position to reduce the shock when the output shaft comes to a stop. .

[Technical Background of the Invention] The inventor of the present application previously developed a rotary actuator that can stop an output shaft at a position intermediate between its swinging ends. As shown in FIGS. 14 to 16, the rotary actuator according to future development will have an output shaft 2 rotatably disposed within a casing 1,
The inside of the casing 1 is divided into a first hydraulic chamber 5 and a second hydraulic chamber 6 by a rotor 3 formed on the output shaft 2 and a partition 4 attached to the casing l. A first passage 7 communicating with the hydraulic chamber 5 and a second passage 8 communicating with the second hydraulic chamber 6 are formed, and the outer peripheral portion is connected to the first passage 7.
The valve body 9 is formed by cutting out a substantially semicircular shape so as to reach the flow path 7 and the second flow path 8, respectively, and the casing l is provided with:
Four introduction passages 10 extending in the radial direction are formed at equal intervals in the circumferential direction, and ports P3,...P4 of solenoid valves (direction control valves) 11 are connected to each introduction passage lO.
The hydraulic oil is supplied from the introduction passage 10 communicating with the first flow passage 7, while the hydraulic oil is discharged from the introduction passage IO communicating with the second flow passage 8 to drive the output shaft. When the output shaft rotates by 90 degrees, the valve bodies 9 close the introduction passages IO and 1O to stop the output shaft 2.

Such a rotary actuator is connected to port P1. of solenoid valve II.11. ...By sequentially switching P4, the output shaft can be rotated 90' at a time from one swing end to the other and then stopped, making it suitable as a rotational drive mechanism for robot arms, etc. ing.

[Problems to be Solved by the Invention] By the way, when the above-mentioned actuator is used as a rotary drive device for a robot arm, etc., the output shaft is not sufficiently braked when it approaches the stop position, and therefore a large amount of force is generated when the actuator stops. The output shaft may rotate beyond the stop position due to impact force. For this reason, there is a problem that not only is the stopping precision of the output shaft poor, but also vibrations occur in the output shaft, resulting in frequent failures of the robot arm and the like.

[Object of the Invention] This invention was made to solve the above problems, and it is possible to sufficiently brake the output shaft when it comes to a stop, and therefore to improve the stopping accuracy. Needless to say, the object is to provide a rotary actuator that can prevent failures caused by vibrations of the output shaft.

[Means for Solving the Problems] The rotary actuator of the present invention has an oil chamber in the casing, the center of which is eccentric in the radial direction with respect to the axis of the output shaft, and one end on the wall of the oil chamber adjacent to the output shaft. A supply port that opens at one end, and a discharge port that opens at another wall of the oil chamber at one end, are provided on the outer periphery of the output shaft, and when the inlet passage provided in the casing is blocked by the output shaft. A throttle valve with a valve head facing the opening of the supply port is provided, and the area of the gap defined when the valve head and the edge of the opening overlap each other is the area of the inlet passage. The tank port of the directional control valve is formed to be smaller than the area of the gap defined by the opening and the output shaft, and is connected to the inlet passage through which the hydraulic oil is discharged at the end of the supply port. It is configured by connecting.

[Operation] In the rotary actuator configured as described above, when the output shaft approaches the stop position, the valve head of the throttle valve and the opening edge of the supply port overlap. The area of the gap defined at this time is smaller than the area of the gap defined by the overlapping of the output shaft and the opening of the introduction path, so the flow rate of hydraulic oil flowing into the oil chamber is restricted. As a result, the flow rate of the hydraulic oil discharged from the introduction path is restricted, and the output shaft is braked.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 9. 1 to 9 are diagrams showing examples in which the present invention is applied to a swing-type rotary actuator. The rotary actuator shown in these figures differs from the conventional one in that the casing and output shaft are provided with a throttling mechanism that limits the flow rate of hydraulic fluid discharged from the tank port of the solenoid valve. Therefore, in the following description, only the configuration of the squeeze mechanism will be described, and the same components as in the conventional example will be given the same reference numerals and the description thereof will be omitted.

In FIG. 1, reference numeral 20 is a casing, and 21 is an output shaft. The casing 20 is composed of a main body 22 and an auxiliary casing 23. The auxiliary casing 23 is composed of rings 24, 24, a partition plate 25 and a lid 26 arranged between the rings 24, 24. As shown in FIG. 4, the ring 24 is formed with holes 27 opening on both end faces thereof, with the center thereof being eccentric in the radial direction with respect to the axis. The hole 27 has a substantially rectangular cross section, and has an output M on the inner wall facing in the eccentric direction.
A sliding contact portion 27a that contacts the outer peripheral portion of 21 is formed.

The ring 24 also has a supply port 28 with one end opening to the sliding contact portion 27a and the other end opening to the outer periphery, and a hole 27a.
and a discharge port 29 communicating with the outer peripheral portion. One ring 24 is arranged so that its supply port 28 is located parallel to one of the introduction passages 10...
The other ring 24 is attached to the main body 21 with its supply port 28 facing in a direction perpendicular to the supply port 28 of the one ring 24, and the hole 27
A space defined by the partition plate 25 and the partition plate 25 is an oil chamber 30.

On the other hand, two pairs of throttle valves 31 and 31 are provided at the rear end of the output shaft 21.
31 are provided spaced apart from each other in the axial direction. The throttle valve 31 closes the introduction path 10 when the output shaft 21 approaches the stop position and the valve body 9 and the opening of the introduction path IO overlap.
It limits the flow rate of hydraulic oil discharged from the
It is structured as follows. That is, the output shaft 21 has a groove 32 formed by cutting out the outer peripheral portion of the output shaft along the circumferential direction and having a rectangular cross section. The width of the groove 32 is set to be narrower than the inner diameter of the communication hole 28, and the depth of the groove 32 is set to be narrower than the inner diameter of the communication hole 28.
As shown in FIGS. 8 and 9, the gap defined by the groove 32 and the edge of the supply port 28 is gradually deepened from both ends toward the middle portion in the circumferential direction. The area of S is significantly smaller than the area of the gap S defined by the valve body 9 and the opening of the introduction path IO.

The outer periphery between the two grooves 32 is the valve head 31a.
The throttle valve 31 is located in a predetermined range around the valve head 31a. These squeeze valves 31, 31
Of these, the one located on the tip side comes to be located at the center of the opening of the supply port 28 when the introduction path IO.10 facing horizontally in FIG. 2 is closed by the valve body 9. ing. At the end of the supply port 28, the introduction path 1 is provided.
The tank port PT+ of the solenoid valve 11 connected to 0.IO is connected. In addition, when the introduction passage 10-10 is closed by the valve bodies 9 in the vertical direction, the throttle valve 31 located on the rear end side faces the center of the opening of the supply port 28.

The opening of the supply port 28 is connected to the tank port P'Tt of the other solenoid valve 11.

The width of the valve head 31a in the circumferential direction is still the same as that of the supply port 28.
The valve head 31a is set to be slightly narrower than the inner diameter of the supply port 28, and when the valve head 31a is located at the center of the opening of the supply port 28, the valve head 3
A gap S0 is defined between 1a and the edge of the opening (see FIG. 7). Note that the end of the discharge port 29 is connected to a tank (not shown) of a hydraulic pressure generator.

Next, the operation of rotating the output shaft 21 by the rotary actuator as described above will be explained with reference to FIGS. 6 to 9. Figure 2 shows all ports P
, . . . indicate a closed state. here,
Hydraulic oil is introduced through port P4! Make it possible to flow to 0,
The port P3 is brought into a state where hydraulic oil can be discharged from the introduction path IO. Then, the hydraulic oil flows into the second hydraulic chamber 6 through the second flow path 8, and the rotor 3 rotates in the direction of arrow X.

On the other hand, the hydraulic oil in the first hydraulic chamber 5 passes through the first flow path 7 and is discharged from the port P, passes through the tank port PTy of the solenoid valve 11, and is supplied to the oil chamber 30 from the supply 028 on the rear end side. . Then, when the output shaft 21 further rotates,
The valve body 9 and the opening of the introduction path IO overlap (see FIG. 8), and the valve head 3 of the throttle valve 31 corresponding to the supply port 28
1a and the opening of the supply port 28 overlap (see FIG. 9).

In this state, the area of the gap S defined by the edge of the opening and the throttle valve 31 is larger than the area of the gap S defined by the overlapping of the valve body 9 and the opening of the introduction path IO. Since it is small, the flow rate of hydraulic oil flowing through the gap S is significantly restricted.

As a result, the flow rate of the hydraulic fluid discharged from the first hydraulic chamber 5 is restricted, the output shaft 21 is braked, and the output shaft 21 is gradually stopped. Note that the hydraulic oil that has flowed into the oil chamber 30 is
It is returned to the tank of the hydraulic pressure generator through the discharge port 29.

In such a rotary actuator, since the flow rate of the hydraulic oil discharged from the tank port PT is restricted by the throttle valve 31, the output shaft 2
1 can be sufficiently braked when it approaches the stop position, and the impact force at the time of stopping can be alleviated. Therefore, the output shaft 21 does not rotate beyond the stop position, which greatly improves the stopping accuracy, and also prevents equipment failure due to vibration of the output shaft 21. It can be prevented.

Next, FIGS. 10 to 13 are diagrams showing other embodiments of the present invention, and show examples in which the present invention is applied to a rotary type rotary actuator.

In FIG. 10, reference numeral 41 denotes a casing, and an output shaft 42 is rotatably supported by the casing 41 via bearings 43 and 44. Casing 4 of output shaft 42
1, there are two circular eccentric parts 45a,
45b are arranged side by side in the axial direction of the output shaft 42. Note that these eccentric portions 45a and 45b are arranged at equal angles apart in the circumferential direction of the output shaft 42. Furthermore, polygonal (heptagonal in this embodiment) cam rings 47a, 47b are fitted to the outer peripheries of the eccentric parts 45a, 45b via bearings 46a, 46b so as to be relatively rotatable. Note that ring-shaped guide plates 48a, 48b, 49 are installed between the eccentric parts 45a, 45b and the bearings 43, 44, and between the eccentric parts 45a, 45b, respectively, so that the bearings 46a, 46b and the cam ring 47a ,
47b is prevented from coming off from the eccentric parts 45a, 45b.

On the other hand, as shown in FIGS. 11 and 12, a plurality of cylinders 50a and 50b are provided radially at locations corresponding to the eccentric portions 45a and 45b of the casing 41, respectively. These multiple cylinders 50a and 50b are
They are arranged offset from each other in the circumferential direction of the output shaft 42. In addition, plungers 52a and 5 are inserted into the cylinders 50a and 50b via cylinder sleeves 51a and 51b.
2b are each slidably provided. A recess 52c is provided at the outer peripheral end of each of the plungers 52a and 52b, and a spring 53 is provided in each of the recesses 52c.
is inserted. One end of these springs 53 is
A spring cover 54 screwed into the cylinders 50a and 50b is pressed through a spring guide 55. These springs 53 press the inner circumferential ends of the plungers 52a and 52b' against the cam rings 47a and 47b, respectively.

The casing 41 also has a cylinder 50a at one end.
, 50b, and the other end thereof opens on one side of the casing 4I. Furthermore, an auxiliary casing (casing) 58 is fixed to one side of the casing 41 with bolts 59 .

A cylindrical distributor (output shaft) 60 is rotatably inserted into the auxiliary casing 58. This distributor 60 is connected to the output shaft 42 via an Oldham joint 61 and rotates in synchronization with the output shaft 42. Further, the distributor 60 is provided with a first flow path 62 and a second flow path 63, respectively. On the other hand, the auxiliary casing 58 is provided with sub-flow passages 64 and 65 corresponding to the flow passages 56 and 57, respectively. 1. It is configured to communicate intermittently with the second flow path 62,63. The distributor 60 also has a first. Semicircular notches reaching the ends of the second flow paths 62 and 63 are respectively formed, and the wall between the notches serves as the valve body 67. On the other hand, four introduction passages 68 are formed in the auxiliary casing 58 at equal intervals in the circumferential direction, and are located on the same circumference as the valve body 67 and have their axes oriented in the radial direction of the auxiliary casing 58. There is. And the introduction paths 6 facing each other
8 and 68 are closed by the valve body 67 every time the distributor 60 rotates 90 degrees, and the remaining introduction path 68
・68 is the first. They communicate with the second flow paths 62 and 63, respectively. Further, ports of two solenoid valves (directional control valves) 11-11 are connected to the introduction passages 68.... The solenoid valve 11 switches between the first and second flow paths 62 . by appropriately switching its ports.
63, and discharges the hydraulic oil from the other. In addition, the auxiliary casing 5
8, as in the above embodiment, the distributor 6
An oil chamber 70 that is eccentric in the radial direction with respect to 0, and this oil chamber 70
A pair of supply lower 1 and discharge lower 2, which are open to each other, are provided in a pair spaced apart from each other in the axial direction and shifted by 90° in the circumferential direction. On the other hand, the distributor 60 is provided with throttle valves 73, 73 corresponding to the oil chambers 70, 70, respectively. The tank port Py7 of the solenoid valve 11/11 is connected to the supply lower 1/71. PTt are connected to each other.

Next, the operation of the rotary actuator having the above configuration will be explained. First, when hydraulic oil is supplied to the first flow path 62, this hydraulic oil is supplied to the first flow path 62, the sub flow path 64, and the flow path 5.
6 and are sent to cylinders 50a and 50b, respectively. At this time, the hydraulic oil is sent by the distributor 60 to the three cylinders 50a on the left side shown in FIG. 11 among the plurality of cylinders 50a on one side, and the three cylinders 50a on the right side shown in FIG. It is sent to two cylinders 50b.

Note that the plungers 52a and 52b of the cylinders 50a and 50b in the center of both figures are located at the top dead center, respectively. Then, the plungers 52a and 52b in the cylinders 50a and 50b supplied with hydraulic oil move forward and push the cam ring 47a.
, 47b in the counterclockwise direction in FIGS. 11 and 12, thereby rotating the output shaft 4.
2 or rotate in the same direction. As the output shaft 42 rotates, the distributor 60 rotates, whereby the cylinders 50a, 50b to which hydraulic oil is supplied are changed clockwise by one in FIGS. 11 and 12. In other words, 3 to 4 cylinders 50a out of 7 cylinders 50a and 50b are provided corresponding to the eccentric parts 45a and 45b.
, 50b are supplied with hydraulic oil, and the plungers 52a, 52
b moves forward, and the other 4 to 3 cylinders 50a, 50b
The plungers 52a and 52b move back and the hydraulic oil is discharged. The hydraulic oil discharged from the cylinders 50a and 50b is transferred to the flow path 57, the sub flow path 65, and the second flow path 65.
It flows through the flow path 63 and is discharged to the solenoid valve 69,
It flows into the supply lower 1 from the tank port Pr. and,
The valve body 67 and the opening of the introduction passage 68 overlap, and the valve head 73a of the throttle valve 73 and the opening of the supply lower 1 overlap, so that the flow rate of the hydraulic oil is restricted and the output shaft 42 is braked.

In this manner, the output shaft 42 can be sufficiently braked even in the above-mentioned rotary rotary actuator, and the same effects as in the embodiment described above can be obtained.

[Effects of the Invention] As explained above, in the rotary actuator of the present invention, the casing has an oil chamber whose center is eccentric in the radial direction with respect to the axis of the output shaft, and a wall portion of the oil chamber close to the output shaft. A supply port which opens at one end and a discharge port which opens at one end into the other wall of the oil chamber are provided, and an inlet passage provided in the casing is provided on the outer periphery of the output shaft and is blocked by the output shaft. Sometimes a squeeze valve is provided with the valve head facing the opening of the supply port,
In this throttle valve, the area of the gap defined when the valve head and the edge of the opening overlap each other is smaller than the area of the gap defined by the opening of the introduction path and the output shaft. The tank port of the directional control valve, which is connected to the introduction path through which the hydraulic oil is discharged, is connected to the end of the supply port, so when the output shaft stops, this Therefore, not only can stopping accuracy be improved, but also effects such as being able to prevent failures due to vibration of the output shaft can be obtained.

[Brief explanation of drawings]

1 to 9 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a side sectional view showing a rotary actuator, and FIG. 2 is a sectional view 3 taken along the line ■-■ in FIG. 1. The figure is the first
I[I-[[emphasized sectional view, Fig. 4 is IV- of Fig. 1]
Figure 5 is a cross-sectional view taken along the line IV in Figure 1. Figure 6 is an enlarged view of Figure 2 showing details of the introduction passage and valve body. Figure 7 is the communication hole and throttle valve. An enlarged view of Figure 5 showing details of
FIG. 8 is a diagram showing the state immediately before reaching the state shown in FIG. 6;
FIG. 9 is a diagram showing the state immediately before reaching the state shown in FIG. 7,
10 to 13 are views showing other embodiments of the present invention, in which FIG. 10 is a side sectional view showing the rotary actuator, FIG. 11 is a cross-sectional view with emphasis on cutting-■ in FIG.
FIG. 12 is a cross-sectional view taken along the line ■-■ in FIG. 1θ. FIG. 13 is an emphasized cross-sectional view along the line Fig. 14 is a side sectional view, Fig. 15 is a sectional view focusing on X', /-XV in Fig. 14, and Fig. 16 is a sectional view of the
A cross-sectional view taken along the line XVI-XVI of the figure. 1...Casing, 2...Output shaft, 7
...First flow path, 8...Second flow path, IO
...Introduction path, +1 ... Solenoid valve (directional control valve), 2
0...Casing, 21...Output shaft,
28... Supply port, 29... Discharge port, 3
0... Oil chamber, 31... Throttle valve, 31a
... Valve head, 4I ... Casing, 42
...Output shaft, 58 ...Auxiliary casing (casing), 60
・・・・・・Distributor (output shaft), 62・
...First flow path, 63...Second flow path, 68
...Introduction path, 70...Oil chamber, 71...
...Supply port, 72...Discharge port, 73...
... Squeezing valve, 73a ... Valve head, Pl, ...
・P6・・・Port, PTI, P□・・・・・・
tank port.

Claims (1)

[Claims] A casing, an output shaft rotatably supported within the casing, and a plurality of these casings and output shafts, with hydraulic oil being supplied to one of them and discharging hydraulic oil from the other to achieve the above output. a drive mechanism that rotates a shaft; a first flow path provided on the output shaft and communicating with one of the drive mechanisms; and a second flow path that communicates with another drive mechanism; an introduction path, one of which communicates with the first flow path and the second flow path, and is intermittently closed by an output shaft that is rotated; and a directional control valve with a port connected to an end of the introduction path. In a rotary actuator equipped with
The casing has an oil chamber whose center is eccentric in the radial direction with respect to the axis of the output shaft, a supply port with one end opening in the wall of the oil chamber near the output shaft, and a supply port with one end opening in the oil chamber wall near the output shaft. a discharge port opening in the wall, and a squeeze valve provided on the outer periphery of the output shaft, the valve head of which faces the opening of the supply port when the introduction path is blocked by the output shaft, and the squeeze valve The valve is configured such that the area of the gap defined when the valve head and the edge of the opening overlap each other is smaller than the area of the gap defined by the opening of the introduction path and the output shaft. A rotary actuator characterized in that the tank port of a directional control valve is connected to the end of the supply port and is connected to an introduction path through which hydraulic oil is discharged.