JPH082483Y2 - Rack and pinion type rotary actuator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rack and pinion type rotary actuator.

Conventional technology and its problems In a rack and pinion type rotary actuator, generally, double-acting type pistons that slide in cylinders arranged on both sides of the pinion are equipped with a rack that meshes with the pinion, and the rack is driven by fluid pressure. The reciprocating linear motion of the piston is converted into the rotary motion of the pinion that meshes with the rack.

A conventional rack and pinion type rotary actuator has a pinion (101), as shown in a longitudinal section in FIG.
The cylinders (102a) and (102
b) and the piston (103 that slides in the cylinder)
a) and (103b). Piston (103a), (103
In b), a rack (104a) that meshes with the pinion (101),
(104b) is integrally fixed. Both ends of each cylinder are closed by cylinder heads (109) and (110) to form forward pressure chambers (105a) and (105b) and backward pressure chambers (106a) and (106b). Each piston (103
Adjustment screws (114) for adjusting the strokes of these pistons are provided in the cylinder heads facing the ends of a) and (103b). Pressure chamber (105a), (106a)
The cylinder head facing the
2) and (113) are provided. Passages (107) and (108) are formed in the cylinder head and the cylinder body (111), and (112) is (105b) and (113) is (106b).
Is in communication with.

The ports (112), (113) are each connected to a pressure fluid supply source. When pressure fluid is introduced through port (112),
The fluid pressure acts on the forward pressure chamber (105a) and also on the forward pressure chamber (105b) through the passage (107) to move the pistons (103a) and (103b) in mutually opposite directions. At this time, the fluid in each cylinder is discharged to the outside from the port (113). The pinion (101) meshing with the rack is rotated as the pistons move. Next, when the pressure fluid is introduced from the port (113), the pressure fluid acts on the return pressure chamber (106a) and also on the forward movement pressure chamber (106b) via the passage (108). The respective pistons (103b) and (103a) are moved in opposite directions, and the pinion (101) rotates in the opposite direction to the front and returns to the initial state. In this manner, the supply and discharge of the pressure fluid are alternately performed at the ports (112) and (113), so that the pinion repeats the reciprocating rotary motion between the two positions.

As described above, in the conventional rack and pinion type rotary actuator, the two pistons only move equidistantly in the opposite directions with the rack.
The rotation stop positions of the pinion and its output shaft were only two positions corresponding to the reciprocating positions of both pistons.

However, in various robots, automated machines and facilities, three or four rotation stop positions of the output shaft are required due to various operations such as work distribution, valve full opening, half opening, and closing. Since the conventional rack and pinion type rotary actuator has only two rotation stop positions of the output shaft as described above, it cannot meet this demand.

An object of the present invention is to provide a rack and pinion type rotary actuator having three or four rotation stop positions of a pinion and its output shaft in order to meet the above-mentioned demands of the rack and pinion type rotary actuator of the above-mentioned type. It is in.

Means for Solving the Problems The above-mentioned object of the present invention is a rack-and-pinion type in which a double-acting piston that slides in a cylinder arranged on each side of a pinion is equipped with a rack that meshes with the pinion. In a rotary actuator, a rack in one cylinder is fixedly coupled to a piston in the cylinder, and a rack in the other cylinder slides on a piston in the other cylinder on a sliding length of the piston in the one cylinder. A rack and pinion type rotary actuator, which is mounted on the other piston so as to be movable in a shorter range, and has independent working fluid ports provided at both ends of each cylinder. Achieved by As the working fluid of the piston, a gas such as air, a liquid or the like can be appropriately used.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view schematically showing an embodiment of a rack and pinion type rotary actuator according to the present invention.

In this rack and pinion type rotary actuator, the cylinders (2a), (2
b) are arranged in parallel, and pistons (3a) and (3b) slide in cylinders (2a) and (2b), respectively. A rack (5b) is integrally fixed to the piston (3b) shown on the lower side in the figure and meshes with the pinion (1). A sleeve (4) is fitted to the upper piston (3a) so as to be slidable along a side portion of the piston within a certain range, and a rack (5a) is formed on a lower surface of the sleeve, and a pinion (1) is formed. Meshes with.

The sliding range is effective for these racks so that the pinion (1) does not come off the racks (5a) and (5b) during the movement of the piston (3a) and the sleeve (4) described in detail below. The range is shorter than the length. The piston (3b) and the sleeve (4) are prevented from rotating around their axes with respect to the cylinders (2a) and (2b) by the engagement of the rack and the pinion. In this example, cylinder (2a) is
b) has a larger diameter. Pressure chambers (15), (16) and (17), (18) are formed at the end of each cylinder. Ports (11) and (12) are provided in the cylinder head portion facing the pressure chambers (15) and (16), and the pressure chamber (1
Port (1) on the cylinder head facing 7) and (18)
3) and (14) are provided. The cylinder head of the cylinder (2a) is provided with adjusting screws (9) and (10) for adjusting the stroke of the piston (3a), and the piston (3a) facing the tip of the adjusting screw. A cushioning cushion material (19) is attached to each of the head portions. A cushion material (20) is mounted inside both ends of the piston (3a) to cushion the sleeve (4) when sliding.
Each of the pistons (3a), (3b) is provided with a sealing ring (21) at a portion in contact with the inner wall of the cylinder at both ends. In this example, the piston (3a) can be separated into two at the center in the longitudinal direction, and is connected by a concave portion and a convex portion formed on end faces facing each other.
However, since the pressing force by the working fluid always acts between both parts, the connection may be loose.

2a to 2e show the steps of the operation cycle of the above embodiment in sequence. The vertical section of the rotary actuator is shown on the upper side of each figure, and the pinion (1) is on the lower side.
The rotational position of the output shaft coupled to is indicated by the key. First, in the state of FIG. 2a, fluid pressure is applied to each cylinder from the ports (12) and (14), and the ports (11) and (13) are set in a state in which fluid can freely flow in and out. In this example, the fluid pressure acting on each port is made equal. This keeps the piston (3a) in the position shown in the figure, and the piston (3b) slides to the left in the figure. The pinion (1) is rotated to the right in the figure by the rack (5b) integrally attached to the piston (3b). Along with this, the sleeve (4) in the cylinder (2a)
Slides to the right due to the engagement between the rack (5a) and the pinion (1), and comes into contact with the cushioning cushion (20) provided at the end of the piston (3a). This state is shown in FIG. 2b. After the contact, the fluid pressure from the port (14) acts on the piston (3a) via the piston (3b), the pinion (1) and the sleeve (4), but the piston (3a) is generated from the piston (3b). Since the diameter is increased, the total pressure of the piston (3a) is larger under the action of the same fluid pressure, so that the piston (3b) does not move, and the pinion (1) and the piston (3a) also come into contact with each other. Stop at the contact point. Next, in the state shown in FIG. 2b, fluid pressure is applied to the respective cylinders from the ports (11) and (14), and fluid is allowed to enter and leave the other ports. As a result, the piston (3a) slides to the right along with the sleeve (4), the piston (3b) moves to the left, and the pinion (1) is further moved to the right with them. Rotate.
The piston (3a) comes into contact with the adjusting screw (10) at the end of the cylinder (2a) and stops, whereby the pinion (1) is stopped.
Also, the piston (3b) stops (state shown in FIG. 2c). Subsequently, in the state shown in FIG. 2c, fluid pressure is applied to the respective cylinders from the ports (11) and (13), and the other ports are set in a state in which fluid can freely flow in and out. This causes the piston (3b) to move to the right. Due to this movement, the pinion (1) rotates counterclockwise to the left, and the rotation is transmitted to the sleeve (4) via the rack (5a), and the sleeve (4) moves to buffer the piston (3a). Abut on the cushion (20). Also at this time, the piston (3a) does not move due to the difference in total pressure due to the difference in diameter between the piston (3a) and the piston (3b), and the sleeve (4), the pinion (1) and the piston (3b) also move. , Stop at the contact position,
It will be in the position shown in Figure 2d. Further, in the state shown in FIG. 2d, fluid pressure is applied to each cylinder from the ports (12) and (13), and the other ports are in a state in which fluid can freely flow in and out. As a result, the piston (3a) slides to the left along with the sleeve (4), the piston (3b) moves to the right, and the pinion (1) is further moved to the left along with them. Rotate. The piston (3a) comes into contact with the adjusting screw (9) at the end of the cylinder (2a) and stops, so that the pinion (1) and the piston (3b) also stop (state in FIG. 2e). This returns to the state of FIG. 2a.

In the above example, the case where each step is traced from FIG. 2a to FIG. 2e is shown, but the reverse operation can be performed by reversing the order of applying the fluid pressure to the port. Also, 2a
By applying fluid pressure to the ports (11) and (14) from the state shown in the figure and leaving other ports free for fluid flow, the state shown in Fig. 2c can be immediately entered, and vice versa. Is also possible. Also ports (13) and (14)
If a valve that can prevent the inflow and outflow of fluid is installed in the
In the state shown in FIG. 2b, both valves are closed, the port (12) is allowed to enter and leave the fluid, and fluid pressure is applied to the port (11), so that the state shown in FIG.

One or both of the ports of the cylinder on the side where the movable rack is provided may be provided with an opening / closing valve instead of the connection to the pressure fluid supply source as in the above example.
Explaining the case where the port (12) is replaced with an opening / closing valve in the above example, first, in FIG. 2a, the valve of the port (12) is closed, fluid pressure is applied to the port (14), and other The port is in a state in which fluid can freely enter and leave. As a result, the piston (3b) moves to the left in the figure, and the sleeve (4) contacts the right end of the piston (3a). Since the pressure chamber (16) with the port (12) closed acts against the pressure acting on the piston (3a) in this state, the piston (3a) does not move and the state shown in FIG. Become. Subsequently, in FIG. 2b, the valve of the port (12) is opened, fluid pressure is applied to the port (14), and the other ports are allowed to enter and leave the fluid. When the valve is opened, the pressure for stopping the movement of the piston (3a) disappears, so that the piston (3b) further moves to the left and the second c
It becomes the state of the figure. In Fig. 2c, when the valve of the port (12) is opened, the fluid of the port (14) can be freely moved in and out, and when the fluid pressure is applied from the ports (11) and (13), the piston (3b) is released. Move to the right in the figure. Due to the difference in total pressure due to the difference in piston diameter, the piston (3a) remains stopped, the sleeve (4) slides to the left, and comes into contact with the cushion at the left end of the piston (3a) to stop. Yes (state of Figure 2d). When the port (11) is also replaced with the on-off valve, the on-off valve is closed during this operation. In Figure 2d,
Fluid is allowed to enter and leave the ports (11) and (14), the valve of the port (12) is opened, and fluid pressure is applied from the port (13). As a result, the piston (3b) moves further to the right and the piston (3a) moves to the left (state of FIG. 2e), and returns to the initial state.

In the case of using such an on-off valve, it is desirable that the fluid enclosed in the pressure chamber does not cause a volume change due to the applied pressure, and therefore it is desirable to use a liquid as the working fluid.

In the above-mentioned example, the rack (5a) is formed on the sleeve (4), but instead of this, a ring or basket loosely fitted to the piston (3a) is coupled to the plate-shaped rack and the rack (5a) is mounted on the piston (3a). It is possible to adopt an appropriate structure such that the piston (3a) can slide on the piston (3a).

Also, in the example above, the piston (3a) is
b) It has a larger diameter, but if the fluid pressure from the port is made to act more strongly on the piston (3a) and the total pressure of the piston is larger than the total pressure of the piston (3b), the same as above. The effect can be obtained, and in this case, the diameters of both pistons can be the same or the sizes can be reversed. Even when the opening / closing valves are provided in the ports (11) and (12), the diameters of both pistons can be freely determined in the same manner.

Also, in the example above, the piston (3a) is
Since the distance moved in (a) and the distance the sleeve (4) slides on the piston (3a) are equal, the rotational position of the pinion (1) is shown in FIGS. 2b and 2d. The same applies, and the rotation stop positions of the pinion (1) are three. However, the distance the piston (3a) moves within the cylinder (2a) and the sleeve (4)
When the distance to move up is different, the rotation stop position of the pinion (1) is different in both states of Fig. 2b and Fig. 2d, and there are four rotation stop positions of the pinion (1). Becomes

The moving distance of the piston (3a) is the adjustment screw (9), (1
It can be adjusted by changing the amount of protrusion of 0) into the cylinder. Further, if both ends of the piston (3a) are screwed to the central part and the amount of screwing is changed so that the piston (3a) can move in the axial direction, the sleeve (4) on the piston (3a).
The sliding distance can be adjustable.

The position of the piston (3b) can be detected by attaching a magnet to the piston (3b) and providing a magnet detecting device on the cylinder (2b). Based on this, the pinion (1) can be detected. You can

As is apparent from the above, according to the present invention, of the cylinders on both sides of the pinion, the piston in one of the cylinders is equipped with a slidable rack, and ports for each cylinder are provided independently. As a result, it is possible to provide a rack and pinion type rotary actuator having three to four rotation stop positions of the pinion and its output shaft.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a rack and pinion type rotary actuator according to one embodiment of the present invention, FIG. 2a, FIG. 2b, and FIG.
2c, 2d and 2e are longitudinal sectional views showing the operation cycle of the embodiment shown in FIG. 1, and FIG. 3 is a longitudinal sectional view of a conventional rack and pinion type rotary actuator. (1), (101) ... pinion (2a), (2b), (102a), (102b) ... cylinder (3a), (3b), (103a), (103b) ... piston (4) ... … Sleeve (5a), (5b), (104a), (104b) …… Rack (6) …… Main body (7), (8), (109), (110) …… Cylinder head (9), ( 10), (114) …… Adjusting screws (11), (12), (13), (14) …… Ports (15), (16), (17), (18) …… Pressure chamber (19) , (20) …… Cushion cushioning material (21) …… Ceiling ring

Claims (4)

[Scope of utility model registration request] 1. A rack and pinion type rotary actuator in which double acting pistons, which slide in cylinders arranged on both sides of a pinion, are fitted with racks meshing with the pinion. Is fixedly connected to a piston in the cylinder so that the rack in the other cylinder can move on the piston in the other cylinder within a range shorter than the sliding length of the piston in the one cylinder. A rack and pinion type rotary actuator, which is mounted on the other piston, and has independent working fluid ports provided at both ends of each cylinder. 2. The rack according to claim 1, wherein a moving distance of the rack on the piston in the other cylinder is equal to a sliding distance of the piston in the other cylinder. -Pinion type rotary actuator. 3. The rack according to claim 1, wherein a moving distance of the rack on the piston in the other cylinder is different from a sliding distance of the piston in the other cylinder. Pinion type rotary actuator. 4. The rack and pinion type rotary actuator according to claim 1, wherein an inner diameter of the one cylinder is smaller than an inner diameter of the other cylinder.