JPH0227521B2 - EKIATSUSHIKIKUDOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device that outputs rotational power of a motor via a worm reducer.

This type of drive device used for opening and closing valves, lifting cargo, etc. includes, for example, a worm wheel for driving an output shaft and a worm shaft having a worm that meshes with the worm wheel inside a base casing. In general, the worm shaft is housed in a subcasing connected to the base casing, and an electric motor for rotationally driving the wormshaft is housed in a unit.

In such drive devices, which are used in situations where it is difficult to provide a cam for switching a limit switch on the output shaft or the driven object driven by this output shaft, the output An output position extracting means is provided for extracting a mechanical displacement corresponding to the operating position of the shaft, and a limit switch for stopping the electric motor is turned on or off based on the displacement extracted by the output position extracting means. I have to. In addition, as a conventional output position extraction means, for example, as shown in Japanese Utility Model Application Publication No. 52-134826, the rotation of a worm shaft that meshes with an output worm wheel and is directly coupled and driven by an electric motor is directly extracted to the outside. It was made in 1986 and
As shown in Japanese Patent No. 162373, there is a limit switch that utilizes the axial elastic movement of a wormshaft to switch a limit switch. That is, in the latter case, the wormshaft is supported so as to be elastically displaceable in the axial direction with respect to the base casing, and the output shaft is prevented from moving when the output shaft reaches a predetermined limit position. When a reaction force is applied, the wormshaft is displaced in the axial direction, and a cam portion provided on the wormshaft switches the limit switch to a motor stop position.

By the way, in order to increase the torque of such a drive device, it is effective to use a hydraulic motor as the motor, but in a drive device equipped with the output position extraction means as described above, the electric motor is simply operated using hydraulic pressure. Simply replacing the motor with a motor will cause various problems such as the following.

First, the type that takes the rotation of the wormshaft directly to the outside and switches the limit means,
Since the rotation speed of the wormshaft is much higher than the rotation speed of the output shaft, the range in which the position of the output shaft can be detected will be extremely narrow unless a special device such as a counter limit switch is used as a limit means. There is a problem with this. That is, if a configuration in which the limit switch is switched by a cam body directly connected to the wormshaft is adopted, the output shaft can only operate slightly during one rotation of the cam body,
In order to enable the limit switch to detect the predetermined operating position of the output shaft, the operating range of the output shaft must be limited to a narrow range. Moreover, with this method, the movement of the wormshaft is directly transmitted to the limit means.
When a hydraulic motor that exhibits high torque is used as the motor, problems arise in that the durability of the limit means is reduced and the reliability is impaired. The hydraulic motor, which exhibits high torque,
It may exhibit extreme behavior when the startup stops, etc.
If the impact is directly transmitted to the limit means, there is a disadvantage that the limit means is likely to break down.

It has a structure in which the wormshaft is held so that it can be elastically displaced in the axial direction, and if high torque is to be transmitted, the elastic member that holds the wormshaft must be strong. This has the disadvantage of being bulky, leading to an increase in the size of the device, and if the elastic member is not sufficiently reinforced, the wormshaft will elastically displace at unnecessary times, resulting in unstable operation. There is a problem.

Further, in an electric motor, it is relatively easy to make the housing and the rotating shaft movable relative to each other in the axial direction, but it is difficult to make such a structure in a hydraulic motor. Therefore, when holding the wormshaft so that it can be elastically displaced in the axial direction, it becomes necessary to interpose a joint between the hydraulic motor and the wormshaft that can absorb the axial displacement, and the structure leading to complications.

Furthermore, a limit means is provided as a means for stopping the hydraulic motor at a predetermined limit position, but its structure is generally a limit valve or a combination of a limit valve and a pilot valve, and this valve is used as an output It is known that the switching is performed using a cam or the like provided on a shaft or a driven object that is biased by the output shaft. Therefore, in order to switch such a valve by displacement of the wormshaft, the valve must be disposed within the base casing in the same way as a conventional electric limit switch. However, the limit valve and the pilot valve tend to be larger than electric limit switches, and the piping connected to the valves lacks flexibility in arrangement compared to electrical lead wires. Therefore, electric limit switches also have the disadvantage of requiring time and effort to assemble and adjust, but when using a valve-type limit means such as the one described above, this problem becomes even more pronounced. This leads to further enlargement of the casing.

Furthermore, in conventional systems, the electric motor is usually attached to a sub-casing, and this sub-casing is connected to the base casing.
If high torque is achieved with this structure, the rigidity of the sub-casing itself will be increased, and
It becomes necessary to increase the strength of the connecting portion between the sub-casing and the base casing, making it difficult to reduce the size and weight. Moreover, as described above, when a limit valve or the like is provided in the base casing and the sub-casing supports the hydraulic motor, the base casing and the sub-casing are connected by hydraulic piping. Therefore, it becomes difficult to assemble and disassemble these two casings.

The present invention has been made in view of these circumstances, and it outputs the rotational power of a motor through a worm shaft and a worm wheel, and also generates mechanical displacement corresponding to the operating position of the output shaft. In a drive device equipped with an output position extraction means for taking out the wormshaft, it is possible not only to convert an electric motor system to a hydraulic motor system, but also to enable the wormshaft and wormwheel to rotate around the base casing and to The hydraulic motor is also held in the base casing while being immovably supported in the direction, and the output position take-out means is fixed to the worm shaft for position detection, and a position where it engages with the position detection worm. A detection worm wheel, a threaded rod connected to the position detection worm wheel at one end and disposed outside the base casing, and a cam body screwed onto the threaded rod. Therefore, it is an object of the present invention to provide a drive device that can eliminate all of the above-mentioned disadvantages.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Worm wheel 2 for driving output shaft 1
A worm shaft 4 having a worm 3 that meshes with the worm wheel 2, and a hydraulic motor 5 that rotationally drives the worm shaft 4 are housed in a casing 6. In addition, casing 6
As shown in FIG. 1, the base casing 6a houses the worm wheel 2 and the worm shaft 3, and the base casing 6a
The base casing 6b is connected to the hydraulic motor 5 and surrounds the hydraulic motor 5, and 6c is a joint between the base casing 6a and the subcasing 6b.

The output shaft 1 is a shaft protruding outward from the lower surface of the base casing 6a, and its base end is supported by the base casing 6a via bearings 7, 7 so as to be rotatable and immovable in the axial direction. It is supported by the wheel shaft 8 so as to be integrally rotatable. The worm wheel 2 is fitted to the outer periphery of the wheel shaft 8 so as to be able to rotate integrally therewith, and is also rotatably and axially movable to the base casing 6a via the bearings 7, 7. It is unsupported (see Figure 2). On the other hand, the wormshaft 4 is disposed in the base casing 6a with its axis perpendicular to the axis of the output shaft 1, and is rotatably moved in the axial direction to the base casing 6a via bearings 9, 9. It is unsupported (see Figure 1). In addition,
One end of the wormshaft 4 projects outside the base casing 6a, and forms a prismatic engagement portion 4a for connecting a rotary lever for manual operation. Reference numeral 11 denotes a cap for protecting the engaging portion which is detachably attached to the base casing 6a. The other end of the wormshaft 4 is connected to the rotation output section 5a of the hydraulic motor 5.
is connected to. As shown in FIG. 1, the hydraulic motor 5 is of a type in which a housing 5c rotates around the axis of a support shaft 5b, and the support shaft 5b is connected to the base casing 6a through a plurality of stud bolts 10. The rotation output portion 5a is fixedly installed and integrally formed on the end face of the housing 5c. Moreover, hydraulic fluid outlet ports 5d and 5e are provided on both ends of the support shaft 5b. FIG. 4 shows the circuit portion mainly disposed within this drive device among the hydraulic circuits for supplying hydraulic fluid to the hydraulic motor 5, and 12 in the figure indicates the opening-side hydraulic fluid introduction. An opening-side motor drive line 14 guides the hydraulic fluid supplied to the port 13 to one hydraulic fluid inlet 5d of the hydraulic motor 5; This is a closing side motor drive system path for leading to the other hydraulic fluid inlet 5e of the hydraulic motor 5. Further, 20 is a limit means for stopping the hydraulic motor 5 at a predetermined position. This limit means 20 is a limit valve 1 inserted in the middle of the opening side motor drive system path 12.
6, and a pilot valve 17 for controlling the opening and closing of the limit valve 16. The limit valve 16 is a switching valve having an open position A and a closed position B.
When high pressure hydraulic fluid is introduced to a, the open position A
On the other hand, when high-pressure hydraulic fluid is introduced into the second pilot chamber 16b, the closed position B returns to the open position A. Specifically, this limit valve 16 is
As shown in FIG. 6, a spool 16f is slidably fitted into a body 16e having a pair of hydraulic fluid inflow and outflow ports 16c and 16d, and the spool 16f is attached to the end of the body 16e. At the open position A where they contact the wall 16g, both the working fluid inflow and outflow ports 16c and 16d communicate with each other, and the spool 16f is connected to the other end wall 1 of the body 16e.
At the closed position B where the hydraulic fluid inflow and outflow ports 16c and 16d come into contact with each other, communication between the two working fluid inflow and outflow ports 16c and 16d is cut off. Further, a first pilot chamber 16a is provided between the spool 16f and the one end wall 16g.
A second pilot chamber 16b is formed between the spool 16f and the other end wall 16h.
This second pilot chamber 16b
A spring 16i biasing toward the open position A is also accommodated therein. And the body 1
6e, a first pilot port 16j communicating with the first pilot chamber 16a, and a pilot port 1 communicating with the second pilot chamber 16b.
6k. Note that the spool 16f
The pressure receiving area for the first pilot chamber 16a and the pressure receiving area for the second pilot chamber 16b are set to be equal. Then, one hydraulic fluid inflow/outflow port 16c of this limit valve 16 is connected to the opening side hydraulic fluid inlet 1 via the starting end side conduit portion 12a of the opening side motor drive line 12.
3, and the other hydraulic fluid inlet/outlet port 16d is communicated with one outlet port 5d of the hydraulic motor 5 via the terminal end pipe section 12b of the opening motor drive line 12. The pilot valve 17 is of a two-position type that can be switched between a first position and a second position, and is normally held at the first position by a spring force. By pressing the tip of the operator 17a toward the valve body 17b and urging the rod 17c in the retracting direction, the valve is switched to the second position. Thus, in the first position of the pilot valve 17, the port 17d and the port 17f communicate with each other, and the port 17e is blocked, and in the second position, the port 17d and the port 17f communicate with each other. Port 17e is in communication, and port 17f is blocked. Then, the second limit valve 16
Connect the pilot port 16k to the pilot pipe 28.
The first pilot port 16j of the limit valve 16 is connected to the port 17d of the pilot valve 17 via a pilot conduit 30. Further, the port 17e of the pilot valve 17 is connected to the starting end side conduit section 12a of the opening side motor drive system path 12 via the pilot conduit 31.
is connected to. Further, one end of a drain pipe 32 is connected to the port 17f of the pilot valve 17. The other end of the drain pipe 32 merges with the case drain 33 of the hydraulic motor 5 and is connected to the opening side motor drive line 12 and the closing side motor drive line 14 via the low pressure search valve 34. There is. The low pressure search valve 34 is connected to the drain pipe line 3.
2 and the case drain 33 are selectively communicated with one of the motor drive lines 12 and 14 on the low pressure side.

The hydraulic fluid introduction ports 13 and 15 are provided in a manifold 18 that is covered with an opening of the base casing 6a, and are connected to each of the motor drive system paths 1.
The starting ends of 2 and 14 are formed within the manifold 18. Further, the two motor drive system paths 12,
A pot 35 is interposed between the starting ends of the pieces 14. The cock 35 is normally closed and is opened when the wormshaft 4 is manually rotated.

The pilot valve 17 made in this way is
The switching is performed based on the mechanical displacement extracted by the output position extraction means 36. The output position extracting means 36 is for extracting a mechanical displacement corresponding to the operating position of the output shaft 1 from the wormshaft 4, and has the following configuration. That is, this output position extracting means 36 has a threaded rod 19 rotatably disposed outside the base casing 6a, on which the cam body 26 is threaded, and the rotational force of the worm shaft 4 is transmitted to the threaded rod 19 by a transmission mechanism. 21, the threaded rod 19 is rotated in synchronization with the worm shaft 4, thereby allowing the cam body 26 to be screwed back and forth. Specifically, the transmission mechanism 21 includes a position detection worm 22 fixed to the outer periphery of the worm shaft 4, and a position detection worm wheel 23 rotatably supported by the base casing 6a and meshed with the position detection worm 22. and the position detection worm wheel 23 provided to penetrate the manifold 18.
and a connecting rod 24 that connects the threaded rod 19 to one end of the threaded rod 19, and the other end of the threaded rod 19 is pivotally connected to the tip of a bracket 25 fixed to the outer surface of the manifold 18. . A nut-shaped cam body 26 is screwed onto the threaded rod 19 so as to be able to move forward and backward while being prevented from rotating by a guide rod 27, and the pilot valve 17 is switched by the cam body 26. In addition,
29 is a threaded rod 1 disposed outside the casing 6.
9, a cover for protecting the cam body 26, the pilot valve 17, etc., and this cover 29 is removably attached to the base casing 6a.

Next, the operation of this drive device will be explained.

First, when the limit valve 16 is held at the open position A and the pilot valve 17 is held at the first position, the opening side motor drive line 12 is in an open state, and the pilot line 30 is connected to the drain line. 32, and the pilot line 31 is in a blocked state.
In this state, when hydraulic fluid is supplied to the opening-side hydraulic fluid inlet 13 from a hydraulic pressure source (not shown) and the closing-side hydraulic fluid inlet 15 is connected to a tank (not shown), the hydraulic fluid is supplied to the hydraulic fluid inlet 13. The high-pressure hydraulic fluid is supplied to one hydraulic fluid inlet 5d of the hydraulic motor 5 through the opening side motor drive line 12, and the housing 5c of the hydraulic motor 5 rotates together with the worm shaft 4. Therefore, the worm wheel 2 meshing with the worm 3 of the worm shaft 4 is driven, and the output shaft 1 rotates at a slow speed in the forward direction. As a result, for example, a valve body (not shown) of a valve (not shown) connected to the output shaft 1 through a mechanism for converting rotational motion into linear motion (a type of valve in which a valve stem supporting the valve body is screwed into a valve body) (in some cases, the valve stem is directly connected to the output shaft 1) moves in the opening direction. In this case, since the threaded rod 19 also rotates in synchronization with the wormshaft 4, the cam body 26 screwed onto the threaded rod 19 moves in the direction of arrow X in response to the movement of the valve body (not shown). . Then, when the valve body (not shown) reaches the maximum open position, the cam body 2
6 reaches the set position α, the cam body 26 presses the operator 17a of the pilot valve 17, and the valve 17 is switched from the first position to the second position shown in FIG. Then, the ports 17d and 17e of the pilot valve 17 are brought into communication, and a portion of the high-pressure hydraulic fluid in the open-side motor drive line 12 is transferred to the casing pipe 31, the ports 17d and 17e of the pilot valve 17, and the pilot pipe. Limit valve 1 through passage 30
6 is supplied to one pilot chamber 16a (pilot port 16j). At this time, the other pilot chamber 16b of the limit valve 16 is connected to the motor drive line 1 on the low pressure side via the pilot pipe 28.
It is connected to 4. Therefore, the spool 16f of the limit valve 16 slides to the right in FIG. 6 against the biasing force of the spring 16i due to the pressure of the hydraulic fluid introduced into the one pilot chamber 16a. Inflow/outflow port 1
Cut off communication between 6c and 16d. That is, the limit valve 16 is switched from the open position A to the closed position B, and the open side motor drive line 12 is cut off. As a result, the supply of hydraulic fluid to the hydraulic motor 5 is cut off, and the hydraulic motor 5 is stopped. The hydraulic fluid that is removed from the pilot chamber 16b when the spool moves to the right flows back through the pilot pipe 28, is discharged to the motor drive line 14 on the low pressure side, and is returned to a tank (not shown).

When the hydraulic motor is stopped in this manner, the pilot valve 17 is regulated by the cam body 26 and maintained at the second position, and one pilot chamber 16a of the limit valve 16 is connected to the pilot conduit 30 and the pilot chamber 16a. It remains in communication with the opening side motor drive line 12 via the ports 17d, 17e of the valve 17 and the pilot line 31. From this state, next, when a hydraulic pressure source is connected to the closing side hydraulic fluid inlet 15 and the opening side hydraulic fluid inlet 13 is connected to a tank (not shown), the inside of the closing side motor drive line 14 is connected. A portion of the introduced high pressure hydraulic fluid is supplied to the other pilot chamber 16b (pilot port 16k) of the worm wheel limit valve 16 through the pilot line 28. As a result, this limit valve 16
The spool 16f slides to the left in FIG. 6 due to the pressure of the hydraulic fluid introduced into the pilot chamber 6b and the biasing force of the spring 16i. 16
d ditto becomes connected again. That is, the limit valve 16 is switched from the closed position B to the open position A. Therefore, the open-side motor drive system path 12 communicating with the tank becomes open. Therefore, the high-pressure hydraulic fluid introduced from the closing-side hydraulic fluid inlet 15 is supplied to the outflow port 5e of the hydraulic motor 5 through the closing-side motor drive line 14, and
The returned working fluid discharged from the inlet 5d of the hydraulic motor 5 is discharged through the opening side motor drive line 12. In this way, the hydraulic motor 5
rotates in the opposite direction, and the valve body (not shown) moves in the closing direction. The hydraulic fluid removed from the pilot chamber 16a when the spool 16f moves to the left flows back through the pilot pipe 30, the ports 17d and 17e of the pilot valve 17, and the pilot pipe 31 to the low pressure side. It is discharged into the motor drive line 12 and returned to a tank (not shown). In this way, when the hydraulic motor 5 reverses, the threaded rod 19 of the output position extraction means 36, which rotates in synchronization with the worm wheel shaft 4, also rotates in the reverse direction, and the cam body 2 screwed onto this threaded rod 19 also rotates in the reverse direction.
6 moves in the opposite direction, that is, to the right in FIG. Therefore, when the hydraulic motor 5 rotates in reverse for a while, the cam body 26 separates from the operator 17a of the pilot valve 17.
This pilot valve 17 switches back to its first position. When the hydraulic motor 5 continues to rotate in reverse, the valve body (not shown) reaches the closed position and comes into contact with the valve seat, and the hydraulic motor 5 stops due to the reaction force. In this case, if the pressure of the hydraulic fluid supplied to the closing side hydraulic fluid inlet 15 is controlled to a constant value by an appropriate means such as using a pressure control valve, the valve body will be able to control the valve with a constant force. Although it is pressed against the seat, the configuration of this control portion has no direct relation to the present invention, and therefore a description thereof will be omitted.

In the above embodiment, the motor is stopped at one of the limit operating positions based on the mechanical displacement taken out by the output position taking means, but the present invention does not necessarily apply to such a thing. Of course, the present invention is not limited to this, and the present invention is also applicable to, for example, a motor in which the motor is stopped at a pair of limit operating positions set at each end of the operating range of the output shaft based on the mechanical displacement. is possible. In this case, a pair of cam bodies may be screwed onto the threaded rod.

Furthermore, the basic configuration of the drive device is of course not limited to that of the illustrated embodiment; for example, a device that converts the rotation of the worm wheel into forward and backward movement of the output shaft is also provided within the casing. It's okay to be hot.

Since the present invention has the above configuration, the following effects can be obtained.

First of all, since we use a hydraulic motor that produces high torque, the range of loads that can be applied to the output shaft can be greatly increased without increasing the size of the device, which is fundamentally important. It has the following characteristics.

In addition, the rotation of the wormshaft is not directly extracted, but is extracted using a position detection worm, a position detection worm wheel, a threaded rod, and a cam body, so special limit means such as a counter limit switch is used. It is possible to set a large detectable range of the position of the output shaft without using. Moreover, if you do this,
Even if the wormshaft, which is directly connected to the high-torque hydraulic motor, exhibits severe behavior, it will not be directly transmitted to the limit means (in the above embodiment, the pilot valve and limit valve), resulting in improved durability and reliability. can be increased.

Moreover, since the wormshaft is no longer held so that it can be elastically displaced, but is instead supported by the base casing in a state where axial movement is prohibited, an elastic support mechanism for holding the wormshaft is not required, and high torque can be achieved. Even if the worm shaft is made larger, there will be no inconveniences such as the base casing housing the elastic support mechanism becoming larger or the wormshaft being unnecessarily elastically displaced and the operation becoming unstable. In this way, there is no need to provide a joint capable of absorbing displacement in the axial direction between the hydraulic motor and the wormshaft, and the structure can be simplified.

Furthermore, since the screw rod of the output position extracting means, the cam body screwed onto the screw rod, and the cam body are arranged outside the base casing, the means for stopping the hydraulic motor at a predetermined operating position ( In the embodiment described above, it is not necessary to arrange the pilot valve and limit valve within the base casing. Therefore, the base casing can be made smaller and lighter than in a case where the pilot valve or the like must be placed inside the base casing, and assembly and adjustment work can be simplified. .

In addition, the base casing not only supports the worm wheel and the wormshaft in an immovable manner in the axial direction, but also holds the hydraulic motor in the base casing, so that all loads are received by the base casing. I have to. Therefore, it is easy to create a structure with high rigidity and excellent strength, and it is also possible to simplify assembly and disassembly operations. Specifically, there is no need to increase the strength of the sub-casing itself that protects the hydraulic motor or the joint portion between this sub-casing and the base casing, and
Since the situation in which these two casings are connected by hydraulic piping can be avoided, assembly work and disassembly work during maintenance and inspection are also facilitated.

As described above, according to the present invention, all of the inconveniences that would be expected when a hydraulic motor is used in a drive device equipped with an output position extraction means can be eliminated, and the drive device can be made small, lightweight, and high in torque. Therefore, it is possible to provide an excellent hydraulic drive device that can perform

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially cutaway plan view, FIG. 2 is a partially cutaway front view,
Fig. 3 is a partially cutaway side view, Fig. 4 is a schematic circuit diagram, Fig. 5 is an explanatory diagram showing the relationship between the cam body and the pilot valve, and Fig. 6 is a cross section showing the internal structure of the limit valve. It is a diagram. 1... Output shaft, 2... Worm wheel, 3...
... Worm, 4 ... Worm shaft, 5 ... Hydraulic motor, 6a ... Base casing, 19 ...
Threaded rod, 21... Transmission mechanism, 22... Worm for position detection, 23... Worm for position detection, 26...
...Cam body, 36...Output position extraction means.

Claims (1)

[Scope of Claims] 1. A worm wheel for driving an output shaft, a worm shaft that engages with this worm wheel via a worm, a motor that rotationally drives this worm shaft, and a machine that corresponds to the operating position of the output shaft. output position extraction means for extracting a target displacement from a wormshaft portion, and the motor is stopped when a predetermined operating position of the output shaft is detected based on the displacement extracted by the output position extraction means. In the drive device, the worm wheel and the worm shaft are supported rotatably and immovably in the axial direction by a base casing that accommodates the worm wheel and the worm shaft, and the motor is supported by a base casing that accommodates the worm wheel and the worm shaft. The output position extracting means is a hydraulic type and is disable to move in the axial direction, and is held in the base casing to output high torque. a position detection worm wheel that meshes with the position detection worm;
A hydraulic drive characterized by comprising a threaded rod having one end connected to the position detection worm wheel and disposed outside the base casing, and a cam body screwed onto the threaded rod. Device.