JPH0450149B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a position indexing device.

(Prior Art) Various structures have been used as devices for positioning a rotary table or the like of a machine tool. For example, a concrete example is the 60's
It is described in Japanese Patent No. 172647, and the configuration of the device is shown in FIG. In the figure, 81 is a hydraulic drive motor, and by this drive motor 81,
An object to be indexed, such as a rotary table, is driven to rotate. A discharge line 82 and a tank line 83 connected to the drive motor 81 are provided with an electromagnetic switching valve 84 for switching between forward and reverse rotation of the drive motor 81.
A contactor 87 is connected to a spool 86 for switching the communication state and adjusting the opening degree of each port in the flow direction control valve 85. There is. This contactor 87 is adapted to come into contact with a cam surface of a cam 88 that is interlocked with the rotation of the drive motor 81. A recess 89 is formed on this cam surface at a location corresponding to the indexing position of the object to be indexed, and as shown in the figure, the contact 87 is provided in this recess 89.
In the position where the spool 86 is inserted, the spool 86 is located at the most extreme position (right end position in the figure),
At this time, the flow rate directional control valve 85 is at the symbol position S1.
, the drive motor 81 is stopped at this indexed position without fluid being supplied to the drive motor 81.

On the other hand, the flow rate direction control valve 85 has a spring chamber 90 and a pilot chamber 91, and the discharge line 82 and tank line 83 are also connected to the spring chamber 90 and the pilot chamber 91 via a switching valve 92. each connected. When this switching valve 92 is switched and pressure fluid is introduced into the pilot chamber 91,
The spool 86 is pushed toward the rear spring chamber, the contact 87 is removed from the recess 89, and the flow direction control valve 85 is positioned at the symbol position S2, thereby switching the internal communication state.
As a result, the working fluid is supplied to the drive motor 81 via the electromagnetic switching valve 84, the drive motor 81 is rotationally driven, and the indexed object is rotated. At the same time, the cam 88 also starts rotating. Then, after a predetermined period of time has elapsed, when the switching valve 92 is returned to the return position,
Thereafter, the pressure fluid in the discharge line 82 will be guided to the spring chamber 90 of the flow direction control valve 85, and the spool 86 will be pushed toward the cam 88 at the tip by this fluid pressure and the spring force, and the contactor 87 presses and contacts the cam surface with this force. That is, the spool 86 responds to the cam surface of the cam 88. In this state, the flow direction control valve 8
5 is located at the symbol position S3, the opening degree is slightly narrowed while maintaining the communication state, and the drive motor 81 continues to rotate at a slightly slower speed than above. and spool 8
When the contactor 87 of No. 6 reaches the position of the recess 89 again and is fitted into the recess 89, the flow direction control valve 85 returns to the symbol position S1, and the supply of pressure fluid to the drive motor 81 is stopped. Then, it stops at this indexed position and completes the position indexing.

In the above process, in the vicinity of the stop position, that is, the index position, the cam 88 is
The cam surface near the concave portion 89 is formed as a tapered portion 93 that gradually moves toward the center, and when the contact 87 moves along this tapered portion 93, the spool 86 gradually moves toward the tip side. However, with this movement, the opening degree of the flow rate directional control valve 85 is gradually narrowed in the state of the symbol position S3, thereby decelerating, and then stopping at the indexed position.

(Problems to be Solved by the Invention) As described above, in the conventional device, the flow rate supplied to the drive motor 81 is gradually reduced in the vicinity of the indexing position, thereby providing deceleration. During this deceleration process, if the supplied flow rate becomes very small, the rotation of the drive motor 81 will no longer follow the controlled flow rate, and therefore a sufficiently smooth stopping operation will not be achieved. There is a problem. The main body of the hydraulic drive motor 81 as described above is housed in a motor case, and within this motor case, the motor main body prevents the working fluid flowing inside from leaking to the motor case side. This leakage fluid (hereinafter referred to as drain) is
The drain port of the motor case is directly connected to the tank to return the water to the tank. The amount of drain depends on the pressure difference between the pressure of the working fluid flowing through the drive motor 81 and the pressure at the drain port, and when the drain port is directly connected to the tank as described above. The above-mentioned differential pressure is also large, and therefore the amount of drain cannot be ignored. As a result, when the flow rate supplied to the drive motor 81 becomes minute and the ratio of the drain amount to the supply flow rate increases, the operation of the drive motor 81 no longer responds to the supply flow rate. It is becoming impossible to obtain controllability when supplying a minute flow rate.

This invention was made in order to solve the above-mentioned conventional problems, and its purpose is to improve controllability particularly when supplying a minute flow rate during the deceleration process, and as a result, to achieve smoother stopping. The object of the present invention is to provide a position indexing device that obtains the desired position.

(Means for Solving the Problems) Therefore, the position indexing device of the present invention has the following features:
A variable orifice 49 is connected to the lines 44, 40, 46, 32 connecting the drive motor 1 to the tank.
In addition to interposing this variable orifice 49,
The position indexing device is configured to decelerate the drive motor 1 by setting it in a small opening state near the index position.
A drain port 60 is connected to the line 44 in front of the variable orifice 49.

(Function) In the above position indexing device, the drain port 6
0 is affected by the pressure on the discharge side of the drive motor 1, but during deceleration, that is, the variable orifice 4
When the opening of the opening 9 is changed to a smaller opening, the pressure on the discharge side increases due to the inertial force of the indexed object 4, for example. Therefore, the pressure difference between the pressure of the working fluid flowing through the drive motor 1 and the drain port 60 is smaller than that of the conventional device in which the drain port is directly connected to the tank. Therefore, the amount of drain based on the reduced pressure difference is reduced compared to the conventional device, and as a result, the ratio of the amount of drain to the working fluid supplied to the drive motor 1 becomes smaller, so when a minute flow rate is supplied. controllability is improved.

(Embodiments) Next, specific embodiments of the position indexing device of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a partially cutaway front view of the position indexing device in one embodiment of the present invention, and in the same figure, 1
is a double-shaft drive motor having low speed and high torque characteristics, such as a trochoid motor or a gear motor, and has a drive gear 3 attached to its upper main shaft 2. The object to be indexed 4 such as a rotary table has a rotating shaft 5
and a gear 6 which is fixed to the rotating shaft 5 and meshes with the driving gear 3, and when the upper main shaft 2 rotates, the driving gear 3, the gear 6, and the rotating shaft 5 are connected to each other. The indexed object 4 can be rotationally driven. In addition, the rotating shaft 5
is configured to be able to move up and down with respect to a base 7 that supports it, and rings 8 and 9 are attached to the upper surface of the base 7 and the lower surface of the indexed object 4, respectively, and the relative relationship between these rings 8 and 9 is Coupling teeth that engage with each other are formed on the facing surfaces. The rotating shaft 5 is moved up and down by a hydraulic cylinder 10.

A cam 1 is attached to the lower main shaft 11 of the drive motor 1.
2 is attached. As shown in FIG.
a flow direction control valve 1 that controls the flow rate and direction of fluid supplied to the drive motor 1 according to the swing of the drive motor 3;
4 constitute a position indexing mechanism. The cam 12 has a substantially disk shape disposed concentrically with the axis of the lower main shaft 11, and its circumferential side is connected to the concentric arc-shaped portion 15 of the lower main shaft 11 and this arc-shaped portion. 1
A substantially tapered portion 1 gradually moving toward the center from 5.
6, and a recess 17 located approximately in the center of the tapered portion 16.
It has two locations. The lever 13 is rotatably supported by the casing 18 at its midpoint, and the tip of an arm 19 that extends downward in the figure from the pivot point is provided with an arm 19 that rolls on the circumferential side of the cam 12. A rotatable roller 20 is rotatably supported. The recess 17 provided in the cam 12 has a shape into which the roller 20 can fit. Also, an arm 21 of the lever 13 that extends upward in the figure
The tip of the spool 22 of the flow direction control valve 14
The rod 23 is integrally formed on the proximal end side of the rod 23,
It is pivotally connected via a pin 24.

Next, the flow direction control valve 14 will be explained with reference to FIG. The flow direction control valve 14 controls the fluid supplied to the drive motor 1 by moving the spool 22.
It has a pump port P connected to a discharge line 31 connected to a hydraulic pump (not shown), a tank port T connected to a tank line 32, and three ports A and B on the secondary side. , M. Further, a spring chamber 34 having a spring 33 is provided at the rear end of the spool 22 (on the right side in FIG. 1). Also, on the opposite side of this spring chamber 34,
A pilot chamber 35 is provided, and when fluid is introduced into the pilot chamber 35, the fluid pressure in the pilot chamber 35 and the spring force of the spring 33 are made to oppose each other. In a neutral state in which the spool 22 moves to the most distal end side, it is located at the symbol position S1, the pump port P communicates with the port A, the tank port T communicates with the port B, and the port M is blocked. On the other hand, in the switching state, symbol positions S2 and S3
Given the communication state shown in the diagram, first spool 2
2 is in the most retracted state, it is located at the symbol position S2, the pump port P communicates with port B, and the tank port T communicates with ports A and M, respectively. In addition, in the process of the spool 22 gradually moving toward the tip side from this state, it is located at the symbol position S3, and at this position, the communication state at the symbol position S2 is maintained, and the spool 22 is moved toward the tip side. The flow path is gradually narrowed as it moves.

The port A of the flow direction control valve 14 is connected to the hydraulic cylinder 1 for vertically moving the indexed object 4.
It is connected by a line 37 to the descending side pressure supply port 36 at 0. On the other hand, port B and port M are connected to the primary side port of an electromagnetic switching valve 38 for switching forward and reverse rotation of the drive motor 1 through lines 39 and 40, respectively. Further, a branch line 41 branched from the line 39 connected to the port M is connected to the hydraulic cylinder 1.
It is connected to the rising side pressure supply port 42 of No. 0. The secondary port of the electromagnetic switching valve 38 is connected to the drive motor 1 through lines 43 and 44.

Note that port M and port T of the flow rate directional control valve 14 are connected by a bypass line 46 with a manual variable throttle 45 interposed therebetween. As described later,
When the indexing position is approached during the indexing operation, the flow rate directional control valve 14 is located at the symbol position S3, and as the spool 22 moves toward the tip side, the supply side communication between ports P and B is established. flow path,
Variable throttles 47 and 48, which are respectively configured in the discharge side communication passages between ports M and T, are configured to gradually reduce their opening degrees. The deceleration of the drive motor 1 at this time is controlled by the flow rate corresponding to the variable throttle 48 in the discharge side communication flow path. However, if the indexed object 4 is changed and the rotational load is changed, for example, it is necessary to adjust the amount of speed change during deceleration in accordance with the rotational load. If the compatibility at that time is impaired, the vehicle may stop before reaching the indexed position, or the vehicle may jump over the indexed position if the indexed position is reached without being sufficiently decelerated. It also happens like this. Therefore, as mentioned above, the throttle 45 is connected in parallel to the variable throttle 48 of the flow direction control valve 14.
By providing and adjusting this aperture 45,
It is possible to easily apply deceleration according to the rotational load of the indexed body 4. Therefore, in the above device, the variable orifice 49 for providing deceleration is provided by the variable throttle 48 and the bypass throttle 45.
It consists of

Furthermore, in the above device, as described later,
In order to start the movement of the spool 22 in the flow direction control valve 14, a switching valve 51 is provided, and the primary ports P and T of this switching valve 51 are provided.
are connected to branch lines 52 and 53 branched from the discharge line 31 and tank line 32, respectively, and the secondary ports A and B are connected to the pilot lines 54 and 55, respectively, of the flow rate directional control valve 14. It is connected to the chamber 35 and the spring chamber 34.

In the above device, the drain port 60 of the drive motor 1 is further connected to the electromagnetic switching valve 3 described above.
8 and this drive motor 1, a line 43,
44 through drain connection lines 61 and 62, respectively, and these drain connection lines 61 and 62 are connected through check valves 63 and 64 in a direction that allows fluid flow from the drain port 60 side. It is set up.

Next, the operating state of the above-mentioned position indexing device will be explained. First, the roller 20 provided on the lever 13
is fitted into the recess 17 of the cam 12, and the drive motor 1
A state in which the is stopped at the indexed position will be explained. In this case, it is assumed that the switching valve 51 is located at the symbol position C2 in FIG. It should be located in a neutral position. In this state, the spool 22 is affected by the force of the spring 33 and the spring chamber 3.
It is pressed toward the distal end side by the fluid pressure in 4. This force is transmitted to the roller 20 via the rod 23 at the tip of the spool 22 and the lever 13, and the roller 20 is fitted into the recess 17 of the cam 12. At this time, the flow rate directional control valve 14
is located at symbol position S1, so the fluid in the discharge line 31 is transmitted from port A through line 37 to the descending pressure port 36 of the hydraulic cylinder 10, and the fluid in the ascending pressure supply port 42 is transmitted through line 41. It is open to the tank line 32, and the indexed body 4 is pushed down, and the coupling teeth provided on the indexed body 4 side and the base 7 side are engaged with each other, and the position is mechanically fixed at the indexed position. The state has been made. On the other hand, since the lines 39 and 40 leading to the drive motor 1 are both open to the tank line 32, no fluid is supplied to the drive motor 1, and the drive motor 1 is held in a stopped state.

When performing position indexing from the above state, first the switching valve 51 is switched to the switching position shown by the symbol position C1 in FIG. By switching the switching valve 51 in this manner, the fluid in the discharge line 31 is guided to the pilot chamber 35 via the pilot line 54, while the spring chamber 34 is
Tank line 32 via pilot line 55
be opened to. The high-pressure fluid thus introduced into the pilot chamber 35 causes the spool 22 to move toward the tip side against the spring force of the spring chamber 34. With this switching movement, the lever 13 rotates and the roller 20 is removed from the recess 17. Furthermore, as a result of the movement of the spool 22 in this way, the flow direction control valve 14 is located at the symbol position S2, and the discharge line 31 is communicated with the port B via the pump port P. At this time, the hydraulic cylinder 10 The fluid in the discharge line 31 is supplied to the rising side pressure supply port 42 of the indexable body 4 through the line 41, and the falling side pressure supply port 36 is opened to the tank line 32 through the line 37. The coupling tooth is lifted up, and the coupling teeth are released from the occlusion and become rotatable. And the above-mentioned object to be indexed 4
The electromagnetic switching valve 38 is set, for example, to the normal rotation position by the unclamping completion signal transmitted upon completion of the lifting operation, and the pressure fluid from the discharge line 31 is transmitted to the drive motor 1 via the lines 39 and 43. Since the discharge side lines 44 and 40 communicate with the tank line 32 via the port M, the drive motor 1 starts rotating rapidly, and as a result, the indexed object 4
is driven in rotation.

Then, after a predetermined period of time has elapsed, the switching valve 51 is returned to the symbol position C2 again. This return operation may be performed by switching the switching valve 51 in response to a signal issued by an angle detector disposed immediately before the indexed position, or by using a timer or the like. When the switching valve 51 is positioned at the symbol position C2 in this way, the discharge line 31 is again placed in the spring chamber 34.
Since the pilot chamber 35 communicates with the tank line 32, the spool 22 moves toward the tip side by the fluid pressure in the spring chamber 34 and the spring force, and attempts to rotate the lever 13. . However, since the arcuate portion 15 of the cam 12 is located at the position of the roller 20 at the tip of the lever 13, the roller 20 contacts this arcuate portion 15 and rolls. As a result, the spool 22 of the flow direction control valve 14 does not move to the most extreme position.
It is located in the middle, that is, at symbol position S3. In this state, the flow path is constricted, so the flow rate of the fluid sent to the drive motor 1 is reduced, and the indexed body 4 is driven at a low speed at the beginning of rotation.

As the drive motor 1 continues to rotate,
The flow path is gradually narrowed by the substantially tapered portion 16 of the cam 12, and the rotational speed of the drive motor 1 is reduced. Thereafter, when the recess 17 of the cam 12 is located at the position of the roller 20, the roller 20 is fitted into the recess 17, and the flow direction control valve 14 is again moved to the neutral position S.
Located at 1. At this time, the fluid pressure supply state to the hydraulic cylinder 10 is reversed, the indexed body 4 is pushed down, and the coupling teeth provided on the indexed body 4 side and the base 7 side are engaged with each other, and the indexed body 4 is pushed down. 4 to the indexed position. At the same time, as described above, the lines 39 and 40 leading to the drive motor 1 are both opened to the tank line 32, so the drive of the drive motor 1 is stopped and the indexing is completed.

In the process of the indexing operation as described above, for example, during forward rotation, working fluid is supplied to the drive motor 1 from the line 43 side in FIG. 1, and fluid is discharged from the drive motor 1 to the line 44 side. Then, the following pressure acts on the drain port 60 of the drive motor 1. That is, the drain port 60 is connected to each of the lines 43 and 44 through drain connection lines 61 and 62, and each of the lines 43 and 44 is connected to a check valve 63,
64, the line pressure on the low pressure side of each of the lines 43 and 44 is the same. For example, at the start of the indexing operation when the flow direction control valve 14 is located at the symbol position S2, and when the roller 20 rolls along the arcuate portion 15 of the cam 12, the flow direction control valve 14 is located at the symbol position S3. During steady rotation in which the drive motor 1 is positioned and continues to rotate at a low speed while maintaining a constant opening, the pressure in the discharge line 44 of the drive motor 1 is naturally lower than in the supply line 43, and therefore The drain port 60 has this discharge side line 44.
pressure is applied. This discharge side line 44 communicates with the tank via lines 40, 46, and 32, and a variable orifice 49 is interposed in these lines, so at least this variable orifice 49 The pressure in the discharge side line 44, that is, the drain port 60, becomes higher than the tank pressure by the amount of pressure loss during circulation. Then, especially near the index position, the roller 2
0 rolls along the substantially tapered portion 16 of the cam 12, that is, in the process in which the flow rate directional control valve 14 gradually reduces the opening degree at the symbol position S3, the discharge side line 44, that is, the drain port At 60, the pressure is higher than the tank pressure. That is, at this time, the indexed object 4 is decelerated, and the inertial force of the indexed object 4 and the like acts to increase the pressure in the discharge side line 44. That is, the inertial force acts to maintain a constant discharge amount from the drive motor 1, while the flow path on the discharge side is gradually narrowed by the variable orifice 49. As a result, pressure increases in the discharge line 44. Such an increase in pressure on the discharge side may exceed the pressure on the supply side if the moment of inertia of the indexed object 4 is large. At this time, the pressure of the drain port 60 is the same as that of the supply line 43. In either case, a high pressure that is significantly different from the tank pressure acts on the drain port 60 of the drive motor 1, and as a result, the pressure between the working fluid pressure flowing inside the drive motor 1 and the drain port 60 is The difference is much smaller than in conventional equipment where the drain port is directly connected to the tank. Therefore, the amount of drain inside the drive motor 1 that depends on the pressure difference becomes smaller, and therefore most of the working fluid supplied to the drive motor 1 contributes to the driving force of the drive motor 1. In conventional devices, a large pressure difference occurs between the working fluid pressure flowing inside the drive motor and the drain port directly connected to the tank, and the amount of drain generated due to this pressure difference reduces the supply flow rate to the drive motor. However, in the above device, as the amount of drain is reduced as described above, the controllability when supplying a minute flow rate is improved. Therefore, in the deceleration process when the indexed body 4 comes to a stop, controllability of smoothly decelerating to a lower speed side is maintained, and therefore, it is possible to provide a stopping operation without impact.

As described above, in the above embodiment, the amount of drain in the drive motor 1 is significantly reduced, especially during deceleration, and as a result, controllability when supplying a minute flow rate is improved, and smooth deceleration control is possible. Furthermore, it is possible to perform a stopping operation without impact.

Although one embodiment of the present invention has been described above, the position indexing device of the present invention is not limited to the above embodiment, and can be implemented with various modifications. For example, in the embodiment described above, the circuit is configured to have a switching function between normal rotation and reverse rotation of the drive motor 1, and for this reason, check valves 6 are provided in the lines 43 and 44 on the supply side and the discharge side to the drive motor 1, respectively.
Although the drain port 60 is connected to the lines 61 and 62 with the lines 61 and 62 interposed between the lines 61 and 64, when the drive motor is used to rotate only in one direction, the drain port is connected only to the discharge side line. year,
Further, the check valve can also be omitted. Further, in the above embodiment, a line 46 that bypasses the flow direction control valve 14 is provided, and a throttle 45 is interposed in this line, and this throttle 45 and the flow direction control valve 14 are connected to each other.
The variable orifice 49 is configured with the variable orifice 48 in
It is also possible to have a configuration in which 5 is omitted. Furthermore, in the above description, an example has been described in which the flow rate directional control valve 14 is used to simultaneously control the supply side flow rate as well as the discharge side flow rate of the drive motor 1. It is also possible to have a configuration in which the Further, in the above description, the drive motor 1 is configured with a dual-shaft drive motor, but in addition, for example, a drive motor having one main shaft is used, and the object to be indexed is driven by this main shaft.
It is also possible to have a configuration in which the cam is attached to the main shaft directly or via another member.

(Effects of the Invention) As described above, in the position indexing device of the present invention, the amount of drain in the drive motor is reduced, especially during deceleration operation, and therefore the ratio of the amount of drain to the flow rate supplied to the drive motor is reduced. Therefore, the controllability is improved even when a minute flow rate is supplied, and as a result, it becomes possible to obtain smoother deceleration control and a stopping operation with reduced impact.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a position indexing device according to an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the above device, Fig. 3 is a cross-sectional view taken along the line of Fig. 2, and Fig. 4. is a circuit diagram of a conventional device. 1... Drive motor, 4... Indexed object, 49...
Variable orifice, 60...Drain port.

Claims (1)

[Claims] 1 A variable orifice 49 is interposed in the lines 44, 40, 46, and 32 that connect the drive motor 1 that drives the indexed object 4 to the tank, and the variable orifice 49 is set to a small opening state near the indexing position. 1. A position indexing device configured to decelerate as described above, characterized in that a drain port 60 of the drive motor 1 is connected to a line 44 in front of the variable orifice 49.