JPH0445289B2 - - 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 FIG. 5 shows the configuration of the device. In the figure, reference numeral 81 denotes a hydraulic drive motor, and the drive motor 81 rotates an object to be indexed, such as a rotary table. 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 and a flow direction control valve 85. 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.
This contactor 87 is configured 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, at the position where the contact 87 is fitted into this recess 89, the The spool 86 is located at the most extreme position (right end position in the figure), and at this time, the flow direction control valve 85 is located at the symbol position S1, and the drive motor 81
No fluid is supplied to the indexed position, and the indexed position is stopped.

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 90, 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, 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 connected to this fluid pressure and the spring force. The contact 87 is pushed toward the cam 88 at the tip.
This force also presses and contacts the cam surface. That is, the spool 86 responds to the cam surface of the cam 88. In this state, the flow rate directional control valve 85 is located at the symbol position S3, and the opening degree is slightly reduced while maintaining the communication state, and the drive motor 81 is in a state where the speed is slightly reduced from the above. to continue rotating. When the contact 87 of the spool 86 again reaches the position of the recess 89 and is fitted into the recess 89, the flow direction control valve 85 returns to the symbol position S1,
The supply of pressure fluid to the drive motor 81 is stopped, and the drive motor 81 stops at this indexed position, completing 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.

(Problem to be solved by the invention) By the way, when the above-mentioned position indexing device is used in an automatic tool changer of a machining center, it is necessary to use a high-speed It is required to have the characteristic that it can be driven at However, when the position indexing device having the above structure is driven at high speed, the shock when the position index stops becomes excessive, causing a problem that the cam 88 and the roller 87 are damaged. This is because the torque required for deceleration increases in proportion to the rotational speed of the drive motor 81. In order to solve this problem, it is conceivable to increase the deceleration time and reduce the deceleration torque, but since this deceleration time is determined by the shape of the cam 88, Even if you try to increase the deceleration time, a limit will naturally arise. In other words, the dimensions of the cam 88 are limited in order to make the device more compact, and the number of indexing positions (that is, the number of recesses 89) per rotation of the cam 88 is required to be multiple. This is because it cannot be set, and this is a major reason why the position indexing device cannot be driven at high speed.

The present invention was made to solve the above-mentioned conventional drawbacks, and its purpose is to provide a position indexing device that enables high-speed driving and has improved deceleration characteristics.

(Means for solving the problem) Therefore, in the position indexing device of the present invention, the first supply line 31 that supplies fluid to the drive motor 1
Alternatively, a flow control valve 14 is interposed in the line 32 that discharges fluid from the drive motor 1 to the tank, and the flow control valve 14 is provided with a spool 22 that opens and closes the variable throttle 47, and a cam interlocked with the drive motor 1 is provided. 1
By bringing the contactor 20 that interlocks with the spool 22 into contact with the cam surface of 2, the spool 22
is made to respond to the cam shape, and a reduction part 1 is installed on the cam surface.
6 and a stop part 17, and when the contactor 20 contacts the deceleration part 16, the variable aperture 47
The contactor 20 further reduces the opening degree of the stop part 1.
The variable throttle 47 is configured to be closed when the contactor 7 comes into contact with the cam surface, and a moving means 70 is provided for bringing the contactor 20 into contact with and away from the cam surface, while supplying fluid to the drive motor 1. Further, the other second supply line 66 is provided, and an opening/closing means 63 is interposed in this supply line 66, and the moving means 70 and the opening/closing means 63 are interlocked, so that the moving means 70 operates the contactor 20. The opening/closing means 63 is operated to open while the contactor 20 is being moved in a direction away from the cam surface, and the moving means 70 is configured to bring the contact 20 into contact with the cam surface after the opening/closing means 63 is closed. It has been done.

(Function) In the above position indexing device, when starting to drive the drive motor 1, the moving means 70 moves the contact 2
0 in the direction away from the cam surface, and the opening/closing means 63 is operated to open. Then, fluid is supplied to the drive motor 1 from both the first supply line 31 and the second supply line 66, and the opening degree of the variable throttle 47 is large.
The amount of fluid supplied to the drive motor 1 becomes large, so that the drive motor 1 is driven at high speed. On the other hand, when stopping the drive motor 1, first the opening/closing means 63 is operated to close. Then, the fluid supply from the second supply line 66 is stopped, the amount of fluid supplied to the drive motor 1 is reduced, and the first stage of deceleration is performed. Next, the contactor 20 is moved by the moving means 70 and brought into contact with the cam surface. Then, cam 1 linked to drive motor 1
2, the contactor 20 comes into contact with the speed reducer 16 provided on the cam surface, and the spool 22 moves to reduce the opening degree of the variable throttle 47, thereby reducing the amount of fluid supplied to the drive motor 1. The second stage of deceleration is performed by decreasing When the contactor 20 comes into contact with the stop part 17 due to the movement of the cam 12 in this decelerated state, the variable throttle 47 is closed, the drive motor 1 is stopped, and the position indexing operation is started. finish.

(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 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
5, a tapered portion 16 gradually moves toward the center thereof.
and a recessed portion 17 located at the center of the tapered portion 16 at 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 roller 20 as a contactor is rotatably supported. The tapered portion 16 provided on the cam 12 is a deceleration portion, and the recess 17 is a stop portion, and the recess 17 has a shape into which the roller 20 can fit. Further, the tip of the arm 21 of the lever 13 that extends upward in the figure is pivotally connected via a pin 24 to a rod 23 that is integrally formed on the proximal end side of the spool 22 of the flow direction control valve 14. ing.

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 first supply line 31 branched from a discharge line 30 connected to a hydraulic pump (not shown), and a tank port T connected to a tank line 32. It has three ports A, B, and M on the side. 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). Further, on the opposite side of this spring chamber 34, there is a pilot chamber 3.
5 is provided, and when fluid is introduced into this pilot chamber 35, the fluid pressure in this 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, the communication state shown in the symbol positions S2 and S3 is given. First, when the spool 22 is in the most retracted state, it is located at the symbol position S2, the pump port P is connected to the port B, and the tank port T is connected to the symbol position S2. It 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,
At this position, the communication state at the symbol position S2 is maintained, and the flow path is gradually narrowed as the spool 22 moves toward the tip side.

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 a first electromagnetic switching valve 38 for switching between forward and reverse rotation of the drive motor 1 through lines 39 and 40, respectively. Also, the above line 3 connected to the above port B
A branch line 41 branched from 9 is connected to an upward pressure supply port 42 of the hydraulic cylinder 10. The secondary port of the first 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, for example, the indexed object 4 is changed and the rotational load is changed, 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 4 is connected in parallel to the variable throttle 48 of the flow direction control valve 14.
5 is provided, and by adjusting this throttle 45, deceleration corresponding to the rotational load of the indexed object 4 can be easily applied.

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, the second electromagnetic switching valve 5
1, and the primary side ports P and T of this switching valve 51 are connected to branch lines 52, which are branched from the first supply line 31 and the tank line 32, respectively.
53, one secondary port B is blocked, and the other secondary port is connected to the spring chamber 34 of the flow rate directional control valve 14 via a pilot line 55. Note that the flow rate directional control valve 1
The pilot chamber 35 of No. 4 is connected to the pilot line 54.
It is connected to the first supply line 31 via.

In the above device, a branch line 60 branched from the discharge line 30 and a tank 61 are further provided.
The tank line 62 that communicates with
It is connected to the. Further, branch lines 64 and 65 branched from the pair of lines 43 and 44 connected to the drive motor 1 are connected to the secondary ports A and B of the third electromagnetic switching valve 63, respectively. Note that 67 is a pressure reducing valve, and the branch line 6
This is for setting a fluid pressure of 0.

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 second electromagnetic switching valve 51 is located at the symbol position S2 in FIG. It is assumed that the electromagnetic switching valve 38 and the third electromagnetic switching valve 63 are also located at the neutral position. In this state, spring 3
3 and the force caused by the fluid pressure in the spring chamber 34 are larger than the force on the pilot chamber 35 side, so the spool 22 is pressed toward the tip side. 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. Also, at this time, the flow rate directional control valve 14 is located at the symbol position S1, so the fluid in the first supply line 31 is transmitted from port A to the descending side pressure port 36 of the hydraulic cylinder 10 via the line 37, and The rising side pressure supply port 42 is open to the tank line 32 through the line 41, and the indexed body 4 is pushed down and the coupling teeth provided on the indexed body 4 side and the base side are engaged with each other, and the indexed body 4 is opened to the tank line 32 through the line 41. It is mechanically fixed in the extended position. 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 second electromagnetic 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 spring chamber 34 is opened to the tank line 32 via the pilot line 55. On the other hand, since the fluid pressure of the first supply line 31 is acting on the pilot chamber 35 via the pilot line 54, the spool 22 is moved by the spring force of the spring chamber 34 due to the high pressure fluid in the pilot chamber 35. It resists and moves toward the tip side. Along with this switching movement, lever 1
3 rotates, and the roller 20 is removed from the recess 17. Further, 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 first supply line 31 is communicated with the port B via the pump port P, and at this time, the hydraulic pressure is increased. The ascending pressure supply port 42 of the cylinder 10 is supplied with the fluid of the first supply line 31 via the line 41, and the descending pressure supply port 36 is opened to the tank line 32 via the line 37. The projector 4 is raised, and the coupling teeth are disengaged, making it possible to rotate. Then, the first electromagnetic switching valve 38 is set, for example, to the forward rotation position in response to an unclamping completion signal transmitted upon completion of the upward movement of the indexed object 4, and the pressure fluid from the first supply line 31 is transferred to the lines 39, 43. The discharge side lines 44 and 40 communicate with the tank line 32 via the port M. Also, almost at the same time, the third
The solenoid switching valve 63 is in the forward rotation position (symbol position S1)
Switch to Then, the fluid in the discharge line 30 is transmitted to the drive motor 1 via the second supply line 66 constituted by the branch line 60 and the line 64, and the discharge side line 65 is connected to the tank line 62. communicate with. That is, the fluid in the discharge line 30 is supplied to the drive motor 1 from both the first supply line 31 and the second supply line 66, and on the discharge side, the fluid is supplied to the tank from both the line 40 and the line 65. As a result, the drive motor 1 is driven at a higher speed than before, and the indexed object 4 is operated at high speed (FIGS. 4A and 4B).

When it is detected by the passage of time or the rotational speed of the drive motor 1 that the indexed object 4 has reached the vicinity of the indexed position, the third electromagnetic switching valve 63 is returned to the neutral position S0. Then, in the third electromagnetic switching valve 63, all the ports P, T, A, and B on the primary and secondary sides will be blocked, so the fluid to the drive motor 1 via the lines 64 and 65 will be blocked. supply and discharge will be stopped. In other words, fluid is supplied and discharged to and from the drive motor 1 only through the lines 39 and 40, and as a result of this reduction in the amount of fluid supplied and discharged to the drive motor 1, the rotational speed of the drive motor 1 is reduced. A first stage of deceleration is performed in which the rotational speed is reduced to a speed commensurate with the amount of supply and discharge (FIG. 4C).

On the other hand, during the first stage of deceleration as described above, the second electromagnetic switching valve 51 is returned to the symbol position C2 again. In this way, the switching valve 5
1 at the symbol position C2, the spring chamber 3
4, the fluid from the first supply line 31 is guided again, so the spool 22 is moved toward the tip side by the fluid pressure and spring force in the spring chamber 34, and the lever 1
3 is rotated, and the roller 20 contacts the arcuate portion 15 of the cam 12 and rolls.

As the drive motor 1 continues to rotate,
The tapered portion 16 of the cam 12 allows variable apertures 47, 4
The opening degree of 8 is gradually reduced, the flow path is gradually narrowed, and the drive motor 1 is decelerated in the second stage (FIG. 4D). After that, the cam 1 is placed at the position of the roller 20.
When the recess 17 of 2 is positioned, the roller 2
0 fits into the recess 17, and the flow direction control valve 14 is located at the neutral position S1 again. At this time, the fluid pressure supply state to the hydraulic cylinder 10 is reversed, the indexed body 4 is pushed down, and the indexed body 4 side and the base 7 are
Coupling teeth provided on both sides are engaged with each other to fix the indexed body 4 at the indexed position. At the same time, as above, the line 3 leading to the drive motor 1
9 and 40 are both opened to the tank line 32, the driving of the drive motor 1 is stopped and indexing is completed.

As described above, in the position indexing device, when the drive motor 1 drives the indexed object 4, the fluid in the discharge line 30 is supplied to the drive motor from the second supply line 66 in addition to the first supply line 31. 1
Therefore, it is possible to drive the indexed object 4 at a higher speed than conventionally. Also,
The first stage of deceleration is performed by stopping the fluid supply from the second supply line 66, and then the second stage of deceleration is performed by controlling the opening degree of the variable throttle 47 according to the cam shape. Therefore, a smooth deceleration characteristic can be obtained, and therefore, a shock-free indexing and stopping operation can be performed even while performing high-speed driving. Therefore, for example, in an automatic tool changer, tools can be taken out at high speed and smoothly without any shock, thereby making it possible to improve the main function.

Although one embodiment of the present invention has been described above,
The position indexing device of the present invention is not limited to the embodiments described above, and can be implemented with various modifications. For example, in the above embodiment, the moving means 70 for moving the roller 20 toward and away from the cam surface is moved by the spring 3.
3. Spring chamber 34, pilot chamber 35, pilot lines 54, 55, branch lines 52, 53, second
Although the electromagnetic switching valve 51 and the like are used, other configurations may be adopted. 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 adopt a configuration in which the filter is interposed. 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, when the drive motor drives the indexed object, the drive motor is also supplied from the additionally provided second supply line. Therefore, it becomes possible to drive the indexed object at a higher speed than before. Also, the second
The first stage of deceleration is performed by stopping the fluid supply from the supply line, and then the second stage of deceleration is performed by controlling the opening of the variable throttle according to the cam shape, resulting in smooth operation. A deceleration characteristic is obtained, and therefore a shock-free indexing and stopping operation can be performed even while performing high-speed driving. Therefore, for example, in an automatic tool changer, tools can be taken out at high speed and smoothly without any shock, thereby making it possible to improve the main function.

[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 graph showing the operating state in comparison with the conventional device, and FIG. 5 is a circuit diagram of the conventional device. DESCRIPTION OF SYMBOLS 1... Drive motor, 12... Cam, 14... Flow rate (direction) control valve, 16... Taper part (reduction part),
17... Recess (stop part), 20... Roller (contact), 31... First supply line, 32... Tank line, 47... Variable throttle, 63... Third electromagnetic switching valve (opening/closing means) , 66...second supply line, 7
0... Means of transportation.

Claims (1)

[Claims] 1. A flow rate control valve 14 is interposed in the first supply line 31 that supplies fluid to the drive motor 1 or the line 32 that discharges fluid from the drive motor 1 to a tank, and the flow rate control valve 14 has a variable throttle 47 configured to open and close. The spool 22 is provided with a spool 22, and the spool 22 is made to respond to the cam shape by contacting the cam surface of the cam 12 that is interlocked with the drive motor 1 and the contact 20 that is interlocked with the spool 22. A portion 16 and a stop portion 17 are provided, and the contactor 20
When the contactor 20 contacts the deceleration part 16, the opening degree of the variable throttle 47 is reduced, and when the contactor 20 contacts the stopper part 17, the variable throttle 47 is closed.
Moving means 7 for bringing 0 into contact with and away from the cam surface
0, and yet another second supply line 66 for supplying fluid to the drive motor 1.
, an opening/closing means 63 is interposed in the supply line 66, and the moving means 70 and the opening/closing means 63 are connected to each other.
When the moving means 70 is moving the contactor 20 in the direction away from the cam surface, the opening/closing means 63 is opened, and after the opening/closing means 63 is closed, the moving means 70 is opened. A position indexing device configured to bring the contact 20 into contact with the cam surface.