JPH0453881Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is applicable to workpiece clamping devices, such as
Regarding the improvement of a clamping device used when performing cutting processing such as boring and drilling on an automobile differential gear case as a workpiece, in particular, reducing the number of actuators and the number of operation detection means. This simplifies the structure of the device and advantageously shortens the time required for clamping and unclamping the workpiece.

(Conventional technology) This type of conventional work clamp device includes:
An example is shown in FIG.

Here, a plurality of workpiece positioning claws 1 are attached to the main body part 2 at predetermined angular intervals in the circumferential direction with respect to the workpiece w to be clamped, and each of these workpiece positioning claws 1 is moved forward and backward in the radial direction of the workpiece w. By making it driveable, each workpiece positioning claw 1 can be positioned in front of various workpieces w.
Ensure access to w _f .

Moreover, here, on the back side of the workpiece w to be clamped, a plurality of cylinders 3 are attached to the main body part 2 at predetermined intervals in the circumferential direction of the workpiece w.
are mounted parallel to each other, and a clamp rod 4 is connected to the piston rod 3a of each cylinder 3. Each of these clamp rods 4 has a clamp pin 4a at its tip, and when the piston rod 3a moves forward, this clamp pin 4a comes into contact with the back surface w _r of the workpiece w and moves the workpiece w into a workpiece positioning claw. Press in direction 1.

Here, each double-acting cylinder 3 is connected to a pump 8 and a reservoir tank 9 via a switching valve 7 connected to fluid passages 5 and 6 that control supply and discharge of working fluid thereto, and Moreover, pressure switches 10 and 11 are attached to each of the fluid passages 5 and 6, respectively, for generating an electric signal when the internal pressure of each passage becomes equal to or higher than a predetermined value.

Further, in this case, each lock rod 12 is arranged parallel to each clamp rod 4 and movable in the axial direction thereof, and one end of each lock rod 12 is attached to the base frame 2 as described above. Piston rod 13 of another cylinder 13 pointing in the opposite direction to cylinder 3
Connect to a. Therefore, the lock rod 12 is moved back and forth in the direction opposite to that of the clamp rod 4 by the movement of the piston rod 13a.

Respective fluid passages 14 and 15 connected to the cylinder 13 for causing such forward and backward movement of the lock rod 12 are connected to a pump 8 through a switching valve 16.
and reservoir tank 9, and pressure switches 17, 18 similar to those described above are attached to their respective passages 14, 15, respectively. Here, a pressure reducing valve 19 is connected to the passage 14 in order to prevent the lock pin, which will be described later, from getting caught between the lock rod 12 and the clamp rod 4. We are trying to reduce this.

Furthermore, in this example, a cam surface 20 consisting of an inclined surface is provided at the rear end portion of the lock rod 12, and a lock pin 21 is provided on the main body portion 2, which contacts the cam surface 20 at a portion of the lock rod 12 near its retraction limit position. , is attached so that it can move forward and backward with respect to the clamp rod 4. Here, the cam surface 20 is inclined in a direction that gradually reduces the axial cross-sectional height of the lock rod 12 toward the rear edge,
The lock pin 21 that makes surface contact with this cam surface 20 is
Based on the backward movement of the lock rod 12, it is advanced toward the clamp rod side.

On the other hand, the clamp rod 4, which is brought into contact with the locking pin 21 by such advancing movement, is provided with an inclined surface 22 in its intermediate portion, which is substantially parallel to the cam surface 20, so that the inclined surface 22 When the lock pin 21 comes into contact with the clamp rod 4, a clamping force increasing force is applied to the clamp rod 4, in addition to a rod restraining force directed in a direction perpendicular to the axis of the rod, as well as a clamping force increasing force directed in the advancing direction of the rod.

In addition, in the place shown in this figure, 23, 24
2 shows a lock pin support member which also serves as a rotation stopper for the lock pin 21, respectively.

Clamping of a workpiece in the conventional apparatus configured as described above is performed as follows.

Initially, each workpiece positioning claw 1 is placed on the workpiece w temporarily placed on a mounting jig (not shown).
1 by displacing the claws toward each other in the radial direction.
is brought into contact with or able to come into contact with the front surface w _f of the workpiece w, as shown in the figure, the front surface of the large diameter portion, and then the piston rod 3a of each cylinder 3 is advanced by the respective switching valve 7.

This advancement of the piston rod 3a causes the forward movement of the clamp rod 4 and therefore the movement of the clamp pin 4a.
This brings the workpiece into contact with the workpiece rear surface w _r , whereby each clamp rod 4 presses the workpiece w against the workpiece positioning pawl 1 based on the cylinder internal pressure.

After temporarily clamping the workpiece w in this way, the pressure switch 1 is activated to detect the end of the temporary clamping.
operate the switching valve 16 based on the signal from 0,
Pressure reducing valve 1 into the rod side fluid chamber of cylinder 13
Supply low pressure fluid through 9. Due to this,
Both the piston rod 13a and the lock rod 12 connected thereto are moved backwards with a small force, with the result that the lock pin 21 abuts against the inclined surface 22 of the clamp rod 4, also with a small force. That will happen.

Therefore, in this case, not only is the lock pin 21 sufficiently prevented from being caught, but also the lock pin 21 is firmly attached to the inclined surface 22 and eventually to the clamp rod 4.
The above-mentioned rod restraining force and clamping force increasing force are respectively applied to the rod, thereby completing complete clamping of the workpiece w.

Here, the end of such operation of the lock pin 21 is detected from the signal from the pressure switch 17.

After completing the clamping of the workpiece w as described above, the lock pin 2
The workpiece w can be reliably supported under the action of.

After finishing the cutting process on the workpiece w, first, the switching valve 16 is operated to advance the lock rod 12 to its forward limit position with the original pressure, thereby rendering the lock pin 21 inactive. After detection by the switch 18, the clamp rods 4 are operated backward by the switching valve 7, and after the pressure switch 11 detects that each clamp rod 4 has reached the backward limit position, the workpiece w is taken out. This completes one cycle of the workpiece clamping device.

(Problems to be Solved by the Invention) However, in such a conventional device, each clamp rod 4 is driven by each independent cylinder 3, so the structure of the device becomes complicated. There is a problem that equipment costs increase, and since this device waits for the completion of one of the two types of cylinders 3 and 13 before operating the other, the time required to clamp and unclamp the work w is shortened. I had a problem with it being long.

This invention advantageously solves the problems of the prior art, and provides a workpiece clamping device that effectively reduces equipment costs and running costs, as well as significantly shortens operating time.

(Means for Solving the Problems) This invention has a workpiece positioning claw, clamp rod, and lock pin similar to those described in the conventional example, as well as a main shaft and a cam surface corresponding to the lock rod and cam surface of the conventional example. In a work clamping device which further includes a cylinder and a switching valve for driving the main shaft, one end of a connecting plate connecting the main shaft with a clamp rod is fixed to the main shaft, and the other end of the connecting plate is fixed to the main shaft. the end portion is attached to the clamp rod via an elastic means that biases the clamp rod in its advancing direction;
The piston of the driving cylinder of the main shaft is attached to the piston rod so as to be relatively movable over a predetermined amount in the axial direction of the piston rod.

(Function) Clamping of a workpiece by this device is performed by retracting the piston rod of the cylinder and eventually the main shaft based on the operation of the switching valve. The plate biases the clamp rod in the advancing direction via elastic means. Therefore, the clamp rod is moved to the extension limit position, where it touches the back of the workpiece.
It is pressed by the restoring reaction force of the elastic means. The subsequent backward movement of the main shaft then causes the lock pin to be displaced forward by the cam surface provided thereon, causing the lock pin to abut, or in other words lock, against the clamp rod.

On the other hand, unclamping the workpiece is
The switching action of the switching valve brings about the forward movement of the piston rod, which is effected first by releasing the locking pin and then by causing the retraction movement of the clamp rod.

Therefore, here, there is no need for cylinders for operating the clamp rods, piping for those cylinders, etc., and the structure of the device is significantly simplified, making it possible to sufficiently reduce equipment costs and running costs. .

Moreover, with this device, the workpiece can be clamped and unclamped by operating one type of cylinder, so the time spent on these operations can be effectively reduced.

Furthermore, according to this device, when unclamping a workpiece, the piston is operated idly against the piston rod over a predetermined length and then collided with the piston rod, thereby causing the piston to move against the cam surface provided on the main shaft. It is possible to sufficiently prevent the lock pin from biting into the lock pin without providing a pressure reducing valve as described in the prior art, and at the same time,
The driving cylinder can be moved more quickly in the direction of the work ramp.

(Example) This invention will be explained below based on illustrated examples.

FIG. 1 is a partially sectional side view showing an embodiment of this invention, and in the figure, parts similar to those described in the conventional example are designated by the same numbers.

That is, in the figure, 1 indicates a workpiece positioning claw, and 2 indicates a main body portion, and here, a plurality of workpiece positioning claws are attached to the main body portion 2 at predetermined angular intervals in the circumferential direction of the workpiece w to be clamped. Each of the claws 1 can be driven forward and backward in the radial direction of the workpiece w to contact the front surface w _r of the workpiece w.

Further, reference numeral 4 indicates respective clamp rods arranged at predetermined intervals in the circumferential direction on the back side of the work w to be clamped. They are supported so that they can move forward and backward in directions and are parallel to each other.

Here, each main shaft 31 that is parallel to each clamp rod 4 is disposed within the main body portion 2 so as to be movable in the axial direction thereof, and the rear end of each of these main shafts 31 is
It is connected to a piston rod 32a of a cylinder 32 arranged in the same manner as the cylinder 13 of the conventional device.
Here, a piston 32b is mounted on the small-diameter rear end of the piston rod 32a so as to be relatively displaceable over a predetermined amount in the axial direction thereof, and a fluid passage that controls supply and discharge of working fluid to and from the cylinder 32 is provided. 14 and 15 are connected to a pump 8 and a reservoir tank 9, respectively, via a switching valve 16.
Note that 17 and 18 in the figure are fluid passages 14 and 18, respectively.
15 shows a pressure switch similar to the conventional example.

Here, a cam surface 33 similar to that described in the conventional example is provided at the rear end portion of the main shaft 31.
The cam surface 33 allows the lock pin 21 disposed on the main body portion 2 to move forward and backward relative to the clamp rod 4. Here, the cam surface 33 is inclined at an angle of 5° with respect to the axis, for example, in a direction that gradually reduces the cross-sectional height of the main shaft 31 in the axial direction toward the rear edge. 21 is in surface contact with the cam surface 33.

The inclined surface 22 of the clamp rod 4, which together with the cam surface 33 and the lock pin 21 constitute the locking mechanism, also has a direction in which its axial cross-sectional height gradually decreases toward its rear end. , for example, at an angle of 9° to the axis. For this reason, here, when the main shaft 31 moves backward, the lock pin 21, which is displaced forward toward the clamp rod by its cam surface 33, is brought into contact with the inclined surface 22 of the clamp rod 4, so that the clamp rod 4 is In addition to a large rod restraining force directed in the direction orthogonal to the rod axis, a clamping force increasing force directed in the advancing direction is effectively applied, so that the clamp rod 4 can clamp the workpiece w with sufficient certainty. It will be held on.

In addition to these, one end of the connection plate 34 is bolted to the tip of the main shaft 2 protruding from the main body portion 2 in a direction perpendicular to the axial direction of the connection plate 34. Clamp rod 4 at the other end of plate 34
It is connected to the rear end of the body via a coil spring 35 as an elastic means. This connection of the connecting plate 34 to the clamp rod 4 involves a connecting pin 36 with a stopper at its rear end.
4 and is screwed and fixed to the clamp rod 4 so that the connecting plate 34 can be displaced relative to the pin 36 in the advancing direction, and around the connecting pin 36, between the connecting plate 34 and the clamp rod 4 This is done by interposing a coil spring 35 that generates a work clamping force of the clamp rod 4.

Therefore, here, when the connecting plate 34 is operated in the advancing direction of the clamp rod 4 by the backward operation of the main shaft 31, the clamp rod 4 is moved forward via the coil spring 35, and After the clamp pin 4a at the tip of the clamp rod comes into contact with the back surface _wr of the workpiece w, the deformation of the coil spring 35 based on the continuous operation of the connecting plate 34 causes the clamp rod 4 to react to the deformation reaction force of the coil spring 35. A corresponding workpiece clamping force will be applied.

Note that 37 in the figure indicates a rotation stop pin of the main shaft 31.

To clamp a workpiece using such a workpiece clamping device, first, each workpiece positioning claw 1 is moved radially inward toward the workpiece w temporarily placed on a mounting jig (not shown), and each of these positioning claws is 1 is brought into contact with or can be contacted with the front surface w _f of the workpiece w, in the illustrated example, the front surface of the large diameter portion, and then the switching valve 16 is operated to bring about the backward movement of the piston rod 32a and eventually the main shaft 31. .

Here, when the main shaft 31 moves backward, the piston 32b is first moved backward relative to the piston rod 32a, and after this backward displacement is completed, the main shaft 31 moves along with the piston rod 32a as shown by the imaginary line in the figure. You will begin to gradually retreat from your position. At the beginning of the backward displacement, the main shaft 31 is moved by the coil spring 3 by the connecting plate 34.
5 causes forward displacement of the clamp rod 4.

By the way, after the clamp pin 4a at the tip of the clamp rod 4 comes into contact with the back surface _w of the workpiece w, the clamp rod 4 can no longer move forward, so the main shaft 31 is no longer able to move forward due to the coil spring caused by the connection plate 34. A compressive deformation of 35 is applied to the clamp rod 4.
For example, it provides a workpiece clamping force of about 15 kg.

After the temporary clamping of the workpiece has been completed in this way, the main shaft 31 causes a forward displacement of the lock pin 21 by the cam surface 33 provided thereon by its continued backward movement, and the lock pin 21 is moved to the clamp rod 4. the inclined surface 22 of. As a result, the locking pin 21 applies the aforementioned rod restraining force and clamping force increasing force to the clamp rod 4, thereby locking the clamp rod 4 in the workpiece clamping position.

Then, when the lock is completed, press the pressure switch 1.
After the detection at step 7, cutting of the workpiece w is started.

On the other hand, unclamping the workpiece is
Based on the operation of the switching valve 16, first, the piston 32b existing in the illustrated position is moved to the piston rod 3.
Based on the stroke on the small diameter rear end of the clamp rod 2a, the large diameter end of the clamp rod 2a collides with the large diameter end to release the lock between the cam surface 33 and the lock pin 21, and then the clamp rod 4 is moved to the backward limit position by the connecting plate 34. This causes the pressure switch 18 to return.
The workpiece w, which has been unclamped in this way, is removed from the apparatus by the subsequent release of the workpiece positioning claw 1.

Therefore, here, the clamping operation of the work w and the locking operation of the clamp rod 4 can be effected continuously by operating only the cylinder 32 for driving the main shaft. Compared to conventional technology, equipment costs, running costs and operating time can be significantly reduced.

Furthermore, when unclamping the workpiece, the lock pin 21 is sufficiently prevented from biting against the cam surface 33 by the hammering action produced by colliding the piston 32b with the large diameter end of the piston rod 32a. Therefore, it is not necessary to specially provide a pressure reducing valve for this purpose, and the delay in work clamping operation caused by providing a pressure reducing valve can be completely eliminated.

(Effects of the invention) As is clear from the above, this invention eliminates the need for the actuator for driving the clamp rod, as well as the switching valve, piping, wiring, etc. associated with the actuator. As a result, equipment costs and running costs can be significantly reduced.Moreover, a single type of actuator is used to continuously perform the clamping action of the clamp rod and the locking of the clamp rod. The time required for clamping and the time required for unclamping can be significantly reduced.

Furthermore, when unclamping the workpiece, by causing the piston to collide with the piston rod, it is possible to prevent the lock pin from biting into the main shaft cam surface. This eliminates the need to attach the workpiece clamp, and it is possible to avoid delays in work clamp operation caused by the attachment.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing an embodiment of this invention, and FIG. 2 is a side view similar to FIG. 1 showing a conventional example. w...Work, w _f ...Front, w _r ...Back, 1
...Work positioning claw, 2...Main body part, 4...
Clamp rod, 8... Pump, 9... Reservoir tank, 14, 15... Fluid passage, 16... Switching valve, 21... Lock pin, 22... Inclined surface, 31
...Main shaft, 32...Cylinder, 33
...Cam surface, 34...Connecting plate, 35...Coil spring, 36...Connecting pin.

Claims (1)

[Claims for Utility Model Registration] A plurality of workpiece positioning claws 1 arranged at intervals in the circumferential direction of the workpiece W and contacting the front surface W _f of the workpiece; A plurality of mutually parallel clamp rods 4 that move forward and backward with respect to the back surface W _r of the workpiece, which is arranged and whose position is specified by a workpiece positioning claw; main shaft 31, and a driving cylinder 32 connected to one end of each main shaft.
, a switching valve 16 that controls the supply and discharge of fluid to each cylinder, and a lock pin 21 that is moved forward and backward relative to the clamp rod by a cam surface 33 provided on the main shaft and locks the clamp rod in a predetermined extended position. In the work clamping device, one end of a connecting plate 34 that connects the main shaft 31 with the clamp rod 4 is fixed to the main shaft 31, and the other end of the connecting plate is used to urge the clamp rod in its advancing direction. The piston 32b of the driving cylinder 32 is attached to the clamp rod via an elastic means 35.
is attached to a piston rod 32a so as to be relatively movable over a predetermined amount in the axial direction of the piston rod 32a.