JPH03281135A - Clamp rod direct acting type hydraulic clamp - Google Patents

Abstract

PURPOSE:To prevent slipping displacement of a fixed object due to external force at the time of unclamping by reciprocatively connecting a piston to the other end side part of a clamp rod, and providing a pre-load spring for pressing the clamp rod to the other end side. CONSTITUTION:A piston 10 is connected for freely controlled reciprocating to the other end side part of a clamp rod 16 via a clamp stroke control means 21, and a pre-load spring 23 is interposed on the way from a cylinder body 7 through the piston 10 and the clamp stroke control means 21 to the other end side part of the clamp rod 16. The pre-load spring 23 is installed so as to press the clamp rod 16 to the other end side relative to the cylinder body 7. Discharge of pressure oil from a clamp hydraulic oil chamber 9 at the time of unclamping retracts the piston 10 in relation to the cylinder body 10. The pre-load spring 23, however, prevents more retraction than a predetermined amount and simultaneously the pressing force thereof fixes a fixed object B with slight friction to a fixing table A via the cylinder body 7.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a hydraulic clamp that presses and fixes an object to be fixed, such as a workpiece chuck unit or workpiece, to a fixing base of a machine tool, etc. using a hydraulic cylinder. The present invention relates to a clamp rod direct-acting hydraulic clamp in which an object to be fixed is clamped and fixed between a fixing base and a cylinder body via the clamp rod by linearly driving the clamp rod via a piston with hydraulic pressure.

(Basic Structure as Prerequisite) Some of the clamp rod direct-acting hydraulic clamps to which the present invention is directed have the following basic structure.

For example, from Figure 1 to Figure 3, or Figure 4, Figure 5,
As shown in FIG. 6 or FIG. 7, a clamp hydraulic oil chamber 9 and a piston 10 are provided in order from one end of the cylinder body 7 of the hydraulic cylinder toward the left end, which is the other end, toward the right end, which is the other end. The other end of the clamp rod I6 inserted into the cylinder body 7 is connected to the piston 10, and the left end side of the clamp rod 16 is driven by the hydraulic pressure of the clamp hydraulic oil chamber 9 to the right end side. The object B is press-fixed between the cylinder body 7 and the fixing base A on which the cylinder body 7 is supported.

(Prior Art) In the above-mentioned basic structure, conventionally, as shown in FIG. The return spring 31 was only able to press it toward the left end.

(Problem to be Solved by the Invention) In the above-mentioned conventional technology, there is a problem in that when the hydraulic clamp 5 is unclamped, the fixed object B easily shifts from the fixing base A due to external force acting on the fixed object B. There is.

That is, in the workpiece chuck unit positioning and fixing device for a gear cutting machine shown in FIG.
After the work chuck unit 1 is rotated to a desired rotation position, the hydraulic clamp 5 is driven to clamp and fix the work chuck unit 1 to the fixing base A.

When changing the rotational position of the workpiece chuck unit 1, in the conventional structure shown in FIG.
Pressure oil is discharged from the piston 10, and the piston 10 is returned to the unclamping side at one end by the piston return spring 31. During this unclamping, the piston 10 and clamp rod 16 contract with respect to the clamp body 7, so an unclamping gap C is formed between the fixing base and the workpiece chuck unit 1, and the workpiece chuck unit 1 is suddenly caused by its own weight. There was a risk that the aircraft would turn around.

Therefore, when changing the rotation position, the operator must hold the work chuck unit 1 with one hand to prevent rotation due to its own weight while positioning, which takes time and effort.

Furthermore, if foreign matter such as chips or dust enters the unclamping gap C during the above-mentioned unclamping, the positioning accuracy of the fixed object B with respect to the fixing base A deteriorates, and thus the processing accuracy decreases.

SUMMARY OF THE INVENTION An object of the present invention is to prevent a fixed object from easily shifting due to external force during unclamping, and to maintain good positioning accuracy of the fixed object with respect to a fixing base.

(Means for Solving the Problems) In order to achieve the above object, the present invention is characterized by adding the following improvements to the above basic structure.

For example, Figures 1 to 3, or Figures 4, 5, and 6.
As shown in the figure, the piston], 0 is connected to the other end side (right end side) of the clamp rod 16 via a clamp stroke adjusting means 21 so as to be adjustable in forward and backward movement, and the piston 10 and the clamp are connected from the cylinder body 7 to the other end side (right end side). A preload spring 23 is interposed between the stroke adjusting means 21 and the other end side (right end side) of the clamp rod 16. It is attached so that it is pressed against the other end (right end).

The clamp stroke adjusting means 21 between the piston 10 and the clamp rod 16 can be used either by providing an intermediate member such as a nut member as shown in the figure, or by directly screwing the two 10 and 16 together. A case may be considered in which it is composed of a fitting part.

Further, the preload spring 23 may be interposed between the cylinder body 7 and the piston 10, or between the cylinder body 7 and the clamp stroke i-joint means 21. The location may be at least one location from the cylinder body 7 through the piston 10 and the clamp stroke adjusting means 21 to the other end side of the clamp rod 16.

(effect) The invention works as follows.

When the pressure oil is discharged from the clamp hydraulic oil chamber 9 during unclamping, the piston 1 moves against the cylinder body 7.
The preload spring 23 prevents the preload spring 23 from contracting or contracting by more than a predetermined amount, and the object B is moved to the fixing base A through the cylinder body 7 by the elastic force of the preload spring 23.
Fix it with light friction. This prevents the fixed object B from easily shifting even when an external force such as its own weight is applied.

In addition, since the unclamping gap C during unclamping can be eliminated by the elastic force of the preload spring 23 mentioned above, it is possible to prevent foreign substances such as chips and dust from entering between the fixing base A and the fixed object B. can. As a result, it is possible to maintain good positioning accuracy of the object B relative to the fixing base A.

? (Example) Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show one embodiment thereof.

As shown in the elevational view of FIG. 2, a gear 2, which is a workpiece, is attached to a vertical fixing surface of a fixing base A of a gear cutting machine via a workpiece chuck unit 1, which is an object B. The work chuck unit 1 consists of a unit main body 1a and a flange portion 3. The flange portion 3 is rotatably supported by a fixed base A via a rotation means (not shown), and
It is pressed and fixed at a desired turning position by a plurality of hydraulic clamps 5.

Note that since the unit body portion 1a is inclined with respect to the flange portion 3, the center of gravity G of the workpiece chuck unit 1 is displaced from the center of rotation of the flange portion 3.

The structure of the above-mentioned hydraulic clamp 5 will be explained with reference to a longitudinal sectional view in FIG. 1 and a right side view in FIG. 3.

A clamp hydraulic oil chamber 9 and a piston 10 are provided in the cylinder body 7 of the hydraulic/lintaro in this order from one end, which is the left end, to the other end, which is the right end. A clamp portion 8 is formed on the left side of the cylinder body 7. The piston 10 is slidable in an oil-tight manner on the cylinder body 7 via a pair of O-rings 12 and 13. A pressure oil supply/discharge port 14 is provided on the peripheral wall of the cylinder body 7, facing the clamp hydraulic oil chamber 9.
It is formed through. Further, a scraper 15 made of fluorine resin is fitted to the right end portion of the piston 10.

Additionally, a T-port 16, which is a clamp rod, is inserted between the cylinder main body 7 and the fixing base A. That is, a plurality of T grooves 18 are formed radially in the fixing base A, and the T leg portions 19 of the T port 16 are fitted into the T grooves 18. A nut member 21 serving as a clamp stroke adjusting means is fitted into the male threaded portion 20 at the right end of the T-bolt 16 . By moving this nut member 21 forward or backward with respect to the T-bolt 16, the clamp stroke of the piston 10 is adjusted forward or backward.

Furthermore, the clamp portion 8 of the cylinder body 7 and the piston 10
A preload spring 23 is interposed between the two. This preload spring 23 is made of a ball hair ring web washer, and the piston 10 is connected to the clamp part 8.
and the nut member 21 in order to force the clamp rod 16 to the right.

Note that a nylon locking member 24 is interposed between the male threaded portion 20 of the T-port 16 and the nut member 21. Further, an O-ring 25 is fitted onto the clamp surface of the clamp portion 8 to prevent cutting oil from entering.

The hydraulic clamp 5 described above operates as follows.

When driving the clamp, the pressure oil supply/discharge port 14 is connected to the hydraulic source (not shown).
Pressure oil is supplied to the clamp hydraulic oil chamber 9 through. Then,
The hydraulic pressure causes the piston 1 to move against the cylinder body 7.
0 extends and connects the clamp rod 1 via the nut member 21.
At the same time, the cylinder body 7 is driven to the left by the reaction force of the oil column in the clamp hydraulic oil chamber 9. As a result, the object B to be fixed is pressed and fixed between the fixing base A and the clamp part 8. In addition, during the above-mentioned clamp drive, the preload spring 23 is configured to expand following the expansion movement of the clamp piston 10 and the clamp portion 8.

On the other hand, when unclamping, the pressure oil in the clamp hydraulic oil chamber 9 is discharged from the pressure oil supply/discharge port 14. Then,
The piston 10 contracts with respect to the cylinder body 7, but the elastic force of the preload spring 23 causes the piston 10 to
Push the bolt 16 to the right. As a result, the object to be fixed B
The work chuck 1 is frictionally fixed to the fixed base by the clamp portion 8, and rotation of the work chuck 1 is prevented.

In addition, when maintaining the gear cutting machine, etc., the work chuck unit 1. When removing the T-bolt 1, the nut member 21 is removed from the T-bolt 16, and then the cylinder body 7 and the piston 10 are extracted.

4 to 6 each show a modification of the above embodiment.

In the first modification shown in FIG. 4, a preload spring 23 made of a disc spring is installed between the piston 10 and the throat member 21. Furthermore, the preload spring 23 prevents foreign matter from entering the hydraulic cylinder 6.

In the second modification shown in FIG. 5, the preload spring 23 is composed of a plurality of compression coil holes arranged in the circumferential direction.

In the third modification shown in FIG. 6, the piston 10 is fitted onto the cylinder body 7, a preload spring 23 made of a compression coil spring is interposed between the cylinder body 7 and the throat member 21, and a clamp portion Another preload spring 27 made of a compression coil R is also interposed between the piston 8 and the piston 10.

In the above embodiments and variations, T
Although the nut member 21 is interposed between the male threaded portion 20 of the bolt 16 and the piston 10, instead of this, it is also possible to screw-fit the piston 10 directly to the male threaded portion 20. . In this case, the screw fitting portions of both 20 and 10 constitute the stroke adjusting means of the clamp 1.

(Effects of the Invention) The present invention has the following effects because it is configured and operates as described above.

When unclamping, the object to be fixed is frictionally fixed to the fixing base via the cylinder body by the elastic force of the preload spring.
Even if an external force is applied to the fixed object, the fixed object can be prevented from easily shifting.

Furthermore, since the elastic force of the preload spring eliminates the unclamping gap during unclamping, it is possible to prevent foreign matter such as chips and dust from entering between the fixing base and the object to be fixed. As a result, it is possible to maintain good positioning accuracy of the fixed object with respect to the fixing table, and to improve processing accuracy of the fixed object.

Moreover, since the clamp rod and the piston are connected to each other so as to be freely adjustable forward and backward by the clamp stroke adjusting means, changes in the clamp thickness of the object to be fixed can be easily accommodated.

[Brief explanation of the drawing]

1 to 6 show embodiments of the invention. Figures 1 to 3 show one example of this, and Figure 1 shows the second embodiment.
FIG. 2 is an elevational view showing the state in which the work chuck unit is attached to the gear cutting machine, and FIG. 3 is a right side view of FIG. 1. FIGS. 4 to 6 each show a modification and correspond to FIG. 1. FIG. 7 shows a conventional example and is a diagram corresponding to FIG. 1. 1... Work chuck unit (fixed object B), 6...
...Hydraulic cylinder, 7.. Cylinder body, 9.. Clamp operating oil chamber, 10.. Piston, 16.. Clamp rod (T bolt), 21.. Clamp stroke adjustment means (nut member) , 23...Preload spring, A...fixing base.

Claims (1)

[Claims] 1. A clamp hydraulic oil chamber (9) and a piston (10) are provided in order from one end side to the other end side of the cylinder body (7) of the hydraulic cylinder (6), and the cylinder body (7) Clamp rod (1
6) The other end side is connected to the piston (10), and the clamp rod (1
6) to the other end side, the object to be fixed (B) is pressed and fixed between the fixing base (A) on which one end side of the clamp rod (16) is supported and the cylinder body (7). In the clamp rod direct-acting hydraulic clamp configured as shown in FIG. A preload spring (23) is interposed between the main body (7), the piston (10) and the clamp stroke adjustment means (21), and the other end of the clamp rod (16). 23) is a clamp rod direct-acting hydraulic clamp, characterized in that a clamp rod (16) is attached to the cylinder body (7) so as to press it toward the other end.