JPS6237619Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a clamp cylinder for a jig, and its purpose is to provide an accumulator function to the clamp cylinder itself.

In recent years, machining centers have been widely used as machining devices that can perform various machining operations on a workpiece without changing the position of the workpiece. The first workpiece mounting stand in such a machining center.
As shown in the figure, a plurality of hydraulic clamp cylinders Hc are embedded or placed at appropriate intervals in a jig pallet P having a T-shaped groove Tc extending vertically and horizontally, communicating with an internal hydraulic flow path, and forming a pallet. Proposals have been made to make effective use of the entire area. In addition, J ₁
and J ₂ is in the pallet changer P/C,
This is a joint that connects the hydraulic source S side and the pallet P side, and l is a pressure intensifier.

However, in such a jig, the pallet
P ₁ is jointed with the hydraulic source S side at the machining position.
Since they are separated by J ₁ and J ₂ , if an oil leak occurs at even one point in the hydraulic passage system in pallet P ₁ , the full hydraulic clamp cylinder Hc connected to it
This may cause the tightening force to decrease. Therefore,
It has been proposed to add an accumulator Ac so that even if a small amount of oil leaks, there will be no problem (see Japanese Patent Application No. 58-41235).

The present invention uses a return spring and an elastic body with a very large spring constant to operate the presser foot, in place of the above-mentioned accumulator or in combination with the accumulator, in order to further ensure the operational stability of the hydraulic clamp cylinder. It is an object of the present invention to provide a clamp cylinder for a jig in which a cylinder rod is operated in two stages and the hydraulic clamp cylinder itself has an accumulator function.

Hereinafter, the present invention will be described with reference to the accompanying drawings showing two typical embodiments thereof.

FIG. 2 is a cross-sectional view of a push-hand type hydraulic clamp cylinder, and FIG. 3 is a cross-sectional view of a push-hand and pull-hand type hydraulic clamp cylinder.

In FIG. 2, reference numeral 1 denotes a cylinder chamber, in which a cylinder rod 2 for operating a presser foot 10 is housed via a tightening bolt 11 so as to reciprocate by l, and the upper opening of the cylinder chamber 1 is an annular stopper 6. has been closed by.

The cylinder rod 2 is equipped with an annular piston body 3 for receiving the hydraulic pressure of high-pressure oil flowing into the cylinder chamber 1 through a port 7 in the cylinder wall to move the cylinder rod 2 forward. An annular piston body 3 is attached to the cylinder rod 2 so as to be slidable along the rod axis, and is prevented from coming off by a snap spring 8, and its sliding stroke is limited to Δl by a snap spring 9.

Furthermore, the annular piston body 3 is biased in the backward direction by an elastic body having a very large spring constant, such as a disc spring 5, disposed between it and the stop ring 9. A return spring 4 is disposed between the stopper 6 and the cylinder rod 2 as a whole, so that the entire cylinder rod 2 is biased in the backward movement direction.

Therefore, when high-pressure oil is introduced into the cylinder chamber 1 and acts on the piston body 3, the return spring 4 takes priority over the disc spring 5 until the presser foot 10 comes into contact with the workpiece W via the tightening bolt 11. Reduce it and push up the cylinder rod 2. Next, in order to tighten the workpiece W with the presser foot 10, the cylinder rod 2 is
When attempting to push up the cylinder rod 2, the cylinder rod 2 immediately comes into complete contact with the workpiece W, and the upward movement of the cylinder rod 2 is completely restricted, so the annular piston body 3 begins to slide on the cylinder rod 2 against the disc spring 5. This disc spring 5 has a very large spring constant, so the work W
When the tightening is completed, its reduced form stores hydraulic pressure, that is, it has an accumulator function, and even if oil leaks in the hydraulic flow path on the pallet P side, the entire clamp cylinder Hc on the pallet P Since the oil pressure drop is compensated for, the workpiece clamping force of each clamp cylinder Hc hardly decreases, and the operational stability of the clamp cylinders is significantly improved.

The specific example shown in Fig. 3 is almost the same as Fig. 2, but in contrast to the case of Fig. 2 which is a push type,
In the case of FIG. 2, there is an advantage that by reversing the handle, the pushing hand (when the 2a side is used) and the pulling hand (when the 2b side is used) can be freely selected. Note that since other points are the same as those in FIG. 2, the same parts are given the same numbers and their explanations will be omitted.

The present invention has been explained above based on specific examples, but in addition to return springs, elastic bodies with extremely large spring constants, such as disc springs and polymeric elastic bodies, can generate a large repulsive force by small deformation. Various modifications can be made without departing from the gist of the present invention, which uses an elastic body to provide the clamp cylinder itself with an accumulator function. Further, even when using a clamp cylinder having an accumulator function, operational stability can be further improved by separately attaching an accumulator. Further, in this case, the capacity of the accumulator may be small, which has the advantage of eliminating problems such as installation space and cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the state of replacement of the newly proposed jig pallet, and FIGS. 2 and 3 are cross-sectional views of the jig clamp cylinder according to the present invention. In addition, 1 is a cylinder chamber, 2 is a cylinder rod, 3 is an annular piston body, 4 is a return spring, and 5 is an elastic body.

Claims (1)

[Scope of utility model registration request] A cylinder rod 2 for operating a presser foot that can reciprocate within the cylinder chamber 1 with a stroke l has an annular piston body 3 on the rod shaft that receives the hydraulic pressure of high-pressure oil introduced into the cylinder chamber 1 and moves the cylinder rod 2 forward. While the return spring 4 urges the entire cylinder rod 2 in the backward movement direction via the annular piston body 3, the return spring 4 has a spring constant larger than that of the return spring 4. 1. A clamp cylinder for a jig having an accumulator function, characterized in that an elastic body 5 having an accumulator function is interposed between a cylinder rod 3 and an annular piston body 3 to urge the annular piston body 3 in a backward movement direction.