JP2646076B2 - Jaw shape of chuck - Google Patents

Description

The present invention relates to a wedge-shaped chuck for a machine tool.

As the spindle speed of machine tools increases with the progress of technology, the force of gripping the workpiece (grasping force)
We need to be more powerful. This is because the grasping force of the jaw itself is reduced by the centrifugal force, and eventually the cutting becomes impossible.

The present invention solves such drawbacks of the chuck splendidly. The first object of the present invention is to make the chuck shape capable of increasing the rigidity of the jaw and withstanding a stronger gripping force. A second object is to make the jaw have the best shape that is most effective for reducing the weight of the jaw.

However, the present invention relates to a wedge-shaped chuck based on a completely new technical concept as described later, and is characterized by a plurality of wedge grooves provided in a body of the chuck.
Two plungers are provided; the plungers are provided with a pair of jaws (V) such that each wedge groove (5) is formed in a space having an inverted T-shaped cross section; Each of the guide grooves of the plurality of jaws is provided with a slot groove (11) at a groove bottom portion. It is formed to have a width narrower than a damaged portion which is easily damaged when being damaged while being deformed, and is provided with an inverted T-shaped protruding portion at an inner end in a radial direction with respect to a body behind the jaw. Is formed solely from one wedge member that bears the surface pressure load and a reinforcement member that exclusively bears the bending load. The reinforcement member is orthogonal to the wedge member and has a width (D) of the wedge member. Formed into a narrower reinforcing member width (C) And the reinforcement member is formed in a slot groove (11) provided at a groove bottom portion of each of the plurality of jaws provided on the body of the chuck at all times. The width (D) of the wedge member is smaller than the width of the jaw;
And the wedge member is mounted radially inward of the body with respect to the reinforcing member, and is inclined radially outward of the body toward the rear, and the reinforcing member extends radially outward of the body. Is to be.

The wedge-shaped chuck according to the present invention is provided with a slot groove in the guide groove of the jaw provided in the body of the chuck, and accommodating the reinforcing member of the projection of the jaw in the slot groove, and adjusting the width of the slot groove to each of the jaws of the plunger. The jaw of the wedge-shaped chuck is formed with a width narrower than the broken part so that the jaw can be supported by the inner surface of the body when a force is applied. The point of view that it was obtained as a result of clearly dividing the functions of the above and that this division was the most useful technical idea to increase the rigidity of the jaw and to reduce its weight, the following excellent effects It is also very important in terms of gain.

Next, a conventional technique relating to such a chuck and a jaw shape will be described.

In conventional chucks, the strength of the plunger is weak,
Further, the conventional jaw shape is a determination of a mechanically strongest shape in a space region limited to the inner diameter of the body center hole. In other words, it is the determination of the mechanically strongest shape within the space limited to the range of the outer diameter of the plunger sliding forward and backward in the axial direction of the body.

Hereinafter, the conventional chuck structure shown in FIGS. 1 to 4 and FIG. 13 will be described in detail. In the figure, the first
The figure is a vertical sectional view of the upper part of the three-jaw chuck. As shown in FIG. 13, a radial guide groove 10 'is provided in the radial direction of the body 1'. Is inserted slidably. A top jaw 3 'is fixed to the front of the master jaw 2' (the front R and S sides of the body 1 ') with bolts (not shown), and a plunger 4' is axially forwardly inserted in a hole at the center of the body 1 '. It is fitted freely without sliding backward.

A wedge groove 5 'is also provided on the outer periphery of the plunger 4' in three equal parts (only one direction is shown) as shown in FIG. 3, and a wedge provided on the inner side of the master jaw 2 '. Meshes with the portion 2 '. The details of the meshing state are shown in FIG. 4, which is an enlarged view cut along the line XX 'of FIG.

The plunger in the chuck having a structure in which the inner portion of the jaw is provided with the engagement means has the following operational disadvantages.

When an operation for grasping the outer diameter of the workpiece (not shown) is performed by the top jaw 3 ', a force indicated by an arrow P acts radially outward on the wedge portion 2'a of the master jaw 2'. Due to the action of this force P, a bending moment M acts on the jaw 4'b of the T-shaped wedge groove 4'a of the plunger 4 'in the direction of the arrow starting from the portion Q where the contact with the hole of the body 1' separates. I do. When the acting force P further increases, the portion receives stress concentration and breaks like the zigzag line 6 progresses. Naturally, when the separated portion Q is not used as a base point, the zigzag line 6 is broken in the 45-degree direction from the weakest notch portion of the T-shaped wedge groove 4'a.

However, the mechanical strength of the jaw in such a chuck structure should be the shape of the wedge portion 2'a that can sufficiently withstand the acting force P. However, as is clear from FIG. 2, the shape of the wedge portion 2'a does not extend beyond the space defined by the inner diameter of the body center hole. In other words, the shape does not protrude into the space limited by the outer diameter of the plunger. Such a shape limitation has a limitation on the mechanical strength from the beginning for the reason described later.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a longitudinal sectional view of the three-jaw chuck, FIG. 6 is an enlarged partial view of the body 1 viewed from an oblique direction, FIG. 7 is a perspective view of the master jaw 2, and FIG. FIG. 9 is a perspective view of the plunger 4 taken along the line Y '.

As shown in FIG. 6, a guide groove 10 for inserting a master jaw 2 from the inside in the direction of arrow Z to the outside in the radial direction is equally divided into three parts (1) in the integrally formed body 1. Direction is shown in the drawing), and a slot having a fixed length K and a width A at the bottom of the guide groove 10 is smaller than the groove width and leaves an appropriate amount of thick portion W toward the outside in the radial direction. A groove 11 is provided, and the body 1 of the guide groove 10 and the slot groove 11 is provided.
An opening for inserting a jaw from the inside of the body at the time of assembly is formed in the inner peripheral surface of the body. The slot groove 11 has a seventh
A part of the reinforcing member 60 constituting the protruding portion 12 of the master jaw 2 shown in the drawing can be always accommodated.

In the above-mentioned embodiment, the device for making the grasping force stronger than before is to improve the mechanical rigidity and strength of the protrusion 12 provided on the radially inner side of the body 1 behind the master jaw 2. To increase.

A specific example of this will be described with reference to FIG. As shown in the drawing, the master jaw 2 is provided with a wedge portion 12 having a protrusion at a radially inner end with respect to the body 1 behind the master jaw 2. The wedge portion 12 has a wedge member 50 having a width smaller than the width of the jaw 2 which generates a wedge action when engaged with the wedge groove 5 of the plunger 4 shown in FIG.
The reinforcing member 60 is orthogonal to the wedge member and extends outward in the body radial direction with a width smaller than the width of the wedge member. The reinforcing member 60 mechanically reinforces the wedge member. To the center hole side of the body 1
The reinforcement member 60 is inclined radially outward of the body toward the rear and extends radially outward. The cut end face shape of the wedge portion 12 is formed in an inverted T shape, and the wedge member 50 exclusively bears the surface pressure load at the time of engagement, whereas the reinforcing member 60 exclusively bears the bending load at the time of engagement. To carry.

However, the required shape of the reinforcing member 60 is such that its sectional modulus Z is large so as to be effective for a bending load at the time of meshing, that is, in terms of a mechanical calculation formula, the width is C, and the protrusion is when the tall longitudinal jaw 12 and the ^{L, Z = CL 2/6} (C, L seventh shown) is to increase the L in. That is, it is desirable that the length L is larger than the width C from the viewpoint of a mechanical function.

In the present embodiment, the slot is formed from the inside of the body 1 in the radial direction.
By forming the reinforcing member 60 having a portion formed in the outer slot groove 11 and forming the reinforcing member 60, the above-described dimension L can be made extremely large. On this occasion,
The length L in the longitudinal direction of the jaw of the reinforcing member 60 is formed in a shape that gradually decreases as it goes in the protruding direction of the protrusion, so that the length L substantially corresponds to the bending moment.
However, apart from the fact that the shape of the outer end face of the reinforcing member 60 is not straight as shown in FIG.
It may be similar to a mechanically reasonable bending moment diagram curve.

Further, since the width D of the wedge member is formed smaller than the width of the jaw, the guide surface gs of the jaw guided to the body can be secured over the entire length of the jaw body in the radial direction, and the grasping accuracy is improved. 7 in the figure, the wedge member 50 the base surface 100 to increase the round-trip length of the plunger is not a guide surface, it is possible, as shown by a chain line 1 ₁ of Fig. the shorter the round trip length of the plunger).

Furthermore, the width D of the wedge member, as shown by a chain line 1 ₂ of Figure 8
Is wider, the base of the jaw V of the plunger 4 forming the wedge groove 5 becomes thinner and the jaw V becomes weaker. However, since the width of the wedge member is formed narrow as in the present invention, the jaw V becomes Become stronger. In addition, if the width D of the wedge member is reduced, the weight of the protruding portion 12 is reduced and the jaw is reduced in weight, so that the chuck can be rotated at high speed.

This embodiment is constructed as described above, and the plunger 4 is slid forward and backward in the axial direction of the body by the operation of a cylinder (not shown). When the outer diameters of the workpieces are grasped by simultaneously operating the jaws 3, a radially inward force acts on the wedge portions 12 of the respective master jaws 2. Thus, the acting force is divided into an acting component (surface load) for pressing and breaking the wedge member 50 of the wedge portion 12 and an acting component (bending load) for bending and breaking the reinforcing member of the wedge portion 12. Is done.

On the other hand, when grasping the inner diameter of the workpiece, a force outward in the radial direction acts on the wedge portion 12, and the surface pressure load component and the bending load component in the opposite direction different from the grasp of the outer shape. It is divided and carried.

When this is examined as the strength of the master jaw 2, the mechanical strength of the wedge member 50 may be an area having a dimension sufficient to withstand the surface pressure load, and the mechanical strength of the reinforcing member 60 is It is sufficient if the strength is sufficient to withstand the bending load. Since the reinforcing member 60 constituting the wedge portion 12 of the present embodiment has a feature of being provided with a portion to be accommodated in the slot groove 11 of the body 1,
A considerably large section modulus Z can be obtained, and it can sufficiently withstand an excessive bending load. In FIG. 7, the length L can be made much larger than that of the conventional one, so that it is superior to the conventional one.

As described in detail above, this embodiment is excellent in a rational viewpoint from which the function of the wedge portion 12 is deeply observed from an engineering point of view, and the shape of the wedge portion 12 maximizes the mechanical strength. In addition, the jaw 2 including the wedge portion 12 is extremely excellent in improving the strength and rigidity of the entire jaw 2.

The outer peripheral surface G of the plunger 4 is formed in an arc to the edge of the wedge groove 5 as shown in FIG. 9, and when the wedge groove 5 is engaged with the wedge portion 12 of the master jaw 2, the wedge groove 5 The one that comes into contact with the stem of the portion 12 is desirable from the viewpoint of forming a bearing surface described later. This means that even if a part of the arc is cut, the cutting width H should be smaller than the width D of the wedge member of the master jaw 2 as shown in FIG.

Another measure to further increase the gripping force is that the entire radially outer end portion of the reinforcing member 60 protrudes further outward than the space area limited to the outside range of the plunger, and the body 1 Slot groove that can penetrate deep inside
That is, the structure of the body 1 including the eleventh structure is provided.

Next, when examining the mechanical strength on the plunger 4 side, the plunger 4 receives the above-mentioned reaction force of the component force of the surface pressure load on the jaw surface T of the jaw V of the projecting member forming the wedge groove 5. Due to the structure, the overhang member is formed in a shape having a size that can sufficiently withstand the reaction force of the component force of the surface pressure load. However, when the gripping force of the workpiece is further increased to increase the load to be carried, the overhanging member receives a bending moment M in the direction of arrow P as shown in FIG. Occur.
In such a case, since the outer peripheral surface G of the jaw V is supported by the inner peripheral surface F near the slot groove 11 and the bearing surface is formed, breakage like the zigzag line 6 in FIG. 4 does not progress at all. It is. However, it is needless to say that the bearing surface is desirably formed to have a structure formed in the entire movement range of the plunger 4.

At this time, if the slot groove width A is formed to have a width smaller than a damaged portion which is easily damaged when each of the jaws V is deformed and damaged by the action of the bending force, the outer peripheral surface G of the jaw V Can be supported under the inner peripheral surface of the body. In FIG. 8, the width is set to be approximately equal to the width C of the reinforcing portion 60 within a range in which the sliding motion of the master jaw 2 in the radial direction is not affected.
The gap between the plunger and the inner peripheral surface of the body is set to a minimum within a range in which the plunger 4 can slide in the axial direction, and forms a bearing surface. The processing of the slot groove 11 is such that the rigidity of the body 1 is not affected at all by forming the shape toward the outside in the radial direction and leaving the wall thickness.

In order to strengthen the grasping power, the wedge part
The size of the length L, which is integrally fixedly joined to the 12, can be selected to be large or small according to the increase or decrease of the acting force. Also in this regard, the jaw shape of this embodiment is excellent, and the fact that the length L can be freely selected means that mechanical considerations must be taken into account both in increasing the section modulus and in reducing the shape factor. It is excellent in that the obtained remarkable effect is obtained.

This new technical idea solves the two aspects of improving the rigidity of the jaw and reducing the weight of the jaw, which have been considered difficult in the past.

In the present embodiment, the shape of the reinforcing member 60 as shown in FIG. 7 is formed as a plane gradually decreasing from the jaw toward the tip, or a curved surface (not shown) in consideration of the shape coefficient is used to further reduce the weight. It may be something. Further, in FIG. 7 of this embodiment, the maximum length L of the wedge portion 12 in the master jaw 2 is set to about half of the jaw length. The first reason for this is that if a section modulus of sufficient strength can be obtained mechanically, an unnecessarily long reinforcing member is required.
This is because the weight of the wedge portion 12 is made lighter without the necessity of 60, so that a decrease in gripping force due to centrifugal force is minimized. The second reason is to reduce the cutout portion of the slot groove 11 in the body 1 and improve the rigidity of the body. In addition, the slot groove 11 is also effective for ensuring the safety that the master jaw is not scattered to the outside even if each wedge portion of the plunger or the master jaw is damaged during rotation.

The shape of the wedge groove of the plunger corresponding to the jaw is formed as shown in FIGS. 11 and 12 in addition to a simple inverted T-shape as shown in FIG. In addition, the roof can be formed into a rational gable-shaped roof shape corresponding to the bending moment of the load to further enhance the strength of safety.

Since the present invention is configured as described above, it is possible to provide an extremely strong jaw that cannot be obtained by the conventional technology, and has a strong grasping power and high precision. It is also possible to provide a chuck. Furthermore, since the wedge member at the wedge portion of the jaw can be made extremely thin, a chuck having a large through-hole diameter for inserting a workpiece can be provided, and furthermore, an extremely long stroke type chuck having a very large jaw movement amount in the radial direction. It also has an excellent effect. In particular, it is effective for increasing the cutting speed and improving the accuracy associated with the increase in the cutting speed, and also exhibits an excellent effect of reducing the inertia force of the master jaw.

[Brief description of the drawings]

1 to 4 show a conventional structure, FIG. 1 is an upper vertical sectional view of a chuck, FIG. 2 is a perspective view of a master jaw, FIG. 3 is a partial perspective view of a plunger, and FIG. 5 is an enlarged view cut along the line XX 'of FIG. 1, FIGS. 5 to 13 show a specific embodiment, FIG. 5 is a longitudinal sectional view of the chuck, and FIG. 6 is a partial perspective view of the body. , FIG. 7 is a perspective view of the master jaw, FIG. 8 is an enlarged view cut along the line YY ′ of FIG. 5, FIGS. 9 and 10 are partial perspective views of the plunger, and FIGS. 5 shows another example of a wedge groove shape of a plunger. FIG. 13 is a partial perspective view of a body showing a conventional structure. 1 Body 2 Master jaw 3 Top jaw 4 Plunger 5 Wedge 12 Projection 10 Guide groove 11 Slot groove 50 Wedge member 60 Reinforcement members

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho-53-99081 (JP, U)

Claims (1)

(57) [Claims] 1. An integrated body having a body center hole and a plurality of guide grooves in a radial direction and having an opening in an inner peripheral surface of the body center hole so that a jaw can be inserted from the inside during assembly.
One plunger having a plurality of wedge grooves corresponding to the guide grooves by sliding forward and backward in the axial direction of the body center hole; A wedge-shaped chuck in which a chuck comprising a plurality of jaws slidably moving outward and outward has a jaw having the following shape. (A) The plunger has a pair of jaws (V) such that each wedge groove (5) is formed in a space having an inverted T-shaped cross section. (A) A plurality of jaws provided on the body. Each guide groove is provided with a slot groove (11) at a groove bottom portion, and the width of the slot groove (11) is such that each of the pair of jaws (V) is deformed by the action of a bending force. (C) a radially inner end of the rear part of the jaw with respect to the body, which has an inverted T-shaped protruding portion; The portion is formed solely of one wedge member that bears the surface pressure load and a reinforcing member that bears the bending load exclusively; (d) the reinforcing member (60) is orthogonal to the wedge member (50). And the width (C) of the reinforcing member is smaller than the width (D) of the wedge member. And it is formed into a shape extending in the radial direction of the body with which, (e) the reinforcing member (60) said slot grooves (11)
(F) the width (D) of the wedge member is smaller than the width of the jaw; and (g) the wedge member is mounted radially inward of the body with respect to the reinforcing member. The body is inclined radially outward of the body toward the rear, and the reinforcing member extends radially outward of the body.