Chuck jaw for three-jaw chuck of machine tool

Abstract

The utility model provides a chuck jaw for a three-jaw chuck of a machine tool, which comprises a jaw base, a support and jaw clamping blocks, and is characterized in that the support is a horizontally arranged arch, the middle of the arch is fixed at the top end of the jaw base, and two side arms of the arch extend towards two sides of the jaw base to form openings; the opening direction faces the clamping position of a workpiece, the number of the clamping jaw clamping blocks on each support is two, an upper clamping contact point and a lower clamping contact point are arranged on each clamping jaw clamping block, the supports are in shaft connection with the top ends of the clamping jaw bases, can swing left and right at the top ends of the clamping jaw bases and are adjustable in angle, and the clamping jaw clamping blocks are in shaft connection with the end portions of side arms of the supports and can swing left and right at the top ends of the clamping jaw bases. The swing arm can swing up and down at the end of the side arm, and the angle is adjustable. On the premise of ensuring that a workpiece is clamped by the clamping jaw and ensuring safe production, the number of clamping contact points is increased, and each clamping contact point is ensured to be adjustable in angle and be in full contact with the workpiece, so that clamping deformation of the workpiece is reduced, and the precision of a machining surface of the workpiece is improved.

Description

Technical Field:

[0002] The utility model relates to the technical field of metal cutting machine tools, in particular to a chuck jaw for a three-jaw chuck of a machine tool. Background Art:

[0004] A three-jaw chuck is a mechanical device used on a machine tool to clamp a workpiece. It clamps and positions the workpiece by the radial movement of three movable chucks evenly distributed on the chuck body. However, when the workpiece is a thin-walled cylindrical casting (with a draft angle on its outer surface), since the clamping part of the chuck on the outer wall of the cylindrical casting is a relatively small surface, and a large cutting force is generated when turning the inner hole of the workpiece. To prevent the workpiece from shifting or being thrown out of the machine tool under the action of the cutting force, the chuck must apply a large clamping force to the workpiece. Currently, there is a problem that the clamping force at the clamping part is too large, resulting in the deformation of the cylinder. Although the cylindricity accuracy of the inner hole of the workpiece meets the requirements after machining, after the workpiece is released, the clamping force disappears, and the deformation caused by the clamping force rebounds, resulting in a decrease in the cylindricity accuracy of the inner hole of the workpiece.

[0005] The main reasons for the deformation of the cylindrical workpiece are:

[0006] 1. The number of clamping contact points between the chuck jaw and the workpiece is small: Currently, a large clamping force can only be evenly distributed among the 3 chucks, and there is only 1 clamping contact point between each chuck jaw and the workpiece. Therefore, the clamping force at the clamping contact points is relatively large, which easily causes the inner wall of the cylinder to deform along the direction of the clamping force.

[0007] 2. The angle between the chuck jaw and the workpiece is not adjustable, resulting in a point contact easily occurring at the contact part between the chuck jaw and the workpiece during clamping: Point contact is prone to loosening and has a large local pressure on the workpiece. To avoid the workpiece from shifting or even being thrown out of the machine tool, a larger clamping force is required, further increasing the pressure at the contact point and leading to deformation. Summary of the Invention:

[0009] In order to increase the number of clamping contact points while ensuring that the workpiece is clamped by the jaws and ensuring safe production, and to ensure that each clamping contact point is adjustable in angle and can fully contact the workpiece, thereby reducing the clamping deformation of the workpiece and improving the accuracy of the machined surface of the workpiece, the present utility model provides a chuck jaw for a machine tool three-jaw chuck, which is composed of a jaw base, a bracket and a jaw clamping block. The jaw base is vertically fixed on the chuck body, the bracket is horizontally fixed at the top of the jaw base, and the jaw clamping block is fixed at the end of the bracket for clamping the workpiece to be machined. The characteristics are as follows: the bracket is an arch horizontally arranged, the middle part of the arch is fixed at the top of the jaw base, and the two side arms of the arch extend towards both sides of the jaw base to form an opening, and the opening direction faces the clamping position of the workpiece. There are 2 jaw clamping blocks on each bracket, which are respectively fixed at the ends of the two side arms of the bracket. There are 2 upper and lower clamping contact points on each jaw clamping block, that is, the total number of the clamping contact points on each bracket is 4.

[0010] The middle part of the arch of the bracket is pivotally connected to the top of the jaw base, and the bracket can swing left and right at the top of the jaw base, thereby adjusting the angle between the bracket and the workpiece, so that the 2 jaw clamping blocks at both ends of the bracket can fully contact the workpiece; the jaw clamping block is pivotally connected to the end of the side arm of the bracket and can swing up and down at the end of the side arm, thereby adjusting the angle between the jaw clamping block and the workpiece, so that the 2 upper and lower clamping contact points on the jaw clamping block can fully contact the workpiece.

[0011] The middle part of the arch of the bracket is pivotally connected to the top of the jaw base through a bracket positioning shaft. The tail of the bracket positioning shaft is embedded and fixed inside the top of the jaw base. The bracket is sleeved on the head of the bracket positioning shaft and can swing left and right around the bracket positioning shaft.

[0012] The jaw clamping block is pivotally connected to the end of the side arm of the bracket through a jaw positioning shaft. The tail of the jaw positioning shaft is embedded and fixed inside the front end of the side arm. The jaw clamping block is sleeved on the head of the jaw positioning shaft and can swing up and down around the jaw positioning shaft.

[0013] On the outer vertical surface of the arched middle part of the bracket, that is, the outer surface of the bracket, and on the outer vertical surface of the claw base, that is, the outer surface of the base. Both the outer surface of the bracket and the outer surface of the base are rectangular surfaces. The outer surface of the bracket protrudes from the outer surface of the base. At the bottom end of the outer surface of the bracket, a rectangular bracket limiting plate is welded. The bracket limiting plate extends downward from the outer surface of the bracket and forms a bracket limiting gap with the outer surface of the base. The width of the bracket limiting gap is less than half of the horizontal side length of the bracket limiting plate. When the bracket swings left and right around the bracket positioning axis, the bracket limiting plate is driven to swing left and right. The bracket limiting plate will contact the outer surface of the base. When the bracket limiting plate touches the outer surface of the base, the bracket limiting plate cannot continue to swing, thereby limiting the swing amplitude of the bracket.

[0014] On the outer vertical surface of the claw clamping block, that is, the outer surface of the clamping block, and on the outer vertical surface of the side arm of the bracket, that is, the outer surface of the bracket side arm. Both the outer surface of the clamping block and the outer surface of the bracket side arm are rectangular surfaces. The outer surface of the bracket side arm extends to its end to form an extended convex plate. A clamping block limiting gap is formed between the extended convex plate and the outer surface of the clamping block. The width of the clamping block limiting gap is less than half of the vertical side length of the outer surface of the clamping block. When the claw clamping block swings up and down around the claw positioning axis, the outer surface of the clamping block will contact the extended convex plate. When the outer surface of the clamping block touches the extended convex plate, the claw clamping block cannot continue to swing, thereby limiting the swing amplitude of the claw clamping block.

[0015] The bracket positioning axis is fixed inside the top end of the claw base through a bracket screw provided inside it, and the claw positioning axis is fixed inside the front end of the side arm through a claw screw provided inside it.

[0016] Both the bracket positioning axis and the claw positioning axis are stepped shafts, and a clamping platform is provided at the top end of their heads. The diameter of the clamping platform is larger than the diameter of the shaft part. The clamping platform is used to limit the axial displacement of the bracket or the claw clamping block on the bracket positioning axis or the claw positioning axis respectively.

[0017] On the upper side plane of the front end of the side arm of the bracket, a spring piece is fixedly provided. The end of the spring piece is fixed on the upper side plane of the front end of the side arm through a screw. The front end of the spring piece extends to the upper side plane of the claw clamping block and fits with the upper side plane of the claw clamping block. The fitting position is at the end of the claw clamping block. When the claw clamping block is not in the clamping state, under the pressure of the spring piece, it is ensured that the upper side plane of the claw clamping block is parallel to the upper side plane of the side arm of the bracket.

[0018] Advantages of the present utility model:

[0019] The bracket can swing around the bracket positioning axis, so that the clamping blocks on both sides of the bracket can fully contact the workpiece.

[0020] The clamping block of the jaw can swing around the jaw positioning axis, so that each clamping contact point can fully contact the workpiece.

[0021] A total of three pairs of such jaws are installed on the chuck body, so there are twelve clamping contact points contacting the outer circle surface of the workpiece. The total clamping pressure is evenly distributed among the twelve contact points, and the deformation amount of each contact point is only one-fourth of that of the conventional jaw, greatly improving the machining accuracy of the workpiece. Brief Description of the Drawings:

[0023] Figure 1 It is the left view of the present invention.

[0024] Figure 2 It is the top view of the present invention.

[0025] Figure 3 It is the schematic diagram of the swing of the bracket of the present invention.

[0026] Figure 4 It is the schematic diagram of the swing of the clamping block of the jaw of the present invention.

[0027] Reference Signs in the Drawings:

[0028] 1. Jaw base; 2. Bracket; 3. Clamping block of the jaw; 4. Side arm; 5. Clamping contact point

[0029] 6. Bracket positioning axis; 7. Jaw positioning axis; 8. Outer surface of the bracket; 9. Outer surface of the base

[0030] 10. Bracket limit plate; 11. Bracket limit gap; 12. Outer surface of the clamping block

[0031] 13. Outer surface of the side arm of the bracket; 14. Extended convex plate; 15. Clamping block limit gap

[0032] 16. Bracket screw; 17. Jaw screw; 18. Chuck table; 19. Spring piece Detailed Description of the Invention:

[0034] As Figures 1 - 4 shown, the present invention provides a chuck jaw for a three-jaw chuck of a machine tool, which is composed of three parts: a jaw base 1, a bracket 2 and a clamping block 3 of the jaw. The jaw base 1 is vertically fixed on the chuck body, the bracket 2 is horizontally fixed at the top of the jaw base 1, and the clamping block 3 of the jaw is fixed at the end of the bracket 2 for clamping the workpiece to be machined. Its characteristics are:

[0035] The bracket 2 is an arch set horizontally. The middle part of the arch is fixed at the top end of the jaw base 1. The two side arms 4 of the arch extend towards both sides of the jaw base 1 to form an opening, and the opening direction faces the clamping position of the workpiece. There are 2 jaw clamping blocks 3 on each bracket 2, which are respectively fixed at the ends of the two side arms 4 of the bracket 2. There are 2 upper and lower clamping contact points 5 on each jaw clamping block 3, that is, the total number of clamping contact points 5 on each bracket 2 is 4.

[0036] The middle part of the arch of the bracket 2 is pivotally connected to the top end of the jaw base 1. The bracket 2 can swing left and right at the top end of the jaw base 1, so as to adjust the angle between the bracket 2 and the workpiece, so that the 2 jaw clamping blocks 3 at both ends of the bracket 2 can fully contact the workpiece; the jaw clamping block 3 is pivotally connected to the end of the side arm 4 of the bracket 2 and can swing up and down at the end of the side arm 4, so as to adjust the angle between the jaw clamping block 3 and the workpiece, so that the 2 upper and lower clamping contact points 5 on the jaw clamping block 3 can fully contact the workpiece.

[0037] The middle part of the arch of the bracket 2 is pivotally connected to the top end of the jaw base 1 through a bracket positioning shaft 6. The tail of the bracket positioning shaft 6 is embedded and fixed inside the top end of the jaw base 1. The bracket 2 is sleeved on the head of the bracket positioning shaft 6 and can swing left and right around the bracket positioning shaft 6.

[0038] The jaw clamping block 3 is pivotally connected to the end of the side arm 4 of the bracket 2 through a jaw positioning shaft 7. The tail of the jaw positioning shaft 7 is embedded and fixed inside the front end of the side arm 4. The jaw clamping block 3 is sleeved on the head of the jaw positioning shaft 7 and can swing up and down around the jaw positioning shaft 7.

[0039] The outer vertical surface of the middle part of the arch of the bracket 2, that is, the bracket outer surface 8, the outer vertical surface of the jaw base 1, that is, the base outer surface 9, both the bracket outer surface 8 and the base outer surface 9 are rectangular surfaces. The bracket outer surface 8 protrudes from the base outer surface 9. A rectangular bracket limit plate 10 is welded at the bottom end of the bracket outer surface 8. The bracket limit plate 10 extends downward from the bracket outer surface 8 and forms a bracket limit gap 11 with the base outer surface 9. The width of the bracket limit gap 11 is less than half of the horizontal side length of the bracket limit plate 10. When the bracket 2 swings left and right around the bracket positioning shaft 6, it drives the bracket limit plate 10 to swing left and right. When the bracket limit plate 10 touches the base outer surface 9, the bracket limit plate 10 cannot continue to swing, thereby restricting the swing amplitude of the bracket 2.

[0040] On the outer vertical surface of the jaw clamping block 3, namely the outer surface 12 of the clamping block, and on the outer vertical surface of the side arm 4 of the bracket 2, namely the outer surface 13 of the bracket side arm, both the outer surface 12 of the clamping block and the outer surface 13 of the bracket side arm are rectangular surfaces. The outer surface 13 of the bracket side arm extends towards its end to form an extended raised plate 14. A clamping block limiting gap 15 is formed between the extended raised plate 14 and the outer surface 12 of the clamping block. The width of the clamping block limiting gap 15 is less than half of the vertical side length of the outer surface 12 of the clamping block. When the jaw clamping block 3 swings up and down around the jaw positioning shaft 7, the outer surface 12 of the clamping block will contact the extended raised plate 14. When the outer surface 12 of the clamping block touches the extended raised plate 14, the jaw clamping block 3 cannot continue to swing, thereby restricting the swing amplitude of the jaw clamping block 3.

[0041] The bracket positioning shaft 6 is fixed inside the top end of the jaw base 1 through a bracket screw 16 provided inside it, and the jaw positioning shaft 7 is fixed inside the front end of the side arm 4 through a jaw screw 17 provided inside it.

[0042] Both the bracket positioning shaft 6 and the jaw positioning shaft 7 are stepped shafts, and a retaining collar 18 is provided at the top end of their heads. The diameter of the retaining collar 18 is greater than the diameter of the shaft portion. The retaining collar 18 is used to limit the axial displacement of the bracket 2 or the jaw clamping block 3 on the bracket positioning shaft 6 or the jaw positioning shaft 7 respectively.

[0043] On the upper side plane at the front end of the side arm 4 of the bracket 2, a spring piece 19 is fixedly provided. The end of the spring piece 19 is fixed to the upper side plane at the front end of the side arm 4 through a screw. The front end of the spring piece 19 extends to the upper side plane of the jaw clamping block 3 and fits with the upper side plane of the jaw clamping block 3. The fitting position is at the end of the jaw clamping block 3. When the jaw clamping block 3 is not in the clamping state, under the pressure of the spring piece 19, it is ensured that the upper side plane of the jaw clamping block 3 is parallel to the upper side plane of the side arm 4 of the bracket 2.

[0044] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A chuck jaw for a three-jaw chuck of a machine tool, comprising a jaw base (1), a bracket (2) and a jaw clamping block (3), wherein the jaw base (1) is vertically fixed on the chuck body, the bracket (2) is horizontally fixed on the top of the jaw base (1), and the jaw clamping block (3) is fixed on the end of the bracket (2) for clamping a workpiece to be processed, wherein: The bracket (2) is in the shape of a horizontally arranged arch, the middle part of the arch is fixed to the top of the clamping jaw base (1), the two side arms (4) of the arch extend to the two sides of the clamping jaw base (1) to form an opening, the opening direction is toward the clamping position of the workpiece, each of the brackets (2) has two clamping jaw clamping blocks (3), which are respectively fixed to the ends of the two side arms (4) of the bracket (2), and each of the clamping jaw clamping blocks (3) is provided with two upper and lower clamping contact points (5), that is, the total number of the clamping contact points (5) on each bracket (2) is four; The arched middle part of the bracket (2) is axially connected to the top of the clamping claw base (1), and the bracket (2) can swing left and right at the top of the clamping claw base (1), thereby adjusting the angle between the bracket (2) and the workpiece, so that the two clamping claw clamping blocks (3) at both ends of the bracket (2) can fully contact the workpiece; the clamping claw clamping block (3) is axially connected to the end of the side arm (4) of the bracket (2), and can swing up and down at the end of the side arm (4), thereby adjusting the angle between the clamping claw clamping block (3) and the workpiece, so that the upper and lower two clamping contact points (5) on the clamping claw clamping block (3) can fully contact the workpiece.

2. The chuck jaws for a three-jaw chuck of a machine tool according to claim 1, characterized in that: The arched middle portion of the bracket (2) is axially connected to the top end of the claw base (1) via a bracket positioning shaft (6); the tail end of the bracket positioning shaft (6) is embedded in the top end of the claw base (1) and fixed; the bracket (2) is sleeved on the head end of the bracket positioning shaft (6) and can swing left and right around the bracket positioning shaft (6); The claw clamping block (3) is axially connected to the end of the side arm (4) of the bracket (2) via a claw positioning shaft (7); the tail of the claw positioning shaft (7) is embedded in the front end of the side arm (4) and fixed; the claw clamping block (3) is sleeved on the head of the claw positioning shaft (7) and can swing up and down around the claw positioning shaft (7).

3. The chuck jaws for a three-jaw chuck of a machine tool according to claim 2, characterized in that: The outer facade of the arched middle part of the bracket (2), i.e., the bracket outer facade (8), and the outer facade of the claw base (1), i.e., the base outer facade (9), are both rectangular surfaces, the bracket outer facade (8) protrudes from the base outer facade (9), and a rectangular bracket limiting plate (10) is welded to the bottom end of the bracket outer facade (8), and the bracket limiting plate (10) extends downward from the bracket outer facade (8) and forms a bracket limiting plate with the base outer facade (9). The support limit gap (11) has a width that is less than half of the length of the side of the support limit plate (10) in the horizontal direction. When the support (2) swings left and right around the support positioning axis (6), the support limit plate (10) is driven to swing left and right. The support limit plate (10) will contact the outer facade (9) of the base. When the support limit plate (10) touches the outer facade (9) of the base, the support limit plate (10) cannot continue to swing, thereby limiting the swing amplitude of the support (2).

4. The chuck jaws for a three-jaw chuck of a machine tool according to claim 2, characterized in that: The outer facade of the clamping block (3) of the clamping claw is the clamping block outer facade (12), and the outer facade of the side arm (4) of the bracket (2) is the bracket side arm outer facade (13). The clamping block outer facade (12) and the bracket side arm outer facade (13) are both rectangular surfaces. The bracket side arm outer facade (13) extends toward its end to form an extended protruding plate (14). A clamping block limiting gap (15) is formed between the extended protruding plate (14) and the clamping block outer facade (12). The width of the clamping block limiting gap (15) is less than half of the length of the side of the clamping block outer surface (12) in the vertical direction. When the clamping jaw clamping block (3) swings up and down around the clamping jaw positioning axis (7), the clamping block outer surface (12) will contact the extended protruding plate (14). When the clamping block outer surface (12) touches the extended protruding plate (14), the clamping jaw clamping block (3) cannot continue to swing, thereby limiting the swing amplitude of the clamping jaw clamping block (3).

5. The chuck jaws for a three-jaw chuck of a machine tool according to claim 2, characterized in that: The bracket positioning shaft (6) is fixed to the inside of the top end of the clamping claw base (1) via a bracket screw (16) disposed therein, and the clamping claw positioning shaft (7) is fixed to the inside of the front end of the side arm (4) via a clamping claw screw (17) disposed therein.

6. The chuck jaws for a three-jaw chuck of a machine tool according to claim 2, characterized in that: The bracket positioning shaft (6) and the claw positioning shaft (7) are both stepped shafts, and a clamping platform (18) is provided at the top of the head portion thereof. The diameter of the clamping platform (18) is larger than the diameter of the shaft portion, and the clamping platform (18) is used to limit the axial displacement of the bracket (2) or the claw clamping block (3) on the bracket positioning shaft (6) or the claw positioning shaft (7), respectively.

7. The chuck jaws for a three-jaw chuck of a machine tool according to claim 1, characterized in that: A spring sheet (19) is fixedly arranged on the upper plane of the front end of the side arm (4) of the bracket (2), and the end of the spring sheet (19) is fixed to the upper plane of the front end of the side arm (4) by means of a screw. The front end of the spring sheet (19) extends to the upper plane of the claw clamping block (3) and fits with the upper plane of the claw clamping block (3), and the fitting position is located at the end of the claw clamping block (3). When the claw clamping block (3) is not in a clamping state, under the pressure of the spring sheet (19), the upper plane of the claw clamping block (3) is ensured to be parallel to the upper plane of the side arm (4) of the bracket (2).

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