CN109590767B

CN109590767B - Clamp with force measuring function

Info

Publication number: CN109590767B
Application number: CN201811425909.6A
Authority: CN
Inventors: 张定华; 刘冬生; 罗明; 胡媛
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2018-11-27
Filing date: 2018-11-27
Publication date: 2021-05-07
Anticipated expiration: 2038-11-27
Also published as: CN109590767A

Abstract

The invention discloses a clamp with a force measuring function, which is used for solving the technical problem of poor practicability of the existing clamp. The clamp comprises a base and a force measuring unit, wherein the force measuring unit consists of a V-shaped seat, a PVDF piezoelectric sheet and a V-shaped block, two V-shaped seat inclined planes and a mounting threaded hole are arranged on the V-shaped seat, two V-shaped block inclined planes are arranged on the left end face of the V-shaped block, the right end face of the V-shaped block is a cylindrical surface, and the cylindrical surface is in contact with the surface of a supported workpiece during force measurement. The V-shaped block and the V-shaped seat are connected into a whole and tightly press the PVDF piezoelectric sheet. And the base is provided with a groove and a wire groove which are matched with the force measuring unit, and the wire groove is used for leading out a wire of the PVDF piezoelectric sheet. The force measuring unit is arranged in interference fit with the groove on the base. The invention uses a plurality of clamps simultaneously, uniquely determines the magnitude and the direction of the cutting force acting on the workpiece through the synthesis of the force according to the position of each clamp in space and the magnitude and the direction of the measured force, and has good practicability.

Description

Clamp with force measuring function

Technical Field

The invention relates to a clamp, in particular to a clamp with a force measuring function.

Background

The document "Design, displacement and testing of a four-component milling gauge for the measurement of cutting force and torque, Mechanical Systems and Signal Processing, Vol21(3), p 1499-1511" discloses a force table with which the cutting force can be measured. The force measuring platform measures cutting force through an 8-angle strain ring supporting the platform surface of the force measuring platform, when the cutting force is measured, a workpiece is clamped on the platform surface of the force measuring platform, but limited by the size of the platform surface of the force measuring platform, and the force measuring platform can only clamp the workpiece smaller than the size of the platform surface of the force measuring platform. The large-scale integral structure spare size is great, and the structure is complicated, and rigidity change is big, and mostly is thin wall structure, can not install and carry out the cutting force measurement on the dynamometry platform. However, in the milling process, because the position of the clamping point is selected unreasonably or the cutting parameter is selected unreasonably, the workpiece is deformed greatly in the milling process, and the processing quality and efficiency are seriously affected. In order to improve the machining quality, the cutting force in the machining process needs to be measured for machining process control, clamping layout, machining parameters and the like.

Disclosure of Invention

In order to overcome the defect of poor practicability of the existing clamp, the invention provides a clamp with a force measuring function. The clamp comprises a base and a force measuring unit, wherein the force measuring unit consists of a V-shaped seat, a PVDF piezoelectric sheet and a V-shaped block, two V-shaped seat inclined planes and a mounting threaded hole are arranged on the V-shaped seat, two V-shaped block inclined planes are arranged on the left end face of the V-shaped block, the right end face of the V-shaped block is a cylindrical surface, and the cylindrical surface is in contact with the surface of a supported workpiece during force measurement. The screw is matched with the threaded hole through a countersunk head through hole in the V-shaped block, the V-shaped block and the V-shaped seat are connected into a whole, and the PVDF piezoelectric sheet is compressed. And the base is provided with a groove and a wire groove which are matched with the force measuring unit, and the wire groove is used for leading out a wire of the PVDF piezoelectric sheet. The force measuring unit is arranged in interference fit with the groove on the base. The invention uses a plurality of clamps simultaneously, uniquely determines the magnitude and the direction of the cutting force acting on the workpiece through the synthesis of the force according to the position of each clamp in space and the magnitude and the direction of the measured force, and has good practicability.

The technical scheme adopted by the invention for solving the technical problems is as follows: a clamp with a force measuring function is characterized by comprising a base 7 and a force measuring unit 1, wherein the force measuring unit 1 is composed of a V-shaped seat 5, PVDF

piezoelectric patches

3 and 4 and a V-shaped block 2, two V-shaped seat

inclined planes

501 and 502 and a threaded hole 503 are arranged on the V-shaped seat 5, and the V-shaped seat

inclined planes

501 and 502 are installed with one surfaces of the PVDF

piezoelectric patches

3 and 4 in a matched mode. The left end face of the V-shaped block 2 is provided with two V-shaped block

inclined planes

201 and 202, the V-shaped block

inclined planes

201 and 202 are installed with the other faces of the PVDF

piezoelectric sheets

3 and 4 in a matching mode, the right end face of the V-shaped block 2 is a cylindrical face, the cylindrical face is in contact with the surface of a supported workpiece during force measurement, and the V-shaped block 2 is provided with a through countersunk through hole 203. The screw 6 is matched with a threaded hole 503 on the V-shaped seat 5 through a countersunk head through hole 203 in the V-shaped block 2, so that the V-shaped block 2 and the V-shaped seat 5 are connected into a whole, and the PVDF

piezoelectric sheets

3 and 4 are pressed tightly. The base 7 is provided with a groove 701 and a wire groove 702 which are matched with the force measuring unit 1, and the wire groove 702 is used for leading out wires of the PVDF

piezoelectric sheets

3 and 4. The force measuring unit 1 is arranged in interference fit with the groove 701 on the base 7. The planes of the PVDF

piezoelectric sheets

3 and 4 are not parallel.

The invention has the beneficial effects that: the clamp comprises a base and a force measuring unit, wherein the force measuring unit consists of a V-shaped seat, a PVDF piezoelectric sheet and a V-shaped block, two V-shaped seat inclined planes and a mounting threaded hole are arranged on the V-shaped seat, two V-shaped block inclined planes are arranged on the left end face of the V-shaped block, the right end face of the V-shaped block is a cylindrical surface, and the cylindrical surface is in contact with the surface of a supported workpiece during force measurement. The screw is matched with the threaded hole through a countersunk head through hole in the V-shaped block, the V-shaped block and the V-shaped seat are connected into a whole, and the PVDF piezoelectric sheet is compressed. And the base is provided with a groove and a wire groove which are matched with the force measuring unit, and the wire groove is used for leading out a wire of the PVDF piezoelectric sheet. The force measuring unit is arranged in interference fit with the groove on the base. The invention uses a plurality of clamps simultaneously, uniquely determines the magnitude and the direction of the cutting force acting on the workpiece through the synthesis of the force according to the position of each clamp in space and the magnitude and the direction of the measured force, and has good practicability.

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Drawings

FIG. 1 is a schematic structural view of a clamp with force measurement function according to the present invention.

Fig. 2 is an exploded view of the assembly of fig. 1.

Fig. 3 is a schematic view of the structure in the other direction of fig. 1.

Fig. 4 is a sectional view a-a of fig. 3.

In the figure, 1-force measuring unit, 2-V-shaped block, 201, 202-V-shaped block inclined plane, 203-countersunk through hole, 3, 4-PVDF piezoelectric sheet, 5-V-shaped seat, 501, 502-V-shaped seat inclined plane, 503-threaded hole, 6-screw, 7-base, 701-groove and 702-wire guide groove.

Detailed Description

The following examples refer to FIGS. 1-4.

In the clamp with the force measuring function, OO is the central line of the whole clamp, and the force measuring unit 1 is arranged in the base 7 in an interference fit manner. The force measuring unit 1 comprises a V-shaped block 2, the right end face of the V-shaped block is a cylindrical surface which is in contact with the surface of a supported workpiece, and the left end face of the V-shaped block is two V-shaped block

inclined planes

201 and 202 which are in matched contact with PVDF

piezoelectric patches

3 and 4. The V-block 2 has a countersunk through hole 203 therethrough. And the V-shaped seat 5 is provided with two V-shaped seat

inclined surfaces

501 and 502 which are in fit contact with the PVDF

piezoelectric sheets

3 and 4 and a mounting threaded hole 503. The screw 6 is matched with the threaded hole 503 through a countersunk head through hole 203 in the V-shaped block 2, and the PVDF

piezoelectric sheets

3 and 4 are pressed tightly by connecting the V-shaped block 2 with the V-shaped seat 5. In order for the PVDF

piezoelectric sheets

3, 4 to operate in the linear range, a certain pre-load value needs to be applied to eliminate the non-linear contact gap, and this is achieved by tightening the screw 6 with a torque wrench.

The base 7 is provided with a groove 701 matched with the force measuring unit 1 and a wire groove 702 for leading out the PVDF

piezoelectric sheets

3 and 4.

ll is a plane perpendicular to the central line OO, the included angle formed by the PVDF piezoelectric sheet 3 and the ll plane is a, the included angle formed by the PVDF piezoelectric sheet 4 and the ll plane is b, the included angles a and b can be different in size, and the included angles a and b are preferably 30-45 degrees.

The planes of the PVDF

piezoelectric sheets

3 and 4 are not parallel, and the PVDF piezoelectric sheets are in a V-shaped position relation in space through the constraint action of the V-shaped block 2 and the V-shaped seat 5. The contact force acting on the cylindrical surface is transmitted to the PVDF

piezoelectric sheets

3 and 4 through the V-shaped block 2, the magnitude of the pressure applied to the PVDF

piezoelectric sheets

3 and 4 is in direct proportion to the output charge, and the direction is vertical to the plane where the PVDF

piezoelectric sheets

3 and 4 are located. According to the synthesis and the decomposition of the force, the magnitude and the direction of the force acting on the cylindrical surface are obtained.

The invention also provides a force measuring method.

Providing a plurality of (at least 3) clamps with force measuring functions;

the cylindrical surfaces of a plurality of clamps with force measuring functions are contacted with a supported structure, a certain contact pressure exists on the contact surfaces, and the clamps can measure the contact force change caused by cutting force.

According to the position of each clamp with the force measuring function in space and the magnitude and the direction of the measured force, the magnitude and the direction of the cutting force acting on the workpiece can be uniquely determined through force composition.

Claims

1. The utility model provides a take anchor clamps of dynamometry function which characterized in that: the PVDF piezoelectric force measuring device comprises a base (7) and a force measuring unit (1), wherein the force measuring unit (1) is composed of a V-shaped seat (5), PVDF piezoelectric sheets (3, 4) and a V-shaped block (2), two V-shaped seat inclined planes (501, 502) and a threaded hole (503) are arranged on the V-shaped seat (5), and the V-shaped seat inclined planes (501, 502) are installed on one surfaces of the PVDF piezoelectric sheets (3, 4) in a matching mode; the left end face of the V-shaped block (2) is provided with two V-shaped block inclined planes (201, 202), the V-shaped block inclined planes (201, 202) are installed with the other faces of the PVDF piezoelectric sheets (3, 4) in a matching mode, the right end face of the V-shaped block (2) is a cylindrical face, the cylindrical face is in contact with the surface of a supported workpiece during force measurement, and the V-shaped block (2) is provided with a through countersunk head through hole (203); the screw (6) is matched with a threaded hole (503) on the V-shaped seat (5) through a countersunk head through hole (203) in the V-shaped block (2), the V-shaped block (2) and the V-shaped seat (5) are connected into a whole, and the PVDF piezoelectric sheets (3, 4) are pressed tightly; a groove (701) and a lead groove (702) which are matched with the force measuring unit (1) are arranged on the base (7), and the lead groove (702) is used for leading out leads of the PVDF piezoelectric sheets (3, 4); the force measuring unit (1) is arranged in interference fit with the groove (701) on the base (7); the planes of the PVDF piezoelectric sheets (3, 4) are not parallel.