CN216731375U

CN216731375U - Split positioning fixture for lower crankcase

Info

Publication number: CN216731375U
Application number: CN202122586737.4U
Authority: CN
Inventors: 孙袁
Original assignee: Hangzhou Allied Precision Machinery Co ltd
Current assignee: Hangzhou Allied Precision Machinery Co ltd
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2022-06-14
Anticipated expiration: 2031-10-26

Abstract

The utility model discloses a split positioning fixture for a lower crankcase, and aims to overcome the defects of high cost and huge volume of an integral positioning tool. The utility model discloses an including the bottom plate, the tip locating plate, width setting element and length setting element, be equipped with the sliding tray on the tip locating plate, the sliding tray symmetry sets up, the width setting element includes the slider, the center-support piece, screw thread axle and both sides supporting shoe, the screw thread axle cartridge is on center-support piece and both sides supporting shoe, the screw thread axle is equipped with the screw thread section in the both sides of center-support piece, the direction of two screw thread sections is contrary mutually, two screw thread section difference threaded connection slider, the slider slides in the sliding tray, there is set screw on the slider, the length setting element includes U-shaped locating piece and adjustable support piece, be equipped with the slide opening on the adjustable support piece, cartridge and the flexible connection adjustable lever in the slide opening, the adjustable lever stretches out the adjustable locating piece of slip department fixedly connected with, the work piece outer fringe inserts in the U-shaped locating piece. The manufacturing cost of frock has been reduced to split type location frock.

Description

Split positioning fixture for lower crankcase

Technical Field

The utility model relates to the field of positioning tools, in particular to a split positioning fixture for a lower crankcase.

Background

As shown in fig. 1, for a lower crankcase with a long length and a heavy weight, the requirement on the machining precision of the product is high, and the requirement on the profile of the machined relative casting is also very high, which poses a challenge on whether the tool design can meet the positioning precision of the workpiece, and on the other hand, because the workpiece is very long, if the tool is designed to be a fully-enclosed tool, the tool is very large, and the cost is also very high.

Consequently, this application aims at designing a split type frock in order reduce cost under the prerequisite that satisfies work piece location requirement.

Disclosure of Invention

The utility model overcomes the defects of high cost and huge volume of an integral positioning tool, and provides the split positioning clamp for the lower crankcase, which can meet the positioning requirement of workpieces and reduce the manufacturing cost of the tool as much as possible.

In order to solve the technical problem, the utility model adopts the following technical scheme:

a split positioning clamp for a lower crankcase comprises a bottom plate, end positioning plates arranged at the positions, close to two ends, of the lower crankcase, a width positioning piece and a length positioning piece, wherein the width positioning piece and the length positioning piece are arranged on the end positioning plates, sliding grooves are formed in the end positioning plates and are arranged along the width direction, the sliding grooves are symmetrically arranged, the width positioning piece comprises a sliding block, a center supporting block, a threaded shaft and two side supporting blocks arranged at two ends of the end positioning plates, the threaded shaft is inserted in the center supporting block and the two side supporting blocks and is rotatably connected with the two side supporting blocks through a limiting shaft sleeve, threaded sections are arranged on two sides of the center supporting block by the threaded shaft, the directions of the two threaded sections are opposite, the two threaded sections are respectively in threaded connection with the sliding block, the sliding block slides in the sliding groove, a positioning screw is in threaded connection with the sliding block, the positioning screw abuts against the inner wall of the lower crankcase, the length positioning piece comprises a U-shaped positioning block arranged on one bottom plate and an adjustable supporting block arranged on the other bottom plate, the adjustable supporting blocks are provided with sliding holes, adjustable rods are inserted in the sliding holes, adjustable positioning blocks are fixedly connected at the positions, extending out of the sliding parts, of the adjustable rods, springs are arranged between the adjustable rods and the adjustable supporting blocks, the outer edges of the lower crankcase are inserted into the U-shaped positioning blocks, the springs outwards pull out the adjustable positioning blocks and drive the lower crankcase to move to the inner wall of the lower crankcase and meanwhile abut against the U-shaped positioning blocks and the adjustable positioning blocks, threaded shafts penetrate out the supporting blocks on the two sides from the same side of the lower crankcase, and the threaded shafts penetrating out of the supporting blocks on the two sides are in transmission connection and rotate synchronously through a transmission structure.

This application is fixed a position the work piece, mainly realizes the high accuracy location through the location of two sets of width directions and the both ends location of a set of length. The more far the two groups of positioning points in the width direction are arranged, the more accurate and reliable the workpiece positioning is, and the two pairs of positioning points can respectively and simultaneously find the inner cavity blank of the workpiece, so that the centers of the two ends of the workpiece are automatically aligned, the positioning error caused by the size deviation of the blank is eliminated, and the workpiece alignment efficiency is also improved.

The positioning in the width direction is specifically realized by: the central supporting block and the end positioning plate are used for positioning the threaded shaft and allowing the threaded shaft to rotate around the central supporting block and the end positioning plate relatively. The slide groove positions the slide block so that it can only move in the direction of the slide groove. The threaded shaft and the slider form a lead screw slider structure. Because the two screw shaft directions of the screw shaft are contrary, and the screw thread section is adapted to the corresponding slide block, when the screw shaft rotates, the two slide blocks can be close to or leave away from each other oppositely, the close or leave is synchronous, the two slide blocks are symmetrically arranged when the tool is assembled, the extending lengths of the positioning screws on the slide blocks are set to be the same, and the two positioning screws can be ensured to be abutted to a workpiece at the same time to complete positioning. After the two groups of width positioning pieces are positioned, the positioning in the width direction is completed.

The length direction positioning is realized by the following steps: the adjustable positioning block is pulled to drive the workpiece to move to abut against the U-shaped positioning block due to the elasticity of the spring, so that the positioning in the length direction is realized.

In positioning, positioning in the longitudinal direction is performed preferentially, and positioning in the width direction is performed again.

The transmission structure can be in various forms such as synchronous belt transmission, sprocket transmission, belt transmission and the like, and the arrangement mode is common knowledge in the field and is not described in detail herein. Through setting up synchronous rotation, simplified the operation for positioning speed improves production efficiency.

Preferably, the U-shaped positioning block is provided with a positioning screw which abuts against an outer edge of the lower crankcase from a longitudinal direction. After the positioning in the width direction is completed, the positioning screw is rotated to extend to abut against the lower crankcase, and the positioning in the length direction is locked.

Preferably, the adjustable supporting block is fixedly connected with a rotation inhibiting pin, the rotation inhibiting pin is parallel to the adjustable rod, the bottom of the adjustable positioning block is provided with a rotation inhibiting groove, and the rotation inhibiting pin is inserted into the rotation inhibiting groove to inhibit the rotation of the adjustable positioning block.

Preferably, a middle positioning plate is arranged between the end positioning plates, the distance between the middle positioning plate and the two end positioning plates is the same, side top supporting blocks are arranged on the two side supporting blocks and the middle positioning plate, supporting pieces which are vertically arranged are arranged on the side top supporting blocks, each supporting piece comprises a supporting pin fixedly connected to the arc-shaped molding and an auxiliary supporting nail with adjustable supporting height, and the supporting pieces support the bottom of the lower crankcase. The auxiliary supporting nail adjusts the supporting height thereof in a threaded mode, and is arranged on the same height plane with the supporting pin. Since the workpiece has an unavoidable deviation in the flatness of the bottom surface due to the accuracy, the support member may be suspended, resulting in the workpiece moving during machining. Therefore, the auxiliary supporting pins are arranged to be adjustable in supporting height, and the workpiece is better supported in the Z direction.

Preferably, the type of support on adjacent side roof support blocks is different. The end positioning plates, the middle positioning plates and the end positioning plates are arranged along the length direction, each positioning plate is provided with two supporting pieces in the width direction, the supporting pieces forming the 3X2 are arranged in an array mode, the supporting pins with unadjustable heights and the auxiliary supporting pins with adjustable heights are arranged in a staggered mode through the characteristics, the structure can better adapt to the flatness deviation of the bottom surface of a workpiece, the bottom surface of the workpiece is attached as far as possible, and the suspension phenomenon is reduced.

Preferably, a side roof screw is screwed to the side roof support block, and the side roof screw is provided in the width direction. The side top screws position the workpiece along the width direction, and the side top screws on two sides clamp the workpiece from outside to inside. The side top screw is matched with the width positioning piece to position the workpiece. The positioning heights of the side top screw and the width positioning piece are different, so that the workpiece is prevented from being overturned during machining. The supporting blocks at the two sides are fixedly connected with the supporting blocks at the side tops on the end positioning plate and used as supporting rib plates to improve the strength of the supporting rib plates.

Preferably, the side wall of the lower crankcase is provided with a plurality of windows, the side top supporting block is connected with a lower pressing block in a sliding mode along the width direction, the end portion of the lower pressing block is connected with a lower pressing screw in a threaded mode, and the lower pressing screw abuts against the lower edge of the windows and applies downward pressure to the lower crankcase. The downward pressure is generated by the downward pressing screw, and the workpiece is positioned in the Z direction by matching with the supporting piece. The lower pressing block is connected to the side top supporting block in a sliding mode, after the workpiece is positioned, the lower pressing block is pulled out towards the direction of the workpiece, then the lower pressing screw is adjusted to be pressed on the window in a pressing mode, and the position of the workpiece is locked. When the machining is finished, the lower pressing block is in the moving-out path of the workpiece, so that the lower pressing block is moved out firstly, then the workpiece is lifted, and the workpiece is separated from the positioning tool.

Preferably, the lower pressing block is provided with a waist groove, the side top supporting block is provided with a lower pressing positioning hole, a fastener is in threaded connection with the lower pressing positioning hole, and the fastener penetrates through the waist groove and presses the lower pressing block on the side top supporting block. The fasteners are fixed at different positions of the waist groove of the lower pressing block so as to adjust the positions of the opposite side top supporting blocks of the lower pressing block.

Preferably, the two supporting members on the middle positioning plate are arranged at two ends of the diagonal position of the middle positioning plate. The triangle formed by the connecting line of each supporting pin is the same as the triangle formed by the auxiliary supporting pin. The structure ensures that the triangle has a long side and a short side, so that the bottom surface of the workpiece can be better supported and is prevented from being suspended.

Preferably, the supporting piece is fixedly connected to the supporting sliding block, a vertical supporting sliding groove is formed in the side top supporting block, the supporting sliding block is connected to the supporting sliding groove in a sliding mode, a spring is arranged at the bottom of the supporting sliding block, the lower pressing block is hinged to a connecting rod, the connecting rod is hinged to the lower pressing block, a first matching groove is formed in the side top supporting block and comprises a vertically-arranged short groove and a horizontally-arranged long groove, a second matching groove is formed in the lower pressing block in an inclined mode, a hinge joint is connected to the root portion of the lower pressing screw in a threaded mode, and the hinge joint is connected with the first matching groove and the second matching groove in a hinged mode.

When the supporting piece is pressed by the workpiece, the force is transmitted to the supporting sliding block. The support slider compresses the spring and moves downward. The connecting rod on the supporting slide block drives the lower pressing block to slide relative to the side top supporting block, and the lower pressing block slides towards the workpiece. The first matching groove on the side top supporting block and the second matching groove of the lower pressing block drive the lower pressing screw to move under the movement of the lower pressing block. The movement track of the pressing screw is that the pressing screw moves towards the workpiece along the long groove, when the pressing screw moves to the end part of the long groove, the pressing screw moves to a position to be pressed, the pressing block continues to move, and the pressing screw moves downwards along the short groove. The extension length of the pressing screw is adjustable. The extension of the down-pressure screw is adjusted to abut against the workpiece.

When the workpiece is machined and leaves the tool, the extension amount of the pressing screw is retracted, so that a gap is formed between the pressing screw and the workpiece. The workpiece is lifted, the spring is reset, the support sliding block is reset, the lower pressing block retracts under the action of the connecting rod, the hinged joint moves upwards along the short groove, the hinged joint moves along the long groove when reaching the highest position of the short groove, and meanwhile the lower pressing block exits from the motion path of the workpiece.

Compared with the mode of adjusting the position of the lower pressing block by the fastener, the mode does not need to screw screws to adjust one by one, is more convenient, and has the advantage of saving manpower.

Compared with the prior art, the utility model has the beneficial effects that: (1) the manufacturing cost of the tool is reduced by the aid of the split type positioning tool; (2) the two ends of the workpiece in the length direction are positioned, and the long workpiece is well positioned.

Drawings

FIG. 1 is a perspective view of a workpiece according to the present invention;

FIG. 2 is a perspective view of the tooling of the present invention;

FIG. 3 is an enlarged view at A in FIG. 2;

FIG. 4 is an enlarged view at A in FIG. 3;

FIG. 5 is a schematic view of a threaded shaft of the present invention

FIG. 6 is a cross-sectional view of the tooling of the present invention;

FIG. 7 is a schematic view of example 2;

in the figure:

the device comprises a workpiece 1, a bottom plate 2, an end positioning plate 3, a middle positioning plate 4, a slider 5, a center supporting block 6, two side supporting blocks 7, a threaded shaft 8, a threaded section 9, a positioning screw 10, an adjustable supporting block 11, a sliding hole 12, an adjustable rod 13, a spring 14, an adjustable positioning block 15, a rotation inhibiting pin 16, a rotation inhibiting groove 17, a U-shaped positioning block 18, a side top supporting block 19, a supporting piece 20, a supporting pin 21, an auxiliary supporting nail 22, a side top screw 23, a window 24, a lower pressing block 25, a waist groove 26, a lower pressing screw 27, a supporting slider 28, a supporting sliding groove 29, a connecting rod 30, a first matching groove 31, a short groove 32, a long groove 33, a second matching groove 34 and a hinge joint 35.

Detailed Description

The present disclosure is further described with reference to the following drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only relational terms determined for convenience in describing structural relationships of the parts or elements of the present disclosure, and do not refer to any parts or elements of the present disclosure, and are not to be construed as limiting the present disclosure.

In the present disclosure, terms such as "fixedly connected," "connected," and the like should be understood broadly, and mean that they may be fixedly connected, integrally connected, or detachably connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present disclosure can be determined on a case-by-case basis by persons skilled in the relevant art or technicians, and are not to be construed as limitations of the present disclosure.

Example 1:

a split positioning fixture for a lower crankcase is shown in figures 2 to 4 and comprises a bottom plate 2, end positioning plates 3 arranged at the positions, close to two ends, of the lower crankcase, a width positioning piece and a length positioning piece, wherein the width positioning piece and the length positioning piece are arranged on the end positioning plates 3.

The end positioning plate 3 is provided with a sliding groove arranged along the width direction, the sliding groove is symmetrically arranged, the width positioning piece comprises a sliding block 5, a central supporting block 6, a threaded shaft 8 and two side supporting blocks 7 arranged at two ends of the end positioning plate 3, the threaded shaft 8 is inserted into the central supporting block 6 and the two side supporting blocks 7, and the threaded shaft 8 is rotatably connected with the two side supporting blocks 7 through a limiting shaft sleeve. As shown in fig. 5, the threaded shaft 8 is provided with threaded sections 9 on both sides of the center support block 6, the directions of the two threaded sections 9 are opposite, the two threaded sections 9 are respectively in threaded connection with the sliding block 5, the sliding block 5 slides in the sliding groove, the sliding block 5 is in threaded connection with a positioning screw 10, and the positioning screw 10 abuts against the inner wall of the lower crankcase. The threaded shaft 8 penetrates out of the supporting blocks 7 on the two sides from the same side of the lower crankcase, and the threaded shaft 8 penetrating out of the supporting blocks 7 on the two sides is in transmission connection through the transmission structure and rotates synchronously. The transmission structure can be in various forms such as synchronous belt transmission, sprocket transmission, belt transmission and the like, and the arrangement mode is common knowledge in the field and is not described in detail herein. Through setting up its synchronous rotation, simplified the operation for positioning speed improves production efficiency.

As shown in fig. 4 and 6, the length positioning element includes a U-shaped positioning block 18 disposed on one base plate 2 and an adjustable supporting block 11 disposed on the other base plate 2, a sliding hole 12 is disposed on the adjustable supporting block 11, an adjustable rod 13 is inserted into the sliding hole 12, and an adjustable positioning block 15 is fixedly connected to a sliding position where the adjustable rod 13 extends. Fixedly connected with rotation suppression round pin 16 on the adjustable supporting shoe 11, rotation suppression round pin 16 is parallel with adjustable rod 13, and the bottom of adjustable locating piece 15 is equipped with rotation suppression groove 17, and rotation suppression round pin 16 inserts and rotates in suppression groove 17 in order to prevent the rotation of adjustable locating piece 15. A spring 14 is arranged between the adjustable rod 13 and the adjustable supporting block 11, the outer edge of the lower crankcase is inserted into the U-shaped positioning block 18, the spring 14 pulls out the adjustable positioning block 15 outwards and drives the lower crankcase to move to the inner wall of the lower crankcase and abut against the U-shaped positioning block 18 and the adjustable positioning block 15 at the same time. The U-shaped positioning block 18 is provided with a positioning screw 10, and the positioning screw 10 is abutted against the outer edge of the lower crankcase from the length direction. After the positioning in the width direction is completed, the positioning screw 10 is rotated to extend to abut against the lower crankcase, and the positioning in the length direction is locked.

This application fixes a position work piece 1, mainly realizes the high accuracy location through the location of two sets of width directions and the both ends location of a set of length. The farther the two groups of positioning points in the width direction are arranged, the more accurate and reliable the positioning of the workpiece 1 is, and the two pairs of positioning points can respectively and simultaneously find the inner cavity blank of the workpiece 1, so that the centers of the two ends of the workpiece 1 are automatically aligned, the positioning error caused by the size deviation of the blank is eliminated, and the alignment efficiency of the workpiece 1 is also improved.

The positioning in the width direction is realized in particular by: the center supporting block 6 and the end positioning plate 3 are used for positioning the threaded shaft 8, and the threaded shaft 8 rotates around the center supporting block 6 and the end positioning plate 3 relatively. The slide groove positions the slide 5 such that it can only move in the direction of the slide groove. The threaded shaft 8 and the slider 5 form a lead screw slider 5 structure. Because 8 directions of two screw shafts of screw shaft 8 are contrary mutually, and its screw thread section 9 suits with corresponding slider 5, when screw shaft 8 rotated, two sliders 5 can be close to or leave mutually back of the body mutually, and this kind is close to or leaves synchronously, sets up two slider 5 symmetries when the equipment frock and sets up the extension length of set screw 10 on the slider 5 to be the same, just can guarantee that two set screw 10 butt work piece 1 simultaneously, accomplish the location. After the two groups of width positioning pieces are positioned, the positioning in the width direction is completed.

The length direction positioning is realized by the following steps: the workpiece 1 is inserted into an opening of the U-shaped positioning block 18, the adjustable rod 13 is pushed, the distance between the adjustable positioning block 15 and the adjustable supporting block 11 is increased, the workpiece 1 is inserted, and due to the elastic force of the spring 14, the adjustable positioning block 15 is pulled to drive the workpiece 1 to move to abut against the U-shaped positioning block 18, so that the positioning in the length direction is realized.

Be equipped with middle part locating plate 4 between the tip locating plate 3, middle part locating plate 4 is the same in the interval between both ends locating plate 3, all is equipped with side top supporting block 19 on both sides supporting shoe 7 and the middle part locating plate 4, is equipped with the support piece 20 of vertical setting on the side top supporting block 19, and support piece 20 includes the supporting pin 21 of fixed connection on the arc molding and supports height-adjustable's supplementary supporting nail 22, and support piece 20 supports the bottom of crankcase down. The auxiliary supporting nail 22 adjusts the supporting height thereof in a threaded manner, and the auxiliary supporting nail 22 is arranged on the same height plane with the supporting pin 21. Since the workpiece 1 inevitably deviates in the flatness of the bottom surface due to the accuracy, the support 20 may be suspended, resulting in the workpiece 1 moving during machining. For this purpose, auxiliary support pins 22 are provided to support the workpiece 1 in an adjustable height, preferably in the Z-direction. The kind of the support member 20 on the adjacent side roof support blocks 19 is different. The end positioning plates 3, the middle positioning plates 4 and the end positioning plates 3 are arranged along the length direction, each positioning plate is provided with two supporting pieces 20 in the width direction, the supporting pieces 20 of the 3X2 are arranged in an array mode, the height-adjustable supporting pins 21 and the height-adjustable auxiliary supporting pins 22 are arranged in a staggered mode due to the characteristics, the structure can be better adapted to the flatness deviation of the bottom surface of the workpiece 1, the bottom surface of the workpiece 1 can be attached as far as possible, and the suspension phenomenon is reduced. The two support members 20 of the middle positioning plate 4 are disposed at both ends of the diagonal position of the middle positioning plate 4. The triangle formed by connecting the respective support pins 21 is the same as the triangle formed by the auxiliary support pins 22. The structure enables the triangle to be provided with a long side and a short side, so that the bottom surface of the workpiece 1 can be better supported and is prevented from being suspended.

A side roof screw 23 is screwed to the side roof support block 19, and the side roof screw 23 is provided in the width direction. The side top screws 23 position the workpiece 1 in the width direction, and the side top screws 23 on both sides clamp the workpiece 1 from outside to inside. The side top screw 23 is matched with the width positioning piece to position the workpiece 1. The side top screw 23 and the width positioning piece are positioned at different heights to prevent the workpiece 1 from turning over during machining. The side wall of the lower crankcase is provided with a plurality of windows 24, the side top supporting block 19 is connected with a lower pressing block 25 in a sliding mode along the width direction, the end portion of the lower pressing block 25 is connected with a lower pressing screw 27 in a threaded mode, and the lower pressing screw 27 abuts against the lower edge of the windows 24 and applies downward pressure to the lower crankcase. The pressing screw 27 generates downward pressure to cooperate with the supporting member 20 to perform Z-direction positioning of the workpiece 1. The lower pressing block 25 is connected to the side top supporting block 19 in a sliding mode, after the workpiece 1 is located, the lower pressing block 25 is pulled out towards the workpiece 1, then the lower pressing screw 27 is adjusted to be pressed on the window 24, and the position of the workpiece 1 is locked. When the machining is finished, because the lower pressing block 25 is in the moving-out path of the workpiece 1, the lower pressing block 25 is moved out first, and then the workpiece 1 is lifted and separated from the positioning tool.

The lower pressing block 25 is provided with a waist groove 26, the side top supporting block 19 is provided with a lower pressing positioning hole, a fastener is connected to the lower pressing positioning hole through threads, and the fastener penetrates through the waist groove 26 and presses the lower pressing block 25 on the side top supporting block 19. The fasteners are fixed at different positions of the waist groove 26 of the lower pressing block 25 so as to adjust the positions of the opposite side top supporting blocks 19 of the lower pressing block 25.

Example 2:

in this embodiment, the connection mode of the lower pressing block 25 is different from that of embodiment 1, specifically:

as shown in fig. 7, the supporting member 20 is fixedly connected to the supporting sliding block 28, a vertical supporting sliding groove 29 is arranged on the side top supporting block 19, the supporting sliding block 28 is slidably connected to the supporting sliding groove 29, a spring 14 is arranged at the bottom of the supporting sliding block 28, the lower pressing block 25 is hinged to a connecting rod 30, the connecting rod 30 is hinged to the lower pressing block 25, a first matching groove 31 is arranged on the side top supporting block 19, the first matching groove 31 includes a vertically arranged short groove 32 and a horizontally arranged long groove 33, a second matching groove 34 is arranged on the lower pressing block 25 in an inclined manner, a hinge joint 35 is in threaded connection with the root of the lower pressing screw 27, and the hinge joint 35 is in hinged connection with the first matching groove 31 and the second matching groove 34.

When the support 20 is subjected to the pressure of the workpiece 1, the force is transmitted to the support slider 28. The support slider 5 compresses the spring 14 and moves downward. The connecting rod 30 on the supporting slide block 5 drives the lower pressing block 25 to slide relative to the side top supporting block 19, and the lower pressing block 25 slides towards the workpiece 1. The first matching groove 31 on the side top supporting block 19 and the second matching groove 34 of the lower pressing block 25 drive the lower pressing screw 27 to move under the movement of the lower pressing block 25. The movement track of the pressing screw 27 is to move towards the workpiece 1 along the long groove 33, when the pressing screw moves to the end of the long groove 33, the pressing screw moves to the position to be pressed, the pressing block 25 continues to move, and the pressing screw 27 moves downwards along the short groove 32. The extension length of the down-pressure screw 27 is adjustable. The projecting amount of the down-pressure screw 27 is adjusted to abut the workpiece 1.

When the workpiece 1 is finished and leaves the tool, the protruding amount of the pressing screw 27 is retracted, so that a gap is formed between the pressing screw 27 and the workpiece 1. The workpiece 1 is lifted, the spring 14 is reset, the support slide block 28 is reset, the lower pressing block 25 retracts under the action of the connecting rod 30, the hinge joint 35 moves upwards along the short groove 32, the hinge joint 35 moves along the long groove 33 when reaching the highest position of the short groove 32, and meanwhile the lower pressing block 25 exits from the moving path of the workpiece 1.

Compared with the mode of adjusting the position of the lower pressing block 25 by adopting a fastener, the mode does not need to screw screws to adjust one by one, is more convenient and has the advantage of saving manpower.

The above-described embodiments are merely preferred embodiments of the present invention, which is not intended to be limiting in any way, and other variations and modifications are possible without departing from the scope of the utility model as set forth in the appended claims.

Claims

1. A split positioning fixture for a lower crankcase is characterized by comprising a bottom plate, end positioning plates arranged at the positions, close to two ends, of the lower crankcase, a width positioning piece and a length positioning piece, wherein the end positioning plates are arranged on the end positioning plates, the width positioning piece and the length positioning piece are arranged on the end positioning plates, sliding grooves are formed in the end positioning plates in the width direction and are symmetrically arranged, the width positioning piece comprises sliding blocks, a center supporting block, a threaded shaft and two side supporting blocks arranged at two ends of the end positioning plates, the threaded shaft is inserted in the center supporting block and the two side supporting blocks, the threaded shaft is rotatably connected with the two side supporting blocks through a limiting shaft sleeve, threaded sections are arranged on two sides of the center supporting block of the threaded shaft, the directions of the two threaded sections are opposite, the two threaded sections are respectively in threaded connection with the sliding blocks, the sliding blocks slide in the sliding grooves, positioning screws are in threaded connection with the inner walls of the lower crankcase and abut against the inner walls of the lower crankcase, and the threaded shafts penetrate out the two side supporting blocks from the same side of the lower crankcase, the threaded shafts penetrating through the supporting blocks on the two sides are in transmission connection through a transmission structure and synchronously rotate, the length positioning piece comprises a U-shaped positioning block arranged on one base plate and an adjustable supporting block arranged on the other base plate, a sliding hole is formed in the adjustable supporting block, an adjustable rod is inserted into the sliding hole, the position, extending out of the sliding part, of the adjustable rod is fixedly connected with the adjustable positioning block, a spring is arranged between the adjustable rod and the adjustable supporting block, the outer edge of the lower crankcase is inserted into the U-shaped positioning block, and the spring pulls out the adjustable positioning block and drives the lower crankcase to move to the inner wall of the lower crankcase and abut against the U-shaped positioning block and the adjustable positioning block at the same time.

2. The split positioning fixture for the lower crankcase according to claim 1, wherein a positioning screw is provided on the U-shaped positioning block, and the positioning screw abuts against an outer edge of the lower crankcase in a length direction.

3. The split positioning fixture of claim 1, wherein a rotation inhibiting pin is fixedly connected to the adjustable support block, the rotation inhibiting pin is parallel to the adjustable rod, a rotation inhibiting groove is formed in a bottom of the adjustable positioning block, and the rotation inhibiting pin is inserted into the rotation inhibiting groove to inhibit rotation of the adjustable positioning block.

4. The split positioning fixture for the lower crankcase according to claim 1, wherein a middle positioning plate is disposed between the end positioning plates, the middle positioning plate has the same distance between the end positioning plates, the two side supporting blocks and the middle positioning plate are both provided with side top supporting blocks, the side top supporting blocks are provided with vertically disposed supporting members, the supporting members comprise supporting pins fixedly connected to the arc-shaped molds and auxiliary supporting pins with adjustable supporting heights, and the supporting members support the bottom of the lower crankcase.

5. The split positioning fixture for the lower crankcase according to claim 4, wherein a side top screw is screwed on the side top supporting block and arranged along the width direction.

6. The split positioning fixture of claim 4, wherein the side wall of the lower crankcase is provided with a plurality of windows, the top side supporting blocks are connected with lower pressing blocks in a sliding mode along the width direction, the end portions of the lower pressing blocks are connected with lower pressing screws in a threaded mode, and the lower pressing screws abut against the lower edge of the windows and apply downward pressure to the lower crankcase.

7. The split positioning fixture for the lower crankcase as claimed in claim 5, wherein the lower pressing block is provided with a waist slot, the side top supporting block is provided with a lower pressing positioning hole, a fastening member is screwed in the lower pressing positioning hole, and the fastening member passes through the waist slot and presses the lower pressing block onto the side top supporting block.

8. The split positioning fixture for the lower crankcase according to any one of claims 4 to 7, wherein the two supporting members on the middle positioning plate are arranged at two ends of the diagonal position of the middle positioning plate.