CN220388743U

CN220388743U - Machining clamp for main bearing caps of engine cylinder blocks

Info

Publication number: CN220388743U
Application number: CN202322252437.1U
Authority: CN
Inventors: 周杨波; 吴浩; 甘启山
Original assignee: Wuhan Hongboxin Technology Co ltd
Current assignee: Wuhan Hongboxin Technology Co ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2024-01-26
Anticipated expiration: 2033-08-22

Abstract

The utility model provides a machining fixture for a main bearing cover of an engine cylinder body, which comprises a bottom frame, a plurality of bottom frame middle ribs and a plurality of mounting holes, wherein the bottom frame middle ribs comprise a circular arch and two support legs, the circular arch is positioned between the two support legs, the machining fixture comprises a bottom plate, a positioning component and a pressing component, at least two positioning pieces of the positioning component are respectively inserted into the corresponding at least two mounting holes and support the surface of the bottom frame far away from the bottom frame middle ribs, the main bearing cover is positioned and supported, circumferential rotation is limited, a pressing plate of the pressing component is rotatably connected with a pressing seat and can move in the vertical direction, the pressing plate is rotated to be perpendicular to the bottom frame middle ribs, two ends of the pressing plate respectively press against one circular arch, displacement in the vertical direction is limited, the main bearing cover can be effectively prevented from moving in the machining process through limiting the circumferential direction and the vertical direction, the positioning standard of the main bearing cover cannot be changed, the defect of machining size is avoided, and the machining precision is improved.

Description

Machining clamp for main bearing caps of engine cylinder blocks

Technical Field

The utility model relates to the technical field of machining clamps, in particular to a machining clamp for a main bearing cap of an engine cylinder body.

Background

The main bearing cap of an automobile engine is one of the important parts of an automobile as a part of an engine room assembly. In order to facilitate manufacturing, the conventional main bearing caps are only arranged according to the shape of the main bearing, so long as the installation and protection of the engine gear can be satisfied, and the structural layout is generally complex. In addition, the main bearing cap of the engine is clamped manually in the process of milling and punching, the main bearing cap of the engine is damaged in the clamping process, the operation is complex and difficult, and the processing efficiency is low; if the clamping is not tight, the machining precision of the main bearing cover of the engine can be affected.

In view of the above, the utility model patent with publication number CN 204976122U discloses a clamp for a main bearing cap of an engine, which comprises a fixing part, the fixing part comprises a base, a supporting plate, a positioning reference plate and a positioning plate, the supporting plate, the positioning reference plate and the positioning plate are fixedly installed on the base, and further comprises a pneumatic part, the pneumatic part comprises a cylinder, an installation seat, a bolt, a hinged support and a clamping rod, the cylinder and the hinged support are fixed on the installation seat, the installation seat is fixed on the base, one end of the clamping rod is fixed on a hydraulic rod of the cylinder through the bolt, the middle part of the clamping rod is fixed on the hinged support through the bolt, and the clamping end of the clamping rod is arranged above the positioning plate. The main bearing cover of the engine is clamped by the cylinder control clamping rod, and only the upper part of the main bearing cover of the engine is clamped and fixed, and as the side surface and the bottom are not limited, the main bearing cover is easy to move in the machining process, so that the positioning standard of the main bearing cover is changed, and the machining size is poor.

Disclosure of Invention

In view of the above, the present utility model provides a machining fixture for a main bearing cap of an engine cylinder block, so as to solve the problem that the main bearing cap provided in the above background art is easy to move, and the positioning reference of the main bearing cap is changed, so that the machining size is poor and the accuracy requirement cannot be met.

The technical scheme of the utility model is realized as follows:

the utility model provides a machining fixture for a main bearing cover of an engine cylinder body, which comprises a bottom frame, a plurality of bottom frame middle ribs connected with the bottom frame, and a plurality of mounting holes penetrating through the bottom frame and the bottom frame middle ribs, the middle rib of underframe includes dome and two stabilizer blades, the dome is located two between the stabilizer blade, engine block main bearing cap's machining anchor clamps include the bottom plate, and install in locating component and the hold-down assembly on the bottom plate, wherein:

the positioning assembly comprises at least two positioning pieces, wherein the at least two positioning pieces are respectively and partially inserted into the corresponding at least two mounting holes and support the surface of the bottom frame away from the middle rib of the bottom frame;

the pressing assembly comprises at least one pressing piece, the pressing piece comprises a pressing seat and a pressing plate, the pressing seat is arranged on the bottom plate, the pressing plate is rotatably connected with the pressing seat and can move along the vertical direction, and when the pressing plate rotates to be perpendicular to the middle rib of the bottom frame, the pressing plate descends to the two ends of the pressing plate to respectively support against one arch.

On the basis of the technical scheme, preferably, the pressing piece further comprises a hydraulic rod, the hydraulic rod is vertically arranged in the pressing seat, the hydraulic rod can be lifted and rotated, and the pressing plate is connected with the hydraulic rod.

On the basis of the technical scheme, preferably, the pressing plate comprises a connecting plate and two pressing parts, the connecting plate is connected with the hydraulic rod, the two pressing parts are respectively connected with two ends of the connecting plate, the pressing parts are provided with circular arc pressing surfaces, and the circular arc pressing surfaces are used for pressing the inner wall of the circular arch.

On the basis of the technical scheme, preferably, the positioning piece comprises a positioning seat and a positioning pin, the positioning seat is arranged on the bottom plate, the positioning pin is arranged at the top of the positioning seat, the positioning pin is inserted into the mounting hole, and the top of the positioning seat is abutted to the surface, away from the middle rib of the bottom frame, of the bottom frame.

On the basis of the technical scheme, preferably, the top of the positioning pin is provided with an arc guide surface.

On the basis of the technical scheme, preferably, the two positioning pieces are respectively matched with the mounting holes in the middle ribs of the bottom frames at the two ends.

On the basis of the technical scheme, preferably, the bottom frame middle ribs at least comprise three, the machining fixture further comprises a supporting component arranged on the bottom plate, the supporting component comprises at least two main supporting pieces, and the two main supporting pieces are supported at positions of the bottom frame middle ribs in the middle of the corresponding positions of the bottom frame.

On the basis of the above technical scheme, preferably, the support assembly further comprises two auxiliary support pieces, the two auxiliary support pieces are respectively supported at the bottom of the bottom frame, the two auxiliary support pieces are respectively located below the middle ribs of the same bottom frame with the two positioning pieces, the top of the two auxiliary support pieces is provided with an air detection hole, and the air detection hole is used for detecting whether the bottom of the bottom frame is completely attached to the top of the auxiliary support piece.

On the basis of the technical scheme, the main bearing cap is preferably provided with a water gun arranged on the side surface of the bottom plate and an air tap above the bottom plate, wherein the water gun is used for spraying water to the main bearing cap; the outlet of the air tap faces the positioning piece, the main support piece and the auxiliary support piece and is used for spraying air to clean the support surface of the top.

On the basis of the technical scheme, the base is preferably further arranged on a machining workbench in a sliding mode, and the bottom plate is arranged on the base.

The machining fixture for the main bearing cover of the engine cylinder body has the following advantages compared with the prior art

The beneficial effects are that:

(1) The positioning pieces are respectively and partially inserted into the corresponding at least two mounting holes and support the surface of the bottom frame away from the middle rib of the bottom frame, so that the main bearing cover is positioned and supported, the circumferential rotation of the main bearing cover is limited, the pressing plate is rotatably connected with the pressing seat and can move along the vertical direction, when the pressing plate rotates to be vertical to the middle rib of the bottom frame, the two ends of the pressing plate are respectively pressed against one circular arch to press the main bearing cover, the displacement of the main bearing cover in the vertical direction is limited, the main bearing cover can be effectively prevented from moving in the machining process through limiting the circumferential direction and the vertical direction, the positioning reference of the main bearing cover is not changed, the defect of machining size is avoided, and the machining precision is improved;

(2) The pressing plate comprises a connecting plate and two pressing parts, the two pressing parts respectively press the two circular arches, the pressing parts are provided with circular arc pressing surfaces, the circular arc pressing surfaces are used for pressing the inner walls of the circular arches, and compared with the point contact or plane contact with the inner walls of the circular arches, the circular arc pressing surfaces can not damage the inner walls of the circular arches, so that the quality of products can be improved;

(3) The positioning pin is arranged at the top of the positioning seat, the positioning pin is inserted into the mounting hole, positioning of the main bearing cover is achieved, the top of the positioning seat is abutted against the surface, far away from the middle rib of the bottom frame, supporting of the main bearing cover is achieved, positioning of the main bearing cover is achieved through the positioning piece, supporting of the main bearing cover is achieved, compared with the positioning and supporting of the main bearing cover, the positioning pin is arranged at different positions, the number of parts is saved, occupied space is reduced, and flexible layout is facilitated;

(4) Through the top of locating pin is provided with the circular arc guide surface, and the mounting hole cover of being convenient for is in on the locating pin, compare in the structure of top and side right angle transition, the circular arc guide surface can not cause the damage to the inner wall of mounting hole.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a perspective view of an engine block main bearing cap of the present utility model in a mounted condition with a machining fixture;

FIG. 2 is a perspective view of a machining fixture for a main bearing cap of an engine block according to the present utility model;

FIG. 3 is a perspective view of the main bearing cap of the present utility model;

FIG. 4 is a perspective view of a positioning member of the present utility model;

fig. 5 is an exploded view of the compression member of the present utility model.

The reference numerals in the above figures are respectively: 100 parts of main bearing caps, 110 parts of bottom frames, 120 parts of bottom frame middle ribs, 121 parts of supporting legs, 122 parts of circular arches and 130 parts of mounting holes; 200-working table; 1-a bottom plate; 2-positioning components, 21-positioning pieces, 210-positioning seats, 220-positioning pins and 221-arc guide surfaces; 3-compressing components, 31-compressing pieces, 310-compressing seats, 320-compressing plates, 321-connecting plates, 322-compressing parts, 3221-circular arc compressing surfaces and 330-hydraulic rods; 4-supporting components, 41-main supporting pieces, 42-auxiliary supporting pieces and 421-air detection holes; 5-a water spraying gun; 6-an air tap; 7-a base; 8-four-axis assembly; 9-tool apron pairs.

Detailed Description

The following description of the embodiments of the present utility model will clearly and fully describe the technical aspects of the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, are intended to fall within the scope of the present utility model.

Referring to fig. 1-5, an embodiment of the present utility model provides a machining fixture for a main bearing cap of an engine block, the main bearing cap 100 including a bottom frame 110 and a plurality of bottom frame middle ribs 120 connected to the bottom frame 110, and a plurality of mounting holes 130 penetrating the bottom frame 110 and the bottom frame middle ribs 120, the bottom frame middle ribs 120 including a dome 122 and two legs 121, the dome 122 being located between the two legs 121, the machining fixture for the main bearing cap of the engine block including a bottom plate 1, and a positioning assembly 2 and a pressing assembly 3 mounted on the bottom plate 1, wherein:

the positioning assembly 2 comprises at least two positioning pieces 21, wherein the at least two positioning pieces 21 are respectively and partially inserted into the corresponding at least two mounting holes 130 and support the surface of the bottom frame 110 away from the bottom frame middle rib 120;

the pressing assembly 3 comprises at least one pressing member 31, the pressing member 31 comprises a pressing seat 310 and a pressing plate 320, the pressing seat 310 is mounted on the bottom plate 1, the pressing plate 320 is rotatably connected with the pressing seat 310, the pressing plate 320 can move along the vertical direction, and when the pressing plate 320 rotates to be perpendicular to the bottom frame middle rib 120, the pressing plate 320 descends to the position that two ends of the pressing plate 320 respectively press against one circular arch 122.

According to the machining fixture for the main bearing cap of the engine cylinder block, provided by the embodiment of the utility model, the main bearing cap 100 is positioned and supported by the surfaces of the at least two positioning pieces 21, which are respectively partially inserted into the corresponding at least two mounting holes 130 and support the bottom frame 110 away from the bottom frame middle rib 120, so that the circumferential rotation of the main bearing cap 100 is limited, the pressing plate 320 is rotatably connected with the pressing seat 310 and can move in the vertical direction, when the pressing plate 320 rotates to be vertical to the bottom frame middle rib 120, the two ends of the pressing plate 320 respectively press against one circular arch 122 to press the main bearing cap 100, the displacement of the main bearing cap 100 in the vertical direction is limited, the main bearing cap 100 can be effectively prevented from moving in the machining process by limiting the circumferential direction and the vertical direction, the positioning standard of the main bearing cap 100 is not changed, the poor machining size is avoided, and the machining precision is improved.

In some embodiments, the pressing member 31 further includes a hydraulic rod 330, the hydraulic rod 330 is vertically disposed in the pressing seat 310, the hydraulic rod 330 is capable of being lifted and rotated, and the pressing plate 320 is connected with the hydraulic rod 330. The hydraulic rod 330 is arranged in the compression seat 310, the hydraulic rod 330 can lift and rotate to drive the pressing plate 320 to lift and rotate, when the main bearing cap 100 is placed in, the pressing plate 320 is rotated to be parallel to the middle ribs 120 of the bottom frame, after the main bearing cap 100 is placed in, the hydraulic rod 330 is lifted and rotated to enable the pressing plate 320 to be rotated to be perpendicular to the middle ribs 120 of the bottom frame, and then the hydraulic rod 330 is lowered to enable two ends of the pressing plate 320 to respectively support against one circular arch 122, so that the main bearing cap 100 is compressed.

In some embodiments, the pressing plate 320 includes a connecting plate 321 and two pressing portions 322, the connecting plate 321 is connected to the hydraulic rod 330, the two pressing portions 322 are respectively connected to two ends of the connecting plate 321, the pressing portions 322 are provided with an arc pressing surface 3221, and the arc pressing surface 3221 is used for pressing against the inner wall of the dome 122. The pressing plate 320 comprises a connecting plate 321 and two pressing parts 322, the two pressing parts 322 respectively press the two circular arches 122, the pressing parts 322 are provided with arc pressing surfaces 3221, the arc pressing surfaces 3221 are used for pressing the inner walls of the circular arches 122, and compared with the point contact or plane contact with the inner walls of the circular arches 122, the arc pressing surfaces 3221 cannot damage the inner walls of the circular arches 122, so that the quality of products can be improved.

In some embodiments, the positioning member 21 includes a positioning seat 210 and a positioning pin 220, the positioning seat 210 is mounted on the base plate 1, the positioning pin 220 is mounted on the top of the positioning seat 210, the positioning pin 220 is inserted into the mounting hole 130, and the top of the positioning seat 210 abuts against the surface of the bottom frame 110 away from the middle rib 120 of the bottom frame. The positioning pin 220 is installed at the top of the positioning seat 210, the positioning pin 220 is inserted into the installation hole 130, positioning of the main bearing cap 100 is achieved, the top of the positioning seat 210 abuts against the surface, away from the bottom frame 110, of the bottom frame middle rib 120, supporting of the main bearing cap 100 is achieved, positioning of the main bearing cap 100 and supporting of the main bearing cap 100 are achieved through the positioning piece 21, compared with the positioning and supporting of the main bearing cap 100, the number of parts is reduced, occupied space is reduced, and flexible layout is facilitated.

In some embodiments, the top of the positioning pin 220 is provided with a circular arc guiding surface 221. Through the top of locating pin 220 is provided with circular arc guide surface 221, the mounting hole 130 of being convenient for overlaps locating pin 220 is superior to the structure of top and side right angle transition, and circular arc guide surface 221 can not cause the damage to the inner wall of mounting hole 130.

In some embodiments, the two positioning members 21 are respectively engaged with the mounting holes 130 on the middle ribs 120 of the bottom frame at both ends. Through the cooperation of setting element 21 and the mounting hole 130 on the intermediate muscle 120 of underframe that is located both ends, not only can increase the error tolerance of setting element 21's position, support the both ends of underframe 110 moreover, support the effect better.

In some embodiments, the bottom frame middle rib 120 includes at least three, and the machining fixture further includes a support assembly 4 mounted on the bottom plate 1, where the support assembly 4 includes at least two main support members 31, and two main support members 31 are supported at positions of the bottom frame 110 corresponding to the middle bottom frame middle rib 120. As shown in fig. 2, the number of the supporting ribs is 4, the supporting assembly 4 comprises 4 main supporting members 31, the 4 main supporting members 31 are respectively supported below the bottom frames 110, two middle bottom frame middle ribs 120, and 1 main supporting member 31 is respectively arranged below two ends of each bottom frame middle rib 120.

In some embodiments, since only one positioning member 21 is supported below the middle ribs 120 of the bottom frame at two ends, no support is supported below the other side of the middle ribs 120 of the bottom frame at two ends, and the support is asymmetric, so that the main bearing cap 100 is easily damaged due to uneven stress, the support assembly 4 further includes two auxiliary support members 42, the two auxiliary support members 42 are respectively supported at the bottom of the bottom frame 110, and the two auxiliary support members 42 are respectively located below the middle ribs 120 of the same bottom frame with the two positioning members 21, and air detection holes 421 are formed at the top of the two auxiliary support members 42, and are used for detecting whether the bottom of the bottom frame 110 is completely attached to the top of the auxiliary support member 42. The two auxiliary supporting pieces 42 and the two positioning pieces 21 are respectively positioned below the same bottom frame middle rib 120, and are used for carrying out auxiliary supporting on the lower parts of the other sides of the bottom frame middle ribs 120 at the two ends, so that the main bearing cap 100 is prevented from being damaged due to uneven stress. Whether the bottom of the bottom frame 110 and the top of the auxiliary supporting piece 42 are completely attached or not is detected through the air detection hole 421, and the clamping check of the clamp is fast, so that the installation efficiency of the clamp can be improved, and the machining efficiency is improved.

In some embodiments, the main bearing cap 100 further comprises a water spraying gun 5 arranged on the side surface of the base plate 1 and an air nozzle 6 above the base plate 1, wherein the water spraying gun 5 is used for spraying water to the main bearing cap 100; the outlet of the air tap 6 is directed to the positioning member 21, the main support member 31 and the auxiliary support member 42 for air injection to clean the top support surface. The water gun 5 is used for spraying water to the main bearing cap 100, so that scrap iron on the surface of the main bearing cap 100 can be cleaned, and the scrap iron can be cooled in the machining process, so that the machining quality is improved; the air nozzles 6 are used for jetting air to the positioning member 21, the main supporting member 31 and the auxiliary supporting member 42 to clean the supporting surface at the top, and clean the positioning surface, so that the three are tightly attached to the bottom of the bottom frame 110.

On the basis of the above technical solution, it is preferable to further include a base 7, the base 7 is slidably mounted on the machined table 200, and the base plate 1 is mounted on the base 7. The base 7 slides on the machined workbench 200 and can be used for machining at a plurality of stations, so that the main bearing cap 100 can be machined in an omnibearing manner, and the machining efficiency is improved. Specifically, the four-axis assembly comprises two four-axis assemblies 8, wherein the two four-axis assemblies 8 are arranged on the base 7, and two ends of the bottom plate 1 are connected with the two four-axis assemblies 8.

In some embodiments, the base plate 1 is further provided with a tool setting seat 9, so that rapid tool setting is facilitated, and machining efficiency is improved.

The working principle of the machining clamp for the main bearing cap of the engine cylinder body is as follows: the pressing plate 320 is rotated to be parallel to the middle rib 120 of the bottom frame, the main bearing cap 100 is placed in the middle rib, the two mounting holes 130 are sleeved on the two positioning pieces 21, the surface, away from the middle rib 120 of the bottom frame, of the bottom frame 110 is pressed on the positioning pieces 21, the circumferential rotation of the main bearing cap 100 is limited, after the main bearing cap 100 is placed in the middle rib 120 of the bottom frame, the pressing plate 320 is rotated to be perpendicular to the middle rib 120 of the bottom frame, then the pressing plate 320 descends to enable the two ends of the pressing plate 320 to respectively press against one circular arch 122, the compression of the main bearing cap 100 is achieved, the displacement of the main bearing cap 100 in the vertical direction is limited, the main bearing cap 100 can be effectively prevented from moving in the machining process through limiting the position of the circumferential direction and the vertical direction, poor machining size is avoided, and machining precision is improved.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.

Claims

1. Machining fixture for a main bearing cap of an engine block, the main bearing cap (100) comprising a bottom frame (110) and a plurality of bottom frame intermediate ribs (120) connected with the bottom frame (110), and a plurality of mounting holes (130) penetrating the bottom frame (110) and the bottom frame intermediate ribs (120), the bottom frame intermediate ribs (120) comprising a dome (122) and two legs (121), the dome (122) being located between the two legs (121), characterized by comprising a bottom plate (1), and a positioning assembly (2) and a compacting assembly (3) mounted on the bottom plate (1), wherein:

the positioning assembly (2) comprises at least two positioning pieces (21), wherein the at least two positioning pieces (21) are respectively and partially inserted into the corresponding at least two mounting holes (130) and support the bottom frame (110) away from the surface of the middle rib (120) of the bottom frame;

the pressing assembly (3) comprises at least one pressing piece (31), the pressing piece (31) comprises a pressing seat (310) and a pressing plate (320), the pressing seat (310) is installed on the bottom plate (1), the pressing plate (320) is rotatably connected with the pressing seat (310) and can move along the vertical direction, and when the pressing plate (320) rotates to be perpendicular to the middle rib (120) of the bottom frame, the pressing plate (320) descends to the two ends of the pressing plate (320) respectively support against one circular arch (122).

2. The machining fixture for a main bearing cap of an engine block according to claim 1, wherein the pressing member (31) further comprises a hydraulic rod (330), the hydraulic rod (330) is vertically disposed in the pressing seat (310), the hydraulic rod (330) is capable of being lifted and rotated, and the pressing plate (320) is connected with the hydraulic rod (330).

3. Machining fixture for main bearing caps of engine blocks according to claim 2, characterized in that the pressure plate (320) comprises a connecting plate (321) and two pressing parts (322), the connecting plate (321) is connected with the hydraulic rod (330), the two pressing parts (322) are respectively connected with two ends of the connecting plate (321), the pressing parts (322) are provided with arc pressing surfaces (3221), and the arc pressing surfaces (3221) are used for pressing against the inner wall of the arc (122).

4. The machining fixture for a main bearing cap of an engine block according to claim 1, wherein the positioning member (21) comprises a positioning seat (210) and a positioning pin (220), the positioning seat (210) is mounted on the bottom plate (1), the positioning pin (220) is mounted on the top of the positioning seat (210), the positioning pin (220) is inserted into the mounting hole (130), and the top of the positioning seat (210) abuts against a surface, away from the bottom frame middle rib (120), of the bottom frame (110).

5. A machining fixture for a main bearing cap of an engine block as claimed in claim 4, characterized in that the top of the locating pin (220) is provided with a circular arc guiding surface (221).

6. A machining fixture for a main bearing cap of an engine block according to claim 1, wherein the two positioning members (21) are respectively engaged with mounting holes (130) provided in the intermediate ribs (120) of the bottom frame at both ends.

7. A machining fixture for a main bearing cap of an engine block as claimed in claim 6, wherein said bottom frame intermediate rib (120) comprises at least three, said machining fixture further comprising a support assembly (4) mounted to said bottom plate (1), said support assembly (4) comprising at least two main support members (41), two of said main support members (41) being supported in positions of said bottom frame intermediate rib (120) corresponding to the middle of said bottom frame (110).

8. The machining fixture for the main bearing caps of the engine block according to claim 7, wherein the supporting assembly (4) further comprises two auxiliary supporting pieces (42), the two auxiliary supporting pieces (42) are respectively supported at the bottom of the bottom frame (110), the two auxiliary supporting pieces (42) are respectively located below the same middle rib (120) of the bottom frame with the two positioning pieces (21), air detection holes (421) are formed in the tops of the two auxiliary supporting pieces (42), and the air detection holes (421) are used for detecting whether the bottom of the bottom frame (110) is completely attached to the top of the auxiliary supporting pieces (42).

9. The machining fixture for the main bearing caps of the engine block according to claim 8, further comprising a water gun (5) arranged on the side of the base plate (1) and an air tap (6) above the base plate (1), wherein the water gun (5) is used for spraying water to the main bearing caps (100); the outlet of the air tap (6) faces the positioning piece (21), the main support piece (41) and the auxiliary support piece (42) and is used for spraying air to clean the supporting surface of the top.

10. A machining fixture for a main bearing cap of an engine block as claimed in any one of claims 1-9, further comprising a base (7), said base (7) being slidably mounted on a machined table (200), said base plate (1) being mounted on said base (7).