CN111998058B

CN111998058B - Plastic speed reducer, preparation method and mold for molding plastic speed reducer box

Info

Publication number: CN111998058B
Application number: CN202010914779.3A
Authority: CN
Inventors: 钟丹
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-09-03
Filing date: 2020-09-03
Publication date: 2023-12-19
Anticipated expiration: 2040-09-03
Also published as: CN111998058A

Abstract

The invention discloses a plastic speed reducer, a preparation method and a die for forming a plastic speed reducer box, and relates to the field of aquaculture, and the technical scheme is characterized in that an inner insert of a bearing chamber can support an input shaft and an output shaft, a supporting block at one side of the input shaft extends upwards, and a bearing seat for connecting the two is arranged at the upper part; the plastic box body is not born with the acting force of the part, so that the torsion of the flange position of the box body is removed, the deformation problem of the box body is fundamentally solved, and the noise problem generated by long-time use is jointly removed in a deformation-free state.

Description

Plastic speed reducer, preparation method and mold for molding plastic speed reducer box

Technical Field

The invention relates to the field of aquaculture equipment, in particular to a plastic speed reducer, a preparation method and a die for forming a plastic speed reducer box body.

Background

An aerator is a machine commonly used in fishery. The main function of the water-based oxygen-free fish tank is to increase the oxygen content in water so as to ensure that fish in the water cannot be anoxic, and simultaneously inhibit the growth of anaerobic bacteria in the water, thereby preventing the deterioration of pool water and threatening the living environment of fish.

The reduction gearbox is used in the power part of the aerator, and the box body of the reduction gearbox is an aluminum piece or a casting, so that on one hand, the weight is high, the buoyancy required to be provided in water is high, and on the other hand, the aerator is easy to rust and is not suitable for the aquaculture industry.

At present, china patent with publication number CN107685424B discloses a plastic reduction gearbox of a waterwheel aerator, which comprises a plastic reduction gearbox shell and a reduction gear, wherein a motor is basically and vertically fixed on the plastic reduction gearbox, a motor shaft drives a small spiral bevel gear, the small spiral bevel gear drives a large spiral bevel gear, the large spiral bevel gear is arranged on a shaft of a small cylindrical gear, the small cylindrical gear drives a large cylindrical gear, and the large cylindrical gear is arranged on an output shaft; two bearing chambers are respectively arranged on two sides of the plastic reduction gearbox, and the two bearing chambers are respectively embedded with an insert, or the two inserts are arranged to be integrally embedded at bearing positions on two sides of the plastic reduction gearbox shell. The plastic reduction gearbox is provided with an upward connecting port which can be placed into a gear and is matched with a motor flange, the connecting port is provided with a flange, the flange is provided with a bolt hole opposite to the motor flange, the connecting port can be provided with a metal insert or a backing plate for reinforcement, the motor and the plastic reduction gearbox are fastened and butted by bolts, and the plastic reduction gearbox and the motor flange are connected to form a closed box body.

Above-mentioned plastic reduction gearbox is because plastic reduction gearbox is different with traditional cast iron reduction gearbox's box, and plastic box's structural strength is relatively poor, and the flange connection of motor end cover is on plastic reduction gearbox's flange, and motor spindle rotation utilizes the gear to transmit power. The centrifugal force generated by the rotation of the motor spindle makes the radial load born by the plastic reduction gearbox larger, and torsion is generated between the box body of the plastic reduction gearbox and the flange, so that the plastic reduction gearbox is concentrated in the area to deform. After the box body is deformed, the plane where the flange is located is inclined, so that a motor spindle connected with the flange is inclined, the meshing angle of the internal gear is changed, the abrasion of the gear is increased, the service life is influenced, and larger noise is generated.

Disclosure of Invention

The invention aims to provide a plastic speed reducer which has the advantages of high structural strength of a box body, motor output torsion resistance, long service life and low noise.

The technical aim of the invention is realized by the following technical scheme:

a plastic speed reducer comprises a box body made of plastic, wherein a cavity and a connecting port are arranged in the box body, and a flange is arranged on the connecting port;

an input shaft and an output shaft are arranged in the cavity, the input shaft is provided with a driven spiral bevel gear, and a differential gear assembly is arranged between the input shaft and the output shaft;

bearing chambers communicated with the chambers are further arranged on two side walls of the box body corresponding to the input shaft and the output shaft, and inserts are arranged in the two bearing chambers on the same side;

the embedded part comprises a ring body which is integrally connected and installed on the box body and used for bearing installation, a supporting block which extends upwards to the connecting port is arranged on one side, close to the input shaft, of the ring body, an embedded groove for the supporting block to penetrate is formed in the box body, a bearing seat and a driving spiral bevel gear which is arranged in the bearing seat and is rotationally connected by the bearing are radially connected between the two supporting blocks which extend to the connecting port, a motor flange end cover is embedded on the flange, and the main shaft is linked with the driving spiral bevel gear; a lubrication channel which is staggered with the bearing seat is formed between the side edge of the bearing seat and the box body.

By adopting the technical scheme, the bearing inner insert can support the input shaft and the output shaft, the supporting block at one side of the input shaft extends upwards and is provided with the bearing seat at the upper part for connecting the input shaft and the output shaft, the bearing seat, the two inserts and the input shaft form a frame structure in a relative state, the motor main shaft acts on the driving spiral bevel gear, the driving spiral bevel gear transmits the centrifugal force generated by the rotation of the motor to the bearing seat, and the bearing seat, the two inserts and the input shaft form the frame structure in the relative state to bear acting force; the plastic box body is not born with the acting force of the part, so that the torsion of the flange position of the box body is removed, the deformation problem of the box body is fundamentally solved, and the noise problem generated by long-time use is jointly removed in a deformation-free state; because the setting of bearing frame for be formed with the lubrication channel with the bearing frame dislocation between bearing frame side and the box, each gear assembly of speed reducer inside can take the lubrication liquid that makes in the cavity inside splash at the in-process of operation, and lubrication channel's existence makes lubrication liquid lubricate bearing frame and the initiative spiral bevel gear on upper portion, and this part directly bears the atress of motor main shaft, and the lubrication constantly has reduced the wearing and tearing of this part, more near the delay life of a portion.

Further set up: the bearing seat comprises two lugs which are connected with the supporting blocks of the inserts through bolts.

Through adopting above-mentioned technical scheme, two lugs can be dismantled with the bearing block and be connected, components of a whole that can function independently design, make things convenient for dismouting and maintenance.

Further set up: the differential gear assembly comprises a driving bevel gear arranged on the input shaft and a driven bevel gear arranged on the output shaft, the tooth thicknesses of the driven bevel gear and the driving bevel gear are equal, and the diameter of the driven bevel gear is smaller than that of the driving bevel gear.

By adopting the technical scheme, helical gear transmission is superior to straight teeth, and the helical gear transmission can compact the center distance for high-speed heavy load, and has the advantages of small volume, light weight, large transmission torque, stable starting and fine transmission ratio grading.

Further set up: the box body is positioned outside the bearing chamber and is sealed by mechanical seal or filler.

By adopting the technical scheme, the mechanical seal is optimized, the mechanical seal state is stable in long-term operation, the friction power consumption is small, the leakage amount is extremely small, and the service life in oil and water medium can reach about 2 years or even longer. The packing seal is chosen with consideration of cost.

Further set up: the highest plane of the bearing seat is lower than the plane of the flange.

By adopting the technical scheme, the lubricating liquid in the cavity is driven by the internal gear component to splash, the end face of the bearing seat is slightly lower, and the purpose of lubricating the driving spiral bevel gear and the bearing from bottom to top or from top to bottom can be simultaneously achieved.

The invention aims to provide a method for preparing a box body of a speed reducer, and the prepared box body of the speed reducer has the advantages of high structural strength, motor output torsion resistance, long service life and low noise.

a method of manufacturing a case of a speed reducer, comprising:

step S01: preparing raw materials for forming the box body, wherein the raw materials are plastics;

step S02: forming the box body by adopting an injection mold;

step S03: after demoulding, the box body is fixed to the upper four-axis machining of the vertical machining center by using a fixture, and a caulking groove for the supporting block to penetrate is cut.

Through adopting above-mentioned technical scheme, firstly with the box of mould shaping speed reducer, place the box in machining center processing out corresponding caulking groove again, the shaping of time sequential, machining precision is up to standard, has reduced mould transformation cost.

Further set up: in the step S01, PA66 is selected as a box raw material.

By adopting the technical scheme, the box body has better impact resistance and high mechanical strength, and can resist corrosion of acid, alkali, most inorganic salt water solutions, haloalkanes, hydrocarbons, esters, ketones and the like.

The invention further aims to provide an injection mold for molding the plastic speed reducer box, and the molded speed reducer box has the advantages of high structural strength, motor output torsion resistance, long service life and low noise.

an injection mold for molding a plastic reduction box, the injection mold comprising: the movable die plate and the fixed die plate which linearly reciprocate are provided with a movable die seat plate and a cushion block at the rear side of the movable die plate, and the fixed die plate is provided with a cavity and a pouring port communicated into the cavity; the movable template is provided with a main core and an inclined top for forming the cavity, the lower edge of the main core is provided with a crescent block corresponding to the position of the box body supporting block, and the crescent block is provided with a groove corresponding to the supporting block; the bottom of the main core is provided with a core plate for integrally forming the flange, the core plate is provided with a top block for sealing the molding oil, and the top block is abutted to the inclined top; and the movable mould plate is also provided with side sliding blocks which are coated on two sides of the mould core and are used for carrying out lateral clutch to form bearing chambers on two sides of the box body, and the main mould core, the inclined top, the top block and the side sliding blocks extend into the cavity to form a forming cavity for forming the box body.

Through adopting above-mentioned technical scheme, injection mold takes shape with the box shaping of plastics speed reducer to utilize the shape of crescent moon piece and recess, the required entity structure of passageway that the shaping supporting shoe worn to establish, after the convenient shaping, to the entity structure secondary operation of this part, finally form the caulking groove that supplies the supporting shoe to wear to establish.

Further set up: the inclined roof comprises an inclined roof body and an inclined roof guide rod, and inclined guide structures for linear sliding of the inclined roof guide rod are arranged on the main core and the core plate.

By adopting the technical scheme, the forming cavity with better inclined top is adopted, and the demoulding is also better.

Further set up: the inclined guide structure comprises a guide groove arranged on the main core and a guide part embedded on the inclined top and sliding with the guide groove, wherein the groove wall of the guide groove is provided with a linear sliding rib for limiting the guide part, and the shape of the guide part is matched with the guide groove.

Through adopting above-mentioned technical scheme, the setting of sliding bead connects the limited sliding of guide in the guide way, avoids it to deviate from.

In summary, the invention has the following beneficial effects: 1. the bearing seat, the two inserts are added, the bearing seat, the two inserts and the input shaft form a frame structure in a relative state, the stress point of the original force after transmission is changed, the centrifugal force generated by the rotation of the motor main shaft acts on the bearing seat of the plastic speed reducer, the bearing seat directly bears radial load, the plastic box body does not bear torsion any more, the axial position of the motor main shaft is ensured to be unchanged, the internal gear engagement precision is good, the service life is prolonged, and the noise problem caused by poor gear engagement state is fundamentally avoided.

2. The presence of the lubrication channels allows for more adequate lubrication of the interior, further increasing its useful life.

Drawings

Fig. 1 is a schematic structural view of a speed reducer according to a first preferred embodiment;

fig. 2 is an exploded view of the speed reducer according to the first preferred embodiment;

FIG. 3 is a schematic view of a frame structure with the bearing housing, two inserts and input shaft in opposition;

FIG. 4 is a schematic view of an injection mold in a second preferred embodiment;

FIG. 5 is a schematic view of an exploded construction of an injection mold in a second preferred embodiment;

fig. 6 is a schematic view of a pitched roof structure in a second preferred embodiment.

100, a box body; 101. a base; 102. a connection port; 103. sealing with oil; 104. a flange; 105. an input shaft; 106. an output shaft; 107. a driving helical gear; 108. a passive helical gear; 109. a bearing chamber; 110. an insert; 111. a interlink; 112. a support block; 113. a caulking groove; 114. a threaded column; 115. a support lug; 116. a central portion; 117. a bearing seat; 118. a drive spiral bevel gear; 119. a passive spiral bevel gear; 120. a lubrication channel; 121. mechanical sealing;

200. a movable template; 201. a stationary mold plate; 202. a movable die base plate; 203. a cushion block; 204. pouring the port; 205. a primary core; 206. a core plate; 207. a pitched roof; 208. an inclined top body; 209. obliquely pushing up the guide rod; 210. a guide part; 211. a guide groove; 212. a sliding rib; 213. a side slider; 214. crescent blocks; 215. a groove; 216. and (5) a top block.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

First preferred embodiment:

a plastic speed reducer, as shown in figure 1, comprises a box body 100, wherein a cavity is formed in the box body 100, a base 101 is arranged at the bottom of the box body, a connection port 102 and an oil seal port 103 are arranged at the top of the box body, and a flange 104 is arranged on the connection port 102. The plastic speed reducer is used in the aquaculture industry and needs to be soaked in water, so that the box body 100 is made of plastic in consideration of dead weight, corrosion resistance and aging resistance, the adopted molding plastic is PA66, and PA66 is engineering plastic, and compared with cast iron, the plastic speed reducer has the advantages of reducing dead weight, having better impact resistance, being high in mechanical strength and being capable of resisting corrosion.

As shown in fig. 2, an input shaft 105 and an output shaft 106 are provided in the chamber, and a differential gear assembly is provided between the input shaft 105 and the output shaft 106. The differential gear assembly comprises a driving bevel gear 107 arranged on the input shaft 105 and a driven bevel gear 108 arranged on the output shaft 106, the tooth thickness of the driven bevel gear 108 is equal to that of the driving bevel gear 107, the diameter of the driven bevel gear 108 is smaller than that of the driving bevel gear 107, and the rotation speed is converted by utilizing the diameter ratio.

The two side walls of the box 100 corresponding to the input shaft 105 and the output shaft 106 are also provided with bearing chambers 109 communicated with the cavities, the input shaft 105 and the output shaft 106 are mounted on the box 100 through bearings, the bearing chambers 109 of the box 100 are internally provided with bearings which need to be mounted, and the bearings need to bear force, so that the bearing chambers 109 are internally provided with inserts 110. The insert 110 comprises an integrally formed interlink 111 and a supporting block 112 radially extending to the outer side of the interlink 111, the interlink 111 is installed in a bearing chamber 109 of the box 100, the bearing is installed in the interlink 111, the supporting block 112 is arranged on the interlink 111 close to one side of the input shaft 105 and is located on the interlink 111, the position extends upwards to the connecting port 102, an embedded groove 113 for the supporting block 112 to penetrate is formed in the box 100, the interlink 111 is in an 'infinity' type arrangement corresponding to the input shaft 105 and the output shaft 106, a threaded column 114 is arranged at the edge of the interlink 111, and the interlink 111 is axially connected to the inner side in the bearing chamber 109.

The supporting blocks 112 are arranged on two sides of the shaft ends of the input shaft 105 and the output shaft 106 of the box body 100, the supporting blocks 112 extend to the connecting port 102, a bearing seat 117 is radially connected between the two supporting blocks 112, the bearing seat 117 comprises a central part 116 and two lugs 115 arranged on the outer side of the central part 116, the lugs 115 are connected with the supporting blocks 112 of the insert 110 through bolts, the central part 116 is provided with a bearing and a driving spiral bevel gear 118 rotationally connected by the bearing, the input shaft 105 is provided with a driven spiral bevel gear 119, a motor flange end cover is embedded on the flange 104, a main shaft is linked with the driving spiral bevel gear 118, the motor main shaft is linked with the driving spiral bevel gear 118 to rotate, the driving spiral bevel gear 118 is meshed with the driven spiral bevel gear 119 to drive the input shaft 105 to rotate, a differential gear assembly between the output shaft 106 and the output shaft 106 is subjected to speed reduction change, and finally the converted rotating speed is output by the output shaft 106.

As shown in fig. 3, the supporting block 112 is disposed on the interlink 111 near one side of the input shaft 105 such that the bearing housing 117, the two inserts 110 and the input shaft 105 form a frame structure in a relative state, and the motor main shaft acts on the drive spiral bevel gear 118, in which state the drive spiral bevel gear 118 transfers centrifugal force generated by the rotation of the motor to the bearing housing 117 and the bearing housing 117, the two inserts 110 and the input shaft 105 form a frame structure in a relative state to carry the force. After the motor is added, the stress of the speed reducer is tested, a plastic reduction gearbox of the waterwheel aerator is disclosed in China patent with publication number of CN107685424B, the motors with output power of 0.75KW and 1.5KW are respectively used for testing, the stress of the gearbox body 100 is concentrated on the flange 104, and a large torsion is generated at the junction between the flange 104 and the gearbox body 100. The box body 100 of the plastic speed reducer adopts motor tests of 0.75KW and 1.5KW output power respectively, the stress of the box body 100 is concentrated on the motor end cover on the upper part of the flange 104, the motor end cover is cast iron, the stress is concentrated on the end cover of the motor, the deformation of the box body 100 is not caused, and a series of problems after the deformation of the box body 100 are radically avoided.

A lubrication channel 120 which is dislocated with the bearing seat 117 is formed between the side edge of the bearing seat 117 and the box body 100, specifically, the lubrication channel 120 is dislocated with the support lug 115 of the bearing seat 117, and the highest plane of the bearing seat 117 is lower than the plane of the flange 104. So set up, each gear assembly of speed reducer inside can take the inside lubrication liquid that makes in the cavity to splash at the in-process of operation, and lubrication liquid can be to lubrication channel 120 and go up, lubricate bearing frame 117 and the initiative spiral bevel gear 118 on upper portion, and this part directly bears the atress of motor main shaft, and the wearing and tearing of this part have been greatly reduced in the moment lubrication.

As shown in fig. 1, the housing 100 is positioned outside the bearing housing 109 using a mechanical seal 121 or a packing seal. The mechanical seal 121 is preferable, the state of the mechanical seal 121 is stable in long-term operation, the friction power consumption is small, the leakage amount is extremely small, and the service life in oil and water media can reach about 2 years or even longer. The packing seal is chosen with consideration of cost.

Second preferred embodiment:

an injection mold for molding a plastic reduction box, as shown in fig. 4, the injection mold comprising: the movable mold plate 200 and the fixed mold plate 201 which move linearly and reciprocally are provided with a movable mold base plate 202 and a cushion block 203 at the rear side of the movable mold plate 200, the fixed mold plate 201 is provided with a cavity and a pouring port 204 communicated into the cavity, and the movable mold plate 200 and the fixed mold plate 201 are standard mold frames in an injection mold.

As shown in fig. 5, a main core 205 for forming the cavity is provided on the movable mold plate 200, and a core plate 206 for integrally forming the flange 104 is provided at the bottom of the main core 205, and the core plate 206 is embedded in the movable mold plate 200 to move together with the movable mold plate 200. The top of speed reducer has a connector 102, and the bore of connector 102 is for the external diameter to be little for the cavity is inside, in order to be convenient for the drawing of patterns after the inside cavity shaping, still is equipped with the oblique top 207 that is used for the cavity of shaping speed reducer box 100 with main core 205 on the movable mould board 200, and oblique top 207 includes oblique top body 208 and oblique top guide bar 209, is equipped with the oblique guide structure that supplies oblique top guide bar 209 linear slip on main core 205 and the core 206. Guiding angled roof 207 with the angled guide results in a lateral amount of expansion and contraction that facilitates removal of the mold from connection port 102.

Specifically, referring to fig. 5 and 6, the inclined guide structure includes a guide groove 211 provided on the main core 205 and a guide portion 210 embedded on the inclined top 207 to slide with the guide groove 211, a groove wall of the guide groove 211 is provided with a linear sliding rib 212 to limit the guide portion 210, and a shape of the guide portion 210 is adapted to the guide groove 211. The provision of the sliding rib 212 locks the relative sliding state of both the guide 210 and the guide groove 211, ensuring that the beveled roof 207 is restrained from reciprocal movement within the mould.

A top block 216 of the molding oil seal 103 is arranged on the core plate 206, and the top block 216 is abutted against the inclined top 207; the movable mold plate 200 is also provided with side sliding blocks 213 which are coated on two sides of the mold core to carry out lateral clutch and are used for forming bearing chambers 109 on two sides of the box body 100, and the main core 205, the inclined top 207, the top block 216 and the side sliding blocks 213 extend into the cavity to form a forming cavity for forming the box body 100.

As a structure of the box 100 of the new speed reducer, the structure of the mold is changed adaptively, a crescent block 214 corresponding to the position of the supporting block 112 of the box 100 is arranged at the lower edge of the main core 205, a groove 215 corresponding to the supporting block 112 is arranged on the crescent block 214, the box 100 injection molded by the mold is provided with a molding entity of the caulking groove 113 by the arrangement of the part, and the caulking groove 113 with the size corresponding to the supporting block 112 is cut by utilizing the vertical machining center on the entity of the box 100 for the supporting block 112 to penetrate.

Meanwhile, the mold is also provided with an ejection mechanism, the ejection mechanism is provided with a combination of a thimble fixing plate and a thimble which are conventional in the market, a thimble hole is formed in the core plate 206, and after the box body 100 is molded, the box body is ejected by the ejection mechanism, and the ejection mechanism is selected and matched in the part, so that the ejection mechanism is not shown in the figure.

Third preferred embodiment:

a method of manufacturing a case of a speed reducer, comprising:

step S01: preparing raw materials for forming the box body 100, wherein the raw materials are plastics, and the raw materials of the box body 100 are PA66;

step S02: forming a box 100 of the speed reducer by using the injection mold in the first preferred embodiment;

step S03: after the box body 100 is molded, the box body 100 is demolded, and the box body 100 is fixed to a vertical machining center by using a fixture to perform four-axis machining, and a caulking groove 113 for the supporting block 112 to penetrate is cut.

Fourth preferred embodiment:

an aerator is provided with a speed reducer in a first preferred mode.

The above-described embodiments are provided for illustration only and not for limitation of the present invention, and modifications may be made to the embodiments without creative contribution by those skilled in the art after reading the present specification, as long as they are protected by patent laws within the scope of claims of the present invention.

Claims

1. A plastic speed reducer comprises a box body (100) made of plastic, wherein a cavity and a connecting port (102) are arranged in the box body (100), and a flange (104) is arranged on the connecting port (102);

an input shaft (105) and an output shaft (106) are arranged in the cavity, the input shaft (105) is provided with a passive spiral bevel gear (119), and a differential gear assembly is arranged between the input shaft (105) and the output shaft (106);

two side walls of the box body (100) corresponding to the input shaft (105) and the output shaft (106) are also provided with bearing chambers (109) communicated with the cavities, and inserts (110) are arranged in the two bearing chambers (109) at the same side;

the method is characterized in that: the insert (110) comprises a interlink (111) which is integrally connected and installed on the box body (100) and is used for bearing installation, a threaded column (114) is arranged at the edge of the interlink (111), and the interlink (111) is axially connected to the inner side in the bearing chamber (109); a supporting block (112) extending upwards to the connecting port (102) is arranged on one side, close to the input shaft (105), of the interlink (111), an embedded groove (113) for the supporting block (112) to penetrate is arranged on the box body (100), a bearing seat (117) and a driving spiral bevel gear (118) which is arranged in the bearing seat (117) and is rotationally connected by a bearing are radially connected between the two supporting blocks (112) extending to the connecting port (102), a motor flange end cover is embedded on the flange (104), and the main shaft is in linkage with the driving spiral bevel gear (118);

a lubrication channel (120) which is dislocated with the bearing seat (117) is formed between the side edge of the bearing seat (117) and the box body (100).

2. The plastic speed reducer of claim 1, wherein: the bearing seat (117) comprises two lugs (115), and the lugs (115) are connected with the supporting blocks (112) of the insert (110) through bolts.

3. The plastic speed reducer of claim 1, wherein: the differential gear assembly comprises a driving bevel gear (107) arranged on the input shaft (105) and a driven bevel gear (108) arranged on the output shaft (106), the tooth thicknesses of the driven bevel gear (108) and the driving bevel gear (107) are equal, and the diameter of the driven bevel gear (108) is smaller than that of the driving bevel gear (107).

4. The plastic speed reducer of claim 1, wherein: the box body (100) is positioned outside the bearing chamber (109) and is sealed by mechanical seal (121) or packing.

5. The plastic speed reducer of claim 1, wherein: the highest position of the bearing seat (117) is lower than the plane of the flange (104).

6. An injection mold for molding a casing of a plastic speed reducer according to any one of claims 1 to 5, characterized in that: the injection mold includes: a movable die plate (200) and a fixed die plate (201) which move linearly and reciprocally, wherein a movable die base plate (202) and a cushion block (203) are arranged at the rear side of the movable die plate (200), and the fixed die plate (201) is provided with a die cavity and a pouring port (204) communicated into the die cavity; a main core (205) and an inclined top (207) for forming the cavity are arranged on the movable template (200), a crescent block (214) corresponding to the supporting block (112) of the box body (100) is arranged at the lower edge of the main core (205), and a groove (215) corresponding to the supporting block (112) is arranged on the crescent block (214); the bottom of the main core (205) is provided with a core plate (206) for integrally forming the flange (104), the core plate (206) is provided with a top block (216) for forming the oil seal (103), and the top block (216) is abutted to the inclined top (207); the movable template (200) is also provided with side sliding blocks (213) which are coated on two sides of the core and are used for laterally clutching bearing chambers (109) on two sides of the forming box body (100), and the main core (205), the inclined top (207), the top blocks (216) and the side sliding blocks (213) extend into the cavity to form a forming cavity for forming the box body (100).

7. The injection mold for molding a plastic speed reducer casing according to claim 6, wherein: the inclined roof (207) comprises an inclined roof body (208) and an inclined roof guide rod (209), and inclined guide structures for linear sliding of the inclined roof guide rod (209) are arranged on the main core (205) and the core plate (206).

8. The injection mold for molding a plastic speed reducer casing according to claim 7, wherein: the inclined guide structure comprises a guide groove (211) arranged on the main core (205) and a guide part (210) embedded on the inclined top (207) and sliding with the guide groove (211), wherein the groove wall of the guide groove (211) is provided with a linear sliding rib (212) for limiting the guide part (210), and the shape of the guide part (210) is matched with that of the guide groove (211).

9. A method of manufacturing a box for a speed reducer according to any one of claims 1 to 5, characterized in that: comprising the following steps:

step S01: preparing raw materials for forming the box body (100), wherein the raw materials are plastics;

step S02: forming the box body (100) by adopting an injection mold;

step S03: after demoulding, the box body (100) is fixed to a vertical machining center through a fixture, and a caulking groove (113) for the supporting block (112) to penetrate is cut.

10. The method of manufacturing a casing of a speed reducer according to claim 9, characterized in that: in the step S01, PA66 is selected as a raw material of the box body (100).