CN211249046U

CN211249046U - Press mounting device for timing chain wheel on crank of crankshaft

Info

Publication number: CN211249046U
Application number: CN201922303343.6U
Authority: CN
Inventors: 李红兵
Original assignee: TAIZHOU HONGXIN CRANKSHAFT CO Ltd
Current assignee: TAIZHOU HONGXIN CRANKSHAFT CO Ltd
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2020-08-14
Anticipated expiration: 2029-12-19

Abstract

The utility model provides a pressure equipment device that is used for timing sprocket on crank of bent axle belongs to pressure equipment technical field. The press fitting device solves the problems that the timing angle is not easy to control and the product percent of pass is low during press fitting. It includes base and die carrier, be fixed with the die head on the die carrier, the lower terminal surface of die head is fixed with the installation piece through the fastener, the center of installation piece is run through and is provided with the shape and the same mounting groove of sprocket in right time, it is provided with floating centre to slide along upper and lower direction in the die head, floating centre lower extreme passes from the center of mounting groove, be fixed with the locating piece on the base, the center of locating piece is equipped with down top, lower top axis and floating centre's axis looks collineation, it is equipped with the round pin post that can insert crank pin hole on the crank to be close to locating piece department on the base, be equipped with the friction structure. The press fitting device has the advantages of easy control of timing angles, high press fitting precision, high qualification rate, simple structure and the like.

Description

Press mounting device for timing chain wheel on crank of crankshaft

Technical Field

The utility model belongs to the technical field of the pressure equipment, a pressure equipment device that is used for timing sprocket on the crank of bent axle is related to.

Background

The crank shaft is a key part for converting linear motion of a cylinder piston into circular motion, generally comprises two symmetrically arranged cranks and a crank pin fixed between the two cranks, and is matched with a connecting rod with big ends and small ends at two ends, one end of the crank pin is inserted into a crank pin hole of one crank when the crank shaft is assembled, then the big ends of the connecting rod are sleeved on the crank pin hole, and finally the other end of the crank pin is inserted into a crank pin hole of the other crank, so that the crank shaft and connecting rod assembly is assembled. When a crankshaft connecting rod is actually used, a timing chain wheel needs to be pressed on a crank corresponding to a crankshaft, the timing chain wheel is an important component of an engine air distribution system, generally, a phase requirement, namely a timing angle, is required between a timing gear and a crank pin or a crank pin hole central line, and the accuracy of the timing angle ensures that an air valve can be opened or closed at correct time.

The timing chain wheel is basically pressed and assembled through a hydraulic press, but the timing angle is not easy to control when the traditional hydraulic press is used for pressing and assembling, and the yield is low. At present, aiming at the problem, the conventional mode is to assemble two cranks, crank pins and connecting rods into a crankshaft connecting rod assembly, and then fix the whole crankshaft connecting rod assembly on a press-fitting device to press-fit a timing chain wheel on the crankshaft crank. Wherein, in order to guarantee the angle of timing after the pressure equipment, the most common mode divide into two kinds among the current pressure equipment: one method is that a timing mark point is processed on a timing gear and a corresponding positioning point is arranged on a positioning mechanism of press-fitting equipment, and the mark point on the timing gear and the positioning point on the press-fitting equipment are aligned through naked eye judgment before assembly; another method is to position the crankshaft-connecting rod assembly with the small end hole of the connecting rod as the reference, and then to form a relationship corresponding to the timing angle between the crank pin and the timing sprocket by means of the connecting rod, such as a simultaneous drawing device of the crankshaft timing sprocket and the bearing disclosed in patent application No. 201610081596.1 and a press-fitting timing gear device of the crankshaft assembly disclosed in patent application No. 201620225427.6.

Disclosure of Invention

The utility model aims at the above-mentioned problem that prior art exists, provide a pressure equipment device that is used for timing sprocket on the crank of bent axle, solved the not wayward, the low problem of product percent of pass of angle in right time.

The purpose of the utility model can be realized by the following technical proposal:

a pressure equipment device for bent axle crank goes up timing sprocket, including base and the die carrier that can receive the driving piece drive to the base removal, be fixed with the die head on the die carrier, the lower terminal surface of die head is fixed with the installation piece through the fastener, the center of installation piece runs through and is provided with the mounting groove that the shape is the same with the timing sprocket, it is provided with floating centre to slide along upper and lower direction in the die head, floating centre lower extreme passes from the center of mounting groove, a serial communication port, the base on be fixed with the locating piece, the center of locating piece is equipped with down top, lower top's axis and floating centre's axis collineatly mutually, be close to locating piece department on the base and be equipped with the round pin post that can insert crank pin hole on the crank.

When the timing chain wheel needs to be pressed, a crank for forming the crank shaft is placed on the positioning block, the lower tip is pressed against a central hole at the large end of the crank, and meanwhile, a pin is ensured to be inserted into a crank pin hole in the crank, so that the positions of the crank and the crank pin hole are determined. Then, the timing chain wheel is placed in the mounting groove, and the friction structure acts on the timing chain wheel to prevent the timing chain wheel from falling off under the action of gravity. And then, controlling the driving piece to drive the die carrier to press downwards, enabling the floating center to move downwards along with the die carrier to be propped against the center hole of the small end of the crank, and enabling the floating center to be pushed upwards under the reaction, so that the small end of the crank penetrates through the center of the timing chain wheel. The timing chain wheel is finally pressed on the crank along with the continuous pressing of the die carrier.

Through the cooperation of the positioning block, the lower tip and the floating tip, the press-fitting device can directly fix the crank for forming the crankshaft to press-fit the timing chain wheel, and the timing angle after press-fitting of the timing chain wheel is ensured to meet the design requirement by using a crank pin hole in the crank as a reference, so that the qualification rate of products is improved. Compared with the conventional method that the timing chain wheel is pressed after the whole crankshaft is assembled, and the small end of the connecting rod is positioned to be used as the reference of the timing angle, certain machining errors exist when the connecting rod, the crank pin and the crank pin hole are machined, the machining errors are overlapped after the crankshaft is assembled to amplify the errors, and the timing chain wheel is pressed on the basis, so that the timing angle deviation is large. In the press fitting device, the cranks used for forming the crankshaft are directly fixed to press fit the timing chain wheel, and the crank pin holes on the cranks are used as references, so that the influence caused by errors between the connecting rod and the crank pin and between the crank pin and the crank pin hole is eliminated, the press fitting precision is improved, and the structure is simpler relatively. In addition, the crank is also required to be provided with a bearing, and the bearing is closer to the big end of the crank relative to the timing chain wheel, so that the bearing can be placed on the small end of the crank before press fitting, the synchronous press fitting of the bearing and the timing chain wheel can be realized by utilizing the pressure when the die carrier moves downwards, and the assembly efficiency of the whole crankshaft is improved.

In the press fitting device for the timing chain wheel on the crank of the crankshaft, the upper end surface of the positioning block is a plane, the center of the upper end surface of the positioning block is provided with the positioning hole, the lower tip is arranged in the positioning hole in a sliding manner, the positioning hole is internally provided with the lower spring, and the elastic force of the lower spring upwards acts on the lower tip.

The upper end face of the positioning block is a plane, so that the smoothness of the positioned crank can be ensured, the situation that the timing chain wheel is inclined in press fitting is avoided, and the press fitting precision is improved. Meanwhile, due to the arrangement of the lower spring, the lower tip and the crank can be in flexible contact, and the crank is prevented from being damaged due to overlarge press mounting force.

In the above pressing device for the timing sprocket on the crank of the crankshaft, the upper end of the pin is provided with the guide part, and the peripheral wall of the pin is provided with two symmetrically arranged convex arc surfaces.

The guide part is arranged, so that the pin column can be easily inserted into a crank pin hole on the crank, and meanwhile, two outer convex arc surfaces symmetrically arranged on the outer peripheral wall of the pin column are abutted against the inner peripheral surface of the crank pin hole to form clearance fit between the pin column and the crank pin hole, so that the coaxiality of the axis of the pin column and the central line of the crank pin hole is ensured to ensure the press-fitting precision.

In the press fitting device for the timing chain wheel on the crank of the crankshaft, the number of the fastening pieces is a plurality, the mounting block is provided with a plurality of arc-shaped adjusting grooves in a penetrating manner along the vertical direction, the adjusting grooves are distributed around the floating tip and are positioned at the outer edge close to the mounting block, and the fastening pieces penetrate through the corresponding adjusting grooves.

The press fitting can be carried out before press fitting, and if the timing angle is not in the design range after press fitting, each fastener can be loosened, so that the mounting block can be rotated to finely adjust the angle between the mounting groove and the axis of the pin column, and the press fitting precision is further improved. And the installation block does not receive circumferential acting force during press fitting, so that the problem that the installation block rotates to cause the angle between the installation groove and the axis of the pin column to deflect in the press fitting process is solved. In addition, each adjusting groove is arranged at the position close to the outer edge of the mounting block, so that the end part of each fastener can be prevented from touching the bearing to crush the bearing during press mounting.

In the above pressing device for the timing sprocket on the crank of the crankshaft, the adjusting groove sequentially comprises a first groove section with a larger groove width and a second groove section with a smaller groove width from bottom to top, the fastener is a fastening screw, the rod part of the fastener is positioned in the second groove section, the head part of the fastener is positioned in the first groove section, and the head part of the fastener is higher than the lower end surface of the mounting block or flush with the lower end surface of the mounting block.

The adjusting groove sequentially comprises a groove section I with a large groove width and a groove section II with a narrow groove width from bottom to top, the rod part of the fastener is positioned in the groove section II, the head part of the fastener is positioned in the groove section I, the head part of the fastener is higher than the lower end face of the mounting block or is flush with the lower end face of the mounting block, and therefore the fastener is not exposed, the possibility of influence on press mounting caused by the fact that the mounting block is adjustable is eliminated, and press mounting precision is guaranteed.

In the above-mentioned pressure equipment device for crank upper timing sprocket of bent axle, the die head in be equipped with the pilot hole, pilot sleeve is connected with to pilot hole internal thread, floating center's upper end is equipped with the sliding part, the sliding part slides and sets up in the pilot sleeve, be equipped with the through-hole with the pilot hole intercommunication on the die head, floating center passes the through-hole and for clearance fit between the two, is equipped with the spring in the pilot sleeve, the lower terminal surface of sliding part offsets with the diapire of pilot hole under the spring action of last spring and leans on.

When the die carrier moves downwards to press the timing chain wheel, the tip end part of the floating center is abutted against the center of the small end face of the crankshaft, the floating center overcomes the elasticity of the upper spring to move upwards relative to the die carrier under the reaction force, and thus the small end of the crank can enter the die head to press the timing chain wheel onto the crank. In the press fitting process, the elastic force of the upper spring still acts on the floating center, so that the crank is supported by the floating center and the lower center to be kept fixed, and the crank is prevented from being inclined to influence the press fitting precision.

In foretell a pressure equipment device for timing sprocket on crank of bent axle, the die head include cylindric body and be fixed in the cushion of body lower extreme, the installation piece is fixed in the lower extreme of cushion, the cushion center is run through and is provided with the hole of stepping down, the hole of stepping down is located between mounting groove and the through-hole, the internal diameter in the hole of stepping down is less than the biggest internal diameter of mounting groove and the internal diameter in the hole of stepping down is greater than the internal diameter of through-hole.

The crank has the reducing section that the external diameter is crescent from tip to main aspects, and the position of timing sprocket on the crank is located between reducing section and the main aspects, consequently needs set up the hole of stepping down between through-hole and mounting groove, and the tip upwards promotes and pass the through-hole floating in the tip during pressure equipment, and the reducing section then is located the hole of stepping down simultaneously, then the mounting groove just in time can be in the position of the required pressure equipment of timing sprocket.

In the above-mentioned pressure equipment device for crank timing sprocket of bent axle, the installing block side seted up the mounting hole, the mounting hole is linked together with the mounting groove, friction structure is including locating little spring and the steel ball in the mounting hole, the steel ball stretches into in the mounting groove under the spring action part of little spring.

The steel ball stretches into the mounting groove in the elastic force effect part of little spring, and when putting into the mounting groove with the sprocket in right time, the steel ball receives the extrusion of sprocket in right time and retracts into the mounting hole in, but the elasticity of little spring still acts on the sprocket in right time through the steel ball for the sprocket in right time can not receive the action of gravity and follow the mounting groove and accidentally deviate from, has guaranteed the reliability and the stability of pressure equipment process.

In the above pressing device for the timing sprocket on the crank of the crankshaft, the mounting hole penetrates through the outer side wall of the mounting block, the outer port of the mounting hole is in threaded connection with the adjusting screw, and the end part of the adjusting screw abuts against the small spring.

The adjusting screw is rotated to adjust the elastic force of the small spring, so that proper friction force can be always applied to the timing chain wheel, the timing chain wheel is prevented from being separated from the mounting groove under the self-weight, and the timing chain wheel pressed on the crank is ensured to be separated from the mounting block easily.

Compared with the prior art, this a pressure equipment device for timing sprocket on crank of bent axle has following advantage:

1. the press-fitting device can directly fix cranks for forming a crankshaft to press-fit a timing chain wheel by matching the positioning block, the lower tip and the floating tip, and ensures that a timing angle of the timing chain wheel after press-fitting meets design requirements by using a crank pin hole on the crank as a reference, so that the qualification rate of products is improved;

2. the crank used for forming the crankshaft is directly fixed to press fit the timing chain wheel, and the crank pin hole on the crank is used as a reference, so that the influence caused by errors between a connecting rod and a crank pin and between the crank pin and the crank pin hole is eliminated, the press fit precision is improved, and the structure is simpler relatively;

3. the synchronous press mounting of the bearing and the timing chain wheel can be realized by utilizing the pressure when the die carrier moves downwards, so that the assembly efficiency of the whole crankshaft is improved;

4. set up curved adjustment tank on the installation piece for the staff can rotate the installation piece through the adjustment tank and in order to carry out the fine setting of mounting groove and round pin post angle, has further guaranteed the pressure equipment precision.

Drawings

FIG. 1 is a front view of the press-fitting device for a timing sprocket on a crank of a crankshaft.

Fig. 2 is a perspective view of the press-fitting device for a timing sprocket on a crank of a crankshaft.

Fig. 3 is a sectional view taken along the line a-a in fig. 1.

FIG. 4 is a transverse cross-sectional view at the mounting block in the press fitting apparatus for a timing sprocket on a crank of a crankshaft.

Fig. 5 is a schematic cross-sectional view of the crank as installed in the orientation of fig. 3.

FIG. 6 is a schematic view of the timing sprocket and bearing press fit onto the crank.

In the figure, 1, a base; 2. a mold frame; 3. a die head; 3a, a body; 3a1, assembly holes; 3a2, vias; 3b, cushion blocks; 3b1, abdicating hole; 4. mounting blocks; 4a, mounting grooves; 4b, an adjusting groove; 4b1, groove section one; 4b2, groove section two; 4c, mounting holes; 5. a fastener; 6. a floating center; 6a, a sliding part; 7. positioning blocks; 8. a lower center; 9. a pin; 9a, a guide part; 9b, an outer convex arc surface; 10. a lower spring; 11. a guide sleeve; 12. an upper spring; 13. steel balls; 14. a small spring; 15. an adjusting screw; 16. a column; 17. blocking the cover; 18. a crank; 18a, a crank pin hole; 19. a timing sprocket; 20. and a bearing.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

As shown in fig. 1-3, the press-fitting device for the timing sprocket on the crank of the crankshaft comprises a base 1 and a mold frame 2 which can be driven by a driving part to move towards the base 1, wherein two parallel upright posts 16 are fixed on the base 1, the mold frame 2 is slidably arranged on the two upright posts 16, and the mold frame 2 is driven by an air cylinder or hydraulic pressure. The die head 3 is fixed on the die frame 2, the lower end face of the die head 3 is fixed with the mounting block 4 through the fastener 5, and the center of the mounting block 4 is provided with the mounting groove 4 with the same shape as the timing chain wheel 19 in a penetrating mode. A floating center 6 is arranged in the die head 3 in a sliding mode along the vertical direction, and the lower end of the floating center 6 penetrates out of the center of the mounting groove 4.

As shown in fig. 3, in detail, a fitting hole 3a1 is provided in the die head 3, a guide sleeve 11 is screwed into the fitting hole 3a1, and the upper end of the guide sleeve 11 extends out of the die holder 2 and is screwed with the cap 17. The upper end of the floating center 6 is provided with a sliding part 6a, the sliding part 6a is arranged in the guide sleeve 11 in a sliding manner, an upper spring 12 is arranged in the guide sleeve 11, the upper end and the lower end of the upper spring 12 are respectively abutted against the blanking cover 17 and the sliding part 6a, and the sliding part 6a is abutted against the bottom wall of the assembling hole 3a1 under the elastic force of the upper spring 12. The die head 3 is provided with a through hole 3a2 communicated with the assembly hole 3a1, and the floating center 6 passes through the through hole 3a2 and is in clearance fit with the through hole.

As shown in fig. 3 and 4, in this embodiment, the die head 3 includes a cylindrical body 3a and a cushion block 3b fixed to a lower end of the body 3a, the assembly holes 3a1 and the through holes 3a2 are both provided on the body 3a, the mounting block 4 is fixed to a lower end of the cushion block 3b, the number of the mounting blocks 4 is several, the mounting block 4 is provided with a plurality of arc-shaped adjustment grooves 4b along the vertical direction, each adjustment groove 4b is distributed around the floating tip 6, each adjustment groove 4b is located near an outer edge of the mounting block 4, and each fastener 5 passes through the corresponding adjustment groove 4 b. Further, the adjusting groove 4b can be arranged to sequentially comprise a groove section one 4b1 with a larger groove width and a groove section two 4b2 with a smaller groove width from bottom to top, the fastener 5 is a fastening screw, the rod of the fastener 5 is located in the groove section two 4b2, the head of the fastener 5 is located in the groove section one 4b1, and the height of the head of the fastener 5 is higher than the lower end face of the mounting block 4 or is flush with the lower end face of the mounting block 4. The center of the cushion block 3b is provided with a yielding hole 3b1 in a penetrating manner, the yielding hole 3b1 is located between the installation groove 4 and the through hole 3a2, the inner diameter of the yielding hole 3b1 is smaller than the maximum inner diameter of the installation groove 4, and the inner diameter of the yielding hole 3b1 is larger than that of the through hole 3a 2.

As shown in fig. 4, a friction structure for preventing the timing sprocket 19 from coming off is provided in the mounting groove 4. Mounting hole 4c has been seted up to the mounting block 4 lateral part, and mounting hole 4c is linked together with mounting groove 4, and the friction structure is including locating little spring 14 and the steel ball 13 in mounting hole 4c, and steel ball 13 stretches into in mounting groove 4 under little spring 14's elasticity effect part. Wherein, the mounting hole 4c runs through the outer cell wall of the mounting block 4, and the outer port department threaded connection of mounting hole 4c has adjusting screw 15, and the tip of adjusting screw 15 and little spring 14 are leaned on, and adjusting screw 15 of screwing can compress tightly little spring 14, and the adjusting screw 15 of unscrewing can loosen little spring 14, is equivalent to adjusting the elasticity that little spring 14 acted on steel ball 13, and then makes the frictional force of exerting on the sprocket 19 in right time along with changing.

As shown in fig. 1 and 2, a positioning block 7 is fixed on the base 1, a lower center 8 is arranged at the center of the positioning block 7, and the axis of the lower center 8 is collinear with the axis of the floating center 6. The upper end face of the positioning block 7 is a plane, a positioning hole is formed in the center of the upper end face of the positioning block 7, the lower tip 8 is arranged in the positioning hole in a sliding mode, a lower spring 10 is arranged in the positioning hole, and the elastic force of the lower spring 10 upwards acts on the lower tip 8. The lateral part threaded connection of locating piece 7 has stop screw, and the lateral part of lower top 8 is equipped with the spacing groove along upper and lower direction, and stop screw tip is located the spacing inslot, can prevent down top 8 to deviate from in the locating hole through the cooperation of stop screw and spacing groove. A pin 9 which can be inserted into a crank pin hole 18a on the crank 18 is arranged on the base 1 close to the positioning block 7, the pin 9 is close to the positioning block 7, and the upper end face of the pin 9 is higher than the upper end face of the positioning block 7. The periphery wall of the pin 9 is provided with two symmetrically distributed convex arc surfaces 9b, and the upper end of the pin 9 is provided with a guide part 9 a.

As shown in FIG. 5, when the timing sprocket 19 is pressed, the crank 18 for forming the crankshaft is first placed on the positioning block 7, the lower center 8 is pressed against the center hole of the large end of the crank 18, the large end surface of the crank 18 abuts against the upper end surface of the positioning block 7, and the pin 9 is inserted into the crank pin hole 18a of the crank 18, so that the positions of the crank 18 and the crank pin hole 18a are determined, and the bearing 20 is placed on the crank 18. Then, the timing chain wheel 19 needing press fitting is placed in the mounting groove 4, the steel balls 13 are pressed against the timing chain wheel 19 under the action of the elastic force of the small springs 14 to form friction force, and the timing chain wheel 19 cannot be separated due to the action of gravity.

Then, by driving the die holder 2 downward by air pressure or hydraulic pressure, the die 3 is pressed against the crank 18 along with the die holder 2. The floating center 6 moves downwards along with the die carrier 2 and is pressed against the small end center hole of the crank 18, and the crank 18 is firmly clamped by the floating center 6 and the lower center 8. The continuous downward movement of the die carrier 2 causes the crank 18 to exert a reaction force on the floating center 6, causing the floating center 6 to move upward relative to the die carrier 2 against the spring force of the upper spring 12, so that the small end of the crank 18 extends into the die head 3. With the further downward movement of the die carrier 2, the timing sprocket 19 is pressed to the position of the crank 18 near the large end to be fixed with the crank 18, and the downward pressure of the die head 3 is applied to the bearing 20 through the timing sprocket 19 to press the bearing 20 to the corresponding position to form fixation, which is equivalent to that the synchronous press-fitting of the timing sprocket 19 and the bearing 20 is completed through one action. Finally, the die carrier 2 is controlled to move upwards, the die head 3 is naturally separated from the timing sprocket 19 because the timing sprocket 19 is fixed on the crank 18, and the pressed state is as shown in fig. 6. Before actual press fitting, press fitting can be performed firstly, and if the timing angle is not within the design range after press fitting, a worker can loosen each fastener 5, so that the mounting block 4 can be rotated to finely adjust the angle between the mounting groove 4 and the axis of the pin 9, and the reliability of the timing angle after subsequent press fitting is ensured.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims

1. A press fitting device for a timing chain wheel on a crank of a crankshaft comprises a base (1) and a die carrier (2) which can be driven by a driving piece to move towards the base (1), wherein a die head (3) is fixed on the die carrier (2), a mounting block (4) is fixed on the lower end face of the die head (3) through a fastening piece (5), a mounting groove (4a) with the same shape as that of the timing chain wheel (19) penetrates through the center of the mounting block (4), a floating center (6) is arranged in the die head (3) in a sliding mode along the up-down direction, the lower end of the floating center (6) penetrates through the center of the mounting groove (4a), the press fitting device is characterized in that a positioning block (7) is fixed on the base (1), a lower center (8) is arranged at the center of the positioning block (7), the axis of the lower center (8) is collinear with the axis of the floating center (6), and a pin column (9) which can be inserted into a crank pin hole (18a, a friction structure for preventing the timing chain wheel (19) from falling off is arranged in the mounting groove (4 a).

2. The press-fitting device for the timing sprocket on the crank of the crankshaft as claimed in claim 1, wherein the upper end surface of the positioning block (7) is a plane, a positioning hole is formed in the center of the upper end surface of the positioning block (7), the lower center (8) is slidably arranged in the positioning hole, a lower spring (10) is arranged in the positioning hole, and the elastic force of the lower spring (10) upwards acts on the lower center (8).

3. A press-fitting device for a timing sprocket on a crank shaft as set forth in claim 2, wherein said pin (9) is provided at an upper end thereof with a guide portion (9a), and an outer peripheral wall of said pin (9) is provided with two symmetrically disposed outer convex arcuate surfaces (9 b).

4. The press-fitting device for the timing sprocket on the crank of the crankshaft as set forth in claim 1, wherein the number of the fastening members (5) is several, the mounting block (4) is provided with several arc-shaped adjustment grooves (4b) extending therethrough in the up-down direction, each adjustment groove (4b) is distributed around the floating center (6) and each adjustment groove (4b) is located near the outer edge of the mounting block (4), and each fastening member (5) passes through the corresponding adjustment groove (4 b).

5. The press-fitting device for the timing sprocket on the crank of the crankshaft as set forth in claim 4, wherein said adjustment groove (4b) comprises a first groove section (4b1) with a larger groove width and a second groove section (4b2) with a smaller groove width in sequence from bottom to top, the fastener (5) is a fastening screw, the shank of the fastener (5) is located in the second groove section (4b2), the head of the fastener (5) is located in the first groove section (4b1) and the head of the fastener (5) is higher than or flush with the lower end face of the mounting block (4).

6. The press-fitting device for the timing sprocket on the crank of the crankshaft as claimed in claim 1, 2, 3, 4 or 5, wherein the die head (3) is provided with a fitting hole (3a1), the fitting hole (3a1) is connected with a guide sleeve (11) in a threaded manner, the upper end of the floating center (6) is provided with a sliding part (6a), the sliding part (6a) is slidably arranged in the guide sleeve (11), the die head (3) is provided with a through hole (3a2) communicated with the fitting hole (3a1), the floating center (6) passes through the through hole (3a2) and is in clearance fit with the through hole, the guide sleeve (11) is provided with an upper spring (12), and the lower end face of the sliding part (6a) is abutted against the bottom wall of the fitting hole (3a1) under the elastic force of the upper spring (12).

7. The press-fitting device for the timing sprocket on the crank of the crankshaft as claimed in claim 6, wherein said die head (3) comprises a cylindrical body (3a) and a pad (3b) fixed to the lower end of the body (3a), the mounting block (4) is fixed to the lower end of the pad (3b), a yielding hole (3b1) is provided through the center of the pad (3b), the yielding hole (3b1) is located between the mounting groove (4a) and the through hole (3a2), the inner diameter of the yielding hole (3b1) is smaller than the maximum inner diameter of the mounting groove (4a) and the inner diameter of the yielding hole (3b1) is larger than the inner diameter of the through hole (3a 2).

8. The press-fitting device for the timing sprocket on the crank of the crankshaft as set forth in claim 7, wherein the mounting block (4) has a mounting hole (4c) formed in a side portion thereof, the mounting hole (4c) is communicated with the mounting groove (4a), the friction structure comprises a small spring (14) and a steel ball (13) disposed in the mounting hole (4c), and the steel ball (13) is partially extended into the mounting groove (4a) under the elastic force of the small spring (14).

9. The press-fitting device for the timing sprocket on the crank of the crankshaft as set forth in claim 8, wherein the mounting hole (4c) penetrates through the outer side wall of the mounting block (4), the outer port of the mounting hole (4c) is threadedly connected with an adjusting screw (15), and the end of the adjusting screw (15) abuts against the small spring (14).