Cam and gear pressing method and pressing tool

Abstract

This invention belongs to the field of mechanical parts processing technology, and relates to a method and fixture for pressing a cam and a gear. The pressing fixture includes a fixture base and a positioning pin and a pressing sleeve assembly respectively placed on the fixture base. The pressing sleeve assembly includes a pressing sleeve and a conical shaft located above the pressing sleeve, with the conical shaft inserted into the pressing sleeve. The pressing sleeve has an opening with an angle of 78°. The gear is held outside the positioning pin, and the cam is mounted on the gear. The pressing sleeve is pressed into the cam, and the scale line on the cam coincides with the angle of the opening on the pressing sleeve. The pressing sleeve has a slot that penetrates the axial direction of the pressing sleeve. The conical shaft is inserted into the pressing sleeve through the slot. This invention provides a method and fixture for pressing a cam and a gear, ensuring that there is no pressure deviation during pressing, and that the gear and cam fit tightly and seamlessly, resulting in high quality and meeting the design requirements.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of mechanical part processing, and relates to a cam and gear pressing method and pressing tool. BACKGROUND

[0002] A certain type of nozzle force regulator cam assembly Figure 1 and Figure 2 is a precision transmission part, and the cam assembly comprises a gear and a cam pressed on the gear. The two parts have the following problems: due to the complex structure of the cam and the gear, the cam and the gear have position limitations, there are problems of gear deflection, and the two part bonding surfaces are not real. There is a gap between the gear and the cam, which causes the cam line to be 78° out of tolerance when pressing the gear, so that the cam assembly cannot meet the design requirements, resulting in a large amount of scrap parts, seriously affecting the quality of the parts and product delivery, and causing great loss. SUMMARY

[0003] In order to solve the deviation problem in the pressing of the existing cam and gear, the present application provides a cam and gear pressing method and pressing tool, which can ensure that the pressing will not be deflected, the gear and the cam will be closely bonded without gap, the quality will be high, and the design requirements will be met.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0005] A cam and gear pressing tool, comprising a clamp base and a positioning pin and a pressing sleeve assembly respectively arranged on the clamp base; the pressing sleeve assembly comprises a pressing sleeve and a tapered shaft located above the pressing sleeve, and the tapered shaft is clamped into the pressing sleeve; a fan-shaped opening is formed in the pressing sleeve, and the included angle of the fan-shaped opening is 78°; the gear is clamped outside the positioning pin, the cam is installed on the gear, the pressing sleeve is pressed into the cam, and the scale line provided on the cam coincides with the axis of the fan-shaped opening on the pressing sleeve.

[0006] Further, a slot hole penetrating the pressing sleeve in the axial direction is provided on the pressing sleeve; and the tapered shaft is clamped into the pressing sleeve through the slot hole.

[0007] Further, the pressing sleeve assembly further comprises a limiting rod; and the limiting rod is connected with the clamp base by penetrating the pressing sleeve from top to bottom.

[0008] Further, the pressing sleeve assembly further comprises a limiting hole provided on the pressing sleeve and penetrating the pressing sleeve in the axial direction; and the limiting rod is connected with the clamp base by penetrating the limiting hole.

[0009] Further, the cam and gear pressing tool further comprises a movable tightening assembly arranged on the clamp base; the axial direction of the positioning pin is perpendicular to the axial direction of the movable tightening assembly; and the movable tightening assembly moves horizontally along the radial direction of the positioning pin and tightens the gear.

[0010] Further, the movable pressing assembly comprises a screw rod and a movable directional block connected with the screw rod; the movable directional block is arranged on the clamp base, and the screw rod is arranged above the clamp base and movably connected with the clamp base; the axial direction of the screw rod is perpendicular to the axial direction of the positioning pin; the screw rod rotates and drives the movable directional block to move horizontally along the axial direction of the screw rod and press against the gear.

[0011] Further, a tooth-shaped groove is arranged on the side wall of the movable directional block, and the tooth-shaped groove is engaged with the teeth on the gear.

[0012] A pressing method of the cam and gear pressing tool, comprising the following steps:

[0013] 1) respectively pretreat the gear and the cam, and then cool the cam in liquid nitrogen to boiling;

[0014] 2) screw the conical shaft into the pressing sleeve to form a pressing sleeve assembly, the conical shaft is coaxial with the pressing sleeve, and the conical shaft expands the pressing sleeve outward;

[0015] 3) clamp the pretreated gear on the positioning pin of the clamp base, and the movable directional block abuts against the middle teeth of the gear;

[0016] 4) install the cooled cam in step 2) on the gear, and press the pressing sleeve on the cam in step 2) to make the engraved line on the cam coincide with the axial line at the 78° included angle of the fan-shaped opening on the pressing sleeve;

[0017] 5) press the pressing sleeve with the hydraulic machine for 10s to press the cam to abut against the T face of the gear.

[0018] Further, in step 1), the boiling time is 20 min, and in step 5), the maximum pressure of the hydraulic machine is 2.5 MP.

[0019] The beneficial effects of the present application are:

[0020] The present application adjusts the position angle of the cam by the 78° fan-shaped opening arranged on the pressing sleeve through the pressing tool; at the same time, the conical shaft is pressed into the pressing sleeve to ensure the tightness of the pressing sleeve and the cam, the conical shaft is used to press the cam and position the cam, the engraved line of the cam is aligned with the engraved line of the conical shaft, the cam is pressed into the gear, the cam is in close contact with the size joint surface, and the angular position is 78° qualified; by applying this pressing method, the problem of large amount of scrap parts caused by the pressing quality of the cam and the gear is effectively solved, the phenomena such as gear pressing deviation, gap between the two parts, cam engraved line and gear position angle, deformation of the assembly after pressing, etc. are avoided, and the processing quality of the parts is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of a gear;

[0022] Figure 2 is a schematic diagram of the cam;

[0023] Figure 3 is a schematic diagram of the cam and gear after pressing together according to the present application;

[0024] Figure 4 is a schematic diagram of the fixture base according to the present application;

[0025] Figure 5 is a schematic diagram of the pressing sleeve mandrel according to the present application; Figure 5 (a) is a schematic diagram of the pressing sleeve from the top view; Figure 5 (b) is the A-A cross-sectional view of (a); Figure 5 (a) is a schematic diagram of the pressing sleeve from the top view;

[0026] Figure 6 is a schematic diagram of the taper mandrel according to the present application; Figure 6 (a) is a schematic diagram of the slot hole on the pressing sleeve; Figure 6 (b) is a schematic diagram of the mandrel;

[0027] wherein:

[0028] 1 - gear; 2 - cam; 3 - fixture base; 4 - movable orientation block; 5 - pressing sleeve; 6 - taper mandrel; 7 - positioning pin; 8 - limiting rod; 9 - screw rod. DETAILED DESCRIPTION

[0029] The present application will be described in detail with reference to the accompanying drawings and examples.

[0030] Referring to Figure 3 , a cam and gear pressing tool, comprising a fixture base 3 and a positioning pin 7 and a pressing sleeve assembly respectively arranged on the fixture base 3; the pressing sleeve assembly comprises a pressing sleeve 5 and a taper mandrel 6 arranged above the pressing sleeve 5, the taper mandrel 6 is clamped into the pressing sleeve 5; a fan-shaped opening is formed on the pressing sleeve 5, the included angle of the fan-shaped opening is 78°, the gear 1 is clamped on the outside of the positioning pin 7, the cam 2 is installed on the gear 1, the pressing sleeve 5 is pressed into the cam 2, and the scale line provided on the cam 2 coincides with the axis of the included angle of the fan-shaped opening on the pressing sleeve 5.

[0031] Referring to Figure 4 , the positioning pin 7 is in the shape of inverted T with the upper part being small and the lower part being large, comprising an upper small cylinder and a lower large cylinder, and the gear 1 is clamped on the stepped surface of the positioning pin 7.

[0032] Referring to Figure 5 and Figure 6 , a slot hole is provided on the pressing sleeve 5 and penetrates the pressing sleeve 5 axially, and the taper mandrel 6 is clamped into the pressing sleeve 5 through the slot hole. The pressing sleeve assembly further comprises a limiting rod 8; the limiting rod 8 is connected with the fixture base 3 by penetrating the pressing sleeve 5 from top to bottom. The pressing sleeve assembly further comprises a limiting hole provided on the pressing sleeve 5 and penetrating the pressing sleeve 5 axially; the limiting rod 8 is connected with the fixture base 3 by penetrating the limiting hole.

[0033] Specifically, the pressing sleeve 5 is a circular plate, a sector opening is formed on the circular plate, the sector opening extends from the edge to the center of the circular plate, the included angle of the sector opening is 78°, an included angle line is marked at the included angle, the included angle line is the same as the axial direction of the pressing sleeve 5, and the pressing sleeve 5 is further provided with a through slot hole and a limiting hole which are coaxial with the pressing sleeve 5.

[0034] Referring to Figure 3 , the cam and gear pressing tool further comprises a movable clamping assembly arranged on the clamp base 3; the axial direction of the positioning pin 7 is perpendicular to the axial direction of the movable clamping assembly, and the movable clamping assembly moves horizontally along the radial direction of the positioning pin 7 and clamps the gear 1.

[0035] Referring to Figure 3 and Figure 4 , the movable clamping assembly comprises a screw rod 9 and a movable directional block 4 connected with the screw rod 9; the movable directional block 4 is arranged on the clamp base 3, and the screw rod 9 is arranged above the clamp base 3 and is movably connected with the clamp base 3; the axial direction of the screw rod 9 is perpendicular to the axial direction of the positioning pin 7, and the screw rod 9 rotates and drives the movable directional block 4 to move horizontally along the axial direction of the screw rod 9 and clamp the gear 1.

[0036] Specifically, a fixed block is arranged on the right side wall of the clamp base 3, the height of the fixed block is higher than that of the clamp base 3, the screw rod 9 is arranged on the right side of the fixed block, one end of the screw rod 9 is coaxial with the fixed block and is connected with the movable directional block 4 arranged beside the gear 1, a toothed groove is arranged on the side wall of the movable directional block 4, the toothed groove is engaged with the teeth on the gear 1, the screw rod 9 drives the movable directional block 4 to move horizontally along the axial direction of the screw rod 9 and clamp the gear 1, and the other end of the screw rod 9 is fastened with the fixed block through a nut.

[0037] A pressing method of a cam and gear pressing tool, comprising the following steps:

[0038] 1) The gear 1 and the cam 2 are pretreated respectively, and then the cam 2 is cooled to boiling in liquid nitrogen.

[0039] The pretreatment is to clean the oil stains on the cam 2 and the gear 1, and clean the two parts completely. The cam 2 is cooled to boiling in liquid nitrogen and kept for 20 minutes, and then stopped.

[0040] 2) The taper shaft 6 is screwed into the pressing sleeve 5 to form a pressing sleeve assembly, the taper shaft 6 is coaxial with the pressing sleeve 5, and the taper shaft 6 expands the pressing sleeve 5 outward.

[0041] The taper shaft 6 is screwed into the slot hole on the pressing sleeve 5 through threads, and the pressing sleeve 5 is expanded to ensure that the pressing sleeve 5 has a certain tightness during pressing the cam 2, so as to avoid the gap between the pressing sleeve 5 and the cam 2, and the movement of the pressing sleeve 5 during pressing.

[0042] 3) The pretreated gear 1 is clamped on the positioning pin 7 of the fixture base 3, and the movable orientation block 4 is moved to the left by rotating the screw rod 9 to abut against the middle teeth of the gear 1, so that the gear 1 cannot rotate.

[0043] 4) The cooled cam 2 in step 2) is installed on the gear 1, and the pressing sleeve 5 on the pressing sleeve assembly in step 2) is pressed on the cam 2, so that the engraved line on the cam 2 is coincided with the axis at the 78° included angle of the sector-shaped opening on the pressing sleeve 5.

[0044] The cam 2 is installed on the gear 1, the pressing sleeve 5 passes through the hole center on the cam 2, the engraved line arranged on the cam 2 is adjusted to be coincided with the engraved line on the pressing sleeve 5, and the position angle is 78°.

[0045] 5) The hydraulic machine is used to press on the pressing sleeve 5 for 10s, and the cam 2 is pressed to abut against the T face of the gear 1. The maximum pressure of the hydraulic machine is 2.5MP.

[0046] After the pressing is completed, the combined cam 2 and gear 1 are taken out, and visual inspection is performed on the two parts to check whether the two parts are seamlessly bonded and whether the parts are deformed.

[0047] The pressing process method has been applied to the machining of batch parts. By applying the pressing method, the problem of large amount of scrapped parts due to the pressing quality of the cam and the gear is effectively solved, the phenomena such as gear pressing deviation, seam between the bonding surfaces of the two parts, cam engraved line and gear position angle out-of-tolerance pressing, deformation of the combined assembly after pressing, etc. are avoided, and the machining quality and efficiency of the parts are improved.

Claims

1. A cam and gear press fitting tool characterized by, The cam and gear pressing tool comprises a clamp base (3), a positioning pin (7) and a pressing sleeve assembly arranged on the clamp base (3) respectively; the pressing sleeve assembly comprises a pressing sleeve (5) and a tapered shaft (6) arranged above the pressing sleeve (5) and clamped into the pressing sleeve (5); a sector opening is formed on the pressing sleeve (5), the included angle of the sector opening is 78°, a gear (1) is clamped outside the positioning pin (7), a cam (2) is arranged on the gear (1), the pressing sleeve (5) is pressed into the cam (2), and the axis of the scale line arranged on the cam (2) coincides with the axis of the sector opening on the pressing sleeve (5) at the included angle position; The pressing sleeve assembly further comprises a limiting rod (8); the limiting rod (8) is connected with the clamp base (3) by penetrating the pressing sleeve (5) from top to bottom; The pressing sleeve assembly further comprises a limiting hole arranged on the pressing sleeve (5) and penetrating the pressing sleeve (5) axially; the limiting rod (8) is connected with the clamp base (3) by penetrating the limiting hole; The cam and gear pressing tool further comprises a movable tightening assembly arranged on the clamp base (3); the axial direction of the positioning pin (7) is perpendicular to the axial direction of the movable tightening assembly; the movable tightening assembly moves horizontally along the radial direction of the positioning pin (7) and tightens the gear (1).

2. The cam and gear press fitting tool according to claim 1, wherein A slot hole penetrating the pressing sleeve (5) axially is arranged on the pressing sleeve (5); the tapered shaft (6) is clamped into the pressing sleeve (5) through the slot hole.

3. The cam and gear press fitting tool according to claim 1, wherein The movable tightening assembly comprises a screw rod (9) and a movable directional block (4) connected with the screw rod (9); the movable directional block (4) is arranged on the clamp base (3), and the screw rod (9) is arranged above the clamp base (3) and movably connected with the clamp base (3); the axial direction of the screw rod (9) is perpendicular to the axial direction of the positioning pin (7); the screw rod (9) rotates and drives the movable directional block (4) to move horizontally along the axial direction of the screw rod (9) and tightens the gear (1).

4. The cam and gear press fitting tool according to claim 3, wherein A tooth-shaped groove is arranged on the side wall of the movable directional block (4) and engaged with the tooth on the gear (1).

5. A press fitting method based on the press fitting jig for cam and gear of claim 4, characterized by, The pressing method comprises the following steps: 1) respectively pretreat the gear (1) and the cam (2), and then cool the cam (2) in liquid nitrogen to boiling; 2) screw the tapered shaft (6) into the pressing sleeve (5) to form a pressing sleeve assembly, the tapered shaft (6) is coaxial with the pressing sleeve (5), and the tapered shaft (6) expands the pressing sleeve (5) outward; 3) clamp the pretreated gear (1) on the positioning pin (7) of the clamp base (3), and make the movable directional block (4) abut against the middle tooth of the gear (1); 4) install the cam (2) after step 1) on the gear (1), press the pressing sleeve (5) on the pressing sleeve assembly of step 2) on the cam (2), and make the scale line on the cam (2) coincide with the axis at the 78° included angle position of the sector opening on the pressing sleeve (5); 5) press the pressing sleeve (5) by using a hydraulic machine for 10s, and press the cam (2) to abut against the T face of the gear (1).

6. The press-fit method of claim 5, wherein, In step 1), the boiling time is 20 min, and in step 5), the maximum pressure of the hydraulic machine is 2.5 MP.

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